diff options
Diffstat (limited to 'sql/item.h')
| -rw-r--r-- | sql/item.h | 27 |
1 files changed, 21 insertions, 6 deletions
diff --git a/sql/item.h b/sql/item.h index 205c72ede9c..d680c9cf4c6 100644 --- a/sql/item.h +++ b/sql/item.h @@ -734,7 +734,7 @@ public: /* Bitmap of tables used by item (note: if you need to check dependencies on individual columns, check out - check_column_usage_processor) + class Field_enumerator) */ virtual table_map used_tables() const { return (table_map) 0L; } /* @@ -892,7 +892,7 @@ public: virtual bool reset_query_id_processor(uchar *query_id_arg) { return 0; } virtual bool is_expensive_processor(uchar *arg) { return 0; } virtual bool register_field_in_read_map(uchar *arg) { return 0; } - virtual bool check_column_usage_processor(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 @@ -1018,14 +1018,29 @@ public: }; -/* Data for Item::check_column_usage_processor */ +/* + 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 see_field(Field *field)= 0; - virtual ~Field_enumerator() {}; /* Shut up compiler warning */ + virtual void visit_field(Field *field)= 0; + virtual ~Field_enumerator() {}; /* purecov: inspected */ }; + class sp_head; @@ -1491,7 +1506,7 @@ 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 check_column_usage_processor(uchar *arg); + bool enumerate_field_refs_processor(uchar *arg); void cleanup(); bool result_as_longlong() { |