ios/web/web_state/js/resources/message.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 // Scripts for the message handler.
   6
   7 goog.provide('__crWeb.message');
   8
   9 goog.require('__crWeb.common');
  10 goog.require('__crWeb.messageDynamic');
  11
  12 /**
  13  * Namespace for this module.
  14  */
  15 __gCrWeb.message = {};
  16
  17 /* Beginning of anonymous object. */
  18 (function() {
  19   /**
  20    * Object to manage queue of messages waiting to be sent to the main
  21    * application for immediate processing.
  22    * @type {Object}
  23    * @private
  24    */
  25   var immediateMessageQueue_ = {
  26     scheme: 'crwebinvokeimmediate',
  27     reset: function() {
  28       immediateMessageQueue_.queue = [];
  29       // Since the array will be JSON serialized, protect against non-standard
  30       // custom versions of Array.prototype.toJSON.
  31       immediateMessageQueue_.queue.toJSON = null;
  32     }
  33   };
  34   immediateMessageQueue_.reset();
  35
  36   /**
  37    * Object to manage queue of messages waiting to be sent to the main
  38    * application for asynchronous processing.
  39    * @type {Object}
  40    * @private
  41    */
  42   var messageQueue_ = {
  43     scheme: 'crwebinvoke',
  44     reset: function() {
  45       messageQueue_.queue = [];
  46       // Since the array will be JSON serialized, protect against non-standard
  47       // custom versions of Array.prototype.toJSON.
  48       messageQueue_.queue.toJSON = null
  49     }
  50   };
  51   messageQueue_.reset();
  52
  53   /**
  54    * Invokes a command immediately on the Objective-C side.
  55    * An immediate command is a special class of command that must be handled at
  56    * the earliest opportunity. See the notes in CRWWebController for
  57    * restrictions and precautions.
  58    * @param {Object} command The command in a JavaScript object.
  59    * @private
  60    */
  61   __gCrWeb.message.invokeOnHostImmediate = function(command) {
  62     // If there is no document or body, the command will be silently dropped.
  63     if (!document || !document.body)
  64       return;
  65     immediateMessageQueue_.queue.push(command);
  66     sendQueue_(immediateMessageQueue_);
  67   };
  68
  69   /**
  70    * Invokes a command on the Objective-C side.
  71    * @param {Object} command The command in a JavaScript object.
  72    * @private
  73    */
  74   __gCrWeb.message.invokeOnHost = function(command) {
  75     // Avoid infinite loops in sites that send messages as a side effect
  76     // of URL verification (e.g., due to logging in an XHR override).
  77     if (window.__gCrWeb_Verifying) {
  78       return;
  79     }
  80     messageQueue_.queue.push(command);
  81     sendQueue_(messageQueue_);
  82   };
  83
  84   /**
  85    * Returns the message queue as a string.
  86    * @return {string} The current message queue as a JSON string.
  87    */
  88   __gCrWeb.message.getMessageQueue = function() {
  89     var messageQueueString = __gCrWeb.common.JSONStringify(messageQueue_.queue);
  90     messageQueue_.reset()
  91     return messageQueueString;
  92   };
  93
  94   /**
  95    * Sends both queues if they contain messages.
  96    */
  97   __gCrWeb.message.invokeQueues = function() {
  98     if (immediateMessageQueue_.queue.length > 0)
  99       sendQueue_(immediateMessageQueue_);
 100     if (messageQueue_.queue.length > 0)
 101       sendQueue_(messageQueue_);
 102   };
 103
 104   function sendQueue_(queueObject) {
 105     // Do nothing if windowId has not been set.
 106     if (!__gCrWeb.windowIdObject || typeof __gCrWeb.windowId != 'string') {
 107       return;
 108     }
 109     // Some pages/plugins implement Object.prototype.toJSON, which can result
 110     // in serializing messageQueue_ to an invalid format.
 111     var originalObjectToJSON = Object.prototype.toJSON;
 112     if (originalObjectToJSON)
 113       delete Object.prototype.toJSON;
 114     __gCrWeb.message_dynamic.sendQueue(queueObject);
 115
 116     if (originalObjectToJSON) {
 117       // Restore Object.prototype.toJSON to prevent from breaking any
 118       // functionality on the page that depends on its custom implementation.
 119       Object.prototype.toJSON = originalObjectToJSON;
 120     }
 121   };
 122 }());