Adopt EventEmitter class instead of injecting Signal methods

Introduce a new class, EventEmitter, which implements signal
handling for pure JavaScript classes. EventEmitter still
utilizes GJS' addSignalMethods internally.

EventEmitter allows static typechecking to understand the
structure of event-emitting JS classes and makes creating
child classes simpler.

The name 'EventEmitter' mirrors a common name for this pattern
in Node and in JS libraries.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2043>

js/gdm/batch.js

@@ -43,12 +43,15 @@
  * are not used elsewhere. These APIs may ultimately get dropped entirely and
  * replaced by something else.
  */
+/* exported ConcurrentBatch, ConsecutiveBatch */
 
 const { GObject } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
-var Task = class {
+var Task = class extends Signals.EventEmitter {
     constructor(scope, handler) {
+        super();
+
         if (scope)
             this.scope = scope;
         else
@@ -64,7 +67,6 @@ var Task = class {
         return null;
     }
 };
-Signals.addSignalMethods(Task.prototype);
 
 var Hold = class extends Task {
     constructor() {
@@ -101,7 +103,6 @@ var Hold = class extends Task {
         return this._acquisitions > 0;
     }
 };
-Signals.addSignalMethods(Hold.prototype);
 
 var Batch = class extends Task {
     constructor(scope, tasks) {
@@ -171,7 +172,6 @@ var Batch = class extends Task {
         this.tasks = this.tasks.splice(0, this._currentTaskIndex + 1);
     }
 };
-Signals.addSignalMethods(Batch.prototype);
 
 var ConcurrentBatch = class extends Batch {
     process() {
@@ -186,7 +186,6 @@ var ConcurrentBatch = class extends Batch {
         this.nextTask();
     }
 };
-Signals.addSignalMethods(ConcurrentBatch.prototype);
 
 var ConsecutiveBatch = class extends Batch {
     process() {
@@ -205,4 +204,3 @@ var ConsecutiveBatch = class extends Batch {
         }
     }
 };
-Signals.addSignalMethods(ConsecutiveBatch.prototype);

js/gdm/credentialManager.js

@@ -1,8 +1,12 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 /* exported CredentialManager */
 
-var CredentialManager = class CredentialManager {
+const Signals = imports.misc.signals;
+
+var CredentialManager = class CredentialManager extends Signals.EventEmitter {
     constructor(service) {
+        super();
+
         this._token = null;
         this._service = service;
         this._authenticatedSignalId = null;

js/gdm/oVirt.js

@@ -2,7 +2,6 @@
 /* exported getOVirtCredentialsManager */
 
 const Gio = imports.gi.Gio;
-const Signals = imports.signals;
 const Credential = imports.gdm.credentialManager;
 
 var SERVICE_NAME = 'gdm-ovirtcred';
@@ -43,7 +42,6 @@ var OVirtCredentialsManager = class OVirtCredentialsManager extends Credential.C
             });
     }
 };
-Signals.addSignalMethods(OVirtCredentialsManager.prototype);
 
 function getOVirtCredentialsManager() {
     if (!_oVirtCredentialsManager)

js/gdm/realmd.js

@@ -1,7 +1,8 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/* exported Manager */
 
 const Gio = imports.gi.Gio;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const { loadInterfaceXML } = imports.misc.fileUtils;
 
@@ -14,8 +15,10 @@ const Service = Gio.DBusProxy.makeProxyWrapper(ServiceIface);
 const RealmIface = loadInterfaceXML("org.freedesktop.realmd.Realm");
 const Realm = Gio.DBusProxy.makeProxyWrapper(RealmIface);
 
-var Manager = class {
+var Manager = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._aggregateProvider = Provider(Gio.DBus.system,
                                            'org.freedesktop.realmd',
                                            '/org/freedesktop/realmd',
@@ -105,4 +108,3 @@ var Manager = class {
         this._updateLoginFormat();
     }
 };
-Signals.addSignalMethods(Manager.prototype);

js/gdm/util.js

@@ -1,9 +1,10 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 /* exported BANNER_MESSAGE_KEY, BANNER_MESSAGE_TEXT_KEY, LOGO_KEY,
-            DISABLE_USER_LIST_KEY, fadeInActor, fadeOutActor, cloneAndFadeOutActor */
+            DISABLE_USER_LIST_KEY, fadeInActor, fadeOutActor, cloneAndFadeOutActor,
+            ShellUserVerifier */
 
 const { Clutter, Gdm, Gio, GLib } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Batch = imports.gdm.batch;
 const OVirt = imports.gdm.oVirt;
@@ -135,8 +136,9 @@ function cloneAndFadeOutActor(actor) {
     return hold;
 }
 
-var ShellUserVerifier = class {
+var ShellUserVerifier = class extends Signals.EventEmitter {
     constructor(client, params) {
+        super();
         params = Params.parse(params, { reauthenticationOnly: false });
         this._reauthOnly = params.reauthenticationOnly;
 
