item.cc 238 KB
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/* Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.
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   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
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   the Free Software Foundation; version 2 of the License.
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   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
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   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


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#ifdef USE_PRAGMA_IMPLEMENTATION
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#pragma implementation				// gcc: Class implementation
#endif
#include "mysql_priv.h"
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#include <mysql.h>
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#include <m_ctype.h>
#include "my_dir.h"
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#include "sp_rcontext.h"
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#include "sp_head.h"
#include "sql_trigger.h"
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#include "sql_select.h"
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const String my_null_string("NULL", 4, default_charset_info);

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static int save_field_in_field(Field *from, bool *null_value,
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                               Field *to, bool no_conversions);

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/****************************************************************************/

/* Hybrid_type_traits {_real} */

void Hybrid_type_traits::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= NOT_FIXED_DEC;
  item->max_length= item->float_length(arg->decimals);
}

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static const Hybrid_type_traits real_traits_instance;
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const Hybrid_type_traits *Hybrid_type_traits::instance()
{
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  return &real_traits_instance;
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}


my_decimal *
Hybrid_type_traits::val_decimal(Hybrid_type *val, my_decimal *to) const
{
  double2my_decimal(E_DEC_FATAL_ERROR, val->real, val->dec_buf);
  return val->dec_buf;
}


String *
Hybrid_type_traits::val_str(Hybrid_type *val, String *to, uint8 decimals) const
{
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  to->set_real(val->real, decimals, &my_charset_bin);
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  return to;
}

/* Hybrid_type_traits_decimal */
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static const Hybrid_type_traits_decimal decimal_traits_instance;
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const Hybrid_type_traits_decimal *Hybrid_type_traits_decimal::instance()
{
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  return &decimal_traits_instance;
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}


void
Hybrid_type_traits_decimal::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= arg->decimals;
  item->max_length= min(arg->max_length + DECIMAL_LONGLONG_DIGITS,
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                        DECIMAL_MAX_STR_LENGTH);
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}


void Hybrid_type_traits_decimal::set_zero(Hybrid_type *val) const
{
  my_decimal_set_zero(&val->dec_buf[0]);
  val->used_dec_buf_no= 0;
}


void Hybrid_type_traits_decimal::add(Hybrid_type *val, Field *f) const
{
  my_decimal_add(E_DEC_FATAL_ERROR,
                 &val->dec_buf[val->used_dec_buf_no ^ 1],
                 &val->dec_buf[val->used_dec_buf_no],
                 f->val_decimal(&val->dec_buf[2]));
  val->used_dec_buf_no^= 1;
}


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/**
  @todo
  what is '4' for scale?
*/
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void Hybrid_type_traits_decimal::div(Hybrid_type *val, ulonglong u) const
{
  int2my_decimal(E_DEC_FATAL_ERROR, u, TRUE, &val->dec_buf[2]);
  /* XXX: what is '4' for scale? */
  my_decimal_div(E_DEC_FATAL_ERROR,
                 &val->dec_buf[val->used_dec_buf_no ^ 1],
                 &val->dec_buf[val->used_dec_buf_no],
                 &val->dec_buf[2], 4);
  val->used_dec_buf_no^= 1;
}


longlong
Hybrid_type_traits_decimal::val_int(Hybrid_type *val, bool unsigned_flag) const
{
  longlong result;
  my_decimal2int(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                 unsigned_flag, &result);
  return result;
}


double
Hybrid_type_traits_decimal::val_real(Hybrid_type *val) const
{
  my_decimal2double(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                    &val->real);
  return val->real;
}


String *
Hybrid_type_traits_decimal::val_str(Hybrid_type *val, String *to,
                                    uint8 decimals) const
{
  my_decimal_round(E_DEC_FATAL_ERROR, &val->dec_buf[val->used_dec_buf_no],
                   decimals, FALSE, &val->dec_buf[2]);
  my_decimal2string(E_DEC_FATAL_ERROR, &val->dec_buf[2], 0, 0, 0, to);
  return to;
}

/* Hybrid_type_traits_integer */
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static const Hybrid_type_traits_integer integer_traits_instance;
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const Hybrid_type_traits_integer *Hybrid_type_traits_integer::instance()
{
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  return &integer_traits_instance;
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}

void
Hybrid_type_traits_integer::fix_length_and_dec(Item *item, Item *arg) const
{
  item->decimals= 0;
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  item->max_length= MY_INT64_NUM_DECIMAL_DIGITS;
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  item->unsigned_flag= 0;
}

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/*****************************************************************************
** Item functions
*****************************************************************************/

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/**
  Init all special items.
*/
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void item_init(void)
{
  item_user_lock_init();
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  uuid_short_init();
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}

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/**
  @todo
    Make this functions class dependent
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*/
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bool Item::val_bool()
{
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  switch(result_type()) {
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  case INT_RESULT:
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    return val_int() != 0;
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  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *val= val_decimal(&decimal_value);
    if (val)
      return !my_decimal_is_zero(val);
    return 0;
  }
  case REAL_RESULT:
  case STRING_RESULT:
    return val_real() != 0.0;
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
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    return 0;                                   // Wrong (but safe)
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  }
}


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String *Item::val_string_from_real(String *str)
{
  double nr= val_real();
  if (null_value)
    return 0;					/* purecov: inspected */
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  str->set_real(nr,decimals, &my_charset_bin);
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  return str;
}


String *Item::val_string_from_int(String *str)
{
  longlong nr= val_int();
  if (null_value)
    return 0;
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  str->set_int(nr, unsigned_flag, &my_charset_bin);
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  return str;
}


String *Item::val_string_from_decimal(String *str)
{
  my_decimal dec_buf, *dec= val_decimal(&dec_buf);
  if (null_value)
    return 0;
  my_decimal_round(E_DEC_FATAL_ERROR, dec, decimals, FALSE, &dec_buf);
  my_decimal2string(E_DEC_FATAL_ERROR, &dec_buf, 0, 0, 0, str);
  return str;
}


my_decimal *Item::val_decimal_from_real(my_decimal *decimal_value)
{
  double nr= val_real();
  if (null_value)
    return 0;
  double2my_decimal(E_DEC_FATAL_ERROR, nr, decimal_value);
  return (decimal_value);
}


my_decimal *Item::val_decimal_from_int(my_decimal *decimal_value)
{
  longlong nr= val_int();
  if (null_value)
    return 0;
  int2my_decimal(E_DEC_FATAL_ERROR, nr, unsigned_flag, decimal_value);
  return decimal_value;
}


my_decimal *Item::val_decimal_from_string(my_decimal *decimal_value)
{
  String *res;
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  if (!(res= val_str(&str_value)))
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    return 0;
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  if (str2my_decimal(E_DEC_FATAL_ERROR & ~E_DEC_BAD_NUM,
                     res->ptr(), res->length(), res->charset(),
                     decimal_value) & E_DEC_BAD_NUM)
  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "DECIMAL",
                        str_value.c_ptr());
  }
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  return decimal_value;
}


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my_decimal *Item::val_decimal_from_date(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed == 1);
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  MYSQL_TIME ltime;
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  if (get_date(&ltime, TIME_FUZZY_DATE))
  {
    my_decimal_set_zero(decimal_value);
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    null_value= 1;                               // set NULL, stop processing
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    return 0;
  }
  return date2my_decimal(&ltime, decimal_value);
}


my_decimal *Item::val_decimal_from_time(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed == 1);
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  MYSQL_TIME ltime;
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  if (get_time(&ltime))
  {
    my_decimal_set_zero(decimal_value);
    return 0;
  }
  return date2my_decimal(&ltime, decimal_value);
}


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double Item::val_real_from_decimal()
{
  /* Note that fix_fields may not be called for Item_avg_field items */
  double result;
  my_decimal value_buff, *dec_val= val_decimal(&value_buff);
  if (null_value)
    return 0.0;
  my_decimal2double(E_DEC_FATAL_ERROR, dec_val, &result);
  return result;
}


longlong Item::val_int_from_decimal()
{
  /* Note that fix_fields may not be called for Item_avg_field items */
  longlong result;
  my_decimal value, *dec_val= val_decimal(&value);
  if (null_value)
    return 0;
  my_decimal2int(E_DEC_FATAL_ERROR, dec_val, unsigned_flag, &result);
  return result;
}

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int Item::save_time_in_field(Field *field)
{
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  MYSQL_TIME ltime;
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  if (get_time(&ltime))
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    return set_field_to_null_with_conversions(field, 0);
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  field->set_notnull();
  return field->store_time(&ltime, MYSQL_TIMESTAMP_TIME);
}


int Item::save_date_in_field(Field *field)
{
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  MYSQL_TIME ltime;
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  if (get_date(&ltime, TIME_FUZZY_DATE))
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    return set_field_to_null_with_conversions(field, 0);
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  field->set_notnull();
  return field->store_time(&ltime, MYSQL_TIMESTAMP_DATETIME);
}

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/*
  Store the string value in field directly

  SYNOPSIS
    Item::save_str_value_in_field()
    field   a pointer to field where to store
    result  the pointer to the string value to be stored

  DESCRIPTION
    The method is used by Item_*::save_in_field implementations
    when we don't need to calculate the value to store
    See Item_string::save_in_field() implementation for example

  IMPLEMENTATION
    Check if the Item is null and stores the NULL or the
    result value in the field accordingly.

  RETURN
    Nonzero value if error
*/

int Item::save_str_value_in_field(Field *field, String *result)
{
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
  return field->store(result->ptr(), result->length(),
		      collation.collation);
}


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Item::Item():
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  is_expensive_cache(-1), rsize(0), name(0), orig_name(0), name_length(0),
  fixed(0), is_autogenerated_name(TRUE),
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  collation(&my_charset_bin, DERIVATION_COERCIBLE)
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{
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  marker= 0;
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  maybe_null=null_value=with_sum_func=with_field=unsigned_flag=0;
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  in_rollup= 0;
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  decimals= 0; max_length= 0;
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  with_subselect= 0;
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  cmp_context= IMPOSSIBLE_RESULT;
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   /* Initially this item is not attached to any JOIN_TAB. */
  join_tab_idx= MAX_TABLES;
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  /* Put item in free list so that we can free all items at end */
  THD *thd= current_thd;
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  next= thd->free_list;
  thd->free_list= this;
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  /*
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    Item constructor can be called during execution other then SQL_COM
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    command => we should check thd->lex->current_select on zero (thd->lex
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    can be uninitialised)
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  */
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  if (thd->lex->current_select)
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  {
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    enum_parsing_place place= 
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      thd->lex->current_select->parsing_place;
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    if (place == SELECT_LIST ||
	place == IN_HAVING)
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      thd->lex->current_select->select_n_having_items++;
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  }
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}

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/**
  Constructor used by Item_field, Item_ref & aggregate (sum)
  functions.

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  Used for duplicating lists in processing queries with temporary
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  tables.
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*/
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Item::Item(THD *thd, Item *item):
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  join_tab_idx(item->join_tab_idx),
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  is_expensive_cache(-1),
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  rsize(0),
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  str_value(item->str_value),
  name(item->name),
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  orig_name(item->orig_name),
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  max_length(item->max_length),
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  name_length(item->name_length),
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  marker(item->marker),
  decimals(item->decimals),
  maybe_null(item->maybe_null),
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  in_rollup(item->in_rollup),
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  null_value(item->null_value),
  unsigned_flag(item->unsigned_flag),
  with_sum_func(item->with_sum_func),
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  with_field(item->with_field),
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  fixed(item->fixed),
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  is_autogenerated_name(item->is_autogenerated_name),
  with_subselect(item->with_subselect),
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  collation(item->collation),
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  cmp_context(item->cmp_context)
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{
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  next= thd->free_list;				// Put in free list
  thd->free_list= this;
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}

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uint Item::decimal_precision() const
{
  Item_result restype= result_type();

  if ((restype == DECIMAL_RESULT) || (restype == INT_RESULT))
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  {
    uint prec= 
      my_decimal_length_to_precision(max_length, decimals, unsigned_flag);
    return min(prec, DECIMAL_MAX_PRECISION);
  }
  return min(max_length, DECIMAL_MAX_PRECISION);
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}


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void Item::print_item_w_name(String *str, enum_query_type query_type)
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{
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  print(str, query_type);

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  if (name)
  {
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    THD *thd= current_thd;
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    str->append(STRING_WITH_LEN(" AS "));
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    append_identifier(thd, str, name, (uint) strlen(name));
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  }
}


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void Item::cleanup()
{
  DBUG_ENTER("Item::cleanup");
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  DBUG_PRINT("enter", ("this: %p", this));
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  fixed=0;
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  marker= 0;
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  join_tab_idx= MAX_TABLES;
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  if (orig_name)
    name= orig_name;
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  DBUG_VOID_RETURN;
}

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/**
  cleanup() item if it is 'fixed'.
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  @param arg   a dummy parameter, is not used here
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*/

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bool Item::cleanup_processor(uchar *arg)
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{
  if (fixed)
    cleanup();
  return FALSE;
}


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/**
  rename item (used for views, cleanup() return original name).
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  @param new_name	new name of item;
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*/

void Item::rename(char *new_name)
{
  /*
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    we can compare pointers to names here, because if name was not changed,
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    pointer will be same
  */
  if (!orig_name && new_name != name)
    orig_name= name;
  name= new_name;
}


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/**
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  Traverse item tree possibly transforming it (replacing items).
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  This function is designed to ease transformation of Item trees.
  Re-execution note: every such transformation is registered for
  rollback by THD::change_item_tree() and is rolled back at the end
  of execution by THD::rollback_item_tree_changes().
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  Therefore:
  - this function can not be used at prepared statement prepare
  (in particular, in fix_fields!), as only permanent
  transformation of Item trees are allowed at prepare.
  - the transformer function shall allocate new Items in execution
  memory root (thd->mem_root) and not anywhere else: allocated
  items will be gone in the end of execution.
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  If you don't need to transform an item tree, but only traverse
  it, please use Item::walk() instead.
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  @param transformer    functor that performs transformation of a subtree
  @param arg            opaque argument passed to the functor
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  @return
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    Returns pointer to the new subtree root.  THD::change_item_tree()
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    should be called for it if transformation took place, i.e. if a
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    pointer to newly allocated item is returned.
*/

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Item* Item::transform(Item_transformer transformer, uchar *arg)
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{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());

  return (this->*transformer)(arg);
}


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/**
  Create and set up an expression cache for this item

  @param thd             Thread handle
  @param depends_on      List of the expression parameters

  @details
  The function creates an expression cache for an item and its parameters
  specified by the 'depends_on' list. Then the expression cache is placed
  into a cache wrapper that is returned as the result of the function.

  @returns
  A pointer to created wrapper item if successful, NULL - otherwise
*/

Item* Item::set_expr_cache(THD *thd, List<Item *> &depends_on)
{
  DBUG_ENTER("Item::set_expr_cache");
  Item_cache_wrapper *wrapper;
  if ((wrapper= new Item_cache_wrapper(this)) &&
      !wrapper->fix_fields(thd, (Item**)&wrapper))
  {
    if (wrapper->set_cache(thd, depends_on))
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      DBUG_RETURN(NULL);
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    DBUG_RETURN(wrapper);
  }
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  DBUG_RETURN(NULL);
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}


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Item_ident::Item_ident(Name_resolution_context *context_arg,
                       const char *db_name_arg,const char *table_name_arg,
		       const char *field_name_arg)
  :orig_db_name(db_name_arg), orig_table_name(table_name_arg),
   orig_field_name(field_name_arg), context(context_arg),
   db_name(db_name_arg), table_name(table_name_arg),
   field_name(field_name_arg),
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   alias_name_used(FALSE), cached_field_index(NO_CACHED_FIELD_INDEX),
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   cached_table(0), depended_from(0), can_be_depended(TRUE)
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{
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  name = (char*) field_name_arg;
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}

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Item_ident::Item_ident(TABLE_LIST *view_arg, const char *field_name_arg)
  :orig_db_name(NullS), orig_table_name(view_arg->table_name),
   orig_field_name(field_name_arg), context(&view_arg->view->select_lex.context),
   db_name(NullS), table_name(view_arg->alias),
   field_name(field_name_arg),
   alias_name_used(FALSE), cached_field_index(NO_CACHED_FIELD_INDEX),
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   cached_table(NULL), depended_from(NULL), can_be_depended(TRUE)
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{
  name = (char*) field_name_arg;
}


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/**
  Constructor used by Item_field & Item_*_ref (see Item comment)
*/
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Item_ident::Item_ident(THD *thd, Item_ident *item)
  :Item(thd, item),
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   orig_db_name(item->orig_db_name),
   orig_table_name(item->orig_table_name), 
   orig_field_name(item->orig_field_name),
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   context(item->context),
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   db_name(item->db_name),
   table_name(item->table_name),
   field_name(item->field_name),
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   alias_name_used(item->alias_name_used),
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   cached_field_index(item->cached_field_index),
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   cached_table(item->cached_table),
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   depended_from(item->depended_from),
   can_be_depended(item->can_be_depended)
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{}
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void Item_ident::cleanup()
{
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  DBUG_ENTER("Item_ident::cleanup");
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#ifdef CANT_BE_USED_AS_MEMORY_IS_FREED
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		       db_name ? db_name : "(null)",
                       orig_db_name ? orig_db_name : "(null)",
		       table_name ? table_name : "(null)",
                       orig_table_name ? orig_table_name : "(null)",
		       field_name ? field_name : "(null)",
                       orig_field_name ? orig_field_name : "(null)"));
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#endif
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  Item::cleanup();
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  db_name= orig_db_name; 
  table_name= orig_table_name;
  field_name= orig_field_name;
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  /* Store if this Item was depended */
  can_be_depended= test(depended_from);
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  DBUG_VOID_RETURN;
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}

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bool Item_ident::remove_dependence_processor(uchar * arg)
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{
  DBUG_ENTER("Item_ident::remove_dependence_processor");
  if (depended_from == (st_select_lex *) arg)
    depended_from= 0;
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  context= &((st_select_lex *) arg)->context;
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  DBUG_RETURN(0);
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}


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/**
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  Store the pointer to this item field into a list if not already there.

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  The method is used by Item::walk to collect all unique Item_field objects
  from a tree of Items into a set of items represented as a list.
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  Item_cond::walk() and Item_func::walk() stop the evaluation of the
  processor function for its arguments once the processor returns
  true.Therefore in order to force this method being called for all item
  arguments in a condition the method must return false.
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  @param arg  pointer to a List<Item_field>
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  @return
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    FALSE to force the evaluation of collect_item_field_processor
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    for the subsequent items.
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*/

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bool Item_field::collect_item_field_processor(uchar *arg)
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{
  DBUG_ENTER("Item_field::collect_item_field_processor");
  DBUG_PRINT("info", ("%s", field->field_name ? field->field_name : "noname"));
  List<Item_field> *item_list= (List<Item_field>*) arg;
  List_iterator<Item_field> item_list_it(*item_list);
  Item_field *curr_item;
  while ((curr_item= item_list_it++))
  {
    if (curr_item->eq(this, 1))
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      DBUG_RETURN(FALSE); /* Already in the set. */
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  }
  item_list->push_back(this);
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  DBUG_RETURN(FALSE);
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}


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bool Item_field::add_field_to_set_processor(uchar *arg)
{
  DBUG_ENTER("Item_field::add_field_to_set_processor");
  DBUG_PRINT("info", ("%s", field->field_name ? field->field_name : "noname"));
  TABLE *table= (TABLE *) arg;
  if (field->table == table)
    bitmap_set_bit(&table->tmp_set, field->field_index);
  DBUG_RETURN(FALSE);
}

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/**
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  Check if an Item_field references some field from a list of fields.

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  Check whether the Item_field represented by 'this' references any
  of the fields in the keyparts passed via 'arg'. Used with the
  method Item::walk() to test whether any keypart in a sequence of
  keyparts is referenced in an expression.
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  @param arg   Field being compared, arg must be of type Field
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  @retval
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    TRUE  if 'this' references the field 'arg'
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  @retval
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    FALSE otherwise
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*/
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bool Item_field::find_item_in_field_list_processor(uchar *arg)
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{
  KEY_PART_INFO *first_non_group_part= *((KEY_PART_INFO **) arg);
  KEY_PART_INFO *last_part= *(((KEY_PART_INFO **) arg) + 1);
  KEY_PART_INFO *cur_part;

  for (cur_part= first_non_group_part; cur_part != last_part; cur_part++)
  {
    if (field->eq(cur_part->field))
      return TRUE;
  }
  return FALSE;
}


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/*
  Mark field in read_map

  NOTES
    This is used by filesort to register used fields in a a temporary
    column read set or to register used fields in a view
*/

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bool Item_field::register_field_in_read_map(uchar *arg)
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{
  TABLE *table= (TABLE *) arg;
  if (field->table == table || !table)
    bitmap_set_bit(field->table->read_set, field->field_index);
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  if (field->vcol_info && field->vcol_info->expr_item)
    return field->vcol_info->expr_item->walk(&Item::register_field_in_read_map, 
                                             1, arg);
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  return 0;
}

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/*
  @brief
  Mark field in bitmap supplied as *arg
*/

bool Item_field::register_field_in_bitmap(uchar *arg)
{
  MY_BITMAP *bitmap= (MY_BITMAP *) arg;
  DBUG_ASSERT(bitmap);
  bitmap_set_bit(bitmap, field->field_index);
  return 0;
}
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bool Item::check_cols(uint c)
{
  if (c != 1)
  {
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    my_error(ER_OPERAND_COLUMNS, MYF(0), c);
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    return 1;
  }
  return 0;
}

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void Item::set_name(const char *str, uint length, CHARSET_INFO *cs)
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{
  if (!length)
  {
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    /* Empty string, used by AS or internal function like last_insert_id() */
    name= (char*) str;
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    name_length= 0;
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    return;
  }
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  if (cs->ctype)
  {
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    const char *str_start= str;

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    /*
      This will probably need a better implementation in the future:
      a function in CHARSET_INFO structure.
    */
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    while (length && !my_isgraph(cs,*str))
    {						// Fix problem with yacc
      length--;
      str++;
    }
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    if (str != str_start && !is_autogenerated_name)
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    {
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      char buff[SAFE_NAME_LEN];
      strmake(buff, str_start,
              min(sizeof(buff)-1, length + (int) (str-str_start)));

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      if (length == 0)
        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_NAME_BECOMES_EMPTY, ER(ER_NAME_BECOMES_EMPTY),
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                            buff);
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      else
        push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_REMOVED_SPACES, ER(ER_REMOVED_SPACES),
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                            buff);
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    }
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  }
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  if (!my_charset_same(cs, system_charset_info))
  {
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    size_t res_length;
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    name= sql_strmake_with_convert(str, name_length= length, cs,
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				   MAX_ALIAS_NAME, system_charset_info,
				   &res_length);
  }
  else
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    name= sql_strmake(str, (name_length= min(length,MAX_ALIAS_NAME)));
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}

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/**
  @details
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  This function is called when:
  - Comparing items in the WHERE clause (when doing where optimization)
  - When trying to find an ORDER BY/GROUP BY item in the SELECT part
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*/

bool Item::eq(const Item *item, bool binary_cmp) const
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{
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  /*
    Note, that this is never TRUE if item is a Item_param:
    for all basic constants we have special checks, and Item_param's
    type() can be only among basic constant types.
  */
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  return type() == item->type() && name && item->name &&
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    !my_strcasecmp(system_charset_info,name,item->name);
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}

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Item *Item::safe_charset_converter(CHARSET_INFO *tocs)
{
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  Item_func_conv_charset *conv= new Item_func_conv_charset(this, tocs, 1);
  return conv->safe ? conv : NULL;
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}


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/**
  @details
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  Created mostly for mysql_prepare_table(). Important
  when a string ENUM/SET column is described with a numeric default value:

  CREATE TABLE t1(a SET('a') DEFAULT 1);

  We cannot use generic Item::safe_charset_converter(), because
  the latter returns a non-fixed Item, so val_str() crashes afterwards.
  Override Item_num method, to return a fixed item.
*/
Item *Item_num::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  char buf[64];
  String *s, tmp(buf, sizeof(buf), &my_charset_bin);
  s= val_str(&tmp);
  if ((conv= new Item_string(s->ptr(), s->length(), s->charset())))
  {
    conv->str_value.copy();
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    conv->str_value.mark_as_const();
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  }
  return conv;
}


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Item *Item_static_float_func::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  char buf[64];
  String *s, tmp(buf, sizeof(buf), &my_charset_bin);
  s= val_str(&tmp);
  if ((conv= new Item_static_string_func(func_name, s->ptr(), s->length(),
                                         s->charset())))
  {
    conv->str_value.copy();
    conv->str_value.mark_as_const();
  }
  return conv;
}


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Item *Item_string::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  uint conv_errors;
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  char *ptr;
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  String tmp, cstr, *ostr= val_str(&tmp);
  cstr.copy(ostr->ptr(), ostr->length(), ostr->charset(), tocs, &conv_errors);
  if (conv_errors || !(conv= new Item_string(cstr.ptr(), cstr.length(),
                                             cstr.charset(),
                                             collation.derivation)))
  {
    /*
      Safe conversion is not possible (or EOM).
      We could not convert a string into the requested character set
      without data loss. The target charset does not cover all the
      characters from the string. Operation cannot be done correctly.
    */
    return NULL;
  }
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  if (!(ptr= current_thd->strmake(cstr.ptr(), cstr.length())))
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    return NULL;
  conv->str_value.set(ptr, cstr.length(), cstr.charset());
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  /* Ensure that no one is going to change the result string */
  conv->str_value.mark_as_const();
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  return conv;
}


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Item *Item_param::safe_charset_converter(CHARSET_INFO *tocs)
{
  if (const_item())
  {
    uint cnv_errors;
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    String *ostr= val_str(&cnvstr);
    cnvitem->str_value.copy(ostr->ptr(), ostr->length(),
                            ostr->charset(), tocs, &cnv_errors);
    if (cnv_errors)
       return NULL;
    cnvitem->str_value.mark_as_const();
    cnvitem->max_length= cnvitem->str_value.numchars() * tocs->mbmaxlen;
    return cnvitem;
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  }
  return NULL;
}


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Item *Item_static_string_func::safe_charset_converter(CHARSET_INFO *tocs)
{
  Item_string *conv;
  uint conv_errors;
  String tmp, cstr, *ostr= val_str(&tmp);
  cstr.copy(ostr->ptr(), ostr->length(), ostr->charset(), tocs, &conv_errors);
  if (conv_errors ||
      !(conv= new Item_static_string_func(func_name,
                                          cstr.ptr(), cstr.length(),
                                          cstr.charset(),
                                          collation.derivation)))
  {
    /*
      Safe conversion is not possible (or EOM).
      We could not convert a string into the requested character set
      without data loss. The target charset does not cover all the
      characters from the string. Operation cannot be done correctly.
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    */
    return NULL;
  }
  conv->str_value.copy();
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  /* Ensure that no one is going to change the result string */
  conv->str_value.mark_as_const();
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  return conv;
}


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bool Item_string::eq(const Item *item, bool binary_cmp) const
{
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  if (type() == item->type() && item->basic_const_item())
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  {
    if (binary_cmp)
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      return !stringcmp(&str_value, &item->str_value);
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    return (collation.collation == item->collation.collation &&
	    !sortcmp(&str_value, &item->str_value, collation.collation));
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  }
  return 0;
}


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/**
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  Get the value of the function as a MYSQL_TIME structure.
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  As a extra convenience the time structure is reset on error!
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*/
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bool Item::get_date(MYSQL_TIME *ltime,uint fuzzydate)
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{
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  if (result_type() == STRING_RESULT)
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  {
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    char buff[40];
    String tmp(buff,sizeof(buff), &my_charset_bin),*res;
    if (!(res=val_str(&tmp)) ||
        str_to_datetime_with_warn(res->ptr(), res->length(),
                                  ltime, fuzzydate) <= MYSQL_TIMESTAMP_ERROR)
      goto err;
  }
  else
  {
    longlong value= val_int();
    int was_cut;
    if (number_to_datetime(value, ltime, fuzzydate, &was_cut) == LL(-1))
    {
      char buff[22], *end;
      end= longlong10_to_str(value, buff, -10);
      make_truncated_value_warning(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                                   buff, (int) (end-buff), MYSQL_TIMESTAMP_NONE,
                                   NullS);
      goto err;
    }
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  }
  return 0;
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err:
  bzero((char*) ltime,sizeof(*ltime));
  return 1;
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}

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/**
  Get time of first argument.\

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  As a extra convenience the time structure is reset on error!
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*/
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bool Item::get_time(MYSQL_TIME *ltime)
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{
  char buff[40];
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  String tmp(buff,sizeof(buff),&my_charset_bin),*res;
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  if (!(res=val_str(&tmp)) ||
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      str_to_time_with_warn(res->ptr(), res->length(), ltime))
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  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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CHARSET_INFO *Item::default_charset()
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{
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  return current_thd->variables.collation_connection;
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}

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/*
  Save value in field, but don't give any warnings

  NOTES
   This is used to temporary store and retrieve a value in a column,
   for example in opt_range to adjust the key value to fit the column.
*/

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int Item::save_in_field_no_warnings(Field *field, bool no_conversions)
{
  int res;
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  TABLE *table= field->table;
  THD *thd= table->in_use;
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  enum_check_fields tmp= thd->count_cuted_fields;
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  my_bitmap_map *old_map= dbug_tmp_use_all_columns(table, table->write_set);
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  ulong sql_mode= thd->variables.sql_mode;
  thd->variables.sql_mode&= ~(MODE_NO_ZERO_IN_DATE | MODE_NO_ZERO_DATE);
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  thd->count_cuted_fields= CHECK_FIELD_IGNORE;
  res= save_in_field(field, no_conversions);
  thd->count_cuted_fields= tmp;
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  dbug_tmp_restore_column_map(table->write_set, old_map);
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  thd->variables.sql_mode= sql_mode;
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  return res;
}


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/*****************************************************************************
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  Item_sp_variable methods
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*****************************************************************************/
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Item_sp_variable::Item_sp_variable(char *sp_var_name_str,
                                   uint sp_var_name_length)
  :m_thd(0)
#ifndef DBUG_OFF
   , m_sp(0)
#endif
{
  m_name.str= sp_var_name_str;
  m_name.length= sp_var_name_length;
}


bool Item_sp_variable::fix_fields(THD *thd, Item **)
{
  Item *it;

  m_thd= thd; /* NOTE: this must be set before any this_xxx() */
  it= this_item();

  DBUG_ASSERT(it->fixed);

  max_length= it->max_length;
  decimals= it->decimals;
  unsigned_flag= it->unsigned_flag;
  fixed= 1;
  collation.set(it->collation.collation, it->collation.derivation);

  return FALSE;
}


double Item_sp_variable::val_real()
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
  double ret= it->val_real();
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  null_value= it->null_value;
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  return ret;
}


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longlong Item_sp_variable::val_int()
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
  longlong ret= it->val_int();
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  null_value= it->null_value;
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  return ret;
}


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String *Item_sp_variable::val_str(String *sp)
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
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  String *res= it->val_str(sp);
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  null_value= it->null_value;
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  if (!res)
    return NULL;

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  /*
    This way we mark returned value of val_str as const,
    so that various functions (e.g. CONCAT) won't try to
    modify the value of the Item. Analogous mechanism is
    implemented for Item_param.
    Without this trick Item_splocal could be changed as a
    side-effect of expression computation. Here is an example
    of what happens without it: suppose x is varchar local
    variable in a SP with initial value 'ab' Then
      select concat(x,'c');
    would change x's value to 'abc', as Item_func_concat::val_str()
    would use x's internal buffer to compute the result.
    This is intended behaviour of Item_func_concat. Comments to
    Item_param class contain some more details on the topic.
  */
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  if (res != &str_value)
    str_value.set(res->ptr(), res->length(), res->charset());
  else
    res->mark_as_const();
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  return &str_value;
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}


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my_decimal *Item_sp_variable::val_decimal(my_decimal *decimal_value)
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{
  DBUG_ASSERT(fixed);
  Item *it= this_item();
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  my_decimal *val= it->val_decimal(decimal_value);
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  null_value= it->null_value;
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  return val;
}


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bool Item_sp_variable::is_null()
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{
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  return this_item()->is_null();
}


/*****************************************************************************
  Item_splocal methods
*****************************************************************************/

Item_splocal::Item_splocal(const LEX_STRING &sp_var_name,
                           uint sp_var_idx,
                           enum_field_types sp_var_type,
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                           uint pos_in_q, uint len_in_q)
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  :Item_sp_variable(sp_var_name.str, sp_var_name.length),
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   m_var_idx(sp_var_idx), pos_in_query(pos_in_q), len_in_query(len_in_q)
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{
  maybe_null= TRUE;

  m_type= sp_map_item_type(sp_var_type);
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  m_field_type= sp_var_type;
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  m_result_type= sp_map_result_type(sp_var_type);
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}


