Async-related script cleanups

15 files changed, 135 insertions, 156 deletions

diff --git a/builtin/async/init.lua b/builtin/async/init.lua
index 1b2549685..3803994d6 100644
--- a/builtin/async/init.lua
+++ b/builtin/async/init.lua
@@ -1,16 +1,10 @@
 
 core.log("info", "Initializing Asynchronous environment")
 
-function core.job_processor(serialized_func, serialized_param)
-	local func = loadstring(serialized_func)
+function core.job_processor(func, serialized_param)
 	local param = core.deserialize(serialized_param)
-	local retval = nil
 
-	if type(func) == "function" then
-		retval = core.serialize(func(param))
-	else
-		core.log("error", "ASYNC WORKER: Unable to deserialize function")
-	end
+	local retval = core.serialize(func(param))
 
 	return retval or core.serialize(nil)
 end
diff --git a/src/gui/guiEngine.cpp b/src/gui/guiEngine.cpp
index 694baf482..b3808535c 100644
--- a/src/gui/guiEngine.cpp
+++ b/src/gui/guiEngine.cpp
@@ -614,10 +614,3 @@ void GUIEngine::stopSound(s32 handle)
 {
 	m_sound_manager->stopSound(handle);
 }
-
-/******************************************************************************/
-unsigned int GUIEngine::queueAsync(const std::string &serialized_func,
-		const std::string &serialized_params)
-{
-	return m_script->queueAsync(serialized_func, serialized_params);
-}
diff --git a/src/gui/guiEngine.h b/src/gui/guiEngine.h
index 70abce181..d7e6485ef 100644
--- a/src/gui/guiEngine.h
+++ b/src/gui/guiEngine.h
@@ -175,10 +175,6 @@ public:
 		return m_scriptdir;
 	}
 
-	/** pass async callback to scriptengine **/
-	unsigned int queueAsync(const std::string &serialized_fct,
-			const std::string &serialized_params);
-
 private:
 
 	/** find and run the main menu script */
diff --git a/src/script/cpp_api/s_async.cpp b/src/script/cpp_api/s_async.cpp
index 0619b32c0..dacdcd75a 100644
--- a/src/script/cpp_api/s_async.cpp
+++ b/src/script/cpp_api/s_async.cpp
@@ -32,20 +32,19 @@ extern "C" {
 #include "filesys.h"
 #include "porting.h"
 #include "common/c_internal.h"
+#include "lua_api/l_base.h"
 
 /******************************************************************************/
 AsyncEngine::~AsyncEngine()
 {
-
 	// Request all threads to stop
 	for (AsyncWorkerThread *workerThread : workerThreads) {
 		workerThread->stop();
 	}
 
-
 	// Wake up all threads
-	for (std::vector<AsyncWorkerThread *>::iterator it = workerThreads.begin();
-			it != workerThreads.end(); ++it) {
+	for (auto it : workerThreads) {
+		(void)it;
 		jobQueueCounter.post();
 	}
 
@@ -68,6 +67,7 @@ AsyncEngine::~AsyncEngine()
 /******************************************************************************/
 void AsyncEngine::registerStateInitializer(StateInitializer func)
 {
+	FATAL_ERROR_IF(initDone, "Initializer may not be registered after init");
 	stateInitializers.push_back(func);
 }
 
@@ -85,36 +85,36 @@ void AsyncEngine::initialize(unsigned int numEngines)
 }
 
 /******************************************************************************/
-unsigned int AsyncEngine::queueAsyncJob(const std::string &func,
-		const std::string &params)
+u32 AsyncEngine::queueAsyncJob(std::string &&func, std::string &&params,
+		const std::string &mod_origin)
 {
 	jobQueueMutex.lock();
-	LuaJobInfo toAdd;
-	toAdd.id = jobIdCounter++;
-	toAdd.serializedFunction = func;
-	toAdd.serializedParams = params;
+	u32 jobId = jobIdCounter++;
 
-	jobQueue.push_back(toAdd);
+	jobQueue.emplace_back();
+	auto &to_add = jobQueue.back();
+	to_add.id = jobId;
+	to_add.function = std::move(func);
+	to_add.params = std::move(params);
+	to_add.mod_origin = mod_origin;
 
 	jobQueueCounter.post();
-
 	jobQueueMutex.unlock();
-
-	return toAdd.id;
+	return jobId;
 }
 
