Method undo

src/jrd/Savepoint.cpp:248–359

}

void VerbAction::undo(thread_db* tdbb, jrd_tra* transaction, bool preserveLocks, VerbAction* preserveAction)
{
	// Undo changes recorded for this verb action.
	// After that, clear the verb action and prepare it for later reuse.

	record_param rpb;
	rpb.rpb_relation = vct_relation;
	rpb.rpb_number.setValue(BOF_NUMBER);
	rpb.rpb_record = NULL;
	rpb.getWindow(tdbb).win_flags = 0;
	rpb.rpb_transaction_nr = transaction->tra_number;

	RecordBitmap::Accessor accessor(vct_records);
	if (accessor.getFirst())
	{
		do
		{
			rpb.rpb_number.setValue(accessor.current());

			const bool have_undo = vct_undo && vct_undo->locate(rpb.rpb_number.getValue());

			if (!DPM_get(tdbb, &rpb, LCK_read))
				BUGCHECK(186);	// msg 186 record disappeared

			if ((have_undo || preserveLocks) && !(rpb.rpb_flags & rpb_deleted))
				VIO_data(tdbb, &rpb, transaction->tra_pool);
			else
				CCH_RELEASE(tdbb, &rpb.getWindow(tdbb));

			if (rpb.rpb_transaction_nr != transaction->tra_number)
				BUGCHECK(185);	// msg 185 wrong record version

			if (!have_undo)
			{
				if (preserveLocks && rpb.rpb_b_page)
				{
					// Fetch previous record version and update in place current version with it
					record_param temp = rpb;
					temp.rpb_page = rpb.rpb_b_page;
					temp.rpb_line = rpb.rpb_b_line;
					temp.rpb_record = NULL;

					if (temp.rpb_flags & rpb_delta)
						fb_assert(temp.rpb_prior != NULL);
					else
						fb_assert(temp.rpb_prior == NULL);

					if (!DPM_fetch(tdbb, &temp, LCK_read))
						BUGCHECK(291);		// msg 291 cannot find record back version

					if (!(temp.rpb_flags & rpb_chained) || (temp.rpb_flags & (rpb_blob | rpb_fragment)))
						ERR_bugcheck_msg("invalid back version");

					VIO_data(tdbb, &temp, tdbb->getDefaultPool());

					Record* const save_record = rpb.rpb_record;
					if (rpb.rpb_flags & rpb_deleted)
						rpb.rpb_record = NULL;