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

1 files changed, 26 insertions, 54 deletions

diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index ac304554d78..384d05ad94e 100644
--- a/sql/sql_parse.cc
+++ b/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 @@ error:
 */
 
 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;