Item tree iterator

fixed dependence of items from reduced subquery
(SCRUM)

sql/item.cc

@@ -85,6 +85,15 @@ Item_ident::Item_ident(THD *thd, Item_ident &item):
   depended_from(item.depended_from)
 {}
 
+bool Item_ident::remove_dependence_processor(byte * arg)
+{
+  DBUG_ENTER("Item_ident::remove_dependence_processor");
+  if (depended_from == (st_select_lex *) arg)
+    depended_from= 0;
+  DBUG_RETURN(1);
+}
+
+
 bool Item::check_cols(uint c)
 {
   if (c != 1)

sql/item.h

@@ -82,6 +82,8 @@ public:
   }
 };
 
+typedef bool (Item::*Item_processor)(byte *arg);
+
 class Item {
   uint loop_id;                         /* Used to find selfrefering loops */
   Item(const Item &);			/* Prevent use of these */
@@ -188,6 +190,13 @@ public:
   bool binary() const
   { return charset()->state & MY_CS_BINSORT ? 1 : 0 ; }
 
+  virtual bool walk(Item_processor processor, byte *arg)
+  {
+    return (this->*processor)(arg);
+  }
+
+  virtual bool remove_dependence_processor(byte * arg) { return 0; }
+  
   // Row emulation
   virtual uint cols() { return 1; }
   virtual Item* el(uint i) { return this; }
@@ -216,6 +225,8 @@ public:
   // Constructor used by Item_field & Item_ref (see Item comment)
   Item_ident(THD *thd, Item_ident &item);
   const char *full_name() const;
+
+  bool remove_dependence_processor(byte * arg);
 };
 
 
@@ -833,6 +844,12 @@ public:
     return Item_field::save_in_field(field, no_conversions);
   }
   table_map used_tables() const { return (table_map)0L; }
+  
+  bool walk(Item_processor processor, byte *args)
+  {
+    return arg->walk(processor, args) ||
+      (this->*processor)(args);
+  }
 };
 
 class Item_insert_value : public Item_field
@@ -850,6 +867,12 @@ public:
     return Item_field::save_in_field(field, no_conversions);
   }
   table_map used_tables() const { return (table_map)0L; }
+
+  bool walk(Item_processor processor, byte *args)
+  {
+    return arg->walk(processor, args) ||
+	    (this->*processor)(args);
+  }
 };
 
 class Item_cache: public Item

sql/item_cmpfunc.cc

@@ -1094,6 +1094,13 @@ void Item_func_case::split_sum_func(Item **ref_pointer_array,
 }
 
 
+bool Item_func_case::walk (Item_processor processor, byte *arg)
+{
+  return first_expr->walk(processor, arg) ||
+    else_expr->walk(processor, arg) ||
+    Item_func::walk(processor, arg);
+}
+
 void Item_func_case::update_used_tables()
 {
   Item_func::update_used_tables();
@@ -1662,6 +1669,16 @@ Item_cond::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
   return 0;
 }
 
+bool Item_cond::walk(Item_processor processor, byte *arg)
+{
+  List_iterator_fast<Item> li(list);
+  Item *item;
+  while ((item= li++))
+    if (item->walk(processor, arg))
+      return 1;
+  return Item_func::walk(processor, arg);
+}
+
 void Item_cond::split_sum_func(Item **ref_pointer_array, List<Item> &fields)
 {
   List_iterator<Item> li(list);

sql/item_cmpfunc.h

@@ -370,6 +370,8 @@ public:
   bool fix_fields(THD *thd, struct st_table_list *tlist, Item **ref);
   void split_sum_func(Item **ref_pointer_array, List<Item> &fields);
   Item *find_item(String *str);
+
+  bool walk(Item_processor processor, byte *args);
 };
 
 
@@ -632,6 +634,11 @@ class Item_func_in :public Item_int_func
   void update_used_tables();
   void split_sum_func(Item **ref_pointer_array, List<Item> &fields);
   bool nulls_in_row();
+  bool walk(Item_processor processor, byte *arg)
+  {
+    return item->walk(processor, arg) ||
+      Item_int_func::walk(processor, arg);
+  }
 };
 
 /* Functions used by where clause */
@@ -790,6 +797,8 @@ public:
   void split_sum_func(Item **ref_pointer_array, List<Item> &fields);
   friend int setup_conds(THD *thd,TABLE_LIST *tables,COND **conds);
   void top_level_item() { abort_on_null=1; }
+
+  bool walk(Item_processor processor, byte *arg);
 };
 
