Preparation to thread specific default charset

sql/sql_class.cc

@@ -108,6 +108,7 @@ THD::THD():user_time(0), fatal_error(0),
   file_id = 0;
   cond_count=0;
   db_charset=default_charset_info;
+  thd_charset=default_charset_info;
   mysys_var=0;
 #ifndef DBUG_OFF
   dbug_sentry=THD_SENTRY_MAGIC;

sql/sql_class.h

@@ -481,6 +481,7 @@ public:
   table_map  used_tables;
   USER_CONN *user_connect;
   CHARSET_INFO *db_charset;   
+  CHARSET_INFO *thd_charset;
   List	     <MYSQL_ERROR> warn_list;  
   uint	     warn_count[(uint) MYSQL_ERROR::WARN_LEVEL_END];
   uint	     total_warn_count, old_total_warn_count;

sql/sql_db.cc

@@ -592,7 +592,7 @@ bool mysql_change_db(THD *thd, const char *name)
   strmov(path+unpack_dirname(path,path), MY_DB_OPT_FILE);
   load_db_opt(path, &create);
   thd->db_charset=create.table_charset;
-
+  thd->thd_charset=thd->db_charset ? thd->db_charset : default_charset_info;
   DBUG_RETURN(0);
 }
 

sql/sql_yacc.yy

@@ -3309,13 +3309,13 @@ opt_ignore_lines:
 /* Common definitions */
 
 text_literal:
-	TEXT_STRING { $$ = new Item_string($1.str,$1.length,default_charset_info); }
+	TEXT_STRING { $$ = new Item_string($1.str,$1.length,current_thd->thd_charset); }
 	| UNDERSCORE_CHARSET TEXT_STRING { $$ = new Item_string($2.str,$2.length,Lex->charset); }
 	| text_literal TEXT_STRING
 	{ ((Item_string*) $1)->append($2.str,$2.length); };
 
 text_string:
-	TEXT_STRING	{ $$=  new String($1.str,$1.length,default_charset_info); }
+	TEXT_STRING	{ $$=  new String($1.str,$1.length,current_thd->thd_charset); }
 	| HEX_NUM
 	  {
 	    Item *tmp = new Item_varbinary($1.str,$1.length);