Post review fixes for "SQL Syntax for Prepared Statements".

mysql-test/r/ps.result:
  Better error message
mysys/my_error.c:
  Comments added
sql/item.cc:
  Moved a chunk of code from sql_prepare.cc to Item_param::set_from_user_var
sql/item.h:
  Moved a chunk of code from sql_prepare.cc to Item_param::set_from_user_var
sql/item_func.cc:
  Code cleanup
sql/mysql_priv.h:
  Code cleanup
sql/sql_class.cc:
  Code cleanup
sql/sql_parse.cc:
  use user_var_entry::val_str in PREPARE stmt FROM @var.
sql/sql_prepare.cc:
  Post-review fixes and code cleanup.
sql/sql_yacc.yy:
  Coding style fixes

mysql-test/r/ps.result

@@ -23,7 +23,7 @@ a	b
 deallocate prepare no_such_statement;
 ERROR HY000: Unknown prepared statement handler (no_such_statement) given to DEALLOCATE PREPARE
 execute stmt1;
-ERROR HY000: Wrong arguments to mysql_execute
+ERROR HY000: Wrong arguments to EXECUTE
 prepare stmt2 from 'prepare nested_stmt from "select 1"';
 ERROR 42000: You have an error in your SQL syntax.  Check the manual that corresponds to your MySQL server version for the right syntax to use near '"select 1"' at line 1
 prepare stmt2 from 'execute stmt1';

mysys/my_error.c

@@ -38,7 +38,7 @@ char NEAR errbuff[NRERRBUFFS][ERRMSGSIZE];
     "%[0-9.-]*l?[sdu]", where all length flags are parsed but ignored.
 
     Additionally "%.*s" is supported and "%.*[ud]" is correctly parsed but
-    length value is ignored.
+    the length value is ignored.
 */
 
 int my_error(int nr,myf MyFlags, ...)
@@ -49,7 +49,7 @@ int my_error(int nr,myf MyFlags, ...)
   reg2 char	*endpos;
   char		* par;
   char		ebuff[ERRMSGSIZE+20];
-  int           prec_chars;
+  int           prec_chars; /* output precision */
   my_bool       prec_supplied;
   DBUG_ENTER("my_error");
   LINT_INIT(prec_chars); /* protected by prec_supplied */
@@ -79,7 +79,8 @@ int my_error(int nr,myf MyFlags, ...)
       /*
         Skip size/precision flags to be compatible with printf.
         The only size/precision flag supported is "%.*s".
-        "%.*u" and "%.*d" cause 
+        If "%.*u" or "%.*d" are encountered, the precision number is read
+        from the variable argument list but its value is ignored.
       */
       prec_supplied= 0;
       if (*tpos== '.')
@@ -101,45 +102,45 @@ int my_error(int nr,myf MyFlags, ...)
                *tpos == '-')
 	  tpos++;
 
-        if (*tpos == 'l')				/* Skipp 'l' argument */
+        if (*tpos == 'l')				/* Skip 'l' argument */
 	  tpos++;
       }
 
       if (*tpos == 's')				/* String parameter */
       {
-	par = va_arg(ap, char *);
-	plen = (uint) strlen(par);
+	par= va_arg(ap, char *);
+	plen= (uint) strlen(par);
         if (prec_supplied && prec_chars > 0)
           plen= min((uint)prec_chars, plen);
 	if (olen + plen < ERRMSGSIZE+2)		/* Replace if possible */
 	{
-          memcpy(endpos,par, plen);
-          endpos += plen;
+          strmake(endpos, par, plen);
+          endpos+= plen;
           tpos++;
-          olen+=plen-2;
+          olen+= plen-2;
           continue;
 	}
       }
       else if (*tpos == 'd' || *tpos == 'u')	/* Integer parameter */
       {
 	register int iarg;
-	iarg = va_arg(ap, int);
+	iarg= va_arg(ap, int);
 	if (*tpos == 'd')
 	  plen= (uint) (int10_to_str((long) iarg, endpos, -10) - endpos);
 	else
 	  plen= (uint) (int10_to_str((long) (uint) iarg, endpos, 10) - endpos);
 	if (olen + plen < ERRMSGSIZE+2) /* Replace parameter if possible */
 	{
-	  endpos+=plen;
+	  endpos+= plen;
 	  tpos++;
-	  olen+=plen-2;
+	  olen+= plen-2;
 	  continue;
 	}
       }
     }
-    *endpos++='%';		/* % used as % or unknown code */
+    *endpos++= '%';		/* % used as % or unknown code */
   }
-  *endpos='\0';			/* End of errmessage */
+  *endpos= '\0';			/* End of errmessage */
   va_end(ap);
   DBUG_RETURN((*error_handler_hook)(nr, ebuff, MyFlags));
 }

sql/item.cc

@@ -255,7 +255,7 @@ bool Item::get_time(TIME *ltime)
   return 0;
 }
 
-CHARSET_INFO * Item::default_charset() 
+CHARSET_INFO *Item::default_charset()
 {
   return current_thd->variables.collation_connection;
 }
@@ -735,6 +735,70 @@ bool Item_param::set_longdata(const char *str, ulong length)
 }
 
