Convert Space.GetBodies() to use a type filter

- Avoids pushing all bodies in Space to Lua every time we want to perform a very simple type filter operation
- Also avoids a Lua -> C -> Lua -> C call chain for each body
- Replace with lua-side filtering on a reduced set of bodies where class filter isn't granular enough
- Convert all classnames into ObjectType enum values for filtering

data/libs/SpaceStation.lua

@@ -941,7 +941,7 @@ function SpaceStation:UnlockAdvert (ref)
 end
 
 local function updateSystem ()
-	local stations = Space.GetBodies(function (b) return b.superType == "STARPORT" end)
+	local stations = Space.GetBodies("SpaceStation")
 	for i, station in ipairs(stations) do
 		-- updateStationMarket(station)
 		Economy.UpdateStationMarket(station:GetSystemBody())

data/meta/Space.lua

@@ -0,0 +1,28 @@
+-- Copyright © 2008-2023 Pioneer Developers. See AUTHORS.txt for details
+-- Licensed under the terms of the GPL v3. See licenses/GPL-3.txt
+
+-- This file implements type information about C++ classes for Lua static analysis
+
+---@meta
+
+local Space = {}
+
+package.core["Space"] = Space
+
+-- Returns a list of bodies simulated in the current system, optionally filtered by type
+---@generic T
+---@param class `T` an optional body classname to filter the returned results by
+---@return T[]
+---@overload fun(): Body[]
+function Space.GetBodies(class) end
+
+-- Returns a list of bodies at most dist away from the given body, optionally filtered by type
+---@generic T
+---@param body Body the reference body
+---@param dist number the maximum distance from the reference body to search
+---@param filter `T` an optional body classname to filter the returned results by
+---@return T[]
+---@overload fun(body: Body, dist: number): Body[]
+function Space.GetBodiesNear(body, dist, filter) end
+
+return Space

data/modules/Assassination/Assassination.lua

@@ -388,7 +388,7 @@ local onShipUndocked = function (ship, station)
 	for ref,mission in pairs(missions) do
 		if mission.status == 'ACTIVE' and
 		   mission.ship == ship then
-			planets = Space.GetBodies(function (body) return body:isa("Planet") end)
+			planets = Space.GetBodies("Planet")
 			if #planets == 0 then
 				ship:AIFlyTo(station)
 				mission.shipstate = 'outbound'

data/modules/BulkShips.lua

@@ -19,7 +19,7 @@ local spawnShips = function ()
 		return
 	end
 
-	local stations = Space.GetBodies(function (body) return body:isa("SpaceStation") and not body.isGroundStation end)
+	local stations = utils.filter_array(Space.GetBodies("SpaceStation"), function (body) return not body.isGroundStation end)
 	if #stations == 0 then
 		return
 	end

data/modules/SearchRescue/SearchRescue.lua

@@ -301,7 +301,7 @@ local triggerAdCreation = function ()
 	-- Return if ad should be created based on lawlessness and min/max frequency values.
 	-- Ad number per system is based on how many stations a system has so a player will
 	-- be met with a certain number of stations that have one or more ads.
-	local stations = Space.GetBodies(function (body) return body.superType == 'STARPORT' end)
+	local stations = Space.GetBodies("SpaceStation")
 	local freq = Game.system.lawlessness * ad_freq_max
 	if freq < ad_freq_min then freq = ad_freq_min end
 	local ad_num_max = freq * #stations
@@ -1000,10 +1000,11 @@ local findNearbyStations = function (vacuum, body)
 	-- get station bodies within current system depending on vacuum variable
 	local nearbystations_raw
 	if vacuum == true then
-		nearbystations_raw = Space.GetBodies(function (body)
-				return body.superType == 'STARPORT' and (body.type == 'STARPORT_ORBITAL' or (not body.path:GetSystemBody().parent.hasAtmosphere)) end)
+		nearbystations_raw = utils.filter_array(Space.GetBodies("SpaceStation"), function (body)
+			return body.type == 'STARPORT_ORBITAL' or (not body.path:GetSystemBody().parent.hasAtmosphere)
+		end)
 	else
-		nearbystations_raw = Space.GetBodies(function (body) return body.superType == 'STARPORT' end)
+		nearbystations_raw = Space.GetBodies("SpaceStation")
 	end
 
 	-- determine distance to body
@@ -1039,7 +1040,7 @@ local findClosestPlanets = function ()
 	end
 