@@ -783,4 +785,3 @@ var ShellUserVerifier = class {
         this._verificationFailed(serviceName, true);
     }
 };
-Signals.addSignalMethods(ShellUserVerifier.prototype);

js/gdm/vmware.js

@@ -2,7 +2,6 @@
 /* exported getVmwareCredentialsManager */
 
 const Gio = imports.gi.Gio;
-const Signals = imports.signals;
 const Credential = imports.gdm.credentialManager;
 
 const dbusPath = '/org/vmware/viewagent/Credentials';
@@ -46,7 +45,6 @@ var VmwareCredentialsManager = class VmwareCredentialsManager extends Credential
             });
     }
 };
-Signals.addSignalMethods(VmwareCredentialsManager.prototype);
 
 function getVmwareCredentialsManager() {
     if (!_vmwareCredentialsManager)

js/js-resources.gresource.xml

@@ -29,6 +29,7 @@
     <file>misc/permissionStore.js</file>
     <file>misc/signalTracker.js</file>
     <file>misc/smartcardManager.js</file>
+    <file>misc/signals.js</file>
     <file>misc/systemActions.js</file>
     <file>misc/util.js</file>
     <file>misc/weather.js</file>

js/misc/history.js

@@ -1,13 +1,16 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/* exported HistoryManager */
 
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 const Clutter = imports.gi.Clutter;
 const Params = imports.misc.params;
 
 var DEFAULT_LIMIT = 512;
 
-var HistoryManager = class {
+var HistoryManager = class extends Signals.EventEmitter {
     constructor(params) {
+        super();
+
         params = Params.parse(params, {
             gsettingsKey: null,
             limit: DEFAULT_LIMIT,
@@ -109,4 +112,3 @@ var HistoryManager = class {
             global.settings.set_strv(this._key, this._history);
     }
 };
-Signals.addSignalMethods(HistoryManager.prototype);

js/misc/ibusManager.js

@@ -2,7 +2,7 @@
 /* exported getIBusManager */
 
 const { Gio, GLib, IBus, Meta, Shell } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const IBusCandidatePopup = imports.ui.ibusCandidatePopup;
 
@@ -40,8 +40,10 @@ function getIBusManager() {
     return _ibusManager;
 }
 
-var IBusManager = class {
+var IBusManager = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         IBus.init();
 
         // This is the longest we'll keep the keyboard frozen until an input
@@ -325,4 +327,3 @@ var IBusManager = class {
                 });
     }
 };
-Signals.addSignalMethods(IBusManager.prototype);

js/misc/loginManager.js

@@ -2,7 +2,7 @@
 /* exported canLock, getLoginManager, registerSessionWithGDM */
 
 const { GLib, Gio } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const { loadInterfaceXML } = imports.misc.fileUtils;
 
@@ -87,8 +87,10 @@ function getLoginManager() {
     return _loginManager;
 }
 
-var LoginManagerSystemd = class {
+var LoginManagerSystemd = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._proxy = new SystemdLoginManager(Gio.DBus.system,
                                               'org.freedesktop.login1',
                                               '/org/freedesktop/login1');
@@ -202,9 +204,8 @@ var LoginManagerSystemd = class {
         this.emit('prepare-for-sleep', aboutToSuspend);
     }
 };
-Signals.addSignalMethods(LoginManagerSystemd.prototype);
 
-var LoginManagerDummy = class {
+var LoginManagerDummy = class extends Signals.EventEmitter  {
     getCurrentSessionProxy(_callback) {
         // we could return a DummySession object that fakes whatever callers
         // expect (at the time of writing: connect() and connectSignal()
@@ -236,4 +237,3 @@ var LoginManagerDummy = class {
         return null;
     }
 };
-Signals.addSignalMethods(LoginManagerDummy.prototype);

js/misc/objectManager.js

@@ -1,8 +1,9 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/* exported ObjectManager */
 
 const { Gio, GLib } = imports.gi;
 const Params = imports.misc.params;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 // Specified in the D-Bus specification here:
 // http://dbus.freedesktop.org/doc/dbus-specification.html#standard-interfaces-objectmanager
@@ -25,8 +26,10 @@ const ObjectManagerIface = `
 
 const ObjectManagerInfo = Gio.DBusInterfaceInfo.new_for_xml(ObjectManagerIface);
 
-var ObjectManager = class {
+var ObjectManager = class extends Signals.EventEmitter {
     constructor(params) {
+        super();
+
         params = Params.parse(params, {
             connection: null,
             name: null,
@@ -288,4 +291,3 @@ var ObjectManager = class {
         return proxies;
     }
 };
-Signals.addSignalMethods(ObjectManager.prototype);

js/misc/signalTracker.js

@@ -1,4 +1,4 @@
-/* exported TransientSignalHolder, addObjectSignalMethods */
+/* exported TransientSignalHolder, connectObject, disconnectObject */
 const { GObject } = imports.gi;
 
 const destroyableTypes = [];
@@ -214,25 +214,6 @@ function disconnectObject(thisObj, obj) {
     SignalManager.getDefault().getSignalTracker(thisObj).untrack(obj);
 }
 
