Codechange: use std::string as script API return type

src/script/api/script_basestation.cpp

@@ -26,9 +26,9 @@
 	return st != nullptr && (st->owner == ScriptObject::GetCompany() || ScriptCompanyMode::IsDeity() || st->owner == OWNER_NONE);
 }
 
-/* static */ char *ScriptBaseStation::GetName(StationID station_id)
+/* static */ std::optional<std::string> ScriptBaseStation::GetName(StationID station_id)
 {
-	if (!IsValidBaseStation(station_id)) return nullptr;
+	if (!IsValidBaseStation(station_id)) return std::nullopt;
 
 	::SetDParam(0, station_id);
 	return GetString(::Station::IsValidID(station_id) ? STR_STATION_NAME : STR_WAYPOINT_NAME);

src/script/api/script_basestation.hpp

@@ -43,7 +43,7 @@ public:
 	 * @pre IsValidBaseStation(station_id).
 	 * @return The name of the station.
 	 */
-	static char *GetName(StationID station_id);
+	static std::optional<std::string> GetName(StationID station_id);
 
 	/**
 	 * Set the name this basestation.

src/script/api/script_bridge.cpp

@@ -129,10 +129,10 @@ static void _DoCommandReturnBuildBridge1(class ScriptInstance *instance)
 	return ScriptObject::Command<CMD_LANDSCAPE_CLEAR>::Do(tile);
 }
 
-/* static */ char *ScriptBridge::GetName(BridgeID bridge_id, ScriptVehicle::VehicleType vehicle_type)
+/* static */ std::optional<std::string> ScriptBridge::GetName(BridgeID bridge_id, ScriptVehicle::VehicleType vehicle_type)
 {
-	EnforcePrecondition(nullptr, vehicle_type == ScriptVehicle::VT_ROAD || vehicle_type == ScriptVehicle::VT_RAIL || vehicle_type == ScriptVehicle::VT_WATER);
-	if (!IsValidBridge(bridge_id)) return nullptr;
+	EnforcePrecondition(std::nullopt, vehicle_type == ScriptVehicle::VT_ROAD || vehicle_type == ScriptVehicle::VT_RAIL || vehicle_type == ScriptVehicle::VT_WATER);
+	if (!IsValidBridge(bridge_id)) return std::nullopt;
 
 	return GetString(vehicle_type == ScriptVehicle::VT_WATER ? STR_LAI_BRIDGE_DESCRIPTION_AQUEDUCT : ::GetBridgeSpec(bridge_id)->transport_name[vehicle_type]);
 }

src/script/api/script_bridge.hpp

@@ -69,7 +69,7 @@ public:
 	 * @pre vehicle_type == ScriptVehicle::VT_ROAD || vehicle_type == ScriptVehicle::VT_RAIL || vehicle_type == ScriptVehicle::VT_WATER
 	 * @return The name the bridge has.
 	 */
-	static char *GetName(BridgeID bridge_id, ScriptVehicle::VehicleType vehicle_type);
+	static std::optional<std::string> GetName(BridgeID bridge_id, ScriptVehicle::VehicleType vehicle_type);
 
 	/**
 	 * Get the maximum speed of a bridge.

src/script/api/script_cargo.cpp

@@ -28,26 +28,25 @@
 	return (towneffect_type >= (TownEffect)TE_BEGIN && towneffect_type < (TownEffect)TE_END);
 }
 
-/* static */ char *ScriptCargo::GetName(CargoID cargo_type)
+/* static */ std::optional<std::string> ScriptCargo::GetName(CargoID cargo_type)
 {
-	if (!IsValidCargo(cargo_type)) return nullptr;
+	if (!IsValidCargo(cargo_type)) return std::nullopt;
 
 	::SetDParam(0, 1ULL << cargo_type);
 	return GetString(STR_JUST_CARGO_LIST);
 }
 
-/* static */ char *ScriptCargo::GetCargoLabel(CargoID cargo_type)
+/* static */ std::optional<std::string> ScriptCargo::GetCargoLabel(CargoID cargo_type)
 {
-	if (!IsValidCargo(cargo_type)) return nullptr;
+	if (!IsValidCargo(cargo_type)) return std::nullopt;
 	const CargoSpec *cargo = ::CargoSpec::Get(cargo_type);
 
