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/******************************************************
Lock queue iterator type and function prototypes.
(c) 2007 Innobase Oy
Created July 16, 2007 Vasil Dimov
*******************************************************/
#ifndef lock0iter_h
#define lock0iter_h
#include "univ.i"
#include "lock0types.h"
typedef struct lock_queue_iterator_struct {
lock_t* current_lock;
/* In case this is a record lock queue (not table lock queue)
then bit_no is the record number within the heap in which the
record is stored. */
ulint bit_no;
} lock_queue_iterator_t;
/***********************************************************************
Initialize lock queue iterator so that it starts to iterate from
"lock". bit_no specifies the record number within the heap where the
record is stored. It can be undefined (ULINT_UNDEFINED) in two cases:
1. If the lock is a table lock, thus we have a table lock queue;
2. If the lock is a record lock and it is a wait lock. In this case
bit_no is calculated in this function by using
lock_rec_find_set_bit(). There is exactly one bit set in the bitmap
of a wait lock. */
void
lock_queue_iterator_reset(
/*======================*/
lock_queue_iterator_t* iter, /* out: iterator */
lock_t* lock, /* in: lock to start from */
ulint bit_no);/* in: record number in the
heap */
/***********************************************************************
Gets the previous lock in the lock queue, returns NULL if there are no
more locks (i.e. the current lock is the first one). The iterator is
receded (if not-NULL is returned). */
lock_t*
lock_queue_iterator_get_prev(
/*=========================*/
/* out: previous lock or NULL */
lock_queue_iterator_t* iter); /* in/out: iterator */
#endif /* lock0iter_h */
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