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80 lines
2.6 KiB
C
80 lines
2.6 KiB
C
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include "myisamdef.h"
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/*
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Read next row with the same key as previous read, but abort if
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the key changes.
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One may have done a write, update or delete of the previous row.
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NOTE! Even if one changes the previous row, the next read is done
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based on the position of the last used key!
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*/
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int mi_rnext_same(MI_INFO *info, byte *buf)
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{
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int error;
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uint inx,flag,not_used;
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MI_KEYDEF *keyinfo;
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DBUG_ENTER("mi_rnext_same");
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if ((int) (inx=info->lastinx) < 0 || info->lastpos == HA_OFFSET_ERROR)
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DBUG_RETURN(my_errno=HA_ERR_WRONG_INDEX);
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keyinfo=info->s->keyinfo+inx;
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flag=SEARCH_BIGGER; /* Read next */
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if (_mi_readinfo(info,F_RDLCK,1))
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DBUG_RETURN(my_errno);
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memcpy(info->lastkey2,info->lastkey,info->last_rkey_length);
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if (info->s->concurrent_insert)
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rw_rdlock(&info->s->key_root_lock[inx]);
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for (;;)
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{
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if ((error=_mi_search_next(info,keyinfo,info->lastkey,
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info->lastkey_length,flag,
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info->s->state.key_root[inx])))
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break;
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if (_mi_key_cmp(keyinfo->seg,info->lastkey2,info->lastkey,
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info->last_rkey_length, SEARCH_FIND, ¬_used))
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{
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error=1;
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my_errno=HA_ERR_END_OF_FILE;
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info->lastpos= HA_OFFSET_ERROR;
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break;
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}
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/* Skip rows that are inserted by other threads since we got a lock */
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if (info->lastpos < info->state->data_file_length)
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break;
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}
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if (info->s->concurrent_insert)
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rw_unlock(&info->s->key_root_lock[inx]);
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/* Don't clear if database-changed */
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info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
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info->update|= HA_STATE_NEXT_FOUND;
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if (error)
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{
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if (my_errno == HA_ERR_KEY_NOT_FOUND)
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my_errno=HA_ERR_END_OF_FILE;
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}
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else if (!(*info->read_record)(info,info->lastpos,buf))
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{
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info->update|= HA_STATE_AKTIV; /* Record is read */
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DBUG_RETURN(0);
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}
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DBUG_RETURN(my_errno);
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} /* mi_rnext */
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