 /******************************************************************************/
-LuaJobInfo AsyncEngine::getJob()
+bool AsyncEngine::getJob(LuaJobInfo *job)
 {
 	jobQueueCounter.wait();
 	jobQueueMutex.lock();
 
-	LuaJobInfo retval;
+	bool retval = false;
 
 	if (!jobQueue.empty()) {
-		retval = jobQueue.front();
+		*job = std::move(jobQueue.front());
 		jobQueue.pop_front();
-		retval.valid = true;
+		retval = true;
 	}
 	jobQueueMutex.unlock();
 
@@ -122,10 +122,10 @@ LuaJobInfo AsyncEngine::getJob()
 }
 
 /******************************************************************************/
-void AsyncEngine::putJobResult(const LuaJobInfo &result)
+void AsyncEngine::putJobResult(LuaJobInfo &&result)
 {
 	resultQueueMutex.lock();
-	resultQueue.push_back(result);
+	resultQueue.emplace_back(std::move(result));
 	resultQueueMutex.unlock();
 }
 
@@ -134,26 +134,30 @@ void AsyncEngine::step(lua_State *L)
 {
 	int error_handler = PUSH_ERROR_HANDLER(L);
 	lua_getglobal(L, "core");
-	resultQueueMutex.lock();
+
+	ScriptApiBase *script = ModApiBase::getScriptApiBase(L);
+
+	MutexAutoLock autolock(resultQueueMutex);
 	while (!resultQueue.empty()) {
-		LuaJobInfo jobDone = resultQueue.front();
+		LuaJobInfo j = std::move(resultQueue.front());
 		resultQueue.pop_front();
 
 		lua_getfield(L, -1, "async_event_handler");
-
-		if (lua_isnil(L, -1)) {
+		if (lua_isnil(L, -1))
 			FATAL_ERROR("Async event handler does not exist!");
-		}
-
 		luaL_checktype(L, -1, LUA_TFUNCTION);
 
-		lua_pushinteger(L, jobDone.id);
-		lua_pushlstring(L, jobDone.serializedResult.data(),
-				jobDone.serializedResult.size());
+		lua_pushinteger(L, j.id);
+		lua_pushlstring(L, j.result.data(), j.result.size());
 
-		PCALL_RESL(L, lua_pcall(L, 2, 0, error_handler));
+		// Call handler
+		const char *origin = j.mod_origin.empty() ? nullptr : j.mod_origin.c_str();
+		script->setOriginDirect(origin);
+		int result = lua_pcall(L, 2, 0, error_handler);
+		if (result)
+			script_error(L, result, origin, "<async>");
 	}
-	resultQueueMutex.unlock();
+
 	lua_pop(L, 2); // Pop core and error handler
 }
 
@@ -168,8 +172,8 @@ void AsyncEngine::prepareEnvironment(lua_State* L, int top)
 /******************************************************************************/
 AsyncWorkerThread::AsyncWorkerThread(AsyncEngine* jobDispatcher,
 		const std::string &name) :
-	Thread(name),
 	ScriptApiBase(ScriptingType::Async),
+	Thread(name),
 	jobDispatcher(jobDispatcher)
 {
 	lua_State *L = getStack();
@@ -196,9 +200,9 @@ void* AsyncWorkerThread::run()
 {
 	lua_State *L = getStack();
 
-	std::string script = getServer()->getBuiltinLuaPath() + DIR_DELIM + "init.lua";
 	try {
-		loadScript(script);
+		loadMod(getServer()->getBuiltinLuaPath() + DIR_DELIM + "init.lua",
+			BUILTIN_MOD_NAME);
 	} catch (const ModError &e) {
 		errorstream << "Execution of async base environment failed: "
 			<< e.what() << std::endl;
@@ -213,44 +217,44 @@ void* AsyncWorkerThread::run()
 	}
 
 	// Main loop
+	LuaJobInfo j;
 	while (!stopRequested()) {
 		// Wait for job
-		LuaJobInfo toProcess = jobDispatcher->getJob();
-
-		if (!toProcess.valid || stopRequested()) {
+		if (!jobDispatcher->getJob(&j) || stopRequested())
 			continue;
-		}
 
 		lua_getfield(L, -1, "job_processor");
-		if (lua_isnil(L, -1)) {
+		if (lua_isnil(L, -1))
 			FATAL_ERROR("Unable to get async job processor!");
-		}
-
 		luaL_checktype(L, -1, LUA_TFUNCTION);
 
