~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 */

/* Remove a row from a MyISAM table */

#include "myisam_priv.h"

#include <mystrings/m_string.h>

#include <drizzled/util/test.h>

static int d_search(MI_INFO *info,MI_KEYDEF *keyinfo,uint32_t comp_flag,

                    unsigned char *key,uint32_t key_length,my_off_t page,unsigned char *anc_buff);

static int del(MI_INFO *info,MI_KEYDEF *keyinfo,unsigned char *key,unsigned char *anc_buff,

	       my_off_t leaf_page,unsigned char *leaf_buff,unsigned char *keypos,

	       my_off_t next_block,unsigned char *ret_key);

static int underflow(MI_INFO *info,MI_KEYDEF *keyinfo,unsigned char *anc_buff,

		     my_off_t leaf_page,unsigned char *leaf_buff,unsigned char *keypos);

static uint32_t remove_key(MI_KEYDEF *keyinfo,uint32_t nod_flag,unsigned char *keypos,

		       unsigned char *lastkey,unsigned char *page_end,

		       my_off_t *next_block);

static int _mi_ck_real_delete(register MI_INFO *info,MI_KEYDEF *keyinfo,

			      unsigned char *key, uint32_t key_length, my_off_t *root);

int mi_delete(MI_INFO *info,const unsigned char *record)

{

  uint32_t i;

  unsigned char *old_key;

  int save_errno;

  char lastpos[8];

  MYISAM_SHARE *share=info->s;

	/* Test if record is in datafile */

  if (!(info->update & HA_STATE_AKTIV))

  {

    return(my_errno=HA_ERR_KEY_NOT_FOUND);	/* No database read */

  }

  if (share->options & HA_OPTION_READ_ONLY_DATA)

  {

    return(my_errno=EACCES);

  }

  if (_mi_readinfo(info,F_WRLCK,1))

    return(my_errno);

  if (info->s->calc_checksum)

    info->checksum=(*info->s->calc_checksum)(info,record);

  if ((*share->compare_record)(info,record))

    goto err;				/* Error on read-check */

  if (_mi_mark_file_changed(info))

    goto err;

	/* Remove all keys from the .ISAM file */

  old_key=info->lastkey2;

  for (i=0 ; i < share->base.keys ; i++ )

  {

    if (mi_is_key_active(info->s->state.key_map, i))

    {

      info->s->keyinfo[i].version++;

      {

        if (info->s->keyinfo[i].ck_delete(info,i,old_key,

                _mi_make_key(info,i,old_key,record,info->lastpos)))

          goto err;

      }

      /* The above changed info->lastkey2. Inform mi_rnext_same(). */

      info->update&= ~HA_STATE_RNEXT_SAME;

    }

  }

  if ((*share->delete_record)(info))

    goto err;				/* Remove record from database */

  info->state->checksum-=info->checksum;

  info->update= HA_STATE_CHANGED+HA_STATE_DELETED+HA_STATE_ROW_CHANGED;

  info->state->records--;

  mi_sizestore(lastpos,info->lastpos);

  _mi_writeinfo(info,WRITEINFO_UPDATE_KEYFILE);

  return(0);

err:

  save_errno=my_errno;

  mi_sizestore(lastpos,info->lastpos);

  if (save_errno != HA_ERR_RECORD_CHANGED)

  {

    mi_print_error(info->s, HA_ERR_CRASHED);

    mi_mark_crashed(info);		/* mark table crashed */

  }

  _mi_writeinfo(info,WRITEINFO_UPDATE_KEYFILE);

  info->update|=HA_STATE_WRITTEN;	/* Buffer changed */

  my_errno=save_errno;

  if (save_errno == HA_ERR_KEY_NOT_FOUND)

  {

    mi_print_error(info->s, HA_ERR_CRASHED);

    my_errno=HA_ERR_CRASHED;

  }

  return(my_errno);

} /* mi_delete */

	/* Remove a key from the btree index */

int _mi_ck_delete(register MI_INFO *info, uint32_t keynr, unsigned char *key,

		  uint32_t key_length)