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Item *
Item_splocal::this_item()
{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_item(m_var_idx);
}

const Item *
Item_splocal::this_item() const
{
  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_item(m_var_idx);
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}

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Item **
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Item_splocal::this_item_addr(THD *thd, Item **)
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{
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  DBUG_ASSERT(m_sp == thd->spcont->sp);

  return thd->spcont->get_item_addr(m_var_idx);
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}

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void Item_splocal::print(String *str, enum_query_type)
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{
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  str->reserve(m_name.length+8);
  str->append(m_name.str, m_name.length);
  str->append('@');
  str->qs_append(m_var_idx);
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}

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bool Item_splocal::set_value(THD *thd, sp_rcontext *ctx, Item **it)
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{
  return ctx->set_variable(thd, get_var_idx(), it);
}


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/*****************************************************************************
  Item_case_expr methods
*****************************************************************************/

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Item_case_expr::Item_case_expr(uint case_expr_id)
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  :Item_sp_variable( C_STRING_WITH_LEN("case_expr")),
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   m_case_expr_id(case_expr_id)
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{
}


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Item *
Item_case_expr::this_item()
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{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_case_expr(m_case_expr_id);
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}


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const Item *
Item_case_expr::this_item() const
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{
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  DBUG_ASSERT(m_sp == m_thd->spcont->sp);

  return m_thd->spcont->get_case_expr(m_case_expr_id);
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}


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Item **
Item_case_expr::this_item_addr(THD *thd, Item **)
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{
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  DBUG_ASSERT(m_sp == thd->spcont->sp);

  return thd->spcont->get_case_expr_addr(m_case_expr_id);
}


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void Item_case_expr::print(String *str, enum_query_type)
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{
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  if (str->reserve(MAX_INT_WIDTH + sizeof("case_expr@")))
    return;                                    /* purecov: inspected */
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  VOID(str->append(STRING_WITH_LEN("case_expr@")));
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  str->qs_append(m_case_expr_id);
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}


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/*****************************************************************************
  Item_name_const methods
*****************************************************************************/
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double Item_name_const::val_real()
{
  DBUG_ASSERT(fixed);
  double ret= value_item->val_real();
  null_value= value_item->null_value;
  return ret;
}


longlong Item_name_const::val_int()
{
  DBUG_ASSERT(fixed);
  longlong ret= value_item->val_int();
  null_value= value_item->null_value;
  return ret;
}


String *Item_name_const::val_str(String *sp)
{
  DBUG_ASSERT(fixed);
  String *ret= value_item->val_str(sp);
  null_value= value_item->null_value;
  return ret;
}


my_decimal *Item_name_const::val_decimal(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed);
  my_decimal *val= value_item->val_decimal(decimal_value);
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  null_value= value_item->null_value;
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  return val;
}


bool Item_name_const::is_null()
{
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  return value_item->is_null();
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}

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Item_name_const::Item_name_const(Item *name_arg, Item *val):
    value_item(val), name_item(name_arg)
{
  if (!(valid_args= name_item->basic_const_item() &&
                    (value_item->basic_const_item() ||
                     ((value_item->type() == FUNC_ITEM) &&
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                      ((((Item_func *) value_item)->functype() ==
                         Item_func::COLLATE_FUNC) ||
                      ((((Item_func *) value_item)->functype() ==
                         Item_func::NEG_FUNC) &&
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                      (((Item_func *) value_item)->key_item()->type() !=
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                         FUNC_ITEM)))))))
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    my_error(ER_WRONG_ARGUMENTS, MYF(0), "NAME_CONST");
  Item::maybe_null= TRUE;
}


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Item::Type Item_name_const::type() const
{
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  /*
    As 
    1. one can try to create the Item_name_const passing non-constant 
    arguments, although it's incorrect and 
    2. the type() method can be called before the fix_fields() to get
    type information for a further type cast, e.g. 
    if (item->type() == FIELD_ITEM) 
      ((Item_field *) item)->... 
    we return NULL_ITEM in the case to avoid wrong casting.
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    valid_args guarantees value_item->basic_const_item(); if type is
    FUNC_ITEM, then we have a fudged item_func_neg() on our hands
    and return the underlying type.
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    For Item_func_set_collation()
    e.g. NAME_CONST('name', 'value' COLLATE collation) we return its
    'value' argument type. 
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  */
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  if (!valid_args)
    return NULL_ITEM;
  Item::Type value_type= value_item->type();
  if (value_type == FUNC_ITEM)
  {
    /* 
      The second argument of NAME_CONST('name', 'value') must be 
      a simple constant item or a NEG_FUNC/COLLATE_FUNC.
    */
    DBUG_ASSERT(((Item_func *) value_item)->functype() == 
                Item_func::NEG_FUNC ||
                ((Item_func *) value_item)->functype() == 
                Item_func::COLLATE_FUNC);
    return ((Item_func *) value_item)->key_item()->type();            
  }
  return value_type;
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}


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bool Item_name_const::fix_fields(THD *thd, Item **ref)
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{
  char buf[128];
  String *item_name;
  String s(buf, sizeof(buf), &my_charset_bin);
  s.length(0);

  if (value_item->fix_fields(thd, &value_item) ||
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      name_item->fix_fields(thd, &name_item) ||
      !value_item->const_item() ||
      !name_item->const_item() ||
      !(item_name= name_item->val_str(&s))) // Can't have a NULL name 
  {
    my_error(ER_RESERVED_SYNTAX, MYF(0), "NAME_CONST");
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    return TRUE;
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  }
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  if (is_autogenerated_name)
  {
    set_name(item_name->ptr(), (uint) item_name->length(), system_charset_info);
  }
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  collation.set(value_item->collation.collation, DERIVATION_IMPLICIT);
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  max_length= value_item->max_length;
  decimals= value_item->decimals;
  fixed= 1;
  return FALSE;
}


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void Item_name_const::print(String *str, enum_query_type query_type)
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{
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  str->append(STRING_WITH_LEN("NAME_CONST("));
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  name_item->print(str, query_type);
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  str->append(',');
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  value_item->print(str, query_type);
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  str->append(')');
}

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/*
 need a special class to adjust printing : references to aggregate functions 
 must not be printed as refs because the aggregate functions that are added to
 the front of select list are not printed as well.
*/
class Item_aggregate_ref : public Item_ref
{
public:
  Item_aggregate_ref(Name_resolution_context *context_arg, Item **item,
                  const char *table_name_arg, const char *field_name_arg)
    :Item_ref(context_arg, item, table_name_arg, field_name_arg) {}

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  virtual inline void print (String *str, enum_query_type query_type)
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  {
    if (ref)
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      (*ref)->print(str, query_type);
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    else
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      Item_ident::print(str, query_type);
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  }
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  virtual Ref_Type ref_type() { return AGGREGATE_REF; }
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};


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/**
  Move SUM items out from item tree and replace with reference.
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  @param thd			Thread handler
  @param ref_pointer_array	Pointer to array of reference fields
  @param fields		All fields in select
  @param ref			Pointer to item
  @param skip_registered       <=> function be must skipped for registered
                               SUM items
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  @note
    This is from split_sum_func2() for items that should be split
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    All found SUM items are added FIRST in the fields list and
    we replace the item with a reference.
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    thd->fatal_error() may be called if we are out of memory
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*/

void Item::split_sum_func2(THD *thd, Item **ref_pointer_array,
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                           List<Item> &fields, Item **ref, 
                           bool skip_registered)
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{
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  /* An item of type Item_sum  is registered <=> ref_by != 0 */ 
  if (type() == SUM_FUNC_ITEM && skip_registered && 
      ((Item_sum *) this)->ref_by)
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    return;
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  if ((type() != SUM_FUNC_ITEM && with_sum_func) ||
      (type() == FUNC_ITEM &&
       (((Item_func *) this)->functype() == Item_func::ISNOTNULLTEST_FUNC ||
        ((Item_func *) this)->functype() == Item_func::TRIG_COND_FUNC)))
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  {
    /* Will split complicated items and ignore simple ones */
    split_sum_func(thd, ref_pointer_array, fields);
  }
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  else if ((type() == SUM_FUNC_ITEM || (used_tables() & ~PARAM_TABLE_BIT)) &&
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           type() != SUBSELECT_ITEM &&
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           (type() != REF_ITEM ||
           ((Item_ref*)this)->ref_type() == Item_ref::VIEW_REF))
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  {
    /*
      Replace item with a reference so that we can easily calculate
      it (in case of sum functions) or copy it (in case of fields)

      The test above is to ensure we don't do a reference for things
      that are constants (PARAM_TABLE_BIT is in effect a constant)
      or already referenced (for example an item in HAVING)
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      Exception is Item_direct_view_ref which we need to convert to
      Item_ref to allow fields from view being stored in tmp table.
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    */
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    Item_aggregate_ref *item_ref;
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    uint el= fields.elements;
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    /*
      If this is an item_ref, get the original item
      This is a safety measure if this is called for things that is
      already a reference.
    */
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    Item *real_itm= real_item();
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    ref_pointer_array[el]= real_itm;
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    if (!(item_ref= new Item_aggregate_ref(&thd->lex->current_select->context,
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                                           ref_pointer_array + el, 0, name)))
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      return;                                   // fatal_error is set
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    if (type() == SUM_FUNC_ITEM)
      item_ref->depended_from= ((Item_sum *) this)->depended_from(); 
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    fields.push_front(real_itm);
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    thd->change_item_tree(ref, item_ref);
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  }
}


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static bool
left_is_superset(DTCollation *left, DTCollation *right)
{
  /* Allow convert to Unicode */
  if (left->collation->state & MY_CS_UNICODE &&
      (left->derivation < right->derivation ||
       (left->derivation == right->derivation &&
        !(right->collation->state & MY_CS_UNICODE))))
    return TRUE;
  /* Allow convert from ASCII */
  if (right->repertoire == MY_REPERTOIRE_ASCII &&
      (left->derivation < right->derivation ||
       (left->derivation == right->derivation &&
        !(left->repertoire == MY_REPERTOIRE_ASCII))))
    return TRUE;
  /* Disallow conversion otherwise */
  return FALSE;
}

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/**
  Aggregate two collations together taking
  into account their coercibility (aka derivation):.

  0 == DERIVATION_EXPLICIT  - an explicitly written COLLATE clause @n
  1 == DERIVATION_NONE      - a mix of two different collations @n
  2 == DERIVATION_IMPLICIT  - a column @n
  3 == DERIVATION_COERCIBLE - a string constant.

  The most important rules are:
  -# If collations are the same:
  chose this collation, and the strongest derivation.
  -# If collations are different:
  - Character sets may differ, but only if conversion without
  data loss is possible. The caller provides flags whether
  character set conversion attempts should be done. If no
  flags are substituted, then the character sets must be the same.
  Currently processed flags are:
  MY_COLL_ALLOW_SUPERSET_CONV  - allow conversion to a superset
  MY_COLL_ALLOW_COERCIBLE_CONV - allow conversion of a coercible value
  - two EXPLICIT collations produce an error, e.g. this is wrong:
  CONCAT(expr1 collate latin1_swedish_ci, expr2 collate latin1_german_ci)
  - the side with smaller derivation value wins,
  i.e. a column is stronger than a string constant,
  an explicit COLLATE clause is stronger than a column.
  - if derivations are the same, we have DERIVATION_NONE,
  we'll wait for an explicit COLLATE clause which possibly can
  come from another argument later: for example, this is valid,
  but we don't know yet when collecting the first two arguments:
     @code
       CONCAT(latin1_swedish_ci_column,
              latin1_german1_ci_column,
              expr COLLATE latin1_german2_ci)
  @endcode
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*/
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bool DTCollation::aggregate(DTCollation &dt, uint flags)
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{
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  if (!my_charset_same(collation, dt.collation))
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  {
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    /* 
       We do allow to use binary strings (like BLOBS)
       together with character strings.
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       Binaries have more precedence than a character
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       string of the same derivation.
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    */
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    if (collation == &my_charset_bin)
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    {
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      if (derivation <= dt.derivation)
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      {
	/* Do nothing */
      }
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      else
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      {
	set(dt); 
      }
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    }
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    else if (dt.collation == &my_charset_bin)
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    {
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      if (dt.derivation <= derivation)
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      {
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        set(dt);
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      }
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    }
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    else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&
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             left_is_superset(this, &dt))
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    {
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      /* Do nothing */
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    }
    else if ((flags & MY_COLL_ALLOW_SUPERSET_CONV) &&
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             left_is_superset(&dt, this))
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    {
      set(dt);
    }
    else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&
             derivation < dt.derivation &&
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             dt.derivation >= DERIVATION_SYSCONST)
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    {
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      /* Do nothing */
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    }
    else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&
             dt.derivation < derivation &&
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             derivation >= DERIVATION_SYSCONST)
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    {
      set(dt);
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    }
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    else
    {
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      // Cannot apply conversion
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      set(&my_charset_bin, DERIVATION_NONE,
          (dt.repertoire|repertoire));
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      return 1;
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    }
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  }
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  else if (derivation < dt.derivation)
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  {
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    /* Do nothing */
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  }
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  else if (dt.derivation < derivation)
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  {
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    set(dt);
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  }
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  else
  { 
    if (collation == dt.collation)
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    {
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      /* Do nothing */
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    }
    else 
    {
      if (derivation == DERIVATION_EXPLICIT)
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      {
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        set(0, DERIVATION_NONE, 0);
        return 1;
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      }
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      if (collation->state & MY_CS_BINSORT)
        return 0;
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      if (dt.collation->state & MY_CS_BINSORT)
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      {
        set(dt);
        return 0;
      }
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      CHARSET_INFO *bin= get_charset_by_csname(collation->csname, 
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                                               MY_CS_BINSORT,MYF(0));
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      set(bin, DERIVATION_NONE);
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    }
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  }
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  repertoire|= dt.repertoire;
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  return 0;
}

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/******************************/
static
void my_coll_agg_error(DTCollation &c1, DTCollation &c2, const char *fname)
{
  my_error(ER_CANT_AGGREGATE_2COLLATIONS,MYF(0),
           c1.collation->name,c1.derivation_name(),
           c2.collation->name,c2.derivation_name(),
           fname);
}


static
void my_coll_agg_error(DTCollation &c1, DTCollation &c2, DTCollation &c3,
                       const char *fname)
{
  my_error(ER_CANT_AGGREGATE_3COLLATIONS,MYF(0),
  	   c1.collation->name,c1.derivation_name(),
	   c2.collation->name,c2.derivation_name(),
	   c3.collation->name,c3.derivation_name(),
	   fname);
}


static
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void my_coll_agg_error(Item** args, uint count, const char *fname,
                       int item_sep)
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{
  if (count == 2)
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    my_coll_agg_error(args[0]->collation, args[item_sep]->collation, fname);
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  else if (count == 3)
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    my_coll_agg_error(args[0]->collation, args[item_sep]->collation,
                      args[2*item_sep]->collation, fname);
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  else
    my_error(ER_CANT_AGGREGATE_NCOLLATIONS,MYF(0),fname);
}


bool agg_item_collations(DTCollation &c, const char *fname,
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                         Item **av, uint count, uint flags, int item_sep)
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{
  uint i;
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  Item **arg;
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  bool unknown_cs= 0;

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  c.set(av[0]->collation);
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  for (i= 1, arg= &av[item_sep]; i < count; i++, arg++)
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  {
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    if (c.aggregate((*arg)->collation, flags))
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    {
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      if (c.derivation == DERIVATION_NONE &&
          c.collation == &my_charset_bin)
      {
        unknown_cs= 1;
        continue;
      }
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      my_coll_agg_error(av, count, fname, item_sep);
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      return TRUE;
    }
  }
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  if (unknown_cs &&
      c.derivation != DERIVATION_EXPLICIT)
  {
    my_coll_agg_error(av, count, fname, item_sep);
    return TRUE;
  }

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  if ((flags & MY_COLL_DISALLOW_NONE) &&
      c.derivation == DERIVATION_NONE)
  {
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    my_coll_agg_error(av, count, fname, item_sep);
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    return TRUE;
  }
  return FALSE;
}


bool agg_item_collations_for_comparison(DTCollation &c, const char *fname,
                                        Item **av, uint count, uint flags)
{
  return (agg_item_collations(c, fname, av, count,
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                              flags | MY_COLL_DISALLOW_NONE, 1));
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}


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bool agg_item_set_converter(DTCollation &coll, const char *fname,
                            Item **args, uint nargs, uint flags, int item_sep)
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{
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  Item **arg, *safe_args[2]= {NULL, NULL};
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  /*
    For better error reporting: save the first and the second argument.
    We need this only if the the number of args is 3 or 2:
    - for a longer argument list, "Illegal mix of collations"
      doesn't display each argument's characteristics.
    - if nargs is 1, then this error cannot happen.
  */
  if (nargs >=2 && nargs <= 3)
  {
    safe_args[0]= args[0];
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    safe_args[1]= args[item_sep];
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  }

  THD *thd= current_thd;
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  Query_arena *arena, backup;
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  bool res= FALSE;
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  uint i;
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  /*
    In case we're in statement prepare, create conversion item
    in its memory: it will be reused on each execute.
  */
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  arena= thd->is_stmt_prepare() ? thd->activate_stmt_arena_if_needed(&backup)
                                : NULL;
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  for (i= 0, arg= args; i < nargs; i++, arg+= item_sep)
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  {
    Item* conv;
    uint32 dummy_offset;
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    if (!String::needs_conversion(0, (*arg)->collation.collation,
                                  coll.collation,
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                                  &dummy_offset))
      continue;

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    if (!(conv= (*arg)->safe_charset_converter(coll.collation)) &&
        ((*arg)->collation.repertoire == MY_REPERTOIRE_ASCII))
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      conv= new Item_func_conv_charset(*arg, coll.collation, 1);
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    if (!conv)
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    {
      if (nargs >=2 && nargs <= 3)
      {
        /* restore the original arguments for better error message */
        args[0]= safe_args[0];
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        args[item_sep]= safe_args[1];
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      }
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      my_coll_agg_error(args, nargs, fname, item_sep);
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      res= TRUE;
      break; // we cannot return here, we need to restore "arena".
    }
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    if ((*arg)->type() == Item::FIELD_ITEM)
      ((Item_field *)(*arg))->no_const_subst= 1;
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    /*
      If in statement prepare, then we create a converter for two
      constant items, do it once and then reuse it.
      If we're in execution of a prepared statement, arena is NULL,
      and the conv was created in runtime memory. This can be
      the case only if the argument is a parameter marker ('?'),
      because for all true constants the charset converter has already
      been created in prepare. In this case register the change for
      rollback.
    */
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    if (thd->is_stmt_prepare())
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      *arg= conv;
    else
      thd->change_item_tree(arg, conv);
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    /*
      We do not check conv->fixed, because Item_func_conv_charset which can
      be return by safe_charset_converter can't be fixed at creation
    */
    conv->fix_fields(thd, arg);
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  }
  if (arena)
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    thd->restore_active_arena(arena, &backup);
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  return res;
}


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/* 
  Collect arguments' character sets together.
  We allow to apply automatic character set conversion in some cases.
  The conditions when conversion is possible are:
  - arguments A and B have different charsets
  - A wins according to coercibility rules
    (i.e. a column is stronger than a string constant,
     an explicit COLLATE clause is stronger than a column)
  - character set of A is either superset for character set of B,
    or B is a string constant which can be converted into the
    character set of A without data loss.
    
  If all of the above is true, then it's possible to convert
  B into the character set of A, and then compare according
  to the collation of A.
  
  For functions with more than two arguments:

    collect(A,B,C) ::= collect(collect(A,B),C)

  Since this function calls THD::change_item_tree() on the passed Item **
  pointers, it is necessary to pass the original Item **'s, not copies.
  Otherwise their values will not be properly restored (see BUG#20769).
  If the items are not consecutive (eg. args[2] and args[5]), use the
  item_sep argument, ie.

    agg_item_charsets(coll, fname, &args[2], 2, flags, 3)

*/

bool agg_item_charsets(DTCollation &coll, const char *fname,
                       Item **args, uint nargs, uint flags, int item_sep)
{
  if (agg_item_collations(coll, fname, args, nargs, flags, item_sep))
    return TRUE;

  return agg_item_set_converter(coll, fname, args, nargs, flags, item_sep);
}


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void Item_ident_for_show::make_field(Send_field *tmp_field)
{
  tmp_field->table_name= tmp_field->org_table_name= table_name;
  tmp_field->db_name= db_name;
  tmp_field->col_name= tmp_field->org_col_name= field->field_name;
  tmp_field->charsetnr= field->charset()->number;
  tmp_field->length=field->field_length;
  tmp_field->type=field->type();
  tmp_field->flags= field->table->maybe_null ? 
    (field->flags & ~NOT_NULL_FLAG) : field->flags;
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  tmp_field->decimals= field->decimals();
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}
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/**********************************************/

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Item_field::Item_field(Field *f)
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  :Item_ident(0, NullS, *f->table_name, f->field_name),
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   item_equal(0), no_const_subst(0),
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   have_privileges(0), any_privileges(0)
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{
  set_field(f);
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  /*
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    field_name and table_name should not point to garbage
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    if this item is to be reused
  */
  orig_table_name= orig_field_name= "";
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  with_field= 1;
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}

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/**
  Constructor used inside setup_wild().

  Ensures that field, table, and database names will live as long as
  Item_field (this is important in prepared statements).
*/

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Item_field::Item_field(THD *thd, Name_resolution_context *context_arg,
                       Field *f)
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  :Item_ident(context_arg, f->table->s->db.str, *f->table_name, f->field_name),
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   item_equal(0), no_const_subst(0),
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   have_privileges(0), any_privileges(0)
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{
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  /*
    We always need to provide Item_field with a fully qualified field
    name to avoid ambiguity when executing prepared statements like
    SELECT * from d1.t1, d2.t1; (assuming d1.t1 and d2.t1 have columns
    with same names).
    This is because prepared statements never deal with wildcards in
    select list ('*') and always fix fields using fully specified path
    (i.e. db.table.column).
    No check for OOM: if db_name is NULL, we'll just get
    "Field not found" error.
    We need to copy db_name, table_name and field_name because they must
    be allocated in the statement memory, not in table memory (the table
    structure can go away and pop up again between subsequent executions
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    of a prepared statement or after the close_tables_for_reopen() call
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    in mysql_multi_update_prepare() or due to wildcard expansion in stored
    procedures).
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  */
  {
    if (db_name)
      orig_db_name= thd->strdup(db_name);
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    if (table_name)
      orig_table_name= thd->strdup(table_name);
    if (field_name)
      orig_field_name= thd->strdup(field_name);
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    /*
      We don't restore 'name' in cleanup because it's not changed
      during execution. Still we need it to point to persistent
      memory if this item is to be reused.
    */
    name= (char*) orig_field_name;
  }
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  set_field(f);
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  with_field= 1;
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}

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Item_field::Item_field(Name_resolution_context *context_arg,
                       const char *db_arg,const char *table_name_arg,
                       const char *field_name_arg)
  :Item_ident(context_arg, db_arg,table_name_arg,field_name_arg),
   field(0), result_field(0), item_equal(0), no_const_subst(0),
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   have_privileges(0), any_privileges(0)
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{
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  SELECT_LEX *select= current_thd->lex->current_select;
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  collation.set(DERIVATION_IMPLICIT);
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  if (select && select->parsing_place != IN_HAVING)
      select->select_n_where_fields++;
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  with_field= 1;
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}

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/**
  Constructor need to process subselect with temporary tables (see Item)
*/

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Item_field::Item_field(THD *thd, Item_field *item)
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  :Item_ident(thd, item),
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   field(item->field),
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   result_field(item->result_field),
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   item_equal(item->item_equal),
   no_const_subst(item->no_const_subst),
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   have_privileges(item->have_privileges),
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   any_privileges(item->any_privileges)
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{
  collation.set(DERIVATION_IMPLICIT);
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  with_field= 1;
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}
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void Item_field::set_field(Field *field_par)
{
  field=result_field=field_par;			// for easy coding with fields
  maybe_null=field->maybe_null();
  decimals= field->decimals();
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  max_length= field_par->max_display_length();
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  table_name= *field_par->table_name;
  field_name= field_par->field_name;
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  db_name= field_par->table->s->db.str;
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  alias_name_used= field_par->table->alias_name_used;
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  unsigned_flag=test(field_par->flags & UNSIGNED_FLAG);
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  collation.set(field_par->charset(), field_par->derivation());
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  fixed= 1;
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  if (field->table->s->tmp_table == SYSTEM_TMP_TABLE)
    any_privileges= 0;
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}


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/**
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  Reset this item to point to a field from the new temporary table.
  This is used when we create a new temporary table for each execution
  of prepared statement.
*/

void Item_field::reset_field(Field *f)
{
  set_field(f);
  /* 'name' is pointing at field->field_name of old field */
  name= (char*) f->field_name;
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}

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bool Item_field::enumerate_field_refs_processor(uchar *arg)
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{
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  Field_enumerator *fe= (Field_enumerator*)arg;
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  fe->visit_field(this);
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  return FALSE;
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}

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const char *Item_ident::full_name() const
{
  char *tmp;
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  if (!table_name || !field_name)
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    return field_name ? field_name : name ? name : "tmp_field";
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  if (db_name && db_name[0])
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  {
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    tmp=(char*) sql_alloc((uint) strlen(db_name)+(uint) strlen(table_name)+
			  (uint) strlen(field_name)+3);
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    strxmov(tmp,db_name,".",table_name,".",field_name,NullS);
  }
  else
  {
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    if (table_name[0])
    {
      tmp= (char*) sql_alloc((uint) strlen(table_name) +
			     (uint) strlen(field_name) + 2);
      strxmov(tmp, table_name, ".", field_name, NullS);
    }
    else
      tmp= (char*) field_name;
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  }
  return tmp;
}

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void Item_ident::print(String *str, enum_query_type query_type)
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{
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  THD *thd= current_thd;
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  char d_name_buff[MAX_ALIAS_NAME], t_name_buff[MAX_ALIAS_NAME];
  const char *d_name= db_name, *t_name= table_name;
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  if (lower_case_table_names== 1 ||
      (lower_case_table_names == 2 && !alias_name_used))
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  {
    if (table_name && table_name[0])
    {
      strmov(t_name_buff, table_name);
      my_casedn_str(files_charset_info, t_name_buff);
      t_name= t_name_buff;
    }
    if (db_name && db_name[0])
    {
      strmov(d_name_buff, db_name);
      my_casedn_str(files_charset_info, d_name_buff);
      d_name= d_name_buff;
    }
  }

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  if (!table_name || !field_name || !field_name[0])
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  {
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    const char *nm= (field_name && field_name[0]) ?
                      field_name : name ? name : "tmp_field";
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    append_identifier(thd, str, nm, (uint) strlen(nm));
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    return;
  }
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  if (db_name && db_name[0] && !alias_name_used)
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  {
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    if (!(cached_table && cached_table->belong_to_view &&
          cached_table->belong_to_view->compact_view_format))
    {
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      append_identifier(thd, str, d_name, (uint)strlen(d_name));
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      str->append('.');
    }
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    append_identifier(thd, str, t_name, (uint)strlen(t_name));
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    str->append('.');
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    append_identifier(thd, str, field_name, (uint)strlen(field_name));
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  }
  else
  {
    if (table_name[0])
    {
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      append_identifier(thd, str, t_name, (uint) strlen(t_name));
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      str->append('.');
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      append_identifier(thd, str, field_name, (uint) strlen(field_name));
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    }
    else
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      append_identifier(thd, str, field_name, (uint) strlen(field_name));
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  }
}

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/* ARGSUSED */
String *Item_field::val_str(String *str)
{
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  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0;
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  str->set_charset(str_value.charset());
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  return field->val_str(str,&str_value);
}

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double Item_field::val_real()
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{
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  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0.0;
  return field->val_real();
}

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longlong Item_field::val_int()
{
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  DBUG_ASSERT(fixed == 1);
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  if ((null_value=field->is_null()))
    return 0;
  return field->val_int();
}


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my_decimal *Item_field::val_decimal(my_decimal *decimal_value)
{
  if ((null_value= field->is_null()))
    return 0;
  return field->val_decimal(decimal_value);
}


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String *Item_field::str_result(String *str)
{
  if ((null_value=result_field->is_null()))
    return 0;
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  str->set_charset(str_value.charset());
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  return result_field->val_str(str,&str_value);
}

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bool Item_field::get_date(MYSQL_TIME *ltime,uint fuzzydate)
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{
  if ((null_value=field->is_null()) || field->get_date(ltime,fuzzydate))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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bool Item_field::get_date_result(MYSQL_TIME *ltime,uint fuzzydate)
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{
  if ((null_value=result_field->is_null()) ||
      result_field->get_date(ltime,fuzzydate))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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bool Item_field::get_time(MYSQL_TIME *ltime)
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{
  if ((null_value=field->is_null()) || field->get_time(ltime))
  {
    bzero((char*) ltime,sizeof(*ltime));
    return 1;
  }
  return 0;
}

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void Item_field::save_result(Field *to)
{
  save_field_in_field(result_field, &null_value, to, TRUE);
}


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double Item_field::val_result()
{
  if ((null_value=result_field->is_null()))
    return 0.0;
  return result_field->val_real();
}

longlong Item_field::val_int_result()
{
  if ((null_value=result_field->is_null()))
    return 0;
  return result_field->val_int();
}

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my_decimal *Item_field::val_decimal_result(my_decimal *decimal_value)
{
  if ((null_value= result_field->is_null()))
    return 0;
  return result_field->val_decimal(decimal_value);
}


bool Item_field::val_bool_result()
{
  if ((null_value= result_field->is_null()))
    return FALSE;
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  switch (result_field->result_type()) {
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  case INT_RESULT:
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    return result_field->val_int() != 0;
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  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *val= result_field->val_decimal(&decimal_value);
    if (val)
      return !my_decimal_is_zero(val);
    return 0;
  }
  case REAL_RESULT:
  case STRING_RESULT:
    return result_field->val_real() != 0.0;
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
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    return 0;                                   // Shut up compiler
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  }
}


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bool Item_field::is_null_result()
{
  return (null_value=result_field->is_null());
}


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bool Item_field::eq(const Item *item, bool binary_cmp) const
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{
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  Item *real_item= ((Item *) item)->real_item();
  if (real_item->type() != FIELD_ITEM)
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    return 0;
  
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  Item_field *item_field= (Item_field*) real_item;
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  if (item_field->field && field)
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    return item_field->field == field;
  /*
    We may come here when we are trying to find a function in a GROUP BY
    clause from the select list.
    In this case the '100 % correct' way to do this would be to first
    run fix_fields() on the GROUP BY item and then retry this function, but
    I think it's better to relax the checking a bit as we will in
    most cases do the correct thing by just checking the field name.
    (In cases where we would choose wrong we would have to generate a
    ER_NON_UNIQ_ERROR).
  */
  return (!my_strcasecmp(system_charset_info, item_field->name,
			 field_name) &&
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	  (!item_field->table_name || !table_name ||
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	   (!my_strcasecmp(table_alias_charset, item_field->table_name,
			   table_name) &&
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	    (!item_field->db_name || !db_name ||
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	     (item_field->db_name && !strcmp(item_field->db_name,
					     db_name))))));
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}

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table_map Item_field::used_tables() const
{
  if (field->table->const_table)
    return 0;					// const item
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  return (depended_from ? OUTER_REF_TABLE_BIT : field->table->map);
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}

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void Item_field::fix_after_pullout(st_select_lex *new_parent, Item **ref)
{
  if (new_parent == depended_from)
    depended_from= NULL;
  Name_resolution_context *ctx= new Name_resolution_context();
  ctx->outer_context= NULL; // We don't build a complete name resolver
  ctx->table_list= NULL;    // We rely on first_name_resolution_table instead
  ctx->select_lex= new_parent;
  ctx->first_name_resolution_table= context->first_name_resolution_table;
  ctx->last_name_resolution_table=  context->last_name_resolution_table;
  ctx->error_processor=             context->error_processor;
  ctx->error_processor_data=        context->error_processor_data;
  ctx->resolve_in_select_list=      context->resolve_in_select_list;
  ctx->security_ctx=                context->security_ctx;
  this->context=ctx;
}


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Item *Item_field::get_tmp_table_item(THD *thd)
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{
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  Item_field *new_item= new Item_field(thd, this);
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  if (new_item)
    new_item->field= new_item->result_field;
  return new_item;
}
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longlong Item_field::val_int_endpoint(bool left_endp, bool *incl_endp)
{
  longlong res= val_int();
  return null_value? LONGLONG_MIN : res;
}
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/**
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  Create an item from a string we KNOW points to a valid longlong
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  end \\0 terminated number string.
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  This is always 'signed'. Unsigned values are created with Item_uint()
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*/

