Allow GDExtensions to add editor plugins

core/extension/gdextension.cpp

@@ -677,3 +677,25 @@ String GDExtensionResourceLoader::get_resource_type(const String &p_path) const
 	}
 	return "";
 }
+
+#ifdef TOOLS_ENABLED
+Vector<StringName> GDExtensionEditorPlugins::extension_classes;
+GDExtensionEditorPlugins::EditorPluginRegisterFunc GDExtensionEditorPlugins::editor_node_add_plugin = nullptr;
+GDExtensionEditorPlugins::EditorPluginRegisterFunc GDExtensionEditorPlugins::editor_node_remove_plugin = nullptr;
+
+void GDExtensionEditorPlugins::add_extension_class(const StringName &p_class_name) {
+	if (editor_node_add_plugin) {
+		editor_node_add_plugin(p_class_name);
+	} else {
+		extension_classes.push_back(p_class_name);
+	}
+}
+
+void GDExtensionEditorPlugins::remove_extension_class(const StringName &p_class_name) {
+	if (editor_node_remove_plugin) {
+		editor_node_remove_plugin(p_class_name);
+	} else {
+		extension_classes.erase(p_class_name);
+	}
+}
+#endif // TOOLS_ENABLED

core/extension/gdextension.h

@@ -107,4 +107,28 @@ class GDExtensionResourceLoader : public ResourceFormatLoader {
 	virtual String get_resource_type(const String &p_path) const;
 };
 
+#ifdef TOOLS_ENABLED
+class GDExtensionEditorPlugins {
+private:
+	static Vector<StringName> extension_classes;
+
+protected:
+	friend class EditorNode;
+
+	// Since this in core, we can't directly reference EditorNode, so it will
+	// set these function pointers in its constructor.
+	typedef void (*EditorPluginRegisterFunc)(const StringName &p_class_name);
+	static EditorPluginRegisterFunc editor_node_add_plugin;
+	static EditorPluginRegisterFunc editor_node_remove_plugin;
+
+public:
+	static void add_extension_class(const StringName &p_class_name);
+	static void remove_extension_class(const StringName &p_class_name);
+
+	static const Vector<StringName> &get_extension_classes() {
+		return extension_classes;
+	}
+};
+#endif // TOOLS_ENABLED
+
 #endif // GDEXTENSION_H

core/extension/gdextension_interface.cpp

@@ -1058,6 +1058,20 @@ static void *gdextension_classdb_get_class_tag(GDExtensionConstStringNamePtr p_c
 	return class_info ? class_info->class_ptr : nullptr;
 }
 
+static void gdextension_editor_add_plugin(GDExtensionConstStringNamePtr p_classname) {
+#ifdef TOOLS_ENABLED
+	const StringName classname = *reinterpret_cast<const StringName *>(p_classname);
+	GDExtensionEditorPlugins::add_extension_class(classname);
+#endif
+}
+
+static void gdextension_editor_remove_plugin(GDExtensionConstStringNamePtr p_classname) {
+#ifdef TOOLS_ENABLED
+	const StringName classname = *reinterpret_cast<const StringName *>(p_classname);
+	GDExtensionEditorPlugins::remove_extension_class(classname);
+#endif
+}
+
 #define REGISTER_INTERFACE_FUNC(m_name) GDExtension::register_interface_function(#m_name, (GDExtensionInterfaceFunctionPtr)&gdextension_##m_name)
 
 void gdextension_setup_interface() {
@@ -1185,6 +1199,8 @@ void gdextension_setup_interface() {
 	REGISTER_INTERFACE_FUNC(classdb_construct_object);
 	REGISTER_INTERFACE_FUNC(classdb_get_method_bind);
 	REGISTER_INTERFACE_FUNC(classdb_get_class_tag);
+	REGISTER_INTERFACE_FUNC(editor_add_plugin);
+	REGISTER_INTERFACE_FUNC(editor_remove_plugin);
 }
 
