Method fetchAbsolute

src/jrd/recsrc/Cursor.cpp:304–366

}

bool Cursor::fetchAbsolute(thread_db* tdbb, SINT64 offset) const
{
	if (!m_rse->isScrollable())
	{
		// error: invalid fetch direction
		status_exception::raise(Arg::Gds(isc_invalid_fetch_option) << Arg::Str("ABSOLUTE"));
	}

	if (!validate(tdbb))
		return false;

	const auto request = tdbb->getRequest();
	Impure* const impure = request->getImpure<Impure>(m_impure);

	if (!impure->irsb_active)
	{
		// error: invalid cursor state
		status_exception::raise(Arg::Gds(isc_cursor_not_open));
	}

	if (!offset)
	{
		impure->irsb_state = BOS;
		return false;
	}

	const auto buffer = static_cast<const BufferedStream*>(m_root);
	const auto count = buffer->getCount(tdbb);
	const SINT64 position = (offset > 0) ? offset - 1 : count + offset;

	if (position < 0)
	{
		impure->irsb_state = BOS;
		return false;
	}
	else if (position >= (SINT64) count)
	{
		impure->irsb_state = EOS;
		return false;
	}

	ProfilerSelectStopWatcher profilerSelectStopWatcher(tdbb, this,
		ProfilerManager::RecordSourceStopWatcher::Event::GET_RECORD);

	impure->irsb_position = position;
	buffer->locate(tdbb, impure->irsb_position);

	if (!buffer->getRecord(tdbb))
	{
		fb_assert(false); // this should not happen
		impure->irsb_state = (offset > 0) ? EOS : BOS;
		return false;
	}

	if (m_updateCounters)
	{
		request->req_records_selected++;
		request->req_records_affected.bumpFetched();