 	/* cargo->label is a uint32 packing a 4 character non-terminated string,
 	 * like "PASS", "COAL", "OIL_". New ones can be defined by NewGRFs */
-	char *cargo_label = MallocT<char>(sizeof(cargo->label) + 1);
+	std::string cargo_label;
 	for (uint i = 0; i < sizeof(cargo->label); i++) {
-		cargo_label[i] = GB(cargo->label, (uint8)(sizeof(cargo->label) - i - 1) * 8, 8);
+		cargo_label.push_back(GB(cargo->label, (uint8)(sizeof(cargo->label) - i - 1) * 8, 8));
 	}
-	cargo_label[sizeof(cargo->label)] = '\0';
 	return cargo_label;
 }
 

src/script/api/script_cargo.hpp

@@ -90,7 +90,7 @@ public:
 	 * @pre IsValidCargo(cargo_type).
 	 * @return The name of the cargo type.
 	 */
-	static char *GetName(CargoID cargo_type);
+	static std::optional<std::string> GetName(CargoID cargo_type);
 
 	/**
 	 * Gets the string representation of the cargo label.
@@ -107,7 +107,7 @@ public:
 	 *  - In other words: Only use the cargo label, if you know more about the behaviour
 	 *    of a specific cargo from a specific industry set, than the API methods can tell you.
 	 */
-	static char *GetCargoLabel(CargoID cargo_type);
+	static std::optional<std::string> GetCargoLabel(CargoID cargo_type);
 
 	/**
 	 * Checks whether the give cargo is a freight or not.

src/script/api/script_client.cpp

@@ -32,11 +32,11 @@ static NetworkClientInfo *FindClientInfo(ScriptClient::ClientID client)
 	return (FindClientInfo(client) == nullptr ? ScriptClient::CLIENT_INVALID : client);
 }
 
-/* static */ char *ScriptClient::GetName(ScriptClient::ClientID client)
+/* static */ std::optional<std::string> ScriptClient::GetName(ScriptClient::ClientID client)
 {
 	NetworkClientInfo *ci = FindClientInfo(client);
-	if (ci == nullptr) return nullptr;
-	return stredup(ci->client_name.c_str());
+	if (ci == nullptr) return std::nullopt;
+	return ci->client_name;
 }
 
 /* static */ ScriptCompany::CompanyID ScriptClient::GetCompany(ScriptClient::ClientID client)

src/script/api/script_client.hpp

@@ -45,7 +45,7 @@ public:
 	 * @pre ResolveClientID(client) != CLIENT_INVALID.
 	 * @return The name of the given client.
 	 */
-	static char *GetName(ClientID client);
+	static std::optional<std::string> GetName(ClientID client);
 
 	/**
 	 * Get the company in which the given client is playing.

src/script/api/script_company.cpp

@@ -57,10 +57,10 @@
 	return ScriptObject::Command<CMD_RENAME_COMPANY>::Do(text);
 }
 
-/* static */ char *ScriptCompany::GetName(ScriptCompany::CompanyID company)
+/* static */ std::optional<std::string> ScriptCompany::GetName(ScriptCompany::CompanyID company)
 {
 	company = ResolveCompanyID(company);
-	if (company == COMPANY_INVALID) return nullptr;
+	if (company == COMPANY_INVALID) return std::nullopt;
 
 	::SetDParam(0, company);
 	return GetString(STR_COMPANY_NAME);
@@ -79,20 +79,13 @@
 	return ScriptObject::Command<CMD_RENAME_PRESIDENT>::Do(text);
 }
 
-/* static */ char *ScriptCompany::GetPresidentName(ScriptCompany::CompanyID company)
+/* static */ std::optional<std::string> ScriptCompany::GetPresidentName(ScriptCompany::CompanyID company)
 {
 	company = ResolveCompanyID(company);
+	if (company == COMPANY_INVALID) return std::nullopt;
 
-	static const int len = 64;
-	char *president_name = MallocT<char>(len);
-	if (company != COMPANY_INVALID) {
-		::SetDParam(0, company);
-		::GetString(president_name, STR_PRESIDENT_NAME, &president_name[len - 1]);
-	} else {
-		*president_name = '\0';
-	}
-
-	return president_name;
+	::SetDParam(0, company);
+	return GetString(STR_PRESIDENT_NAME);
 }
 
