Code cleanup

sql/item_windowfunc.h

@@ -545,6 +545,7 @@ class Item_window_func : public Item_func_or_sum
   }
   enum Item::Type type() const { return Item::WINDOW_FUNC_ITEM; }
 
+private:
   /* 
     Window functions are very special functions, so val_() methods have
     special meaning for them:
@@ -584,11 +585,6 @@ class Item_window_func : public Item_func_or_sum
     read_value_from_result_field= true;
   }
 
-  void set_read_value_from_result_field() 
-  {
-    read_value_from_result_field= true;
-  }
-
   double val_real() 
   {
     double res;

sql/sql_select.cc

@@ -25898,7 +25898,7 @@ AGGR_OP::end_send()
 
   // Update ref array
   join_tab->join->set_items_ref_array(*join_tab->ref_array);
-  join->process_window_functions(&join->fields_list); // location #2
+  join->process_window_functions(&join->select_lex->window_funcs);
   table->reginfo.lock_type= TL_UNLOCK;
 
   bool in_first_read= true;

sql/sql_select.h

@@ -1494,7 +1494,7 @@ class JOIN :public Sql_alloc
   int init_execution();
   void exec();
 
-  bool process_window_functions(List<Item> *curr_fields_list);
+  bool process_window_functions(List<Item_window_func> *window_funcs);
 
   void exec_inner();
   bool prepare_result(List<Item> **columns_list);

sql/sql_window.cc

@@ -1579,17 +1579,13 @@ bool compute_two_pass_window_functions(Item_window_func *item_win,
     true  Error
 */
 
-bool JOIN::process_window_functions(List<Item> *curr_fields_list)
+bool JOIN::process_window_functions(List<Item_window_func> *window_funcs)
 {
-  List_iterator_fast<Item> it(*curr_fields_list);
-  Item *item;
+  List_iterator_fast<Item_window_func> it(*window_funcs);
+  Item_window_func *item_win;
 
+  while ((item_win= it++))
   {
-    while ((item= it++))
-    {
-      if (item->type() == Item::WINDOW_FUNC_ITEM)
-      {
-        Item_window_func *item_win = (Item_window_func *) item;
     item_win->set_phase_to_computation();
     Window_spec *spec = item_win->window_spec;
     /*
@@ -1606,6 +1602,7 @@ bool JOIN::process_window_functions(List<Item> *curr_fields_list)
        join_tab[top_join_tab_count].table is the temp. table where join
        output was stored.
     */
+    // CAUTION: The sorting criteria list is not yet connected
     add_sorting_to_table(&join_tab[top_join_tab_count],
                          spec->partition_list->first);
     join_tab[top_join_tab_count].used_for_window_func= true;
@@ -1674,8 +1671,6 @@ bool JOIN::process_window_functions(List<Item> *curr_fields_list)
     if (is_error)
       return true;
   }
-    }
-  }
   return false;
 }