Codechange: remove the special station/vehicle code from SaveLoad

With the new SLEG_STRUCT it is much easier to embed a struct
in a struct, where the sub-struct has limitations on when it is
being used.
This makes both the code easier to read (less magic) and avoids
the SaveLoad needing to know all these things about Stations
and Vehicles.

1 files changed, 106 insertions, 70 deletions

diff --git a/src/saveload/station_sl.cpp b/src/saveload/station_sl.cpp
index 92fa2bafd..9c07834e4 100644
--- a/src/saveload/station_sl.cpp
+++ b/src/saveload/station_sl.cpp
@@ -374,89 +374,125 @@ static void Ptrs_STNS()
 	}
 }
 
+static OldPersistentStorage _old_st_persistent_storage;
 
-static const SaveLoad _base_station_desc[] = {
-	      SLE_VAR(BaseStation, xy,                     SLE_UINT32),
-	      SLE_REF(BaseStation, town,                   REF_TOWN),
-	      SLE_VAR(BaseStation, string_id,              SLE_STRINGID),
-	     SLE_SSTR(BaseStation, name,                   SLE_STR | SLF_ALLOW_CONTROL),
-	      SLE_VAR(BaseStation, delete_ctr,             SLE_UINT8),
-	      SLE_VAR(BaseStation, owner,                  SLE_UINT8),
-	      SLE_VAR(BaseStation, facilities,             SLE_UINT8),
-	      SLE_VAR(BaseStation, build_date,             SLE_INT32),
+/**
+ * SaveLoad handler for the BaseStation, which all other stations / waypoints
+ * make use of.
+ */
+class SlStationBase : public DefaultSaveLoadHandler<SlStationBase, BaseStation> {
+public:
+	inline static const SaveLoad description[] = {
+		    SLE_VAR(BaseStation, xy,                     SLE_UINT32),
+		    SLE_REF(BaseStation, town,                   REF_TOWN),
+		    SLE_VAR(BaseStation, string_id,              SLE_STRINGID),
+		   SLE_SSTR(BaseStation, name,                   SLE_STR | SLF_ALLOW_CONTROL),
+		    SLE_VAR(BaseStation, delete_ctr,             SLE_UINT8),
+		    SLE_VAR(BaseStation, owner,                  SLE_UINT8),
+		    SLE_VAR(BaseStation, facilities,             SLE_UINT8),
+		    SLE_VAR(BaseStation, build_date,             SLE_INT32),
+
+		/* Used by newstations for graphic variations */
+		    SLE_VAR(BaseStation, random_bits,            SLE_UINT16),
+		    SLE_VAR(BaseStation, waiting_triggers,       SLE_UINT8),
+		    SLE_VAR(BaseStation, num_specs,              SLE_UINT8),
+	};
 
-	/* Used by newstations for graphic variations */
-	      SLE_VAR(BaseStation, random_bits,            SLE_UINT16),
-	      SLE_VAR(BaseStation, waiting_triggers,       SLE_UINT8),
-	      SLE_VAR(BaseStation, num_specs,              SLE_UINT8),
+	void GenericSaveLoad(BaseStation *bst) const
+	{
+		SlObject(bst, this->GetDescription());
+	}
+
+	void Save(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
+	void Load(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
+	void FixPointers(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
 };
 