{

  return _mi_ck_real_delete(info, info->s->keyinfo+keynr, key, key_length,

                            &info->s->state.key_root[keynr]);

} /* _mi_ck_delete */

static int _mi_ck_real_delete(register MI_INFO *info, MI_KEYDEF *keyinfo,

			      unsigned char *key, uint32_t key_length, my_off_t *root)

{

  int error;

  uint32_t nod_flag;

  my_off_t old_root;

  unsigned char *root_buff;

  if ((old_root=*root) == HA_OFFSET_ERROR)

  {

    mi_print_error(info->s, HA_ERR_CRASHED);

    return(my_errno=HA_ERR_CRASHED);

  }

  if (!(root_buff= (unsigned char*) malloc(keyinfo->block_length+

				      MI_MAX_KEY_BUFF*2)))

  {

    return(my_errno=ENOMEM);

  }

  if (!_mi_fetch_keypage(info,keyinfo,old_root,DFLT_INIT_HITS,root_buff,0))

  {

    error= -1;

    goto err;

  }

  if ((error=d_search(info,keyinfo, (SEARCH_SAME), key,key_length,old_root,root_buff)) > 0)

  {

    if (error == 2)

    {

      error=_mi_enlarge_root(info,keyinfo,key,root);

    }

    else /* error == 1 */

    {

      if (mi_getint(root_buff) <= (nod_flag=mi_test_if_nod(root_buff))+3)

      {

	error=0;

	if (nod_flag)

	  *root=_mi_kpos(nod_flag,root_buff+2+nod_flag);

	else

	  *root=HA_OFFSET_ERROR;

	if (_mi_dispose(info,keyinfo,old_root,DFLT_INIT_HITS))

	  error= -1;

      }

      else

	error=_mi_write_keypage(info,keyinfo,old_root,

                                DFLT_INIT_HITS,root_buff);

    }

  }

err:

  free(root_buff);

  return(error);

} /* _mi_ck_real_delete */

	/*

	** Remove key below key root

	** Return values:

	** 1 if there are less buffers;  In this case anc_buff is not saved

	** 2 if there are more buffers

	** -1 on errors

	*/

static int d_search(register MI_INFO *info, register MI_KEYDEF *keyinfo,

                    uint32_t comp_flag, unsigned char *key, uint32_t key_length,

                    my_off_t page, unsigned char *anc_buff)

{

  int flag,ret_value,save_flag;

  uint32_t length,nod_flag,search_key_length;

  bool last_key;

  unsigned char *leaf_buff,*keypos;

  my_off_t leaf_page= 0, next_block;

  unsigned char lastkey[MI_MAX_KEY_BUFF];

  search_key_length= (comp_flag & SEARCH_FIND) ? key_length : USE_WHOLE_KEY;

  flag=(*keyinfo->bin_search)(info,keyinfo,anc_buff,key, search_key_length,

                              comp_flag, &keypos, lastkey, &last_key);

  if (flag == MI_FOUND_WRONG_KEY)

  {

    return(-1);

  }

  nod_flag=mi_test_if_nod(anc_buff);

  leaf_buff= 0;

  if (nod_flag)

  {

    leaf_page=_mi_kpos(nod_flag,keypos);

    if (!(leaf_buff= (unsigned char*) malloc(keyinfo->block_length+

					MI_MAX_KEY_BUFF*2)))

    {

      my_errno=ENOMEM;

      return(-1);

    }

    if (!_mi_fetch_keypage(info,keyinfo,leaf_page,DFLT_INIT_HITS,leaf_buff,0))

      goto err;

  }

  if (flag != 0)

  {

    if (!nod_flag)

    {

      mi_print_error(info->s, HA_ERR_CRASHED);

      my_errno=HA_ERR_CRASHED;		/* This should newer happend */

      goto err;

    }

    save_flag=0;

    ret_value=d_search(info,keyinfo,comp_flag,key,key_length,

                       leaf_page,leaf_buff);

  }

  else

  {						/* Found key */

    uint32_t tmp;

    length=mi_getint(anc_buff);

    if (!(tmp= remove_key(keyinfo,nod_flag,keypos,lastkey,anc_buff+length,

                          &next_block)))

      goto err;

    length-= tmp;

    mi_putint(anc_buff,length,nod_flag);

    if (!nod_flag)

