_statrec.c
上传用户:romrleung
上传日期:2022-05-23
资源大小:18897k
文件大小:8k
- /* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult 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; either version 2 of the License, or
- (at your option) any later version.
- 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 */
- /* Functions to handle fixed-length-records */
- #include "isamdef.h"
- int _nisam_write_static_record(N_INFO *info, const byte *record)
- {
- uchar temp[4]; /* Not sizeof(long) */
- if (info->s->state.dellink != NI_POS_ERROR)
- {
- ulong filepos=info->s->state.dellink;
- info->rec_cache.seek_not_done=1; /* We have done a seek */
- VOID(my_seek(info->dfile,info->s->state.dellink+1,MY_SEEK_SET,MYF(0)));
- if (my_read(info->dfile,(char*) &temp[0],sizeof(temp), MYF(MY_NABP)))
- goto err;
- info->s->state.dellink=uint4korr(temp);
- if (info->s->state.dellink == (uint32) ~0) /* Fix for 64 bit long */
- info->s->state.dellink=NI_POS_ERROR;
- info->s->state.del--;
- info->s->state.empty-=info->s->base.reclength;
- VOID(my_seek(info->dfile,filepos,MY_SEEK_SET,MYF(0)));
- if (my_write(info->dfile, (char*) record, info->s->base.reclength,
- MYF(MY_NABP)))
- goto err;
- }
- else
- {
- if (info->s->state.data_file_length > info->s->base.max_data_file_length)
- {
- 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, (byte*) record, info->s->base.reclength))
- goto err;
- }
- else
- {
- info->rec_cache.seek_not_done=1; /* We have done a seek */
- VOID(my_seek(info->dfile,info->s->state.data_file_length,
- MY_SEEK_SET,MYF(0)));
- if (my_write(info->dfile,(char*) record,info->s->base.reclength,
- MYF(MY_NABP | MY_WAIT_IF_FULL)))
- goto err;
- }
- info->s->state.data_file_length+=info->s->base.reclength;
- info->s->state.splitt++;
- }
- return 0;
- err:
- return 1;
- }
- int _nisam_update_static_record(N_INFO *info, ulong pos, const byte *record)
- {
- info->rec_cache.seek_not_done=1; /* We have done a seek */
- VOID(my_seek(info->dfile,pos,MY_SEEK_SET,MYF(0)));
- return (my_write(info->dfile,(char*) record,info->s->base.reclength,
- MYF(MY_NABP)) != 0);
- }
- int _nisam_delete_static_record(N_INFO *info)
- {
- uchar temp[5]; /* 1+sizeof(uint32) */
- info->s->state.del++;
- info->s->state.empty+=info->s->base.reclength;
- temp[0]= ' '; /* Mark that record is deleted */
- int4store(temp+1,info->s->state.dellink);
- info->s->state.dellink = info->lastpos;
- info->rec_cache.seek_not_done=1;
- VOID(my_seek(info->dfile,info->lastpos,MY_SEEK_SET,MYF(0)));
- return (my_write(info->dfile,(byte*) temp,(uint) sizeof(temp),
- MYF(MY_NABP)) != 0);
- }
- int _nisam_cmp_static_record(register N_INFO *info, register const byte *old)
- {
- DBUG_ENTER("_nisam_rectest");
- /* We are going to do changes; dont let anybody disturb */
- dont_break(); /* Dont allow SIGHUP or SIGINT */
- 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 */
- VOID(my_seek(info->dfile,info->lastpos,MY_SEEK_SET,MYF(0)));
- if (my_read(info->dfile, (char*) info->rec_buff, info->s->base.reclength,
- MYF(MY_NABP)))
- DBUG_RETURN(-1);
- if (memcmp((byte*) info->rec_buff, (byte*) 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);