-static OldPersistentStorage _old_st_persistent_storage;
+/**
+ * SaveLoad handler for a normal station (read: not a waypoint).
+ */
+class SlStationNormal : public DefaultSaveLoadHandler<SlStationNormal, BaseStation> {
+public:
+	inline static const SaveLoad description[] = {
+		SLEG_STRUCT(SlStationBase),
+		    SLE_VAR(Station, train_station.tile,         SLE_UINT32),
+		    SLE_VAR(Station, train_station.w,            SLE_FILE_U8 | SLE_VAR_U16),
+		    SLE_VAR(Station, train_station.h,            SLE_FILE_U8 | SLE_VAR_U16),
+
+		    SLE_REF(Station, bus_stops,                  REF_ROADSTOPS),
+		    SLE_REF(Station, truck_stops,                REF_ROADSTOPS),
+		SLE_CONDNULL(4, SL_MIN_VERSION, SLV_MULTITILE_DOCKS),
+		SLE_CONDVAR(Station, ship_station.tile,          SLE_UINT32,                SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
+		SLE_CONDVAR(Station, ship_station.w,             SLE_FILE_U8 | SLE_VAR_U16, SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
+		SLE_CONDVAR(Station, ship_station.h,             SLE_FILE_U8 | SLE_VAR_U16, SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
+		SLE_CONDVAR(Station, docking_station.tile,       SLE_UINT32,                SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
+		SLE_CONDVAR(Station, docking_station.w,          SLE_FILE_U8 | SLE_VAR_U16, SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
+		SLE_CONDVAR(Station, docking_station.h,          SLE_FILE_U8 | SLE_VAR_U16, SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
+		    SLE_VAR(Station, airport.tile,               SLE_UINT32),
+		SLE_CONDVAR(Station, airport.w,                  SLE_FILE_U8 | SLE_VAR_U16, SLV_140, SL_MAX_VERSION),
+		SLE_CONDVAR(Station, airport.h,                  SLE_FILE_U8 | SLE_VAR_U16, SLV_140, SL_MAX_VERSION),
+		    SLE_VAR(Station, airport.type,               SLE_UINT8),
+		SLE_CONDVAR(Station, airport.layout,             SLE_UINT8,                 SLV_145, SL_MAX_VERSION),
+		    SLE_VAR(Station, airport.flags,              SLE_UINT64),
+		SLE_CONDVAR(Station, airport.rotation,           SLE_UINT8,                 SLV_145, SL_MAX_VERSION),
+		SLEG_CONDARR(_old_st_persistent_storage.storage,  SLE_UINT32, 16,            SLV_145, SLV_161),
+		SLE_CONDREF(Station, airport.psa,                REF_STORAGE,               SLV_161, SL_MAX_VERSION),
+
+		    SLE_VAR(Station, indtype,                    SLE_UINT8),
+
+		    SLE_VAR(Station, time_since_load,            SLE_UINT8),
+		    SLE_VAR(Station, time_since_unload,          SLE_UINT8),
+		    SLE_VAR(Station, last_vehicle_type,          SLE_UINT8),
+		    SLE_VAR(Station, had_vehicle_of_type,        SLE_UINT8),
+		SLE_REFLIST(Station, loading_vehicles,           REF_VEHICLE),
+		SLE_CONDVAR(Station, always_accepted,            SLE_FILE_U32 | SLE_VAR_U64, SLV_127, SLV_EXTEND_CARGOTYPES),
+		SLE_CONDVAR(Station, always_accepted,            SLE_UINT64,                 SLV_EXTEND_CARGOTYPES, SL_MAX_VERSION),
+	};
 
-static const SaveLoad _station_desc[] = {
-	SLE_WRITEBYTE(Station, facilities),
-	SLE_ST_INCLUDE(),
-
-	      SLE_VAR(Station, train_station.tile,         SLE_UINT32),
-	      SLE_VAR(Station, train_station.w,            SLE_FILE_U8 | SLE_VAR_U16),
-	      SLE_VAR(Station, train_station.h,            SLE_FILE_U8 | SLE_VAR_U16),
-
-	      SLE_REF(Station, bus_stops,                  REF_ROADSTOPS),
-	      SLE_REF(Station, truck_stops,                REF_ROADSTOPS),
-	 SLE_CONDNULL(4, SL_MIN_VERSION, SLV_MULTITILE_DOCKS),
-	  SLE_CONDVAR(Station, ship_station.tile,          SLE_UINT32,                SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
-	  SLE_CONDVAR(Station, ship_station.w,             SLE_FILE_U8 | SLE_VAR_U16, SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
-	  SLE_CONDVAR(Station, ship_station.h,             SLE_FILE_U8 | SLE_VAR_U16, SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
-	  SLE_CONDVAR(Station, docking_station.tile,       SLE_UINT32,                SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
-	  SLE_CONDVAR(Station, docking_station.w,          SLE_FILE_U8 | SLE_VAR_U16, SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
-	  SLE_CONDVAR(Station, docking_station.h,          SLE_FILE_U8 | SLE_VAR_U16, SLV_MULTITILE_DOCKS, SL_MAX_VERSION),
-	      SLE_VAR(Station, airport.tile,               SLE_UINT32),
-	  SLE_CONDVAR(Station, airport.w,                  SLE_FILE_U8 | SLE_VAR_U16, SLV_140, SL_MAX_VERSION),
-	  SLE_CONDVAR(Station, airport.h,                  SLE_FILE_U8 | SLE_VAR_U16, SLV_140, SL_MAX_VERSION),
-	      SLE_VAR(Station, airport.type,               SLE_UINT8),
-	  SLE_CONDVAR(Station, airport.layout,             SLE_UINT8,                 SLV_145, SL_MAX_VERSION),
-	      SLE_VAR(Station, airport.flags,              SLE_UINT64),
-	  SLE_CONDVAR(Station, airport.rotation,           SLE_UINT8,                 SLV_145, SL_MAX_VERSION),
-	 SLEG_CONDARR(_old_st_persistent_storage.storage,  SLE_UINT32, 16,            SLV_145, SLV_161),
-	  SLE_CONDREF(Station, airport.psa,                REF_STORAGE,               SLV_161, SL_MAX_VERSION),
-
-	      SLE_VAR(Station, indtype,                    SLE_UINT8),
-
-	      SLE_VAR(Station, time_since_load,            SLE_UINT8),
-	      SLE_VAR(Station, time_since_unload,          SLE_UINT8),
-	      SLE_VAR(Station, last_vehicle_type,          SLE_UINT8),
-	      SLE_VAR(Station, had_vehicle_of_type,        SLE_UINT8),
-	  SLE_REFLIST(Station, loading_vehicles,           REF_VEHICLE),
-	  SLE_CONDVAR(Station, always_accepted,            SLE_FILE_U32 | SLE_VAR_U64, SLV_127, SLV_EXTEND_CARGOTYPES),
-	  SLE_CONDVAR(Station, always_accepted,            SLE_UINT64,                 SLV_EXTEND_CARGOTYPES, SL_MAX_VERSION),
+	void GenericSaveLoad(BaseStation *bst) const
+	{
+		if ((bst->facilities & FACIL_WAYPOINT) != 0) return;
+		SlObject(bst, this->GetDescription());
+	}
+
+	void Save(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
+	void Load(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
+	void FixPointers(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
 };
 