Item_int::Item_int(const char *str_arg, uint length)
{
  char *end_ptr= (char*) str_arg + length;
  int error;
  value= my_strtoll10(str_arg, &end_ptr, &error);
  max_length= (uint) (end_ptr - str_arg);
  name= (char*) str_arg;
  fixed= 1;
}


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my_decimal *Item_int::val_decimal(my_decimal *decimal_value)
{
  int2my_decimal(E_DEC_FATAL_ERROR, value, unsigned_flag, decimal_value);
  return decimal_value;
}

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String *Item_int::val_str(String *str)
{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set_int(value, unsigned_flag, &my_charset_bin);
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  return str;
}

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void Item_int::print(String *str, enum_query_type query_type)
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{
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  // my_charset_bin is good enough for numbers
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  str_value.set_int(value, unsigned_flag, &my_charset_bin);
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  str->append(str_value);
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}

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Item_uint::Item_uint(const char *str_arg, uint length):
  Item_int(str_arg, length)
{
  unsigned_flag= 1;
}


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Item_uint::Item_uint(const char *str_arg, longlong i, uint length):
  Item_int(str_arg, i, length)
{
  unsigned_flag= 1;
}


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String *Item_uint::val_str(String *str)
{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set((ulonglong) value, &my_charset_bin);
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  return str;
}

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void Item_uint::print(String *str, enum_query_type query_type)
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{
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  // latin1 is good enough for numbers
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  str_value.set((ulonglong) value, default_charset());
  str->append(str_value);
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}

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Item_decimal::Item_decimal(const char *str_arg, uint length,
                           CHARSET_INFO *charset)
{
  str2my_decimal(E_DEC_FATAL_ERROR, str_arg, length, charset, &decimal_value);
  name= (char*) str_arg;
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length_no_truncation(decimal_value.intg +
                                                           decimals,
                                                           decimals,
                                                           unsigned_flag);
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}

Item_decimal::Item_decimal(longlong val, bool unsig)
{
  int2my_decimal(E_DEC_FATAL_ERROR, val, unsig, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length_no_truncation(decimal_value.intg +
                                                           decimals,
                                                           decimals,
                                                           unsigned_flag);
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}


Item_decimal::Item_decimal(double val, int precision, int scale)
{
  double2my_decimal(E_DEC_FATAL_ERROR, val, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length_no_truncation(decimal_value.intg +
                                                           decimals,
                                                           decimals,
                                                           unsigned_flag);
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}


Item_decimal::Item_decimal(const char *str, const my_decimal *val_arg,
                           uint decimal_par, uint length)
{
  my_decimal2decimal(val_arg, &decimal_value);
  name= (char*) str;
  decimals= (uint8) decimal_par;
  max_length= length;
  fixed= 1;
}


Item_decimal::Item_decimal(my_decimal *value_par)
{
  my_decimal2decimal(value_par, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length_no_truncation(decimal_value.intg +
                                                           decimals,
                                                           decimals,
                                                           unsigned_flag);
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}


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Item_decimal::Item_decimal(const uchar *bin, int precision, int scale)
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{
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  binary2my_decimal(E_DEC_FATAL_ERROR, bin,
                    &decimal_value, precision, scale);
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  decimals= (uint8) decimal_value.frac;
  fixed= 1;
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  max_length= my_decimal_precision_to_length_no_truncation(precision, decimals,
                                                           unsigned_flag);
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}


longlong Item_decimal::val_int()
{
  longlong result;
  my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &result);
  return result;
}

double Item_decimal::val_real()
{
  double result;
  my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &result);
  return result;
}

String *Item_decimal::val_str(String *result)
{
  result->set_charset(&my_charset_bin);
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, result);
  return result;
}

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void Item_decimal::print(String *str, enum_query_type query_type)
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{
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, &str_value);
  str->append(str_value);
}


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bool Item_decimal::eq(const Item *item, bool binary_cmp) const
{
  if (type() == item->type() && item->basic_const_item())
  {
    /*
      We need to cast off const to call val_decimal(). This should
      be OK for a basic constant. Additionally, we can pass 0 as
      a true decimal constant will return its internal decimal
      storage and ignore the argument.
    */
    Item *arg= (Item*) item;
    my_decimal *value= arg->val_decimal(0);
    return !my_decimal_cmp(&decimal_value, value);
  }
  return 0;
}


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void Item_decimal::set_decimal_value(my_decimal *value_par)
{
  my_decimal2decimal(value_par, &decimal_value);
  decimals= (uint8) decimal_value.frac;
  unsigned_flag= !decimal_value.sign();
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  max_length= my_decimal_precision_to_length_no_truncation(decimal_value.intg +
                                                           decimals,
                                                           decimals,
                                                           unsigned_flag);
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}


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String *Item_float::val_str(String *str)
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
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  DBUG_ASSERT(fixed == 1);
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  str->set_real(value,decimals,&my_charset_bin);
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  return str;
}

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my_decimal *Item_float::val_decimal(my_decimal *decimal_value)
{
  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
  double2my_decimal(E_DEC_FATAL_ERROR, value, decimal_value);
  return (decimal_value);
}


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void Item_string::print(String *str, enum_query_type query_type)
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{
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  if (query_type == QT_ORDINARY && is_cs_specified())
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  {
    str->append('_');
    str->append(collation.collation->csname);
  }

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  str->append('\'');
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  if (query_type == QT_ORDINARY ||
      my_charset_same(str_value.charset(), system_charset_info))
  {
    str_value.print(str);
  }
  else
  {
    THD *thd= current_thd;
    LEX_STRING utf8_lex_str;

    thd->convert_string(&utf8_lex_str,
                        system_charset_info,
                        str_value.c_ptr_safe(),
                        str_value.length(),
                        str_value.charset());

    String utf8_str(utf8_lex_str.str,
                    utf8_lex_str.length,
                    system_charset_info);

    utf8_str.print(str);
  }

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  str->append('\'');
}

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double 
double_from_string_with_check (CHARSET_INFO *cs, const char *cptr, char *end)
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{
  int error;
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  char *org_end;
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  double tmp;

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  org_end= end;
  tmp= my_strntod(cs, (char*) cptr, end - cptr, &end, &error);
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  if (error || (end != org_end && !check_if_only_end_space(cs, end, org_end)))
  {
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    char buff[80];
    strmake(buff, cptr, min(sizeof(buff)-1, (size_t) (org_end-cptr)));
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    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "DOUBLE",
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                        buff);
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  }
  return tmp;
}


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double Item_string::val_real()
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{
  DBUG_ASSERT(fixed == 1);
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  return double_from_string_with_check(str_value.charset(),
                                       str_value.ptr(), 
                                       (char *) str_value.ptr() +
                                       str_value.length());
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}


longlong 
longlong_from_string_with_check (CHARSET_INFO *cs, const char *cptr, char *end)
{
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  int err;
  longlong tmp;
  char *org_end= end;

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  tmp= (*(cs->cset->strtoll10))(cs, cptr, &end, &err);
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  /*
    TODO: Give error if we wanted a signed integer and we got an unsigned
    one
  */
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  if (!current_thd->no_errors &&
      (err > 0 ||
       (end != org_end && !check_if_only_end_space(cs, end, org_end))))
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  {
    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                        ER_TRUNCATED_WRONG_VALUE,
                        ER(ER_TRUNCATED_WRONG_VALUE), "INTEGER",
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                        cptr);
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  }
  return tmp;
}


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/**
  @todo
  Give error if we wanted a signed integer and we got an unsigned one
*/
longlong Item_string::val_int()
{
  DBUG_ASSERT(fixed == 1);
  return longlong_from_string_with_check(str_value.charset(), str_value.ptr(),
                             (char *) str_value.ptr()+ str_value.length());
}


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my_decimal *Item_string::val_decimal(my_decimal *decimal_value)
{
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  return val_decimal_from_string(decimal_value);
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}


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bool Item_null::eq(const Item *item, bool binary_cmp) const
{ return item->type() == type(); }
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double Item_null::val_real()
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0.0;
}
longlong Item_null::val_int()
{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0;
}
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/* ARGSUSED */
String *Item_null::val_str(String *str)
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{
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  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
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  null_value=1;
  return 0;
}
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my_decimal *Item_null::val_decimal(my_decimal *decimal_value)
{
  return 0;
}

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Item *Item_null::safe_charset_converter(CHARSET_INFO *tocs)
{
  collation.set(tocs);
  return this;
}

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/*********************** Item_param related ******************************/

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/** 
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  Default function of Item_param::set_param_func, so in case
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  of malformed packet the server won't SIGSEGV.
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*/

static void
default_set_param_func(Item_param *param,
                       uchar **pos __attribute__((unused)),
                       ulong len __attribute__((unused)))
{
  param->set_null();
}

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Item_param::Item_param(uint pos_in_query_arg) :
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  state(NO_VALUE),
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  item_result_type(STRING_RESULT),
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  /* Don't pretend to be a literal unless value for this item is set. */
  item_type(PARAM_ITEM),
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  param_type(MYSQL_TYPE_VARCHAR),
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  pos_in_query(pos_in_query_arg),
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  set_param_func(default_set_param_func),
  limit_clause_param(FALSE)
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{
  name= (char*) "?";
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  /* 
    Since we can't say whenever this item can be NULL or cannot be NULL
    before mysql_stmt_execute(), so we assuming that it can be NULL until
    value is set.
  */
  maybe_null= 1;
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  cnvitem= new Item_string("", 0, &my_charset_bin, DERIVATION_COERCIBLE);
  cnvstr.set(cnvbuf, sizeof(cnvbuf), &my_charset_bin);
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}
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void Item_param::set_null()
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{
  DBUG_ENTER("Item_param::set_null");
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  /* These are cleared after each execution by reset() method */
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  null_value= 1;
  /* 
    Because of NULL and string values we need to set max_length for each new
    placeholder value: user can submit NULL for any placeholder type, and 
    string length can be different in each execution.
  */
  max_length= 0;
  decimals= 0;
  state= NULL_VALUE;
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  item_type= Item::NULL_ITEM;
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  DBUG_VOID_RETURN;
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}

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void Item_param::set_int(longlong i, uint32 max_length_arg)
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{
  DBUG_ENTER("Item_param::set_int");
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  value.integer= (longlong) i;
  state= INT_VALUE;
  max_length= max_length_arg;
  decimals= 0;
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  maybe_null= 0;
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  DBUG_VOID_RETURN;
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}

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void Item_param::set_double(double d)
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{
  DBUG_ENTER("Item_param::set_double");
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  value.real= d;
  state= REAL_VALUE;
  max_length= DBL_DIG + 8;
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  decimals= NOT_FIXED_DEC;
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  maybe_null= 0;
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  DBUG_VOID_RETURN;
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}


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/**
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  Set decimal parameter value from string.

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  @param str      character string
  @param length   string length
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  @note
    As we use character strings to send decimal values in
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    binary protocol, we use str2my_decimal to convert it to
    internal decimal value.
*/
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void Item_param::set_decimal(const char *str, ulong length)
{
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  char *end;
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  DBUG_ENTER("Item_param::set_decimal");

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  end= (char*) str+length;
  str2my_decimal(E_DEC_FATAL_ERROR, str, &decimal_value, &end);
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  state= DECIMAL_VALUE;
  decimals= decimal_value.frac;
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  max_length=
    my_decimal_precision_to_length_no_truncation(decimal_value.precision(),
                                                 decimals, unsigned_flag);
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  maybe_null= 0;
  DBUG_VOID_RETURN;
}


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/**
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  Set parameter value from MYSQL_TIME value.
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  @param tm              datetime value to set (time_type is ignored)
  @param type            type of datetime value
  @param max_length_arg  max length of datetime value as string
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  @note
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    If we value to be stored is not normalized, zero value will be stored
    instead and proper warning will be produced. This function relies on
    the fact that even wrong value sent over binary protocol fits into
    MAX_DATE_STRING_REP_LENGTH buffer.
*/
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void Item_param::set_time(MYSQL_TIME *tm, timestamp_type time_type,
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                          uint32 max_length_arg)
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{ 
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  DBUG_ENTER("Item_param::set_time");
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  value.time= *tm;
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  value.time.time_type= time_type;
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  if (value.time.year > 9999 || value.time.month > 12 ||
      value.time.day > 31 ||
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      (time_type != MYSQL_TIMESTAMP_TIME && value.time.hour > 23) ||
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      value.time.minute > 59 || value.time.second > 59)
  {
    char buff[MAX_DATE_STRING_REP_LENGTH];
    uint length= my_TIME_to_str(&value.time, buff);
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    make_truncated_value_warning(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
                                 buff, length, time_type, 0);
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    set_zero_time(&value.time, MYSQL_TIMESTAMP_ERROR);
  }

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  state= TIME_VALUE;
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  maybe_null= 0;
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  max_length= max_length_arg;
  decimals= 0;
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  DBUG_VOID_RETURN;
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}

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bool Item_param::set_str(const char *str, ulong length)
{
  DBUG_ENTER("Item_param::set_str");
  /*
    Assign string with no conversion: data is converted only after it's
    been written to the binary log.
  */
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  uint dummy_errors;
  if (str_value.copy(str, length, &my_charset_bin, &my_charset_bin,
                     &dummy_errors))
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    DBUG_RETURN(TRUE);
  state= STRING_VALUE;
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  max_length= length;
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  maybe_null= 0;
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  /* max_length and decimals are set after charset conversion */
  /* sic: str may be not null-terminated, don't add DBUG_PRINT here */
  DBUG_RETURN(FALSE);
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}


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bool Item_param::set_longdata(const char *str, ulong length)
{
  DBUG_ENTER("Item_param::set_longdata");

  /*
    If client character set is multibyte, end of long data packet
    may hit at the middle of a multibyte character.  Additionally,
    if binary log is open we must write long data value to the
    binary log in character set of client. This is why we can't
    convert long data to connection character set as it comes
    (here), and first have to concatenate all pieces together,
    write query to the binary log and only then perform conversion.
  */
  if (str_value.append(str, length, &my_charset_bin))
    DBUG_RETURN(TRUE);
  state= LONG_DATA_VALUE;
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  maybe_null= 0;
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  DBUG_RETURN(FALSE);
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}


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/**
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  Set parameter value from user variable value.

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  @param thd   Current thread
  @param entry User variable structure (NULL means use NULL value)
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  @retval
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    0 OK
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  @retval
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    1 Out of memory
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*/

bool Item_param::set_from_user_var(THD *thd, const user_var_entry *entry)
{
  DBUG_ENTER("Item_param::set_from_user_var");
  if (entry && entry->value)
  {
    item_result_type= entry->type;
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    unsigned_flag= entry->unsigned_flag;
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    if (limit_clause_param)
    {
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      bool unused;
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      set_int(entry->val_int(&unused), MY_INT64_NUM_DECIMAL_DIGITS);
      item_type= Item::INT_ITEM;
      DBUG_RETURN(!unsigned_flag && value.integer < 0 ? 1 : 0);
    }
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    switch (item_result_type) {
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    case REAL_RESULT:
      set_double(*(double*)entry->value);
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      item_type= Item::REAL_ITEM;
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      break;
    case INT_RESULT:
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      set_int(*(longlong*)entry->value, MY_INT64_NUM_DECIMAL_DIGITS);
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      item_type= Item::INT_ITEM;
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      break;
    case STRING_RESULT:
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    {
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      CHARSET_INFO *fromcs= entry->collation.collation;
      CHARSET_INFO *tocs= thd->variables.collation_connection;
      uint32 dummy_offset;

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      value.cs_info.character_set_of_placeholder= fromcs;
      value.cs_info.character_set_client= thd->variables.character_set_client;
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      /*
        Setup source and destination character sets so that they
        are different only if conversion is necessary: this will
        make later checks easier.
      */
      value.cs_info.final_character_set_of_str_value=
        String::needs_conversion(0, fromcs, tocs, &dummy_offset) ?
        tocs : fromcs;
      /*
        Exact value of max_length is not known unless data is converted to
        charset of connection, so we have to set it later.
      */
      item_type= Item::STRING_ITEM;

      if (set_str((const char *)entry->value, entry->length))
        DBUG_RETURN(1);
      break;
    }
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    case DECIMAL_RESULT:
    {
      const my_decimal *ent_value= (const my_decimal *)entry->value;
      my_decimal2decimal(ent_value, &decimal_value);
      state= DECIMAL_VALUE;
      decimals= ent_value->frac;
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      max_length=
        my_decimal_precision_to_length_no_truncation(ent_value->precision(),
                                                     decimals, unsigned_flag);
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      item_type= Item::DECIMAL_ITEM;
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      break;
    }
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    default:
      DBUG_ASSERT(0);
      set_null();
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    }
  }
  else
    set_null();

  DBUG_RETURN(0);
}

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/**
  Resets parameter after execution.

  @note
    We clear null_value here instead of setting it in set_* methods,
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    because we want more easily handle case for long data.
*/

void Item_param::reset()
2965
{
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  DBUG_ENTER("Item_param::reset");
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  /* Shrink string buffer if it's bigger than max possible CHAR column */
  if (str_value.alloced_length() > MAX_CHAR_WIDTH)
    str_value.free();
  else
    str_value.length(0);
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  str_value_ptr.length(0);
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  /*
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    We must prevent all charset conversions until data has been written
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    to the binary log.
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  */
  str_value.set_charset(&my_charset_bin);
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  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
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  state= NO_VALUE;
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  maybe_null= 1;
  null_value= 0;
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  /*
    Don't reset item_type to PARAM_ITEM: it's only needed to guard
    us from item optimizations at prepare stage, when item doesn't yet
    contain a literal of some kind.
    In all other cases when this object is accessed its value is
    set (this assumption is guarded by 'state' and
    DBUG_ASSERTS(state != NO_VALUE) in all Item_param::get_*
    methods).
  */
2991
  DBUG_VOID_RETURN;
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}


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int Item_param::save_in_field(Field *field, bool no_conversions)
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{
  field->set_notnull();
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  switch (state) {
  case INT_VALUE:
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    return field->store(value.integer, unsigned_flag);
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  case REAL_VALUE:
    return field->store(value.real);
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  case DECIMAL_VALUE:
    return field->store_decimal(&decimal_value);
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  case TIME_VALUE:
    field->store_time(&value.time, value.time.time_type);
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    return 0;
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    return field->store(str_value.ptr(), str_value.length(),
                        str_value.charset());
  case NULL_VALUE:
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    return set_field_to_null_with_conversions(field, no_conversions);
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  case NO_VALUE:
  default:
    DBUG_ASSERT(0);
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  }
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  return 1;
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}

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bool Item_param::get_time(MYSQL_TIME *res)
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{
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  if (state == TIME_VALUE)
  {
    *res= value.time;
    return 0;
  }
  /*
    If parameter value isn't supplied assertion will fire in val_str()
    which is called from Item::get_time().
  */
  return Item::get_time(res);
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}
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bool Item_param::get_date(MYSQL_TIME *res, uint fuzzydate)
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{
  if (state == TIME_VALUE)
  {
    *res= value.time;
    return 0;
  }
  return Item::get_date(res, fuzzydate);
}


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double Item_param::val_real()
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{
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  switch (state) {
  case REAL_VALUE:
    return value.real;
  case INT_VALUE:
    return (double) value.integer;
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  case DECIMAL_VALUE:
  {
    double result;
    my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &result);
    return result;
  }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
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  {
    int dummy_err;
    char *end_not_used;
    return my_strntod(str_value.charset(), (char*) str_value.ptr(),
                      str_value.length(), &end_not_used, &dummy_err);
  }
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  case TIME_VALUE:
    /*
      This works for example when user says SELECT ?+0.0 and supplies
      time value for the placeholder.
    */
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    return ulonglong2double(TIME_to_ulonglong(&value.time));
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  case NULL_VALUE:
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    return 0.0;
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  default:
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    DBUG_ASSERT(0);
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  }
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  return 0.0;
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} 

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longlong Item_param::val_int() 
{ 
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  switch (state) {
  case REAL_VALUE:
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    return (longlong) rint(value.real);
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  case INT_VALUE:
    return value.integer;
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  case DECIMAL_VALUE:
  {
    longlong i;
    my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &i);
    return i;
  }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    {
      int dummy_err;
      return my_strntoll(str_value.charset(), str_value.ptr(),
                         str_value.length(), 10, (char**) 0, &dummy_err);
    }
  case TIME_VALUE:
    return (longlong) TIME_to_ulonglong(&value.time);
  case NULL_VALUE:
    return 0; 
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  default:
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    DBUG_ASSERT(0);
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  }
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  return 0;
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}

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my_decimal *Item_param::val_decimal(my_decimal *dec)
{
  switch (state) {
  case DECIMAL_VALUE:
    return &decimal_value;
  case REAL_VALUE:
    double2my_decimal(E_DEC_FATAL_ERROR, value.real, dec);
    return dec;
  case INT_VALUE:
    int2my_decimal(E_DEC_FATAL_ERROR, value.integer, unsigned_flag, dec);
    return dec;
  case STRING_VALUE:
  case LONG_DATA_VALUE:
    string2my_decimal(E_DEC_FATAL_ERROR, &str_value, dec);
    return dec;
  case TIME_VALUE:
  {
    longlong i= (longlong) TIME_to_ulonglong(&value.time);
    int2my_decimal(E_DEC_FATAL_ERROR, i, 0, dec);
    return dec;
  }
  case NULL_VALUE:
    return 0; 
  default:
    DBUG_ASSERT(0);
  }
  return 0;
}


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String *Item_param::val_str(String* str) 
{ 
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  switch (state) {
  case STRING_VALUE:
  case LONG_DATA_VALUE:
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    return &str_value_ptr;
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  case REAL_VALUE:
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    str->set_real(value.real, NOT_FIXED_DEC, &my_charset_bin);
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    return str;
  case INT_VALUE:
    str->set(value.integer, &my_charset_bin);
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    return str;
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  case DECIMAL_VALUE:
    if (my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value,
                          0, 0, 0, str) <= 1)
      return str;
    return NULL;
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  case TIME_VALUE:
  {
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    if (str->reserve(MAX_DATE_STRING_REP_LENGTH))
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      break;
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    str->length((uint) my_TIME_to_str(&value.time, (char*) str->ptr()));
    str->set_charset(&my_charset_bin);
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    return str;
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  }
  case NULL_VALUE:
    return NULL; 
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  default:
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    DBUG_ASSERT(0);
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  }
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  return str;
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}
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/**
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  Return Param item values in string format, for generating the dynamic 
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  query used in update/binary logs.

  @todo
    - Change interface and implementation to fill log data in place
    and avoid one more memcpy/alloc between str and log string.
    - In case of error we need to notify replication
    that binary log contains wrong statement 
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*/

3190
const String *Item_param::query_val_str(String* str) const
3191
{
3192 3193
  switch (state) {
  case INT_VALUE:
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    str->set_int(value.integer, unsigned_flag, &my_charset_bin);
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    break;
  case REAL_VALUE:
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    str->set_real(value.real, NOT_FIXED_DEC, &my_charset_bin);
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    break;
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  case DECIMAL_VALUE:
    if (my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value,
                          0, 0, 0, str) > 1)
      return &my_null_string;
    break;
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  case TIME_VALUE:
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    {
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      char *buf, *ptr;
      str->length(0);
      /*
        TODO: in case of error we need to notify replication
        that binary log contains wrong statement 
      */
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      if (str->reserve(MAX_DATE_STRING_REP_LENGTH+3))
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        break; 

      /* Create date string inplace */
      buf= str->c_ptr_quick();
      ptr= buf;
      *ptr++= '\'';
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      ptr+= (uint) my_TIME_to_str(&value.time, ptr);
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      *ptr++= '\'';
      str->length((uint32) (ptr - buf));
      break;
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    }
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
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    {
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      str->length(0);
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      append_query_string(value.cs_info.character_set_client, &str_value, str);
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      break;
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    }
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  case NULL_VALUE:
    return &my_null_string;
  default:
    DBUG_ASSERT(0);
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  }
  return str;
}
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/**
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  Convert string from client character set to the character set of
  connection.
*/

bool Item_param::convert_str_value(THD *thd)
{
  bool rc= FALSE;
  if (state == STRING_VALUE || state == LONG_DATA_VALUE)
  {
    /*
      Check is so simple because all charsets were set up properly
      in setup_one_conversion_function, where typecode of
      placeholder was also taken into account: the variables are different
      here only if conversion is really necessary.
    */
    if (value.cs_info.final_character_set_of_str_value !=
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        value.cs_info.character_set_of_placeholder)
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    {
      rc= thd->convert_string(&str_value,
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                              value.cs_info.character_set_of_placeholder,
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                              value.cs_info.final_character_set_of_str_value);
    }
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    else
      str_value.set_charset(value.cs_info.final_character_set_of_str_value);
    /* Here str_value is guaranteed to be in final_character_set_of_str_value */

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    max_length= str_value.numchars() * str_value.charset()->mbmaxlen;
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    decimals= 0;
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    /*
      str_value_ptr is returned from val_str(). It must be not alloced
      to prevent it's modification by val_str() invoker.
    */
    str_value_ptr.set(str_value.ptr(), str_value.length(),
                      str_value.charset());
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    /* Synchronize item charset with value charset */
    collation.set(str_value.charset(), DERIVATION_COERCIBLE);
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  }
  return rc;
}

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bool Item_param::basic_const_item() const
{
  if (state == NO_VALUE || state == TIME_VALUE)
    return FALSE;
  return TRUE;
}

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Item *
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Item_param::clone_item()
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{
  /* see comments in the header file */
  switch (state) {
  case NULL_VALUE:
    return new Item_null(name);
  case INT_VALUE:
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    return (unsigned_flag ?
            new Item_uint(name, value.integer, max_length) :
            new Item_int(name, value.integer, max_length));
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  case REAL_VALUE:
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    return new Item_float(name, value.real, decimals, max_length);
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    return new Item_string(name, str_value.c_ptr_quick(), str_value.length(),
                           str_value.charset());
  case TIME_VALUE:
    break;
  case NO_VALUE:
  default:
    DBUG_ASSERT(0);
  };
  return 0;
}


bool
Item_param::eq(const Item *arg, bool binary_cmp) const
{
  Item *item;
  if (!basic_const_item() || !arg->basic_const_item() || arg->type() != type())
    return FALSE;
  /*
    We need to cast off const to call val_int(). This should be OK for
    a basic constant.
  */
  item= (Item*) arg;

  switch (state) {
  case NULL_VALUE:
    return TRUE;
  case INT_VALUE:
    return value.integer == item->val_int() &&
           unsigned_flag == item->unsigned_flag;
  case REAL_VALUE:
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    return value.real == item->val_real();
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  case STRING_VALUE:
  case LONG_DATA_VALUE:
    if (binary_cmp)
      return !stringcmp(&str_value, &item->str_value);
    return !sortcmp(&str_value, &item->str_value, collation.collation);
  default:
    break;
  }
  return FALSE;
}

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/* End of Item_param related */

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void Item_param::print(String *str, enum_query_type query_type)
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{
  if (state == NO_VALUE)
  {
    str->append('?');
  }
  else
  {
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    char buffer[STRING_BUFFER_USUAL_SIZE];
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    String tmp(buffer, sizeof(buffer), &my_charset_bin);
    const String *res;
    res= query_val_str(&tmp);
    str->append(*res);
  }
}


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/**
  Preserve the original parameter types and values
  when re-preparing a prepared statement.

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  @details Copy parameter type information and conversion
  function pointers from a parameter of the old statement
  to the corresponding parameter of the new one.
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  Move parameter values from the old parameters to the new
  one. We simply "exchange" the values, which allows
  to save on allocation and character set conversion in
  case a parameter is a string or a blob/clob.

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  The old parameter gets the value of this one, which
  ensures that all memory of this parameter is freed
  correctly.

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  @param[in]  src   parameter item of the original
                    prepared statement
*/

void
Item_param::set_param_type_and_swap_value(Item_param *src)
{
  unsigned_flag= src->unsigned_flag;
  param_type= src->param_type;
  set_param_func= src->set_param_func;
  item_type= src->item_type;
  item_result_type= src->item_result_type;

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  collation.set(src->collation);
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  maybe_null= src->maybe_null;
  null_value= src->null_value;
  max_length= src->max_length;
  decimals= src->decimals;
  state= src->state;
  value= src->value;

  decimal_value.swap(src->decimal_value);
  str_value.swap(src->str_value);
  str_value_ptr.swap(src->str_value_ptr);
}

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/****************************************************************************
  Item_copy
****************************************************************************/
Item_copy *Item_copy::create (Item *item)
{
  switch (item->result_type())
  {
    case STRING_RESULT:
      return new Item_copy_string (item);
    case REAL_RESULT: 
      return new Item_copy_float (item);
    case INT_RESULT:
      return item->unsigned_flag ? 
        new Item_copy_uint (item) : new Item_copy_int (item);
    case DECIMAL_RESULT:
      return new Item_copy_decimal (item);
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    default:
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      DBUG_ASSERT (0);
  }
  /* should not happen */
  return NULL;
}

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/****************************************************************************
  Item_copy_string
****************************************************************************/
3436

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double Item_copy_string::val_real()
{
  int err_not_used;
  char *end_not_used;
  return (null_value ? 0.0 :
          my_strntod(str_value.charset(), (char*) str_value.ptr(),
                     str_value.length(), &end_not_used, &err_not_used));
}

longlong Item_copy_string::val_int()
{
  int err;
  return null_value ? LL(0) : my_strntoll(str_value.charset(),str_value.ptr(),
                                          str_value.length(),10, (char**) 0,
                                          &err); 
}


int Item_copy_string::save_in_field(Field *field, bool no_conversions)
{
  return save_str_value_in_field(field, &str_value);
}


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void Item_copy_string::copy()
{
  String *res=item->val_str(&str_value);
  if (res && res != &str_value)
    str_value.copy(*res);
  null_value=item->null_value;
}

/* ARGSUSED */
String *Item_copy_string::val_str(String *str)
{
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  // Item_copy_string is used without fix_fields call
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  if (null_value)
    return (String*) 0;
  return &str_value;
}

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my_decimal *Item_copy_string::val_decimal(my_decimal *decimal_value)
{
  // Item_copy_string is used without fix_fields call
  if (null_value)
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    return (my_decimal *) 0;
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  string2my_decimal(E_DEC_FATAL_ERROR, &str_value, decimal_value);
  return (decimal_value);
}


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/****************************************************************************
  Item_copy_int
****************************************************************************/

void Item_copy_int::copy()
{
  cached_value= item->val_int();
  null_value=item->null_value;
}

static int save_int_value_in_field (Field *field, longlong nr, 
                                    bool null_value, bool unsigned_flag);

int Item_copy_int::save_in_field(Field *field, bool no_conversions)
{
  return save_int_value_in_field(field, cached_value, 
                                 null_value, unsigned_flag);
}


String *Item_copy_int::val_str(String *str)
{
  if (null_value)
    return (String *) 0;

  str->set(cached_value, &my_charset_bin);
  return str;
}


my_decimal *Item_copy_int::val_decimal(my_decimal *decimal_value)
{
  if (null_value)
    return (my_decimal *) 0;

  int2my_decimal(E_DEC_FATAL_ERROR, cached_value, unsigned_flag, decimal_value);
  return decimal_value;
}


/****************************************************************************
  Item_copy_uint
****************************************************************************/

String *Item_copy_uint::val_str(String *str)
{
  if (null_value)
    return (String *) 0;

  str->set((ulonglong) cached_value, &my_charset_bin);
  return str;
}


/****************************************************************************
  Item_copy_float
****************************************************************************/

String *Item_copy_float::val_str(String *str)
{
  if (null_value)
    return (String *) 0;
  else
  {
    double nr= val_real();
    str->set_real(nr,decimals, &my_charset_bin);
    return str;
  }
}


my_decimal *Item_copy_float::val_decimal(my_decimal *decimal_value)
{
  if (null_value)
    return (my_decimal *) 0;
  else
  {
    double nr= val_real();
    double2my_decimal(E_DEC_FATAL_ERROR, nr, decimal_value);
    return decimal_value;
  }
}


int Item_copy_float::save_in_field(Field *field, bool no_conversions)
{
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
  return field->store(cached_value);
}


/****************************************************************************
  Item_copy_decimal
****************************************************************************/

int Item_copy_decimal::save_in_field(Field *field, bool no_conversions)
{
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
  return field->store_decimal(&cached_value);
}


String *Item_copy_decimal::val_str(String *result)
{
  if (null_value)
    return (String *) 0;
  result->set_charset(&my_charset_bin);
  my_decimal2string(E_DEC_FATAL_ERROR, &cached_value, 0, 0, 0, result);
  return result;
}


double Item_copy_decimal::val_real()
{
  if (null_value)
    return 0.0;
  else
  {
    double result;
    my_decimal2double(E_DEC_FATAL_ERROR, &cached_value, &result);
    return result;
  }
}


longlong Item_copy_decimal::val_int()
{
  if (null_value)
    return LL(0);
  else
  {
    longlong result;
    my_decimal2int(E_DEC_FATAL_ERROR, &cached_value, unsigned_flag, &result);
    return result;
  }
}


void Item_copy_decimal::copy()
{
  my_decimal *nr= item->val_decimal(&cached_value);
  if (nr && nr != &cached_value)
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    my_decimal2decimal (nr, &cached_value);
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  null_value= item->null_value;
}