-/**
- * Add connectObject()/disconnectObject() methods
- * to prototype. The prototype must have the connect()
- * and disconnect() signal methods.
- *
- * @param {prototype} proto - a prototype
- */
-function addObjectSignalMethods(proto) {
-    proto['connectObject'] = function (...args) {
-        connectObject(this, ...args);
-    };
-    proto['connect_object'] = proto['connectObject'];
-
-    proto['disconnectObject'] = function (obj) {
-        disconnectObject(this, obj);
-    };
-    proto['disconnect_object'] = proto['disconnectObject'];
-}
-
 /**
  * Register a GObject type as having a 'destroy' signal
  * that should disconnect all handlers

js/misc/signals.js

@@ -0,0 +1,22 @@
+const Signals = imports.signals;
+const SignalTracker = imports.misc.signalTracker;
+
+var EventEmitter = class EventEmitter {
+    connectObject(...args) {
+        return SignalTracker.connectObject(this, ...args);
+    }
+
+    disconnectObject(...args) {
+        return SignalTracker.disconnectObject(this, ...args);
+    }
+
+    connect_object(...args) {
+        return this.connectObject(...args);
+    }
+
+    disconnect_object(...args) {
+        return this.disconnectObject(...args);
+    }
+};
+
+Signals.addSignalMethods(EventEmitter.prototype);

js/misc/smartcardManager.js

@@ -2,7 +2,7 @@
 /* exported getSmartcardManager */
 
 const Gio = imports.gi.Gio;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const ObjectManager = imports.misc.objectManager;
 
@@ -25,8 +25,10 @@ function getSmartcardManager() {
     return _smartcardManager;
 }
 
-var SmartcardManager = class {
+var SmartcardManager = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._objectManager = new ObjectManager.ObjectManager({
             connection: Gio.DBus.session,
             name: 'org.gnome.SettingsDaemon.Smartcard',
@@ -114,4 +116,3 @@ var SmartcardManager = class {
         return true;
     }
 };
-Signals.addSignalMethods(SmartcardManager.prototype);

js/misc/weather.js

@@ -1,7 +1,8 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/* exported WeatherClient */
 
 const { Geoclue, Gio, GLib, GWeather, Shell } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const PermissionStore = imports.misc.permissionStore;
 
@@ -20,8 +21,10 @@ const WEATHER_APP_ID = 'org.gnome.Weather.desktop';
 // Minimum time between updates to show loading indication
 var UPDATE_THRESHOLD = 10 * GLib.TIME_SPAN_MINUTE;
 
-var WeatherClient = class {
+var WeatherClient = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._loading = false;
         this._locationValid = false;
         this._lastUpdate = GLib.DateTime.new_from_unix_local(0);
@@ -319,4 +322,3 @@ var WeatherClient = class {
         this._updateAutoLocation();
     }
 };
-Signals.addSignalMethods(WeatherClient.prototype);

js/ui/appFavorites.js

@@ -3,7 +3,7 @@
 
 const Shell = imports.gi.Shell;
 const ParentalControlsManager = imports.misc.parentalControlsManager;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Main = imports.ui.main;
 
@@ -64,8 +64,10 @@ const RENAMED_DESKTOP_IDS = {
     'evince.desktop': 'org.gnome.Evince.desktop',
 };
 
-class AppFavorites {
+class AppFavorites extends Signals.EventEmitter {
     constructor() {
+        super();
+
         // Filter the apps through the user’s parental controls.
         this._parentalControlsManager = ParentalControlsManager.getDefault();
         this._parentalControlsManager.connect('app-filter-changed', () => {
@@ -201,7 +203,6 @@ class AppFavorites {
         });
     }
 }
-Signals.addSignalMethods(AppFavorites.prototype);
 
 var appFavoritesInstance = null;
 function getAppFavorites() {

js/ui/background.js

@@ -1,5 +1,5 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
-/* exported SystemBackground */
+/* exported SystemBackground, BackgroundManager */
 
 // READ THIS FIRST
 // Background handling is a maze of objects, both objects in this file, and
@@ -95,7 +95,7 @@
 //     MetaBackgroundImage         MetaBackgroundImage
 
 const { Clutter, GDesktopEnums, Gio, GLib, GObject, GnomeDesktop, Meta } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const LoginManager = imports.misc.loginManager;
 const Main = imports.ui.main;
@@ -137,8 +137,10 @@ function _fileEqual0(file1, file2) {
     return file1.equal(file2);
 }
 
-var BackgroundCache = class BackgroundCache {
+var BackgroundCache = class BackgroundCache extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._fileMonitors = {};
         this._backgroundSources = {};
         this._animations = {};
@@ -221,7 +223,6 @@ var BackgroundCache = class BackgroundCache {
         }
     }
 };
-Signals.addSignalMethods(BackgroundCache.prototype);
 
 function getBackgroundCache() {
     if (!_backgroundCache)
@@ -682,8 +683,9 @@ class Animation extends GnomeDesktop.BGSlideShow {
     }
 });
 
