Adding Item_string_sys and Item_string_ascii to reduce duplicate code

sql/item.h

@@ -2929,6 +2929,32 @@ class Item_string_with_introducer :public Item_string
 };
 
 
+class Item_string_sys :public Item_string
+{
+public:
+  Item_string_sys(const char *str, uint length)
+    :Item_string(str, length, system_charset_info)
+  { }
+  Item_string_sys(const char *str)
+    :Item_string(str, strlen(str), system_charset_info)
+  { }
+};
+
+
+class Item_string_ascii :public Item_string
+{
+public:
+  Item_string_ascii(const char *str, uint length)
+    :Item_string(str, length, &my_charset_latin1,
+                 DERIVATION_COERCIBLE, MY_REPERTOIRE_ASCII)
+  { }
+  Item_string_ascii(const char *str)
+    :Item_string(str, strlen(str), &my_charset_latin1,
+                 DERIVATION_COERCIBLE, MY_REPERTOIRE_ASCII)
+  { }
+};
+
+
 longlong 
 longlong_from_string_with_check(CHARSET_INFO *cs, const char *cptr,
                                 const char *end);

sql/sql_acl.cc

@@ -7551,7 +7551,7 @@ bool mysql_show_grants(THD *thd, LEX_USER *lex_user)
   }
   DBUG_ASSERT(rolename || username);
 
-  Item_string *field=new Item_string("",0,&my_charset_latin1);
+  Item_string *field=new Item_string_ascii("", 0);
   List<Item> field_list;
   field->name=buff;
   field->max_length=1024;

sql/sql_explain.cc

@@ -203,15 +203,13 @@ bool Explain_query::print_explain_str(THD *thd, String *out_str)
 
 static void push_str(List<Item> *item_list, const char *str)
 {
-  item_list->push_back(new Item_string(str,
-                                      strlen(str), system_charset_info));
+  item_list->push_back(new Item_string_sys(str));
 }
 
 
 static void push_string(List<Item> *item_list, String *str)
 {
-  item_list->push_back(new Item_string(str->ptr(), str->length(),
-                       system_charset_info));
+  item_list->push_back(new Item_string_sys(str->ptr(), str->length()));
 }
 
 
@@ -262,8 +260,7 @@ int Explain_union::print_explain(Explain_query *query,
       len+= lastop;
       table_name_buffer[len - 1]= '>';  // change ',' to '>'
     }
-    const CHARSET_INFO *cs= system_charset_info;
-    item_list.push_back(new Item_string(table_name_buffer, len, cs));
+    item_list.push_back(new Item_string_sys(table_name_buffer, len));
   }
   
   /* `partitions` column */
@@ -298,8 +295,7 @@ int Explain_union::print_explain(Explain_query *query,
   {
     extra_buf.append(STRING_WITH_LEN("Using filesort"));
   }
-  const CHARSET_INFO *cs= system_charset_info;
-  item_list.push_back(new Item_string(extra_buf.ptr(), extra_buf.length(), cs));
+  item_list.push_back(new Item_string_sys(extra_buf.ptr(), extra_buf.length()));
 
   //output->unit.offset_limit_cnt= 0; 
   if (output->send_data(item_list))
@@ -349,12 +345,10 @@ int Explain_select::print_explain(Explain_query *query,
   if (message)
   {
     List<Item> item_list;
-    const CHARSET_INFO *cs= system_charset_info;
     Item *item_null= new Item_null();
 
     item_list.push_back(new Item_int((int32) select_id));
-    item_list.push_back(new Item_string(select_type,
-                                        strlen(select_type), cs));
+    item_list.push_back(new Item_string_sys(select_type));
     for (uint i=0 ; i < 7; i++)
       item_list.push_back(item_null);
     if (explain_flags & DESCRIBE_PARTITIONS)
@@ -362,7 +356,7 @@ int Explain_select::print_explain(Explain_query *query,
     if (explain_flags & DESCRIBE_EXTENDED)
       item_list.push_back(item_null);
 
