~drizzle-trunk/drizzle/development

/* Copyright (C) 2000 MySQL AB

   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#include "mysql_priv.h"

/**

  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

  @todo

    think placing 2-3 component items in item (as it done for function

*/

Item_row::Item_row(List<Item> &arg):

  Item(), used_tables_cache(0), const_item_cache(1), with_null(0)

{

  //TODO: think placing 2-3 component items in item (as it done for function)

  if ((arg_count= arg.elements))

    items= (Item**) sql_alloc(sizeof(Item*)*arg_count);

  else

    items= 0;

  List_iterator<Item> li(arg);

  uint i= 0;

  Item *item;

  while ((item= li++))

  {

    items[i]= item;

    i++;    

  }

}

void Item_row::illegal_method_call(const char *method)

{

  DBUG_ENTER("Item_row::illegal_method_call");

  DBUG_PRINT("error", ("!!! %s method was called for row item", method));

  DBUG_ASSERT(0);

  my_error(ER_OPERAND_COLUMNS, MYF(0), 1);

  DBUG_VOID_RETURN;

}

bool Item_row::fix_fields(THD *thd, Item **ref)

{

  DBUG_ASSERT(fixed == 0);

  null_value= 0;

  maybe_null= 0;

  Item **arg, **arg_end;

  for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)

  {

    if ((*arg)->fix_fields(thd, arg))

      return TRUE;

    // we can't assign 'item' before, because fix_fields() can change arg

    Item *item= *arg;

    used_tables_cache |= item->used_tables();

    const_item_cache&= item->const_item() && !with_null;

    if (const_item_cache)

    {

      if (item->cols() > 1)

	with_null|= item->null_inside();

      else

      {

	if (item->is_null())

          with_null|= 1;

      }

    }

    maybe_null|= item->maybe_null;

    with_sum_func= with_sum_func || item->with_sum_func;

  }

  fixed= 1;

  return FALSE;

}

void Item_row::cleanup()

{

  DBUG_ENTER("Item_row::cleanup");

  Item::cleanup();

  /* Reset to the original values */

  used_tables_cache= 0;

  const_item_cache= 1;

  with_null= 0;

  DBUG_VOID_RETURN;

}

void Item_row::split_sum_func(THD *thd, Item **ref_pointer_array,

                              List<Item> &fields)

{

  Item **arg, **arg_end;

  for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)

    (*arg)->split_sum_func2(thd, ref_pointer_array, fields, arg, TRUE);

}

void Item_row::update_used_tables()

{

  used_tables_cache= 0;

  const_item_cache= 1;

  for (uint i= 0; i < arg_count; i++)

  {

    items[i]->update_used_tables();

    used_tables_cache|= items[i]->used_tables();

    const_item_cache&= items[i]->const_item();

  }

}

void Item_row::fix_after_pullout(st_select_lex *new_parent, Item **ref)

{

  used_tables_cache= 0;

  const_item_cache= 1;

  for (uint i= 0; i < arg_count; i++)

  {

    items[i]->fix_after_pullout(new_parent, &items[i]);

    used_tables_cache|= items[i]->used_tables();

    const_item_cache&= items[i]->const_item();

  }

}

bool Item_row::check_cols(uint c)

{

  if (c != arg_count)

  {

    my_error(ER_OPERAND_COLUMNS, MYF(0), c);

    return 1;

  }

  return 0;

}

void Item_row::print(String *str, enum_query_type query_type)

{

  str->append('(');

  for (uint i= 0; i < arg_count; i++)

  {

    if (i)

      str->append(',');

    items[i]->print(str, query_type);

  }

  str->append(')');

}

bool Item_row::walk(Item_processor processor, bool walk_subquery, uchar *arg)

{

  for (uint i= 0; i < arg_count; i++)

  {

    if (items[i]->walk(processor, walk_subquery, arg))

      return 1;

  }

  return (this->*processor)(arg);

}

Item *Item_row::transform(Item_transformer transformer, uchar *arg)

{

  for (uint i= 0; i < arg_count; i++)

  {

    Item *new_item= items[i]->transform(transformer, arg);

    if (!new_item)

      return 0;

    /*

      THD::change_item_tree() should be called only if the tree was

      really transformed, i.e. when a new item has been created.

      Otherwise we'll be allocating a lot of unnecessary memory for

      change records at each execution.

    */

    if (items[i] != new_item)

      current_thd->change_item_tree(&items[i], new_item);

  }

  return (this->*transformer)(arg);

}

void Item_row::bring_value()

{

  for (uint i= 0; i < arg_count; i++)

    items[i]->bring_value();

}