WL#2486 - Natural/using join according to SQL:2003.

Post-review fixes according to Monty's review.


sql/item.h:
  Unite all code that stores and restores the state of a name resolution context
  into a class to represent the state, and methods to save/restore that
  state.
sql/mysql_priv.h:
  Reorder parameters so that length is after the name of a field,
  and database is before table name.
sql/sql_acl.cc:
  Reorder parameters so that length is after the name of a field,
  and database is before table name.
sql/sql_base.cc:
  * Reorder parameters so that length is after the name of a field,
    and database is before table name.
  * Added new method - Field_iterator_table_ref::get_natural_column_ref
    to avoid unnecessary code when it is knwon that no new columns will
    be created when accessing natural join columns.
sql/sql_insert.cc:
  Unite all code that stores and restores the state of a name resolution context
  into a class to represent the state, and methods to save/restore that
  state.
sql/sql_lex.cc:
  Removed obsolete comment.
sql/sql_lex.h:
  Return error from push_contex() if there is no memory.
sql/sql_list.h:
  Extended base_list_iterator, List_iterator, and List_iterator_fast with an
  empty constructor, and init() methods, so that one doesn't have to construct
  a new iterator object every time one needs to iterate over a new list.
sql/sql_parse.cc:
  Moved common functionality from the parser into one function, and renamed
  the function to better reflect what it does.
sql/sql_yacc.yy:
  Moved common functionality from the parser into one function, and renamed
  the function to better reflect what it does.
sql/table.cc:
  * Extended base_list_iterator, List_iterator, and List_iterator_fast with an
    empty constructor, and init() methods, so that one doesn't have to construct
    a new iterator object every time one needs to iterate over a new list.
  * Added new method Field_iterator_table_ref::get_natural_column_ref to be
    used in cases when it is known for sure that no new columns should be
    created.
sql/table.h:
  - column_ref_it no longer allocated for each new list of columns
  - new method get_natural_join_column for faster/simpler access
    to natural join columns.

1 files changed, 42 insertions, 0 deletions

diff --git a/sql/item.h b/sql/item.h
index 4201790e907..78b919502df 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);