storage/myisam/mi_statrec.c

/* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   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, version 2.0, 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 */

	/* Functions to handle fixed-length-records */

#include "myisamdef.h"


int _mi_write_static_record(MI_INFO *info, const uchar *record)
{
  uchar temp[8];				/* max pointer length */
  if (info->s->state.dellink != HA_OFFSET_ERROR &&
      !info->append_insert_at_end)
  {
    my_off_t filepos=info->s->state.dellink;
    info->rec_cache.seek_not_done=1;		/* We have done a seek */
    if (info->s->file_read(info, &temp[0],info->s->base.rec_reflength,
		info->s->state.dellink+1,
		 MYF(MY_NABP)))
      goto err;
    info->s->state.dellink= _mi_rec_pos(info->s,temp);
    info->state->del--;
    info->state->empty-=info->s->base.pack_reclength;
    if (info->s->file_write(info, record, info->s->base.reclength,
		  filepos,
		  MYF(MY_NABP)))
      goto err;
  }
  else
  {
    if (info->state->data_file_length > info->s->base.max_data_file_length-
	info->s->base.pack_reclength)
    {
      my_errno=HA_ERR_RECORD_FILE_FULL;
      return(2);
    }
    if (info->opt_flag & WRITE_CACHE_USED)
    {				/* Cash in use */
      if (my_b_write(&info->rec_cache, record,
		     info->s->base.reclength))
	goto err;
      if (info->s->base.pack_reclength != info->s->base.reclength)
      {
	uint length=info->s->base.pack_reclength - info->s->base.reclength;
	memset(temp, 0, length);
	if (my_b_write(&info->rec_cache, temp,length))
	  goto err;
      }
    }
    else
    {
      info->rec_cache.seek_not_done=1;		/* We have done a seek */
      if (info->s->file_write(info, record, info->s->base.reclength,
		    info->state->data_file_length,
		    info->s->write_flag))
        goto err;
      if (info->s->base.pack_reclength != info->s->base.reclength)
      {
	uint length=info->s->base.pack_reclength - info->s->base.reclength;
	memset(temp, 0, length);
	if (info->s->file_write(info, temp,length,
		      info->state->data_file_length+
		      info->s->base.reclength,
		      info->s->write_flag))
    goto err;
      }
    }
    info->state->data_file_length+=info->s->base.pack_reclength;
    info->s->state.split++;
  }
  return 0;
 err:
  return 1;
}

int _mi_update_static_record(MI_INFO *info, my_off_t pos, const uchar *record)
{
  info->rec_cache.seek_not_done=1;		/* We have done a seek */
  return (info->s->file_write(info,
                              record, info->s->base.reclength,
                              pos,
                              MYF(MY_NABP)) != 0);
}


int _mi_delete_static_record(MI_INFO *info)
{
  uchar temp[9];				/* 1+sizeof(uint32) */

  info->state->del++;
  info->state->empty+=info->s->base.pack_reclength;
  temp[0]= '\0';			/* Mark that record is deleted */
  _mi_dpointer(info,temp+1,info->s->state.dellink);
  info->s->state.dellink = info->lastpos;
  info->rec_cache.seek_not_done=1;
  return (info->s->file_write(info,(uchar*) temp, 1+info->s->rec_reflength,
		    info->lastpos, MYF(MY_NABP)) != 0);
}


int _mi_cmp_static_record(MI_INFO *info, const uchar *old)
{
  DBUG_ENTER("_mi_cmp_static_record");

  if (info->opt_flag & WRITE_CACHE_USED)
  {
    if (flush_io_cache(&info->rec_cache))
    {
      DBUG_RETURN(-1);
    }
    info->rec_cache.seek_not_done=1;		/* We have done a seek */
  }

  if ((info->opt_flag & READ_CHECK_USED))
  {						/* If check isn't disabled  */
    info->rec_cache.seek_not_done=1;		/* We have done a seek */
    if (info->s->file_read(info, info->rec_buff, info->s->base.reclength,
		 info->lastpos,
		 MYF(MY_NABP)))
      DBUG_RETURN(-1);
    if (memcmp(info->rec_buff, old,
	       (uint) info->s->base.reclength))
    {
      DBUG_DUMP("read",old,info->s->base.reclength);
      DBUG_DUMP("disk",info->rec_buff,info->s->base.reclength);
      my_errno=HA_ERR_RECORD_CHANGED;		/* Record have changed */
      DBUG_RETURN(1);
    }
  }
  DBUG_RETURN(0);
}


int _mi_cmp_static_unique(MI_INFO *info, MI_UNIQUEDEF *def,
			  const uchar *record, my_off_t pos)
{
  DBUG_ENTER("_mi_cmp_static_unique");

  info->rec_cache.seek_not_done=1;		/* We have done a seek */
  if (info->s->file_read(info, info->rec_buff, info->s->base.reclength,
	       pos, MYF(MY_NABP)))
    DBUG_RETURN(-1);
  DBUG_RETURN(mi_unique_comp(def, record, info->rec_buff,
			     def->null_are_equal));
}


