Change: Keep removed depots in the pool for a while. (based on patch …

…by adf, OpenTTD#6328, OpenTTD#7051)

src/build_vehicle_gui.cpp

@@ -1150,6 +1150,9 @@ struct BuildVehicleWindow : Window {
 				break;
 
 			case VEH_SHIP:
+				this->filter.railtypes = this->listview_mode ? INVALID_RAILTYPES : depot->r_types.rail_types;
+				break;
+
 			case VEH_AIRCRAFT:
 				break;
 		}
@@ -1340,14 +1343,17 @@ struct BuildVehicleWindow : Window {
 		EngineID sel_id = INVALID_ENGINE;
 		this->eng_list.clear();
 
-		for (const Engine *e : Engine::IterateType(VEH_SHIP)) {
-			if (!this->show_hidden_engines && e->IsHidden(_local_company)) continue;
-			EngineID eid = e->index;
-			if (!IsEngineBuildable(eid, VEH_SHIP, _local_company)) continue;
-			this->eng_list.push_back(eid);
+		if (this->listview_mode || this->filter.railtypes != RAILTYPES_NONE) {
+			for (const Engine *e : Engine::IterateType(VEH_SHIP)) {
+				if (!this->show_hidden_engines && e->IsHidden(_local_company)) continue;
+				EngineID eid = e->index;
+				if (!IsEngineBuildable(eid, VEH_SHIP, _local_company)) continue;
+				this->eng_list.push_back(eid);
 
-			if (eid == this->sel_engine) sel_id = eid;
+				if (eid == this->sel_engine) sel_id = eid;
+			}
 		}
+
 		this->SelectEngine(sel_id);
 	}
 

src/date_type.h

@@ -33,6 +33,7 @@ static const int MONTHS_IN_YEAR    =  12; ///< months per year
 static const int STATION_RATING_TICKS     = 185; ///< cycle duration for updating station rating
 static const int STATION_ACCEPTANCE_TICKS = 250; ///< cycle duration for updating station acceptance
 static const int STATION_LINKGRAPH_TICKS  = 504; ///< cycle duration for cleaning dead links
+static const int DEPOT_REMOVAL_TICKS      = 250; ///< cycle duration for cleaning demolished depots
 static const int CARGO_AGING_TICKS        = 185; ///< cycle duration for aging cargo
 static const int INDUSTRY_PRODUCE_TICKS   = 256; ///< cycle duration for industry production
 static const int TOWN_GROWTH_TICKS        = 70;  ///< cycle duration for towns trying to grow. (this originates from the size of the town array in TTD

src/depot.cpp

@@ -61,6 +61,23 @@ Depot::~Depot()
 	CloseWindowById(GetWindowClassForVehicleType(this->veh_type),
 			VehicleListIdentifier(VL_DEPOT_LIST,
 			this->veh_type, this->company, this->index).Pack());
+
+	InvalidateWindowData(WC_SELECT_DEPOT, this->veh_type);
+}
+
+/**
+ * Schedule deletion of this depot.
+ *
+ * This method is ought to be called after demolishing last depot part.
+ * The depot will be kept in the pool for a while so it can be
+ * placed again later without messing vehicle orders.
+ *
+ * @see Depot::IsInUse
+ */
+void Depot::Disuse()
+{
+	/* Mark that the depot is demolished and start the countdown. */
+	this->delete_ctr = 8;
 }
 
 /**
@@ -132,7 +149,8 @@ void Depot::AfterAddRemove(TileArea ta, bool adding)
 		this->xy = this->depot_tiles[0];
 		assert(IsDepotTile(this->xy));
 	} else {
-		delete this;
+		assert(this->IsInUse());
+		this->Disuse();
 	}
 
 	InvalidateWindowData(WC_SELECT_DEPOT, veh_type);

src/depot_base.h

@@ -26,11 +26,12 @@ struct Depot : DepotPool::PoolItem<&_depot_pool> {
 	std::string name;
 
 	TileIndex xy;
-	uint16 town_cn;    ///< The N-1th depot for this town (consecutive number)
-	Date build_date;   ///< Date of construction
+	uint16 town_cn;       ///< The N-1th depot for this town (consecutive number)
+	Date build_date;      ///< Date of construction
 
 	CompanyID company;
 	VehicleType veh_type;
+	byte delete_ctr;      ///< Delete counter. If greater than 0 then it is decremented until it reaches 0; the depot is then deleted.
 
 	union {
 		RoadTypes road_types;
@@ -64,9 +65,24 @@ struct Depot : DepotPool::PoolItem<&_depot_pool> {
 	 */
 	inline bool IsOfType(const Depot *d) const
 	{
-		return GetTileType(d->xy) == GetTileType(this->xy);
+		return d->veh_type == this->veh_type;
 	}
 
+	/**
+	 * Check whether the depot currently is in use; in use means
+	 * that it is not scheduled for deletion and that it still has
+	 * a building on the map. Otherwise the building is demolished
+	 * and the depot awaits to be deleted.
+	 * @return true iff still in use
+	 * @see Depot::Disuse
+	 */
+	inline bool IsInUse() const
+	{
+		return this->delete_ctr == 0;
+	}
+
+	void Disuse();
+
 	/* Check we can add some tiles to this depot. */
 	CommandCost BeforeAddTiles(TileArea ta);
 

src/depot_cmd.cpp

@@ -77,6 +77,20 @@ CommandCost CmdRenameDepot(DoCommandFlag flags, DepotID depot_id, const std::str
 	return CommandCost();
 }
 
