[Chromoting] Change Application.Delegate to proper subclass of Application.

remoting/webapp/base/js/application.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * Interface abstracting the Application functionality.
  */
 
 'use strict';
 
 /** @suppress {duplicate} */
 var remoting = remoting || {};
 
 /**
  * @param {Array<string>} appCapabilities Array of application capabilities.
  * @constructor
+ * @implements {remoting.ApplicationInterface}
  */
 remoting.Application = function(appCapabilities) {
-  /** @private {remoting.Application.Delegate} */
-  this.delegate_ = null;
+  // Create global factories.
+  remoting.ClientPlugin.factory = new remoting.DefaultClientPluginFactory();
+  remoting.SessionConnector.factory =
+      new remoting.DefaultSessionConnectorFactory();
 
   /** @private {Array<string>} */
   this.appCapabilities_ = [
     remoting.ClientSession.Capability.SEND_INITIAL_RESOLUTION,
     remoting.ClientSession.Capability.RATE_LIMIT_RESIZE_REQUESTS,
     remoting.ClientSession.Capability.VIDEO_RECORDER
   ];
   // Append the app-specific capabilities.
   this.appCapabilities_.push.apply(this.appCapabilities_, appCapabilities);
 
-  /** @private {remoting.SessionConnector} */
-  this.sessionConnector_ = null;
+  /** @protected {remoting.SessionConnector} */
+  this.sessionConnector_ = remoting.SessionConnector.factory.createConnector(
+      document.getElementById('client-container'),
+      this.onConnected_.bind(this),
+      this.onError_.bind(this),
+      this.onConnectionFailed_.bind(this),
+      this.appCapabilities_);
 
   /** @private {base.Disposable} */
   this.sessionConnectedHooks_ = null;
 };
 
 /**
- * @param {remoting.Application.Delegate} appDelegate The delegate that
- *    contains the app-specific functionality.
+ * @return {remoting.SessionConnector} The session connector.
  */
-remoting.Application.prototype.setDelegate = function(appDelegate) {
-  this.delegate_ = appDelegate;
+remoting.Application.prototype.getSessionConnector = function() {
+  return this.sessionConnector_;
 };
 
 /**
- * @return {string} Application product name to be used in UI.
- */
-remoting.Application.prototype.getApplicationName = function() {
-  return this.delegate_.getApplicationName();
-};
-
-/**
  * @param {remoting.ClientSession.Capability} capability
  * @return {boolean}
  */
 remoting.Application.prototype.hasCapability = function(capability) {
   var capabilities = this.appCapabilities_;
   return capabilities.indexOf(capability) != -1;
 };
 
+/* Disconnect the remoting client. */
+remoting.Application.prototype.disconnect = function() {
+  if (remoting.clientSession) {
+    remoting.clientSession.disconnect(remoting.Error.none());
+    console.log('Disconnected.');
+  }
+};
+
+/* Public method to exit the application. */
+remoting.Application.prototype.quit = function() {
+  this.exitApplication_();
+};
+
+/**
+ * Close the main window when quitting the application. This should be called
+ * by exitApplication() in the subclass.
+ * @protected
+ */
+remoting.Application.prototype.closeMainWindow_ = function() {
+  chrome.app.window.current().close();
+};
+
 /**
  * Initialize the application and register all event handlers. After this
  * is called, the app is running and waiting for user events.
- *
- * @return {void} Nothing.
  */
 remoting.Application.prototype.start = function() {
-  // Create global objects.
-  remoting.ClientPlugin.factory = new remoting.DefaultClientPluginFactory();
-  remoting.SessionConnector.factory =
-      new remoting.DefaultSessionConnectorFactory();
-
   // TODO(garykac): This should be owned properly rather than living in the
   // global 'remoting' namespace.
   remoting.settings = new remoting.Settings();
 
   remoting.initGlobalObjects();
   remoting.initIdentity();
 
-  this.delegate_.init();
+  this.initApplication_();
 
   var that = this;
-  remoting.identity.getToken().then(
-      this.delegate_.start.bind(this.delegate_, this.getSessionConnector())
-  ).catch(remoting.Error.handler(
+  remoting.identity.getToken().
+    then(this.startApplication_.bind(this)).
+    catch(remoting.Error.handler(
       function(/** !remoting.Error */ error) {
         if (error.hasTag(remoting.Error.Tag.CANCELLED)) {
-          that.exit();
+          that.exitApplication_();
         } else {
-          that.delegate_.signInFailed(error);
+          that.signInFailed_(error);
         }
       }
     )
   );
 };
 