-static const SaveLoad _waypoint_desc[] = {
-	SLE_WRITEBYTE(Waypoint, facilities),
-	SLE_ST_INCLUDE(),
+class SlStationWaypoint : public DefaultSaveLoadHandler<SlStationWaypoint, BaseStation> {
+public:
+	inline static const SaveLoad description[] = {
+		SLEG_STRUCT(SlStationBase),
+		    SLE_VAR(Waypoint, town_cn,                   SLE_UINT16),
+
+		SLE_CONDVAR(Waypoint, train_station.tile,        SLE_UINT32,                  SLV_124, SL_MAX_VERSION),
+		SLE_CONDVAR(Waypoint, train_station.w,           SLE_FILE_U8 | SLE_VAR_U16,   SLV_124, SL_MAX_VERSION),
+		SLE_CONDVAR(Waypoint, train_station.h,           SLE_FILE_U8 | SLE_VAR_U16,   SLV_124, SL_MAX_VERSION),
+	};
 
-	      SLE_VAR(Waypoint, town_cn,                   SLE_UINT16),
+	void GenericSaveLoad(BaseStation *bst) const
+	{
+		if ((bst->facilities & FACIL_WAYPOINT) == 0) return;
+		SlObject(bst, this->GetDescription());
+	}
 
-	  SLE_CONDVAR(Waypoint, train_station.tile,        SLE_UINT32,                  SLV_124, SL_MAX_VERSION),
-	  SLE_CONDVAR(Waypoint, train_station.w,           SLE_FILE_U8 | SLE_VAR_U16,   SLV_124, SL_MAX_VERSION),
-	  SLE_CONDVAR(Waypoint, train_station.h,           SLE_FILE_U8 | SLE_VAR_U16,   SLV_124, SL_MAX_VERSION),
+	void Save(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
+	void Load(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
+	void FixPointers(BaseStation *bst) const override { this->GenericSaveLoad(bst); }
 };
 
-/**
- * Get the base station description to be used for SL_ST_INCLUDE
- * @return the base station description.
- */
-SaveLoadTable GetBaseStationDescription()
-{
-	return _base_station_desc;
-}
+static const SaveLoad _station_desc[] = {
+	SLE_SAVEBYTE(BaseStation, facilities),
+	SLEG_STRUCT(SlStationNormal),
+	SLEG_STRUCT(SlStationWaypoint),
+};
 
 static void RealSave_STNN(BaseStation *bst)
 {
-	bool waypoint = (bst->facilities & FACIL_WAYPOINT) != 0;
-	SlObject(bst, waypoint ? SaveLoadTable(_waypoint_desc) : SaveLoadTable(_station_desc));
+	SlObject(bst, _station_desc);
 
-	if (!waypoint) {
+	if ((bst->facilities & FACIL_WAYPOINT) == 0) {
 		Station *st = Station::From(bst);
 		for (CargoID i = 0; i < NUM_CARGO; i++) {
 			_num_dests = (uint32)st->goods[i].cargo.Packets()->MapSize();
@@ -509,7 +545,7 @@ static void Load_STNN()
 		bool waypoint = (SlReadByte() & FACIL_WAYPOINT) != 0;
 
 		BaseStation *bst = waypoint ? (BaseStation *)new (index) Waypoint() : new (index) Station();
-		SlObject(bst, waypoint ? SaveLoadTable(_waypoint_desc) : SaveLoadTable(_station_desc));
+		SlObject(bst, _station_desc);
 
 		if (!waypoint) {
 			Station *st = Station::From(bst);
@@ -583,7 +619,7 @@ static void Ptrs_STNN()
 	}
 
 	for (Waypoint *wp : Waypoint::Iterate()) {
-		SlObject(wp, _waypoint_desc);
+		SlObject(wp, _station_desc);
 	}
 }