    {						/* On leaf page */

      if (_mi_write_keypage(info,keyinfo,page,DFLT_INIT_HITS,anc_buff))

      {

	return(-1);

      }

      /* Page will be update later if we return 1 */

      return(test(length <= (info->quick_mode ? MI_MIN_KEYBLOCK_LENGTH :

				  (uint) keyinfo->underflow_block_length)));

    }

    save_flag=1;

    ret_value=del(info,keyinfo,key,anc_buff,leaf_page,leaf_buff,keypos,

		  next_block,lastkey);

  }

  if (ret_value >0)

  {

    save_flag=1;

    if (ret_value == 1)

      ret_value= underflow(info,keyinfo,anc_buff,leaf_page,leaf_buff,keypos);

    else

    {				/* This happens only with packed keys */

      if (!_mi_get_last_key(info,keyinfo,anc_buff,lastkey,keypos,&length))

      {

	goto err;

      }

      ret_value=_mi_insert(info,keyinfo,key,anc_buff,keypos,lastkey,

			   (unsigned char*) 0,(unsigned char*) 0,(my_off_t) 0,(bool) 0);

    }

  }

  if (ret_value == 0 && mi_getint(anc_buff) > keyinfo->block_length)

  {

    save_flag=1;

    ret_value=_mi_split_page(info,keyinfo,key,anc_buff,lastkey,0) | 2;

  }

  if (save_flag && ret_value != 1)

    ret_value|=_mi_write_keypage(info,keyinfo,page,DFLT_INIT_HITS,anc_buff);

  free(leaf_buff);

  return(ret_value);

err:

  free(leaf_buff);

  return (-1);

} /* d_search */

	/* Remove a key that has a page-reference */

static int del(register MI_INFO *info, register MI_KEYDEF *keyinfo, unsigned char *key,

	       unsigned char *anc_buff, my_off_t leaf_page, unsigned char *leaf_buff,

	       unsigned char *keypos,		/* Pos to where deleted key was */

	       my_off_t next_block,

	       unsigned char *ret_key)		/* key before keypos in anc_buff */

{

  int ret_value,length;

  uint32_t a_length,nod_flag,tmp;

  my_off_t next_page;

  unsigned char keybuff[MI_MAX_KEY_BUFF],*endpos,*next_buff,*key_start, *prev_key;

  MYISAM_SHARE *share=info->s;

  MI_KEY_PARAM s_temp;

  endpos=leaf_buff+mi_getint(leaf_buff);

  if (!(key_start=_mi_get_last_key(info,keyinfo,leaf_buff,keybuff,endpos,

				   &tmp)))

    return(-1);

  if ((nod_flag=mi_test_if_nod(leaf_buff)))

  {

    next_page= _mi_kpos(nod_flag,endpos);

    if (!(next_buff= (unsigned char*) malloc(keyinfo->block_length+

					MI_MAX_KEY_BUFF*2)))

      return(-1);

    if (!_mi_fetch_keypage(info,keyinfo,next_page,DFLT_INIT_HITS,next_buff,0))

      ret_value= -1;

    else

    {

      if ((ret_value=del(info,keyinfo,key,anc_buff,next_page,next_buff,

			 keypos,next_block,ret_key)) >0)

      {

	endpos=leaf_buff+mi_getint(leaf_buff);

	if (ret_value == 1)

	{

	  ret_value=underflow(info,keyinfo,leaf_buff,next_page,

			      next_buff,endpos);

	  if (ret_value == 0 && mi_getint(leaf_buff) > keyinfo->block_length)

	  {

	    ret_value=_mi_split_page(info,keyinfo,key,leaf_buff,ret_key,0) | 2;

	  }

	}

	else

	{

	  if (!_mi_get_last_key(info,keyinfo,leaf_buff,keybuff,endpos,

				&tmp))

	    goto err;

	  ret_value=_mi_insert(info,keyinfo,key,leaf_buff,endpos,keybuff,

			       (unsigned char*) 0,(unsigned char*) 0,(my_off_t) 0,0);