	/* Read a fixed-length-record */
	/* Returns 0 if Ok. */
	/*	   1 if record is deleted */
	/*	  MY_FILE_ERROR on read-error or locking-error */

int _mi_read_static_record(MI_INFO *info, my_off_t pos,
			   uchar *record)
{
  int error;

  if (pos != HA_OFFSET_ERROR)
  {
    if (info->opt_flag & WRITE_CACHE_USED &&
	info->rec_cache.pos_in_file <= pos &&
	flush_io_cache(&info->rec_cache))
      return(-1);
    info->rec_cache.seek_not_done=1;		/* We have done a seek */

    error=info->s->file_read(info, record, info->s->base.reclength,
		   pos,MYF(MY_NABP)) != 0;
    fast_mi_writeinfo(info);
    if (! error)
    {
      if (!*record)
      {
	my_errno=HA_ERR_RECORD_DELETED;
	return(1);				/* Record is deleted */
      }
      info->update|= HA_STATE_AKTIV;		/* Record is read */
      return(0);
    }
    return(-1);					/* Error on read */
  }
  fast_mi_writeinfo(info);			/* No such record */
  return(-1);
}


int _mi_read_rnd_static_record(MI_INFO *info, uchar *buf,
			       my_off_t filepos,
			       my_bool skip_deleted_blocks)
{
  int locked,error,cache_read;
  uint cache_length;
  MYISAM_SHARE *share=info->s;
  DBUG_ENTER("_mi_read_rnd_static_record");

  cache_read=0;
  cache_length=0;
  if (info->opt_flag & WRITE_CACHE_USED &&
      (info->rec_cache.pos_in_file <= filepos || skip_deleted_blocks) &&
      flush_io_cache(&info->rec_cache))
    DBUG_RETURN(my_errno);
  if (info->opt_flag & READ_CACHE_USED)
  {						/* Cache in use */
    if (filepos == my_b_tell(&info->rec_cache) &&
	(skip_deleted_blocks || !filepos))
    {
      cache_read=1;				/* Read record using cache */
      cache_length=(uint) (info->rec_cache.read_end - info->rec_cache.read_pos);
    }
    else
      info->rec_cache.seek_not_done=1;		/* Filepos is changed */
  }
  locked=0;
  if (info->lock_type == F_UNLCK)
  {
    if (filepos >= info->state->data_file_length)
    {						/* Test if new records */
      if (_mi_readinfo(info,F_RDLCK,0))
	DBUG_RETURN(my_errno);
      locked=1;
    }
    else
    {						/* We don't nead new info */
#ifndef UNSAFE_LOCKING
      if ((! cache_read || share->base.reclength > cache_length) &&
	  share->tot_locks == 0)
      {						/* record not in cache */
	if (my_lock(share->kfile,F_RDLCK,0L,F_TO_EOF,
		    MYF(MY_SEEK_NOT_DONE) | info->lock_wait))
	  DBUG_RETURN(my_errno);
	locked=1;
      }
#else
      info->tmp_lock_type=F_RDLCK;
#endif
    }
  }
  if (filepos >= info->state->data_file_length)
  {
    DBUG_PRINT("test",("filepos: %ld (%ld)  records: %ld  del: %ld",
		       (long) filepos/share->base.reclength, (long) filepos,
		       (long) info->state->records, (long) info->state->del));
    fast_mi_writeinfo(info);
    DBUG_RETURN(my_errno=HA_ERR_END_OF_FILE);
  }
  info->lastpos= filepos;
  info->nextpos= filepos+share->base.pack_reclength;

  if (! cache_read)			/* No cacheing */
  {
    if ((error=_mi_read_static_record(info,filepos,buf)))
    {
      if (error > 0)
	error=my_errno=HA_ERR_RECORD_DELETED;
      else
	error=my_errno;
    }
    DBUG_RETURN(error);
  }

  /*
    Read record with caching. If my_b_read() returns TRUE, less than the
    requested bytes have been read. In this case rec_cache.error is
    either -1 for a read error, or contains the number of bytes copied
    into the buffer.
  */
  error=my_b_read(&info->rec_cache,(uchar*) buf,share->base.reclength);
  if (info->s->base.pack_reclength != info->s->base.reclength && !error)
  {
    char tmp[8];				/* Skill fill bytes */
    error=my_b_read(&info->rec_cache,(uchar*) tmp,
		    info->s->base.pack_reclength - info->s->base.reclength);
  }
  if (locked)
    (void) _mi_writeinfo(info,0);		/* Unlock keyfile */
  if (!error)
  {
    if (!buf[0])
    {						/* Record is removed */
      DBUG_RETURN(my_errno=HA_ERR_RECORD_DELETED);
    }
						/* Found and may be updated */
    info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED;
    DBUG_RETURN(0);
  }
  /* error is TRUE. my_errno should be set if rec_cache.error == -1 */
  if (info->rec_cache.error != -1 || my_errno == 0)
  {
    /*
      If we could not get a full record, we either have a broken record,
      or are at end of file.
    */
    if (info->rec_cache.error == 0)
      my_errno= HA_ERR_END_OF_FILE;
    else
      my_errno= HA_ERR_WRONG_IN_RECORD;
  }
  DBUG_RETURN(my_errno);			/* Something wrong (EOF?) */
}