Function CmdCloneVehicle

src/vehicle_cmd.cpp:830–1013

* Clone a vehicle. If it is a train, it will clone all the cars too * @param flags type of operation * @param tile tile of the depot where the cloned vehicle is build * @param veh_id the original vehicle's index * @param share_orders shared orders, else copied orders * @return the cost of this operation + the new vehicle ID or an error */

 * @return the cost of this operation + the new vehicle ID or an error
 */
std::tuple<CommandCost, VehicleID> CmdCloneVehicle(DoCommandFlags flags, TileIndex tile, VehicleID veh_id, bool share_orders)
{
	CommandCost total_cost(EXPENSES_NEW_VEHICLES);

	Vehicle *v = Vehicle::GetIfValid(veh_id);
	if (v == nullptr || !v->IsPrimaryVehicle()) return { CMD_ERROR, VehicleID::Invalid() };
	Vehicle *v_front = v;
	Vehicle *w = nullptr;
	Vehicle *w_front = nullptr;
	Vehicle *w_rear = nullptr;

	/*
	 * v_front is the front engine in the original vehicle
	 * v is the car/vehicle of the original vehicle that is currently being copied
	 * w_front is the front engine of the cloned vehicle
	 * w is the car/vehicle currently being cloned
	 * w_rear is the rear end of the cloned train. It's used to add more cars and is only used by trains
	 */

	CommandCost ret = CheckOwnership(v->owner);
	if (ret.Failed()) return { ret, VehicleID::Invalid() };

	/* Crashed trains can only be cloned before cleanup begins. */
	if (v->type == VEH_TRAIN && (!v->IsFrontEngine() || Train::From(v)->crash_anim_pos >= 4400)) return { CommandCost(STR_ERROR_VEHICLE_IS_DESTROYED), VehicleID::Invalid() };

	/* check that we can allocate enough vehicles */
	if (!flags.Test(DoCommandFlag::Execute)) {
		int veh_counter = 0;
		do {
			veh_counter++;
		} while ((v = v->Next()) != nullptr);

		if (!Vehicle::CanAllocateItem(veh_counter)) {
			return { CommandCost(STR_ERROR_TOO_MANY_VEHICLES_IN_GAME), VehicleID::Invalid() };
		}
	}

	v = v_front;

	VehicleID new_veh_id = VehicleID::Invalid();
	do {
		if (v->type == VEH_TRAIN && Train::From(v)->IsRearDualheaded()) {
			/* we build the rear ends of multiheaded trains with the front ones */
			continue;
		}

		/* In case we're building a multi headed vehicle and the maximum number of
		 * vehicles is almost reached (e.g. max trains - 1) not all vehicles would
		 * be cloned. When the non-primary engines were build they were seen as
		 * 'new' vehicles whereas they would immediately be joined with a primary
		 * engine. This caused the vehicle to be not build as 'the limit' had been
		 * reached, resulting in partially build vehicles and such. */
		DoCommandFlags build_flags = flags;
		if (flags.Test(DoCommandFlag::Execute) && !v->IsPrimaryVehicle()) build_flags.Set(DoCommandFlag::AutoReplace);

		CommandCost cost;
		std::tie(cost, new_veh_id, std::ignore, std::ignore, std::ignore) = Command<CMD_BUILD_VEHICLE>::Do(build_flags, tile, v->engine_type, false, INVALID_CARGO, INVALID_CLIENT_ID);