 /* static */ bool ScriptCompany::SetPresidentGender(Gender gender)

src/script/api/script_company.hpp

@@ -150,7 +150,7 @@ public:
 	 * @pre ResolveCompanyID(company) != COMPANY_INVALID.
 	 * @return The name of the given company.
 	 */
-	static char *GetName(CompanyID company);
+	static std::optional<std::string> GetName(CompanyID company);
 
 	/**
 	 * Set the name of your president.
@@ -168,7 +168,7 @@ public:
 	 * @pre ResolveCompanyID(company) != COMPANY_INVALID.
 	 * @return The name of the president of the given company.
 	 */
-	static char *GetPresidentName(CompanyID company);
+	static std::optional<std::string> GetPresidentName(CompanyID company);
 
 	/**
 	 * Set the gender of the president of your company.

src/script/api/script_engine.cpp

@@ -41,9 +41,9 @@
 	return e != nullptr && ::IsEngineBuildable(engine_id, e->type, ScriptObject::GetCompany());
 }
 
-/* static */ char *ScriptEngine::GetName(EngineID engine_id)
+/* static */ std::optional<std::string> ScriptEngine::GetName(EngineID engine_id)
 {
-	if (!IsValidEngine(engine_id)) return nullptr;
+	if (!IsValidEngine(engine_id)) return std::nullopt;
 
 	::SetDParam(0, engine_id);
 	return GetString(STR_ENGINE_NAME);

src/script/api/script_engine.hpp

@@ -44,7 +44,7 @@ public:
 	 * @pre IsValidEngine(engine_id).
 	 * @return The name the engine has.
 	 */
-	static char *GetName(EngineID engine_id);
+	static std::optional<std::string> GetName(EngineID engine_id);
 
 	/**
 	 * Get the cargo-type of an engine. In case it can transport multiple cargoes, it

src/script/api/script_error.cpp

@@ -23,9 +23,9 @@ ScriptError::ScriptErrorMapString ScriptError::error_map_string = ScriptError::S
 	return ScriptObject::GetLastError();
 }
 
-/* static */ char *ScriptError::GetLastErrorString()
+/* static */ std::optional<std::string> ScriptError::GetLastErrorString()
 {
-	return stredup((*error_map_string.find(ScriptError::GetLastError())).second);
+	return (*error_map_string.find(ScriptError::GetLastError())).second;
 }
 
 /* static */ ScriptErrorType ScriptError::StringToError(StringID internal_string_id)

src/script/api/script_error.hpp

@@ -193,7 +193,7 @@ public:
 	 * Get the last error in string format (for human readability).
 	 * @return An ErrorMessage enum item, as string.
 	 */
-	static char *GetLastErrorString();
+	static std::optional<std::string> GetLastErrorString();
 
 	/**
 	 * Get the error based on the OpenTTD StringID.

src/script/api/script_event_types.cpp

@@ -28,9 +28,9 @@ bool ScriptEventEnginePreview::IsEngineValid() const
 	return e != nullptr && e->IsEnabled();
 }
 
-char *ScriptEventEnginePreview::GetName()
+std::optional<std::string> ScriptEventEnginePreview::GetName()
 {
-	if (!this->IsEngineValid()) return nullptr;
+	if (!this->IsEngineValid()) return std::nullopt;
 
 	::SetDParam(0, this->engine);
 	return GetString(STR_ENGINE_NAME);

src/script/api/script_event_types.hpp

@@ -239,7 +239,7 @@ public:
 	 * Get the name of the offered engine.
 	 * @return The name the engine has.
 	 */
-	char *GetName();
+	std::optional<std::string> GetName();
 
 	/**
 	 * Get the cargo-type of the offered engine. In case it can transport multiple cargoes, it

src/script/api/script_group.cpp

@@ -68,9 +68,9 @@
 	return ScriptObject::Command<CMD_ALTER_GROUP>::Do(AlterGroupMode::Rename, group_id, 0, text);
 }
 
