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91 lines
2.3 KiB
C
91 lines
2.3 KiB
C
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/******************************************************
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Lock queue iterator. Can iterate over table and record
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lock queues.
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(c) 2007 Innobase Oy
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Created July 16, 2007 Vasil Dimov
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*******************************************************/
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#define LOCK_MODULE_IMPLEMENTATION
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#include "univ.i"
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#include "lock0iter.h"
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#include "lock0lock.h"
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#include "lock0priv.h"
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#include "ut0dbg.h"
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#include "ut0lst.h"
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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
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lock_queue_iterator_reset(
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/*======================*/
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lock_queue_iterator_t* iter, /* out: iterator */
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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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{
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iter->current_lock = lock;
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if (bit_no != ULINT_UNDEFINED) {
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iter->bit_no = bit_no;
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} else {
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switch (lock_get_type(lock)) {
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case LOCK_TABLE:
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iter->bit_no = ULINT_UNDEFINED;
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break;
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case LOCK_REC:
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iter->bit_no = lock_rec_find_set_bit(lock);
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ut_a(iter->bit_no != ULINT_UNDEFINED);
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break;
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default:
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ut_error;
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}
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}
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}
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/***********************************************************************
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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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lock_t*
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lock_queue_iterator_get_prev(
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/*=========================*/
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/* out: previous lock or NULL */
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lock_queue_iterator_t* iter) /* in/out: iterator */
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{
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lock_t* prev_lock;
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switch (lock_get_type(iter->current_lock)) {
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case LOCK_REC:
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prev_lock = lock_rec_get_prev(
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iter->current_lock, iter->bit_no);
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break;
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case LOCK_TABLE:
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prev_lock = UT_LIST_GET_PREV(
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un_member.tab_lock.locks, iter->current_lock);
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break;
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default:
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ut_error;
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}
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if (prev_lock != NULL) {
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iter->current_lock = prev_lock;
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}
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return(prev_lock);
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}
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