 /**
- * Quit the application.
- */
-remoting.Application.prototype.exit = function() {
-  this.delegate_.handleExit();
-  chrome.app.window.current().close();
-};
-
-/** Disconnect the remoting client. */
-remoting.Application.prototype.disconnect = function() {
-  if (remoting.clientSession) {
-    remoting.clientSession.disconnect(remoting.Error.none());
-    console.log('Disconnected.');
-  }
-};
-
-/**
  * Called when a new session has been connected.
  *
  * @param {remoting.ConnectionInfo} connectionInfo
  * @return {void} Nothing.
+ * @protected
  */
-remoting.Application.prototype.onConnected = function(connectionInfo) {
+remoting.Application.prototype.initSession_ = function(connectionInfo) {
   this.sessionConnectedHooks_ = new base.Disposables(
     new base.EventHook(connectionInfo.session(), 'stateChanged',
                        this.onSessionFinished_.bind(this)),
     new base.RepeatingTimer(this.updateStatistics_.bind(this), 1000)
   );
   remoting.clipboard.startSession();
-
-  this.delegate_.handleConnected(connectionInfo);
 };
 
 /**
- * Called when the current session has been disconnected.
- *
- * @return {void} Nothing.
- */
-remoting.Application.prototype.onDisconnected = function() {
-  this.delegate_.handleDisconnected();
-};
-
-/**
- * Called when the current session's connection has failed.
- *
- * @param {!remoting.Error} error
- * @return {void} Nothing.
- */
-remoting.Application.prototype.onConnectionFailed = function(error) {
-  this.delegate_.handleConnectionFailed(this.sessionConnector_, error);
-};
-
-/**
- * Called when an error needs to be displayed to the user.
- *
- * @param {!remoting.Error} errorTag The error to be localized and displayed.
- * @return {void} Nothing.
- */
-remoting.Application.prototype.onError = function(errorTag) {
-  this.delegate_.handleError(errorTag);
-};
-
-/**
- * @return {remoting.SessionConnector} A session connector, creating a new one
- *     if necessary.
- */
-remoting.Application.prototype.getSessionConnector = function() {
-  // TODO(garykac): Check if this can be initialized in the ctor.
-  if (!this.sessionConnector_) {
-    this.sessionConnector_ = remoting.SessionConnector.factory.createConnector(
-        document.getElementById('client-container'),
-        this.onConnected.bind(this),
-        this.onError.bind(this),
-        this.onConnectionFailed.bind(this),
-        this.appCapabilities_);
-  }
-  return this.sessionConnector_;
-};
-
-/**
  * Callback function called when the state of the client plugin changes. The
  * current and previous states are available via the |state| member variable.
  *
  * @param {remoting.ClientSession.StateEvent=} state
  * @private
  */
 remoting.Application.prototype.onSessionFinished_ = function(state) {
   switch (state.current) {
     case remoting.ClientSession.State.CLOSED:
       console.log('Connection closed by host');
-      this.onDisconnected();
+      this.onDisconnected_();
       break;
     case remoting.ClientSession.State.FAILED:
       var error = remoting.clientSession.getError();
       console.error('Client plugin reported connection failed: ' +
                     error.toString());
       if (error === null) {
         error = remoting.Error.unexpected();
       }
-      this.onError(error);
+      this.onError_(error);
       break;
 
     default:
       console.error('Unexpected client plugin state: ' + state.current);
       // This should only happen if the web-app and client plugin get out of
       // sync, so MISSING_PLUGIN is a suitable error.
-      this.onError(new remoting.Error(remoting.Error.Tag.MISSING_PLUGIN));
+      this.onError_(new remoting.Error(remoting.Error.Tag.MISSING_PLUGIN));
       break;
   }
 
   base.dispose(this.sessionConnectedHooks_);
   this.sessionConnectedHooks_= null;
   this.sessionConnector_.closeSession();
 };
 
 /** @private */
 remoting.Application.prototype.updateStatistics_ = function() {
   var perfstats = remoting.clientSession.getPerfStats();
   remoting.stats.update(perfstats);
   remoting.clientSession.logStatistics(perfstats);
 };
 
