mariadb/sql/item_row.h

#ifndef ITEM_ROW_INCLUDED
#define ITEM_ROW_INCLUDED

#include "item_composite.h"

/*
   Copyright (c) 2002, 2013, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */

/**
  Row items used for comparing rows and IN operations on rows:

  @verbatim
  (a, b, c) > (10, 10, 30)
  (a, b, c) = (select c, d, e, from t1 where x=12)
  (a, b, c) IN ((1,2,2), (3,4,5), (6,7,8)
  (a, b, c) IN (select c, d, e, from t1)
  @endverbatim
*/


/**
   Item which stores (x,y,...) and ROW(x,y,...).
   Note that this can be recursive: ((x,y),(z,t)) is a ROW of ROWs.
*/
class Item_row: public Item_composite,
                private Used_tables_and_const_cache
{
  table_map not_null_tables_cache;
  /**
    If elements are made only of constants, of which one or more are
    NULL. For example, this item is (1,2,NULL), or ( (1,NULL), (2,3) ).
  */
  bool with_null;
public:
  Item_row(THD *thd, List<Item> &list)
   :Item_composite(thd, list),
    not_null_tables_cache(0), with_null(0)
  { }
  Item_row(THD *thd, Item_row *row)
   :Item_composite(thd, static_cast<Item_args*>(row)),
    Used_tables_and_const_cache(),
    not_null_tables_cache(0), with_null(0)
  { }

  const Type_handler *type_handler() const override { return &type_handler_row; }
  Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src,
                             const Tmp_field_param *param) override
  {
    return NULL; // Check with Vicentiu why it's called for Item_row
  }
  bool is_null() override { return null_value; }
  bool fix_fields(THD *thd, Item **ref) override;
  void fix_after_pullout(st_select_lex *new_parent, Item **ref, bool merge)
    override;
  void cleanup() override;
  void split_sum_func(THD *thd, Ref_ptr_array ref_pointer_array,
                      List<Item> &fields, uint flags) override;
  table_map used_tables() const override { return used_tables_cache; };
  bool const_item() const override { return const_item_cache; };
  void update_used_tables() override
  {
    used_tables_and_const_cache_init();
    used_tables_and_const_cache_update_and_join(arg_count, args);
  }
  table_map not_null_tables() const override { return not_null_tables_cache; }
  void print(String *str, enum_query_type query_type) override;

  bool walk(Item_processor processor, bool walk_subquery, void *arg) override
  {
    if (walk_args(processor, walk_subquery, arg))
      return true;
    return (this->*processor)(arg);
  }
  Item *transform(THD *thd, Item_transformer transformer, uchar *arg) override;
  bool eval_not_null_tables(void *opt_arg) override;
  bool find_not_null_fields(table_map allowed) override;

  uint cols() const override { return arg_count; }
  Item* element_index(uint i) override { return args[i]; }
  Item** addr(uint i) override { return args + i; }
  bool check_cols(uint c) override;
  bool null_inside() override { return with_null; };
  void bring_value() override;

  Item* propagate_equal_fields(THD *thd, const Context &ctx, COND_EQUAL *cond)
    override
  {
    Item_args::propagate_equal_fields(thd, Context_identity(), cond);
    return this;
  }

  bool excl_dep_on_table(table_map tab_map) override
  {
    return Item_args::excl_dep_on_table(tab_map);
  }

  bool excl_dep_on_grouping_fields(st_select_lex *sel) override
  {
    return Item_args::excl_dep_on_grouping_fields(sel);
  }

  bool excl_dep_on_in_subq_left_part(Item_in_subselect *subq_pred) override
  {
    return Item_args::excl_dep_on_in_subq_left_part(subq_pred);
  }

  bool check_vcol_func_processor(void *arg) override {return FALSE; }
  Item *do_get_copy(THD *thd) const override
  { return get_item_copy<Item_row>(thd, this); }
  Item *do_build_clone(THD *thd) const override;
};

#endif /* ITEM_ROW_INCLUDED */