 
+/*
+  Set parameter value from user variable value.
+
+  SYNOPSIS
+   set_from_user_var
+     thd   Current thread
+     entry User variable structure (NULL means use NULL value)
+
+  RETURN
+    0 OK
+    1 Out of memort
+*/
+
+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;
+    switch (entry->type)
+    {
+      case REAL_RESULT:
+        set_double(*(double*)entry->value);
+        break;
+      case INT_RESULT:
+        set_int(*(longlong*)entry->value, 21);
+        break;
+      case STRING_RESULT:
+        {
+          CHARSET_INFO *fromcs= entry->collation.collation;
+          CHARSET_INFO *tocs= thd->variables.collation_connection;
+          uint32 dummy_offset;
+
+          value.cs_info.character_set_client= fromcs;
+          /*
+            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;
+          item_result_type= STRING_RESULT;
+
+          if (set_str((const char *)entry->value, entry->length))
+            DBUG_RETURN(1);
+        }
+        break;
+      default:
+        DBUG_ASSERT(0);
+        set_null();
+    }
+  }
+  else
+    set_null();
+
+  DBUG_RETURN(0);
+}
+
 /*
     Resets parameter after execution.
   
@@ -767,8 +831,6 @@ void Item_param::reset()
 
 int Item_param::save_in_field(Field *field, bool no_conversions)
 {
-  DBUG_ASSERT(current_thd->command == COM_EXECUTE);
-
   field->set_notnull();
 
   switch (state) {

sql/item.h

@@ -489,6 +489,7 @@ class Item_param :public Item
   bool set_str(const char *str, ulong length);
   bool set_longdata(const char *str, ulong length);
   void set_time(TIME *tm, timestamp_type type, uint32 max_length_arg);
+  bool set_from_user_var(THD *thd, const user_var_entry *entry);
   void reset();
   /*
     Assign placeholder value from bind data.

sql/item_func.cc

@@ -2706,10 +2706,10 @@ void Item_func_get_user_var::fix_length_and_dec()
 
   error= get_var_with_binlog(thd, name, &var_entry);
 
-  if (!var_entry)
-    null_value= 1;
-  else
+  if (var_entry)
     collation.set(var_entry->collation);
+  else
+    null_value= 1;
 
   if (error)
     thd->fatal_error();

sql/mysql_priv.h

@@ -348,6 +348,7 @@ inline THD *_current_thd(void)
 #include "field.h"				/* Field definitions */
 #include "protocol.h"
 #include "sql_udf.h"
+class user_var_entry;
 #include "item.h"
 typedef Comp_creator* (*chooser_compare_func_creator)(bool invert);
 /* sql_parse.cc */

sql/sql_parse.cc

@@ -1983,12 +1983,9 @@ mysql_execute_command(THD *thd)
     {
       /* This is PREPARE stmt FROM @var. */
       String str;
+      String *pstr;
       CHARSET_INFO *to_cs= thd->variables.collation_connection;
-      CHARSET_INFO *from_cs;
-      const char *buf;
-      uint  buf_len;
       bool need_conversion;
-      LINT_INIT(from_cs); /* protected by need_conversion */
       user_var_entry *entry;
       uint32 unused;
       /*
@@ -2002,53 +1999,29 @@ mysql_execute_command(THD *thd)
                                           lex->prepared_stmt_code.length))
           && entry->value)
       {
-        switch (entry->type)
-        {
-          case REAL_RESULT:
-            str.set(*(double*)entry->value, NOT_FIXED_DEC, to_cs);
-            buf_len= str.length();
-            buf= str.ptr();
-            need_conversion= false;
-            break;
-          case INT_RESULT:
-            str.set(*(longlong*)entry->value, to_cs);
-            buf_len= str.length();
-            buf= str.ptr();
-            need_conversion= false;
-            break;
-          case STRING_RESULT:
-            buf_len= entry->length;
-            buf= entry->value;
-            from_cs = entry->collation.collation;
-            need_conversion= String::needs_conversion(entry->length, from_cs,
-                                                      to_cs, &unused);
-            break;
-          default:
-            buf= "";
-            need_conversion= false;
-            buf_len= 0;
-            DBUG_ASSERT(0);
-        }
+        String *pstr;
+        my_bool is_var_null;
+        pstr= entry->val_str(&is_var_null, &str, NOT_FIXED_DEC);
+        DBUG_ASSERT(!is_var_null);
+        if (!pstr)
+          send_error(thd, ER_OUT_OF_RESOURCES);
+        DBUG_ASSERT(pstr == &str);
       }
       else
-      {
-        from_cs= &my_charset_bin;
-        str.set("NULL", 4, from_cs);
-        buf= str.ptr();
-        buf_len= str.length();
-        need_conversion= String::needs_conversion(str.length(), from_cs,
-                                                  to_cs, &unused);
-      }
+        str.set("NULL", 4, &my_charset_latin1);
+      need_conversion=
+        String::needs_conversion(str.length(), str.charset(), to_cs, &unused);
 
