1 files changed, 42 insertions, 0 deletions
diff --git a/sql/item.h b/sql/item.h
index c562e30d23d..ab9c93e207d 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -326,6 +326,48 @@ struct Name_resolution_context: Sql_alloc
 };
 
 
+/*
+  Store and restore the current state of a name resolution context.
+*/
+
+class Name_resolution_context_state
+{
+private:
+  TABLE_LIST *save_table_list;
+  TABLE_LIST *save_first_name_resolution_table;
+  TABLE_LIST *save_next_name_resolution_table;
+  bool        save_resolve_in_select_list;
+
+public:
+  TABLE_LIST *save_next_local;
+
+public:
+  /* Save the state of a name resolution context. */
+  void save_state(Name_resolution_context *context, TABLE_LIST *table_list)
+  {
+    save_table_list=                  context->table_list;
+    save_first_name_resolution_table= context->first_name_resolution_table;
+    save_next_name_resolution_table=  (context->first_name_resolution_table) ?
+                                      context->first_name_resolution_table->
+                                               next_name_resolution_table :
+                                      NULL;
+    save_resolve_in_select_list=      context->resolve_in_select_list;
+    save_next_local=                  table_list->next_local;
+  }
+
+  /* Restore a name resolution context from saved state. */
+  void restore_state(Name_resolution_context *context, TABLE_LIST *table_list)
+  {
+    table_list->next_local=                save_next_local;
+    context->table_list=                   save_table_list;
+    context->first_name_resolution_table=  save_first_name_resolution_table;
+    if (context->first_name_resolution_table)
+      context->first_name_resolution_table->
+               next_name_resolution_table= save_next_name_resolution_table;
+    context->resolve_in_select_list=       save_resolve_in_select_list;
+  }
+};
+
 /*************************************************************************/
 
 typedef bool (Item::*Item_processor)(byte *arg);