-		// Call it
-		lua_pushlstring(L,
-				toProcess.serializedFunction.data(),
-				toProcess.serializedFunction.size());
-		lua_pushlstring(L,
-				toProcess.serializedParams.data(),
-				toProcess.serializedParams.size());
+		if (luaL_loadbuffer(L, j.function.data(), j.function.size(), "=(async)")) {
+			errorstream << "ASYNC WORKER: Unable to deserialize function" << std::endl;
+			lua_pushnil(L);
+		}
+		lua_pushlstring(L, j.params.data(), j.params.size());
 
+		// Call it
+		setOriginDirect(j.mod_origin.empty() ? nullptr : j.mod_origin.c_str());
 		int result = lua_pcall(L, 2, 1, error_handler);
 		if (result) {
-			PCALL_RES(result);
-			toProcess.serializedResult = "";
+			try {
+				scriptError(result, "<async>");
+			} catch (const ModError &e) {
+				errorstream << e.what() << std::endl;
+			}
 		} else {
 			// Fetch result
 			size_t length;
 			const char *retval = lua_tolstring(L, -1, &length);
-			toProcess.serializedResult = std::string(retval, length);
+			j.result.assign(retval, length);
 		}
 
 		lua_pop(L, 1);  // Pop retval
 
 		// Put job result
-		jobDispatcher->putJobResult(toProcess);
+		if (!j.result.empty())
+			jobDispatcher->putJobResult(std::move(j));
 	}
 
 	lua_pop(L, 2);  // Pop core and error handler
diff --git a/src/script/cpp_api/s_async.h b/src/script/cpp_api/s_async.h
index 99a4f891c..697cb0221 100644
--- a/src/script/cpp_api/s_async.h
+++ b/src/script/cpp_api/s_async.h
@@ -21,7 +21,6 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include <vector>
 #include <deque>
-#include <map>
 
 #include "threading/semaphore.h"
 #include "threading/thread.h"
@@ -39,26 +38,29 @@ struct LuaJobInfo
 {
 	LuaJobInfo() = default;
 
-	// Function to be called in async environment
-	std::string serializedFunction = "";
-	// Parameter to be passed to function
-	std::string serializedParams = "";
-	// Result of function call
-	std::string serializedResult = "";
+	// Function to be called in async environment (from string.dump)
+	std::string function;
+	// Parameter to be passed to function (serialized)
+	std::string params;
+	// Result of function call (serialized)
+	std::string result;
+	// Name of the mod who invoked this call
+	std::string mod_origin;
 	// JobID used to identify a job and match it to callback
-	unsigned int id = 0;
-
-	bool valid = false;
+	u32 id;
 };
 
 // Asynchronous working environment
-class AsyncWorkerThread : public Thread, public ScriptApiBase {
+class AsyncWorkerThread : public Thread, virtual public ScriptApiBase {
+	friend class AsyncEngine;
 public:
-	AsyncWorkerThread(AsyncEngine* jobDispatcher, const std::string &name);
 	virtual ~AsyncWorkerThread();
 
 	void *run();
 
+protected:
+	AsyncWorkerThread(AsyncEngine* jobDispatcher, const std::string &name);
+
 private:
 	AsyncEngine *jobDispatcher = nullptr;
 };
@@ -89,7 +91,8 @@ public:
 	 * @param params Serialized parameters
 	 * @return jobid The job is queued
 	 */
-	unsigned int queueAsyncJob(const std::string &func, const std::string &params);
+	u32 queueAsyncJob(std::string &&func, std::string &&params,
+			const std::string &mod_origin = "");
 
 	/**
 	 * Engine step to process finished jobs
@@ -102,15 +105,16 @@ protected:
 	/**
 	 * Get a Job from queue to be processed
 	 *  this function blocks until a job is ready
-	 * @return a job to be processed
+	 * @param job a job to be processed
+	 * @return whether a job was available
 	 */
-	LuaJobInfo getJob();
+	bool getJob(LuaJobInfo *job);
 
 	/**
 	 * Put a Job result back to result queue
 	 * @param result result of completed job
 	 */
-	void putJobResult(const LuaJobInfo &result);
+	void putJobResult(LuaJobInfo &&result);
 