-      query_len = need_conversion? (buf_len * to_cs->mbmaxlen) : buf_len;
+      query_len= need_conversion? (str.length() * to_cs->mbmaxlen) :
+                                  str.length();
       if (!(query_str= alloc_root(&thd->mem_root, query_len+1)))
         send_error(thd, ER_OUT_OF_RESOURCES);
 
       if (need_conversion)
-        query_len= copy_and_convert(query_str, query_len, to_cs, buf, buf_len,
-                                    from_cs);
+        query_len= copy_and_convert(query_str, query_len, to_cs, str.ptr(),
+                                    str.length(), str.charset());
       else
-        memcpy(query_str, buf, query_len);
+        memcpy(query_str, str.ptr(), str.length());
       query_str[query_len]= 0;
     }
     else
@@ -3559,7 +3532,6 @@ purposes internal to the MySQL server", MYF(0));
 */
 
 int check_one_table_access(THD *thd, ulong privilege, TABLE_LIST *tables)
-
 {
   if (check_access(thd, privilege, tables->db, &tables->grant.privilege,0,0))
     return 1;

sql/sql_prepare.cc

@@ -804,65 +804,20 @@ static bool insert_params_from_vars(Prepared_statement *stmt,
   Item_param **end= begin + stmt->param_count;
   user_var_entry *entry;
   LEX_STRING *varname;
+  List_iterator<LEX_STRING> var_it(varnames);
   DBUG_ENTER("insert_params_from_vars");
 
-  List_iterator<LEX_STRING> var_it(varnames);
   for (Item_param **it= begin; it < end; ++it)
   {
     Item_param *param= *it;
     varname= var_it++;
-    if ((entry= (user_var_entry*)hash_search(&stmt->thd->user_vars, 
+    entry= (user_var_entry*)hash_search(&stmt->thd->user_vars,
                                         (byte*) varname->str,
-                                             varname->length))
-        && entry->value)
-    {
-      param->item_result_type= entry->type;
-      switch (entry->type)
-      {
-        case REAL_RESULT:
-          param->set_double(*(double*)entry->value);
-          break;
-        case INT_RESULT:
-          param->set_int(*(longlong*)entry->value, 21);
-          break;
-        case STRING_RESULT:
-          {
-            CHARSET_INFO *fromcs= entry->collation.collation;
-            CHARSET_INFO *tocs= stmt->thd->variables.collation_connection;
-            uint32 dummy_offset;
-
-            param->value.cs_info.character_set_client= fromcs;
-
-            /*
-              Setup source and destination character sets so that they
-              are different only if conversion is necessary: this will
-              make later checks easier.
-            */
-            param->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.
-            */
-            param->item_type= Item::STRING_ITEM;
-            param->item_result_type= STRING_RESULT;
-
-            if (param->set_str((const char *)entry->value, entry->length))
+                                         varname->length);
+    if (param->set_from_user_var(stmt->thd, entry) ||
+        param->convert_str_value(stmt->thd))
       DBUG_RETURN(1);
   }
-          break;
-        default:
-          DBUG_ASSERT(0);
-          param->set_null();
-      }
-    }
-    else
-      param->set_null();
-
-    if (param->convert_str_value(stmt->thd))
-      DBUG_RETURN(1);                           /* out of memory */
-  }
   DBUG_RETURN(0);
 }
 
@@ -902,52 +857,9 @@ static bool insert_params_from_vars_with_log(Prepared_statement *stmt,
     if (get_var_with_binlog(stmt->thd, *varname, &entry))
         DBUG_RETURN(1);
     DBUG_ASSERT(entry);
-    if (entry->value)
-    {
-      param->item_result_type= entry->type;
-      switch (entry->type)
-      {
-        case REAL_RESULT:
-          param->set_double(*(double*)entry->value);
-          break;
-        case INT_RESULT:
-          param->set_int(*(longlong*)entry->value, 21);
-          break;
-        case STRING_RESULT:
-          {
-            CHARSET_INFO *fromcs= entry->collation.collation;
-            CHARSET_INFO *tocs= stmt->thd->variables.collation_connection;
-            uint32 dummy_offset;
-
-            param->value.cs_info.character_set_client= fromcs;
-
-            /*
-              Setup source and destination character sets so that they
-              are different only if conversion is necessary: this will
-              make later checks easier.
-            */
-            param->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.
-            */
-            param->item_type= Item::STRING_ITEM;
-            param->item_result_type= STRING_RESULT;
 
