Change: Keep removed depots in the pool for a while. (based on patch by adf, #6328, #7051)

src/build_vehicle_gui.cpp

@@ -1276,6 +1276,9 @@ 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;
 		}
@@ -1469,18 +1472,17 @@ struct BuildVehicleWindow : Window {
 		EngineID sel_id = INVALID_ENGINE;
 		this->eng_list.clear();
 
-		for (const Engine *e : Engine::IterateType(VEH_SHIP)) {
+		if (this->listview_mode || this->filter.railtypes != RAILTYPES_NONE) {
-			if (!this->show_hidden_engines && e->IsVariantHidden(_local_company)) continue;
+			for (const Engine *e : Engine::IterateType(VEH_SHIP)) {
-			EngineID eid = e->index;
+				if (!this->show_hidden_engines && e->IsVariantHidden(_local_company)) continue;
-			if (!IsEngineBuildable(eid, VEH_SHIP, _local_company)) continue;
+				EngineID eid = e->index;
+				if (!IsEngineBuildable(eid, VEH_SHIP, _local_company)) continue;
+				this->eng_list.emplace_back(eid, e->info.variant_id, e->display_flags, 0);
 
-			/* Filter by name or NewGRF extra text */
+				if (eid == this->sel_engine) sel_id = eid;
-			if (!FilterByText(e)) continue;
+			}
-
-			this->eng_list.emplace_back(eid, e->info.variant_id, e->display_flags, 0);
-
-			if (eid == this->sel_engine) sel_id = eid;
 		}
+
 		this->SelectEngine(sel_id);
 	}
 

src/depot.cpp

@@ -61,6 +61,23 @@ Depot::~Depot()
 	CloseWindowById(GetWindowClassForVehicleType(this->veh_type),
 			VehicleListIdentifier(VL_DEPOT_LIST,
 			this->veh_type, this->owner, 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;
 }
 
 /**
@@ -139,7 +156,8 @@ void Depot::AfterAddRemove(TileArea ta, bool adding)
 		assert(!this->depot_tiles.empty());
 		this->xy = this->depot_tiles[0];
 	} else {
-		delete this;
+		assert(this->IsInUse());
+		this->Disuse();
 	}
 
 	InvalidateWindowData(WC_SELECT_DEPOT, veh_type);

src/depot_base.h

@@ -32,6 +32,7 @@ struct Depot : DepotPool::PoolItem<&_depot_pool> {
 
 	VehicleType veh_type;   ///< Vehicle type of the depot.
 	Owner owner;            ///< Owner of the depot.
+	uint8_t delete_ctr;     ///< Delete counter. If greater than 0 then it is decremented until it reaches 0; the depot is then deleted.
 	Station *station;       ///< For aircraft, station associated with this hangar.
 
 	union {
@@ -67,9 +68,24 @@ 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

@@ -17,6 +17,7 @@
 #include "vehiclelist.h"
 #include "window_func.h"
 #include "depot_cmd.h"
+#include "timer/timer_game_tick.h"
 
 #include "table/strings.h"
 
@@ -76,6 +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 ((TimerGameTick::counter + d->index) % Ticks::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

@@ -1133,6 +1133,7 @@ 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

@@ -1654,6 +1654,7 @@ bool GenerateLandscape(uint8_t mode)
 void OnTick_Town();
 void OnTick_Trees();
 void OnTick_Station();
+void OnTick_Depot();
 void OnTick_Industry();
 
 void OnTick_Companies();
@@ -1667,6 +1668,7 @@ void CallLandscapeTick()
 		OnTick_Town();
 		OnTick_Trees();
 		OnTick_Station();
+		OnTick_Depot();
 		OnTick_Industry();
 	}
 

src/order_cmd.cpp

@@ -787,7 +787,7 @@ 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;
 
 				ret = CheckOwnership(dp->owner);
 				if (ret.Failed()) return ret;

src/saveload/afterload.cpp

@@ -2844,6 +2844,7 @@ bool AfterLoadGame()
 				/* It can happen there is no depot here anymore (TTO/TTD savegames) */
 				depot->veh_type = VEH_INVALID;
 				depot->owner = INVALID_OWNER;
+				depot->Disuse();
 				delete depot;
 				continue;
 			}