-var BackgroundManager = class BackgroundManager {
+var BackgroundManager = class BackgroundManager extends Signals.EventEmitter {
     constructor(params) {
+        super();
         params = Params.parse(params, {
             container: null,
             layoutManager: Main.layoutManager,
@@ -838,4 +840,3 @@ var BackgroundManager = class BackgroundManager {
         return backgroundActor;
     }
 };
-Signals.addSignalMethods(BackgroundManager.prototype);

js/ui/components/networkAgent.js

@@ -2,7 +2,7 @@
 /* exported Component */
 
 const { Clutter, Gio, GLib, GObject, NM, Pango, Shell, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Dialog = imports.ui.dialog;
 const Main = imports.ui.main;
@@ -411,8 +411,10 @@ class NetworkSecretDialog extends ModalDialog.ModalDialog {
     }
 });
 
-var VPNRequestHandler = class {
+var VPNRequestHandler = class extends Signals.EventEmitter {
     constructor(agent, requestId, authHelper, serviceType, connection, hints, flags) {
+        super();
+
         this._agent = agent;
         this._requestId = requestId;
         this._connection = connection;
@@ -668,7 +670,6 @@ var VPNRequestHandler = class {
         }
     }
 };
-Signals.addSignalMethods(VPNRequestHandler.prototype);
 
 var NetworkAgent = class {
     constructor() {

js/ui/dnd.js

@@ -2,7 +2,7 @@
 /* exported addDragMonitor, removeDragMonitor, makeDraggable */
 
 const { Clutter, GLib, Meta, Shell, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Main = imports.ui.main;
 const Params = imports.misc.params;
@@ -78,8 +78,10 @@ function removeDragMonitor(monitor) {
     }
 }
 
-var _Draggable = class _Draggable {
+var _Draggable = class _Draggable extends Signals.EventEmitter {
     constructor(actor, params) {
+        super();
+
         params = Params.parse(params, {
             manualMode: false,
             timeoutThreshold: 0,
@@ -801,7 +803,6 @@ var _Draggable = class _Draggable {
         currentDraggable = null;
     }
 };
-Signals.addSignalMethods(_Draggable.prototype);
 
 /**
  * makeDraggable:

js/ui/environment.js

@@ -45,7 +45,6 @@ try {
 
 const { Clutter, Gio, GLib, GObject, Meta, Polkit, Shell, St } = imports.gi;
 const Gettext = imports.gettext;
-const Signals = imports.signals;
 const System = imports.system;
 const SignalTracker = imports.misc.signalTracker;
 
@@ -358,12 +357,6 @@ function init() {
         SignalTracker.disconnectObject(this, ...args);
     };
 
-    const _addSignalMethods = Signals.addSignalMethods;
-    Signals.addSignalMethods = function (prototype) {
-        _addSignalMethods(prototype);
-        SignalTracker.addObjectSignalMethods(prototype);
-    };
-
     SignalTracker.registerDestroyableType(Clutter.Actor);
 
     // Miscellaneous monkeypatching

js/ui/extensionSystem.js

@@ -1,8 +1,8 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
-/* exported init connect disconnect */
+/* exported init connect disconnect ExtensionManager */
 
 const { GLib, Gio, GObject, Shell, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const ExtensionDownloader = imports.ui.extensionDownloader;
 const ExtensionUtils = imports.misc.extensionUtils;
@@ -19,8 +19,10 @@ const EXTENSION_DISABLE_VERSION_CHECK_KEY = 'disable-extension-version-validatio
 
 const UPDATE_CHECK_TIMEOUT = 24 * 60 * 60; // 1 day in seconds
 
-var ExtensionManager = class {
+var ExtensionManager = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._initialized = false;
         this._updateNotified = false;
 
@@ -655,7 +657,6 @@ var ExtensionManager = class {
         this._enableAllExtensions();
     }
 };
-Signals.addSignalMethods(ExtensionManager.prototype);
 
 const ExtensionUpdateSource = GObject.registerClass(
 class ExtensionUpdateSource extends MessageTray.Source {

js/ui/focusCaretTracker.js

@@ -20,15 +20,18 @@
  * Contributor:
  *   Magdalen Berns <m.berns@sms.ed.ac.uk>
  */
+/* exported FocusCaretTracker */
 
 const Atspi = imports.gi.Atspi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const CARETMOVED        = 'object:text-caret-moved';
 const STATECHANGED      = 'object:state-changed';
 
-var FocusCaretTracker = class FocusCaretTracker {
+var FocusCaretTracker = class FocusCaretTracker extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._atspiListener = Atspi.EventListener.new(this._onChanged.bind(this));
 
         this._atspiInited = false;
@@ -86,4 +89,3 @@ var FocusCaretTracker = class FocusCaretTracker {
         this._caretListenerRegistered = false;
     }
 };
-Signals.addSignalMethods(FocusCaretTracker.prototype);

js/ui/keyboard.js

@@ -2,7 +2,7 @@
 /* exported KeyboardManager */
 
 const { Clutter, Gio, GLib, GObject, Graphene, Meta, Shell, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const EdgeDragAction = imports.ui.edgeDragAction;
 const InputSourceManager = imports.ui.status.keyboard;
@@ -574,8 +574,10 @@ var KeyboardModel = class {
     }
 };
 