	}

      }

      if (_mi_write_keypage(info,keyinfo,leaf_page,DFLT_INIT_HITS,leaf_buff))

	goto err;

    }

    free(next_buff);

    return(ret_value);

  }

	/* Remove last key from leaf page */

  mi_putint(leaf_buff,key_start-leaf_buff,nod_flag);

  if (_mi_write_keypage(info,keyinfo,leaf_page,DFLT_INIT_HITS,leaf_buff))

    goto err;

	/* Place last key in ancestor page on deleted key position */

  a_length=mi_getint(anc_buff);

  endpos=anc_buff+a_length;

  if (keypos != anc_buff+2+share->base.key_reflength &&

      !_mi_get_last_key(info,keyinfo,anc_buff,ret_key,keypos,&tmp))

    goto err;

  prev_key=(keypos == anc_buff+2+share->base.key_reflength ?

	    0 : ret_key);

  length=(*keyinfo->pack_key)(keyinfo,share->base.key_reflength,

			      keypos == endpos ? (unsigned char*) 0 : keypos,

			      prev_key, prev_key,

			      keybuff,&s_temp);

  if (length > 0)

    bmove_upp((unsigned char*) endpos+length,(unsigned char*) endpos,(uint) (endpos-keypos));

  else

    memmove(keypos,keypos-length, (int) (endpos-keypos)+length);

  (*keyinfo->store_key)(keyinfo,keypos,&s_temp);

  /* Save pointer to next leaf */

  if (!(*keyinfo->get_key)(keyinfo,share->base.key_reflength,&keypos,ret_key))

    goto err;

  _mi_kpointer(info,keypos - share->base.key_reflength,next_block);

  mi_putint(anc_buff,a_length+length,share->base.key_reflength);

  return( mi_getint(leaf_buff) <=

	       (info->quick_mode ? MI_MIN_KEYBLOCK_LENGTH :

		(uint) keyinfo->underflow_block_length));

err:

  return(-1);

} /* del */

	/* Balances adjacent pages if underflow occours */

static int underflow(register MI_INFO *info, register MI_KEYDEF *keyinfo,

		     unsigned char *anc_buff,

		     my_off_t leaf_page,/* Ancestor page and underflow page */

		     unsigned char *leaf_buff,

		     unsigned char *keypos)	/* Position to pos after key */

{

  int t_length;

  uint32_t length,anc_length,buff_length,leaf_length,p_length,s_length,nod_flag,

       key_reflength,key_length;

  my_off_t next_page;

  unsigned char anc_key[MI_MAX_KEY_BUFF],leaf_key[MI_MAX_KEY_BUFF],

        *buff,*endpos,*next_keypos,*anc_pos,*half_pos,*temp_pos,*prev_key,

        *after_key;

  MI_KEY_PARAM s_temp;

  MYISAM_SHARE *share=info->s;

  buff=info->buff;

  info->buff_used=1;

  next_keypos=keypos;

  nod_flag=mi_test_if_nod(leaf_buff);

  p_length=nod_flag+2;

  anc_length=mi_getint(anc_buff);

  leaf_length=mi_getint(leaf_buff);

  key_reflength=share->base.key_reflength;

  if (info->s->keyinfo+info->lastinx == keyinfo)

    info->page_changed=1;

  if ((keypos < anc_buff+anc_length && (info->state->records & 1)) ||

      keypos == anc_buff+2+key_reflength)

  {					/* Use page right of anc-page */

    if (keyinfo->flag & HA_BINARY_PACK_KEY)

    {

      if (!(next_keypos=_mi_get_key(info, keyinfo,

				    anc_buff, buff, keypos, &length)))

	goto err;

    }

    else

    {

      /* Got to end of found key */

      buff[0]=buff[1]=0;	/* Avoid length error check if packed key */

      if (!(*keyinfo->get_key)(keyinfo,key_reflength,&next_keypos,

			       buff))

      goto err;