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/*
3641
  Functions to convert item to field (for send_fields)
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*/

/* ARGSUSED */
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bool Item::fix_fields(THD *thd, Item **ref)
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{
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  // We do not check fields which are fixed during construction
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  DBUG_ASSERT(fixed == 0 || basic_const_item());
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  fixed= 1;
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  return FALSE;
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}

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void Item_ref_null_helper::save_val(Field *to)
{
  DBUG_ASSERT(fixed == 1);
  (*ref)->save_val(to);
  owner->was_null|= null_value= (*ref)->null_value;
}


3663
double Item_ref_null_helper::val_real()
3664
{
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  DBUG_ASSERT(fixed == 1);
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  double tmp= (*ref)->val_result();
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  owner->was_null|= null_value= (*ref)->null_value;
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  return tmp;
}
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longlong Item_ref_null_helper::val_int()
{
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  DBUG_ASSERT(fixed == 1);
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  longlong tmp= (*ref)->val_int_result();
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  owner->was_null|= null_value= (*ref)->null_value;
3677 3678
  return tmp;
}
3679 3680


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my_decimal *Item_ref_null_helper::val_decimal(my_decimal *decimal_value)
{
  DBUG_ASSERT(fixed == 1);
  my_decimal *val= (*ref)->val_decimal_result(decimal_value);
  owner->was_null|= null_value= (*ref)->null_value;
  return val;
}


bool Item_ref_null_helper::val_bool()
{
  DBUG_ASSERT(fixed == 1);
  bool val= (*ref)->val_bool_result();
  owner->was_null|= null_value= (*ref)->null_value;
  return val;
}


3699 3700
String* Item_ref_null_helper::val_str(String* s)
{
3701
  DBUG_ASSERT(fixed == 1);
3702
  String* tmp= (*ref)->str_result(s);
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  owner->was_null|= null_value= (*ref)->null_value;
3704 3705
  return tmp;
}
3706 3707


3708
bool Item_ref_null_helper::get_date(MYSQL_TIME *ltime, uint fuzzydate)
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{  
  return (owner->was_null|= null_value= (*ref)->get_date(ltime, fuzzydate));
}
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/**
  Mark item and SELECT_LEXs as dependent if item was resolved in
  outer SELECT.
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  @param thd             thread handler
  @param last            select from which current item depend
  @param current         current select
  @param resolved_item   item which was resolved in outer SELECT(for warning)
  @param mark_item       item which should be marked (can be differ in case of
                         substitution)
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*/

3726
static bool mark_as_dependent(THD *thd, SELECT_LEX *last, SELECT_LEX *current,
3727
                              Item_ident *resolved_item,
3728
                              Item_ident *mark_item)
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{
3730 3731 3732 3733
  const char *db_name= (resolved_item->db_name ?
                        resolved_item->db_name : "");
  const char *table_name= (resolved_item->table_name ?
                           resolved_item->table_name : "");
3734
  /* store pointer on SELECT_LEX from which item is dependent */
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  if (mark_item && mark_item->can_be_depended)
3736
    mark_item->depended_from= last;
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  if (current->mark_as_dependent(thd, last, /** resolved_item psergey-thu
    **/mark_item))
    return TRUE;
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  if (thd->lex->describe & DESCRIBE_EXTENDED)
3741
  {
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    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
		 ER_WARN_FIELD_RESOLVED, ER(ER_WARN_FIELD_RESOLVED),
                 db_name, (db_name[0] ? "." : ""),
                 table_name, (table_name [0] ? "." : ""),
                 resolved_item->field_name,
                 current->select_number, last->select_number);
3748
  }
3749
  return FALSE;
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}


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/**
  Mark range of selects and resolved identifier (field/reference)
  item as dependent.
3756

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  @param thd             thread handler
  @param last_select     select where resolved_item was resolved
  @param current_sel     current select (select where resolved_item was placed)
  @param found_field     field which was found during resolving
  @param found_item      Item which was found during resolving (if resolved
                         identifier belongs to VIEW)
  @param resolved_item   Identifier which was resolved

  @note
3766 3767 3768 3769 3770 3771 3772 3773 3774
    We have to mark all items between current_sel (including) and
    last_select (excluding) as dependend (select before last_select should
    be marked with actual table mask used by resolved item, all other with
    OUTER_REF_TABLE_BIT) and also write dependence information to Item of
    resolved identifier.
*/

void mark_select_range_as_dependent(THD *thd,
                                    SELECT_LEX *last_select,
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                                    SELECT_LEX *current_sel,
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                                    Field *found_field, Item *found_item,
                                    Item_ident *resolved_item)
{
  /*
    Go from current SELECT to SELECT where field was resolved (it
    have to be reachable from current SELECT, because it was already
    done once when we resolved this field and cached result of
    resolving)
  */
  SELECT_LEX *previous_select= current_sel;
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  for (; previous_select->outer_select() != last_select;
       previous_select= previous_select->outer_select())
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  {
    Item_subselect *prev_subselect_item=
      previous_select->master_unit()->item;
    prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
    prev_subselect_item->const_item_cache= 0;
  }
  {
    Item_subselect *prev_subselect_item=
      previous_select->master_unit()->item;
    Item_ident *dependent= resolved_item;
    if (found_field == view_ref_found)
    {
      Item::Type type= found_item->type();
      prev_subselect_item->used_tables_cache|=
        found_item->used_tables();
      dependent= ((type == Item::REF_ITEM || type == Item::FIELD_ITEM) ?
                  (Item_ident*) found_item :
                  0);
    }
    else
      prev_subselect_item->used_tables_cache|=
        found_field->table->map;
    prev_subselect_item->const_item_cache= 0;
    mark_as_dependent(thd, last_select, current_sel, resolved_item,
                      dependent);
  }
}
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3817
/**
3818 3819
  Search a GROUP BY clause for a field with a certain name.

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  Search the GROUP BY list for a column named as find_item. When searching
  preference is given to columns that are qualified with the same table (and
  database) name as the one being searched for.
3823

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  @param find_item     the item being searched for
  @param group_list    GROUP BY clause
3826

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  @return
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    - the found item on success
    - NULL if find_item is not in group_list
*/

static Item** find_field_in_group_list(Item *find_item, ORDER *group_list)
{
  const char *db_name;
  const char *table_name;
  const char *field_name;
  ORDER      *found_group= NULL;
  int         found_match_degree= 0;
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  Item_ident *cur_field;
3840
  int         cur_match_degree= 0;
3841
  char        name_buff[SAFE_NAME_LEN+1];
3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852

  if (find_item->type() == Item::FIELD_ITEM ||
      find_item->type() == Item::REF_ITEM)
  {
    db_name=    ((Item_ident*) find_item)->db_name;
    table_name= ((Item_ident*) find_item)->table_name;
    field_name= ((Item_ident*) find_item)->field_name;
  }
  else
    return NULL;

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  if (db_name && lower_case_table_names)
  {
    /* Convert database to lower case for comparison */
    strmake(name_buff, db_name, sizeof(name_buff)-1);
    my_casedn_str(files_charset_info, name_buff);
    db_name= name_buff;
  }

3861
  DBUG_ASSERT(field_name != 0);
3862 3863 3864

  for (ORDER *cur_group= group_list ; cur_group ; cur_group= cur_group->next)
  {
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    if ((*(cur_group->item))->real_item()->type() == Item::FIELD_ITEM)
3866
    {
3867
      cur_field= (Item_ident*) *cur_group->item;
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      cur_match_degree= 0;
      
3870
      DBUG_ASSERT(cur_field->field_name != 0);
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      if (!my_strcasecmp(system_charset_info,
                         cur_field->field_name, field_name))
        ++cur_match_degree;
      else
        continue;

      if (cur_field->table_name && table_name)
      {
        /* If field_name is qualified by a table name. */
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        if (my_strcasecmp(table_alias_charset, cur_field->table_name, table_name))
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          /* Same field names, different tables. */
          return NULL;

        ++cur_match_degree;
        if (cur_field->db_name && db_name)
        {
          /* If field_name is also qualified by a database name. */
          if (strcmp(cur_field->db_name, db_name))
            /* Same field names, different databases. */
            return NULL;
          ++cur_match_degree;
        }
      }

      if (cur_match_degree > found_match_degree)
      {
        found_match_degree= cur_match_degree;
        found_group= cur_group;
      }
      else if (found_group && (cur_match_degree == found_match_degree) &&
               ! (*(found_group->item))->eq(cur_field, 0))
      {
        /*
          If the current resolve candidate matches equally well as the current
          best match, they must reference the same column, otherwise the field
          is ambiguous.
        */
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        my_error(ER_NON_UNIQ_ERROR, MYF(0),
                 find_item->full_name(), current_thd->where);
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        return NULL;
      }
    }
  }

  if (found_group)
    return found_group->item;
  else
    return NULL;
}


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3923
/**
3924 3925
  Resolve a column reference in a sub-select.

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  Resolve a column reference (usually inside a HAVING clause) against the
  SELECT and GROUP BY clauses of the query described by 'select'. The name
  resolution algorithm searches both the SELECT and GROUP BY clauses, and in
  case of a name conflict prefers GROUP BY column names over SELECT names. If
  both clauses contain different fields with the same names, a warning is
  issued that name of 'ref' is ambiguous. We extend ANSI SQL in that when no
  GROUP BY column is found, then a HAVING name is resolved as a possibly
  derived SELECT column. This extension is allowed only if the
  MODE_ONLY_FULL_GROUP_BY sql mode isn't enabled.

  @param thd     current thread
  @param ref     column reference being resolved
3938
  @param select  the select that ref is resolved against
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3939 3940

  @note
3941 3942
    The resolution procedure is:
    - Search for a column or derived column named col_ref_i [in table T_j]
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    in the SELECT clause of Q.
3944
    - Search for a column named col_ref_i [in table T_j]
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    in the GROUP BY clause of Q.
3946
    - If found different columns with the same name in GROUP BY and SELECT
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    - issue a warning and return the GROUP BY column,
    - otherwise
    - if the MODE_ONLY_FULL_GROUP_BY mode is enabled return error
    - else return the found SELECT column.
3951 3952


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  @return
    - NULL - there was an error, and the error was already reported
    - not_found_item - the item was not resolved, no error was reported
    - resolved item - if the item was resolved
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*/

static Item**
resolve_ref_in_select_and_group(THD *thd, Item_ident *ref, SELECT_LEX *select)
{
  Item **group_by_ref= NULL;
  Item **select_ref= NULL;
3964
  ORDER *group_list= select->group_list.first;
3965 3966
  bool ambiguous_fields= FALSE;
  uint counter;
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  enum_resolution_type resolution;
3968 3969 3970 3971 3972

  /*
    Search for a column or derived column named as 'ref' in the SELECT
    clause of the current select.
  */
3973 3974
  if (!(select_ref= find_item_in_list(ref, *(select->get_item_list()),
                                      &counter, REPORT_EXCEPT_NOT_FOUND,
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                                      &resolution)))
3976
    return NULL; /* Some error occurred. */
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  if (resolution == RESOLVED_AGAINST_ALIAS)
    ref->alias_name_used= TRUE;
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  /* If this is a non-aggregated field inside HAVING, search in GROUP BY. */
  if (select->having_fix_field && !ref->with_sum_func && group_list)
  {
    group_by_ref= find_field_in_group_list(ref, group_list);
    
    /* Check if the fields found in SELECT and GROUP BY are the same field. */
    if (group_by_ref && (select_ref != not_found_item) &&
        !((*group_by_ref)->eq(*select_ref, 0)))
    {
      ambiguous_fields= TRUE;
      push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN, ER_NON_UNIQ_ERROR,
                          ER(ER_NON_UNIQ_ERROR), ref->full_name(),
                          current_thd->where);

    }
  }

3997
  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
3998
      select->having_fix_field  &&
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      select_ref != not_found_item && !group_by_ref)
  {
    /*
      Report the error if fields was found only in the SELECT item list and
      the strict mode is enabled.
    */
    my_error(ER_NON_GROUPING_FIELD_USED, MYF(0),
             ref->name, "HAVING");
    return NULL;
  }
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  if (select_ref != not_found_item || group_by_ref)
  {
    if (select_ref != not_found_item && !ambiguous_fields)
    {
4013
      DBUG_ASSERT(*select_ref != 0);
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      if (!select->ref_pointer_array[counter])
4015
      {
4016 4017
        my_error(ER_ILLEGAL_REFERENCE, MYF(0),
                 ref->name, "forward reference in item list");
4018 4019
        return NULL;
      }
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      DBUG_ASSERT((*select_ref)->fixed);
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      return (select->ref_pointer_array + counter);
    }
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    if (group_by_ref)
4024
      return group_by_ref;
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    DBUG_ASSERT(FALSE);
    return NULL; /* So there is no compiler warning. */
4027
  }
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  return (Item**) not_found_item;
4030 4031 4032
}


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4033
/**
4034 4035
  Resolve the name of an outer select column reference.

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4036 4037
  The method resolves the column reference represented by 'this' as a column
  present in outer selects that contain current select.
4038

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4039 4040 4041 4042 4043
  In prepared statements, because of cache, find_field_in_tables()
  can resolve fields even if they don't belong to current context.
  In this case this method only finds appropriate context and marks
  current select as dependent. The found reference of field should be
  provided in 'from_field'.
4044

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  @param[in] thd             current thread
  @param[in,out] from_field  found field reference or (Field*)not_found_field
  @param[in,out] reference   view column if this item was resolved to a
    view column
4049

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4050 4051 4052 4053 4054 4055 4056
  @note
    This is the inner loop of Item_field::fix_fields:
  @code
        for each outer query Q_k beginning from the inner-most one
        {
          search for a column or derived column named col_ref_i
          [in table T_j] in the FROM clause of Q_k;
4057

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          if such a column is not found
            Search for a column or derived column named col_ref_i
            [in table T_j] in the SELECT and GROUP clauses of Q_k.
        }
  @endcode

  @retval
    1   column succefully resolved and fix_fields() should continue.
  @retval
    0   column fully fixed and fix_fields() should return FALSE
  @retval
    -1  error occured
4070
*/
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4071

4072 4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089
int
Item_field::fix_outer_field(THD *thd, Field **from_field, Item **reference)
{
  enum_parsing_place place= NO_MATTER;
  bool field_found= (*from_field != not_found_field);
  bool upward_lookup= FALSE;

  /*
    If there are outer contexts (outer selects, but current select is
    not derived table or view) try to resolve this reference in the
    outer contexts.

    We treat each subselect as a separate namespace, so that different
    subselects may contain columns with the same names. The subselects
    are searched starting from the innermost.
  */
  Name_resolution_context *last_checked_context= context;
  Item **ref= (Item **) not_found_item;
4090 4091
  SELECT_LEX *current_sel= (SELECT_LEX *) thd->lex->current_select;
  Name_resolution_context *outer_context= 0;
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  SELECT_LEX *select= 0;
4093 4094 4095 4096
  /* Currently derived tables cannot be correlated */
  if (current_sel->master_unit()->first_select()->linkage !=
      DERIVED_TABLE_TYPE)
    outer_context= context->outer_context;
4097 4098 4099 4100
  for (;
       outer_context;
       outer_context= outer_context->outer_context)
  {
4101
    select= outer_context->select_lex;
4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131
    Item_subselect *prev_subselect_item=
      last_checked_context->select_lex->master_unit()->item;
    last_checked_context= outer_context;
    upward_lookup= TRUE;

    place= prev_subselect_item->parsing_place;
    /*
      If outer_field is set, field was already found by first call
      to find_field_in_tables(). Only need to find appropriate context.
    */
    if (field_found && outer_context->select_lex !=
        cached_table->select_lex)
      continue;
    /*
      In case of a view, find_field_in_tables() writes the pointer to
      the found view field into '*reference', in other words, it
      substitutes this Item_field with the found expression.
    */
    if (field_found || (*from_field= find_field_in_tables(thd, this,
                                          outer_context->
                                            first_name_resolution_table,
                                          outer_context->
                                            last_name_resolution_table,
                                          reference,
                                          IGNORE_EXCEPT_NON_UNIQUE,
                                          TRUE, TRUE)) !=
        not_found_field)
    {
      if (*from_field)
      {
4132 4133 4134 4135 4136 4137 4138 4139 4140 4141
        if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
            select->cur_pos_in_select_list != UNDEF_POS)
        {
          /*
            As this is an outer field it should be added to the list of
            non aggregated fields of the outer select.
          */
          marker= select->cur_pos_in_select_list;
          select->non_agg_fields.push_back(this);
        }
4142 4143 4144 4145
        if (*from_field != view_ref_found)
        {
          prev_subselect_item->used_tables_cache|= (*from_field)->table->map;
          prev_subselect_item->const_item_cache= 0;
4146
          set_field(*from_field);
4147
          if (!last_checked_context->select_lex->having_fix_field &&
4148 4149
              select->group_list.elements &&
              (place == SELECT_LIST || place == IN_HAVING))
4150 4151 4152
          {
            Item_outer_ref *rf;
            /*
4153 4154 4155 4156 4157 4158 4159
              If an outer field is resolved in a grouping select then it
              is replaced for an Item_outer_ref object. Otherwise an
              Item_field object is used.
              The new Item_outer_ref object is saved in the inner_refs_list of
              the outer select. Here it is only created. It can be fixed only
              after the original field has been fixed and this is done in the
              fix_inner_refs() function.
4160
            */
4161 4162
            ;
            if (!(rf= new Item_outer_ref(context, this)))
4163
              return -1;
4164
            thd->change_item_tree(reference, rf);
4165
            select->inner_refs_list.push_back(rf);
4166
            rf->in_sum_func= thd->lex->in_sum_func;
4167
          }
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          /*
            A reference is resolved to a nest level that's outer or the same as
            the nest level of the enclosing set function : adjust the value of
            max_arg_level for the function if it's needed.
          */
4173
          if (thd->lex->in_sum_func &&
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              thd->lex->in_sum_func->nest_level >= select->nest_level)
4175
          {
4176
            Item::Type ref_type= (*reference)->type();
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            set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                          select->nest_level);
            set_field(*from_field);
            fixed= 1;
            mark_as_dependent(thd, last_checked_context->select_lex,
                              context->select_lex, this,
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                              ((ref_type == REF_ITEM ||
                                ref_type == FIELD_ITEM) ?
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                               (Item_ident*) (*reference) : 0));
            return 0;
          }
        }
        else
        {
4191
          Item::Type ref_type= (*reference)->type();
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          prev_subselect_item->used_tables_cache|=
            (*reference)->used_tables();
          prev_subselect_item->const_item_cache&=
            (*reference)->const_item();
          mark_as_dependent(thd, last_checked_context->select_lex,
                            context->select_lex, this,
4198
                            ((ref_type == REF_ITEM || ref_type == FIELD_ITEM) ?
4199 4200
                             (Item_ident*) (*reference) :
                             0));
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          context->select_lex->
              register_dependency_item(last_checked_context->select_lex,
                                       reference);
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          /*
            A reference to a view field had been found and we
            substituted it instead of this Item (find_field_in_tables
            does it by assigning the new value to *reference), so now
            we can return from this function.
          */
          return 0;
        }
      }
      break;
    }

    /* Search in SELECT and GROUP lists of the outer select. */
4217
    if (place != IN_WHERE && place != IN_ON)
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    {
      if (!(ref= resolve_ref_in_select_and_group(thd, this, select)))
        return -1; /* Some error occurred (e.g. ambiguous names). */
      if (ref != not_found_item)
      {
        DBUG_ASSERT(*ref && (*ref)->fixed);
        prev_subselect_item->used_tables_cache|= (*ref)->used_tables();
        prev_subselect_item->const_item_cache&= (*ref)->const_item();
        break;
      }
    }

    /*
      Reference is not found in this select => this subquery depend on
      outer select (or we just trying to find wrong identifier, in this
      case it does not matter which used tables bits we set)
    */
    prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
    prev_subselect_item->const_item_cache= 0;
  }

  DBUG_ASSERT(ref != 0);
  if (!*from_field)
    return -1;
  if (ref == not_found_item && *from_field == not_found_field)
  {
    if (upward_lookup)
    {
      // We can't say exactly what absent table or field
      my_error(ER_BAD_FIELD_ERROR, MYF(0), full_name(), thd->where);
    }
    else
    {
      /* Call find_field_in_tables only to report the error */
      find_field_in_tables(thd, this,
                           context->first_name_resolution_table,
                           context->last_name_resolution_table,
                           reference, REPORT_ALL_ERRORS,
4256
                           !any_privileges, TRUE);
4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276
    }
    return -1;
  }
  else if (ref != not_found_item)
  {
    Item *save;
    Item_ref *rf;

    /* Should have been checked in resolve_ref_in_select_and_group(). */
    DBUG_ASSERT(*ref && (*ref)->fixed);
    /*
      Here, a subset of actions performed by Item_ref::set_properties
      is not enough. So we pass ptr to NULL into Item_[direct]_ref
      constructor, so no initialization is performed, and call 
      fix_fields() below.
    */
    save= *ref;
    *ref= NULL;                             // Don't call set_properties()
    rf= (place == IN_HAVING ?
         new Item_ref(context, ref, (char*) table_name,
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4277
                      (char*) field_name, alias_name_used) :
4278
         (!select->group_list.elements ?
4279
         new Item_direct_ref(context, ref, (char*) table_name,
4280 4281 4282
                             (char*) field_name, alias_name_used) :
         new Item_outer_ref(context, ref, (char*) table_name,
                            (char*) field_name, alias_name_used)));
4283 4284 4285
    *ref= save;
    if (!rf)
      return -1;
4286 4287 4288 4289 4290 4291

    if (place != IN_HAVING && select->group_list.elements)
    {
      outer_context->select_lex->inner_refs_list.push_back((Item_outer_ref*)rf);
      ((Item_outer_ref*)rf)->in_sum_func= thd->lex->in_sum_func;
    }
4292 4293 4294 4295 4296 4297 4298 4299 4300 4301
    thd->change_item_tree(reference, rf);
    /*
      rf is Item_ref => never substitute other items (in this case)
      during fix_fields() => we can use rf after fix_fields()
    */
    DBUG_ASSERT(!rf->fixed);                // Assured by Item_ref()
    if (rf->fix_fields(thd, reference) || rf->check_cols(1))
      return -1;

    mark_as_dependent(thd, last_checked_context->select_lex,
4302
                      context->select_lex, rf,
4303
                      rf);
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4304 4305 4306 4307
    context->select_lex->
              register_dependency_item(last_checked_context->select_lex,
                                       reference);

4308 4309 4310 4311 4312 4313
    return 0;
  }
  else
  {
    mark_as_dependent(thd, last_checked_context->select_lex,
                      context->select_lex,
4314
                      this, (Item_ident*)*reference);
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4315 4316 4317
    context->select_lex->
              register_dependency_item(last_checked_context->select_lex,
                                       reference);
4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340
    if (last_checked_context->select_lex->having_fix_field)
    {
      Item_ref *rf;
      rf= new Item_ref(context,
                       (cached_table->db[0] ? cached_table->db : 0),
                       (char*) cached_table->alias, (char*) field_name);
      if (!rf)
        return -1;
      thd->change_item_tree(reference, rf);
      /*
        rf is Item_ref => never substitute other items (in this case)
        during fix_fields() => we can use rf after fix_fields()
      */
      DBUG_ASSERT(!rf->fixed);                // Assured by Item_ref()
      if (rf->fix_fields(thd, reference) || rf->check_cols(1))
        return -1;
      return 0;
    }
  }
  return 1;
}


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4341
/**
4342 4343
  Resolve the name of a column reference.

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4344 4345 4346
  The method resolves the column reference represented by 'this' as a column
  present in one of: FROM clause, SELECT clause, GROUP BY clause of a query
  Q, or in outer queries that contain Q.
4347

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4348 4349
  The name resolution algorithm used is (where [T_j] is an optional table
  name that qualifies the column name):
4350

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4351 4352 4353 4354 4355
  @code
    resolve_column_reference([T_j].col_ref_i)
    {
      search for a column or derived column named col_ref_i
      [in table T_j] in the FROM clause of Q;
4356

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4357 4358
      if such a column is NOT found AND    // Lookup in outer queries.
         there are outer queries
4359
      {
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4360
        for each outer query Q_k beginning from the inner-most one
4361
        {
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4362 4363
          search for a column or derived column named col_ref_i
          [in table T_j] in the FROM clause of Q_k;
4364

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4365 4366 4367
          if such a column is not found
            Search for a column or derived column named col_ref_i
            [in table T_j] in the SELECT and GROUP clauses of Q_k.
4368 4369
        }
      }
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4370 4371
    }
  @endcode
4372 4373 4374 4375

    Notice that compared to Item_ref::fix_fields, here we first search the FROM
    clause, and then we search the SELECT and GROUP BY clauses.

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4376 4377 4378 4379 4380
  @param[in]     thd        current thread
  @param[in,out] reference  view column if this item was resolved to a
    view column

  @retval
4381
    TRUE  if error
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4382
  @retval
4383 4384 4385
    FALSE on success
*/

4386
bool Item_field::fix_fields(THD *thd, Item **reference)
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4387
{
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4388
  DBUG_ASSERT(fixed == 0);
4389 4390 4391
  Field *from_field= (Field *)not_found_field;
  bool outer_fixed= false;

4392
  if (!field)					// If field is not checked
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4393
  {
4394 4395 4396 4397 4398
    /*
      In case of view, find_field_in_tables() write pointer to view field
      expression to 'reference', i.e. it substitute that expression instead
      of this Item_field
    */
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4399 4400 4401
    if ((from_field= find_field_in_tables(thd, this,
                                          context->first_name_resolution_table,
                                          context->last_name_resolution_table,
4402
                                          reference,
4403 4404 4405
                                          thd->lex->use_only_table_context ?
                                            REPORT_ALL_ERRORS : 
                                            IGNORE_EXCEPT_NON_UNIQUE,
4406
                                          !any_privileges,
4407
                                          TRUE)) ==
4408
	not_found_field)
4409
    {
4410
      int ret;
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4411 4412 4413 4414
      /* Look up in current select's item_list to find aliased fields */
      if (thd->lex->current_select->is_item_list_lookup)
      {
        uint counter;
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4415
        enum_resolution_type resolution;
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4416 4417
        Item** res= find_item_in_list(this, thd->lex->current_select->item_list,
                                      &counter, REPORT_EXCEPT_NOT_FOUND,
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4418
                                      &resolution);
4419 4420
        if (!res)
          return 1;
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4421 4422
        if (resolution == RESOLVED_AGAINST_ALIAS)
          alias_name_used= TRUE;
4423
        if (res != (Item **)not_found_item)
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4424
        {
4425 4426 4427
          if ((*res)->type() == Item::FIELD_ITEM)
          {
            /*
4428 4429 4430 4431
              It's an Item_field referencing another Item_field in the select
              list.
              Use the field from the Item_field in the select list and leave
              the Item_field instance in place.
4432
            */
4433

4434
            Field *new_field= (*((Item_field**)res))->field;
4435

4436
            if (new_field == NULL)
4437 4438 4439 4440 4441 4442 4443
            {
              /* The column to which we link isn't valid. */
              my_error(ER_BAD_FIELD_ERROR, MYF(0), (*res)->name, 
                       current_thd->where);
              return(1);
            }

4444
            set_field(new_field);
4445 4446 4447 4448 4449 4450 4451 4452 4453
            return 0;
          }
          else
          {
            /*
              It's not an Item_field in the select list so we must make a new
              Item_ref to point to the Item in the select list and replace the
              Item_field created by the parser with the new Item_ref.
            */
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4454
            Item_ref *rf= new Item_ref(context, db_name,table_name,field_name);
4455 4456
            if (!rf)
              return 1;
4457 4458 4459
            bool ret= rf->fix_fields(thd, (Item **) &rf) || rf->check_cols(1);
            if (ret)
              return TRUE;
4460 4461 4462 4463 4464
           
            SELECT_LEX *select= thd->lex->current_select;
            thd->change_item_tree(reference,
                                  select->parsing_place == IN_GROUP_BY && 
				  alias_name_used  ?  *rf->ref : rf);
4465 4466

            return FALSE;
4467
          }
4468 4469
        }
      }
4470 4471 4472
      if ((ret= fix_outer_field(thd, &from_field, reference)) < 0)
        goto error;
      outer_fixed= TRUE;
4473 4474
      if (!ret)
        goto mark_non_agg_field;
4475
    }
4476
    else if (!from_field)
4477
      goto error;
4478

4479
    if (!outer_fixed && cached_table && cached_table->select_lex &&
4480 4481
        context->select_lex &&
        cached_table->select_lex != context->select_lex)
4482 4483 4484 4485 4486
    {
      int ret;
      if ((ret= fix_outer_field(thd, &from_field, reference)) < 0)
        goto error;
      outer_fixed= 1;
4487 4488
      if (!ret)
        goto mark_non_agg_field;
4489 4490
    }

unknown's avatar
VIEW  
unknown committed
4491 4492 4493 4494
    /*
      if it is not expression from merged VIEW we will set this field.

      We can leave expression substituted from view for next PS/SP rexecution
4495
      (i.e. do not register this substitution for reverting on cleanup()
unknown's avatar
VIEW  
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4496
      (register_item_tree_changing())), because this subtree will be
4497
      fix_field'ed during setup_tables()->setup_underlying() (i.e. before
unknown's avatar
VIEW  
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4498 4499 4500 4501 4502
      all other expressions of query, and references on tables which do
      not present in query will not make problems.

      Also we suppose that view can't be changed during PS/SP life.
    */
4503 4504 4505 4506
    if (from_field == view_ref_found)
      return FALSE;

    set_field(from_field);
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4507 4508 4509 4510 4511
    if (thd->lex->in_sum_func &&
        thd->lex->in_sum_func->nest_level == 
        thd->lex->current_select->nest_level)
      set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                    thd->lex->current_select->nest_level);
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4512
  }
4513
  else if (thd->mark_used_columns != MARK_COLUMNS_NONE)
4514
  {
4515
    TABLE *table= field->table;
4516 4517
    MY_BITMAP *current_bitmap, *other_bitmap;
    if (thd->mark_used_columns == MARK_COLUMNS_READ)
4518
    {
4519 4520 4521 4522 4523 4524 4525 4526 4527 4528 4529 4530 4531 4532
      current_bitmap= table->read_set;
      other_bitmap=   table->write_set;
    }
    else
    {
      current_bitmap= table->write_set;
      other_bitmap=   table->read_set;
    }
    if (!bitmap_fast_test_and_set(current_bitmap, field->field_index))
    {
      if (!bitmap_is_set(other_bitmap, field->field_index))
      {
        /* First usage of column */
        table->used_fields++;                     // Used to optimize loops
4533
        /* purecov: begin inspected */
4534
        table->covering_keys.intersect(field->part_of_key);
4535
        /* purecov: end */
4536
      }
4537
    }
4538
  }
unknown's avatar
VIEW  
unknown committed
4539 4540 4541 4542
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  if (any_privileges)
  {
    char *db, *tab;
4543 4544
    db= cached_table->get_db_name();
    tab= cached_table->get_table_name();
unknown's avatar
VIEW  
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4545 4546 4547 4548
    if (!(have_privileges= (get_column_grant(thd, &field->table->grant,
                                             db, tab, field_name) &
                            VIEW_ANY_ACL)))
    {
4549
      my_error(ER_COLUMNACCESS_DENIED_ERROR, MYF(0),
4550 4551
               "ANY", thd->security_ctx->priv_user,
               thd->security_ctx->host_or_ip, field_name, tab);
4552
      goto error;
unknown's avatar
VIEW  
unknown committed
4553 4554 4555
    }
  }
#endif
4556
  fixed= 1;
4557 4558 4559 4560 4561 4562 4563
  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
      !outer_fixed && !thd->lex->in_sum_func &&
      thd->lex->current_select->cur_pos_in_select_list != UNDEF_POS)
  {
    thd->lex->current_select->non_agg_fields.push_back(this);
    marker= thd->lex->current_select->cur_pos_in_select_list;
  }
4564 4565 4566 4567 4568 4569 4570 4571
mark_non_agg_field:
  if (fixed && thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
  {
    /*
      Mark selects according to presence of non aggregated fields.
      Fields from outer selects added to the aggregate function
      outer_fields list as its unknown at the moment whether it's
      aggregated or not.
4572 4573 4574 4575
      We're using either the select lex of the cached table (if present)
      or the field's resolution context. context->select_lex is 
      safe for use because it's either the SELECT we want to use 
      (the current level) or a stub added by non-SELECT queries.
4576
    */
4577 4578
    SELECT_LEX *select_lex= cached_table ? 
      cached_table->select_lex : context->select_lex;
4579
    if (!thd->lex->in_sum_func)
4580
      select_lex->full_group_by_flag|= NON_AGG_FIELD_USED;
4581 4582 4583 4584 4585 4586
    else
    {
      if (outer_fixed)
        thd->lex->in_sum_func->outer_fields.push_back(this);
      else if (thd->lex->in_sum_func->nest_level !=
          thd->lex->current_select->nest_level)
4587
        select_lex->full_group_by_flag|= NON_AGG_FIELD_USED;
4588 4589
    }
  }
4590
  return FALSE;
4591 4592 4593 4594

error:
  context->process_error(thd);
  return TRUE;
unknown's avatar
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4595 4596
}

4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611
/*
  @brief
  Mark virtual columns as used in a partitioning expression 
*/

bool Item_field::vcol_in_partition_func_processor(uchar *int_arg)
{
  DBUG_ASSERT(fixed);
  if (field->vcol_info)
  {
    field->vcol_info->mark_as_in_partitioning_expr();
  }
  return FALSE;
}

4612 4613 4614 4615 4616 4617 4618 4619

Item *Item_field::safe_charset_converter(CHARSET_INFO *tocs)
{
  no_const_subst= 1;
  return Item::safe_charset_converter(tocs);
}


unknown's avatar
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4620 4621
void Item_field::cleanup()
{
unknown's avatar
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4622
  DBUG_ENTER("Item_field::cleanup");
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4623
  Item_ident::cleanup();
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4624
  depended_from= NULL;
4625 4626
  /*
    Even if this object was created by direct link to field in setup_wild()
unknown's avatar
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4627
    it will be linked correctly next time by name of field and table alias.
4628 4629
    I.e. we can drop 'field'.
   */
4630
  field= result_field= 0;
4631
  item_equal= NULL;
4632
  null_value= FALSE;
4633
  DBUG_VOID_RETURN;
4634
}
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4635

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4636 4637
/**
  Find a field among specified multiple equalities.
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4638

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4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651
  The function first searches the field among multiple equalities
  of the current level (in the cond_equal->current_level list).
  If it fails, it continues searching in upper levels accessed
  through a pointer cond_equal->upper_levels.
  The search terminates as soon as a multiple equality containing 
  the field is found. 

