Improve performance of name sorting in town and station list windows

src/base_station_base.h

@@ -17,6 +17,8 @@
 #include "viewport_type.h"
 #include "station_map.h"
 #include "core/geometry_type.hpp"
+#include "core/alloc_type.hpp"
+#include <memory>
 
 typedef Pool<BaseStation, StationID, 32, 64000> StationPool;
 extern StationPool _station_pool;
@@ -59,6 +61,7 @@ struct BaseStation : StationPool::PoolItem<&_station_pool> {
 
 	char *name;                     ///< Custom name
 	StringID string_id;             ///< Default name (town area) of station
+	std::unique_ptr<const char, FreeDeleter> cached_name; ///< NOSAVE: Cache of the resolved name of the station, if not using a custom name
 
 	Town *town;                     ///< The town this station is associated with
 	OwnerByte owner;                ///< The owner of this station
@@ -113,6 +116,13 @@ struct BaseStation : StationPool::PoolItem<&_station_pool> {
 	 */
 	virtual void UpdateVirtCoord() = 0;
 
+	inline const char *GetCachedName() const
+	{
+		if (this->name != nullptr) return this->name;
+		if (!this->cached_name) const_cast<BaseStation *>(this)->FillCachedName();
+		return this->cached_name.get();
+	}
+
 	virtual void MoveSign(TileIndex new_xy)
 	{
 		this->xy = new_xy;
@@ -176,6 +186,9 @@ struct BaseStation : StationPool::PoolItem<&_station_pool> {
 	}
 
 	static void PostDestructor(size_t index);
+
+	private:
+	void FillCachedName();
 };
 
 #define FOR_ALL_BASE_STATIONS(var) FOR_ALL_ITEMS_FROM(BaseStation, station_index, var, 0)