 	/**
 	 * Initialize environment with current registred functions
@@ -129,11 +133,10 @@ private:
 	std::vector<StateInitializer> stateInitializers;
 
 	// Internal counter to create job IDs
-	unsigned int jobIdCounter = 0;
+	u32 jobIdCounter = 0;
 
 	// Mutex to protect job queue
 	std::mutex jobQueueMutex;
-
 	// Job queue
 	std::deque<LuaJobInfo> jobQueue;
 
diff --git a/src/script/cpp_api/s_base.cpp b/src/script/cpp_api/s_base.cpp
index f965975a3..921f713c0 100644
--- a/src/script/cpp_api/s_base.cpp
+++ b/src/script/cpp_api/s_base.cpp
@@ -331,13 +331,9 @@ void ScriptApiBase::setOriginDirect(const char *origin)
 
 void ScriptApiBase::setOriginFromTableRaw(int index, const char *fxn)
 {
-#ifdef SCRIPTAPI_DEBUG
 	lua_State *L = getStack();
-
 	m_last_run_mod = lua_istable(L, index) ?
 		getstringfield_default(L, index, "mod_origin", "") : "";
-	//printf(">>>> running %s for mod: %s\n", fxn, m_last_run_mod.c_str());
-#endif
 }
 
 /*
diff --git a/src/script/cpp_api/s_base.h b/src/script/cpp_api/s_base.h
index 86f7f7bac..7a8ebc85a 100644
--- a/src/script/cpp_api/s_base.h
+++ b/src/script/cpp_api/s_base.h
@@ -39,7 +39,6 @@ extern "C" {
 #include "config.h"
 
 #define SCRIPTAPI_LOCK_DEBUG
-#define SCRIPTAPI_DEBUG
 
 // MUST be an invalid mod name so that mods can't
 // use that name to bypass security!
@@ -108,7 +107,9 @@ public:
 	Client* getClient();
 #endif
 
-	std::string getOrigin() { return m_last_run_mod; }
+	// IMPORTANT: these cannot be used for any security-related uses, they exist
+	// only to enrich error messages
+	const std::string &getOrigin() { return m_last_run_mod; }
 	void setOriginDirect(const char *origin);
 	void setOriginFromTableRaw(int index, const char *fxn);
 
diff --git a/src/script/cpp_api/s_security.cpp b/src/script/cpp_api/s_security.cpp
index add7b1658..580042ec2 100644
--- a/src/script/cpp_api/s_security.cpp
+++ b/src/script/cpp_api/s_security.cpp
@@ -18,7 +18,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 #include "cpp_api/s_security.h"
-
+#include "lua_api/l_base.h"
 #include "filesys.h"
 #include "porting.h"
 #include "server.h"
@@ -538,15 +538,8 @@ bool ScriptApiSecurity::checkPath(lua_State *L, const char *path,
 	if (!removed.empty())
 		abs_path += DIR_DELIM + removed;
 
-	// Get server from registry
-	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_SCRIPTAPI);
-	ScriptApiBase *script;
-#if INDIRECT_SCRIPTAPI_RIDX
-	script = (ScriptApiBase *) *(void**)(lua_touserdata(L, -1));
-#else
-	script = (ScriptApiBase *) lua_touserdata(L, -1);
-#endif
-	lua_pop(L, 1);
+	// Get gamedef from registry
+	ScriptApiBase *script = ModApiBase::getScriptApiBase(L);
 	const IGameDef *gamedef = script->getGameDef();
 	if (!gamedef)
 		return false;
@@ -669,13 +662,7 @@ int ScriptApiSecurity::sl_g_load(lua_State *L)
 int ScriptApiSecurity::sl_g_loadfile(lua_State *L)
 {
 #ifndef SERVER
-	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_SCRIPTAPI);
-#if INDIRECT_SCRIPTAPI_RIDX
-	ScriptApiBase *script = (ScriptApiBase *) *(void**)(lua_touserdata(L, -1));
-#else
-	ScriptApiBase *script = (ScriptApiBase *) lua_touserdata(L, -1);
-#endif
-	lua_pop(L, 1);
+	ScriptApiBase *script = ModApiBase::getScriptApiBase(L);
 
