Merge pull request #52084 from reduz/engine-singleton-register

Add ability to register singletons from Engine API

core/config/engine.cpp

@@ -199,17 +199,41 @@ bool Engine::is_printing_error_messages() const {
 }
 
 void Engine::add_singleton(const Singleton &p_singleton) {
+	ERR_FAIL_COND_MSG(singleton_ptrs.has(p_singleton.name), "Can't register singleton that already exists: " + String(p_singleton.name));
 	singletons.push_back(p_singleton);
 	singleton_ptrs[p_singleton.name] = p_singleton.ptr;
 }
 
-Object *Engine::get_singleton_object(const String &p_name) const {
+Object *Engine::get_singleton_object(const StringName &p_name) const {
 	const Map<StringName, Object *>::Element *E = singleton_ptrs.find(p_name);
-	ERR_FAIL_COND_V_MSG(!E, nullptr, "Failed to retrieve non-existent singleton '" + p_name + "'.");
+	ERR_FAIL_COND_V_MSG(!E, nullptr, "Failed to retrieve non-existent singleton '" + String(p_name) + "'.");
 	return E->get();
 }
 
-bool Engine::has_singleton(const String &p_name) const {
+bool Engine::is_singleton_user_created(const StringName &p_name) const {
+	ERR_FAIL_COND_V(!singleton_ptrs.has(p_name), false);
+
+	for (const Singleton &E : singletons) {
+		if (E.name == p_name && E.user_created) {
+			return true;
+		}
+	}
+
+	return false;
+}
+void Engine::remove_singleton(const StringName &p_name) {
+	ERR_FAIL_COND(!singleton_ptrs.has(p_name));
+
+	for (List<Singleton>::Element *E = singletons.front(); E; E = E->next()) {
+		if (E->get().name == p_name) {
+			singletons.erase(E);
+			singleton_ptrs.erase(p_name);
+			return;
+		}
+	}
+}
+
+bool Engine::has_singleton(const StringName &p_name) const {
 	return singleton_ptrs.has(p_name);
 }
 

core/config/engine.h

@@ -42,6 +42,7 @@ public:
 		StringName name;
 		Object *ptr;
 		StringName class_name; //used for binding generation hinting
+		bool user_created = false;
 		Singleton(const StringName &p_name = StringName(), Object *p_ptr = nullptr, const StringName &p_class_name = StringName());
 	};
 
@@ -109,8 +110,10 @@ public:
 
 	void add_singleton(const Singleton &p_singleton);
 	void get_singletons(List<Singleton> *p_singletons);
-	bool has_singleton(const String &p_name) const;
-	Object *get_singleton_object(const String &p_name) const;
+	bool has_singleton(const StringName &p_name) const;
+	Object *get_singleton_object(const StringName &p_name) const;
+	void remove_singleton(const StringName &p_name);
+	bool is_singleton_user_created(const StringName &p_name) const;
 
 #ifdef TOOLS_ENABLED
 	_FORCE_INLINE_ void set_editor_hint(bool p_enabled) { editor_hint = p_enabled; }

core/core_bind.cpp

@@ -2165,14 +2165,41 @@ bool Engine::is_in_physics_frame() const {
 	return ::Engine::get_singleton()->is_in_physics_frame();
 }
 
-bool Engine::has_singleton(const String &p_name) const {
+bool Engine::has_singleton(const StringName &p_name) const {
 	return ::Engine::get_singleton()->has_singleton(p_name);
 }
 
-Object *Engine::get_singleton_object(const String &p_name) const {
+Object *Engine::get_singleton_object(const StringName &p_name) const {
 	return ::Engine::get_singleton()->get_singleton_object(p_name);
 }
 
