Method enqueue

src/lock/lock.cpp:452–602

SRQ_PTR LockManager::enqueue(thread_db* tdbb,
							 CheckStatusWrapper* statusVector,
							 SRQ_PTR prior_request,
							 const USHORT series,
							 const UCHAR* value,
							 const USHORT length,
							 UCHAR type,
							 lock_ast_t ast_routine,
							 void* ast_argument,
							 LOCK_DATA_T data,
							 SSHORT lck_wait,
							 SRQ_PTR owner_offset)
{
/**************************************
 *
 *	e n q u e u e
 *
 **************************************
 *
 * Functional description
 *	Enque on a lock.  If the lock can't be granted immediately,
 *	return an event count on which to wait.  If the lock can't
 *	be granted because of deadlock, return NULL.
 *
 **************************************/
	LOCK_TRACE(("LM::enqueue (%ld)\n", owner_offset));

	if (!owner_offset)
		return 0;

	LockTableGuard guard(this, FB_FUNCTION, owner_offset);

	own* owner = (own*) SRQ_ABS_PTR(owner_offset);
	if (!owner->own_count)
		return 0;

	ASSERT_ACQUIRED;
	++(m_sharedMemory->getHeader()->lhb_enqs);

#ifdef VALIDATE_LOCK_TABLE
	if ((m_sharedMemory->getHeader()->lhb_enqs % 50) == 0)
		validate_lhb(m_sharedMemory->getHeader());
#endif

	if (prior_request)
		internal_dequeue(prior_request);

	// Allocate or reuse a lock request block

	lrq* request;

	ASSERT_ACQUIRED;
	if (SRQ_EMPTY(m_sharedMemory->getHeader()->lhb_free_requests))
	{
		if (!(request = (lrq*) alloc(sizeof(lrq), statusVector)))
			return 0;

		owner = (own*) SRQ_ABS_PTR(owner_offset);