 	// Client implementation
 	if (script->getType() == ScriptingType::Client) {
diff --git a/src/script/lua_api/l_mainmenu.cpp b/src/script/lua_api/l_mainmenu.cpp
index ad00de1c4..6e9a5c34f 100644
--- a/src/script/lua_api/l_mainmenu.cpp
+++ b/src/script/lua_api/l_mainmenu.cpp
@@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "lua_api/l_internal.h"
 #include "common/c_content.h"
 #include "cpp_api/s_async.h"
+#include "scripting_mainmenu.h"
 #include "gui/guiEngine.h"
 #include "gui/guiMainMenu.h"
 #include "gui/guiKeyChangeMenu.h"
@@ -816,20 +817,20 @@ int ModApiMainMenu::l_open_dir(lua_State *L)
 /******************************************************************************/
 int ModApiMainMenu::l_do_async_callback(lua_State *L)
 {
-	GUIEngine* engine = getGuiEngine(L);
+	MainMenuScripting *script = getScriptApi<MainMenuScripting>(L);
 
 	size_t func_length, param_length;
 	const char* serialized_func_raw = luaL_checklstring(L, 1, &func_length);
-
 	const char* serialized_param_raw = luaL_checklstring(L, 2, &param_length);
 
 	sanity_check(serialized_func_raw != NULL);
 	sanity_check(serialized_param_raw != NULL);
 
-	std::string serialized_func = std::string(serialized_func_raw, func_length);
-	std::string serialized_param = std::string(serialized_param_raw, param_length);
+	u32 jobId = script->queueAsync(
+		std::string(serialized_func_raw, func_length),
+		std::string(serialized_param_raw, param_length));
 
-	lua_pushinteger(L, engine->queueAsync(serialized_func, serialized_param));
+	lua_pushinteger(L, jobId);
 
 	return 1;
 }
diff --git a/src/script/lua_api/l_server.cpp b/src/script/lua_api/l_server.cpp
index bf5292521..9866e0bc8 100644
--- a/src/script/lua_api/l_server.cpp
+++ b/src/script/lua_api/l_server.cpp
@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "common/c_content.h"
 #include "cpp_api/s_base.h"
 #include "cpp_api/s_security.h"
+#include "scripting_server.h"
 #include "server.h"
 #include "environment.h"
 #include "remoteplayer.h"
@@ -498,31 +499,6 @@ int ModApiServer::l_notify_authentication_modified(lua_State *L)
 	return 0;
 }
 
-// get_last_run_mod()
-int ModApiServer::l_get_last_run_mod(lua_State *L)
-{
-	NO_MAP_LOCK_REQUIRED;
-	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_CURRENT_MOD_NAME);
-	std::string current_mod = readParam<std::string>(L, -1, "");
-	if (current_mod.empty()) {
-		lua_pop(L, 1);
-		lua_pushstring(L, getScriptApiBase(L)->getOrigin().c_str());
-	}
-	return 1;
-}
-
-// set_last_run_mod(modname)
-int ModApiServer::l_set_last_run_mod(lua_State *L)
-{
-	NO_MAP_LOCK_REQUIRED;
-#ifdef SCRIPTAPI_DEBUG
-	const char *mod = lua_tostring(L, 1);
-	getScriptApiBase(L)->setOriginDirect(mod);
-	//printf(">>>> last mod set from Lua: %s\n", mod);
-#endif
-	return 0;
-}
-
 void ModApiServer::Initialize(lua_State *L, int top)
 {
 	API_FCT(request_shutdown);
@@ -555,7 +531,4 @@ void ModApiServer::Initialize(lua_State *L, int top)
 	API_FCT(remove_player);
 	API_FCT(unban_player_or_ip);
 	API_FCT(notify_authentication_modified);
-
-	API_FCT(get_last_run_mod);
-	API_FCT(set_last_run_mod);
 }
diff --git a/src/script/lua_api/l_server.h b/src/script/lua_api/l_server.h
index 2df180b17..fb7a851f4 100644
--- a/src/script/lua_api/l_server.h
+++ b/src/script/lua_api/l_server.h
@@ -103,12 +103,6 @@ private:
 	// notify_authentication_modified(name)
 	static int l_notify_authentication_modified(lua_State *L);
 