+void OnTick_Depot()
+{
+	if (_game_mode == GM_EDITOR) return;
+
+	/* Clean up demolished depots. */
+	for (Depot *d : Depot::Iterate()) {
+		if (d->IsInUse()) continue;
+		if ((_tick_counter + d->index) % DEPOT_REMOVAL_TICKS != 0) continue;
+		if (--d->delete_ctr != 0) continue;
+		delete d;
+	}
+}
+
+
 /**
  * Look for or check depot to join to, building a new one if necessary.
  * @param ta The area of the new depot.

src/depot_gui.cpp

@@ -1095,6 +1095,7 @@ static void DepotSellAllConfirmationCallback(Window *win, bool confirmed)
 	if (confirmed) {
 		assert(Depot::IsValidID(win->window_number));
 		Depot *d = Depot::Get(win->window_number);
+		if (!d->IsInUse()) return;
 		Command<CMD_DEPOT_SELL_ALL_VEHICLES>::Post(d->xy, d->veh_type);
 	}
 }

src/landscape.cpp

@@ -1503,6 +1503,7 @@ void GenerateLandscape(byte mode)
 void OnTick_Town();
 void OnTick_Trees();
 void OnTick_Station();
+void OnTick_Depot();
 void OnTick_Industry();
 
 void OnTick_Companies();
@@ -1516,6 +1517,7 @@ void CallLandscapeTick()
 		OnTick_Town();
 		OnTick_Trees();
 		OnTick_Station();
+		OnTick_Depot();
 		OnTick_Industry();
 	}
 

src/order_cmd.cpp

@@ -820,7 +820,7 @@ CommandCost CmdInsertOrder(DoCommandFlag flags, VehicleID veh, VehicleOrderID se
 			if ((new_order.GetDepotActionType() & ODATFB_NEAREST_DEPOT) == 0) {
 				const Depot *dp = Depot::GetIfValid(new_order.GetDestination());
 
-				if (dp == nullptr) return CMD_ERROR;
+				if (dp == nullptr || !dp->IsInUse()) return CMD_ERROR;
 
 				CommandCost ret = CheckOwnership(dp->company);
 				if (ret.Failed()) return ret;

src/saveload/afterload.cpp

@@ -2807,6 +2807,7 @@ bool AfterLoadGame()
 				/* It can happen there is no depot here anymore (TTO/TTD savegames) */
 				depot->veh_type = VEH_INVALID;
 				depot->company = INVALID_COMPANY;
+				depot->Disuse();
 				delete depot;
 				continue;
 			}

src/saveload/depot_sl.cpp

@@ -32,6 +32,7 @@ static const SaveLoad _depot_desc[] = {
 	 SLE_CONDVAR(Depot, ta.tile,    SLE_UINT32,                 SLV_MULTITILE_DEPOTS, SL_MAX_VERSION),
 	 SLE_CONDVAR(Depot, ta.w,       SLE_FILE_U8 | SLE_VAR_U16,  SLV_MULTITILE_DEPOTS, SL_MAX_VERSION),
 	 SLE_CONDVAR(Depot, ta.h,       SLE_FILE_U8 | SLE_VAR_U16,  SLV_MULTITILE_DEPOTS, SL_MAX_VERSION),
+	 SLE_CONDVAR(Depot, delete_ctr, SLE_UINT8,                  SLV_MULTITILE_DEPOTS, SL_MAX_VERSION),
 };
 
 struct DEPTChunkHandler : ChunkHandler {

src/script/api/script_depotlist.cpp

@@ -21,8 +21,8 @@ ScriptDepotList::ScriptDepotList(ScriptTile::TransportType transport_type)
 	static_assert(VEH_SHIP  == (int)ScriptTile::TRANSPORT_WATER);
 
 	for (const Depot *depot : Depot::Iterate()) {
-		if (depot->veh_type != (VehicleType)transport_type) continue;
-		if (::GetTileOwner(depot->xy) != ScriptObject::GetCompany() && ScriptObject::GetCompany() != OWNER_DEITY) continue;
+		if (!depot->IsInUse() || depot->veh_type != (VehicleType)transport_type) continue;
+		if (depot->company != ScriptObject::GetCompany() && ScriptObject::GetCompany() != OWNER_DEITY) continue;
 
 		/* It only returns one hangar per airport. Anyway, new aircraft is always built in this hangar and not others. */
 		for (auto const &tile : depot->depot_tiles) this->AddItem(tile);

src/ship_cmd.cpp

@@ -154,7 +154,7 @@ static const Depot *FindClosestShipDepot(const Vehicle *v, uint max_distance)
 	uint best_dist = max_distance == 0 ? UINT_MAX : max_distance + 1;
 
 	for (const Depot *depot : Depot::Iterate()) {
-		if (depot->veh_type == VEH_SHIP && depot->company == v->owner) {
+		if (depot->veh_type == VEH_SHIP && depot->company == v->owner && depot->IsInUse()) {
 			uint dist = DistanceManhattan(depot->xy, v->tile);
 			if (dist < best_dist) {
 				best_dist = dist;