Add API to cancel async jobs (#14602)

* Implement API to cancel async jobs

Co-authored-by: sfan5 <sfan5@live.de>

* update AsyncJob:cancel documentation from review

* Use IPC to unblock async

* review

* review async unblocking

* review

* Apply suggestions from code review

Co-authored-by: sfan5 <sfan5@live.de>

* minor licensing

---------

Co-authored-by: y5nw <y5nw@protonmail.com>
Co-authored-by: sfan5 <sfan5@live.de>

src/script/lua_api/CMakeLists.txt

@@ -3,6 +3,7 @@ file(GLOB common_SCRIPT_LUA_API_HDRS "${CMAKE_CURRENT_SOURCE_DIR}/*.h")
 set(common_SCRIPT_LUA_API_SRCS
 	${common_SCRIPT_LUA_API_HDRS}
 	${CMAKE_CURRENT_SOURCE_DIR}/l_areastore.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/l_async.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/l_auth.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/l_base.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/l_craft.cpp

src/script/lua_api/l_async.cpp

@@ -0,0 +1,64 @@
+// Luanti
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "lua_api/l_internal.h"
+#include "lua_api/l_async.h"
+#include "cpp_api/s_async.h"
+
+static std::string get_serialized_function(lua_State *L, int index)
+{
+	luaL_checktype(L, index, LUA_TFUNCTION);
+	call_string_dump(L, index);
+	size_t func_length;
+	const char *serialized_func_raw = lua_tolstring(L, -1, &func_length);
+	std::string serialized_func(serialized_func_raw, func_length);
+	lua_pop(L, 1);
+	return serialized_func;
+}
+
+// do_async_callback(func, params, mod_origin)
+int ModApiAsync::l_do_async_callback(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+	ScriptApiAsync *script = getScriptApi<ScriptApiAsync>(L);
+
+	luaL_checktype(L, 2, LUA_TTABLE);
+	luaL_checktype(L, 3, LUA_TSTRING);
+
+	auto serialized_func = get_serialized_function(L, 1);
+	PackedValue *param = script_pack(L, 2);
+	std::string mod_origin = readParam<std::string>(L, 3);
+
+	u32 jobId = script->queueAsync(
+		std::move(serialized_func),
+		param, mod_origin);
+
+	lua_pushinteger(L, jobId);
+	return 1;
+}
+
+// cancel_async_callback(id)
+int ModApiAsync::l_cancel_async_callback(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+	ScriptApiAsync *script = getScriptApi<ScriptApiAsync>(L);
+	u32 id = luaL_checkinteger(L, 1);
+	lua_pushboolean(L, script->cancelAsync(id));
+	return 1;
+}
+
+// get_async_capacity()
+int ModApiAsync::l_get_async_threading_capacity(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+	ScriptApiAsync *script = getScriptApi<ScriptApiAsync>(L);
+	lua_pushinteger(L, script->getThreadingCapacity());
+	return 1;
+}
+
+void ModApiAsync::Initialize(lua_State *L, int top)
+{
+	API_FCT(do_async_callback);
+	API_FCT(cancel_async_callback);
+	API_FCT(get_async_threading_capacity);
+}

src/script/lua_api/l_async.h

@@ -0,0 +1,19 @@
+// Luanti
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#pragma once
+
+#include "lua_api/l_base.h"
+
+class ModApiAsync : public ModApiBase
+{
+public:
+	static void Initialize(lua_State *L, int top);
+private:
+	// do_async_callback(func, params, mod_origin)
+	static int l_do_async_callback(lua_State *L);
+	// cancel_async_callback(id)
+	static int l_cancel_async_callback(lua_State *L);
+	// get_async_threading_capacity()
+	static int l_get_async_threading_capacity(lua_State *L);
+};

src/script/lua_api/l_server.cpp

@@ -625,33 +625,6 @@ int ModApiServer::l_notify_authentication_modified(lua_State *L)
 	return 0;
 }
 
-// do_async_callback(func, params, mod_origin)
-int ModApiServer::l_do_async_callback(lua_State *L)
-{
-	NO_MAP_LOCK_REQUIRED;
-	ServerScripting *script = getScriptApi<ServerScripting>(L);
-
-	luaL_checktype(L, 1, LUA_TFUNCTION);
-	luaL_checktype(L, 2, LUA_TTABLE);
-	luaL_checktype(L, 3, LUA_TSTRING);
-
-	call_string_dump(L, 1);
-	size_t func_length;
-	const char *serialized_func_raw = lua_tolstring(L, -1, &func_length);
-
-	PackedValue *param = script_pack(L, 2);
-
-	std::string mod_origin = readParam<std::string>(L, 3);
-
-	u32 jobId = script->queueAsync(
-		std::string(serialized_func_raw, func_length),
-		param, mod_origin);
-
-	lua_settop(L, 0);
-	lua_pushinteger(L, jobId);
-	return 1;
-}
-
 // register_async_dofile(path)
 int ModApiServer::l_register_async_dofile(lua_State *L)
 {
@@ -747,7 +720,6 @@ void ModApiServer::Initialize(lua_State *L, int top)
 	API_FCT(unban_player_or_ip);
 	API_FCT(notify_authentication_modified);
 
-	API_FCT(do_async_callback);
 	API_FCT(register_async_dofile);
 	API_FCT(serialize_roundtrip);
 

src/script/lua_api/l_server.h

@@ -100,9 +100,6 @@ private:
 	// notify_authentication_modified(name)
 	static int l_notify_authentication_modified(lua_State *L);
 
-	// do_async_callback(func, params, mod_origin)
-	static int l_do_async_callback(lua_State *L);
-
 	// register_async_dofile(path)
 	static int l_register_async_dofile(lua_State *L);