chrome/browser/resources/whispernet_proxy/js/nacl.js

   1 // Copyright 2014 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 'use strict';
   6
   7 /**
   8  * Constructor for the Nacl bridge to the whispernet wrapper.
   9  * @param {string} nmf The relative path to the nmf containing the location of
  10  * the whispernet Nacl wrapper.
  11  * @param {function()} readyCallback Callback to be called once we've loaded the
  12  * whispernet wrapper.
  13  */
  14 function NaclBridge(nmf, readyCallback) {
  15   this.readyCallback_ = readyCallback;
  16   this.callbacks_ = [];
  17   this.isEnabled_ = false;
  18   this.naclId_ = this.loadNacl_(nmf);
  19 }
  20
  21 /**
  22  * Method to send generic byte data to the whispernet wrapper.
  23  * @param {Object} data Raw data to send to the whispernet wrapper.
  24  */
  25 NaclBridge.prototype.send = function(data) {
  26   if (this.isEnabled_) {
  27     this.embed_.postMessage(data);
  28   } else {
  29     console.error('Whisper Nacl Bridge not initialized!');
  30   }
  31 };
  32
  33 /**
  34  * Method to add a listener to Nacl messages received by this bridge.
  35  * @param {function(Event)} messageCallback Callback to receive the messsage.
  36  */
  37 NaclBridge.prototype.addListener = function(messageCallback) {
  38   this.callbacks_.push(messageCallback);
  39 };
  40
  41 /**
  42  * Method that receives Nacl messages and forwards them to registered
  43  * callbacks.
  44  * @param {Event} e Event from the whispernet wrapper.
  45  * @private
  46  */
  47 NaclBridge.prototype.onMessage_ = function(e) {
  48   if (this.isEnabled_) {
  49     this.callbacks_.forEach(function(callback) {
  50       callback(e);
  51     });
  52   }
  53 };
  54
  55 /**
  56  * Injects the <embed> for this nacl manifest URL, generating a unique ID.
  57  * @param {string} manifestUrl Url to the nacl manifest to load.
  58  * @return {number} generated ID.
  59  * @private
  60  */
  61 NaclBridge.prototype.loadNacl_ = function(manifestUrl) {
  62   var id = 'nacl-' + Math.floor(Math.random() * 10000);
  63   this.embed_ = document.createElement('embed');
  64   this.embed_.name = 'nacl_module';
  65   this.embed_.width = 1;
  66   this.embed_.height = 1;
  67   this.embed_.src = manifestUrl;
  68   this.embed_.id = id;
  69   this.embed_.type = 'application/x-pnacl';
  70
  71   // Wait for the element to load and callback.
  72   this.embed_.addEventListener('load', this.onNaclReady_.bind(this));
  73   this.embed_.addEventListener('error', this.onNaclError_.bind(this));
  74
  75   // Inject the embed string into the page.
  76   document.body.appendChild(this.embed_);
  77
  78   // Listen for messages from the NaCl module.
  79   window.addEventListener('message', this.onMessage_.bind(this), true);
  80   return id;
  81 };
  82
  83 /**
  84  * Called when the Whispernet wrapper is loaded.
  85  * @private
  86  */
  87 NaclBridge.prototype.onNaclReady_ = function() {
  88   this.isEnabled_ = true;
  89   if (this.readyCallback_)
  90     this.readyCallback_();
  91 };
  92
  93 /**
  94  * Callback that handles Nacl errors.
  95  * @param {string} msg Error string.
  96  * @private
  97  */
  98 NaclBridge.prototype.onNaclError_ = function(msg) {
  99   // TODO(rkc): Handle error from NaCl better.
 100   console.error('NaCl error', msg);
 101 };