memory leacks in PS with subqueries fixed (adddition to fix of BUG#2462)

sql/item.h:
  mechanism to keep reference in cache array for row IN
sql/item_cmpfunc.cc:
  mechanism to keep reference in cache array for row IN
  layout fixed
sql/item_cmpfunc.h:
  mechanism to keep reference in cache array for row IN
sql/item_subselect.cc:
  fixed memory pools swapping
  prevented deleting Item_in_optimizer cache in case of row IN subquery
sql/mysql_priv.h:
  declarations of function moved to be useful in sql_class.h
sql/sql_base.cc:
  keep fields expanded from '*' in statement memory pool
sql/sql_class.cc:
  fixed restoring/backup of memory pool and list of items
sql/sql_class.h:
  memory allocation methods moved to Statement
  memory pool substituting for preparing
sql/sql_lex.cc:
  ref_pointer_array kept in statement memory
sql/sql_lex.h:
  reinitialization of UNIT
sql/sql_prepare.cc:
  memory allocation/swapping fixed
tests/client_test.c:
  layout fixed

1 files changed, 14 insertions, 2 deletions

diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
index 276c374c353..08712f328ca 100644
--- a/sql/item_cmpfunc.cc
+++ b/sql/item_cmpfunc.cc
@@ -445,7 +445,6 @@ bool Item_in_optimizer::fix_left(THD *thd,
 }
 
 
-
 bool Item_in_optimizer::fix_fields(THD *thd, struct st_table_list *tables,
 				   Item ** ref)
 {
@@ -471,6 +470,7 @@ bool Item_in_optimizer::fix_fields(THD *thd, struct st_table_list *tables,
   return 0;
 }
 
+
 longlong Item_in_optimizer::val_int()
 {
   cache->store(args[0]);
@@ -484,26 +484,38 @@ longlong Item_in_optimizer::val_int()
   return tmp;
 }
 
+
+void Item_in_optimizer::keep_top_level_cache()
+{
+  cache->keep_array();
+  save_cache= 1;
+}
+
+
 void Item_in_optimizer::cleanup()
 {
   DBUG_ENTER("Item_in_optimizer::cleanup");
   Item_bool_func::cleanup();
-  cache= 0;
+  if (!save_cache)
+    cache= 0;
   DBUG_VOID_RETURN;
 }
 
+
 bool Item_in_optimizer::is_null()
 {
   cache->store(args[0]);
   return (null_value= (cache->null_value || args[1]->is_null()));
 }
 
+
 longlong Item_func_eq::val_int()
 {
   int value= cmp.compare();
   return value == 0 ? 1 : 0;
 }
 
+
 /* Same as Item_func_eq, but NULL = NULL */
 
 void Item_func_equal::fix_length_and_dec()