 
+/*
+ * remoting.ApplicationInterface
+ * These functions must be overridden in the subclass.
+ */
+
+/** @return {string} */
+remoting.Application.prototype.getApplicationName = function() {
+  base.debug.assert(false, "Subclass must override");
+};
+
+/**
+ * @param {!remoting.Error} error
+ * @protected
+ */
+remoting.Application.prototype.signInFailed_ = function(error) {
+  base.debug.assert(false, "Subclass must override");
+};
+
+/** @protected */
+remoting.Application.prototype.initApplication_ = function() {
+  base.debug.assert(false, "Subclass must override");
+};
+
+/**
+ * @param {string} token
+ * @protected
+ */
+remoting.Application.prototype.startApplication_ = function(token) {
+  base.debug.assert(false, "Subclass must override");
+};
+
+/** @protected */
+remoting.Application.prototype.exitApplication_ = function() {
+  base.debug.assert(false, "Subclass must override");
+};
+
+/**
+ * @param {remoting.ConnectionInfo} connectionInfo
+ * @protected
+ */
+remoting.Application.prototype.onConnected_ = function(connectionInfo) {
+  base.debug.assert(false, "Subclass must override");
+};
+
+/** @protected */
+remoting.Application.prototype.onDisconnected_ = function() {
+  base.debug.assert(false, "Subclass must override");
+};
+
+/**
+ * @param {!remoting.Error} error
+ * @protected
+ */
+remoting.Application.prototype.onConnectionFailed_ = function(error) {
+  base.debug.assert(false, "Subclass must override");
+};
+
+/**
+ * @param {!remoting.Error} error The error to be localized and displayed.
+ * @protected
+ */
+remoting.Application.prototype.onError_ = function(error) {
+  base.debug.assert(false, "Subclass must override");
+};
+
+
 /**
+ * The interface specifies the methods that a subclass of remoting.Application
+ * is required implement to override the default behavior.
+ *
  * @interface
  */
-remoting.Application.Delegate = function() {};
+remoting.ApplicationInterface = function() {};
+
+/**
+ * @return {string} Application product name to be used in UI.
+ */
+remoting.ApplicationInterface.prototype.getApplicationName = function() {};
+
+/**
+ * Report an authentication error to the user. This is called in lieu of
+ * startApplication() if the user cannot be authenticated or if they decline
+ * the app permissions.
+ *
+ * @param {!remoting.Error} error The failure reason.
+ */
+remoting.ApplicationInterface.prototype.signInFailed_ = function(error) {};
 
 /**
  * Initialize the application. This is called before an OAuth token is requested
  * and should be used for tasks such as initializing the DOM, registering event
- * handlers, etc.
+ * handlers, etc. After this is called, the app is running and waiting for
+ * user events.
  */
-remoting.Application.Delegate.prototype.init = function() {};
+remoting.ApplicationInterface.prototype.initApplication_ = function() {};
 
 /**
- * Start the application. Once start() is called, the delegate can assume that
+ * Start the application. Once startApplication() is called, we can assume that
  * the user has consented to all permissions specified in the manifest.
  *
- * @param {remoting.SessionConnector} connector
- * @param {string} token An OAuth access token. The delegate should not cache
+ * @param {string} token An OAuth access token. The app should not cache
  *     this token, but can assume that it will remain valid during application
  *     start-up.
  */
-remoting.Application.Delegate.prototype.start = function(connector, token) {};
+remoting.ApplicationInterface.prototype.startApplication_ = function(token) {};
 
 /**
- * Report an authentication error to the user. This is called in lieu of start()
- * if the user cannot be authenticated.
- *
- * @param {!remoting.Error} error The failure reason.
+ * Close down the application before exiting.
  */
-remoting.Application.Delegate.prototype.signInFailed = function(error) {};
-
-/**
- * @return {string} Application product name to be used in UI.
- */
-remoting.Application.Delegate.prototype.getApplicationName = function() {};
+remoting.ApplicationInterface.prototype.exitApplication_ = function() {};
 
 /**
  * Called when a new session has been connected.
  *
  * @param {remoting.ConnectionInfo} connectionInfo
- * @return {void} Nothing.
  */
-remoting.Application.Delegate.prototype.handleConnected = function(
-    connectionInfo) {};
+remoting.ApplicationInterface.prototype.onConnected_ =
+    function(connectionInfo) {};
 
 /**
  * Called when the current session has been disconnected.
- *
- * @return {void} Nothing.
  */
-remoting.Application.Delegate.prototype.handleDisconnected = function() {};
+remoting.ApplicationInterface.prototype.onDisconnected_ = function() {};
 
 /**
  * Called when the current session's connection has failed.
  *
- * @param {remoting.SessionConnector} connector
  * @param {!remoting.Error} error
- * @return {void} Nothing.
  */
-remoting.Application.Delegate.prototype.handleConnectionFailed =
-    function(connector, error) {};
+remoting.ApplicationInterface.prototype.onConnectionFailed_ =
+    function(error) {};
 
 /**
  * Called when an error needs to be displayed to the user.
  *
  * @param {!remoting.Error} errorTag The error to be localized and displayed.
- * @return {void} Nothing.
  */
-remoting.Application.Delegate.prototype.handleError = function(errorTag) {};
-
-/**
- * Perform any application-specific cleanup before exiting. This is called in
- * lieu of start() if the user declines the app permissions, and will usually
- * be called immediately prior to exiting, although delegates should not rely
- * on this.
- */
-remoting.Application.Delegate.prototype.handleExit = function() {};
+remoting.ApplicationInterface.prototype.onError_ = function(errorTag) {};
 
 
 /** @type {remoting.Application} */
 remoting.app = null;