diff options
Diffstat (limited to 'sql/item_func.cc')
| -rw-r--r-- | sql/item_func.cc | 64 |
1 files changed, 56 insertions, 8 deletions
diff --git a/sql/item_func.cc b/sql/item_func.cc index 579e7f88ee6..63a2279bb0d 100644 --- a/sql/item_func.cc +++ b/sql/item_func.cc @@ -234,22 +234,21 @@ void Item_func::traverse_cond(Cond_traverser traverser, } - /* Transform an Item_func object with a transformer callback function SYNOPSIS transform() - transformer the transformer callback function to be applied to the nodes - of the tree of the object - argument parameter to be passed to the transformer + transformer the transformer callback function to be applied to the nodes + of the tree of the object + argument parameter to be passed to the transformer DESCRIPTION - The function recursively applies the transform method with the - same transformer to each argument the function. - If the call of the method for a member item returns a new item + The function recursively applies the transform method to each + argument of the Item_func node. + If the call of the method for an argument item returns a new item the old item is substituted for a new one. - After this the transform method is applied to the root node + After this the transformer is applied to the root node of the Item_func object. RETURN VALUES @@ -283,6 +282,55 @@ Item *Item_func::transform(Item_transformer transformer, byte *argument) } +/* + Compile Item_func object with a processor and a transformer callback functions + + SYNOPSIS + compile() + analyzer the analyzer callback function to be applied to the nodes + of the tree of the object + arg_p in/out parameter to be passed to the processor + transformer the transformer callback function to be applied to the nodes + of the tree of the object + arg_t parameter to be passed to the transformer + + DESCRIPTION + First the function applies the analyzer to the root node of + the Item_func object. Then if the analizer succeeeds (returns TRUE) + the function recursively applies the compile method to each argument + of the Item_func node. + If the call of the method for an argument item returns a new item + the old item is substituted for a new one. + After this the transformer is applied to the root node + of the Item_func object. + + RETURN VALUES + Item returned as the result of transformation of the root node +*/ + +Item *Item_func::compile(Item_analyzer analyzer, byte **arg_p, + Item_transformer transformer, byte *arg_t) +{ + if (!(this->*analyzer)(arg_p)) + return 0; + if (arg_count) + { + Item **arg,**arg_end; + for (arg= args, arg_end= args+arg_count; arg != arg_end; arg++) + { + /* + The same parameter value of arg_p must be passed + to analyze any argument of the condition formula. + */ + byte *arg_v= *arg_p; + Item *new_item= (*arg)->compile(analyzer, &arg_v, transformer, arg_t); + if (new_item && *arg != new_item) + current_thd->change_item_tree(arg, new_item); + } + } + return (this->*transformer)(arg_t); +} + /* See comments in Item_cmp_func::split_sum_func() */ void Item_func::split_sum_func(THD *thd, Item **ref_pointer_array, |