    }

    next_page= _mi_kpos(key_reflength,next_keypos);

    if (!_mi_fetch_keypage(info,keyinfo,next_page,DFLT_INIT_HITS,buff,0))

      goto err;

    buff_length=mi_getint(buff);

    /* find keys to make a big key-page */

    memmove(next_keypos - key_reflength, buff + 2, key_reflength);

    if (!_mi_get_last_key(info,keyinfo,anc_buff,anc_key,next_keypos,&length)

	|| !_mi_get_last_key(info,keyinfo,leaf_buff,leaf_key,

			     leaf_buff+leaf_length,&length))

      goto err;

    /* merge pages and put parting key from anc_buff between */

    prev_key=(leaf_length == p_length ? (unsigned char*) 0 : leaf_key);

    t_length=(*keyinfo->pack_key)(keyinfo,nod_flag,buff+p_length,

				  prev_key, prev_key,

				  anc_key, &s_temp);

    length=buff_length-p_length;

    endpos=buff+length+leaf_length+t_length;

    /* buff will always be larger than before !*/

    bmove_upp((unsigned char*) endpos, (unsigned char*) buff+buff_length,length);

    memcpy(buff, leaf_buff, leaf_length);

    (*keyinfo->store_key)(keyinfo,buff+leaf_length,&s_temp);

    buff_length=(uint) (endpos-buff);

    mi_putint(buff,buff_length,nod_flag);

    /* remove key from anc_buff */

    if (!(s_length=remove_key(keyinfo,key_reflength,keypos,anc_key,

                              anc_buff+anc_length,(my_off_t *) 0)))

      goto err;

    anc_length-=s_length;

    mi_putint(anc_buff,anc_length,key_reflength);

    if (buff_length <= keyinfo->block_length)

    {						/* Keys in one page */

      memcpy(leaf_buff, buff, buff_length);

      if (_mi_dispose(info,keyinfo,next_page,DFLT_INIT_HITS))

       goto err;

    }

    else

    {						/* Page is full */

      endpos=anc_buff+anc_length;

      if (keypos != anc_buff+2+key_reflength &&

	  !_mi_get_last_key(info,keyinfo,anc_buff,anc_key,keypos,&length))

	goto err;

      if (!(half_pos=_mi_find_half_pos(nod_flag, keyinfo, buff, leaf_key,

				       &key_length, &after_key)))

	goto err;

      length=(uint) (half_pos-buff);

      memcpy(leaf_buff, buff, length);

      mi_putint(leaf_buff,length,nod_flag);

      /* Correct new keypointer to leaf_page */

      half_pos=after_key;

      _mi_kpointer(info,leaf_key+key_length,next_page);

      /* Save key in anc_buff */

      prev_key=(keypos == anc_buff+2+key_reflength ? (unsigned char*) 0 : anc_key),

      t_length=(*keyinfo->pack_key)(keyinfo,key_reflength,

				    (keypos == endpos ? (unsigned char*) 0 :

				     keypos),

				    prev_key, prev_key,

				    leaf_key, &s_temp);

      if (t_length >= 0)

	bmove_upp((unsigned char*) endpos+t_length,(unsigned char*) endpos,

		  (uint) (endpos-keypos));

      else

	memmove(keypos,keypos-t_length,(uint) (endpos-keypos)+t_length);

      (*keyinfo->store_key)(keyinfo,keypos,&s_temp);

      mi_putint(anc_buff,(anc_length+=t_length),key_reflength);

	/* Store key first in new page */

      if (nod_flag)

	memmove(buff + 2, half_pos - nod_flag, nod_flag);

      if (!(*keyinfo->get_key)(keyinfo,nod_flag,&half_pos,leaf_key))

	goto err;

      t_length=(int) (*keyinfo->pack_key)(keyinfo, nod_flag, (unsigned char*) 0,

					  (unsigned char*) 0, (unsigned char *) 0,

					  leaf_key, &s_temp);

      /* t_length will always be > 0 for a new page !*/

      length=(uint) ((buff+mi_getint(buff))-half_pos);

      memmove(buff + p_length + t_length, half_pos, length);