-var FocusTracker = class {
+var FocusTracker = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._rect = null;
 
         global.display.connectObject(
@@ -670,7 +672,6 @@ var FocusTracker = class {
         return rect;
     }
 };
-Signals.addSignalMethods(FocusTracker.prototype);
 
 var EmojiPager = GObject.registerClass({
     Properties: {
@@ -2055,8 +2056,10 @@ var Keyboard = GObject.registerClass({
     }
 });
 
-var KeyboardController = class {
+var KeyboardController = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         let seat = Clutter.get_default_backend().get_default_seat();
         this._virtualDevice = seat.create_virtual_device(Clutter.InputDeviceType.KEYBOARD_DEVICE);
 
@@ -2147,4 +2150,3 @@ var KeyboardController = class {
                                           keyval, Clutter.KeyState.RELEASED);
     }
 };
-Signals.addSignalMethods(KeyboardController.prototype);

js/ui/layout.js

@@ -2,7 +2,7 @@
 /* exported MonitorConstraint, LayoutManager */
 
 const { Clutter, Gio, GLib, GObject, Meta, Shell, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Background = imports.ui.background;
 const BackgroundMenu = imports.ui.backgroundMenu;
@@ -1268,8 +1268,10 @@ class HotCorner extends Clutter.Actor {
     }
 });
 
-var PressureBarrier = class PressureBarrier {
+var PressureBarrier = class PressureBarrier extends Signals.EventEmitter {
     constructor(threshold, timeout, actionMode) {
+        super();
+
         this._threshold = threshold;
         this._timeout = timeout;
         this._actionMode = actionMode;
@@ -1409,7 +1411,6 @@ var PressureBarrier = class PressureBarrier {
             this._trigger();
     }
 };
-Signals.addSignalMethods(PressureBarrier.prototype);
 
 var ScreenTransition = GObject.registerClass(
 class ScreenTransition extends Clutter.Actor {

js/ui/lookingGlass.js

@@ -4,7 +4,7 @@
 const {
     Clutter, Cogl, Gio, GLib, GObject, Graphene, Meta, Pango, Shell, St,
 } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 const System = imports.system;
 
 const History = imports.misc.history;
@@ -56,8 +56,10 @@ function _getAutoCompleteGlobalKeywords() {
     return keywords.concat(windowProperties).concat(headerProperties);
 }
 
-var AutoComplete = class AutoComplete {
+var AutoComplete = class AutoComplete extends Signals.EventEmitter {
     constructor(entry) {
+        super();
+
         this._entry = entry;
         this._entry.connect('key-press-event', this._entryKeyPressEvent.bind(this));
         this._lastTabTime = global.get_current_time();
@@ -121,7 +123,6 @@ var AutoComplete = class AutoComplete {
         this._entry.clutter_text.insert_text(additionalCompletionText, cursorPos);
     }
 };
-Signals.addSignalMethods(AutoComplete.prototype);
 
 
 var Notebook = GObject.registerClass({

js/ui/magnifier.js

@@ -1,9 +1,10 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/* exported Magnifier */
 
 const {
     Atspi, Clutter, GDesktopEnums, Gio, GLib, GObject, Meta, Shell, St,
 } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Background = imports.ui.background;
 const FocusCaretTracker = imports.ui.focusCaretTracker;
@@ -88,8 +89,10 @@ var MouseSpriteContent = GObject.registerClass({
     }
 });
 
-var Magnifier = class Magnifier {
+var Magnifier = class Magnifier extends Signals.EventEmitter {
     constructor() {
+        super();
+
         // Magnifier is a manager of ZoomRegions.
         this._zoomRegions = [];
 
@@ -724,7 +727,6 @@ var Magnifier = class Magnifier {
         }
     }
 };
-Signals.addSignalMethods(Magnifier.prototype);
 
 var ZoomRegion = class ZoomRegion {
     constructor(magnifier, mouseSourceActor) {

js/ui/mpris.js

@@ -1,6 +1,6 @@
 /* exported MediaSection */
 const { Gio, GObject, Shell, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Main = imports.ui.main;
 const MessageList = imports.ui.messageList;
@@ -86,14 +86,16 @@ class MediaMessage extends MessageList.Message {
     }
 });
 
-var MprisPlayer = class MprisPlayer {
+var MprisPlayer = class MprisPlayer extends Signals.EventEmitter {
     constructor(busName) {
+        super();
+
         this._mprisProxy = new MprisProxy(Gio.DBus.session, busName,
-                                          '/org/mpris/MediaPlayer2',
+            '/org/mpris/MediaPlayer2',
-                                          this._onMprisProxyReady.bind(this));
+            this._onMprisProxyReady.bind(this));
         this._playerProxy = new MprisPlayerProxy(Gio.DBus.session, busName,
-                                                 '/org/mpris/MediaPlayer2',
+            '/org/mpris/MediaPlayer2',
-                                                 this._onPlayerProxyReady.bind(this));
+            this._onPlayerProxyReady.bind(this));
 
         this._visible = false;
         this._trackArtists = [];
@@ -233,7 +235,6 @@ var MprisPlayer = class MprisPlayer {
         }
     }
 };
-Signals.addSignalMethods(MprisPlayer.prototype);
 
 var MediaSection = GObject.registerClass(
 class MediaSection extends MessageList.MessageListSection {

js/ui/overview.js

@@ -2,7 +2,7 @@
 /* exported Overview, ANIMATION_TIME */
 
 const { Clutter, Gio, GLib, GObject, Meta, Shell, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 // Time for initial animation going into Overview mode;
 // this is defined here to make it available in imports.
@@ -103,8 +103,10 @@ class OverviewActor extends St.BoxLayout {
     }
 });
 
