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/* Copyright (c) 2000, 2025, Oracle and/or its affiliates.
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 designed to work 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 either included with
the program or referenced in the documentation.
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 */
#include <sys/types.h>
#include "my_dbug.h"
#include "my_inttypes.h"
#include "storage/myisam/myisamdef.h"
#include "storage/myisam/rt_index.h"
/*
Read next row with the same key as previous read
One may have done a write, update or delete of the previous row.
NOTE! Even if one changes the previous row, the next read is done
based on the position of the last used key!
*/
int mi_rnext(MI_INFO *info, uchar *buf, int inx) {
int error, changed;
uint flag;
int res = 0;
uint update_mask = HA_STATE_NEXT_FOUND;
DBUG_TRACE;
if ((inx = _mi_check_index(info, inx)) < 0) return my_errno();
flag = SEARCH_BIGGER; /* Read next */
if (info->lastpos == HA_OFFSET_ERROR && info->update & HA_STATE_PREV_FOUND)
flag = 0; /* Read first */
if (fast_mi_readinfo(info)) return my_errno();
if (info->s->concurrent_insert)
mysql_rwlock_rdlock(&info->s->key_root_lock[inx]);
changed = _mi_test_if_changed(info);
if (!flag) {
switch (info->s->keyinfo[inx].key_alg) {
case HA_KEY_ALG_RTREE:
error = rtree_get_first(info, inx, info->lastkey_length);
break;
case HA_KEY_ALG_BTREE:
default:
error = _mi_search_first(info, info->s->keyinfo + inx,
info->s->state.key_root[inx]);
break;
}
/*
"search first" failed. This means we have no pivot for
"search next", or in other words MI_INFO::lastkey is
likely uninitialized.
Normally SQL layer would never request "search next" if
"search first" failed. But HANDLER may do anything.
As mi_rnext() without preceding mi_rkey()/mi_rfirst()
equals to mi_rfirst(), we must restore original state
as if failing mi_rfirst() was not called.
*/
if (error) update_mask |= HA_STATE_PREV_FOUND;
} else {
switch (info->s->keyinfo[inx].key_alg) {
case HA_KEY_ALG_RTREE:
/*
Note that rtree doesn't support that the table
may be changed since last call, so we do need
to skip rows inserted by other threads like in btree
*/
error = rtree_get_next(info, inx, info->lastkey_length);
break;
case HA_KEY_ALG_BTREE:
default:
if (!changed)
error = _mi_search_next(info, info->s->keyinfo + inx, info->lastkey,
info->lastkey_length, flag,
info->s->state.key_root[inx]);
else
error = _mi_search(info, info->s->keyinfo + inx, info->lastkey,
USE_WHOLE_KEY, flag, info->s->state.key_root[inx]);
}
}
if (!error) {
while ((info->s->concurrent_insert &&
info->lastpos >= info->state->data_file_length) ||
(info->index_cond_func &&
!(res = mi_check_index_cond(info, inx, buf)))) {
/*
Skip rows that are either inserted by other threads since
we got a lock or do not match pushed index conditions
*/
if ((error = _mi_search_next(info, info->s->keyinfo + inx, info->lastkey,
info->lastkey_length, SEARCH_BIGGER,
info->s->state.key_root[inx])))
break;
}
if (!error && res == 2) {
if (info->s->concurrent_insert)
mysql_rwlock_unlock(&info->s->key_root_lock[inx]);
info->lastpos = HA_OFFSET_ERROR;
set_my_errno(HA_ERR_END_OF_FILE);
return HA_ERR_END_OF_FILE;
}
}
if (info->s->concurrent_insert) {
if (!error) {
while (info->lastpos >= info->state->data_file_length) {
/* Skip rows inserted by other threads since we got a lock */
if ((error =
_mi_search_next(info, info->s->keyinfo + inx, info->lastkey,
info->lastkey_length, SEARCH_BIGGER,
info->s->state.key_root[inx])))
break;
}
}
mysql_rwlock_unlock(&info->s->key_root_lock[inx]);
}
/* Don't clear if database-changed */
info->update &= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
info->update |= update_mask;
if (error) {
if (my_errno() == HA_ERR_KEY_NOT_FOUND) set_my_errno(HA_ERR_END_OF_FILE);
} else if (!buf) {
return info->lastpos == HA_OFFSET_ERROR ? my_errno() : 0;
} else if (!(*info->read_record)(info, info->lastpos, buf)) {
info->update |= HA_STATE_AKTIV; /* Record is read */
return 0;
}
DBUG_PRINT("error", ("Got error: %d, errno: %d", error, my_errno()));
return my_errno();
} /* mi_rnext */
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