Function evlGetTranCN

src/jrd/SysFunction.cpp:5031–5070

dsc* evlGetTranCN(thread_db* tdbb, const SysFunction* function, const NestValueArray& args,
	impure_value* impure)
{
	fb_assert(args.getCount() == 1);

	Database* dbb = tdbb->getDatabase();
	Request* request = tdbb->getRequest();

	request->req_flags &= ~req_null;
	const dsc* value = EVL_expr(tdbb, request, args[0]);
	if (request->req_flags & req_null)
		return NULL;

	TraNumber traNum = MOV_get_int64(tdbb, value, 0);
	TraNumber traMax = dbb->dbb_next_transaction;

	if ((traNum > traMax) && !(dbb->dbb_flags & DBB_shared))
	{
		WIN window(HEADER_PAGE_NUMBER);
		const Ods::header_page* header = (Ods::header_page*) CCH_FETCH(tdbb, &window, LCK_read, pag_header);
		traMax = Ods::getNT(header);
		CCH_RELEASE(tdbb, &window);
	}

	if (traNum > traMax)
	{
		request->req_flags |= req_null;
		return NULL;
	}

	CommitNumber cn = dbb->dbb_tip_cache->snapshotState(tdbb, traNum);

	dsc result;
	result.makeInt64(0, (SINT64*)&cn);

	EVL_make_value(tdbb, &result, impure);

	request->req_flags &= ~req_null;
	return &impure->vlu_desc;
}


dsc* evlHash(thread_db* tdbb, const SysFunction* function, const NestValueArray& args,