  @param cond_equal   reference to list of multiple equalities where
                      the field (this object) is to be looked for

  @return
    - First Item_equal containing the field, if success
    - 0, otherwise
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4652
*/
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4653

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4654 4655 4656 4657 4658 4659 4660 4661 4662 4663 4664 4665 4666 4667 4668 4669 4670 4671 4672 4673 4674
Item_equal *Item_field::find_item_equal(COND_EQUAL *cond_equal)
{
  Item_equal *item= 0;
  while (cond_equal)
  {
    List_iterator_fast<Item_equal> li(cond_equal->current_level);
    while ((item= li++))
    {
      if (item->contains(field))
        return item;
    }
    /* 
      The field is not found in any of the multiple equalities
      of the current level. Look for it in upper levels
    */
    cond_equal= cond_equal->upper_levels;
  }
  return 0;
}


unknown's avatar
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4675
/**
4676
  Check whether a field item can be substituted for an equal item
4677

4678 4679 4680
  @details
  The function checks whether a substitution of a field item for
  an equal item is valid.
4681

4682 4683
  @param arg   *arg != NULL && **arg <-> the field is in the context
               where substitution for an equal item is valid
unknown's avatar
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4684 4685

  @note
4686
    The following statement is not always true:
unknown's avatar
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4687
  @n
4688
    x=y => F(x)=F(x/y).
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4689
  @n
4690
    This means substitution of an item for an equal item not always
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4691 4692 4693 4694 4695
    yields an equavalent condition. Here's an example:
    @code
    'a'='a '
    (LENGTH('a')=1) != (LENGTH('a ')=2)
  @endcode
4696 4697
    Such a substitution is surely valid if either the substituted
    field is not of a STRING type or if it is an argument of
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4698
    a comparison predicate.
4699

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4700
  @retval
4701
    TRUE   substitution is valid
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4702
  @retval
4703 4704 4705
    FALSE  otherwise
*/

4706
bool Item_field::subst_argument_checker(uchar **arg)
4707
{
4708 4709
  return (!(*arg) && (result_type() != STRING_RESULT)) ||
          ((*arg) && (**arg));
4710 4711 4712
}


4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724 4725 4726 4727 4728 4729 4730
/**
  Convert a numeric value to a zero-filled string

  @param[in,out]  item   the item to operate on
  @param          field  The field that this value is equated to

  This function converts a numeric value to a string. In this conversion
  the zero-fill flag of the field is taken into account.
  This is required so the resulting string value can be used instead of
  the field reference when propagating equalities.
*/

static void convert_zerofill_number_to_string(Item **item, Field_num *field)
{
  char buff[MAX_FIELD_WIDTH],*pos;
  String tmp(buff,sizeof(buff), field->charset()), *res;

  res= (*item)->val_str(&tmp);
4731 4732 4733 4734 4735 4736 4737 4738
  if ((*item)->is_null())
    *item= new Item_null();
  else
  {
    field->prepend_zeros(res);
    pos= (char *) sql_strmake (res->ptr(), res->length());
    *item= new Item_string(pos, res->length(), field->charset());
  }
4739 4740 4741
}


unknown's avatar
unknown committed
4742
/**
4743
  Set a pointer to the multiple equality the field reference belongs to
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4744
  (if any).
unknown's avatar
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4745

4746
  @details
unknown's avatar
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4747 4748 4749 4750 4751 4752 4753 4754 4755 4756 4757 4758
  The function looks for a multiple equality containing the field item
  among those referenced by arg.
  In the case such equality exists the function does the following.
  If the found multiple equality contains a constant, then the field
  reference is substituted for this constant, otherwise it sets a pointer
  to the multiple equality in the field item.


  @param arg    reference to list of multiple equalities where
                the field (this object) is to be looked for

  @note
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4759
    This function is supposed to be called as a callback parameter in calls
unknown's avatar
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4760
    of the compile method.
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4761

unknown's avatar
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4762 4763 4764
  @return
    - pointer to the replacing constant item, if the field item was substituted
    - pointer to the field item, otherwise.
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4765
*/
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4766

4767
Item *Item_field::equal_fields_propagator(uchar *arg)
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4768 4769 4770 4771 4772 4773 4774
{
  if (no_const_subst)
    return this;
  item_equal= find_item_equal((COND_EQUAL *) arg);
  Item *item= 0;
  if (item_equal)
    item= item_equal->get_const();
4775 4776 4777 4778 4779 4780 4781 4782 4783 4784 4785
  /*
    Disable const propagation for items used in different comparison contexts.
    This must be done because, for example, Item_hex_string->val_int() is not
    the same as (Item_hex_string->val_str() in BINARY column)->val_int().
    We cannot simply disable the replacement in a particular context (
    e.g. <bin_col> = <int_col> AND <bin_col> = <hex_string>) since
    Items don't know the context they are in and there are functions like 
    IF (<hex_string>, 'yes', 'no').
    The same problem occurs when comparing a DATE/TIME field with a
    DATE/TIME represented as an int and as a string.
  */
unknown's avatar
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4786
  if (!item ||
4787
      (cmp_context != IMPOSSIBLE_RESULT && item->cmp_context != cmp_context))
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4788
    item= this;
4789 4790
  else if (field && (field->flags & ZEROFILL_FLAG) && IS_NUM(field->type()))
  {
4791 4792 4793 4794 4795 4796
    /*
      We don't need to zero-fill timestamp columns here because they will be 
      first converted to a string (in date/time format) and compared as such if
      compared with another string.
    */
    if (item && field->type() != FIELD_TYPE_TIMESTAMP && cmp_context != INT_RESULT)
4797 4798 4799 4800
      convert_zerofill_number_to_string(&item, (Field_num *)field);
    else
      item= this;
  }
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4801 4802 4803 4804
  return item;
}


unknown's avatar
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4805 4806 4807 4808
/**
  Mark the item to not be part of substitution if it's not a binary item.

  See comments in Arg_comparator::set_compare_func() for details.
4809 4810
*/

4811
bool Item_field::set_no_const_sub(uchar *arg)
4812 4813 4814
{
  if (field->charset() != &my_charset_bin)
    no_const_subst=1;
4815
  return FALSE;
4816 4817 4818
}


unknown's avatar
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4819
/**
unknown's avatar
unknown committed
4820
  Replace an Item_field for an equal Item_field that evaluated earlier
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4821
  (if any).
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4822

4823
  @details
Igor Babaev's avatar
Igor Babaev committed
4824 4825
  If this->item_equal points to some item and coincides with arg then
  the function returns a pointer to an item that is taken from
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unknown committed
4826 4827 4828 4829 4830 4831 4832
  the very beginning of the item_equal list which the Item_field
  object refers to (belongs to) unless item_equal contains  a constant
  item. In this case the function returns this constant item, 
  (if the substitution does not require conversion).   
  If the Item_field object does not refer any Item_equal object
  'this' is returned .

Igor Babaev's avatar
Igor Babaev committed
4833
  @param arg   NULL or points to so some item of the Item_equal type  
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4834 4835 4836


  @note
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4837
    This function is supposed to be called as a callback parameter in calls
4838
    of the transformer method.
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4839

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4840 4841 4842 4843
  @return
    - pointer to a replacement Item_field if there is a better equal item or
      a pointer to a constant equal item;
    - this - otherwise.
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4844 4845
*/

4846
Item *Item_field::replace_equal_field(uchar *arg)
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4847
{
Igor Babaev's avatar
Igor Babaev committed
4848
  if (item_equal && item_equal == (Item_equal *) arg)
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4849
  {
4850 4851 4852
    Item *const_item= item_equal->get_const();
    if (const_item)
    {
4853
      if (cmp_context != IMPOSSIBLE_RESULT &&
4854 4855 4856 4857
          const_item->cmp_context != cmp_context)
        return this;
      return const_item;
    }
4858 4859 4860
    Item_field *subst= (Item_field *)(item_equal->get_first(this));
    if (subst)
      subst= (Item_field *) (subst->real_item());
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Igor Babaev committed
4861
    if (subst && !field->eq(subst->field))
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4862
      return subst;
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4863
  }
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4864
  return this;
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}
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4866

4867

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4868
void Item::init_make_field(Send_field *tmp_field,
4869
			   enum enum_field_types field_type_arg)
4870
{
4871
  char *empty_name= (char*) "";
4872
  tmp_field->db_name=		empty_name;
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  tmp_field->org_table_name=	empty_name;
  tmp_field->org_col_name=	empty_name;
  tmp_field->table_name=	empty_name;
  tmp_field->col_name=		name;
4877
  tmp_field->charsetnr=         collation.collation->number;
4878 4879 4880
  tmp_field->flags=             (maybe_null ? 0 : NOT_NULL_FLAG) | 
                                (my_binary_compare(collation.collation) ?
                                 BINARY_FLAG : 0);
4881
  tmp_field->type=              field_type_arg;
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  tmp_field->length=max_length;
  tmp_field->decimals=decimals;
4884 4885
  if (unsigned_flag)
    tmp_field->flags |= UNSIGNED_FLAG;
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}

4888
void Item::make_field(Send_field *tmp_field)
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4889
{
4890
  init_make_field(tmp_field, field_type());
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}


4894
enum_field_types Item::string_field_type() const
4895
{
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4896
  enum_field_types f_type= MYSQL_TYPE_VAR_STRING;
4897
  if (max_length >= 16777216)
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    f_type= MYSQL_TYPE_LONG_BLOB;
4899
  else if (max_length >= 65536)
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4900
    f_type= MYSQL_TYPE_MEDIUM_BLOB;
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4901
  return f_type;
4902 4903 4904 4905 4906 4907
}


void Item_empty_string::make_field(Send_field *tmp_field)
{
  init_make_field(tmp_field, string_field_type());
4908 4909
}

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4910

4911
enum_field_types Item::field_type() const
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4912
{
4913
  switch (result_type()) {
4914
  case STRING_RESULT:  return string_field_type();
4915 4916 4917
  case INT_RESULT:     return MYSQL_TYPE_LONGLONG;
  case DECIMAL_RESULT: return MYSQL_TYPE_NEWDECIMAL;
  case REAL_RESULT:    return MYSQL_TYPE_DOUBLE;
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4918 4919 4920
  case ROW_RESULT:
  default:
    DBUG_ASSERT(0);
4921 4922
    return MYSQL_TYPE_VARCHAR;
  }
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4923 4924
}

4925

4926 4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937 4938 4939 4940
bool Item::is_datetime()
{
  switch (field_type())
  {
    case MYSQL_TYPE_DATE:
    case MYSQL_TYPE_DATETIME:
    case MYSQL_TYPE_TIMESTAMP:
      return TRUE;
    default:
      break;
  }
  return FALSE;
}


4941
String *Item::check_well_formed_result(String *str, bool send_error)
4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952 4953 4954 4955 4956
{
  /* Check whether we got a well-formed string */
  CHARSET_INFO *cs= str->charset();
  int well_formed_error;
  uint wlen= cs->cset->well_formed_len(cs,
                                       str->ptr(), str->ptr() + str->length(),
                                       str->length(), &well_formed_error);
  if (wlen < str->length())
  {
    THD *thd= current_thd;
    char hexbuf[7];
    enum MYSQL_ERROR::enum_warning_level level;
    uint diff= str->length() - wlen;
    set_if_smaller(diff, 3);
    octet2hex(hexbuf, str->ptr() + wlen, diff);
4957 4958 4959 4960 4961 4962 4963 4964
    if (send_error)
    {
      my_error(ER_INVALID_CHARACTER_STRING, MYF(0),
               cs->csname,  hexbuf);
      return 0;
    }
    if ((thd->variables.sql_mode &
         (MODE_STRICT_TRANS_TABLES | MODE_STRICT_ALL_TABLES)))
4965 4966 4967 4968 4969 4970 4971 4972 4973 4974 4975 4976 4977 4978 4979 4980
    {
      level= MYSQL_ERROR::WARN_LEVEL_ERROR;
      null_value= 1;
      str= 0;
    }
    else
    {
      level= MYSQL_ERROR::WARN_LEVEL_WARN;
      str->length(wlen);
    }
    push_warning_printf(thd, level, ER_INVALID_CHARACTER_STRING,
                        ER(ER_INVALID_CHARACTER_STRING), cs->csname, hexbuf);
  }
  return str;
}

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unknown committed
4981 4982 4983 4984 4985 4986 4987 4988 4989 4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000 5001 5002 5003 5004 5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 5023
/*
  Compare two items using a given collation
  
  SYNOPSIS
    eq_by_collation()
    item               item to compare with
    binary_cmp         TRUE <-> compare as binaries
    cs                 collation to use when comparing strings

  DESCRIPTION
    This method works exactly as Item::eq if the collation cs coincides with
    the collation of the compared objects. Otherwise, first the collations that
    differ from cs are replaced for cs and then the items are compared by
    Item::eq. After the comparison the original collations of items are
    restored.

  RETURN
    1    compared items has been detected as equal   
    0    otherwise
*/

bool Item::eq_by_collation(Item *item, bool binary_cmp, CHARSET_INFO *cs)
{
  CHARSET_INFO *save_cs= 0;
  CHARSET_INFO *save_item_cs= 0;
  if (collation.collation != cs)
  {
    save_cs= collation.collation;
    collation.collation= cs;
  }
  if (item->collation.collation != cs)
  {
    save_item_cs= item->collation.collation;
    item->collation.collation= cs;
  }
  bool res= eq(item, binary_cmp);
  if (save_cs)
    collation.collation= save_cs;
  if (save_item_cs)
    item->collation.collation= save_item_cs;
  return res;
}  

5024

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5025 5026
/**
  Create a field to hold a string value from an item.
5027

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5028 5029 5030
  If max_length > CONVERT_IF_BIGGER_TO_BLOB create a blob @n
  If max_length > 0 create a varchar @n
  If max_length == 0 create a CHAR(0) 
5031

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5032
  @param table		Table for which the field is created
5033 5034 5035 5036
*/

Field *Item::make_string_field(TABLE *table)
{
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5037
  Field *field;
5038 5039
  DBUG_ASSERT(collation.collation);
  if (max_length/collation.collation->mbmaxlen > CONVERT_IF_BIGGER_TO_BLOB)
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5040
    field= new Field_blob(max_length, maybe_null, name,
5041
                          collation.collation);
5042
  /* Item_type_holder holds the exact type, do not change it */
5043
  else if (max_length > 0 &&
5044
      (type() != Item::TYPE_HOLDER || field_type() != MYSQL_TYPE_STRING))
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5045
    field= new Field_varstring(max_length, maybe_null, name, table->s,
5046
                               collation.collation);
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5047 5048 5049 5050 5051 5052
  else
    field= new Field_string(max_length, maybe_null, name,
                            collation.collation);
  if (field)
    field->init(table);
  return field;
5053 5054 5055
}


unknown's avatar
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5056 5057
/**
  Create a field based on field_type of argument.
5058 5059

  For now, this is only used to create a field for
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5060
  IFNULL(x,something) and time functions
5061

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5062 5063 5064 5065
  @retval
    NULL  error
  @retval
    \#    Created field
5066 5067
*/

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5068
Field *Item::tmp_table_field_from_field_type(TABLE *table, bool fixed_length)
5069
{
5070 5071 5072 5073
  /*
    The field functions defines a field to be not null if null_ptr is not 0
  */
  uchar *null_ptr= maybe_null ? (uchar*) "" : 0;
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5074
  Field *field;
5075 5076

  switch (field_type()) {
5077
  case MYSQL_TYPE_DECIMAL:
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5078
  case MYSQL_TYPE_NEWDECIMAL:
5079
    field= Field_new_decimal::create_from_item(this);
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5080
    break;
5081
  case MYSQL_TYPE_TINY:
5082
    field= new Field_tiny((uchar*) 0, max_length, null_ptr, 0, Field::NONE,
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5083 5084
			  name, 0, unsigned_flag);
    break;
5085
  case MYSQL_TYPE_SHORT:
5086
    field= new Field_short((uchar*) 0, max_length, null_ptr, 0, Field::NONE,
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5087 5088
			   name, 0, unsigned_flag);
    break;
5089
  case MYSQL_TYPE_LONG:
5090
    field= new Field_long((uchar*) 0, max_length, null_ptr, 0, Field::NONE,
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5091 5092
			  name, 0, unsigned_flag);
    break;
5093 5094
#ifdef HAVE_LONG_LONG
  case MYSQL_TYPE_LONGLONG:
5095
    field= new Field_longlong((uchar*) 0, max_length, null_ptr, 0, Field::NONE,
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5096 5097
			      name, 0, unsigned_flag);
    break;
5098
#endif
5099
  case MYSQL_TYPE_FLOAT:
5100
    field= new Field_float((uchar*) 0, max_length, null_ptr, 0, Field::NONE,
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5101 5102
			   name, decimals, 0, unsigned_flag);
    break;
5103
  case MYSQL_TYPE_DOUBLE:
5104
    field= new Field_double((uchar*) 0, max_length, null_ptr, 0, Field::NONE,
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5105 5106
			    name, decimals, 0, unsigned_flag);
    break;
5107
  case MYSQL_TYPE_NULL:
5108
    field= new Field_null((uchar*) 0, max_length, Field::NONE,
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5109 5110
			  name, &my_charset_bin);
    break;
5111
  case MYSQL_TYPE_INT24:
5112
    field= new Field_medium((uchar*) 0, max_length, null_ptr, 0, Field::NONE,
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unknown committed
5113 5114
			    name, 0, unsigned_flag);
    break;
5115
  case MYSQL_TYPE_NEWDATE:
5116
  case MYSQL_TYPE_DATE:
5117
    field= new Field_newdate(maybe_null, name, &my_charset_bin);
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5118
    break;
5119
  case MYSQL_TYPE_TIME:
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5120 5121
    field= new Field_time(maybe_null, name, &my_charset_bin);
    break;
5122
  case MYSQL_TYPE_TIMESTAMP:
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5123 5124
    field= new Field_timestamp(maybe_null, name, &my_charset_bin);
    break;
5125
  case MYSQL_TYPE_DATETIME:
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5126 5127
    field= new Field_datetime(maybe_null, name, &my_charset_bin);
    break;
5128
  case MYSQL_TYPE_YEAR:
5129
    field= new Field_year((uchar*) 0, max_length, null_ptr, 0, Field::NONE,
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5130 5131
			  name);
    break;
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5132
  case MYSQL_TYPE_BIT:
5133
    field= new Field_bit_as_char(NULL, max_length, null_ptr, 0,
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5134 5135
                                 Field::NONE, name);
    break;
5136
  default:
5137
    /* This case should never be chosen */
5138 5139
    DBUG_ASSERT(0);
    /* If something goes awfully wrong, it's better to get a string than die */
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5140 5141 5142 5143 5144 5145 5146 5147
  case MYSQL_TYPE_STRING:
    if (fixed_length && max_length < CONVERT_IF_BIGGER_TO_BLOB)
    {
      field= new Field_string(max_length, maybe_null, name,
                              collation.collation);
      break;
    }
    /* Fall through to make_string_field() */
5148 5149
  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
5150
  case MYSQL_TYPE_VAR_STRING:
5151
  case MYSQL_TYPE_VARCHAR:
5152
    return make_string_field(table);
5153 5154 5155 5156
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
5157
    if (this->type() == Item::TYPE_HOLDER)
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5158 5159
      field= new Field_blob(max_length, maybe_null, name, collation.collation,
                            1);
5160
    else
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5161
      field= new Field_blob(max_length, maybe_null, name, collation.collation);
5162
    break;					// Blob handled outside of case
5163
#ifdef HAVE_SPATIAL
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5164
  case MYSQL_TYPE_GEOMETRY:
5165 5166
    field= new Field_geom(max_length, maybe_null,
                          name, table->s, get_geometry_type());
5167
#endif /* HAVE_SPATIAL */
5168
  }
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  if (field)
    field->init(table);
  return field;
5172 5173
}

5174

5175 5176
/* ARGSUSED */
void Item_field::make_field(Send_field *tmp_field)
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5177
{
5178
  field->make_field(tmp_field);
5179
  DBUG_ASSERT(tmp_field->table_name != 0);
5180 5181
  if (name)
    tmp_field->col_name=name;			// Use user supplied name
5182 5183 5184 5185
  if (table_name)
    tmp_field->table_name= table_name;
  if (db_name)
    tmp_field->db_name= db_name;
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5186 5187
}

5188

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5189
/**
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5190
  Save a field value in another field
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5191

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5192 5193 5194 5195
  @param from             Field to take the value from
  @param [out] null_value Pointer to the null_value flag to set
  @param to               Field to save the value in
  @param no_conversions   How to deal with NULL value
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5196

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5197 5198 5199 5200 5201 5202 5203 5204 5205 5206 5207 5208 5209 5210 5211
  @details
  The function takes the value of the field 'from' and, if this value
  is not null, it saves in the field 'to' setting off the flag referenced
  by 'null_value'. Otherwise this flag is set on and field 'to' is
  also set to null possibly with conversion.

  @note
  This function is used by the functions Item_field::save_in_field,
  Item_field::save_org_in_field and Item_ref::save_in_field

  @retval FALSE OK
  @retval TRUE  Error

*/

Sergey Petrunya's avatar
Sergey Petrunya committed
5212
static int save_field_in_field(Field *from, bool *null_value,
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5213
                               Field *to, bool no_conversions)
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5214
{
5215
  int res;
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5216 5217
  DBUG_ENTER("save_field_in_field");
  if (from->is_null())
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5218
  {
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5219 5220
    (*null_value)= 1;
    DBUG_RETURN(set_field_to_null_with_conversions(to, no_conversions));
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5221
  }
5222 5223 5224 5225 5226
  to->set_notnull();

  /*
    If we're setting the same field as the one we're reading from there's 
    nothing to do. This can happen in 'SET x = x' type of scenarios.
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5227 5228
  */
  if (to == from)
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5229
  {
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5230 5231
    (*null_value)= 0;
    DBUG_RETURN(0);
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5232
  }
5233

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  res= field_conv(to, from);
  (*null_value)= 0;
  DBUG_RETURN(res);
}


/**
  Set a field's value from a item.
*/

void Item_field::save_org_in_field(Field *to)
{
  save_field_in_field(field, &null_value, to, TRUE);
}


int Item_field::save_in_field(Field *to, bool no_conversions)
{
  return save_field_in_field(result_field, &null_value, to, no_conversions);
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5253 5254
}

5255

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5256 5257
/**
  Store null in field.
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5258

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5259 5260
  This is used on INSERT.
  Allow NULL to be inserted in timestamp and auto_increment values.
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5261

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5262
  @param field		Field where we want to store NULL
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5263

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5264 5265 5266 5267 5268
  @retval
    0   ok
  @retval
    1   Field doesn't support NULL values and can't handle 'field = NULL'
*/
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5269

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5270
int Item_null::save_in_field(Field *field, bool no_conversions)
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5271
{
5272
  return set_field_to_null_with_conversions(field, no_conversions);
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5273 5274 5275
}


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5276 5277
/**
  Store null in field.
5278

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5279
  @param field		Field where we want to store NULL
5280

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5281
  @retval
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5282
    0	 OK
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5283
  @retval
5284
    1	 Field doesn't support NULL values
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5285
*/
5286

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5287
int Item_null::save_safe_in_field(Field *field)
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5288 5289 5290 5291 5292
{
  return set_field_to_null(field);
}


5293 5294 5295
/*
  This implementation can lose str_value content, so if the
  Item uses str_value to store something, it should
5296 5297 5298 5299
  reimplement it's ::save_in_field() as Item_string, for example, does.

  Note: all Item_XXX::val_str(str) methods must NOT rely on the fact that
  str != str_value. For example, see fix for bug #44743.
5300 5301
*/

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5302
int Item::save_in_field(Field *field, bool no_conversions)
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5303
{
5304
  int error;
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5305
  if (result_type() == STRING_RESULT ||
5306 5307
      (result_type() == REAL_RESULT &&
       field->result_type() == STRING_RESULT))
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5308 5309
  {
    String *result;
5310
    CHARSET_INFO *cs= collation.collation;
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5311
    char buff[MAX_FIELD_WIDTH];		// Alloc buffer for small columns
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    str_value.set_quick(buff, sizeof(buff), cs);
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5313 5314
    result=val_str(&str_value);
    if (null_value)
5315
    {
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5316
      str_value.set_quick(0, 0, cs);
5317
      return set_field_to_null_with_conversions(field, no_conversions);
5318
    }
5319 5320 5321

    /* NOTE: If null_value == FALSE, "result" must be not NULL.  */

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5322
    field->set_notnull();
5323
    error=field->store(result->ptr(),result->length(),cs);
5324
    str_value.set_quick(0, 0, cs);
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5325 5326 5327
  }
  else if (result_type() == REAL_RESULT)
  {
5328
    double nr= val_real();
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5329 5330 5331
    if (null_value)
      return set_field_to_null(field);
    field->set_notnull();
5332
    error=field->store(nr);
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5333
  }
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  else if (result_type() == DECIMAL_RESULT)
  {
    my_decimal decimal_value;
    my_decimal *value= val_decimal(&decimal_value);
    if (null_value)
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5339
      return set_field_to_null_with_conversions(field, no_conversions);
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5340 5341 5342
    field->set_notnull();
    error=field->store_decimal(value);
  }
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5343 5344 5345 5346
  else
  {
    longlong nr=val_int();
    if (null_value)
5347
      return set_field_to_null_with_conversions(field, no_conversions);
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5348
    field->set_notnull();
5349
    error=field->store(nr, unsigned_flag);
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5350
  }
5351
  return error ? error : (field->table->in_use->is_error() ? 1 : 0);
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}

5354

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5355
int Item_string::save_in_field(Field *field, bool no_conversions)
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{
  String *result;
  result=val_str(&str_value);
5359
  return save_str_value_in_field(field, result);
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}

5362

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5363
int Item_uint::save_in_field(Field *field, bool no_conversions)
5364
{
5365
  /* Item_int::save_in_field handles both signed and unsigned. */
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5366
  return Item_int::save_in_field(field, no_conversions);
5367 5368
}

5369 5370
static int save_int_value_in_field (Field *field, longlong nr, 
                                    bool null_value, bool unsigned_flag)
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{
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
5375
  return field->store(nr, unsigned_flag);
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}

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5379 5380 5381 5382 5383 5384
int Item_int::save_in_field(Field *field, bool no_conversions)
{
  return save_int_value_in_field (field, val_int(), null_value, unsigned_flag);
}


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int Item_decimal::save_in_field(Field *field, bool no_conversions)
{
  field->set_notnull();
  return field->store_decimal(&decimal_value);
}


5392 5393 5394 5395 5396 5397 5398 5399 5400 5401 5402 5403 5404 5405 5406 5407
bool Item_int::eq(const Item *arg, bool binary_cmp) const
{
  /* No need to check for null value as basic constant can't be NULL */
  if (arg->basic_const_item() && arg->type() == type())
  {
    /*
      We need to cast off const to call val_int(). This should be OK for
      a basic constant.
    */
    Item *item= (Item*) arg;
    return item->val_int() == value && item->unsigned_flag == unsigned_flag;
  }
  return FALSE;
}


5408
Item *Item_int_with_ref::clone_item()
5409
{
5410
  DBUG_ASSERT(ref->const_item());
5411 5412 5413 5414 5415 5416 5417 5418 5419 5420
  /*
    We need to evaluate the constant to make sure it works with
    parameter markers.
  */
  return (ref->unsigned_flag ?
          new Item_uint(ref->name, ref->val_int(), ref->max_length) :
          new Item_int(ref->name, ref->val_int(), ref->max_length));
}


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Item_num *Item_uint::neg()
{
5423
  Item_decimal *item= new Item_decimal(value, 1);
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  return item->neg();
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}
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5427

5428 5429 5430 5431 5432 5433 5434 5435 5436 5437 5438 5439 5440 5441 5442 5443 5444 5445 5446 5447 5448 5449 5450
static uint nr_of_decimals(const char *str, const char *end)
{
  const char *decimal_point;

  /* Find position for '.' */
  for (;;)
  {
    if (str == end)
      return 0;
    if (*str == 'e' || *str == 'E')
      return NOT_FIXED_DEC;    
    if (*str++ == '.')
      break;
  }
  decimal_point= str;
  for (; my_isdigit(system_charset_info, *str) ; str++)
    ;
  if (*str == 'e' || *str == 'E')
    return NOT_FIXED_DEC;
  return (uint) (str - decimal_point);
}


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5451
/**
5452 5453 5454 5455 5456 5457 5458 5459 5460 5461 5462
  This function is only called during parsing:
  - when parsing SQL query from sql_yacc.yy
  - when parsing XPath query from item_xmlfunc.cc
  We will signal an error if value is not a true double value (overflow):
  eng: Illegal %s '%-.192s' value found during parsing
  
  Note: the string is NOT null terminated when called from item_xmlfunc.cc,
  so this->name will contain some SQL query tail behind the "length" bytes.
  This is Ok for now, as this Item is never seen in SHOW,
  or EXPLAIN, or anywhere else in metadata.
  Item->name should be fixed to use LEX_STRING eventually.
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*/

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Item_float::Item_float(const char *str_arg, uint length)
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{
  int error;
5468 5469 5470
  char *end_not_used;
  value= my_strntod(&my_charset_bin, (char*) str_arg, length, &end_not_used,
                    &error);
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5471 5472
  if (error)
  {
5473 5474 5475
    char tmp[NAME_LEN + 1];
    my_snprintf(tmp, sizeof(tmp), "%.*s", length, str_arg);
    my_error(ER_ILLEGAL_VALUE_FOR_TYPE, MYF(0), "double", tmp);
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5476 5477
  }
  presentation= name=(char*) str_arg;
5478
  decimals=(uint8) nr_of_decimals(str_arg, str_arg+length);
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  max_length=length;
  fixed= 1;
}


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5484
int Item_float::save_in_field(Field *field, bool no_conversions)
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5485
{
5486
  double nr= val_real();
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5487 5488 5489
  if (null_value)
    return set_field_to_null(field);
  field->set_notnull();
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5490
  return field->store(nr);
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}

5493

5494
void Item_float::print(String *str, enum_query_type query_type)
5495 5496 5497 5498 5499 5500 5501 5502
{
  if (presentation)
  {
    str->append(presentation);
    return;
  }
  char buffer[20];
  String num(buffer, sizeof(buffer), &my_charset_bin);
5503
  num.set_real(value, decimals, &my_charset_bin);
5504 5505 5506 5507
  str->append(num);
}


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5508 5509 5510 5511 5512
/*
  hex item
  In string context this is a binary string.
  In number context this is a longlong value.
*/
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5513

