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 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 */

        /* 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(register MI_INFO *info, register 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(register MI_INFO *info, register my_off_t pos,
                           register 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,
                               register 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?) */
}