-            if (param->set_str((const char *)entry->value, entry->length))
+    if (param->set_from_user_var(stmt->thd, entry))
       DBUG_RETURN(1);
-          }
-          break;
-        default:
-          DBUG_ASSERT(0);
-          param->set_null();
-      }
-    }
-    else
-      param->set_null();
-
     /* Insert @'escaped-varname' instead of parameter in the query */
     char *buf, *ptr;
     str.length(0);
@@ -1837,13 +1749,21 @@ static void reset_stmt_params(Prepared_statement *stmt)
   Executes previously prepared query.
   If there is any parameters, then replace markers with the data supplied
   from client, and then execute the query.
-  SYNOPSYS
+  SYNOPSIS
     mysql_stmt_execute()
+      thd            Current thread
+      packet         Query string
+      packet_length  Query string length, including terminator character.
 */
 
 void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
 {
   ulong stmt_id= uint4korr(packet);
+  /*
+    Query text for binary log, or empty string if the query is not put into
+    binary log.
+  */
+  String expanded_query;
 #ifndef EMBEDDED_LIBRARY
   uchar *packet_end= (uchar *) packet + packet_length - 1;
 #endif
@@ -1865,7 +1785,6 @@ void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
     DBUG_VOID_RETURN;
   }
 
-  String expanded_query; 
 #ifndef EMBEDDED_LIBRARY
   if (stmt->param_count)
   {
@@ -1905,6 +1824,10 @@ void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
 void mysql_sql_stmt_execute(THD *thd, LEX_STRING *stmt_name)
 {
   Prepared_statement *stmt;
+  /*
+    Query text for binary log, or empty string if the query is not put into
+    binary log.
+  */
   String expanded_query;
   DBUG_ENTER("mysql_sql_stmt_execute");
 
@@ -1918,20 +1841,19 @@ void mysql_sql_stmt_execute(THD *thd, LEX_STRING *stmt_name)
 
   if (stmt->param_count != thd->lex->prepared_stmt_params.elements)
   {
-    my_error(ER_WRONG_ARGUMENTS, MYF(0), "mysql_execute");
+    my_error(ER_WRONG_ARGUMENTS, MYF(0), "EXECUTE");
     send_error(thd);
     DBUG_VOID_RETURN;
   }
-  /* Item_param allows setting parameters in COM_EXECUTE only */
-  thd->command= COM_EXECUTE;
 
   thd->free_list= NULL;
   thd->stmt_backup.set_statement(thd);
   thd->set_statement(stmt);
-  if (stmt->set_params_from_vars(stmt, thd->stmt_backup.lex->prepared_stmt_params,
+  if (stmt->set_params_from_vars(stmt,
+                                 thd->stmt_backup.lex->prepared_stmt_params,
                                  &expanded_query))
   {
-    my_error(ER_WRONG_ARGUMENTS, MYF(0), "mysql_execute");
+    my_error(ER_WRONG_ARGUMENTS, MYF(0), "EXECUTE");
     send_error(thd);
   }
   execute_stmt(thd, stmt, &expanded_query);
@@ -1980,10 +1902,7 @@ static void execute_stmt(THD *thd, Prepared_statement *stmt,
   if (!(specialflag & SPECIAL_NO_PRIOR))
     my_pthread_setprio(pthread_self(), WAIT_PRIOR);
 
-  /* 
-    Free Items that were created during this execution of the PS by query
-    optimizer.
-  */
+  /* Free Items that were created during this execution of the PS. */
   free_items(thd->free_list);
   cleanup_items(stmt->free_list);
   reset_stmt_params(stmt);
@@ -2138,24 +2057,6 @@ Prepared_statement::Prepared_statement(THD *thd_arg)
   get_longdata_error(0)
 {
   *last_error= '\0';
-  if (mysql_bin_log.is_open()) //psergey-todo: remove this!
-  {
-    set_params_from_vars= insert_params_from_vars_with_log;
-#ifndef EMBEDDED_LIBRARY
-    set_params= insert_params_withlog;
-#else
-    set_params_data= emb_insert_params_withlog;
-#endif
-  }
-  else
-  {
-    set_params_from_vars= insert_params_from_vars;
-#ifndef EMBEDDED_LIBRARY
-    set_params= insert_params;
-#else
-    set_params_data= emb_insert_params;
-#endif
-  }
 }
 
 void Prepared_statement::setup_set_params()