-var Overview = class {
+var Overview = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._initCalled = false;
         this._visible = false;
 
@@ -649,4 +651,3 @@ var Overview = class {
         return this._overview.searchEntry;
     }
 };
-Signals.addSignalMethods(Overview.prototype);

js/ui/padOsd.js

@@ -5,7 +5,7 @@ const {
     Atk, Clutter, GDesktopEnums, Gio,
     GLib, GObject, Gtk, Meta, Pango, Rsvg, St,
 } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Main = imports.ui.main;
 const PopupMenu = imports.ui.popupMenu;
@@ -957,8 +957,10 @@ var PadOsd = GObject.registerClass({
 
 const PadOsdIface = loadInterfaceXML('org.gnome.Shell.Wacom.PadOsd');
 
-var PadOsdService = class {
+var PadOsdService = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._dbusImpl = Gio.DBusExportedObject.wrapJSObject(PadOsdIface, this);
         this._dbusImpl.export(Gio.DBus.session, '/org/gnome/Shell/Wacom');
         Gio.DBus.session.own_name('org.gnome.Shell.Wacom.PadOsd', Gio.BusNameOwnerFlags.REPLACE, null, null);
@@ -987,4 +989,3 @@ var PadOsdService = class {
         invocation.return_value(null);
     }
 };
-Signals.addSignalMethods(PadOsdService.prototype);

js/ui/popupMenu.js

@@ -4,7 +4,7 @@
             PopupMenuSection, PopupSubMenuMenuItem, PopupMenuManager */
 
 const { Atk, Clutter, Gio, GObject, Graphene, Shell, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const BoxPointer = imports.ui.boxpointer;
 const Main = imports.ui.main;
@@ -480,8 +480,10 @@ class PopupImageMenuItem extends PopupBaseMenuItem {
     }
 });
 
-var PopupMenuBase = class {
+var PopupMenuBase = class extends Signals.EventEmitter {
     constructor(sourceActor, styleClass) {
+        super();
+
         if (this.constructor === PopupMenuBase)
             throw new TypeError(`Cannot instantiate abstract class ${this.constructor.name}`);
 
@@ -805,7 +807,6 @@ var PopupMenuBase = class {
         Main.sessionMode.disconnectObject(this);
     }
 };
-Signals.addSignalMethods(PopupMenuBase.prototype);
 
 var PopupMenu = class extends PopupMenuBase {
     constructor(sourceActor, arrowAlignment, arrowSide) {
@@ -951,8 +952,10 @@ var PopupMenu = class extends PopupMenuBase {
     }
 };
 
-var PopupDummyMenu = class {
+var PopupDummyMenu = class extends Signals.EventEmitter {
     constructor(sourceActor) {
+        super();
+
         this.sourceActor = sourceActor;
         this.actor = sourceActor;
         this.actor._delegate = this;
@@ -986,7 +989,6 @@ var PopupDummyMenu = class {
         this.emit('destroy');
     }
 };
-Signals.addSignalMethods(PopupDummyMenu.prototype);
 
 var PopupSubMenu = class extends PopupMenuBase {
     constructor(sourceActor, sourceArrow) {

js/ui/screenShield.js

@@ -1,10 +1,11 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/* exported ScreenShield */
 
 const {
     AccountsService, Clutter, Gio,
     GLib, Graphene, Meta, Shell, St,
 } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const GnomeSession = imports.misc.gnomeSession;
 const OVirt = imports.gdm.oVirt;
@@ -44,8 +45,10 @@ var CURTAIN_SLIDE_TIME = 300;
  * This will ensure that the screen blanks at the right time when it fades out.
  * https://bugzilla.gnome.org/show_bug.cgi?id=668703 explains the dependency.
  */
-var ScreenShield = class {
+var ScreenShield = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this.actor = Main.layoutManager.screenShieldGroup;
 
         this._lockScreenState = MessageTray.State.HIDDEN;
@@ -676,4 +679,3 @@ var ScreenShield = class {
         });
     }
 };
-Signals.addSignalMethods(ScreenShield.prototype);

js/ui/sessionMode.js

@@ -2,7 +2,7 @@
 /* exported SessionMode, listModes */
 
 const GLib = imports.gi.GLib;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const FileUtils = imports.misc.fileUtils;
 const Params = imports.misc.params;
@@ -145,8 +145,10 @@ function listModes() {
     loop.run();
 }
 
