chrome/browser/resources/pdf/main.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  * Global PDFViewer object, accessible for testing.
   9  * @type Object
  10  */
  11 var viewer;
  12
  13
  14 (function() {
  15   /**
  16    * Stores any pending messages received which should be passed to the
  17    * PDFViewer when it is created.
  18    * @type Array
  19    */
  20   var pendingMessages = [];
  21
  22   /**
  23    * Handles events that are received prior to the PDFViewer being created.
  24    * @param {Object} message A message event received.
  25    */
  26   function handleScriptingMessage(message) {
  27     pendingMessages.push(message);
  28   }
  29
  30   /**
  31    * Initialize the global PDFViewer and pass any outstanding messages to it.
  32    * @param {Object} browserApi An object providing an API to the browser.
  33    */
  34   function initViewer(browserApi) {
  35     // PDFViewer will handle any messages after it is created.
  36     window.removeEventListener('message', handleScriptingMessage, false);
  37     viewer = new PDFViewer(browserApi);
  38     while (pendingMessages.length > 0)
  39       viewer.handleScriptingMessage(pendingMessages.shift());
  40   }
  41
  42   /**
  43    * Entrypoint for starting the PDF viewer. This function obtains the browser
  44    * API for the PDF and constructs a PDFViewer object with it.
  45    */
  46   function main() {
  47     // Set up an event listener to catch scripting messages which are sent prior
  48     // to the PDFViewer being created.
  49     window.addEventListener('message', handleScriptingMessage, false);
  50
  51     createBrowserApi().then(initViewer);
  52   };
  53
  54   main();
  55 })();