-	// get_last_run_mod()
-	static int l_get_last_run_mod(lua_State *L);
-
-	// set_last_run_mod(modname)
-	static int l_set_last_run_mod(lua_State *L);
-
 public:
 	static void Initialize(lua_State *L, int top);
 };
diff --git a/src/script/lua_api/l_util.cpp b/src/script/lua_api/l_util.cpp
index 87436fce0..9152b5f7f 100644
--- a/src/script/lua_api/l_util.cpp
+++ b/src/script/lua_api/l_util.cpp
@@ -535,6 +535,30 @@ int ModApiUtil::l_encode_png(lua_State *L)
 	return 1;
 }
 
+// get_last_run_mod()
+int ModApiUtil::l_get_last_run_mod(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+
+	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_CURRENT_MOD_NAME);
+	std::string current_mod = readParam<std::string>(L, -1, "");
+	if (current_mod.empty()) {
+		lua_pop(L, 1);
+		lua_pushstring(L, getScriptApiBase(L)->getOrigin().c_str());
+	}
+	return 1;
+}
+
+// set_last_run_mod(modname)
+int ModApiUtil::l_set_last_run_mod(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+
+	const char *mod = luaL_checkstring(L, 1);
+	getScriptApiBase(L)->setOriginDirect(mod);
+	return 0;
+}
+
 void ModApiUtil::Initialize(lua_State *L, int top)
 {
 	API_FCT(log);
@@ -574,6 +598,9 @@ void ModApiUtil::Initialize(lua_State *L, int top)
 
 	API_FCT(encode_png);
 
+	API_FCT(get_last_run_mod);
+	API_FCT(set_last_run_mod);
+
 	LuaSettings::create(L, g_settings, g_settings_path);
 	lua_setfield(L, top, "settings");
 }
@@ -629,6 +656,9 @@ void ModApiUtil::InitializeAsync(lua_State *L, int top)
 	API_FCT(colorspec_to_colorstring);
 	API_FCT(colorspec_to_bytes);
 
+	API_FCT(get_last_run_mod);
+	API_FCT(set_last_run_mod);
+
 	LuaSettings::create(L, g_settings, g_settings_path);
 	lua_setfield(L, top, "settings");
 }
diff --git a/src/script/lua_api/l_util.h b/src/script/lua_api/l_util.h
index 54d2be619..cc91e8d39 100644
--- a/src/script/lua_api/l_util.h
+++ b/src/script/lua_api/l_util.h
@@ -110,6 +110,12 @@ private:
 	// encode_png(w, h, data, level)
 	static int l_encode_png(lua_State *L);
 
+	// get_last_run_mod()
+	static int l_get_last_run_mod(lua_State *L);
+
+	// set_last_run_mod(modname)
+	static int l_set_last_run_mod(lua_State *L);
+
 public:
 	static void Initialize(lua_State *L, int top);
 	static void InitializeAsync(lua_State *L, int top);
diff --git a/src/script/scripting_mainmenu.cpp b/src/script/scripting_mainmenu.cpp
index b102a66a1..2a0cadb23 100644
--- a/src/script/scripting_mainmenu.cpp
+++ b/src/script/scripting_mainmenu.cpp
@@ -92,9 +92,9 @@ void MainMenuScripting::step()
 }
 
 /******************************************************************************/
-unsigned int MainMenuScripting::queueAsync(const std::string &serialized_func,
-		const std::string &serialized_param)
+u32 MainMenuScripting::queueAsync(std::string &&serialized_func,
+		std::string &&serialized_param)
 {
-	return asyncEngine.queueAsyncJob(serialized_func, serialized_param);
+	return asyncEngine.queueAsyncJob(std::move(serialized_func), std::move(serialized_param));
 }
 
diff --git a/src/script/scripting_mainmenu.h b/src/script/scripting_mainmenu.h
index 9e23bdc1b..3c329654a 100644
--- a/src/script/scripting_mainmenu.h
+++ b/src/script/scripting_mainmenu.h
@@ -38,8 +38,9 @@ public:
 	void step();
 
 	// Pass async events from engine to async threads
-	unsigned int queueAsync(const std::string &serialized_func,
-			const std::string &serialized_params);
+	u32 queueAsync(std::string &&serialized_func,
+		std::string &&serialized_param);
+
 private:
 	void initializeModApi(lua_State *L, int top);
 	static void registerLuaClasses(lua_State *L, int top);