-var SessionMode = class {
+var SessionMode = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         _loadModes();
         let isPrimary = _modes[global.session_mode] &&
                          _modes[global.session_mode].isPrimary;
@@ -199,4 +201,3 @@ var SessionMode = class {
         this.emit('updated');
     }
 };
-Signals.addSignalMethods(SessionMode.prototype);

js/ui/status/keyboard.js

@@ -3,7 +3,7 @@
 
 const { Clutter, Gio, GLib, GObject, IBus, Meta, Shell, St } = imports.gi;
 const Gettext = imports.gettext;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const IBusManager = imports.misc.ibusManager;
 const KeyboardManager = imports.misc.keyboardManager;
@@ -32,8 +32,10 @@ class LayoutMenuItem extends PopupMenu.PopupBaseMenuItem {
     }
 });
 
-var InputSource = class {
+var InputSource = class extends Signals.EventEmitter {
     constructor(type, id, displayName, shortName, index) {
+        super();
+
         this.type = type;
         this.id = id;
         this.displayName = displayName;
@@ -69,7 +71,6 @@ var InputSource = class {
             return engineDesc.layout;
     }
 };
-Signals.addSignalMethods(InputSource.prototype);
 
 var InputSourcePopup = GObject.registerClass(
 class InputSourcePopup extends SwitcherPopup.SwitcherPopup {
@@ -135,8 +136,10 @@ class InputSourceSwitcher extends SwitcherPopup.SwitcherList {
     }
 });
 
-var InputSourceSettings = class {
+var InputSourceSettings = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         if (this.constructor === InputSourceSettings)
             throw new TypeError(`Cannot instantiate abstract class ${this.constructor.name}`);
     }
@@ -173,7 +176,6 @@ var InputSourceSettings = class {
         return false;
     }
 };
-Signals.addSignalMethods(InputSourceSettings.prototype);
 
 var InputSourceSystemSettings = class extends InputSourceSettings {
     constructor() {
@@ -300,8 +302,10 @@ var InputSourceSessionSettings = class extends InputSourceSettings {
     }
 };
 
-var InputSourceManager = class {
+var InputSourceManager = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         // All valid input sources currently in the gsettings
         // KEY_INPUT_SOURCES list indexed by their index there
         this._inputSources = {};
@@ -771,7 +775,6 @@ var InputSourceManager = class {
         return this._keyboardManager;
     }
 };
-Signals.addSignalMethods(InputSourceManager.prototype);
 
 let _inputSourceManager = null;
 

js/ui/status/network.js

@@ -1,7 +1,7 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 /* exported NMApplet */
 const { Clutter, Gio, GLib, GObject, Meta, NM, Polkit, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Animation = imports.ui.animation;
 const Main = imports.ui.main;
@@ -107,8 +107,10 @@ function launchSettingsPanel(panel, ...args) {
     }
 }
 
-var NMConnectionItem = class {
+var NMConnectionItem = class extends Signals.EventEmitter {
     constructor(section, connection) {
+        super();
+
         this._section = section;
         this._connection = connection;
         this._activeConnection = null;
@@ -193,10 +195,11 @@ var NMConnectionItem = class {
         this._sync();
     }
 };
-Signals.addSignalMethods(NMConnectionItem.prototype);
 
-var NMConnectionSection = class NMConnectionSection {
+var NMConnectionSection = class NMConnectionSection extends Signals.EventEmitter {
     constructor(client) {
+        super();
+
         if (this.constructor === NMConnectionSection)
             throw new TypeError(`Cannot instantiate abstract type ${this.constructor.name}`);
 
@@ -320,7 +323,6 @@ var NMConnectionSection = class NMConnectionSection {
         this._sync();
     }
 };
-Signals.addSignalMethods(NMConnectionSection.prototype);
 
 var NMConnectionDevice = class NMConnectionDevice extends NMConnectionSection {
     constructor(client, device) {
@@ -1242,8 +1244,10 @@ class NMWirelessDialog extends ModalDialog.ModalDialog {
     }
 });
 
-var NMDeviceWireless = class {
+var NMDeviceWireless = class extends Signals.EventEmitter {
     constructor(client, device) {
+        super();
+
         this._client = client;
         this._device = device;
 
@@ -1433,7 +1437,6 @@ var NMDeviceWireless = class {
             return 'network-wireless-no-route-symbolic';
     }
 };
-Signals.addSignalMethods(NMDeviceWireless.prototype);
 
 var NMWireguardItem = class extends NMConnectionItem {
     _buildUI() {
@@ -1657,7 +1660,6 @@ var NMVpnSection = class extends NMConnectionSection {
         return '';
     }
 };
-Signals.addSignalMethods(NMVpnSection.prototype);
 
 var DeviceCategory = class extends PopupMenu.PopupMenuSection {
     constructor(category) {

js/ui/status/rfkill.js

@@ -2,7 +2,7 @@
 /* exported Indicator */
 
 const { Gio, GObject } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Main = imports.ui.main;
 const PanelMenu = imports.ui.panelMenu;
@@ -16,18 +16,20 @@ const OBJECT_PATH = '/org/gnome/SettingsDaemon/Rfkill';
 const RfkillManagerInterface = loadInterfaceXML('org.gnome.SettingsDaemon.Rfkill');
 const RfkillManagerProxy = Gio.DBusProxy.makeProxyWrapper(RfkillManagerInterface);
 