-    item_list.push_back(new Item_string(message,strlen(message),cs));
+    item_list.push_back(new Item_string_sys(message));
 
     if (output->send_data(item_list))
       return 1;
@@ -560,7 +554,7 @@ int Explain_table_access::print_explain(select_result_sink *output, uint8 explai
     extra_buf.append(STRING_WITH_LEN("Using filesort"));
   }
 
-  item_list.push_back(new Item_string(extra_buf.ptr(), extra_buf.length(), cs));
+  item_list.push_back(new Item_string_sys(extra_buf.ptr(), extra_buf.length()));
 
   if (output->send_data(item_list))
     return 1;

sql/sql_help.cc

@@ -626,7 +626,7 @@ SQL_SELECT *prepare_select_for_name(THD *thd, const char *mask, uint mlen,
 {
   Item *cond= new Item_func_like(new Item_field(pfname),
 				 new Item_string(mask,mlen,pfname->charset()),
-				 new Item_string("\\",1,&my_charset_latin1),
+				 new Item_string_ascii("\\"),
                                  FALSE);
   if (thd->is_fatal_error)
     return 0;					// OOM

sql/sql_select.cc

@@ -22950,13 +22950,11 @@ int print_explain_message_line(select_result_sink *result,
                                ha_rows *rows,
                                const char *message)
 {
-  const CHARSET_INFO *cs= system_charset_info;
   Item *item_null= new Item_null();
   List<Item> item_list;
 
   item_list.push_back(new Item_int((int32) select_number));
-  item_list.push_back(new Item_string(select_type,
-                                      strlen(select_type), cs));
+  item_list.push_back(new Item_string_sys(select_type));
   /* `table` */
   item_list.push_back(item_null);
   
@@ -22983,7 +22981,7 @@ int print_explain_message_line(select_result_sink *result,
 
   /* `Extra` */
   if (message)
-    item_list.push_back(new Item_string(message,strlen(message),cs));
+    item_list.push_back(new Item_string_sys(message));
   else
     item_list.push_back(item_null);
 
@@ -23042,45 +23040,39 @@ int print_explain_row(select_result_sink *result,
                       ha_rows *rows,
                       const char *extra)
 {
-  const CHARSET_INFO *cs= system_charset_info;
   Item *item_null= new Item_null();
   List<Item> item_list;
   Item *item;
 
   item_list.push_back(new Item_int((int32) select_number));
-  item_list.push_back(new Item_string(select_type,
-                                      strlen(select_type), cs));
-  item_list.push_back(new Item_string(table_name,
-                                      strlen(table_name), cs));
+  item_list.push_back(new Item_string_sys(select_type));
+  item_list.push_back(new Item_string_sys(table_name));
   if (options & DESCRIBE_PARTITIONS)
   {
     if (partitions)
     {
-      item_list.push_back(new Item_string(partitions,
-                                          strlen(partitions), cs));
+      item_list.push_back(new Item_string_sys(partitions));
     }
     else
       item_list.push_back(item_null);
   }
   
   const char *jtype_str= join_type_str[jtype];
-  item_list.push_back(new Item_string(jtype_str,
-                                      strlen(jtype_str), cs));
+  item_list.push_back(new Item_string_sys(jtype_str));
   
-  item= possible_keys? new Item_string(possible_keys, strlen(possible_keys),
-                                      cs) : item_null;
+  item= possible_keys? new Item_string_sys(possible_keys) : item_null;
   item_list.push_back(item);
   
   /* 'index */
-  item= index ? new Item_string(index, strlen(index), cs) : item_null;
+  item= index ? new Item_string_sys(index) : item_null;
   item_list.push_back(item);
   
   /* 'key_len */
-  item= key_len ? new Item_string(key_len, strlen(key_len), cs) : item_null;
+  item= key_len ? new Item_string_sys(key_len) : item_null;
   item_list.push_back(item);
   