 

sql/item_func.cc

@@ -136,6 +136,19 @@ Item_func::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
   return 0;
 }
 
+bool Item_func::walk (Item_processor processor, byte *argument)
+{
+  if (arg_count)
+  {
+    Item **arg,**arg_end;
+    for (arg= args, arg_end= args+arg_count; arg != arg_end; arg++)
+    {
+      if ((*arg)->walk(processor, argument))
+	return 1;
+    }
+  }
+  return (this->*processor)(argument);
+}
 
 void Item_func::split_sum_func(Item **ref_pointer_array, List<Item> &fields)
 {
@@ -2434,6 +2447,15 @@ bool Item_func_match::fix_fields(THD *thd, TABLE_LIST *tlist, Item **ref)
   return 0;
 }
 
+bool Item_func_match::walk(Item_processor processor, byte *arg)
+{
+  List_iterator_fast<Item> li(fields);
+  Item *item;
+  while ((item= li++))
+    if (item->walk(processor, arg))
+      return 1;
+  return Item_func::walk(processor, arg);
+}
 
 bool Item_func_match::fix_index()
 {

sql/item_func.h

@@ -134,6 +134,8 @@ public:
   Field *tmp_table_field() { return result_field; }
   Field *tmp_table_field(TABLE *t_arg);
   Item *get_tmp_table_item(THD *thd);
+
+  bool walk(Item_processor processor, byte *arg);
 };
 
 
@@ -647,6 +649,11 @@ public:
     const_item_cache&=  item->const_item();
     with_sum_func= with_sum_func || item->with_sum_func;
   }
+  bool walk(Item_processor processor, byte *arg)
+  {
+    return item->walk(processor, arg) ||
+      Item_int_func::walk(processor, arg);
+  }
 };
 
 
@@ -1024,6 +1031,8 @@ public:
 
   bool fix_index();
   void init_search(bool no_order);
+
+  bool walk(Item_processor processor, byte *arg);
 };
 
 

sql/item_row.cc

@@ -118,6 +118,16 @@ bool Item_row::check_cols(uint c)
   return 0;
 }
 
+bool Item_row::walk(Item_processor processor, byte *arg)
+{
+  for (uint i= 0; i < arg_count; i++)
+  {
+    if (items[i]->walk(processor, arg))
+      return 1;
+  }
+  return (this->*processor)(arg);
+}
+
 void Item_row::bring_value()
 {
   for (uint i= 0; i < arg_count; i++)

sql/item_row.h

@@ -69,6 +69,8 @@ public:
   enum Item_result result_type() const { return ROW_RESULT; }
   void update_used_tables();
 
+  bool walk(Item_processor processor, byte *arg);
+
   uint cols() { return arg_count; }
   Item* el(uint i) { return items[i]; }
   Item** addr(uint i) { return items + i; }

sql/item_strfunc.h

@@ -107,6 +107,11 @@ public:
   }
   void split_sum_func(Item **ref_pointer_array, List<Item> &fields);
   const char *func_name() const { return "concat_ws"; }
+  bool walk(Item_processor processor, byte *arg)
+  {
+    return separator->walk(processor, arg) ||
+      Item_str_func::walk(processor, arg);
+  }
 };
 
 class Item_func_reverse :public Item_str_func
@@ -385,6 +390,11 @@ public:
   void fix_length_and_dec();
   void update_used_tables();
   const char *func_name() const { return "elt"; }
+  bool walk(Item_processor processor, byte *arg)
+  {
+    return item->walk(processor, arg) ||
+      Item_str_func::walk(processor, arg);
+  }
 };
 
 
@@ -407,6 +417,12 @@ public:
   void fix_length_and_dec();
   void update_used_tables();
   const char *func_name() const { return "make_set"; }
+
+  bool walk(Item_processor processor, byte *arg)
+  {
+    return item->walk(processor, arg) ||
+      Item_str_func::walk(processor, arg);
+  }
 };
 
 

sql/item_subselect.cc

@@ -193,7 +193,12 @@ Item_singlerow_subselect::select_transformer(JOIN *join)
 		   ER_SELECT_REDUCED, warn_buff);
     }
     substitution= select_lex->item_list.head();
-     
+    /*
+      as far as we moved content to upper leven, field which depend of
+      'upper' select is not really dependent => we remove this dependence
+    */
+    substitution->walk(&Item::remove_dependence_processor,
+		       (byte *) select_lex->outer_select());
     if (select_lex->where || select_lex->having)
     {
       Item *cond;