-var RfkillManager = class {
+var RfkillManager = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._proxy = new RfkillManagerProxy(Gio.DBus.session, BUS_NAME, OBJECT_PATH,
-                                             (proxy, error) => {
+            (proxy, error) => {
-                                                 if (error) {
+                if (error) {
-                                                     log(error.message);
+                    log(error.message);
-                                                     return;
+                    return;
-                                                 }
+                }
-                                                 this._proxy.connect('g-properties-changed',
+                this._proxy.connect('g-properties-changed',
-                                                                     this._changed.bind(this));
+                    this._changed.bind(this));
-                                                 this._changed();
+                this._changed();
-                                             });
+            });
     }
 
     get airplaneMode() {
@@ -50,7 +52,6 @@ var RfkillManager = class {
         this.emit('airplane-mode-changed');
     }
 };
-Signals.addSignalMethods(RfkillManager.prototype);
 
 var _manager;
 function getRfkillManager() {

js/ui/status/thunderbolt.js

@@ -4,7 +4,7 @@
 // the following is a modified version of bolt/contrib/js/client.js
 
 const { Gio, GLib, GObject, Polkit, Shell } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Main = imports.ui.main;
 const MessageTray = imports.ui.messageTray;
@@ -49,8 +49,10 @@ const BOLT_DBUS_CLIENT_IFACE = 'org.freedesktop.bolt1.Manager';
 const BOLT_DBUS_NAME = 'org.freedesktop.bolt';
 const BOLT_DBUS_PATH = '/org/freedesktop/bolt';
 
-var Client = class {
+var Client = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         this._proxy = null;
         this.probing = false;
         this._getProxy();
@@ -127,11 +129,12 @@ var Client = class {
         return this._proxy.AuthMode;
     }
 };
-Signals.addSignalMethods(Client.prototype);
 
 /* helper class to automatically authorize new devices */
-var AuthRobot = class {
+var AuthRobot = class extends Signals.EventEmitter {
     constructor(client) {
+        super();
+
         this._client = client;
 
         this._devicesToEnroll = [];
@@ -217,7 +220,6 @@ var AuthRobot = class {
         return GLib.SOURCE_REMOVE;
     }
 };
-Signals.addSignalMethods(AuthRobot.prototype);
 
 /* eof client.js  */
 

js/ui/status/volume.js

@@ -2,7 +2,7 @@
 /* exported Indicator */
 
 const { Clutter, Gio, GLib, GObject, Gvc, St } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Main = imports.ui.main;
 const PanelMenu = imports.ui.panelMenu;
@@ -29,8 +29,10 @@ function getMixerControl() {
     return _mixerControl;
 }
 
-var StreamSlider = class {
+var StreamSlider = class extends Signals.EventEmitter {
     constructor(control) {
+        super();
+
         this._control = control;
 
         this.item = new PopupMenu.PopupBaseMenuItem({ activate: false });
@@ -213,7 +215,6 @@ var StreamSlider = class {
         return maxVolume / this._control.get_vol_max_norm();
     }
 };
-Signals.addSignalMethods(StreamSlider.prototype);
 
 var OutputStreamSlider = class extends StreamSlider {
     constructor(control) {

js/ui/xdndHandler.js

@@ -1,13 +1,16 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+/* exported XdndHandler */
 
 const { Clutter } = imports.gi;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const DND = imports.ui.dnd;
 const Main = imports.ui.main;
 
-var XdndHandler = class {
+var XdndHandler = class extends Signals.EventEmitter {
     constructor() {
+        super();
+
         // Used to display a clone of the cursor window when the
         // window group is hidden (like it happens in the overview)
         this._cursorWindowClone = null;
@@ -111,4 +114,3 @@ var XdndHandler = class {
         }
     }
 };
-Signals.addSignalMethods(XdndHandler.prototype);

tests/unit/signalTracker.js

@@ -5,7 +5,7 @@
 const { GObject } = imports.gi;
 
 const JsUnit = imports.jsUnit;
-const Signals = imports.signals;
+const Signals = imports.misc.signals;
 
 const Environment = imports.ui.environment;
 const { TransientSignalHolder, registerDestroyableType } = imports.misc.signalTracker;
@@ -17,14 +17,11 @@ const Destroyable = GObject.registerClass({
 }, class Destroyable extends GObject.Object {});
 registerDestroyableType(Destroyable);
 
-class PlainEmitter {}
-Signals.addSignalMethods(PlainEmitter.prototype);
-
 const GObjectEmitter = GObject.registerClass({
     Signals: { 'signal': {} },
 }, class GObjectEmitter extends Destroyable {});
 
-const emitter1 = new PlainEmitter();
+const emitter1 = new Signals.EventEmitter();
 const emitter2 = new GObjectEmitter();
 
 const tracked1 = new Destroyable();