hp_clear.c

/* Copyright (c) 2000-2002, 2004-2007 MySQL AB, 2009 Sun Microsystems, Inc.
   Use is subject to license terms.

   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 02110-1301  USA */

/*
  remove all records from database
  Identical as hp_create() and hp_open() but used HP_SHARE* instead of name and
  database remains open.
*/

#include "heapdef.h"

void heap_clear(HP_INFO *info)
{
  hp_clear(info->s);
}

void hp_clear(HP_SHARE *info)
{
  DBUG_ENTER("hp_clear");

  if (info->block.levels)
    (void) hp_free_level(&info->block,info->block.levels,info->block.root,
                        (uchar*) 0);
  info->block.levels=0;
  hp_clear_keys(info);
  info->records= info->deleted= 0;
  info->data_length= 0;
  info->blength=1;
  info->changed=0;
  info->del_link=0;
  DBUG_VOID_RETURN;
}


/*
  Clear all keys.

  SYNOPSIS
    heap_clear_keys()
    info      A pointer to the heap storage engine HP_INFO struct.

  DESCRIPTION
    Delete all trees of all indexes and leave them empty.

  RETURN
    void
*/

void heap_clear_keys(HP_INFO *info)
{
  hp_clear(info->s);
}


/*
  Clear all keys.

  SYNOPSIS
    hp_clear_keys()
    info      A pointer to the heap storage engine HP_SHARE struct.

  DESCRIPTION
    Delete all trees of all indexes and leave them empty.

  RETURN
    void
*/

void hp_clear_keys(HP_SHARE *info)
{
  uint key;
  DBUG_ENTER("hp_clear_keys");

  for (key=0 ; key < info->keys ; key++)
  {
    HP_KEYDEF *keyinfo = info->keydef + key;
    if (keyinfo->algorithm == HA_KEY_ALG_BTREE)
    {
      delete_tree(&keyinfo->rb_tree);
    }
    else
    {
      HP_BLOCK *block= &keyinfo->block;
      if (block->levels)
        (void) hp_free_level(block,block->levels,block->root,(uchar*) 0);
      block->levels=0;
      block->last_allocated=0;
      keyinfo->hash_buckets= 0;
    }
  }
  info->index_length=0;
  DBUG_VOID_RETURN;
}


/*
  Disable all indexes.

  SYNOPSIS
    heap_disable_indexes()
    info      A pointer to the heap storage engine HP_INFO struct.

  DESCRIPTION
    Disable and clear (remove contents of) all indexes.

  RETURN
    0  ok
*/

int heap_disable_indexes(HP_INFO *info)
{
  HP_SHARE *share= info->s;

  if (share->keys)
  {
    hp_clear_keys(share);
    share->currently_disabled_keys= share->keys;
    share->keys= 0;
  }
  return 0;
}


/*
  Enable all indexes

  SYNOPSIS
    heap_enable_indexes()
    info      A pointer to the heap storage engine HP_INFO struct.

  DESCRIPTION
    Enable all indexes. The indexes might have been disabled
    by heap_disable_index() before.
    The function works only if both data and indexes are empty,
    since the heap storage engine cannot repair the indexes.
    To be sure, call handler::delete_all_rows() before.

  RETURN
    0  ok
    HA_ERR_CRASHED data or index is non-empty.
*/

int heap_enable_indexes(HP_INFO *info)
{
  int error= 0;
  HP_SHARE *share= info->s;

  if (share->data_length || share->index_length)
    error= HA_ERR_CRASHED;
  else
    if (share->currently_disabled_keys)
    {
      share->keys= share->currently_disabled_keys;
      share->currently_disabled_keys= 0;
    }
  return error;
}


/*
  Test if indexes are disabled.

  SYNOPSIS
    heap_indexes_are_disabled()
    info      A pointer to the heap storage engine HP_INFO struct.

  DESCRIPTION
    Test if indexes are disabled.

  RETURN
    0  indexes are not disabled
    1  all indexes are disabled
   [2  non-unique indexes are disabled - NOT YET IMPLEMENTED]
*/

int heap_indexes_are_disabled(HP_INFO *info)
{
  HP_SHARE *share= info->s;

  return (! share->keys && share->currently_disabled_keys);
}