 #undef REGISTER_INTERFACE_FUNCTION

core/extension/gdextension_interface.h

@@ -2128,6 +2128,26 @@ typedef void (*GDExtensionInterfaceClassdbUnregisterExtensionClass)(GDExtensionC
  */
 typedef void (*GDExtensionInterfaceGetLibraryPath)(GDExtensionClassLibraryPtr p_library, GDExtensionUninitializedStringPtr r_path);
 
+/**
+ * @name editor_add_plugin
+ *
+ * Adds an editor plugin.
+ *
+ * It's safe to call during initialization.
+ *
+ * @param p_class_name A pointer to a StringName with the name of a class (descending from EditorPlugin) which is already registered with ClassDB.
+ */
+typedef void (*GDExtensionInterfaceEditorAddPlugin)(GDExtensionConstStringNamePtr p_class_name);
+
+/**
+ * @name editor_remove_plugin
+ *
+ * Removes an editor plugin.
+ *
+ * @param p_class_name A pointer to a StringName with the name of a class that was previously added as an editor plugin.
+ */
+typedef void (*GDExtensionInterfaceEditorRemovePlugin)(GDExtensionConstStringNamePtr p_class_name);
+
 #ifdef __cplusplus
 }
 #endif

editor/editor_data.cpp

@@ -485,6 +485,24 @@ EditorPlugin *EditorData::get_editor_plugin(int p_idx) {
 	return editor_plugins[p_idx];
 }
 
+void EditorData::add_extension_editor_plugin(const StringName &p_class_name, EditorPlugin *p_plugin) {
+	ERR_FAIL_COND(extension_editor_plugins.has(p_class_name));
+	extension_editor_plugins.insert(p_class_name, p_plugin);
+}
+
+void EditorData::remove_extension_editor_plugin(const StringName &p_class_name) {
+	extension_editor_plugins.erase(p_class_name);
+}
+
+bool EditorData::has_extension_editor_plugin(const StringName &p_class_name) {
+	return extension_editor_plugins.has(p_class_name);
+}
+
+EditorPlugin *EditorData::get_extension_editor_plugin(const StringName &p_class_name) {
+	EditorPlugin **plugin = extension_editor_plugins.getptr(p_class_name);
+	return plugin == nullptr ? nullptr : *plugin;
+}
+
 void EditorData::add_custom_type(const String &p_type, const String &p_inherits, const Ref<Script> &p_script, const Ref<Texture2D> &p_icon) {
 	ERR_FAIL_COND_MSG(p_script.is_null(), "It's not a reference to a valid Script object.");
 	CustomType ct;

editor/editor_data.h

@@ -124,6 +124,7 @@ class EditorData {
 
 private:
 	Vector<EditorPlugin *> editor_plugins;
+	HashMap<StringName, EditorPlugin *> extension_editor_plugins;
 
 	struct PropertyData {
 		String name;
@@ -170,6 +171,11 @@ class EditorData {
 	int get_editor_plugin_count() const;
 	EditorPlugin *get_editor_plugin(int p_idx);
 
+	void add_extension_editor_plugin(const StringName &p_class_name, EditorPlugin *p_plugin);
+	void remove_extension_editor_plugin(const StringName &p_class_name);
+	bool has_extension_editor_plugin(const StringName &p_class_name);
+	EditorPlugin *get_extension_editor_plugin(const StringName &p_class_name);
+
 	void add_undo_redo_inspector_hook_callback(Callable p_callable); // Callbacks should have this signature: void (Object* undo_redo, Object *modified_object, String property, Variant new_value)
 	void remove_undo_redo_inspector_hook_callback(Callable p_callable);
 	const Vector<Callable> get_undo_redo_inspector_hook_callback();

editor/editor_interface.h

@@ -41,6 +41,7 @@ class EditorCommandPalette;
 class EditorFileSystem;
 class EditorInspector;
 class EditorPaths;
+class EditorPlugin;
 class EditorResourcePreview;
 class EditorSelection;
 class EditorSettings;
@@ -83,6 +84,9 @@ class EditorInterface : public Object {
 	void set_plugin_enabled(const String &p_plugin, bool p_enabled);
 	bool is_plugin_enabled(const String &p_plugin) const;
 
+	void add_editor_plugin(EditorPlugin *p_plugin);
+	void remove_editor_plugin(EditorPlugin *p_plugin);
+
 	// Editor GUI.
 
