Method blocking_ast_gcLock

src/jrd/Relation.cpp:452–503

}

int jrd_rel::blocking_ast_gcLock(void* ast_object)
{
	/****
	SR - gc forbidden, awaiting moment to re-establish SW lock
	SW - gc allowed, usual state
	PW - gc allowed to the one connection only
	****/

	jrd_rel* relation = static_cast<jrd_rel*>(ast_object);

	try
	{
		Lock* lock = relation->rel_gc_lock;
		Database* dbb = lock->lck_dbb;

		AsyncContextHolder tdbb(dbb, FB_FUNCTION, lock);

		fb_assert(!(relation->rel_flags & REL_gc_lockneed));
		if (relation->rel_flags & REL_gc_lockneed) // work already done synchronously ?
			return 0;

		relation->rel_flags |= REL_gc_blocking;
		if (relation->rel_sweep_count)
			return 0;

		if (relation->rel_flags & REL_gc_disabled)
		{
			// someone acquired EX lock

			fb_assert(lock->lck_id);
			fb_assert(lock->lck_physical == LCK_SR);

			LCK_release(tdbb, lock);
			relation->rel_flags &= ~(REL_gc_disabled | REL_gc_blocking);
			relation->rel_flags |= REL_gc_lockneed;
		}
		else
		{
			// someone acquired PW lock

			fb_assert(lock->lck_id);
			fb_assert(lock->lck_physical == LCK_SW);

			relation->rel_flags |= REL_gc_disabled;
			relation->downgradeGCLock(tdbb);
		}
	}
	catch (const Firebird::Exception&)
	{} // no-op

	return 0;
}


/// jrd_rel::GCExclusive