112 lines
4.5 KiB
C++
112 lines
4.5 KiB
C++
/* Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
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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, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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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, version 2.0, 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "my_dbug.h"
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#include "my_inttypes.h"
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#include "storage/heap/heapdef.h"
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/* Read next record with the same key */
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int heap_rnext(HP_INFO *info, uchar *record) {
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uchar *pos;
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HP_SHARE *share = info->s;
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HP_KEYDEF *keyinfo;
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DBUG_TRACE;
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if (info->lastinx < 0) {
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set_my_errno(HA_ERR_WRONG_INDEX);
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return HA_ERR_WRONG_INDEX;
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}
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keyinfo = share->keydef + info->lastinx;
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if (keyinfo->algorithm == HA_KEY_ALG_BTREE) {
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heap_rb_param custom_arg;
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if (info->last_pos) {
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/*
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We enter this branch for non-DELETE queries after heap_rkey()
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or heap_rfirst(). As last key position (info->last_pos) is available,
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we only need to climb the tree using tree_search_next().
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*/
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pos = (uchar *)tree_search_next(&keyinfo->rb_tree, &info->last_pos,
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offsetof(TREE_ELEMENT, left),
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offsetof(TREE_ELEMENT, right));
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} else if (!info->lastkey_len) {
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/*
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We enter this branch only for DELETE queries after heap_rfirst(). E.g.
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DELETE FROM t1 WHERE a<10. As last key position is not available
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(last key is removed by heap_delete()), we must restart search as it
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is done in heap_rfirst().
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It should be safe to handle this situation without this branch. That is
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branch below should find smallest element in a tree as lastkey_len is
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zero. tree_search_edge() is a kind of optimisation here as it should be
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faster than tree_search_key().
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*/
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pos = (uchar *)tree_search_edge(&keyinfo->rb_tree, info->parents,
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&info->last_pos,
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offsetof(TREE_ELEMENT, left));
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} else {
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/*
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We enter this branch only for DELETE queries after heap_rkey(). E.g.
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DELETE FROM t1 WHERE a=10. As last key position is not available
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(last key is removed by heap_delete()), we must restart search as it
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is done in heap_rkey().
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*/
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custom_arg.keyseg = keyinfo->seg;
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custom_arg.key_length = info->lastkey_len;
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custom_arg.search_flag = SEARCH_SAME | SEARCH_FIND;
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pos = (uchar *)tree_search_key(&keyinfo->rb_tree, info->lastkey,
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info->parents, &info->last_pos,
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info->last_find_flag, &custom_arg);
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}
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if (pos) {
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memcpy(&pos, pos + (*keyinfo->get_key_length)(keyinfo, pos),
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sizeof(uchar *));
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info->current_ptr = pos;
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} else {
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set_my_errno(HA_ERR_KEY_NOT_FOUND);
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}
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} else {
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if (info->current_hash_ptr)
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pos =
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hp_search_next(info, keyinfo, info->lastkey, info->current_hash_ptr);
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else {
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if (!info->current_ptr && (info->update & HA_STATE_NEXT_FOUND)) {
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pos = 0; /* Read next after last */
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set_my_errno(HA_ERR_KEY_NOT_FOUND);
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} else if (!info->current_ptr) /* Deleted or first call */
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pos = hp_search(info, keyinfo, info->lastkey, 0);
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else
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pos = hp_search(info, keyinfo, info->lastkey, 1);
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}
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}
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if (!pos) {
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info->update = HA_STATE_NEXT_FOUND; /* For heap_rprev */
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if (my_errno() == HA_ERR_KEY_NOT_FOUND) set_my_errno(HA_ERR_END_OF_FILE);
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return my_errno();
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}
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memcpy(record, pos, (size_t)share->reclength);
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info->update = HA_STATE_AKTIV | HA_STATE_NEXT_FOUND;
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return 0;
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}
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