5514
bool Item_float::eq(const Item *arg, bool binary_cmp) const
5515 5516 5517 5518 5519 5520 5521 5522
{
  if (arg->basic_const_item() && arg->type() == type())
  {
    /*
      We need to cast off const to call val_int(). This should be OK for
      a basic constant.
    */
    Item *item= (Item*) arg;
5523
    return item->val_real() == value;
5524 5525 5526 5527
  }
  return FALSE;
}

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5528

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5529
inline uint char_val(char X)
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{
  return (uint) (X >= '0' && X <= '9' ? X-'0' :
		 X >= 'A' && X <= 'Z' ? X-'A'+10 :
		 X-'a'+10);
}

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Georgi Kodinov committed
5536 5537 5538 5539
Item_hex_string::Item_hex_string()
{
  hex_string_init("", 0);
}
5540

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5541
Item_hex_string::Item_hex_string(const char *str, uint str_length)
Georgi Kodinov's avatar
Georgi Kodinov committed
5542 5543 5544 5545 5546
{
  hex_string_init(str, str_length);
}

void Item_hex_string::hex_string_init(const char *str, uint str_length)
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{
  max_length=(str_length+1)/2;
  char *ptr=(char*) sql_alloc(max_length+1);
  if (!ptr)
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Georgi Kodinov committed
5551 5552
  {
    str_value.set("", 0, &my_charset_bin);
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    return;
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Georgi Kodinov committed
5554
  }
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  str_value.set(ptr,max_length,&my_charset_bin);
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  char *end=ptr+max_length;
  if (max_length*2 != str_length)
    *ptr++=char_val(*str++);			// Not even, assume 0 prefix
  while (ptr != end)
  {
    *ptr++= (char) (char_val(str[0])*16+char_val(str[1]));
    str+=2;
  }
  *ptr=0;					// Keep purify happy
5565
  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
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5566
  fixed= 1;
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  unsigned_flag= 1;
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}

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longlong Item_hex_string::val_int()
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5571
{
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5572
  // following assert is redundant, because fixed=1 assigned in constructor
5573
  DBUG_ASSERT(fixed == 1);
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  char *end=(char*) str_value.ptr()+str_value.length(),
       *ptr=end-min(str_value.length(),sizeof(longlong));

  ulonglong value=0;
  for (; ptr != end ; ptr++)
    value=(value << 8)+ (ulonglong) (uchar) *ptr;
  return (longlong) value;
}


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my_decimal *Item_hex_string::val_decimal(my_decimal *decimal_value)
{
  // following assert is redundant, because fixed=1 assigned in constructor
  DBUG_ASSERT(fixed == 1);
  ulonglong value= (ulonglong)val_int();
  int2my_decimal(E_DEC_FATAL_ERROR, value, TRUE, decimal_value);
  return (decimal_value);
}


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5594
int Item_hex_string::save_in_field(Field *field, bool no_conversions)
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5595 5596 5597
{
  field->set_notnull();
  if (field->result_type() == STRING_RESULT)
5598 5599 5600 5601 5602
    return field->store(str_value.ptr(), str_value.length(), 
                        collation.collation);

  ulonglong nr;
  uint32 length= str_value.length();
5603 5604 5605
  if (!length)
    return 1;

5606
  if (length > 8)
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5607
  {
5608 5609
    nr= field->flags & UNSIGNED_FLAG ? ULONGLONG_MAX : LONGLONG_MAX;
    goto warn;
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5610
  }
5611 5612
  nr= (ulonglong) val_int();
  if ((length == 8) && !(field->flags & UNSIGNED_FLAG) && (nr > LONGLONG_MAX))
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5613
  {
5614 5615
    nr= LONGLONG_MAX;
    goto warn;
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  }
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  return field->store((longlong) nr, TRUE);  // Assume hex numbers are unsigned
5618 5619

warn:
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  if (!field->store((longlong) nr, TRUE))
5621 5622 5623
    field->set_warning(MYSQL_ERROR::WARN_LEVEL_WARN, ER_WARN_DATA_OUT_OF_RANGE,
                       1);
  return 1;
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}


5627
void Item_hex_string::print(String *str, enum_query_type query_type)
5628 5629 5630 5631 5632 5633 5634 5635 5636 5637 5638 5639
{
  char *end= (char*) str_value.ptr() + str_value.length(),
       *ptr= end - min(str_value.length(), sizeof(longlong));
  str->append("0x");
  for (; ptr != end ; ptr++)
  {
    str->append(_dig_vec_lower[((uchar) *ptr) >> 4]);
    str->append(_dig_vec_lower[((uchar) *ptr) & 0x0F]);
  }
}


5640
bool Item_hex_string::eq(const Item *arg, bool binary_cmp) const
5641 5642 5643 5644 5645 5646 5647 5648 5649 5650
{
  if (arg->basic_const_item() && arg->type() == type())
  {
    if (binary_cmp)
      return !stringcmp(&str_value, &arg->str_value);
    return !sortcmp(&str_value, &arg->str_value, collation.collation);
  }
  return FALSE;
}

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5651

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5652
Item *Item_hex_string::safe_charset_converter(CHARSET_INFO *tocs)
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{
  Item_string *conv;
  String tmp, *str= val_str(&tmp);

  if (!(conv= new Item_string(str->ptr(), str->length(), tocs)))
    return NULL;
  conv->str_value.copy();
5660
  conv->str_value.mark_as_const();
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  return conv;
}


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5665 5666 5667 5668 5669 5670 5671 5672 5673 5674 5675 5676 5677 5678 5679 5680 5681
/*
  bin item.
  In string context this is a binary string.
  In number context this is a longlong value.
*/
  
Item_bin_string::Item_bin_string(const char *str, uint str_length)
{
  const char *end= str + str_length - 1;
  uchar bits= 0;
  uint power= 1;

  max_length= (str_length + 7) >> 3;
  char *ptr= (char*) sql_alloc(max_length + 1);
  if (!ptr)
    return;
  str_value.set(ptr, max_length, &my_charset_bin);
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5682 5683

  if (max_length > 0)
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  {
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    ptr+= max_length - 1;
    ptr[1]= 0;                     // Set end null for string
    for (; end >= str; end--)
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5688
    {
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5689 5690 5691 5692 5693 5694 5695 5696 5697
      if (power == 256)
      {
        power= 1;
        *ptr--= bits;
        bits= 0;
      }
      if (*end == '1')
        bits|= power;
      power<<= 1;
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5698
    }
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5699
    *ptr= (char) bits;
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5700
  }
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5701 5702 5703
  else
    ptr[0]= 0;

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  collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
  fixed= 1;
}


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5709 5710
/**
  Pack data in buffer for sending.
5711 5712 5713
*/

bool Item_null::send(Protocol *protocol, String *packet)
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{
5715
  return protocol->store_null();
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}

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/**
  This is only called from items that is not of type item_field.
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*/

5722
bool Item::send(Protocol *protocol, String *buffer)
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{
5724
  bool UNINIT_VAR(result);                       // Will be set if null_value == 0
5725
  enum_field_types f_type;
5726

5727
  switch ((f_type=field_type())) {
5728
  default:
5729 5730 5731 5732 5733 5734 5735 5736 5737
  case MYSQL_TYPE_NULL:
  case MYSQL_TYPE_DECIMAL:
  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_GEOMETRY:
5738 5739
  case MYSQL_TYPE_STRING:
  case MYSQL_TYPE_VAR_STRING:
5740
  case MYSQL_TYPE_VARCHAR:
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5741
  case MYSQL_TYPE_BIT:
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5742
  case MYSQL_TYPE_NEWDECIMAL:
5743 5744 5745
  {
    String *res;
    if ((res=val_str(buffer)))
5746
      result= protocol->store(res->ptr(),res->length(),res->charset());
5747 5748 5749 5750
    else
    {
      DBUG_ASSERT(null_value);
    }
5751 5752 5753 5754 5755 5756 5757 5758 5759 5760 5761
    break;
  }
  case MYSQL_TYPE_TINY:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_tiny(nr);
    break;
  }
  case MYSQL_TYPE_SHORT:
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  case MYSQL_TYPE_YEAR:
5763 5764 5765 5766 5767 5768 5769
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_short(nr);
    break;
  }
5770
  case MYSQL_TYPE_INT24:
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  case MYSQL_TYPE_LONG:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_long(nr);
    break;
  }
  case MYSQL_TYPE_LONGLONG:
  {
    longlong nr;
    nr= val_int();
    if (!null_value)
      result= protocol->store_longlong(nr, unsigned_flag);
    break;
  }
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5787 5788 5789
  case MYSQL_TYPE_FLOAT:
  {
    float nr;
5790
    nr= (float) val_real();
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    if (!null_value)
      result= protocol->store(nr, decimals, buffer);
    break;
  }
5795 5796
  case MYSQL_TYPE_DOUBLE:
  {
5797
    double nr= val_real();
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    if (!null_value)
      result= protocol->store(nr, decimals, buffer);
    break;
  }
  case MYSQL_TYPE_DATETIME:
  case MYSQL_TYPE_DATE:
5804
  case MYSQL_TYPE_TIMESTAMP:
5805
  {
5806
    MYSQL_TIME tm;
5807
    get_date(&tm, TIME_FUZZY_DATE);
5808 5809
    if (!null_value)
    {
5810
      if (f_type == MYSQL_TYPE_DATE)
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	return protocol->store_date(&tm);
      else
	result= protocol->store(&tm);
    }
    break;
  }
  case MYSQL_TYPE_TIME:
  {
5819
    MYSQL_TIME tm;
5820 5821 5822 5823 5824 5825 5826 5827 5828
    get_time(&tm);
    if (!null_value)
      result= protocol->store_time(&tm);
    break;
  }
  }
  if (null_value)
    result= protocol->store_null();
  return result;
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}

5831 5832

bool Item_field::send(Protocol *protocol, String *buffer)
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5833
{
5834
  return protocol->store(result_field);
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}

5837

5838 5839 5840 5841 5842 5843 5844 5845 5846 5847 5848 5849 5850 5851 5852 5853
void Item_field::update_null_value() 
{ 
  /* 
    need to set no_errors to prevent warnings about type conversion 
    popping up.
  */
  THD *thd= field->table->in_use;
  int no_errors;

  no_errors= thd->no_errors;
  thd->no_errors= 1;
  Item::update_null_value();
  thd->no_errors= no_errors;
}


5854 5855 5856 5857 5858 5859 5860 5861 5862 5863 5864 5865 5866 5867 5868 5869 5870 5871 5872 5873 5874 5875
/*
  Add the field to the select list and substitute it for the reference to
  the field.

  SYNOPSIS
    Item_field::update_value_transformer()
    select_arg      current select

  DESCRIPTION
    If the field doesn't belong to the table being inserted into then it is
    added to the select list, pointer to it is stored in the ref_pointer_array
    of the select and the field itself is substituted for the Item_ref object.
    This is done in order to get correct values from update fields that
    belongs to the SELECT part in the INSERT .. SELECT .. ON DUPLICATE KEY
    UPDATE statement.

  RETURN
    0             if error occured
    ref           if all conditions are met
    this field    otherwise
*/

5876
Item *Item_field::update_value_transformer(uchar *select_arg)
5877 5878 5879 5880 5881 5882 5883 5884 5885 5886 5887 5888 5889 5890 5891 5892 5893 5894 5895 5896 5897 5898
{
  SELECT_LEX *select= (SELECT_LEX*)select_arg;
  DBUG_ASSERT(fixed);

  if (field->table != select->context.table_list->table &&
      type() != Item::TRIGGER_FIELD_ITEM)
  {
    List<Item> *all_fields= &select->join->all_fields;
    Item **ref_pointer_array= select->ref_pointer_array;
    int el= all_fields->elements;
    Item_ref *ref;

    ref_pointer_array[el]= (Item*)this;
    all_fields->push_front((Item*)this);
    ref= new Item_ref(&select->context, ref_pointer_array + el,
                      table_name, field_name);
    return ref;
  }
  return this;
}


5899
void Item_field::print(String *str, enum_query_type query_type)
5900 5901 5902 5903 5904 5905
{
  if (field && field->table->const_table)
  {
    char buff[MAX_FIELD_WIDTH];
    String tmp(buff,sizeof(buff),str->charset());
    field->val_str(&tmp);
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    if (field->is_null())
      str->append("NULL");
    else
    {
      str->append('\'');
      str->append(tmp);
      str->append('\'');
    }
5914 5915
    return;
  }
5916
  Item_ident::print(str, query_type);
5917 5918 5919
}


5920 5921
Item_ref::Item_ref(Name_resolution_context *context_arg,
                   Item **item, const char *table_name_arg,
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                   const char *field_name_arg,
                   bool alias_name_used_arg)
5924
  :Item_ident(context_arg, NullS, table_name_arg, field_name_arg),
5925
   result_field(0), ref(item), reference_trough_name(0)
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{
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  alias_name_used= alias_name_used_arg;
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  /*
    This constructor used to create some internals references over fixed items
  */
5931
  if (ref && *ref && (*ref)->fixed)
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    set_properties();
}

5935 5936 5937 5938 5939 5940 5941 5942 5943 5944 5945 5946 5947 5948 5949 5950 5951 5952 5953 5954 5955 5956 5957 5958 5959 5960 5961 5962 5963
/*
  A Field_enumerator-compatible class that invokes mark_as_dependent() for
  each field that is a reference to some ancestor of current_select.
*/
class Dependency_marker: public Field_enumerator
{
public:
  THD *thd;
  st_select_lex *current_select;
  virtual void visit_field(Item_field *item)
  {
    // Find which select the field is in. This is achieved by walking up 
    // the select tree and looking for the table of interest.
    st_select_lex *sel;
    for (sel= current_select; sel; sel= sel->outer_select())
    {
      TABLE_LIST *tbl;
      for (tbl= sel->leaf_tables; tbl; tbl= tbl->next_leaf)
      {
        if (tbl->table == item->field->table)
        {
          if (sel != current_select)
            mark_as_dependent(thd, sel, current_select, item, item);
          return;
        }
      }
    }
  }
};
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5964

5965 5966 5967
Item_ref::Item_ref(TABLE_LIST *view_arg, Item **item,
                   const char *field_name_arg, bool alias_name_used_arg)
  :Item_ident(view_arg, field_name_arg),
5968
   result_field(NULL), ref(item), reference_trough_name(0)
5969 5970 5971 5972 5973 5974 5975 5976 5977 5978
{
  alias_name_used= alias_name_used_arg;
  /*
    This constructor is used to create some internal references over fixed items
  */
  if (ref && *ref && (*ref)->fixed)
    set_properties();
}


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5979
/**
5980
  Resolve the name of a reference to a column reference.
5981

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5982 5983 5984 5985
  The method resolves the column reference represented by 'this' as a column
  present in one of: GROUP BY clause, SELECT clause, outer queries. It is
  used typically for columns in the HAVING clause which are not under
  aggregate functions.
5986

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5987 5988
  POSTCONDITION @n
  Item_ref::ref is 0 or points to a valid item.
5989

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  @note
5991 5992
    The name resolution algorithm used is (where [T_j] is an optional table
    name that qualifies the column name):
5993

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5994 5995
  @code
        resolve_extended([T_j].col_ref_i)
5996
        {
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          Search for a column or derived column named col_ref_i [in table T_j]
          in the SELECT and GROUP clauses of Q.
5999

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6000 6001 6002 6003 6004 6005 6006 6007 6008 6009 6010 6011 6012 6013 6014 6015 6016
          if such a column is NOT found AND    // Lookup in outer queries.
             there are outer queries
          {
            for each outer query Q_k beginning from the inner-most one
           {
              Search for a column or derived column named col_ref_i
              [in table T_j] in the SELECT and GROUP clauses of Q_k.

              if such a column is not found AND
                 - Q_k is not a group query AND
                 - Q_k is not inside an aggregate function
                 OR
                 - Q_(k-1) is not in a HAVING or SELECT clause of Q_k
              {
                search for a column or derived column named col_ref_i
                [in table T_j] in the FROM clause of Q_k;
              }
6017 6018 6019
            }
          }
        }
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6020 6021
  @endcode
  @n
6022
    This procedure treats GROUP BY and SELECT clauses as one namespace for
6023 6024 6025
    column references in HAVING. Notice that compared to
    Item_field::fix_fields, here we first search the SELECT and GROUP BY
    clauses, and then we search the FROM clause.
6026

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  @param[in]     thd        current thread
  @param[in,out] reference  view column if this item was resolved to a
    view column
6030

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  @todo
    Here we could first find the field anyway, and then test this
    condition, so that we can give a better error message -
    ER_WRONG_FIELD_WITH_GROUP, instead of the less informative
    ER_BAD_FIELD_ERROR which we produce now.

  @retval
6038
    TRUE  if error
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6039
  @retval
6040 6041
    FALSE on success
*/
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6042

6043
bool Item_ref::fix_fields(THD *thd, Item **reference)
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6044
{
6045
  enum_parsing_place place= NO_MATTER;
6046
  DBUG_ASSERT(fixed == 0);
6047 6048
  SELECT_LEX *current_sel= thd->lex->current_select;

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6049
  if (!ref || ref == not_found_item)
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6050
  {
6051
    DBUG_ASSERT(reference_trough_name != 0);
6052 6053 6054
    if (!(ref= resolve_ref_in_select_and_group(thd, this,
                                               context->select_lex)))
      goto error;             /* Some error occurred (e.g. ambiguous names). */
6055

6056
    if (ref == not_found_item) /* This reference was not resolved. */
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6057
    {
6058 6059
      Name_resolution_context *last_checked_context= context;
      Name_resolution_context *outer_context= context->outer_context;
6060 6061 6062
      Field *from_field;
      ref= 0;

6063
      if (!outer_context)
6064 6065 6066 6067
      {
        /* The current reference cannot be resolved in this query. */
        my_error(ER_BAD_FIELD_ERROR,MYF(0),
                 this->full_name(), current_thd->where);
6068
        goto error;
6069
      }
6070

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6071
      /*
6072 6073 6074
        If there is an outer context (select), and it is not a derived table
        (which do not support the use of outer fields for now), try to
        resolve this reference in the outer select(s).
6075

6076 6077 6078
        We treat each subselect as a separate namespace, so that different
        subselects may contain columns with the same names. The subselects are
        searched starting from the innermost.
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6079
      */
6080 6081
      from_field= (Field*) not_found_field;

6082
      do
6083
      {
6084 6085 6086 6087
        SELECT_LEX *select= outer_context->select_lex;
        Item_subselect *prev_subselect_item=
          last_checked_context->select_lex->master_unit()->item;
        last_checked_context= outer_context;
6088

6089
        /* Search in the SELECT and GROUP lists of the outer select. */
6090
        if (outer_context->resolve_in_select_list)
6091
        {
6092 6093
          if (!(ref= resolve_ref_in_select_and_group(thd, this, select)))
            goto error; /* Some error occurred (e.g. ambiguous names). */
6094
          if (ref != not_found_item)
6095
          {
6096 6097 6098 6099
            DBUG_ASSERT(*ref && (*ref)->fixed);
            prev_subselect_item->used_tables_cache|= (*ref)->used_tables();
            prev_subselect_item->const_item_cache&= (*ref)->const_item();
            break;
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          }
          /*
6102 6103 6104
            Set ref to 0 to ensure that we get an error in case we replaced
            this item with another item and still use this item in some
            other place of the parse tree.
6105
          */
6106
          ref= 0;
6107
        }
6108

6109 6110 6111 6112 6113
        place= prev_subselect_item->parsing_place;
        /*
          Check table fields only if the subquery is used somewhere out of
          HAVING or the outer SELECT does not use grouping (i.e. tables are
          accessible).
6114
          TODO:
6115 6116 6117 6118 6119 6120
          Here we could first find the field anyway, and then test this
          condition, so that we can give a better error message -
          ER_WRONG_FIELD_WITH_GROUP, instead of the less informative
          ER_BAD_FIELD_ERROR which we produce now.
        */
        if ((place != IN_HAVING ||
6121 6122
             (!select->with_sum_func &&
              select->group_list.elements == 0)))
6123
        {
6124
          /*
6125 6126 6127
            In case of view, find_field_in_tables() write pointer to view
            field expression to 'reference', i.e. it substitute that
            expression instead of this Item_ref
6128
          */
6129
          from_field= find_field_in_tables(thd, this,
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6130 6131 6132 6133
                                           outer_context->
                                             first_name_resolution_table,
                                           outer_context->
                                             last_name_resolution_table,
6134 6135
                                           reference,
                                           IGNORE_EXCEPT_NON_UNIQUE,
6136
                                           TRUE, TRUE);
6137
          if (! from_field)
6138
            goto error;
6139
          if (from_field == view_ref_found)
6140
          {
6141
            Item::Type refer_type= (*reference)->type();
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            prev_subselect_item->used_tables_cache|=
              (*reference)->used_tables();
            prev_subselect_item->const_item_cache&=
              (*reference)->const_item();
            DBUG_ASSERT((*reference)->type() == REF_ITEM);
6147 6148
            mark_as_dependent(thd, last_checked_context->select_lex,
                              context->select_lex, this,
6149 6150
                              ((refer_type == REF_ITEM ||
                                refer_type == FIELD_ITEM) ?
6151 6152
                               (Item_ident*) (*reference) :
                               0));
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6153 6154 6155
           context->select_lex->
              register_dependency_item(last_checked_context->select_lex,
                                       reference);
6156 6157 6158 6159
            /*
              view reference found, we substituted it instead of this
              Item, so can quit
            */
6160 6161
            return FALSE;
          }
6162 6163
          if (from_field != not_found_field)
          {
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            if (cached_table && cached_table->select_lex &&
                outer_context->select_lex &&
                cached_table->select_lex != outer_context->select_lex)
            {
              /*
                Due to cache, find_field_in_tables() can return field which
                doesn't belong to provided outer_context. In this case we have
                to find proper field context in order to fix field correcly.
              */
              do
              {
                outer_context= outer_context->outer_context;
                select= outer_context->select_lex;
                prev_subselect_item=
                  last_checked_context->select_lex->master_unit()->item;
                last_checked_context= outer_context;
              } while (outer_context && outer_context->select_lex &&
                       cached_table->select_lex != outer_context->select_lex);
            }
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            prev_subselect_item->used_tables_cache|= from_field->table->map;
            prev_subselect_item->const_item_cache= 0;
            break;
          }
6187
        }
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        DBUG_ASSERT(from_field == not_found_field);

        /* Reference is not found => depend on outer (or just error). */
        prev_subselect_item->used_tables_cache|= OUTER_REF_TABLE_BIT;
        prev_subselect_item->const_item_cache= 0;

6194 6195
        outer_context= outer_context->outer_context;
      } while (outer_context);
6196 6197 6198

      DBUG_ASSERT(from_field != 0 && from_field != view_ref_found);
      if (from_field != not_found_field)
6199
      {
6200 6201
        Item_field* fld;
        if (!(fld= new Item_field(from_field)))
6202
          goto error;
6203
        thd->change_item_tree(reference, fld);
6204
        mark_as_dependent(thd, last_checked_context->select_lex,
6205
                          thd->lex->current_select, fld, fld);
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        context->select_lex->
              register_dependency_item(last_checked_context->select_lex,
                                       reference);
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        /*
          A reference is resolved to a nest level that's outer or the same as
          the nest level of the enclosing set function : adjust the value of
          max_arg_level for the function if it's needed.
        */
        if (thd->lex->in_sum_func &&
            thd->lex->in_sum_func->nest_level >= 
            last_checked_context->select_lex->nest_level)
          set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                        last_checked_context->select_lex->nest_level);
6219 6220 6221 6222 6223 6224
        return FALSE;
      }
      if (ref == 0)
      {
        /* The item was not a table field and not a reference */
        my_error(ER_BAD_FIELD_ERROR, MYF(0),
6225
                 this->full_name(), current_thd->where);
6226
        goto error;
6227
      }
6228 6229
      /* Should be checked in resolve_ref_in_select_and_group(). */
      DBUG_ASSERT(*ref && (*ref)->fixed);
6230 6231
      mark_as_dependent(thd, last_checked_context->select_lex,
                        context->select_lex, this, this);
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6232 6233 6234
      context->select_lex->
              register_dependency_item(last_checked_context->select_lex,
                                       reference);
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6235 6236 6237 6238 6239 6240 6241 6242 6243 6244
      /*
        A reference is resolved to a nest level that's outer or the same as
        the nest level of the enclosing set function : adjust the value of
        max_arg_level for the function if it's needed.
      */
      if (thd->lex->in_sum_func &&
          thd->lex->in_sum_func->nest_level >= 
          last_checked_context->select_lex->nest_level)
        set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                      last_checked_context->select_lex->nest_level);
6245
    }
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6246
  }
6247 6248
  else
  {
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6249 6250 6251 6252 6253
    if (depended_from && reference)
    {
      DBUG_ASSERT(context->select_lex != depended_from);
      context->select_lex->register_dependency_item(depended_from, reference);
    }
6254 6255 6256 6257 6258 6259 6260 6261 6262 6263 6264
    /*
      It could be that we're referring to something that's in ancestor selects.
      We must make an appropriate mark_as_dependent() call for each such
      outside reference.
    */
    Dependency_marker dep_marker;
    dep_marker.current_select= current_sel;
    dep_marker.thd= thd;
    (*ref)->walk(&Item::enumerate_field_refs_processor, FALSE,
                 (uchar*)&dep_marker);
  }
6265

6266
  DBUG_ASSERT(*ref);
6267
  /*
6268
    Check if this is an incorrect reference in a group function or forward
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6269 6270 6271
    reference. Do not issue an error if this is:
      1. outer reference (will be fixed later by the fix_inner_refs function);
      2. an unnamed reference inside an aggregate function.
6272
  */
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6273 6274 6275 6276 6277 6278
  if (!((*ref)->type() == REF_ITEM &&
       ((Item_ref *)(*ref))->ref_type() == OUTER_REF) &&
      (((*ref)->with_sum_func && name &&
        !(current_sel->linkage != GLOBAL_OPTIONS_TYPE &&
          current_sel->having_fix_field)) ||
       !(*ref)->fixed))
6279
  {
6280 6281 6282 6283
    my_error(ER_ILLEGAL_REFERENCE, MYF(0),
             name, ((*ref)->with_sum_func?
                    "reference to group function":
                    "forward reference in item list"));
6284
    goto error;
6285
  }
6286 6287 6288

  set_properties();

6289
  if ((*ref)->check_cols(1))
6290
    goto error;
6291
  return FALSE;
6292 6293 6294 6295

error:
  context->process_error(thd);
  return TRUE;
6296 6297
}

6298

6299 6300
void Item_ref::set_properties()
{
6301 6302 6303
  max_length= (*ref)->max_length;
  maybe_null= (*ref)->maybe_null;
  decimals=   (*ref)->decimals;
6304
  collation.set((*ref)->collation);
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6305 6306 6307 6308
  /*
    We have to remember if we refer to a sum function, to ensure that
    split_sum_func() doesn't try to change the reference.
  */
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6309
  with_sum_func= (*ref)->with_sum_func;
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6310
  with_field= (*ref)->with_field;
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6311
  unsigned_flag= (*ref)->unsigned_flag;
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6312 6313 6314
  fixed= 1;
  if (alias_name_used)
    return;
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6315 6316 6317 6318
  if ((*ref)->type() == FIELD_ITEM)
    alias_name_used= ((Item_ident *) (*ref))->alias_name_used;
  else
    alias_name_used= TRUE; // it is not field, so it is was resolved by alias
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6319 6320
}

6321

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6322 6323
void Item_ref::cleanup()
{
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6324
  DBUG_ENTER("Item_ref::cleanup");
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6325
  Item_ident::cleanup();
6326
  result_field= 0;
6327 6328 6329 6330 6331
  if (reference_trough_name)
  {
    /* We have to reset the reference as it may been freed */
    ref= 0;
  }
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6332
  DBUG_VOID_RETURN;
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6333 6334 6335
}


6336 6337 6338 6339 6340 6341 6342 6343 6344 6345 6346 6347 6348 6349 6350 6351 6352 6353 6354 6355 6356 6357 6358 6359 6360 6361 6362 6363 6364 6365 6366 6367 6368 6369 6370 6371 6372 6373 6374 6375 6376 6377 6378 6379 6380 6381 6382 6383 6384 6385 6386 6387 6388 6389 6390 6391 6392 6393 6394 6395 6396 6397 6398 6399 6400 6401 6402 6403 6404 6405
/**
  Transform an Item_ref object with a transformer callback function.

  The function first applies the transform method to the item
  referenced by this Item_reg object. If this returns a new item the
  old item is substituted for a new one. After this the transformer
  is applied to the Item_ref object.

  @param transformer   the transformer callback function to be applied to
                       the nodes of the tree of the object
  @param argument      parameter to be passed to the transformer

  @return Item returned as the result of transformation of the Item_ref object
    @retval !NULL The transformation was successful
    @retval NULL  Out of memory error
*/

Item* Item_ref::transform(Item_transformer transformer, uchar *arg)
{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());
  DBUG_ASSERT((*ref) != NULL);

  /* Transform the object we are referencing. */
  Item *new_item= (*ref)->transform(transformer, arg);
  if (!new_item)
    return NULL;

  /*
    THD::change_item_tree() should be called only if the tree was
    really transformed, i.e. when a new item has been created.
    Otherwise we'll be allocating a lot of unnecessary memory for
    change records at each execution.
  */
  if (*ref != new_item)
    current_thd->change_item_tree(ref, new_item);

  /* Transform the item ref object. */
  return (this->*transformer)(arg);
}


/**
  Compile an Item_ref object with a processor and a transformer
  callback functions.

  First the function applies the analyzer to the Item_ref object. Then
  if the analizer succeeeds we first applies the compile method to the
  object the Item_ref object is referencing.  If this returns a new
  item the old item is substituted for a new one.  After this the
  transformer is applied to the Item_ref object itself.