   /* 'ref' */
-  item= ref ? new Item_string(ref, strlen(ref), cs) : item_null;
+  item= ref ? new Item_string_sys(ref) : item_null;
   item_list.push_back(item);
 
   /* 'rows' */
@@ -23099,7 +23091,7 @@ int print_explain_row(select_result_sink *result,
   
   /* 'Extra' */
   if (extra)
-    item_list.push_back(new Item_string(extra, strlen(extra), cs));
+    item_list.push_back(new Item_string_sys(extra));
   else
     item_list.push_back(item_null);
 
@@ -23112,7 +23104,6 @@ int print_explain_row(select_result_sink *result,
 int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
                                SELECT_LEX *select_lex, uint8 explain_flags)
 {
-  const CHARSET_INFO *cs= system_charset_info;
   Item *item_null= new Item_null();
   List<Item> item_list;
   if (on_the_fly)
@@ -23129,9 +23120,7 @@ int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
   /* id */
   item_list.push_back(new Item_null);
   /* select_type */
-  item_list.push_back(new Item_string(select_lex->type,
-                                      strlen(select_lex->type),
-                                      cs));
+  item_list.push_back(new Item_string_sys(select_lex->type));
   /* table */
   {
     SELECT_LEX *sl= select_lex->master_unit()->first_select();
@@ -23153,15 +23142,14 @@ int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
       len+= lastop;
       table_name_buffer[len - 1]= '>';  // change ',' to '>'
     }
-    item_list.push_back(new Item_string(table_name_buffer, len, cs));
+    item_list.push_back(new Item_string_sys(table_name_buffer, len));
   }
   /* partitions */
   if (explain_flags & DESCRIBE_PARTITIONS)
     item_list.push_back(item_null);
   /* type */
-  item_list.push_back(new Item_string(join_type_str[JT_ALL],
-                                        strlen(join_type_str[JT_ALL]),
-                                        cs));
+  item_list.push_back(new Item_string_sys(join_type_str[JT_ALL]));
+
   /* possible_keys */
   item_list.push_back(item_null);
   /* key*/
@@ -23177,10 +23165,9 @@ int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
   item_list.push_back(item_null);
   /* extra */
   if (select_lex->master_unit()->global_parameters->order_list.first)
-    item_list.push_back(new Item_string("Using filesort",
-                                        14, cs));
+    item_list.push_back(new Item_string_sys("Using filesort", 14));
   else
-    item_list.push_back(new Item_string("", 0, cs));
+    item_list.push_back(new Item_string_sys("", 0));
 
   if (result->send_data(item_list))
     return 1;

sql/sql_yacc.yy

@@ -11124,8 +11124,8 @@ opt_escape:
           {
             Lex->escape_used= FALSE;
             $$= ((thd->variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES) ?
-                 new (thd->mem_root) Item_string("", 0, &my_charset_latin1) :
-                 new (thd->mem_root) Item_string("\\", 1, &my_charset_latin1));
+                 new (thd->mem_root) Item_string_ascii("", 0) :
+                 new (thd->mem_root) Item_string_ascii("\\", 1));
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
@@ -14792,19 +14792,19 @@ set_expr_or_default:
         | DEFAULT { $$=0; }
         | ON
           {
-            $$=new (thd->mem_root) Item_string("ON",  2, system_charset_info);
+            $$=new (thd->mem_root) Item_string_sys("ON",  2);
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
         | ALL
           {
-            $$=new (thd->mem_root) Item_string("ALL", 3, system_charset_info);
+            $$=new (thd->mem_root) Item_string_sys("ALL", 3);
             if ($$ == NULL)
               MYSQL_YYABORT;
           }
         | BINARY
           {
-            $$=new (thd->mem_root) Item_string("binary", 6, system_charset_info);
+            $$=new (thd->mem_root) Item_string_sys("binary", 6);
             if ($$ == NULL)
               MYSQL_YYABORT;
           }