-/* static */ char *ScriptGroup::GetName(GroupID group_id)
+/* static */ std::optional<std::string> ScriptGroup::GetName(GroupID group_id)
 {
-	if (!IsValidGroup(group_id)) return nullptr;
+	if (!IsValidGroup(group_id)) return std::nullopt;
 
 	::SetDParam(0, group_id);
 	return GetString(STR_GROUP_NAME);

src/script/api/script_group.hpp

@@ -84,7 +84,7 @@ public:
 	 * @pre IsValidGroup(group_id).
 	 * @return The name the group has.
 	 */
-	static char *GetName(GroupID group_id);
+	static std::optional<std::string> GetName(GroupID group_id);
 
 	/**
 	 * Set parent group of a group.

src/script/api/script_industry.cpp

@@ -42,9 +42,9 @@
 	return ::GetIndustryIndex(tile);
 }
 
-/* static */ char *ScriptIndustry::GetName(IndustryID industry_id)
+/* static */ std::optional<std::string> ScriptIndustry::GetName(IndustryID industry_id)
 {
-	if (!IsValidIndustry(industry_id)) return nullptr;
+	if (!IsValidIndustry(industry_id)) return std::nullopt;
 
 	::SetDParam(0, industry_id);
 	return GetString(STR_INDUSTRY_NAME);

src/script/api/script_industry.hpp

@@ -79,7 +79,7 @@ public:
 	 * @pre IsValidIndustry(industry_id).
 	 * @return The name of the industry.
 	 */
-	static char *GetName(IndustryID industry_id);
+	static std::optional<std::string> GetName(IndustryID industry_id);
 
 	/**
 	 * Set the custom text of an industry, shown in the GUI.

src/script/api/script_industrytype.cpp

@@ -57,9 +57,9 @@
 	return ::GetIndustrySpec(industry_type)->GetConstructionCost();
 }
 
-/* static */ char *ScriptIndustryType::GetName(IndustryType industry_type)
+/* static */ std::optional<std::string> ScriptIndustryType::GetName(IndustryType industry_type)
 {
-	if (!IsValidIndustryType(industry_type)) return nullptr;
+	if (!IsValidIndustryType(industry_type)) return std::nullopt;
 
 	return GetString(::GetIndustrySpec(industry_type)->name);
 }

src/script/api/script_industrytype.hpp

@@ -39,7 +39,7 @@ public:
 	 * @pre IsValidIndustryType(industry_type).
 	 * @return The name of an industry.
 	 */
-	static char *GetName(IndustryType industry_type);
+	static std::optional<std::string> GetName(IndustryType industry_type);
 
 	/**
 	 * Get a list of CargoID possible produced by this industry-type.

src/script/api/script_newgrf.cpp

@@ -50,15 +50,15 @@ ScriptNewGRFList::ScriptNewGRFList()
 	return 0;
 }
 
-/* static */ char *ScriptNewGRF::GetName(SQInteger grfid)
+/* static */ std::optional<std::string> ScriptNewGRF::GetName(SQInteger grfid)
 {
 	grfid = BSWAP32(GB(grfid, 0, 32)); // Match people's expectations.
 
 	for (auto c = _grfconfig; c != nullptr; c = c->next) {
 		if (!HasBit(c->flags, GCF_STATIC) && c->ident.grfid == grfid) {
-			return ::stredup(c->GetName());
+			return c->GetName();
 		}
 	}
 
-	return nullptr;
+	return std::nullopt;
 }

src/script/api/script_newgrf.hpp

@@ -50,7 +50,7 @@ public:
 	 * @pre ScriptNewGRF::IsLoaded(grfid).
 	 * @return The name of the NewGRF or null if no name is defined.
 	 */
-	static char *GetName(SQInteger grfid);
+	static std::optional<std::string> GetName(SQInteger grfid);
 };
 
 #endif /* SCRIPT_NEWGRF_HPP */

src/script/api/script_object.cpp

@@ -218,12 +218,9 @@ ScriptObject::ActiveInstance::~ActiveInstance()
 	return GetStorage()->log_data;
 }
 
-/* static */ char *ScriptObject::GetString(StringID string)
+/* static */ std::string ScriptObject::GetString(StringID string)
 {
-	char buffer[64];
-	::GetString(buffer, string, lastof(buffer));
-	::StrMakeValidInPlace(buffer, lastof(buffer), SVS_NONE);
-	return ::stredup(buffer);
+	return ::StrMakeValid(::GetString(string));
 }
 
