Add wrapper to iterate vehicle pool with vehicle type filter

Without needing to dereference vehicle pointers if using tagged pointers

src/engine.cpp

@@ -961,8 +961,8 @@ static CompanyID GetPreviewCompany(Engine *e)
 				c->old_economy[0].performance_history > best_hist) {
 
 			/* Check whether the company uses similar vehicles */
-			for (const Vehicle *v : Vehicle::Iterate()) {
-				if (v->owner != c->index || v->type != e->type || HasBit(v->subtype, GVSF_VIRTUAL)) continue;
+			for (const Vehicle *v : Vehicle::IterateType(e->type)) {
+				if (v->owner != c->index || HasBit(v->subtype, GVSF_VIRTUAL)) continue;
 				if (!v->GetEngine()->CanCarryCargo() || !HasBit(cargomask, v->cargo_type)) continue;
 
 				best_hist = c->old_economy[0].performance_history;

src/group_cmd.cpp

@@ -823,8 +823,8 @@ CommandCost CmdAddSharedVehicleGroup(TileIndex tile, DoCommandFlag flags, uint32
 	if (flags & DC_EXEC) {
 		/* Find the first front engine which belong to the group id_g
 		 * then add all shared vehicles of this front engine to the group id_g */
-		for (const Vehicle *v : Vehicle::Iterate()) {
-			if (v->type == type && v->IsPrimaryVehicle()) {
+		for (const Vehicle *v : Vehicle::IterateType(type)) {
+			if (v->IsPrimaryVehicle()) {
 				if (v->group_id != id_g) continue;
 
 				/* For each shared vehicles add it to the group */

src/infrastructure.cpp

@@ -254,8 +254,8 @@ bool CheckSharingChangePossible(VehicleType type, bool new_value)
 	});
 
 	StringID error_message = STR_NULL;
-	for (Vehicle *v : Vehicle::Iterate()) {
-		if (type != v->type || HasBit(v->subtype, GVSF_VIRTUAL)) continue;
+	for (Vehicle *v : Vehicle::IterateType(type)) {
+		if (HasBit(v->subtype, GVSF_VIRTUAL)) continue;
 		if (v->Previous() != nullptr) continue;
 
 		/* Check vehicle positiion */

src/order_cmd.cpp

@@ -3786,8 +3786,8 @@ CommandCost CmdMassChangeOrder(TileIndex tile, DoCommandFlag flags, uint32_t p1,
 	DestinationID to_dest = GB(p2, 0, 16);
 
 	if (flags & DC_EXEC) {
-		for (Vehicle *v : Vehicle::Iterate()) {
-			if (v->type == vehtype && v->IsPrimaryVehicle() && CheckOwnership(v->owner).Succeeded() && VehicleCargoFilter(v, cargo_filter)) {
+		for (Vehicle *v : Vehicle::IterateType(vehtype)) {
+			if (v->IsPrimaryVehicle() && CheckOwnership(v->owner).Succeeded() && VehicleCargoFilter(v, cargo_filter)) {
 				int index = 0;
 				bool changed = false;
 

src/settings.cpp

@@ -1224,8 +1224,8 @@ static bool CanUpdateServiceInterval(VehicleType type, int32_t &new_value)
 static void UpdateServiceInterval(VehicleType type, int32_t new_value)
 {
 	if (_game_mode != GM_MENU && Company::IsValidID(_current_company)) {
-		for (Vehicle *v : Vehicle::Iterate()) {
-			if (v->owner == _current_company && v->type == type && v->IsPrimaryVehicle() && !v->ServiceIntervalIsCustom()) {
+		for (Vehicle *v : Vehicle::IterateType(type)) {
+			if (v->owner == _current_company && v->IsPrimaryVehicle() && !v->ServiceIntervalIsCustom()) {
 				v->SetServiceInterval(new_value);
 			}
 		}

src/sl/vehicle_sl.cpp

@@ -595,12 +595,12 @@ void FixupTrainLengths()
 {
 	/* Vehicle center was moved from 4 units behind the front to half the length
 	 * behind the front. Move vehicles so they end up on the same spot. */
-	for (Vehicle *v : Vehicle::Iterate()) {
-		if (v->type == VEH_TRAIN && v->IsPrimaryVehicle()) {
+	for (Train *v : Train::Iterate()) {
+		if (v->IsPrimaryVehicle()) {
 			/* The vehicle center is now more to the front depending on vehicle length,
 			 * so we need to move all vehicles forward to cover the difference to the
 			 * old center, otherwise wagon spacing in trains would be broken upon load. */
-			for (Train *u = Train::From(v); u != nullptr; u = u->Next()) {
+			for (Train *u = v; u != nullptr; u = u->Next()) {
 				if (u->track == TRACK_BIT_DEPOT || (u->vehstatus & VS_CRASHED)) continue;
 