- }
- /* Read a fixed-length-record */
- /* Returns 0 if Ok. */
- /* 1 if record is deleted */
- /* MY_FILE_ERROR on read-error or locking-error */
- int _nisam_read_static_record(register N_INFO *info, register ulong pos,
- register byte *record)
- {
- int error;
- if (pos != NI_POS_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=my_pread(info->dfile,(char*) record,info->s->base.reclength,
- pos,MYF(MY_NABP)) != 0;
- if (info->s->r_locks == 0 && info->s->w_locks == 0)
- VOID(_nisam_writeinfo(info,0));
- if (! error)
- {
- if (!*record) return(1); /* Record is deleted */
- info->update|= HA_STATE_AKTIV; /* Record is read */
- my_errno=HA_ERR_RECORD_DELETED;
- return(0);
- }
- return(-1); /* Error on read */
- }
- VOID(_nisam_writeinfo(info,0)); /* No such record */
- return(-1);
- } /* _nisam_read_record */
- int _nisam_read_rnd_static_record(N_INFO *info, byte *buf,
- register ulong filepos,
- int skipp_deleted_blocks)
- {
- int locked,error,cache_read;
- uint cache_length;
- ISAM_SHARE *share=info->s;
- DBUG_ENTER("_nisam_read_rnd_static_record");
- cache_read=0;
- LINT_INIT(cache_length);
- if (info->opt_flag & WRITE_CACHE_USED &&
- (info->rec_cache.pos_in_file <= filepos || skipp_deleted_blocks) &&
- flush_io_cache(&info->rec_cache))
- DBUG_RETURN(-1);
- if (info->opt_flag & READ_CACHE_USED)
- { /* Cash in use */
- if (filepos == my_b_tell(&info->rec_cache) &&
- (skipp_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 */
- }
- #ifndef NO_LOCKING
- locked=0;
- if (info->lock_type == F_UNLCK)
- {
- if (filepos >= share->state.data_file_length)
- { /* Test if new records */
- if (_nisam_readinfo(info,F_RDLCK,0))
- DBUG_RETURN(-1);
- locked=1;
- }
- else
- { /* We don't nead new info */
- #ifndef UNSAFE_LOCKING
- if ((! cache_read || share->base.reclength > cache_length) &&
- share->r_locks == 0 && share->w_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(-1);
- locked=1;
- }
- #else
- info->tmp_lock_type=F_RDLCK;
- #endif
- }
- }
- #endif
- if (filepos >= share->state.data_file_length)
- {
- #ifndef NO_LOCKING
- DBUG_PRINT("test",("filepos: %ld (%ld) records: %ld del: %ld",
- filepos/share->base.reclength,filepos,
- share->state.records, share->state.del));
- VOID(_nisam_writeinfo(info,0));
- #endif
- my_errno=HA_ERR_END_OF_FILE;
- DBUG_RETURN(-1);
- }
- info->lastpos= filepos;
- info->nextpos= filepos+share->base.reclength;
- if (! cache_read) /* No cacheing */
- {
- error=_nisam_read_static_record(info,filepos,buf);
- if (error > 0)
- my_errno=HA_ERR_RECORD_DELETED;
- DBUG_RETURN(error);
- }
- /* Read record with cacheing */
- error=my_b_read(&info->rec_cache,(byte*) buf,share->base.reclength);
- #ifndef NO_LOCKING
- if (locked)
- VOID(_nisam_writeinfo(info,0)); /* Unlock keyfile */
- #endif
- if (!error)
- {
- if (!buf[0])
- { /* Record is removed */
- my_errno=HA_ERR_RECORD_DELETED;
- DBUG_RETURN(1);
- }
- /* Found and may be updated */
- info->update|= HA_STATE_AKTIV | HA_STATE_KEY_CHANGED;
- DBUG_RETURN(0);
- }
- if (info->rec_cache.error != -1 || my_errno == 0)
- my_errno=HA_ERR_WRONG_IN_RECORD;
- DBUG_RETURN(-1); /* Something wrong (EOF?) */
- }