 /* static */ void ScriptObject::SetCallbackVariable(int index, int value)

src/script/api/script_object.hpp

@@ -282,7 +282,7 @@ protected:
 	/**
 	 * Get an allocated string with all control codes stripped off.
 	 */
-	static char *GetString(StringID string);
+	static std::string GetString(StringID string);
 
 private:
 	/* Helper functions for DoCommand. */

src/script/api/script_objecttype.cpp

@@ -23,9 +23,9 @@
 	return ObjectSpec::Get(object_type)->IsEverAvailable();
 }
 
-/* static */ char *ScriptObjectType::GetName(ObjectType object_type)
+/* static */ std::optional<std::string> ScriptObjectType::GetName(ObjectType object_type)
 {
-	EnforcePrecondition(nullptr, IsValidObjectType(object_type));
+	EnforcePrecondition(std::nullopt, IsValidObjectType(object_type));
 
 	return GetString(ObjectSpec::Get(object_type)->name);
 }

src/script/api/script_objecttype.hpp

@@ -33,7 +33,7 @@ public:
 	 * @pre IsValidObjectType(object_type).
 	 * @return The name of an object.
 	 */
-	static char *GetName(ObjectType object_type);
+	static std::optional<std::string> GetName(ObjectType object_type);
 
 	/**
 	 * Get the number of views for an object-type.

src/script/api/script_rail.cpp

@@ -24,9 +24,9 @@
 
 #include "../../safeguards.h"
 
-/* static */ char *ScriptRail::GetName(RailType rail_type)
+/* static */ std::optional<std::string> ScriptRail::GetName(RailType rail_type)
 {
-	if (!IsRailTypeAvailable(rail_type)) return nullptr;
+	if (!IsRailTypeAvailable(rail_type)) return std::nullopt;
 
 	return GetString(GetRailTypeInfo((::RailType)rail_type)->strings.menu_text);
 }

src/script/api/script_rail.hpp

@@ -101,7 +101,7 @@ public:
 	 *  means that the name could be something like "Maglev construction" instead
 	 *  of just "Maglev".
 	 */
-	static char *GetName(RailType rail_type);
+	static std::optional<std::string> GetName(RailType rail_type);
 
 	/**
 	 * Checks whether the given tile is actually a tile with rail that can be

src/script/api/script_road.cpp

@@ -25,9 +25,9 @@
 	return ScriptCargo::HasCargoClass(cargo_type, ScriptCargo::CC_PASSENGERS) ? ROADVEHTYPE_BUS : ROADVEHTYPE_TRUCK;
 }
 
-/* static */ char *ScriptRoad::GetName(RoadType road_type)
+/* static */ std::optional<std::string> ScriptRoad::GetName(RoadType road_type)
 {
-	if (!IsRoadTypeAvailable(road_type)) return nullptr;
+	if (!IsRoadTypeAvailable(road_type)) return std::nullopt;
 
 	return GetString(GetRoadTypeInfo((::RoadType)road_type)->strings.name);
 }

src/script/api/script_road.hpp

@@ -90,7 +90,7 @@ public:
 	 * @pre IsRoadTypeAvailable(road_type).
 	 * @return The name the road type has.
 	 */
-	static char *GetName(RoadType road_type);
+	static std::optional<std::string> GetName(RoadType road_type);
 
 	/**
 	 * Determines whether a busstop or a truckstop is needed to transport a certain cargo.

src/script/api/script_sign.cpp

@@ -47,9 +47,9 @@
 	return ScriptObject::Command<CMD_RENAME_SIGN>::Do(sign_id, text);
 }
 
-/* static */ char *ScriptSign::GetName(SignID sign_id)
+/* static */ std::optional<std::string> ScriptSign::GetName(SignID sign_id)
 {
-	if (!IsValidSign(sign_id)) return nullptr;
+	if (!IsValidSign(sign_id)) return std::nullopt;
 
 	::SetDParam(0, sign_id);
 	return GetString(STR_SIGN_NAME);

src/script/api/script_sign.hpp

@@ -55,7 +55,7 @@ public:
 	 * @pre IsValidSign(sign_id).
 	 * @return The name of the sign.
 	 */
-	static char *GetName(SignID sign_id);
+	static std::optional<std::string> GetName(SignID sign_id);
 
