69 lines
2.8 KiB
C
69 lines
2.8 KiB
C
/*****************************************************************************
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Copyright (c) 2007, 2018, Oracle and/or its affiliates. All Rights Reserved.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License, version 2.0, as published by the
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Free Software Foundation.
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This program is also distributed with certain software (including but not
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limited to OpenSSL) that is licensed under separate terms, as designated in a
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particular file or component or in included license documentation. The authors
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of MySQL hereby grant you an additional permission to link the program and
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your derivative works with the separately licensed software that they have
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included with MySQL.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
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for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*****************************************************************************/
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/** @file include/lock0iter.h
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Lock queue iterator type and function prototypes.
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Created July 16, 2007 Vasil Dimov
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*******************************************************/
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#ifndef lock0iter_h
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#define lock0iter_h
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#include "lock0types.h"
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#include "univ.i"
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struct lock_queue_iterator_t {
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const lock_t *current_lock;
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/* In case this is a record lock queue (not table lock queue)
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then bit_no is the record number within the heap in which the
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record is stored. */
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ulint bit_no;
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};
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/** Initialize lock queue iterator so that it starts to iterate from
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"lock". bit_no specifies the record number within the heap where the
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record is stored. It can be undefined (ULINT_UNDEFINED) in two cases:
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1. If the lock is a table lock, thus we have a table lock queue;
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2. If the lock is a record lock and it is a wait lock. In this case
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bit_no is calculated in this function by using
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lock_rec_find_set_bit(). There is exactly one bit set in the bitmap
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of a wait lock. */
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void lock_queue_iterator_reset(
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lock_queue_iterator_t *iter, /*!< out: iterator */
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const lock_t *lock, /*!< in: lock to start from */
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ulint bit_no); /*!< in: record number in the
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heap */
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/** Gets the previous lock in the lock queue, returns NULL if there are no
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more locks (i.e. the current lock is the first one). The iterator is
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receded (if not-NULL is returned).
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@return previous lock or NULL */
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const lock_t *lock_queue_iterator_get_prev(
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lock_queue_iterator_t *iter); /*!< in/out: iterator */
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#endif /* lock0iter_h */
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