remoting/webapp/base/js/protocol_extension_manager.js

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 /** @suppress {duplicate} */
   6 var remoting = remoting || {};
   7
   8 (function() {
   9
  10 'use strict';
  11
  12 /**
  13  * @param {function(string, string)} sendExtensionMessage Callback used to
  14  *     send an extension message to the plugin.
  15  * @constructor
  16  * @implements {base.Disposable}
  17  */
  18 remoting.ProtocolExtensionManager = function(sendExtensionMessage) {
  19   /** @private */
  20   this.sendExtensionMessage_ = sendExtensionMessage;
  21   /** @private {Object<remoting.ProtocolExtension>} */
  22   this.protocolExtensions_ = {};
  23
  24   /**
  25    * True once a session has been created and we've started the extensions.
  26    * This is used to immediately start any extensions that are registered
  27    * after the CONNECTED state change.
  28    * @private
  29    */
  30   this.protocolExtensionsStarted_ = false;
  31 };
  32
  33 remoting.ProtocolExtensionManager.prototype.dispose = function() {
  34   this.sendExtensionMessage_ = base.doNothing;
  35   this.protocolExtensions_ = {};
  36 };
  37
  38 /** Called by the plugin when the session is connected */
  39 remoting.ProtocolExtensionManager.prototype.start = function() {
  40   console.assert(!this.protocolExtensionsStarted_,
  41                  'Duplicate start() invocation.');
  42   /** @type {Object<remoting.ProtocolExtension, boolean>} */
  43   var started = {};
  44   for (var type in this.protocolExtensions_) {
  45     var extension = this.protocolExtensions_[type];
  46     if (!(extension in started)) {
  47       extension.startExtension(this.sendExtensionMessage_);
  48       started[extension] = true;
  49     }
  50   }
  51   this.protocolExtensionsStarted_ = true;
  52 };
  53
  54 /**
  55  * @param {remoting.ProtocolExtension} extension
  56  * @return {boolean} true if the extension is successfully registered.
  57  */
  58 remoting.ProtocolExtensionManager.prototype.register =
  59     function(extension) {
  60   var types = extension.getExtensionTypes();
  61
  62   // Make sure we don't have an extension of that type already registered.
  63   for (var i=0, len=types.length; i < len; i++) {
  64     if (types[i] in this.protocolExtensions_) {
  65       console.error(
  66           'Attempt to register multiple extensions of the same type: ', type);
  67       return false;
  68     }
  69   }
  70
  71   // Register the extension for each type.
  72   for (var i=0, len=types.length; i < len; i++) {
  73     var type = types[i];
  74     this.protocolExtensions_[type] = extension;
  75   }
  76
  77   // Start the extension.
  78   if (this.protocolExtensionsStarted_) {
  79     extension.startExtension(this.sendExtensionMessage_);
  80   }
  81
  82   return true;
  83 };
  84
  85 /**
  86  * Called when an extension message needs to be handled.
  87  *
  88  * @param {string} type The type of the extension message.
  89  * @param {string} data The payload of the extension message.
  90  * @return {boolean} Return true if the extension message was recognized.
  91  */
  92 remoting.ProtocolExtensionManager.prototype.onProtocolExtensionMessage =
  93     function(type, data) {
  94   if (type == 'test-echo-reply') {
  95     console.log('Got echo reply: ' + data);
  96     return true;
  97   }
  98
  99   var message = base.jsonParseSafe(data);
 100   if (typeof message != 'object') {
 101     console.error('Error parsing extension json data: ' + data);
 102     return false;
 103   }
 104
 105   if (type in this.protocolExtensions_) {
 106     /** @type {remoting.ProtocolExtension} */
 107     var extension = this.protocolExtensions_[type];
 108     var handled = false;
 109     try {
 110       handled = extension.onExtensionMessage(type, message);
 111     } catch (/** @type {*} */ err) {
 112       console.error('Failed to process protocol extension ' + type +
 113                     ' message: ' + err);
 114     }
 115     if (handled) {
 116       return true;
 117     }
 118   }
 119
 120   return false;
 121 };
 122
 123 })();