~drizzle-trunk/drizzle/development

/* Copyright (C) 2000-2006 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 */

/*

  OLAP implementation by Sinisa Milivojevic <sinisa@mysql.com>

  Inspired by code submitted by Srilakshmi <lakshmi@gdit.iiit.net>

  The ROLLUP code in this file has to be complitely rewritten as it's

  not good enough to satisfy the goals of MySQL.

  In 4.1 we will replace this with a working, superior implementation

  of ROLLUP.

*/

#ifdef DISABLED_UNTIL_REWRITTEN_IN_4_1

#include <drizzled/server_includes.h>

#include <drizzled/sql_select.h>

/****************************************************************************

  Functions that recursively actually creates new SELECT's

  Returns 0 if OK, 1 if error, -1 if error already printed to client

****************************************************************************/

static int make_new_olap_select(LEX *lex, SELECT_LEX *select_lex, List<Item> new_fields)

{

  THD	*thd=current_thd;

  Item *item, *new_item;

  Item_null *constant= new Item_null("ALL");

  SELECT_LEX *new_select = (SELECT_LEX *) thd->memdup((char*) select_lex, sizeof(*select_lex));

  if (!new_select)

    return 1;

  lex->last_selects->next=new_select;

  new_select->linkage=OLAP_TYPE;

  new_select->olap=NON_EXISTING_ONE;

  new_select->group_list.elements=0;

  new_select->group_list.first=(uchar *)0;

  new_select->group_list.next=(uchar **)&new_select->group_list.first;

  List<Item> privlist;

  List_iterator<Item> list_it(select_lex->item_list);

  List_iterator<Item> new_it(new_fields);

  while ((item=list_it++))

  {

    bool not_found= true;

    if (item->type()==Item::FIELD_ITEM)

    {

      Item_field *iif = (Item_field *)item;

      new_it.rewind();

      while ((new_item=new_it++))

      {

	if (new_item->type()==Item::FIELD_ITEM && 

	    !strcmp(((Item_field*)new_item)->table_name,iif->table_name) &&

	    !strcmp(((Item_field*)new_item)->field_name,iif->field_name))

	{

	  not_found= 0;

	  ((Item_field*)new_item)->db_name=iif->db_name;

	  Item_field *new_one=new Item_field(&select_lex->context,

                                             iif->db_name, iif->table_name, iif->field_name);

	  privlist.push_back(new_one);

	  if (add_to_list(new_select->group_list,new_one,1))

	    return 1;

	  break;

	}

      }

    }

    if (not_found)

    {

      if (item->type() == Item::FIELD_ITEM)

	privlist.push_back(constant);

      else

	privlist.push_back((Item*)thd->memdup((char *)item,item->size_of()));

    }

  }

  new_select->item_list=privlist;

  lex->last_selects = new_select;

  return 0;

}

/****************************************************************************

  Functions that recursively creates combinations of queries for OLAP

  Returns 0 if OK, 1 if error, -1 if error already printed to client

****************************************************************************/

static int  olap_combos(List<Item> old_fields, List<Item> new_fields, Item *item, LEX *lex, 

			      SELECT_LEX *select_lex, int position, int selection, int num_fields, 

			      int num_new_fields)

{

  int sl_return = 0;

  if (position == num_new_fields)

  {

    if (item)

      new_fields.push_front(item);

    sl_return = make_new_olap_select(lex, select_lex, new_fields);

  }

  else

  {

    if (item)

      new_fields.push_front(item);

    while ((num_fields - num_new_fields >= selection - position) && !sl_return)

    {

      item = old_fields.pop();

      sl_return = olap_combos(old_fields, new_fields, item, lex, select_lex, position+1, ++selection, num_fields, num_new_fields);

    }

  }

  return sl_return;

}

/****************************************************************************

  Top level function for converting OLAP clauses to multiple selects

  This is also a place where clauses treatment depends on OLAP type 

  Returns 0 if OK, 1 if error, -1 if error already printed to client

****************************************************************************/

int handle_olaps(LEX *lex, SELECT_LEX *select_lex)

{

  List<Item> item_list_copy, new_item_list;

  item_list_copy.empty();

  new_item_list.empty();

  int count=select_lex->group_list.elements;

  int sl_return=0;

  lex->last_selects=select_lex;

  for (ORDER *order=(ORDER *)select_lex->group_list.first ; order ; order=order->next)

    item_list_copy.push_back(*(order->item));

  List<Item>	all_fields(select_lex->item_list);

  if (setup_tables(lex->thd, &select_lex->context, &select_lex->top_join_list,

                   (TableList *)select_lex->table_list.first

                   &select_lex->leaf_tables, false) ||

      setup_fields(lex->thd, 0, select_lex->item_list, MARK_COLUMNS_READ,

                   &all_fields,1) ||

      setup_fields(lex->thd, 0, item_list_copy, MARK_COLUMNS_READ,

                   &all_fields, 1))

    return -1;

  if (select_lex->olap == CUBE_TYPE)

  {

    for ( int i=count-1; i>=0 && !sl_return; i--)

      sl_return=olap_combos(item_list_copy, new_item_list, (Item *)0, lex, select_lex, 0, 0, count, i);

  }

  else if (select_lex->olap == ROLLUP_TYPE)

  {

    for ( int i=count-1; i>=0 && !sl_return; i--)

    {

      Item *item;

      item_list_copy.pop();

      List_iterator<Item> it(item_list_copy);

      new_item_list.empty();

      while ((item = it++))

	new_item_list.push_front(item);

      sl_return=make_new_olap_select(lex, select_lex, new_item_list);

    }

  }

  else

    sl_return=1; // impossible

  return sl_return;

}

#endif /* DISABLED_UNTIL_REWRITTEN_IN_4_1 */