 	-- get planets with stations and remove from planet list
-	local ground_stations = Space.GetBodies(function (body) return body.type == 'STARPORT_SURFACE' end)
+	local ground_stations = utils.filter_array(Space.GetBodies("SpaceStation"), function (body) return body.type == 'STARPORT_SURFACE' end)
 	for _,ground_station in pairs(ground_stations) do
 		for i=#rockyplanets, 1, -1 do
 			if rockyplanets[i] == Space.GetBody(ground_station.path:GetSystemBody().parent.index) then
@@ -1051,7 +1052,7 @@ local findClosestPlanets = function ()
 
 	-- create dictionary of stations
 	local closestplanets = {}
-	local stations = Space.GetBodies(function (body) return body.superType == 'STARPORT' end)
+	local stations = Space.GetBodies("SpaceStation")
 	for _,station in pairs(stations) do closestplanets[station] = {} end
 
 	-- pick closest planets to stations
@@ -1289,7 +1290,7 @@ local makeAdvert = function (station, manualFlavour, closestplanets)
 	local needed_fuel
 	if flavour.id == 2 or flavour.id == 5 then
 		needed_fuel = math.max(math.floor(shipdef.fuelTankMass * 0.1), 1)
-	elseif flavour.id == 4 then -- different planet 
+	elseif flavour.id == 4 then -- different planet
 		needed_fuel = math.max(math.floor(shipdef.fuelTankMass * 0.5), 1)
 	end
 	deliver_comm[Commodities.hydrogen] = needed_fuel

data/modules/System/Explore.lua

@@ -7,13 +7,14 @@ local Event = require 'Event'
 local Comms = require 'Comms'
 local Timer = require 'Timer'
 local Lang = require 'Lang'
+local utils = require 'utils'
 
 local l = Lang.GetResource("module-system")
 
 local exploreSystem = function (system)
 	Comms.Message(l.GETTING_SENSOR_DATA)
-	local starports = #Space.GetBodies(function (body) return body.superType == 'STARPORT' end)
-	local major_bodies = #Space.GetBodies(function (body) return body.superType and body.superType ~= 'STARPORT' and body.superType ~= 'NONE' end)
+	local starports = #Space.GetBodies("SpaceStation")
+	local major_bodies = #Space.GetBodies("TerrainBody")
 	local bodies
 	if major_bodies == 1 then
 		bodies = l.BODY

data/modules/TradeShips/Debug.lua

@@ -108,7 +108,7 @@ debugView.registerTab('debug-trade-ships', function()
 			ui.sameLine()
 			property("Lawlessness", string.format("%.4f", Game.system.lawlessness))
 			ui.sameLine()
-			property("Total bodies in space", #Space.GetBodies())
+			property("Total bodies in space", Space.GetNumBodies())
 		end
 
 		if ui.collapsingHeader("Stations") then

data/modules/TradeShips/Flow.lua

@@ -108,7 +108,7 @@ Flow.calculateSystemParams = function()
 	if system.population == 0 then return nil end
 
 	-- all ports in the system
-	local ports = Space.GetBodies(function (body) return body.superType == 'STARPORT' end)
+	local ports = Space.GetBodies("SpaceStation")
 	-- check if the current system can be traded in
 	if #ports == 0 then return nil end
 

src/lua/LuaBody.cpp

@@ -37,7 +37,20 @@ namespace PiGui {
 	extern int pushOnScreenPositionDirection(lua_State *l, vector3d position);
 } // namespace PiGui
 
-static LuaFlags<ObjectType> s_bodyFlags(ENUM_PhysicsObjectType);
+static LuaFlags<ObjectType> s_bodyFlags ({
+	{ "Body", ObjectType::BODY },
+	{ "ModelBody", ObjectType::MODELBODY },
+	{ "Ship", ObjectType::SHIP },
+	{ "Player", ObjectType::PLAYER },
+	{ "SpaceStation", ObjectType::SPACESTATION },
+	{ "TerrainBody", ObjectType::TERRAINBODY },
+	{ "Planet", ObjectType::PLANET },
+	{ "Star", ObjectType::STAR },
+	{ "CargoBody", ObjectType::CARGOBODY },
+	{ "Projectile", ObjectType::PROJECTILE },
+	{ "Missile", ObjectType::MISSILE },
+	{ "HyperspaceCloud", ObjectType::HYPERSPACECLOUD }
+});
 