src/saveload/depot_sl.cpp

@@ -33,6 +33,7 @@ static const SaveLoad _depot_desc[] = {
 	 SLE_CONDVAR(Depot, ta.w,       SLE_FILE_U8 | SLE_VAR_U16,  SLV_ADD_MEMBERS_TO_DEPOT_STRUCT, SL_MAX_VERSION),
 	 SLE_CONDVAR(Depot, ta.h,       SLE_FILE_U8 | SLE_VAR_U16,  SLV_ADD_MEMBERS_TO_DEPOT_STRUCT, SL_MAX_VERSION),
 	 SLE_CONDREF(Depot, station,    REF_STATION,                SLV_ADD_MEMBERS_TO_DEPOT_STRUCT, SL_MAX_VERSION),
+	 SLE_CONDVAR(Depot, delete_ctr, SLE_UINT8,                          SLV_KEEP_REMOVED_DEPOTS, SL_MAX_VERSION),
 };
 
 struct DEPTChunkHandler : ChunkHandler {

src/saveload/saveload.h

@@ -395,6 +395,8 @@ enum SaveLoadVersion : uint16_t {
 	SLV_DEPOT_SPREAD,                       ///< 318  PR#XXXXX Add a setting for max depot spread.
 	SLV_ALLOW_INCOMPATIBLE_REPLACEMENTS,    ///< 319  PR#XXXXX Allow incompatible vehicle replacements.
 
+	SLV_KEEP_REMOVED_DEPOTS,                ///< 320  PR#XXXXX Keep remove depots for a while.
+
 	SL_MAX_VERSION,                         ///< Highest possible saveload version
 };
 

src/script/api/script_depotlist.cpp

@@ -24,7 +24,7 @@ ScriptDepotList::ScriptDepotList(ScriptTile::TransportType transport_type)
 	bool is_deity = ScriptCompanyMode::IsDeity();
 	CompanyID owner = ScriptObject::GetCompany();
 	for (const Depot *depot : Depot::Iterate()) {
-		if (depot->veh_type != (VehicleType)transport_type ||
+		if (!depot->IsInUse() || depot->veh_type != (VehicleType)transport_type ||
 			(!is_deity && ::GetTileOwner(depot->xy) != owner)) continue;
 
 		this->AddItem(depot->xy.base());

src/ship_cmd.cpp

@@ -187,7 +187,7 @@ static const Depot *FindClosestShipDepot(const Vehicle *v, uint max_distance)
 	const Depot *best_depot = nullptr;
 	uint best_dist_sq = std::numeric_limits<uint>::max();
 	for (const Depot *depot : Depot::Iterate()) {
-		if (depot->veh_type != VEH_SHIP || depot->owner != v->owner) continue;
+		if (depot->veh_type != VEH_SHIP || depot->owner != v->owner || !depot->IsInUse()) continue;
 
 		const TileIndex tile = depot->xy;
 		const uint dist_sq = DistanceSquare(tile, v->tile);

src/timer/timer_game_tick.h

@@ -78,6 +78,7 @@ public:
 	static constexpr TimerGameTick::Ticks STATION_RATING_TICKS = 185; ///< Cycle duration for updating station rating.
 	static constexpr TimerGameTick::Ticks STATION_ACCEPTANCE_TICKS = 250; ///< Cycle duration for updating station acceptance.
 	static constexpr TimerGameTick::Ticks STATION_LINKGRAPH_TICKS = 504; ///< Cycle duration for cleaning dead links.
+	static constexpr TimerGameTick::Ticks DEPOT_REMOVAL_TICKS = 250; ///< Cycle duration for cleaning demolished depots.
 	static constexpr TimerGameTick::Ticks CARGO_AGING_TICKS = 185; ///< Cycle duration for aging cargo.
 	static constexpr TimerGameTick::Ticks INDUSTRY_PRODUCE_TICKS = 256; ///< Cycle duration for industry production.
 	static constexpr TimerGameTick::Ticks TOWN_GROWTH_TICKS = 70;  ///< Cycle duration for towns trying to grow (this originates from the size of the town array in TTD).

src/viewport.cpp

@@ -3613,6 +3613,10 @@ void MarkCatchmentTilesDirty()
 		MarkWholeScreenDirty();
 	}
 	if (_viewport_highlight_depot != INVALID_DEPOT) {
+		Depot *dep = Depot::Get(_viewport_highlight_depot);
+		if (!dep->IsInUse()) {
+			_viewport_highlight_depot = INVALID_DEPOT;
+		}
 		MarkWholeScreenDirty();
 	}
 }