  @param analyzer      the analyzer callback function to be applied to the
                       nodes of the tree of the object
  @param[in,out] arg_p parameter to be passed to the processor
  @param transformer   the transformer callback function to be applied to the
                       nodes of the tree of the object
  @param arg_t         parameter to be passed to the transformer

  @return Item returned as the result of transformation of the Item_ref object
*/

Item* Item_ref::compile(Item_analyzer analyzer, uchar **arg_p,
                        Item_transformer transformer, uchar *arg_t)
{
  /* Analyze this Item object. */
  if (!(this->*analyzer)(arg_p))
    return NULL;

  /* Compile the Item we are referencing. */
  DBUG_ASSERT((*ref) != NULL);
6406 6407
  uchar *arg_v= *arg_p;
  Item *new_item= (*ref)->compile(analyzer, &arg_v, transformer, arg_t);
6408 6409
  if (new_item && *ref != new_item)
    current_thd->change_item_tree(ref, new_item);
6410

6411 6412 6413 6414 6415
  /* Transform this Item object. */
  return (this->*transformer)(arg_t);
}


6416
void Item_ref::print(String *str, enum_query_type query_type)
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6417
{
6418
  if (ref)
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6419 6420
  {
    if ((*ref)->type() != Item::CACHE_ITEM && ref_type() != VIEW_REF &&
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6421
        !table_name && name && alias_name_used)
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6422 6423
    {
      THD *thd= current_thd;
6424 6425
      append_identifier(thd, str, (*ref)->real_item()->name,
                        (*ref)->real_item()->name_length);
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6426 6427
    }
    else
6428
      (*ref)->print(str, query_type);
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6429
  }
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6430
  else
6431
    Item_ident::print(str, query_type);
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}


6435 6436 6437 6438 6439 6440 6441 6442
bool Item_ref::send(Protocol *prot, String *tmp)
{
  if (result_field)
    return prot->store(result_field);
  return (*ref)->send(prot, tmp);
}


6443 6444 6445 6446 6447 6448 6449 6450
double Item_ref::val_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0.0;
    return result_field->val_real();
  }
6451
  return val_real();
6452 6453 6454
}


6455 6456 6457 6458 6459 6460 6461 6462 6463
bool Item_ref::is_null_result()
{
  if (result_field)
    return (null_value=result_field->is_null());

  return is_null();
}


6464 6465 6466 6467 6468
longlong Item_ref::val_int_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
6469
      return 0;
6470 6471 6472 6473 6474 6475 6476 6477 6478 6479 6480 6481 6482 6483 6484 6485 6486 6487 6488
    return result_field->val_int();
  }
  return val_int();
}


String *Item_ref::str_result(String* str)
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
    str->set_charset(str_value.charset());
    return result_field->val_str(str, &str_value);
  }
  return val_str(str);
}


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my_decimal *Item_ref::val_decimal_result(my_decimal *decimal_value)
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
    return result_field->val_decimal(decimal_value);
  }
  return val_decimal(decimal_value);
}


bool Item_ref::val_bool_result()
{
  if (result_field)
  {
    if ((null_value= result_field->is_null()))
      return 0;
6507
    switch (result_field->result_type()) {
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6508
    case INT_RESULT:
6509
      return result_field->val_int() != 0;
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    case DECIMAL_RESULT:
6511 6512 6513 6514 6515 6516 6517
    {
      my_decimal decimal_value;
      my_decimal *val= result_field->val_decimal(&decimal_value);
      if (val)
        return !my_decimal_is_zero(val);
      return 0;
    }
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    case REAL_RESULT:
    case STRING_RESULT:
      return result_field->val_real() != 0.0;
    case ROW_RESULT:
    default:
      DBUG_ASSERT(0);
    }
  }
  return val_bool();
}


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void Item_ref::save_result(Field *to)
{
  if (result_field)
  {
    save_field_in_field(result_field, &null_value, to, TRUE);
    return;
  }
  (*ref)->save_result(to);
  null_value= (*ref)->null_value;
}


void Item_ref::save_val(Field *to)
{
  (*ref)->save_result(to);
  null_value= (*ref)->null_value;
}


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double Item_ref::val_real()
{
  DBUG_ASSERT(fixed);
  double tmp=(*ref)->val_result();
  null_value=(*ref)->null_value;
  return tmp;
}


longlong Item_ref::val_int()
{
  DBUG_ASSERT(fixed);
  longlong tmp=(*ref)->val_int_result();
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_ref::val_bool()
{
  DBUG_ASSERT(fixed);
  bool tmp= (*ref)->val_bool_result();
  null_value= (*ref)->null_value;
  return tmp;
}


String *Item_ref::val_str(String* tmp)
{
  DBUG_ASSERT(fixed);
  tmp=(*ref)->str_result(tmp);
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_ref::is_null()
{
  DBUG_ASSERT(fixed);
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  bool tmp=(*ref)->is_null_result();
  null_value=(*ref)->null_value;
  return tmp;
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}


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bool Item_ref::get_date(MYSQL_TIME *ltime,uint fuzzydate)
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{
  return (null_value=(*ref)->get_date_result(ltime,fuzzydate));
}


my_decimal *Item_ref::val_decimal(my_decimal *decimal_value)
{
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  my_decimal *val= (*ref)->val_decimal_result(decimal_value);
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  null_value= (*ref)->null_value;
  return val;
}

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int Item_ref::save_in_field(Field *to, bool no_conversions)
{
  int res;
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  DBUG_ASSERT(!result_field);
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  res= (*ref)->save_in_field(to, no_conversions);
  null_value= (*ref)->null_value;
  return res;
}

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void Item_ref::save_org_in_field(Field *field)
{
  (*ref)->save_org_in_field(field);
}


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void Item_ref::make_field(Send_field *field)
{
  (*ref)->make_field(field);
  /* Non-zero in case of a view */
  if (name)
    field->col_name= name;
  if (table_name)
    field->table_name= table_name;
  if (db_name)
    field->db_name= db_name;
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  if (orig_field_name)
    field->org_col_name= orig_field_name;
  if (orig_table_name)
    field->org_table_name= orig_table_name;
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}
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Item *Item_ref::get_tmp_table_item(THD *thd)
{
  if (!result_field)
    return (*ref)->get_tmp_table_item(thd);

  Item_field *item= new Item_field(result_field);
  if (item)
  {
    item->table_name= table_name;
    item->db_name= db_name;
  }
  return item;
}


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void Item_ref_null_helper::print(String *str, enum_query_type query_type)
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{
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  str->append(STRING_WITH_LEN("<ref_null_helper>("));
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  if (ref)
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    (*ref)->print(str, query_type);
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  else
    str->append('?');
  str->append(')');
}


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void Item_direct_ref::save_val(Field *to)
{
  (*ref)->save_val(to);
  null_value=(*ref)->null_value;
}


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double Item_direct_ref::val_real()
{
  double tmp=(*ref)->val_real();
  null_value=(*ref)->null_value;
  return tmp;
}


longlong Item_direct_ref::val_int()
{
  longlong tmp=(*ref)->val_int();
  null_value=(*ref)->null_value;
  return tmp;
}


String *Item_direct_ref::val_str(String* tmp)
{
  tmp=(*ref)->val_str(tmp);
  null_value=(*ref)->null_value;
  return tmp;
}


my_decimal *Item_direct_ref::val_decimal(my_decimal *decimal_value)
{
  my_decimal *tmp= (*ref)->val_decimal(decimal_value);
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_direct_ref::val_bool()
{
  bool tmp= (*ref)->val_bool();
  null_value=(*ref)->null_value;
  return tmp;
}


bool Item_direct_ref::is_null()
{
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  return (*ref)->is_null();
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}


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bool Item_direct_ref::get_date(MYSQL_TIME *ltime,uint fuzzydate)
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{
  return (null_value=(*ref)->get_date(ltime,fuzzydate));
}


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Item* Item_direct_ref_to_ident::transform(Item_transformer transformer,
                                          uchar *argument)
{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());

  Item *new_item= ident->transform(transformer, argument);
  if (!new_item)
    return 0;
  DBUG_ASSERT(new_item->type() == FIELD_ITEM || new_item->type() == REF_ITEM);

  if (ident != new_item)
    current_thd->change_item_tree((Item**)&ident, new_item);
  return (this->*transformer)(argument);
}


Item* Item_direct_ref_to_ident::compile(Item_analyzer analyzer, uchar **arg_p,
                                        Item_transformer transformer,
                                        uchar *arg_t)
{
  if (!(this->*analyzer)(arg_p))
    return 0;

  uchar *arg_v= *arg_p;
  Item *new_item= ident->compile(analyzer, &arg_v, transformer, arg_t);
  if (new_item && ident != new_item)
  {
    DBUG_ASSERT(new_item->type() == FIELD_ITEM || new_item->type() == REF_ITEM);
    current_thd->change_item_tree((Item**)&ident, new_item);
  }
  return (this->*transformer)(arg_t);
}


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Item_cache_wrapper::~Item_cache_wrapper()
{
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  DBUG_ASSERT(expr_cache == 0);
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}


Item_cache_wrapper::Item_cache_wrapper(Item *item_arg)
:orig_item(item_arg), expr_cache(NULL), expr_value(NULL)
{
  DBUG_ASSERT(orig_item->fixed);
  max_length= orig_item->max_length;
  maybe_null= orig_item->maybe_null;
  decimals=   orig_item->decimals;
  collation.set(orig_item->collation);
  with_sum_func= orig_item->with_sum_func;
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  with_field= orig_item->with_field;
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  unsigned_flag= orig_item->unsigned_flag;
  name= item_arg->name;
  name_length= item_arg->name_length;

  if ((expr_value= Item_cache::get_cache(orig_item)))
    expr_value->setup(orig_item);

  fixed= 1;
}


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void Item_cache_wrapper::print(String *str, enum_query_type query_type)
{
  str->append(func_name());
  if (expr_cache)
    expr_cache->print(str, query_type);
  else
    str->append(STRING_WITH_LEN("<<DISABLED>>"));
  str->append('(');
  orig_item->print(str, query_type);
  str->append(')');
}


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/**
  Prepare the expression cache wrapper (do nothing)

  @retval FALSE OK
*/

bool Item_cache_wrapper::fix_fields(THD *thd  __attribute__((unused)),
                                    Item **it __attribute__((unused)))
{
  DBUG_ASSERT(orig_item->fixed);
  DBUG_ASSERT(fixed);
  return FALSE;
}


/**
  Clean the expression cache wrapper up before reusing it.
*/

void Item_cache_wrapper::cleanup()
{
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  DBUG_ENTER("Item_cache_wrapper::cleanup");
  Item_result_field::cleanup();
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  delete expr_cache;
  expr_cache= 0;
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  /* expr_value is Item so it will be destroyed from list of Items */
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  expr_value= 0;
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  DBUG_VOID_RETURN;
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}


/**
  Create an expression cache that uses a temporary table

  @param thd           Thread handle
  @param depends_on    Parameters of the expression to create cache for

  @details
  The function takes 'depends_on' as the list of all parameters for
  the expression wrapped into this object and creates an expression
  cache in a temporary table containing the field for the parameters
  and the result of the expression.

  @retval FALSE OK
  @retval TRUE  Error
*/

bool Item_cache_wrapper::set_cache(THD *thd, List<Item*> &depends_on)
{
  DBUG_ENTER("Item_cache_wrapper::set_cache");
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  DBUG_ASSERT(expr_cache == 0);
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  expr_cache= new Expression_cache_tmptable(thd, depends_on, expr_value);
  DBUG_RETURN(expr_cache == NULL);
}


/**
  Check if the current values of the parameters are in the expression cache

  @details
  The function checks whether the current set of the parameters of the
  referenced item can be found in the expression cache. If so the function
  returns the item by which the result of the expression can be easily
  extracted from the cache with the corresponding val_* method.

  @retval NULL    - parameters are not in the cache
  @retval <item*> - item providing the result of the expression found in cache
*/

Item *Item_cache_wrapper::check_cache()
{
  DBUG_ENTER("Item_cache_wrapper::check_cache");
  if (expr_cache)
  {
    Expression_cache_tmptable::result res;
    Item *cached_value;
    res= expr_cache->check_value(&cached_value);
    if (res == Expression_cache_tmptable::HIT)
      DBUG_RETURN(cached_value);
  }
  DBUG_RETURN(NULL);
}


/**
  Get the value of the cached expression and put it in the cache
*/

inline void Item_cache_wrapper::cache()
{
  expr_value->store(orig_item);
  expr_value->cache_value();
  expr_cache->put_value(expr_value); // put in expr_cache
}


/**
  Get the value of the possibly cached item into the field.
*/

void Item_cache_wrapper::save_val(Field *to)
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::val_int");
  if (!expr_cache)
  {
    orig_item->save_val(to);
    null_value= orig_item->null_value;
    DBUG_VOID_RETURN;
  }

  if ((cached_value= check_cache()))
  {
    cached_value->save_val(to);
    null_value= cached_value->null_value;
    DBUG_VOID_RETURN;
  }
  cache();
  null_value= expr_value->null_value;
  expr_value->save_val(to);
  DBUG_VOID_RETURN;
}


/**
  Get the integer value of the possibly cached item.
*/

longlong Item_cache_wrapper::val_int()
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::val_int");
  if (!expr_cache)
  {
    longlong tmp= orig_item->val_int();
    null_value= orig_item->null_value;
    DBUG_RETURN(tmp);
  }

  if ((cached_value= check_cache()))
  {
    longlong tmp= cached_value->val_int();
    null_value= cached_value->null_value;
    DBUG_RETURN(tmp);
  }
  cache();
  null_value= expr_value->null_value;
  DBUG_RETURN(expr_value->val_int());
}


/**
  Get the real value of the possibly cached item
*/

double Item_cache_wrapper::val_real()
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::val_real");
  if (!expr_cache)
  {
    double tmp= orig_item->val_real();
    null_value= orig_item->null_value;
    DBUG_RETURN(tmp);
  }

  if ((cached_value= check_cache()))
  {
    double tmp= cached_value->val_real();
    null_value= cached_value->null_value;
    DBUG_RETURN(tmp);
  }
  cache();
  null_value= expr_value->null_value;
  DBUG_RETURN(expr_value->val_real());
}


/**
  Get the string value of the possibly cached item
*/

String *Item_cache_wrapper::val_str(String* str)
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::val_str");
  if (!expr_cache)
  {
    String *tmp= orig_item->val_str(str);
    null_value= orig_item->null_value;
    DBUG_RETURN(tmp);
  }

  if ((cached_value= check_cache()))
  {
    String *tmp= cached_value->val_str(str);
    null_value= cached_value->null_value;
    DBUG_RETURN(tmp);
  }
  cache();
  if ((null_value= expr_value->null_value))
    DBUG_RETURN(NULL);
  DBUG_RETURN(expr_value->val_str(str));
}


/**
  Get the decimal value of the possibly cached item
*/

my_decimal *Item_cache_wrapper::val_decimal(my_decimal* decimal_value)
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::val_decimal");
  if (!expr_cache)
  {
    my_decimal *tmp= orig_item->val_decimal(decimal_value);
    null_value= orig_item->null_value;
    DBUG_RETURN(tmp);
  }

  if ((cached_value= check_cache()))
  {
    my_decimal *tmp= cached_value->val_decimal(decimal_value);
    null_value= cached_value->null_value;
    DBUG_RETURN(tmp);
  }
  cache();
  if ((null_value= expr_value->null_value))
    DBUG_RETURN(NULL);
  DBUG_RETURN(expr_value->val_decimal(decimal_value));
}


/**
  Get the boolean value of the possibly cached item
*/

bool Item_cache_wrapper::val_bool()
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::val_bool");
  if (!expr_cache)
  {
    bool tmp= orig_item->val_bool();
    null_value= orig_item->null_value;
    DBUG_RETURN(tmp);
  }

  if ((cached_value= check_cache()))
  {
    bool tmp= cached_value->val_bool();
    null_value= cached_value->null_value;
    DBUG_RETURN(tmp);
  }
  cache();
  null_value= expr_value->null_value;
  DBUG_RETURN(expr_value->val_bool());
}


/**
  Check for NULL the value of the possibly cached item
*/

bool Item_cache_wrapper::is_null()
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::is_null");
  if (!expr_cache)
  {
    bool tmp= orig_item->is_null();
    null_value= orig_item->null_value;
    DBUG_RETURN(tmp);
  }

  if ((cached_value= check_cache()))
  {
    bool tmp= cached_value->is_null();
    null_value= cached_value->null_value;
    DBUG_RETURN(tmp);
  }
  cache();
  DBUG_RETURN((null_value= expr_value->null_value));
}


/**
  Get the date value of the possibly cached item
*/

bool Item_cache_wrapper::get_date(MYSQL_TIME *ltime, uint fuzzydate)
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::get_date");
  if (!expr_cache)
    DBUG_RETURN((null_value= orig_item->get_date(ltime, fuzzydate)));

  if ((cached_value= check_cache()))
    DBUG_RETURN((null_value= cached_value->get_date(ltime, fuzzydate)));

  cache();
  DBUG_RETURN((null_value= expr_value->get_date(ltime, fuzzydate)));
}


/**
  Get the time value of the possibly cached item
*/

bool Item_cache_wrapper::get_time(MYSQL_TIME *ltime)
{
  Item *cached_value;
  DBUG_ENTER("Item_cache_wrapper::get_time");
  if (!expr_cache)
    DBUG_RETURN((null_value= orig_item->get_time(ltime)));

  if ((cached_value= check_cache()))
    DBUG_RETURN((null_value= cached_value->get_time(ltime)));

  cache();
  DBUG_RETURN((null_value= expr_value->get_time(ltime)));
}


int Item_cache_wrapper::save_in_field(Field *to, bool no_conversions)
{
  int res;
  DBUG_ASSERT(!result_field);
  res= orig_item->save_in_field(to, no_conversions);
  null_value= orig_item->null_value;
  return res;
}


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Item* Item_cache_wrapper::get_tmp_table_item(THD *thd_arg)
{
  if (!orig_item->with_sum_func && !orig_item->const_item())
    return new Item_field(result_field);
  return copy_or_same(thd_arg);
}


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/**
  Prepare referenced field then call usual Item_direct_ref::fix_fields .
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  @param thd         thread handler
  @param reference   reference on reference where this item stored
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  @retval
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    FALSE   OK
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  @retval
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    TRUE    Error
*/

bool Item_direct_view_ref::fix_fields(THD *thd, Item **reference)
{
  /* view fild reference must be defined */
  DBUG_ASSERT(*ref);
  /* (*ref)->check_cols() will be made in Item_direct_ref::fix_fields */
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  if ((*ref)->fixed)
  {
    Item *ref_item= (*ref)->real_item();
    if (ref_item->type() == Item::FIELD_ITEM)
    {
      /*
        In some cases we need to update table read set(see bug#47150).
        If ref item is FIELD_ITEM and fixed then field and table
        have proper values. So we can use them for update.
      */
      Field *fld= ((Item_field*) ref_item)->field;
      DBUG_ASSERT(fld && fld->table);
      if (thd->mark_used_columns == MARK_COLUMNS_READ)
        bitmap_set_bit(fld->table->read_set, fld->field_index);
    }
  }
  else if (!(*ref)->fixed &&
           ((*ref)->fix_fields(thd, ref)))
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    return TRUE;
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  return Item_direct_ref::fix_fields(thd, reference);
}

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/*
  Prepare referenced outer field then call usual Item_direct_ref::fix_fields

  SYNOPSIS
    Item_outer_ref::fix_fields()
    thd         thread handler
    reference   reference on reference where this item stored

  RETURN
    FALSE   OK
    TRUE    Error
*/

bool Item_outer_ref::fix_fields(THD *thd, Item **reference)
{
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  bool err;
  /* outer_ref->check_cols() will be made in Item_direct_ref::fix_fields */
  if ((*ref) && !(*ref)->fixed && ((*ref)->fix_fields(thd, reference)))
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    return TRUE;
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  err= Item_direct_ref::fix_fields(thd, reference);
  if (!outer_ref)
    outer_ref= *ref;
  if ((*ref)->type() == Item::FIELD_ITEM)
    table_name= ((Item_field*)outer_ref)->table_name;
  return err;
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}

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void Item_outer_ref::fix_after_pullout(st_select_lex *new_parent, Item **ref)
{
  if (depended_from == new_parent)
  {
    *ref= outer_ref;
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    (*ref)->fix_after_pullout(new_parent, ref);
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  }
}

void Item_ref::fix_after_pullout(st_select_lex *new_parent, Item **refptr)
{
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  (*ref)->fix_after_pullout(new_parent, ref);
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  if (depended_from == new_parent)
    depended_from= NULL;
}


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/**
  Mark references from inner selects used in group by clause

  The method is used by the walk method when called for the expressions
  from the group by clause. The callsare  occurred in the function
  fix_inner_refs invoked by JOIN::prepare.
  The parameter passed to Item_outer_ref::check_inner_refs_processor
  is the iterator over the list of inner references from the subselects
  of the select to be prepared. The function marks those references
  from this list whose occurrences are encountered in the group by 
  expressions passed to the walk method.  
 
  @param arg  pointer to the iterator over a list of inner references

  @return
    FALSE always
*/

bool Item_outer_ref::check_inner_refs_processor(uchar *arg)
{
  List_iterator_fast<Item_outer_ref> *it=
    ((List_iterator_fast<Item_outer_ref> *) arg);
  Item_outer_ref *ref;
  while ((ref= (*it)++))
  {
    if (ref == this)
    {
      ref->found_in_group_by= 1;
      break;
    }
  }
  (*it).rewind();
  return FALSE;
}


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/**
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  Compare two view column references for equality.
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  A view column reference is considered equal to another column
  reference if the second one is a view column and if both column
  references resolve to the same item. It is assumed that both
  items are of the same type.
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  @param item        item to compare with
  @param binary_cmp  make binary comparison
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  @retval
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    TRUE    Referenced item is equal to given item
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  @retval
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    FALSE   otherwise
*/

bool Item_direct_view_ref::eq(const Item *item, bool binary_cmp) const
{
7282 7283 7284 7285 7286 7287
  if (item->type() == REF_ITEM)
  {
    Item_ref *item_ref= (Item_ref*) item;
    if (item_ref->ref_type() == VIEW_REF)
    {
      Item *item_ref_ref= *(item_ref->ref);
7288
      return ((*ref)->real_item() == item_ref_ref->real_item());
7289 7290 7291
    }
  }
  return FALSE;
7292
}
7293

7294 7295 7296 7297 7298 7299 7300 7301 7302 7303 7304 7305 7306 7307 7308 7309 7310 7311 7312 7313 7314 7315 7316 7317 7318 7319 7320 7321 7322 7323 7324 7325 7326 7327 7328 7329 7330 7331 7332 7333 7334 7335 7336 7337 7338 7339 7340 7341 7342 7343 7344 7345 7346 7347 7348 7349 7350 7351 7352 7353 7354 7355 7356 7357 7358 7359 7360 7361 7362 7363 7364 7365 7366 7367 7368 7369 7370 7371 7372 7373 7374 7375 7376 7377 7378 7379 7380 7381 7382 7383 7384 7385 7386 7387 7388 7389 7390 7391 7392 7393 7394 7395 7396 7397 7398 7399 7400 7401 7402 7403 7404 7405 7406 7407 7408 7409 7410 7411 7412 7413 7414 7415 7416 7417

Item_equal *Item_direct_view_ref::find_item_equal(COND_EQUAL *cond_equal)
{
  Item* field_item= real_item();
  if (field_item->type() != FIELD_ITEM)
    return NULL;
  return ((Item_field *) field_item)->find_item_equal(cond_equal);  
}


/**
  Check whether a reference to field item can be substituted for an equal item

  @details
  The function checks whether a substitution of a reference to field item for
  an equal item is valid.

  @param arg   *arg != NULL && **arg <-> the reference is in the context
               where substitution for an equal item is valid

  @note
    See also the note for Item_field::subst_argument_checker

  @retval
    TRUE   substitution is valid
  @retval
    FALSE  otherwise
*/
bool Item_direct_view_ref::subst_argument_checker(uchar **arg)
{
  bool res=  (!(*arg) && (result_type() != STRING_RESULT)) ||
          ((*arg) && (**arg));
  /* Block any substitution into the wrapped object */
  if (*arg)
    **arg= (uchar) 0;
  return res; 
}


/**
  Set a pointer to the multiple equality the view field reference belongs to
  (if any).

  @details
  The function looks for a multiple equality containing this item of the type
  Item_direct_view_ref among those referenced by arg.
  In the case such equality exists the function does the following.
  If the found multiple equality contains a constant, then the item
  is substituted for this constant, otherwise the function sets a pointer
  to the multiple equality in the item.

  @param arg    reference to list of multiple equalities where
                the item (this object) is to be looked for

  @note
    This function is supposed to be called as a callback parameter in calls
    of the compile method.

  @note 
    The function calls Item_field::equal_fields_propagator for the field item
    this->real_item() to do the job. Then it takes the pointer to equal_item
    from this field item and assigns it to this->item_equal.

  @return
    - pointer to the replacing constant item, if the field item was substituted
    - pointer to the field item, otherwise.
*/

Item *Item_direct_view_ref::equal_fields_propagator(uchar *arg)
{
  Item *field_item= real_item();
  if (field_item->type() != FIELD_ITEM)
    return this;
  Item *item= field_item->equal_fields_propagator(arg);
  set_item_equal(field_item->get_item_equal());
  field_item->set_item_equal(NULL);
  if (item != field_item)
    return item;
  return this;
}


/**
  Replace an Item_direct_view_ref for an equal Item_field evaluated earlier
  (if any).

  @details
  If this->item_equal points to some item and coincides with arg then
  the function returns a pointer to a field item that is referred to by the 
  first element of the item_equal list which the Item_direct_view_ref
  object belongs to unless item_equal contains  a constant item. In this
  case the function returns this constant item (if the substitution does
   not require conversion).   
  If the Item_direct_view_item object does not refer any Item_equal object
  'this' is returned .

  @param arg   NULL or points to so some item of the Item_equal type  

  @note
    This function is supposed to be called as a callback parameter in calls
    of the transformer method.

  @note 
    The function calls Item_field::replace_equal_field for the field item
    this->real_item() to do the job.

  @return
    - pointer to a replacement Item_field if there is a better equal item or
      a pointer to a constant equal item;
    - this - otherwise.
*/

Item *Item_direct_view_ref::replace_equal_field(uchar *arg)
{
  Item *field_item= real_item();
  if (field_item->type() != FIELD_ITEM)
    return this;
  field_item->set_item_equal(item_equal);
  Item *item= field_item->replace_equal_field(arg);
  field_item->set_item_equal(0);
  return item;
}


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bool Item_default_value::eq(const Item *item, bool binary_cmp) const
{
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  return item->type() == DEFAULT_VALUE_ITEM && 
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    ((Item_default_value *)item)->arg->eq(arg, binary_cmp);
}

7424

7425
bool Item_default_value::fix_fields(THD *thd, Item **items)
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{
7427
  Item *real_arg;
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  Item_field *field_arg;
  Field *def_field;
7430
  DBUG_ASSERT(fixed == 0);
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  if (!arg)
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  {
    fixed= 1;
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    return FALSE;
7436
  }
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  if (!arg->fixed && arg->fix_fields(thd, &arg))
    goto error;

7440

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  real_arg= arg->real_item();
  if (real_arg->type() != FIELD_ITEM)
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  {
7444
    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), arg->name);
7445
    goto error;
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  }
7447

7448
  field_arg= (Item_field *)real_arg;
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  if (field_arg->field->flags & NO_DEFAULT_VALUE_FLAG)
  {
7451
    my_error(ER_NO_DEFAULT_FOR_FIELD, MYF(0), field_arg->field->field_name);
7452
    goto error;
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  }
  if (!(def_field= (Field*) sql_alloc(field_arg->field->size_of())))
7455
    goto error;
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  memcpy(def_field, field_arg->field, field_arg->field->size_of());
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  def_field->move_field_offset((my_ptrdiff_t)
                               (def_field->table->s->default_values -
                                def_field->table->record[0]));
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  set_field(def_field);
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  return FALSE;
7462 7463 7464 7465

error:
  context->process_error(thd);
  return TRUE;
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}

7468

7469
void Item_default_value::print(String *str, enum_query_type query_type)
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{
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  if (!arg)
  {
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    str->append(STRING_WITH_LEN("default"));
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    return;
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  }
7476
  str->append(STRING_WITH_LEN("default("));
7477
  arg->print(str, query_type);
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  str->append(')');
}
7480

7481 7482 7483 7484 7485

int Item_default_value::save_in_field(Field *field_arg, bool no_conversions)
{
  if (!arg)
  {
7486 7487
    if (field_arg->flags & NO_DEFAULT_VALUE_FLAG &&
        field_arg->real_type() != MYSQL_TYPE_ENUM)
7488
    {
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      if (field_arg->reset())
      {
        my_message(ER_CANT_CREATE_GEOMETRY_OBJECT,
                   ER(ER_CANT_CREATE_GEOMETRY_OBJECT), MYF(0));
        return -1;
      }

7496 7497
      if (context->error_processor == &view_error_processor)
      {
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        TABLE_LIST *view= cached_table->top_table();
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        push_warning_printf(field_arg->table->in_use,
                            MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_NO_DEFAULT_FOR_VIEW_FIELD,
                            ER(ER_NO_DEFAULT_FOR_VIEW_FIELD),
                            view->view_db.str,
                            view->view_name.str);
      }
      else
      {
        push_warning_printf(field_arg->table->in_use,
                            MYSQL_ERROR::WARN_LEVEL_WARN,
                            ER_NO_DEFAULT_FOR_FIELD,
                            ER(ER_NO_DEFAULT_FOR_FIELD),
                            field_arg->field_name);
      }
7514 7515 7516 7517 7518 7519 7520 7521 7522
      return 1;
    }
    field_arg->set_default();
    return 0;
  }
  return Item_field::save_in_field(field_arg, no_conversions);
}


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/**
7524
  This method like the walk method traverses the item tree, but at the
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  same time it can replace some nodes in the tree.
7526
*/ 
7527

7528
Item *Item_default_value::transform(Item_transformer transformer, uchar *args)
7529 7530 7531
{
  DBUG_ASSERT(!current_thd->is_stmt_prepare());

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  /*
    If the value of arg is NULL, then this object represents a constant,
    so further transformation is unnecessary (and impossible).
  */
  if (!arg)
    return 0;

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  Item *new_item= arg->transform(transformer, args);
  if (!new_item)
    return 0;

  /*
    THD::change_item_tree() should be called only if the tree was
    really transformed, i.e. when a new item has been created.
    Otherwise we'll be allocating a lot of unnecessary memory for
    change records at each execution.
  */
  if (arg != new_item)
    current_thd->change_item_tree(&arg, new_item);
  return (this->*transformer)(args);
}


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bool Item_insert_value::eq(const Item *item, bool binary_cmp) const
{
  return item->type() == INSERT_VALUE_ITEM &&
    ((Item_default_value *)item)->arg->eq(arg, binary_cmp);
}


7562
bool Item_insert_value::fix_fields(THD *thd, Item **items)
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{
7564
  DBUG_ASSERT(fixed == 0);
7565
  /* We should only check that arg is in first table */
7566
  if (!arg->fixed)
7567
  {
7568
    bool res;
7569
    TABLE_LIST *orig_next_table= context->last_name_resolution_table;
7570 7571
    context->last_name_resolution_table= context->first_name_resolution_table;
    res= arg->fix_fields(thd, &arg);
7572
    context->last_name_resolution_table= orig_next_table;
7573 7574
    if (res)
      return TRUE;
7575
  }
7576

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  if (arg->type() == REF_ITEM)
  {
    Item_ref *ref= (Item_ref *)arg;
    if (ref->ref[0]->type() != FIELD_ITEM)
    {
7582
      my_error(ER_BAD_FIELD_ERROR, MYF(0), "", "VALUES() function");
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      return TRUE;
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    }
    arg= ref->ref[0];
  }
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  /*
    According to our SQL grammar, VALUES() function can reference
    only to a column.
  */
  DBUG_ASSERT(arg->type() == FIELD_ITEM);

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  Item_field *field_arg= (Item_field *)arg;
7594

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  if (field_arg->field->table->insert_values)
  {
    Field *def_field= (Field*) sql_alloc(field_arg->field->size_of());
    if (!def_field)
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      return TRUE;
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    memcpy(def_field, field_arg->field, field_arg->field->size_of());
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    def_field->move_field_offset((my_ptrdiff_t)
                                 (def_field->table->insert_values -
                                  def_field->table->record[0]));
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    set_field(def_field);
  }
  else
  {
7608
    Field *tmp_field= field_arg->field;
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    /* charset doesn't matter here, it's to avoid sigsegv only */
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    tmp_field= new Field_null(0, 0, Field::NONE, field_arg->field->field_name,
                          &my_charset_bin);
    if (tmp_field)
    {
      tmp_field->init(field_arg->field->table);
      set_field(tmp_field);
    }
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  }
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  return FALSE;
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}

7621
void Item_insert_value::print(String *str, enum_query_type query_type)
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{
7623
  str->append(STRING_WITH_LEN("values("));
7624
  arg->print(str, query_type);
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  str->append(')');
}

7628

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/**
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  Find index of Field object which will be appropriate for item
  representing field of row being changed in trigger.
7632

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  @param thd     current thread context
  @param table   table of trigger (and where we looking for fields)
  @param table_grant_info   GRANT_INFO of the subject table
7636

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  @note
7638
    This function does almost the same as fix_fields() for Item_field
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    but is invoked right after trigger definition parsing. Since at
    this stage we can't say exactly what Field object (corresponding
    to TABLE::record[0] or TABLE::record[1]) should be bound to this
    Item, we only find out index of the Field and then select concrete
    Field object in fix_fields() (by that time Table_trigger_list::old_field/
    new_field should point to proper array of Fields).
    It also binds Item_trigger_field to Table_triggers_list object for
    table of trigger which uses this item.
7647
*/
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7648

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void Item_trigger_field::setup_field(THD *thd, TABLE *table,
                                     GRANT_INFO *table_grant_info)
7651
{
7652
  /*
7653 7654 7655 7656 7657
    It is too early to mark fields used here, because before execution
    of statement that will invoke trigger other statements may use same
    TABLE object, so all such mark-up will be wiped out.
    So instead we do it in Table_triggers_list::mark_fields_used()
    method which is called during execution of these statements.
7658
  */
7659 7660
  enum_mark_columns save_mark_used_columns= thd->mark_used_columns;
  thd->mark_used_columns= MARK_COLUMNS_NONE;
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  /*
    Try to find field by its name and if it will be found
    set field_idx properly.
  */
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  (void)find_field_in_table(thd, table, field_name, (uint) strlen(field_name),
7666
                            0, &field_idx);
7667
  thd->mark_used_columns= save_mark_used_columns;
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  triggers= table->triggers;
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  table_grants= table_grant_info;
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}


bool Item_trigger_field::eq(const Item *item, bool binary_cmp) const
{
  return item->type() == TRIGGER_FIELD_ITEM &&
         row_version == ((Item_trigger_field *)item)->row_version &&
         !my_strcasecmp(system_charset_info, field_name,
                        ((Item_trigger_field *)item)->field_name);
}


7682
void Item_trigger_field::set_required_privilege(bool rw)
7683 7684 7685 7686 7687 7688 7689 7690 7691
{
  /*
    Require SELECT and UPDATE privilege if this field will be read and
    set, and only UPDATE privilege for setting the field.
  */
  want_privilege= (rw ? SELECT_ACL | UPDATE_ACL : UPDATE_ACL);
}


7692
bool Item_trigger_field::set_value(THD *thd, sp_rcontext * /*ctx*/, Item **it)
7693
{
7694
  Item *item= sp_prepare_func_item(thd, it);
7695 7696 7697 7698 7699 7700

  return (!item || (!fixed && fix_fields(thd, 0)) ||
          (item->save_in_field(field, 0) < 0));
}


7701
bool Item_trigger_field::fix_fields(THD *thd, Item **items)
7702 7703 7704 7705 7706 7707
{
  /*
    Since trigger is object tightly associated with TABLE object most
    of its set up can be performed during trigger loading i.e. trigger
    parsing! So we have little to do in fix_fields. :)
  */
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7709
  DBUG_ASSERT(fixed == 0);
7710

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  /* Set field. */

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  if (field_idx != (uint)-1)
7714
  {
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#ifndef NO_EMBEDDED_ACCESS_CHECKS
    /*
      Check access privileges for the subject table. We check privileges only
      in runtime.
    */

    if (table_grants)
    {
7723
      table_grants->want_privilege= want_privilege;
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      if (check_grant_column(thd, table_grants, triggers->trigger_table->s->db.str,
                             triggers->trigger_table->s->table_name.str, field_name,
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                             strlen(field_name), thd->security_ctx))
        return TRUE;
    }
#endif // NO_EMBEDDED_ACCESS_CHECKS

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    field= (row_version == OLD_ROW) ? triggers->old_field[field_idx] :
                                      triggers->new_field[field_idx];
7734 7735
    set_field(field);
    fixed= 1;
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    return FALSE;
7737 7738 7739 7740
  }

  my_error(ER_BAD_FIELD_ERROR, MYF(0), field_name,
           (row_version == NEW_ROW) ? "NEW" : "OLD");
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  return TRUE;
7742 7743 7744
}


7745
void Item_trigger_field::print(String *str, enum_query_type query_type)
7746 7747 7748 7749 7750 7751 7752 7753 7754
{
  str->append((row_version == NEW_ROW) ? "NEW" : "OLD", 3);
  str->append('.');
  str->append(field_name);
}


void Item_trigger_field::cleanup()
{
7755
  want_privilege= original_privilege;
7756 7757 7758 7759 7760 7761 7762 7763
  /*
    Since special nature of Item_trigger_field we should not do most of
    things from Item_field::cleanup() or Item_ident::cleanup() here.
  */
  Item::cleanup();
}


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Item_result item_cmp_type(Item_result a,Item_result b)
{
  if (a == STRING_RESULT && b == STRING_RESULT)
    return STRING_RESULT;
7768
  if (a == INT_RESULT && b == INT_RESULT)
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    return INT_RESULT;
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  else if (a == ROW_RESULT || b == ROW_RESULT)
    return ROW_RESULT;
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  if ((a == INT_RESULT || a == DECIMAL_RESULT) &&
      (b == INT_RESULT || b == DECIMAL_RESULT))
    return DECIMAL_RESULT;
7775
  return REAL_RESULT;
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}


7779
void resolve_const_item(THD *thd, Item **ref, Item *comp_item)
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{
7781
  Item *item= *ref;
7782
  Item *new_item= NULL;
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  if (item->basic_const_item())
7784
    return;                                     // Can't be better
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  Item_result res_type=item_cmp_type(comp_item->result_type(),
				     item->result_type());
  char *name=item->name;			// Alloced by sql_alloc

7789
  switch (res_type) {
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  case STRING_RESULT:
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  {
    char buff[MAX_FIELD_WIDTH];
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    String tmp(buff,sizeof(buff),&my_charset_bin),*result;
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    result=item->val_str(&tmp);
    if (item->null_value)
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      new_item= new Item_null(name);
    else
    {
      uint length= result->length();
      char *tmp_str= sql_strmake(result->ptr(), length);
      new_item= new Item_string(name, tmp_str, length, result->charset());
    }
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    break;
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  }
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  case INT_RESULT:
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  {
    longlong result=item->val_int();
    uint length=item->max_length;
    bool null_value=item->null_value;
7810 7811
    new_item= (null_value ? (Item*) new Item_null(name) :
               (Item*) new Item_int(name, result, length));
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    break;
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  }
7814
  case ROW_RESULT:
7815
  if (item->type() == Item::ROW_ITEM && comp_item->type() == Item::ROW_ITEM)
7816
  {
7817 7818 7819 7820 7821 7822 7823 7824
    /*
      Substitute constants only in Item_rows. Don't affect other Items
      with ROW_RESULT (eg Item_singlerow_subselect).