 /*
  * Class: Body
@@ -902,4 +915,6 @@ void LuaObject<Body>::RegisterClass()
 	LuaObjectBase::RegisterSerializer("CargoBody", body_serializers);
 	LuaObjectBase::RegisterSerializer("Missile", body_serializers);
 	LuaObjectBase::RegisterSerializer("HyperspaceCloud", body_serializers);
+
+	s_bodyFlags.Register(Lua::manager->GetLuaState(), "Constants.ObjectType");
 }

src/lua/LuaSpace.cpp

@@ -905,21 +905,46 @@ static int l_space_get_body(lua_State *l)
 	return 1;
 }
 
+/*
+ * Function: GetNumBodies
+ *
+ * Get the total number of bodies simulated in the current Space
+ *
+ * bodies = #Space.GetNumBodies()
+ *
+ * Return:
+ *
+ *   num - the number of bodies currently existing in Space
+ *
+ * Availability:
+ *
+ *   Oct. 2023
+ *
+ * Status:
+ *
+ *   stable
+ */
+static int l_space_get_num_bodies(lua_State *l)
+{
+	if (!Pi::game) {
+		return luaL_error(l, "Game is not started!");
+	}
+
+	LuaPush(l, Pi::game->GetSpace()->GetNumBodies());
+	return 1;
+}
+
 /*
  * Function: GetBodies
  *
- * Get all the <Body> objects that match the specified filter
+ * Get all the <Body> objects that match the specified filter type
  *
- * bodies = Space.GetBodies(filter)
+ * bodies = Space.GetBodies([type])
  *
  * Parameters:
  *
- *   filter - an option function. If specificed the function will be called
- *            once for each body with the <Body> object as the only parameter.
- *            If the filter function returns true then the <Body> will be
- *            included in the array returned by <GetBodies>, otherwise it will
- *            be omitted. If no filter function is specified then all bodies
- *            are returned.
+ *   type - an optional Body classname acting as a filter on the type of the
+ *          returned bodies
  *
  * Return:
  *
@@ -929,13 +954,13 @@ static int l_space_get_body(lua_State *l)
  * Example:
  *
  * > -- get all the ground-based stations
- * > local stations = Space.GetBodies(function (body)
+ * > local stations = utils.filter_array(Space.GetBodies("SpaceStation"), function(body)
  * >     return body.type == "STARPORT_SURFACE"
  * > end)
  *
  * Availability:
  *
- *   alpha 10
+ *   Oct. 2023
  *
  * Status:
  *
@@ -950,35 +975,15 @@ static int l_space_get_bodies(lua_State *l)
 
 	LUA_DEBUG_START(l);
 
-	bool filter = false;
-	if (lua_gettop(l) >= 1) {
-		luaL_checktype(l, 1, LUA_TFUNCTION); // any type of function
-		filter = true;
-	}
+	ObjectType filterBodyType = LuaPull<ObjectType>(l, 1, ObjectType::BODY);
+	bool filter = filterBodyType != ObjectType::BODY;
 
 	lua_newtable(l);
 
 	int idx = 1;
 	for (Body *b : Pi::game->GetSpace()->GetBodies()) {
-		if (filter) {
-			lua_pushvalue(l, 1);
-			LuaObject<Body>::PushToLua(b);
-			if (int ret = lua_pcall(l, 1, 1, 0)) {
-				const char *errmsg("Unknown error");
-				if (ret == LUA_ERRRUN)
-					errmsg = lua_tostring(l, -1);
-				else if (ret == LUA_ERRMEM)
-					errmsg = "memory allocation failure";
-				else if (ret == LUA_ERRERR)
-					errmsg = "error in error handler function";
-				luaL_error(l, "Error in filter function: %s", errmsg);
-			}
-			if (!lua_toboolean(l, -1)) {
-				lua_pop(l, 1);
-				continue;
-			}
-			lua_pop(l, 1);
-		}
+		if (filter && !b->IsType(filterBodyType))
+			continue;
 
 		lua_pushinteger(l, idx++);
 		LuaObject<Body>::PushToLua(b);
@@ -1110,6 +1115,7 @@ void LuaSpace::Register()
 		{ "PutShipOnRoute", l_space_put_ship_on_route },
 
 		{ "GetBody", l_space_get_body },
+		{ "GetNumBodies", l_space_get_num_bodies },
 		{ "GetBodies", l_space_get_bodies },
 		{ "GetBodiesNear", l_space_get_bodies_near },