 	Control *get_base_control() const;

editor/editor_node.cpp

@@ -3243,6 +3243,30 @@ void EditorNode::remove_editor_plugin(EditorPlugin *p_editor, bool p_config_chan
 	}
 }
 
+void EditorNode::add_extension_editor_plugin(const StringName &p_class_name) {
+	ERR_FAIL_COND_MSG(!ClassDB::class_exists(p_class_name), vformat("No such editor plugin registered: %s", p_class_name));
+	ERR_FAIL_COND_MSG(!ClassDB::is_parent_class(p_class_name, SNAME("EditorPlugin")), vformat("Class is not an editor plugin: %s", p_class_name));
+	ERR_FAIL_COND_MSG(singleton->editor_data.has_extension_editor_plugin(p_class_name), vformat("Editor plugin already added for class: %s", p_class_name));
+
+	EditorPlugin *plugin = Object::cast_to<EditorPlugin>(ClassDB::instantiate(p_class_name));
+	singleton->editor_data.add_extension_editor_plugin(p_class_name, plugin);
+	add_editor_plugin(plugin);
+}
+
+void EditorNode::remove_extension_editor_plugin(const StringName &p_class_name) {
+	// If we're exiting, the editor plugins will get cleaned up anyway, so don't do anything.
+	if (singleton->exiting) {
+		return;
+	}
+
+	ERR_FAIL_COND_MSG(!singleton->editor_data.has_extension_editor_plugin(p_class_name), vformat("No editor plugin added for class: %s", p_class_name));
+
+	EditorPlugin *plugin = singleton->editor_data.get_extension_editor_plugin(p_class_name);
+	remove_editor_plugin(plugin);
+	memfree(plugin);
+	singleton->editor_data.remove_extension_editor_plugin(p_class_name);
+}
+
 void EditorNode::_update_addon_config() {
 	if (_initializing_plugins) {
 		return;
@@ -7769,6 +7793,12 @@ EditorNode::EditorNode() {
 		add_editor_plugin(EditorPlugins::create(i));
 	}
 
+	for (const StringName &extension_class_name : GDExtensionEditorPlugins::get_extension_classes()) {
+		add_extension_editor_plugin(extension_class_name);
+	}
+	GDExtensionEditorPlugins::editor_node_add_plugin = &EditorNode::add_extension_editor_plugin;
+	GDExtensionEditorPlugins::editor_node_remove_plugin = &EditorNode::remove_extension_editor_plugin;
+
 	for (int i = 0; i < plugin_init_callback_count; i++) {
 		plugin_init_callbacks[i]();
 	}

editor/editor_node.h

@@ -739,6 +739,9 @@ class EditorNode : public Node {
 	static void add_editor_plugin(EditorPlugin *p_editor, bool p_config_changed = false);
 	static void remove_editor_plugin(EditorPlugin *p_editor, bool p_config_changed = false);
 
+	static void add_extension_editor_plugin(const StringName &p_class_name);
+	static void remove_extension_editor_plugin(const StringName &p_class_name);
+
 	static void add_plugin_init_callback(EditorPluginInitializeCallback p_callback);
 	static void add_init_callback(EditorNodeInitCallback p_callback) { _init_callbacks.push_back(p_callback); }
 	static void add_build_callback(EditorBuildCallback p_callback);