 	/**
 	 * Get the owner of a sign.

src/script/api/script_town.cpp

@@ -32,9 +32,9 @@
 	return ::Town::IsValidID(town_id);
 }
 
-/* static */ char *ScriptTown::GetName(TownID town_id)
+/* static */ std::optional<std::string> ScriptTown::GetName(TownID town_id)
 {
-	if (!IsValidTown(town_id)) return nullptr;
+	if (!IsValidTown(town_id)) return std::nullopt;
 
 	::SetDParam(0, town_id);
 	return GetString(STR_TOWN_NAME);

src/script/api/script_town.hpp

@@ -142,7 +142,7 @@ public:
 	 * @pre IsValidTown(town_id).
 	 * @return The name of the town.
 	 */
-	static char *GetName(TownID town_id);
+	static std::optional<std::string> GetName(TownID town_id);
 
 	/**
 	 * Rename a town.

src/script/api/script_vehicle.cpp

@@ -299,9 +299,9 @@
 	return ::Vehicle::Get(vehicle_id)->unitnumber;
 }
 
-/* static */ char *ScriptVehicle::GetName(VehicleID vehicle_id)
+/* static */ std::optional<std::string> ScriptVehicle::GetName(VehicleID vehicle_id)
 {
-	if (!IsPrimaryVehicle(vehicle_id)) return nullptr;
+	if (!IsPrimaryVehicle(vehicle_id)) return std::nullopt;
 
 	::SetDParam(0, vehicle_id);
 	return GetString(STR_VEHICLE_NAME);

src/script/api/script_vehicle.hpp

@@ -137,7 +137,7 @@ public:
 	 * @pre IsPrimaryVehicle(vehicle_id).
 	 * @return The name the vehicle has.
 	 */
-	static char *GetName(VehicleID vehicle_id);
+	static std::optional<std::string> GetName(VehicleID vehicle_id);
 
 	/**
 	 * Get the owner of a vehicle.

src/script/squirrel_helper.hpp

@@ -52,11 +52,22 @@ namespace SQConvert {
 	template <> struct Return<Money>        { static inline int Set(HSQUIRRELVM vm, Money res)       { sq_pushinteger(vm, res); return 1; } };
 	template <> struct Return<TileIndex>    { static inline int Set(HSQUIRRELVM vm, TileIndex res)   { sq_pushinteger(vm, (int32)res.value); return 1; } };
 	template <> struct Return<bool>         { static inline int Set(HSQUIRRELVM vm, bool res)        { sq_pushbool   (vm, res); return 1; } };
-	template <> struct Return<char *>       { static inline int Set(HSQUIRRELVM vm, char *res)       { if (res == nullptr) sq_pushnull(vm); else { sq_pushstring(vm, res, -1); free(res); } return 1; } };
-	template <> struct Return<const char *> { static inline int Set(HSQUIRRELVM vm, const char *res) { if (res == nullptr) sq_pushnull(vm); else { sq_pushstring(vm, res, -1); } return 1; } };
+	template <> struct Return<char *>       { /* Do not use char *, use std::optional<std::string> instead. */ };
+	template <> struct Return<const char *> { /* Do not use const char *, use std::optional<std::string> instead. */ };
 	template <> struct Return<void *>       { static inline int Set(HSQUIRRELVM vm, void *res)       { sq_pushuserpointer(vm, res); return 1; } };
 	template <> struct Return<HSQOBJECT>    { static inline int Set(HSQUIRRELVM vm, HSQOBJECT res)   { sq_pushobject(vm, res); return 1; } };
 
+	template <> struct Return<std::optional<std::string>> {
+		static inline int Set(HSQUIRRELVM vm, std::optional<std::string> res) {
+			if (res.has_value()) {
+				sq_pushstring(vm, res.value(), -1);
+			} else {
+				sq_pushnull(vm);
+			}
+			return 1;
+		}
+	};
+
 	/**
 	 * To get a param from squirrel, we use this helper class. It converts to the right format.
 	 * We use a class instead of a plain function to allow us to use partial template specializations.