      For such Items more optimal is to detect if it is constant and replace
      it with Item_row. This would optimize queries like this:
      SELECT * FROM t1 WHERE (a,b) = (SELECT a,b FROM t2 LIMIT 1);
    */
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    Item_row *item_row= (Item_row*) item;
    Item_row *comp_item_row= (Item_row*) comp_item;
    uint col;
7828 7829 7830
    new_item= 0;
    /*
      If item and comp_item are both Item_rows and have same number of cols
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      then process items in Item_row one by one.
      We can't ignore NULL values here as this item may be used with <=>, in
      which case NULL's are significant.
7834
    */
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    DBUG_ASSERT(item->result_type() == comp_item->result_type());
    DBUG_ASSERT(item_row->cols() == comp_item_row->cols());
    col= item_row->cols();
    while (col-- > 0)
7839 7840
      resolve_const_item(thd, item_row->addr(col),
                         comp_item_row->element_index(col));
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    break;
7842
  }
7843
  /* Fallthrough */
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  case REAL_RESULT:
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  {						// It must REAL_RESULT
7846
    double result= item->val_real();
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    uint length=item->max_length,decimals=item->decimals;
    bool null_value=item->null_value;
7849
    new_item= (null_value ? (Item*) new Item_null(name) : (Item*)
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               new Item_float(name, result, decimals, length));
    break;
  }
  case DECIMAL_RESULT:
  {
    my_decimal decimal_value;
    my_decimal *result= item->val_decimal(&decimal_value);
    uint length= item->max_length, decimals= item->decimals;
    bool null_value= item->null_value;
    new_item= (null_value ?
               (Item*) new Item_null(name) :
               (Item*) new Item_decimal(name, result, length, decimals));
    break;
  }
  default:
    DBUG_ASSERT(0);
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  }
7867 7868
  if (new_item)
    thd->change_item_tree(ref, new_item);
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}

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/**
7872
  Compare the value stored in field with the expression from the query.
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7873

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  @param field   Field which the Item is stored in after conversion
  @param item    Original expression from query
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7877 7878 7879 7880
  @return Returns an integer greater than, equal to, or less than 0 if
          the value stored in the field is greater than, equal to,
          or less than the original Item. A 0 may also be returned if 
          out of memory.          
7881 7882 7883 7884

  @note We only use this on the range optimizer/partition pruning,
        because in some cases we can't store the value in the field
        without some precision/character loss.
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*/

7887
int stored_field_cmp_to_item(THD *thd, Field *field, Item *item)
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{
  Item_result res_type=item_cmp_type(field->result_type(),
				     item->result_type());
  if (res_type == STRING_RESULT)
  {
    char item_buff[MAX_FIELD_WIDTH];
    char field_buff[MAX_FIELD_WIDTH];
7895 7896
    
    String item_tmp(item_buff,sizeof(item_buff),&my_charset_bin);
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    String field_tmp(field_buff,sizeof(field_buff),&my_charset_bin);
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    String *item_result= item->val_str(&item_tmp);
    /*
      Some implementations of Item::val_str(String*) actually modify
      the field Item::null_value, hence we can't check it earlier.
    */
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7903
    if (item->null_value)
7904
      return 0;
7905
    String *field_result= field->val_str(&field_tmp);
7906

7907 7908
    enum_field_types field_type= field->type();

7909 7910
    if (field_type == MYSQL_TYPE_DATE || field_type == MYSQL_TYPE_DATETIME ||
        field_type == MYSQL_TYPE_TIMESTAMP)
7911
    {
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      enum_mysql_timestamp_type type= MYSQL_TIMESTAMP_ERROR;

      if (field_type == MYSQL_TYPE_DATE)
        type= MYSQL_TIMESTAMP_DATE;
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7916
      else
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        type= MYSQL_TIMESTAMP_DATETIME;
        
      const char *field_name= field->field_name;
      MYSQL_TIME field_time, item_time;
      get_mysql_time_from_str(thd, field_result, type, field_name, &field_time);
      get_mysql_time_from_str(thd, item_result, type, field_name,  &item_time);
7923

7924
      return my_time_compare(&field_time, &item_time);
7925
    }
7926
    return stringcmp(field_result, item_result);
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  }
  if (res_type == INT_RESULT)
7929
    return 0;					// Both are of type int
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  if (res_type == DECIMAL_RESULT)
  {
    my_decimal item_buf, *item_val,
               field_buf, *field_val;
    item_val= item->val_decimal(&item_buf);
    if (item->null_value)
7936
      return 0;
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    field_val= field->val_decimal(&field_buf);
7938
    return my_decimal_cmp(item_val, field_val);
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  }
7940
  double result= item->val_real();
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  if (item->null_value)
7942 7943 7944 7945 7946
    return 0;
  double field_result= field->val_real();
  if (field_result < result)
    return -1;
  else if (field_result > result)
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    return 1;
7948
  return 0;
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}

7951
Item_cache* Item_cache::get_cache(const Item *item)
7952
{
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  return get_cache(item, item->result_type());
}


/**
  Get a cache item of given type.

  @param item         value to be cached
  @param type         required type of cache

  @return cache item
*/

Item_cache* Item_cache::get_cache(const Item *item, const Item_result type)
{
  switch (type) {
7969
  case INT_RESULT:
7970
    return new Item_cache_int(item->field_type());
7971 7972
  case REAL_RESULT:
    return new Item_cache_real();
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  case DECIMAL_RESULT:
    return new Item_cache_decimal();
7975
  case STRING_RESULT:
7976
    return new Item_cache_str(item);
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  case ROW_RESULT:
    return new Item_cache_row();
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  default:
    // should never be in real life
    DBUG_ASSERT(0);
    return 0;
  }
}

7986 7987
void Item_cache::store(Item *item)
{
7988 7989 7990
  example= item;
  if (!item)
    null_value= TRUE;
7991 7992
  value_cached= FALSE;
}
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7993

7994
void Item_cache::print(String *str, enum_query_type query_type)
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{
7996
  str->append(STRING_WITH_LEN("<cache>("));
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  if (example)
7998
    example->print(str, query_type);
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  else
8000
    Item::print(str, query_type);
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  str->append(')');
}

8004
bool  Item_cache_int::cache_value()
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{
8006 8007
  if (!example)
    return FALSE;
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  value_cached= TRUE;
  value= example->val_int_result();
  null_value= example->null_value;
  unsigned_flag= example->unsigned_flag;
8012
  return TRUE;
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}


8016
void Item_cache_int::store_longlong(Item *item, longlong val_arg)
8017
{
8018 8019
  /* An explicit values is given, save it. */
  value_cached= TRUE;
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  value= val_arg;
  null_value= item->null_value;
  unsigned_flag= item->unsigned_flag;
}


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String *Item_cache_int::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
8029 8030 8031
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8032
    return NULL;
8033
  }
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  str->set(value, default_charset());
  return str;
}


my_decimal *Item_cache_int::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
8042 8043 8044
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8045
    return NULL;
8046
  }
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  int2my_decimal(E_DEC_FATAL_ERROR, value, unsigned_flag, decimal_val);
  return decimal_val;
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}

8051 8052 8053
double Item_cache_int::val_real()
{
  DBUG_ASSERT(fixed == 1);
8054 8055 8056
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8057
    return 0.0;
8058
  }
8059 8060
  return (double) value;
}
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8061

8062
longlong Item_cache_int::val_int()
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{
8064
  DBUG_ASSERT(fixed == 1);
8065 8066 8067
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8068
    return 0;
8069
  }
8070
  return value;
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}

8073
bool Item_cache_real::cache_value()
8074
{
8075 8076
  if (!example)
    return FALSE;
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  value_cached= TRUE;
  value= example->val_result();
  null_value= example->null_value;
8080
  return TRUE;
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}


8084 8085 8086
double Item_cache_real::val_real()
{
  DBUG_ASSERT(fixed == 1);
8087 8088 8089
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8090
    return 0.0;
8091
  }
8092 8093
  return value;
}
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longlong Item_cache_real::val_int()
{
  DBUG_ASSERT(fixed == 1);
8098 8099 8100
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8101
    return 0;
8102
  }
8103
  return (longlong) rint(value);
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}


String* Item_cache_real::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
8110 8111 8112
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8113
    return NULL;
8114
  }
8115
  str->set_real(value, decimals, default_charset());
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  return str;
}


my_decimal *Item_cache_real::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
8123 8124 8125
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8126
    return NULL;
8127
  }
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  double2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
  return decimal_val;
}


8133
bool Item_cache_decimal::cache_value()
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{
8135 8136
  if (!example)
    return FALSE;
8137 8138 8139
  value_cached= TRUE;
  my_decimal *val= example->val_decimal_result(&decimal_value);
  if (!(null_value= example->null_value) && val != &decimal_value)
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    my_decimal2decimal(val, &decimal_value);
8141
  return TRUE;
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}

double Item_cache_decimal::val_real()
{
  DBUG_ASSERT(fixed);
  double res;
8148 8149 8150
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8151
    return 0.0;
8152
  }
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  my_decimal2double(E_DEC_FATAL_ERROR, &decimal_value, &res);
  return res;
}

longlong Item_cache_decimal::val_int()
{
  DBUG_ASSERT(fixed);
  longlong res;
8161 8162 8163
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8164
    return 0;
8165
  }
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  my_decimal2int(E_DEC_FATAL_ERROR, &decimal_value, unsigned_flag, &res);
  return res;
}

String* Item_cache_decimal::val_str(String *str)
{
  DBUG_ASSERT(fixed);
8173 8174 8175
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8176
    return NULL;
8177
  }
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  my_decimal_round(E_DEC_FATAL_ERROR, &decimal_value, decimals, FALSE,
                   &decimal_value);
  my_decimal2string(E_DEC_FATAL_ERROR, &decimal_value, 0, 0, 0, str);
  return str;
}

my_decimal *Item_cache_decimal::val_decimal(my_decimal *val)
{
  DBUG_ASSERT(fixed);
8187 8188 8189
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8190
    return NULL;
8191
  }
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  return &decimal_value;
}


8196
bool Item_cache_str::cache_value()
8197
{
8198 8199
  if (!example)
    return FALSE;
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  value_cached= TRUE;
  value_buff.set(buffer, sizeof(buffer), example->collation.collation);
  value= example->str_result(&value_buff);
  if ((null_value= example->null_value))
8204
    value= 0;
8205
  else if (value != &value_buff)
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  {
    /*
      We copy string value to avoid changing value if 'item' is table field
      in queries like following (where t1.c is varchar):
      select a, 
             (select a,b,c from t1 where t1.a=t2.a) = ROW(a,2,'a'),
             (select c from t1 where a=t2.a)
        from t2;
    */
8215 8216
    value_buff.copy(*value);
    value= &value_buff;
8217
  }
8218
  return TRUE;
8219
}
8220

8221
double Item_cache_str::val_real()
8222 8223
{
  DBUG_ASSERT(fixed == 1);
8224 8225
  int err_not_used;
  char *end_not_used;
8226 8227 8228
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8229
    return 0.0;
8230 8231 8232
  }
  return my_strntod(value->charset(), (char*) value->ptr(),
                    value->length(), &end_not_used, &err_not_used);
8233
}
8234 8235


8236 8237
longlong Item_cache_str::val_int()
{
8238
  DBUG_ASSERT(fixed == 1);
8239
  int err;
8240 8241 8242
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8243
    return 0;
8244 8245 8246
  }
  return my_strntoll(value->charset(), value->ptr(),
                     value->length(), 10, (char**) 0, &err);
8247
}
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8249 8250 8251 8252

String* Item_cache_str::val_str(String *str)
{
  DBUG_ASSERT(fixed == 1);
8253 8254 8255
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8256
    return 0;
8257
  }
8258 8259 8260 8261
  return value;
}


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my_decimal *Item_cache_str::val_decimal(my_decimal *decimal_val)
{
  DBUG_ASSERT(fixed == 1);
8265 8266 8267
  if ((!value_cached && !cache_value()) || null_value)
  {
    null_value= TRUE;
8268
    return NULL;
8269 8270
  }
  string2my_decimal(E_DEC_FATAL_ERROR, value, decimal_val);
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  return decimal_val;
}

8274

8275 8276
int Item_cache_str::save_in_field(Field *field, bool no_conversions)
{
8277 8278 8279 8280
  if ((!value_cached && !cache_value()) || null_value)
  {
    field->set_notnull();
    null_value= TRUE;
8281
    return 0;
8282
  }
8283 8284 8285 8286 8287 8288
  int res= Item_cache::save_in_field(field, no_conversions);
  return (is_varbinary && field->type() == MYSQL_TYPE_STRING &&
          value->length() < field->field_length) ? 1 : res;
}


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bool Item_cache_row::allocate(uint num)
{
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  item_count= num;
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  THD *thd= current_thd;
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  return (!(values= 
	    (Item_cache **) thd->calloc(sizeof(Item_cache *)*item_count)));
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}

8297

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bool Item_cache_row::setup(Item * item)
{
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  example= item;
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  if (!values && allocate(item->cols()))
    return 1;
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  for (uint i= 0; i < item_count; i++)
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  {
8305
    Item *el= item->element_index(i);
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    Item_cache *tmp;
8307
    if (!(tmp= values[i]= Item_cache::get_cache(el)))
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      return 1;
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    tmp->setup(el);
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  }
  return 0;
}

8314

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void Item_cache_row::store(Item * item)
{
8317 8318 8319 8320 8321 8322
  example= item;
  if (!item)
  {
    null_value= TRUE;
    return;
  }
8323 8324 8325 8326 8327
  for (uint i= 0; i < item_count; i++)
    values[i]->store(item->element_index(i));
}


8328
bool Item_cache_row::cache_value()
8329
{
8330 8331
  if (!example)
    return FALSE;
8332
  value_cached= TRUE;
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  null_value= 0;
8334
  example->bring_value();
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  for (uint i= 0; i < item_count; i++)
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  {
8337
    values[i]->cache_value();
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    null_value|= values[i]->null_value;
  }
8340
  return TRUE;
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}

8343

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void Item_cache_row::illegal_method_call(const char *method)
{
  DBUG_ENTER("Item_cache_row::illegal_method_call");
  DBUG_PRINT("error", ("!!! %s method was called for row item", method));
  DBUG_ASSERT(0);
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  my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
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  DBUG_VOID_RETURN;
}

8353

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bool Item_cache_row::check_cols(uint c)
{
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  if (c != item_count)
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  {
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    my_error(ER_OPERAND_COLUMNS, MYF(0), c);
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    return 1;
  }
  return 0;
}

8364

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bool Item_cache_row::null_inside()
{
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  for (uint i= 0; i < item_count; i++)
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  {
    if (values[i]->cols() > 1)
    {
      if (values[i]->null_inside())
	return 1;
    }
    else
    {
8376
      values[i]->update_null_value();
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      if (values[i]->null_value)
	return 1;
    }
  }
  return 0;
}

8384

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void Item_cache_row::bring_value()
{
8387 8388 8389 8390
  if (!example)
    return;
  example->bring_value();
  null_value= example->null_value;
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  for (uint i= 0; i < item_count; i++)
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    values[i]->bring_value();
}
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8394

8395

8396 8397
Item_type_holder::Item_type_holder(THD *thd, Item *item)
  :Item(thd, item), enum_set_typelib(0), fld_type(get_real_type(item))
8398 8399
{
  DBUG_ASSERT(item->fixed);
8400
  maybe_null= item->maybe_null;
8401
  collation.set(item->collation);
8402
  get_full_info(item);
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  /* fix variable decimals which always is NOT_FIXED_DEC */
  if (Field::result_merge_type(fld_type) == INT_RESULT)
    decimals= 0;
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  prev_decimal_int_part= item->decimal_int_part();
8407
#ifdef HAVE_SPATIAL
8408
  if (item->field_type() == MYSQL_TYPE_GEOMETRY)
8409
    geometry_type= item->get_geometry_type();
8410
#endif /* HAVE_SPATIAL */
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}


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/**
  Return expression type of Item_type_holder.
8416

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  @return
    Item_result (type of internal MySQL expression result)
8419 8420
*/

8421
Item_result Item_type_holder::result_type() const
8422
{
8423
  return Field::result_merge_type(fld_type);
8424
}
8425

8426

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/**
  Find real field type of item.
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  @return
8431
    type of field which should be created to store item value
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*/

8434
enum_field_types Item_type_holder::get_real_type(Item *item)
8435
{
8436
  switch(item->type())
8437
  {
8438
  case FIELD_ITEM:
8439
  {
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    /*
8441 8442
      Item_fields::field_type ask Field_type() but sometimes field return
      a different type, like for enum/set, so we need to ask real type.
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    */
8444 8445
    Field *field= ((Item_field *) item)->field;
    enum_field_types type= field->real_type();
8446 8447
    if (field->is_created_from_null_item)
      return MYSQL_TYPE_NULL;
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    /* work around about varchar type field detection */
    if (type == MYSQL_TYPE_STRING && field->type() == MYSQL_TYPE_VAR_STRING)
      return MYSQL_TYPE_VAR_STRING;
    return type;
8452
  }
8453
  case SUM_FUNC_ITEM:
8454
  {
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    /*
      Argument of aggregate function sometimes should be asked about field
      type
    */
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    Item_sum *item_sum= (Item_sum *) item;
    if (item_sum->keep_field_type())
8461
      return get_real_type(item_sum->get_arg(0));
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    break;
  }
  case FUNC_ITEM:
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    if (((Item_func *) item)->functype() == Item_func::GUSERVAR_FUNC)
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    {
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      /*
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        There are work around of problem with changing variable type on the
        fly and variable always report "string" as field type to get
        acceptable information for client in send_field, so we make field
        type from expression type.
8472
      */
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      switch (item->result_type()) {
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      case STRING_RESULT:
        return MYSQL_TYPE_VAR_STRING;
      case INT_RESULT:
        return MYSQL_TYPE_LONGLONG;
      case REAL_RESULT:
        return MYSQL_TYPE_DOUBLE;
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      case DECIMAL_RESULT:
        return MYSQL_TYPE_NEWDECIMAL;
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      case ROW_RESULT:
      default:
        DBUG_ASSERT(0);
        return MYSQL_TYPE_VAR_STRING;
      }
8487
    }
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    break;
  default:
    break;
8491
  }
8492
  return item->field_type();
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}

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/**
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  Find field type which can carry current Item_type_holder type and
  type of given Item.
8498

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  @param thd     thread handler
  @param item    given item to join its parameters with this item ones
8501

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  @retval
8503
    TRUE   error - types are incompatible
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  @retval
8505
    FALSE  OK
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*/

8508
bool Item_type_holder::join_types(THD *thd, Item *item)
8509
{
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  uint max_length_orig= max_length;
  uint decimals_orig= decimals;
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  DBUG_ENTER("Item_type_holder::join_types");
  DBUG_PRINT("info:", ("was type %d len %d, dec %d name %s",
                       fld_type, max_length, decimals,
                       (name ? name : "<NULL>")));
  DBUG_PRINT("info:", ("in type %d len %d, dec %d",
                       get_real_type(item),
                       item->max_length, item->decimals));
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  fld_type= Field::field_type_merge(fld_type, get_real_type(item));
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  {
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    int item_decimals= item->decimals;
    /* fix variable decimals which always is NOT_FIXED_DEC */
    if (Field::result_merge_type(fld_type) == INT_RESULT)
      item_decimals= 0;
    decimals= max(decimals, item_decimals);
8526
  }
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  if (Field::result_merge_type(fld_type) == DECIMAL_RESULT)
8528
  {
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    decimals= min(max(decimals, item->decimals), DECIMAL_MAX_SCALE);
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    int item_int_part= item->decimal_int_part();
    int item_prec = max(prev_decimal_int_part, item_int_part) + decimals;
    int precision= min(item_prec, DECIMAL_MAX_PRECISION);
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    unsigned_flag&= item->unsigned_flag;
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    max_length= my_decimal_precision_to_length_no_truncation(precision,
                                                             decimals,
                                                             unsigned_flag);
8537
  }
8538

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  switch (Field::result_merge_type(fld_type))
  {
  case STRING_RESULT:
8542
  {
8543
    const char *old_cs, *old_derivation;
8544
    uint32 old_max_chars= max_length / collation.collation->mbmaxlen;
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    old_cs= collation.collation->name;
    old_derivation= collation.derivation_name();
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    if (collation.aggregate(item->collation, MY_COLL_ALLOW_CONV))
8548
    {
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      my_error(ER_CANT_AGGREGATE_2COLLATIONS, MYF(0),
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	       old_cs, old_derivation,
	       item->collation.collation->name,
	       item->collation.derivation_name(),
	       "UNION");
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      DBUG_RETURN(TRUE);
8555
    }
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    /*
      To figure out max_length, we have to take into account possible
      expansion of the size of the values because of character set
      conversions.
     */
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    if (collation.collation != &my_charset_bin)
    {
      max_length= max(old_max_chars * collation.collation->mbmaxlen,
                      display_length(item) /
                      item->collation.collation->mbmaxlen *
                      collation.collation->mbmaxlen);
    }
    else
      set_if_bigger(max_length, display_length(item));
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    break;
8571
  }
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  case REAL_RESULT:
  {
    if (decimals != NOT_FIXED_DEC)
    {
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      /*
        For FLOAT(M,D)/DOUBLE(M,D) do not change precision
         if both fields have the same M and D
      */
      if (item->max_length != max_length_orig ||
          item->decimals != decimals_orig)
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      {
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        int delta1= max_length_orig - decimals_orig;
        int delta2= item->max_length - item->decimals;
        max_length= max(delta1, delta2) + decimals;
        if (fld_type == MYSQL_TYPE_FLOAT && max_length > FLT_DIG + 2)
        {
          max_length= MAX_FLOAT_STR_LENGTH;
          decimals= NOT_FIXED_DEC;
        } 
        else if (fld_type == MYSQL_TYPE_DOUBLE && max_length > DBL_DIG + 2)
        {
          max_length= MAX_DOUBLE_STR_LENGTH;
          decimals= NOT_FIXED_DEC;
        }
8596
      }
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    }
    else
      max_length= (fld_type == MYSQL_TYPE_FLOAT) ? FLT_DIG+6 : DBL_DIG+7;
    break;
8601
  }
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  default:
    max_length= max(max_length, display_length(item));
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  };
8605 8606
  maybe_null|= item->maybe_null;
  get_full_info(item);
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  /* Remember decimal integer part to be used in DECIMAL_RESULT handleng */
  prev_decimal_int_part= decimal_int_part();
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  DBUG_PRINT("info", ("become type: %d  len: %u  dec: %u",
                      (int) fld_type, max_length, (uint) decimals));
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  DBUG_RETURN(FALSE);
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}

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/**
  Calculate lenth for merging result for given Item type.
8617

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  @param item  Item for length detection
8619

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  @return
8621 8622
    length
*/
8623

8624
uint32 Item_type_holder::display_length(Item *item)
8625 8626
{
  if (item->type() == Item::FIELD_ITEM)
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    return ((Item_field *)item)->max_disp_length();
8628

8629
  switch (item->field_type())
8630
  {
8631 8632 8633 8634 8635 8636 8637
  case MYSQL_TYPE_DECIMAL:
  case MYSQL_TYPE_TIMESTAMP:
  case MYSQL_TYPE_DATE:
  case MYSQL_TYPE_TIME:
  case MYSQL_TYPE_DATETIME:
  case MYSQL_TYPE_YEAR:
  case MYSQL_TYPE_NEWDATE:
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  case MYSQL_TYPE_VARCHAR:
  case MYSQL_TYPE_BIT:
  case MYSQL_TYPE_NEWDECIMAL:
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  case MYSQL_TYPE_ENUM:
  case MYSQL_TYPE_SET:
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
  case MYSQL_TYPE_VAR_STRING:
  case MYSQL_TYPE_STRING:
  case MYSQL_TYPE_GEOMETRY:
8650
    return item->max_length;
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  case MYSQL_TYPE_TINY:
    return 4;
  case MYSQL_TYPE_SHORT:
    return 6;
  case MYSQL_TYPE_LONG:
8656
    return MY_INT32_NUM_DECIMAL_DIGITS;
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  case MYSQL_TYPE_FLOAT:
    return 25;
  case MYSQL_TYPE_DOUBLE:
8660
    return 53;
8661
  case MYSQL_TYPE_NULL:
8662
    return 0;
8663
  case MYSQL_TYPE_LONGLONG:
8664
    return 20;
8665 8666
  case MYSQL_TYPE_INT24:
    return 8;
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  default:
    DBUG_ASSERT(0); // we should never go there
    return 0;
  }
}
8672

8673

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/**
8675
  Make temporary table field according collected information about type
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  of UNION result.
8677

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  @param table  temporary table for which we create fields
8679

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  @return
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    created field
*/

Field *Item_type_holder::make_field_by_type(TABLE *table)
{
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  /*
    The field functions defines a field to be not null if null_ptr is not 0
  */
  uchar *null_ptr= maybe_null ? (uchar*) "" : 0;
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  Field *field;

  switch (fld_type) {
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  case MYSQL_TYPE_ENUM:
8694
    DBUG_ASSERT(enum_set_typelib);
8695
    field= new Field_enum((uchar *) 0, max_length, null_ptr, 0,
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                          Field::NONE, name,
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                          get_enum_pack_length(enum_set_typelib->count),
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                          enum_set_typelib, collation.collation);
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    if (field)
      field->init(table);
    return field;
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  case MYSQL_TYPE_SET:
    DBUG_ASSERT(enum_set_typelib);
8704
    field= new Field_set((uchar *) 0, max_length, null_ptr, 0,
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                         Field::NONE, name,
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                         get_set_pack_length(enum_set_typelib->count),
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                         enum_set_typelib, collation.collation);
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    if (field)
      field->init(table);
    return field;
8711 8712
  case MYSQL_TYPE_NULL:
    return make_string_field(table);
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  default:
    break;
8715
  }
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  return tmp_table_field_from_field_type(table, 0);
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}


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/**
8721
  Get full information from Item about enum/set fields to be able to create
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  them later.
8723

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  @param item    Item for information collection
8725 8726 8727 8728 8729 8730
*/
void Item_type_holder::get_full_info(Item *item)
{
  if (fld_type == MYSQL_TYPE_ENUM ||
      fld_type == MYSQL_TYPE_SET)
  {
8731 8732 8733
    if (item->type() == Item::SUM_FUNC_ITEM &&
        (((Item_sum*)item)->sum_func() == Item_sum::MAX_FUNC ||
         ((Item_sum*)item)->sum_func() == Item_sum::MIN_FUNC))
8734
      item = ((Item_sum*)item)->get_arg(0);
8735
    /*
8736 8737
      We can have enum/set type after merging only if we have one enum|set
      field (or MIN|MAX(enum|set field)) and number of NULL fields
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    */
    DBUG_ASSERT((enum_set_typelib &&
                 get_real_type(item) == MYSQL_TYPE_NULL) ||
                (!enum_set_typelib &&
                 item->type() == Item::FIELD_ITEM &&
                 (get_real_type(item) == MYSQL_TYPE_ENUM ||
                  get_real_type(item) == MYSQL_TYPE_SET) &&
                 ((Field_enum*)((Item_field *) item)->field)->typelib));
    if (!enum_set_typelib)
    {
      enum_set_typelib= ((Field_enum*)((Item_field *) item)->field)->typelib;
    }
  }
}


8754
double Item_type_holder::val_real()
8755 8756 8757 8758 8759 8760 8761 8762 8763 8764 8765 8766
{
  DBUG_ASSERT(0); // should never be called
  return 0.0;
}


longlong Item_type_holder::val_int()
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}

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my_decimal *Item_type_holder::val_decimal(my_decimal *)
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}
8772 8773 8774 8775 8776 8777 8778

String *Item_type_holder::val_str(String*)
{
  DBUG_ASSERT(0); // should never be called
  return 0;
}

8779 8780 8781 8782 8783 8784 8785 8786
void Item_result_field::cleanup()
{
  DBUG_ENTER("Item_result_field::cleanup()");
  Item::cleanup();
  result_field= 0;
  DBUG_VOID_RETURN;
}

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/**
  Dummy error processor used by default by Name_resolution_context.
8789

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  @note
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    do nothing
*/

void dummy_error_processor(THD *thd, void *data)
{}

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/**
  Wrapper of hide_view_error call for Name_resolution_context error
  processor.
8800

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  @note
8802 8803 8804 8805 8806 8807 8808 8809
    hide view underlying tables details in error messages
*/

void view_error_processor(THD *thd, void *data)
{
  ((TABLE_LIST *)data)->hide_view_error(thd);
}

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/*****************************************************************************
** Instantiate templates
*****************************************************************************/

8814
#ifdef HAVE_EXPLICIT_TEMPLATE_INSTANTIATION
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template class List<Item>;
template class List_iterator<Item>;
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template class List_iterator_fast<Item>;
8818
template class List_iterator_fast<Item_field>;
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template class List<List_item>;
#endif