+void Engine::register_singleton(const StringName &p_name, Object *p_object) {
+	ERR_FAIL_COND_MSG(has_singleton(p_name), "Singleton already registered: " + String(p_name));
+	ERR_FAIL_COND_MSG(p_name.operator String().is_valid_identifier(), "Singleton name is not a valid identifier: " + String(p_name));
+	::Engine::Singleton s;
+	s.class_name = p_name;
+	s.name = p_name;
+	s.ptr = p_object;
+	s.user_created = true;
+	::Engine::get_singleton()->add_singleton(s);
+	;
+}
+void Engine::unregister_singleton(const StringName &p_name) {
+	ERR_FAIL_COND_MSG(!has_singleton(p_name), "Attempt to remove unregisteres singleton: " + String(p_name));
+	ERR_FAIL_COND_MSG(!::Engine::get_singleton()->is_singleton_user_created(p_name), "Attempt to remove non-user created singleton: " + String(p_name));
+	::Engine::get_singleton()->remove_singleton(p_name);
+}
+
+Vector<String> Engine::get_singleton_list() const {
+	List<::Engine::Singleton> singletons;
+	::Engine::get_singleton()->get_singletons(&singletons);
+	Vector<String> ret;
+	for (List<::Engine::Singleton>::Element *E = singletons.front(); E; E = E->next()) {
+		ret.push_back(E->get().name);
+	}
+	return ret;
+}
+
 void Engine::set_editor_hint(bool p_enabled) {
 	::Engine::get_singleton()->set_editor_hint(p_enabled);
 }
@@ -2220,6 +2247,10 @@ void Engine::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("has_singleton", "name"), &Engine::has_singleton);
 	ClassDB::bind_method(D_METHOD("get_singleton", "name"), &Engine::get_singleton_object);
 
+	ClassDB::bind_method(D_METHOD("register_singleton", "name", "instance"), &Engine::register_singleton);
+	ClassDB::bind_method(D_METHOD("unregister_singleton", "name"), &Engine::unregister_singleton);
+	ClassDB::bind_method(D_METHOD("get_singleton_list"), &Engine::get_singleton_list);
+
 	ClassDB::bind_method(D_METHOD("set_editor_hint", "enabled"), &Engine::set_editor_hint);
 	ClassDB::bind_method(D_METHOD("is_editor_hint"), &Engine::is_editor_hint);
 

core/core_bind.h

@@ -639,8 +639,11 @@ public:
 
 	bool is_in_physics_frame() const;
 
-	bool has_singleton(const String &p_name) const;
-	Object *get_singleton_object(const String &p_name) const;
+	bool has_singleton(const StringName &p_name) const;
+	Object *get_singleton_object(const StringName &p_name) const;
+	void register_singleton(const StringName &p_name, Object *p_object);
+	void unregister_singleton(const StringName &p_name);
+	Vector<String> get_singleton_list() const;
 
 	void set_editor_hint(bool p_enabled);
 	bool is_editor_hint() const;

doc/classes/Engine.xml

@@ -84,11 +84,16 @@
 		</method>
 		<method name="get_singleton" qualifiers="const">
 			<return type="Object" />
-			<argument index="0" name="name" type="String" />
+			<argument index="0" name="name" type="StringName" />
 			<description>
 				Returns a global singleton with given [code]name[/code]. Often used for plugins, e.g. GodotPayments.
 			</description>
 		</method>
+		<method name="get_singleton_list" qualifiers="const">
+			<return type="PackedStringArray" />
+			<description>
+			</description>
+		</method>
 		<method name="get_version_info" qualifiers="const">
 			<return type="Dictionary" />
 			<description>
@@ -125,7 +130,7 @@
 		</method>
 		<method name="has_singleton" qualifiers="const">
 			<return type="bool" />
-			<argument index="0" name="name" type="String" />
+			<argument index="0" name="name" type="StringName" />
 			<description>
 				Returns [code]true[/code] if a singleton with given [code]name[/code] exists in global scope.
 			</description>
@@ -136,6 +141,19 @@
 				Returns [code]true[/code] if the game is inside the fixed process and physics phase of the game loop.
 			</description>
 		</method>
+		<method name="register_singleton">
+			<return type="void" />
+			<argument index="0" name="name" type="StringName" />
+			<argument index="1" name="instance" type="Object" />
+			<description>
+			</description>
+		</method>
+		<method name="unregister_singleton">
+			<return type="void" />
+			<argument index="0" name="name" type="StringName" />
+			<description>
+			</description>
+		</method>
 	</methods>
 	<members>
 		<member name="editor_hint" type="bool" setter="set_editor_hint" getter="is_editor_hint" default="true">