      (*keyinfo->store_key)(keyinfo,buff+p_length,&s_temp);

      mi_putint(buff,length+t_length+p_length,nod_flag);

      if (_mi_write_keypage(info,keyinfo,next_page,DFLT_INIT_HITS,buff))

	goto err;

    }

    if (_mi_write_keypage(info,keyinfo,leaf_page,DFLT_INIT_HITS,leaf_buff))

      goto err;

    return(anc_length <= ((info->quick_mode ? MI_MIN_BLOCK_LENGTH :

				(uint) keyinfo->underflow_block_length)));

  }

  keypos=_mi_get_last_key(info,keyinfo,anc_buff,anc_key,keypos,&length);

  if (!keypos)

    goto err;

  next_page= _mi_kpos(key_reflength,keypos);

  if (!_mi_fetch_keypage(info,keyinfo,next_page,DFLT_INIT_HITS,buff,0))

      goto err;

  buff_length=mi_getint(buff);

  endpos=buff+buff_length;

  /* find keys to make a big key-page */

  memmove(next_keypos - key_reflength, leaf_buff+2, key_reflength);

  next_keypos=keypos;

  if (!(*keyinfo->get_key)(keyinfo,key_reflength,&next_keypos,

			   anc_key))

    goto err;

  if (!_mi_get_last_key(info,keyinfo,buff,leaf_key,endpos,&length))

    goto err;

  /* merge pages and put parting key from anc_buff between */

  prev_key=(leaf_length == p_length ? (unsigned char*) 0 : leaf_key);

  t_length=(*keyinfo->pack_key)(keyinfo,nod_flag,

				(leaf_length == p_length ?

                                 (unsigned char*) 0 : leaf_buff+p_length),

				prev_key, prev_key,

				anc_key, &s_temp);

  if (t_length >= 0)

    memmove(endpos+t_length,leaf_buff+p_length, leaf_length-p_length);

  else						/* We gained space */

    memmove(endpos, leaf_buff+((int) p_length-t_length),

            leaf_length - p_length + t_length);

  (*keyinfo->store_key)(keyinfo,endpos,&s_temp);

  buff_length=buff_length+leaf_length-p_length+t_length;

  mi_putint(buff,buff_length,nod_flag);

  /* remove key from anc_buff */

  if (!(s_length= remove_key(keyinfo,key_reflength,keypos,anc_key,

                             anc_buff+anc_length,(my_off_t *) 0)))

    goto err;

  anc_length-=s_length;

  mi_putint(anc_buff,anc_length,key_reflength);

  if (buff_length <= keyinfo->block_length)

  {						/* Keys in one page */

    if (_mi_dispose(info,keyinfo,leaf_page,DFLT_INIT_HITS))

      goto err;

  }

  else

  {						/* Page is full */

    if (keypos == anc_buff+2+key_reflength)

      anc_pos=0;				/* First key */

    else if (!_mi_get_last_key(info,keyinfo,anc_buff,anc_pos=anc_key,keypos,

			       &length))

      goto err;

    endpos=_mi_find_half_pos(nod_flag,keyinfo,buff,leaf_key,

			     &key_length, &half_pos);

    if (!endpos)

      goto err;

    _mi_kpointer(info,leaf_key+key_length,leaf_page);

    /* Save key in anc_buff */

    temp_pos=anc_buff+anc_length;

    t_length=(*keyinfo->pack_key)(keyinfo,key_reflength,

				  keypos == temp_pos ? (unsigned char*) 0

				  : keypos,

				  anc_pos, anc_pos,

				  leaf_key,&s_temp);

    if (t_length > 0)

      bmove_upp((unsigned char*) temp_pos+t_length,(unsigned char*) temp_pos,

		(uint) (temp_pos-keypos));

    else

      memmove(keypos,keypos-t_length,(uint) (temp_pos-keypos)+t_length);

    (*keyinfo->store_key)(keyinfo,keypos,&s_temp);

    mi_putint(anc_buff,(anc_length+=t_length),key_reflength);

    /* Store first key on new page */

    if (nod_flag)

      memmove(leaf_buff+2, half_pos - nod_flag, nod_flag);