Function TryReserveRailTrack

src/pbs.cpp:80–137

* Try to reserve a specific track on a tile * @param tile the tile * @param t the track * @param trigger_stations whether to call station randomisation trigger * @return \c true if reservation was successful, i.e. the track was * free and didn't cross any other reserved tracks. */

 *     free and didn't cross any other reserved tracks.
 */
bool TryReserveRailTrack(TileIndex tile, Track t, bool trigger_stations)
{
	assert(HasTrack(TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_RAIL, 0)), t));

	if (_settings_client.gui.show_track_reservation) {
		/* show the reserved rail if needed */
		if (IsBridgeTile(tile)) {
			MarkBridgeDirty(tile);
		} else {
			MarkTileDirtyByTile(tile);
		}
	}

	switch (GetTileType(tile)) {
		case MP_RAILWAY:
			if (IsPlainRail(tile)) return TryReserveTrack(tile, t);
			if (IsRailDepot(tile)) {
				if (!HasDepotReservation(tile)) {
					SetDepotReservation(tile, true);
					MarkTileDirtyByTile(tile); // some GRFs change their appearance when tile is reserved
					return true;
				}
			}
			break;

		case MP_ROAD:
			if (IsLevelCrossing(tile) && !HasCrossingReservation(tile)) {
				SetCrossingReservation(tile, true);
				UpdateLevelCrossing(tile, false);
				return true;
			}
			break;

		case MP_STATION:
			if (HasStationRail(tile) && !HasStationReservation(tile)) {
				SetRailStationReservation(tile, true);
				if (trigger_stations) {
					auto *st = BaseStation::GetByTile(tile);
					TriggerStationRandomisation(st, tile, StationRandomTrigger::PathReservation);
					TriggerStationAnimation(st, tile, StationAnimationTrigger::PathReservation);
				}
				MarkTileDirtyByTile(tile); // some GRFs need redraw after reserving track
				return true;
			}
			break;

		case MP_TUNNELBRIDGE:
			if (GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL && !GetTunnelBridgeReservationTrackBits(tile)) {
				SetTunnelBridgeReservation(tile, true);
				return true;
			}
			break;

		default:
			break;
	}
	return false;
}