1 files changed, 43 insertions, 8 deletions

diff --git a/sql/item.h b/sql/item.h
index d2303853743..e99aac3a804 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -745,7 +745,11 @@ public:
   virtual bool val_bool_result() { return val_bool(); }
   virtual bool is_null_result() { return is_null(); }
 
-  /* bit map of tables used by item */
+  /* 
+    Bitmap of tables used by item
+    (note: if you need to check dependencies on individual columns, check out
+     class Field_enumerator)
+  */
   virtual table_map used_tables() const { return (table_map) 0L; }
   /*
     Return table map of tables that can't be NULL tables (tables that are
@@ -903,6 +907,8 @@ public:
   virtual bool is_expensive_processor(uchar *arg) { return 0; }
   virtual bool find_item_processor(uchar *arg) { return this == (void *) arg; }
   virtual bool register_field_in_read_map(uchar *arg) { return 0; }
+  virtual bool enumerate_field_refs_processor(uchar *arg) { return 0; }
+  virtual bool mark_as_eliminated_processor(uchar *arg) { return 0; }
   /*
     Check if a partition function is allowed
     SYNOPSIS
@@ -1053,6 +1059,30 @@ public:
 };
 
 
+/*
+  Class to be used to enumerate all field references in an item tree.
+  Suggested usage:
+
+    class My_enumerator : public Field_enumerator 
+    {
+      virtual void visit_field() { ... your actions ...} 
+    }
+
+    My_enumerator enumerator;
+    item->walk(Item::enumerate_field_refs_processor, ...,(uchar*)&enumerator);
+
+  This is similar to Visitor pattern.
+*/
+
+class Field_enumerator
+{
+public:
+  virtual void visit_field(Field *field)= 0;
+  virtual ~Field_enumerator() {};             /* purecov: inspected */
+  Field_enumerator() {}                       /* Remove gcc warning */
+};
+
+
 class sp_head;
 
 
@@ -1522,6 +1552,7 @@ public:
   bool find_item_in_field_list_processor(uchar *arg);
   bool register_field_in_read_map(uchar *arg);
   bool check_partition_func_processor(uchar *int_arg) {return FALSE;}
+  bool enumerate_field_refs_processor(uchar *arg);
   void cleanup();
   bool result_as_longlong()
   {
@@ -2060,9 +2091,9 @@ public:
 class Item_partition_func_safe_string: public Item_string
 {
 public:
-  Item_partition_func_safe_string(const char *name, uint length,
+  Item_partition_func_safe_string(const char *name_arg, uint length,
                                   CHARSET_INFO *cs= NULL):
-    Item_string(name, length, cs)
+    Item_string(name_arg, length, cs)
   {}
 };
 
@@ -2082,8 +2113,8 @@ public:
 class Item_blob :public Item_partition_func_safe_string
 {
 public:
-  Item_blob(const char *name, uint length) :
-    Item_partition_func_safe_string(name, length, &my_charset_bin)
+  Item_blob(const char *name_arg, uint length) :
+    Item_partition_func_safe_string(name_arg, length, &my_charset_bin)
   { max_length= length; }
   enum Type type() const { return TYPE_HOLDER; }
   enum_field_types field_type() const { return MYSQL_TYPE_BLOB; }
@@ -2111,8 +2142,8 @@ class Item_return_int :public Item_int
   enum_field_types int_field_type;
 public:
   Item_return_int(const char *name_arg, uint length,
-		  enum_field_types field_type_arg, longlong value= 0)
-    :Item_int(name_arg, value, length), int_field_type(field_type_arg)
+		  enum_field_types field_type_arg, longlong value_arg= 0)
+    :Item_int(name_arg, value_arg, length), int_field_type(field_type_arg)
   {
     unsigned_flag=1;
   }
@@ -2267,6 +2298,10 @@ public:
     if (!depended_from) 
       (*ref)->update_used_tables(); 
   }
+  bool const_item() const 
+  {
+    return (*ref)->const_item();
+  }
   table_map not_null_tables() const { return (*ref)->not_null_tables(); }
   void set_result_field(Field *field)	{ result_field= field; }
   bool is_result_field() { return 1; }
@@ -3034,7 +3069,7 @@ public:
     Item_cache(field_type_arg), value(0) {}
 
   virtual void store(Item *item){ Item_cache::store(item); }
-  void store(Item *item, longlong val_arg);
+  void store_longlong(Item *item, longlong val_arg);
   double val_real();
   longlong val_int();
   String* val_str(String *str);