Deriving Item_row from Item_args and sharing more code

between Item_func, Item_sum, Item_row.

1 files changed, 27 insertions, 11 deletions

diff --git a/sql/item_row.h b/sql/item_row.h
index 31efc015909..1bec6212715 100644
--- a/sql/item_row.h
+++ b/sql/item_row.h
@@ -17,20 +17,31 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
-class Item_row: public Item, private Used_tables_and_const_cache
+/**
+  Row items used for comparing rows and IN operations on rows:
+
+  @verbatim
+  (a, b, c) > (10, 10, 30)
+  (a, b, c) = (select c, d, e, from t1 where x=12)
+  (a, b, c) IN ((1,2,2), (3,4,5), (6,7,8)
+  (a, b, c) IN (select c, d, e, from t1)
+  @endverbatim
+*/
+
+class Item_row: public Item,
+                private Item_args,
+                private Used_tables_and_const_cache
 {
-  Item **items;
   table_map not_null_tables_cache;
-  uint arg_count;
   bool with_null;
 public:
-  Item_row(List<Item> &);
+  Item_row(List<Item> &list)
+   :Item_args(list), not_null_tables_cache(0), with_null(0)
+  { }
   Item_row(Item_row *item):
-    Item(),
+    Item_args(item),
     Used_tables_and_const_cache(item),
-    items(item->items),
     not_null_tables_cache(0),
-    arg_count(item->arg_count),
     with_null(0)
   {}
 
@@ -72,18 +83,23 @@ public:
   void update_used_tables()
   {
     used_tables_and_const_cache_init();
-    used_tables_and_const_cache_update_and_join(arg_count, items);
+    used_tables_and_const_cache_update_and_join(arg_count, args);
   }
   table_map not_null_tables() const { return not_null_tables_cache; }
   virtual void print(String *str, enum_query_type query_type);
 
-  bool walk(Item_processor processor, bool walk_subquery, uchar *arg);
+  bool walk(Item_processor processor, bool walk_subquery, uchar *arg)
+  {
+    if (walk_args(processor, walk_subquery, arg))
+      return true;
+    return (this->*processor)(arg);
+  }
   Item *transform(Item_transformer transformer, uchar *arg);
   bool eval_not_null_tables(uchar *opt_arg);
 
   uint cols() { return arg_count; }
-  Item* element_index(uint i) { return items[i]; }
-  Item** addr(uint i) { return items + i; }
+  Item* element_index(uint i) { return args[i]; }
+  Item** addr(uint i) { return args + i; }
   bool check_cols(uint c);
   bool null_inside() { return with_null; };
   void bring_value();