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<string,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   base.debug.assert(!this.protocolExtensionsStarted_);
  41   /** @type {Object<remoting.ProtocolExtension, boolean>} */
  42   var started = {};
  43   for (var type in this.protocolExtensions_) {
  44     var extension = this.protocolExtensions_[type];
  45     if (!(extension in started)) {
  46       extension.startExtension(this.sendExtensionMessage_);
  47       started[extension] = true;
  48     }
  49   }
  50   this.protocolExtensionsStarted_ = true;
  51 };
  52
  53 /**
  54  * @param {remoting.ProtocolExtension} extension
  55  * @return {boolean} true if the extension is successfully registered.
  56  */
  57 remoting.ProtocolExtensionManager.prototype.register =
  58     function(extension) {
  59   var types = extension.getExtensionTypes();
  60
  61   // Make sure we don't have an extension of that type already registered.
  62   for (var i=0, len=types.length; i < len; i++) {
  63     if (types[i] in this.protocolExtensions_) {
  64       console.error(
  65           'Attempt to register multiple extensions of the same type: ', type);
  66       return false;
  67     }
  68   }
  69
  70   // Register the extension for each type.
  71   for (var i=0, len=types.length; i < len; i++) {
  72     var type = types[i];
  73     this.protocolExtensions_[type] = extension;
  74   }
  75
  76   // Start the extension.
  77   if (this.protocolExtensionsStarted_) {
  78     extension.startExtension(this.sendExtensionMessage_);
  79   }
  80
  81   return true;
  82 };
  83
  84 /**
  85  * Called when an extension message needs to be handled.
  86  *
  87  * @param {string} type The type of the extension message.
  88  * @param {string} data The payload of the extension message.
  89  * @return {boolean} Return true if the extension message was recognized.
  90  */
  91 remoting.ProtocolExtensionManager.prototype.onProtocolExtensionMessage =
  92     function(type, data) {
  93   if (type == 'test-echo-reply') {
  94     console.log('Got echo reply: ' + data);
  95     return true;
  96   }
  97
  98   var message = base.jsonParseSafe(data);
  99   if (typeof message != 'object') {
 100     console.error('Error parsing extension json data: ' + data);
 101     return false;
 102   }
 103
 104   if (type in this.protocolExtensions_) {
 105     /** @type {remoting.ProtocolExtension} */
 106     var extension = this.protocolExtensions_[type];
 107     var handled = false;
 108     try {
 109       handled = extension.onExtensionMessage(type, message);
 110     } catch (/** @type {*} */ err) {
 111       console.error('Failed to process protocol extension ' + type +
 112                     ' message: ' + err);
 113     }
 114     if (handled) {
 115       return true;
 116     }
 117   }
 118
 119   return false;
 120 };
 121
 122 })();