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

@@ -37,8 +37,8 @@ char NEAR errbuff[NRERRBUFFS][ERRMSGSIZE];
     The following subset of printf format is supported:
     "%[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.
+    Additionally "%.*s" is supported and "%.*[ud]" is correctly parsed but
+    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 */
@@ -76,10 +76,11 @@ int my_error(int nr,myf MyFlags, ...)
     }
     else
     {
-      /* 
-        Skip size/precision flags to be compatible with printf. 
-        The only size/precision flag supported is "%.*s". 
-        "%.*u" and "%.*d" cause 
+      /*
+        Skip size/precision flags to be compatible with printf.
+        The only size/precision flag supported is "%.*s".
+        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== '.')
@@ -94,52 +95,52 @@ int my_error(int nr,myf MyFlags, ...)
           prec_supplied= 1;
         }
       }
-       
+
       if (!prec_supplied)
       {
-        while (my_isdigit(&my_charset_latin1, *tpos) || *tpos == '.' || 
+        while (my_isdigit(&my_charset_latin1, *tpos) || *tpos == '.' ||
                *tpos == '-')
-	 tpos++;
-        
-        if (*tpos == 'l')				/* Skipp 'l' argument */
+	  tpos++;
+
+        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) {
@@ -1666,7 +1728,7 @@ bool Item::send(Protocol *protocol, String *buffer)
   }
   case MYSQL_TYPE_TINY:
   {
-    longlong nr;  
+    longlong nr;
     nr= val_int();
     if (!null_value)
       result= protocol->store_tiny(nr);

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

@@ -2703,17 +2703,17 @@ void Item_func_get_user_var::fix_length_and_dec()
   maybe_null=1;
   decimals=NOT_FIXED_DEC;
   max_length=MAX_BLOB_WIDTH;
-  
+
   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();
-      
+
   return;
 }
 

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_class.cc

@@ -233,7 +233,7 @@ THD::THD():user_time(0), current_statement(0), is_fatal_error(0),
 			  16);
   else
     bzero((char*) &user_var_events, sizeof(user_var_events));
-  
+
   /* Protocol */
   protocol= &protocol_simple;			// Default protocol
   protocol_simple.init(this);

sql/sql_parse.cc

@@ -1976,86 +1976,59 @@ mysql_execute_command(THD *thd)
     break;
   }
   case SQLCOM_PREPARE:
-  {   
+  {
     char *query_str;
     uint query_len;
     if (lex->prepared_stmt_code_is_varref)
     {
       /* 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;
       /*
-        Convert @var contents to string in connection character set. Although 
-        it is known that int/real/NULL value cannot be a valid query we still 
-        convert it for error messages to uniform.  
+        Convert @var contents to string in connection character set. Although
+        it is known that int/real/NULL value cannot be a valid query we still
+        convert it for error messages to uniform.
       */
-      if ((entry= 
-             (user_var_entry*)hash_search(&thd->user_vars, 
+      if ((entry=
+             (user_var_entry*)hash_search(&thd->user_vars,
                                           (byte*)lex->prepared_stmt_code.str,
                                           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);
-      }
-       
-      query_len = need_conversion? (buf_len * to_cs->mbmaxlen) : buf_len;
+        str.set("NULL", 4, &my_charset_latin1);
+      need_conversion=
+        String::needs_conversion(str.length(), str.charset(), to_cs, &unused);
+
+      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
     {
       query_str= lex->prepared_stmt_code.str;
       query_len= lex->prepared_stmt_code.length;
-      DBUG_PRINT("info", ("PREPARE: %.*s FROM '%.*s' \n", 
+      DBUG_PRINT("info", ("PREPARE: %.*s FROM '%.*s' \n",
                           lex->prepared_stmt_name.length,
                           lex->prepared_stmt_name.str,
                           query_len, query_str));
@@ -2068,7 +2041,7 @@ mysql_execute_command(THD *thd)
   }
   case SQLCOM_EXECUTE:
   {
-    DBUG_PRINT("info", ("EXECUTE: %.*s\n", 
+    DBUG_PRINT("info", ("EXECUTE: %.*s\n",
                         lex->prepared_stmt_name.length,
                         lex->prepared_stmt_name.str));
     mysql_sql_stmt_execute(thd, &lex->prepared_stmt_name);
@@ -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_yacc.yy

@@ -764,12 +764,12 @@ verb_clause:
 	| checksum
 	| commit
 	| create
-        | deallocate 
+        | deallocate
 	| delete
 	| describe
 	| do
 	| drop
-        | execute 
+        | execute
 	| flush
 	| grant
 	| handler
@@ -781,7 +781,7 @@ verb_clause:
 	| optimize
         | keycache
 	| preload
-        | prepare 
+        | prepare
 	| purge
 	| rename
 	| repair
@@ -803,7 +803,7 @@ verb_clause:
         ;
 
 deallocate:
-        DEALLOCATE_SYM PREPARE_SYM ident 
+        DEALLOCATE_SYM PREPARE_SYM ident
         {
           THD *thd=YYTHD;
           LEX *lex= thd->lex;
@@ -845,7 +845,7 @@ prepare_src:
           lex->prepared_stmt_code= $2;
           lex->prepared_stmt_code_is_varref= true;
         };
-        
+
 execute:
         EXECUTE_SYM ident
         {