 				Train *next = u->Next();
@@ -670,7 +670,7 @@ void FixupTrainLengths()
 			}
 
 			/* Update all cached properties after moving the vehicle chain around. */
-			Train::From(v)->ConsistChanged(CCF_TRACK);
+			v->ConsistChanged(CCF_TRACK);
 		}
 	}
 }

src/sl/waypoint_sl.cpp

@@ -149,9 +149,7 @@ void MoveWaypointsToBaseStations()
 		for (Order *o = ol->GetFirstOrder(); o != nullptr; o = o->next) UpdateWaypointOrder(o);
 	}
 
-	for (Vehicle *v : Vehicle::Iterate()) {
-		if (v->type != VEH_TRAIN) continue;
-
+	for (Vehicle *v : Vehicle::IterateType(VEH_TRAIN)) {
 		UpdateWaypointOrder(&v->current_order);
 	}
 

src/vehicle.cpp

@@ -3032,9 +3032,9 @@ bool CanBuildVehicleInfrastructure(VehicleType type, byte subtype)
 	}
 
 	/* We should be able to build infrastructure when we have the actual vehicle type */
-	for (const Vehicle *v : Vehicle::Iterate()) {
-		if (v->type == VEH_ROAD && GetRoadTramType(RoadVehicle::From(v)->roadtype) != (RoadTramType)subtype) continue;
-		if (v->owner == _local_company && v->type == type) return true;
+	for (const Vehicle *v : Vehicle::IterateType(type)) {
+		if (type == VEH_ROAD && GetRoadTramType(RoadVehicle::From(v)->roadtype) != (RoadTramType)subtype) continue;
+		if (v->owner == _local_company) return true;
 	}
 
 	return false;

src/vehicle_base.h

@@ -1289,6 +1289,30 @@ public:
 
 	uint32_t GetDisplayMaxWeight() const;
 	uint32_t GetDisplayMinPowerToWeight() const;
+
+	struct VehicleTypeFilter {
+		VehicleType vt;
+
+		bool operator() (size_t index)
+		{
+#if OTTD_UPPER_TAGGED_PTR
+			return VehiclePoolOps::GetVehicleType(_vehicle_pool.GetRaw(index)) == this->vt;
+#else
+			return Vehicle::Get(index)->type == this->vt;
+#endif
+		}
+	};
+
+	/**
+	 * Returns an iterable ensemble of all valid vehicles of the given type
+	 * @param vt the VehicleType to filter
+	 * @param from index of the first vehicle to consider
+	 * @return an iterable ensemble of all valid vehicles of the given type
+	 */
+	static Pool::IterateWrapperFiltered<Vehicle, VehicleTypeFilter> IterateType(VehicleType vt, size_t from = 0)
+	{
+		return Pool::IterateWrapperFiltered<Vehicle, VehicleTypeFilter>(from, VehicleTypeFilter{ vt });
+	}
 };
 
 inline bool IsPointInViewportVehicleRedrawArea(const std::vector<Rect> &viewport_redraw_rects, const Point &pt)

src/vehiclelist.cpp

@@ -73,9 +73,8 @@ void BuildDepotVehicleList(VehicleType type, TileIndex tile, VehicleList *engine
 	engines->clear();
 	if (wagons != nullptr && wagons != engines) wagons->clear();
 
-	for (const Vehicle *v : Vehicle::Iterate()) {
+	for (const Vehicle *v : Vehicle::IterateType(type)) {
 		/* General tests for all vehicle types */
-		if (v->type != type) continue;
 		if (v->tile != tile) continue;
 		if (HasBit(v->subtype, GVSF_VIRTUAL)) continue;
 
@@ -156,8 +155,8 @@ bool GenerateVehicleSortList(VehicleList *list, const VehicleListIdentifier &vli
 	};
 
 	auto fill_all_vehicles = [&]() {
-		for (const Vehicle *v : Vehicle::Iterate()) {
-			if (!HasBit(v->subtype, GVSF_VIRTUAL) && v->type == vli.vtype && v->owner == vli.company && v->IsPrimaryVehicle()) {
+		for (const Vehicle *v : Vehicle::IterateType(vli.vtype)) {
+			if (!HasBit(v->subtype, GVSF_VIRTUAL) && v->owner == vli.company && v->IsPrimaryVehicle()) {
 				add_veh(v);
 			}
 		}
@@ -185,8 +184,8 @@ bool GenerateVehicleSortList(VehicleList *list, const VehicleListIdentifier &vli
 
 		case VL_GROUP_LIST:
 			if (vli.index != ALL_GROUP) {
-				for (const Vehicle *v : Vehicle::Iterate()) {
-					if (!HasBit(v->subtype, GVSF_VIRTUAL) && v->type == vli.vtype && v->IsPrimaryVehicle() &&
+				for (const Vehicle *v : Vehicle::IterateType(vli.vtype)) {
+					if (!HasBit(v->subtype, GVSF_VIRTUAL) && v->IsPrimaryVehicle() &&
 							v->owner == vli.company && GroupIsInGroup(v->group_id, vli.index)) {
 						add_veh(v);
 					}