chrome/browser/resources/pdf/pdf_scripting_api.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 /**
   6  * Create a new PDFScriptingAPI. This provides a scripting interface to
   7  * the PDF viewer so that it can be customized by things like print preview.
   8  * @param {Window} window the window of the page containing the pdf viewer.
   9  * @param {string} extensionUrl the url of the PDF extension.
  10  */
  11 function PDFScriptingAPI(window, extensionUrl) {
  12   this.extensionUrl_ = extensionUrl;
  13   this.messageQueue_ = [];
  14   window.addEventListener('message', function(event) {
  15     if (event.origin != this.extensionUrl_) {
  16       console.error('Received message that was not from the extension: ' +
  17                     event);
  18       return;
  19     }
  20     switch (event.data.type) {
  21       case 'readyToReceive':
  22         this.setDestinationWindow(event.source);
  23         break;
  24       case 'viewport':
  25         if (this.viewportChangedCallback_)
  26           this.viewportChangedCallback_(event.data.pageX,
  27                                         event.data.pageY,
  28                                         event.data.pageWidth,
  29                                         event.data.viewportWidth,
  30                                         event.data.viewportHeight);
  31         break;
  32       case 'documentLoaded':
  33         if (this.loadCallback_)
  34           this.loadCallback_();
  35         break;
  36       case 'getAccessibilityJSONReply':
  37         if (this.accessibilityCallback_) {
  38           this.accessibilityCallback_(event.data.json);
  39           this.accessibilityCallback_ = null;
  40         }
  41         break;
  42     }
  43   }.bind(this), false);
  44 }
  45
  46 PDFScriptingAPI.prototype = {
  47   /**
  48    * @private
  49    * Send a message to the extension. If we try to send messages prior to the
  50    * extension being ready to receive messages (i.e. before it has finished
  51    * loading) we queue up the messages and flush them later.
  52    * @param {Object} message The message to send.
  53    */
  54   sendMessage_: function(message) {
  55     if (!this.pdfWindow_) {
  56       this.messageQueue_.push(message);
  57       return;
  58     }
  59
  60     this.pdfWindow_.postMessage(message, this.extensionUrl_);
  61   },
  62
  63   /**
  64    * Sets the destination window containing the PDF viewer. This will be called
  65    * when a 'readyToReceive' message is received from the PDF viewer or it can
  66    * be called during tests. It then flushes any pending messages to the window.
  67    * @param {Window} pdfWindow the window containing the PDF viewer.
  68    */
  69   setDestinationWindow: function(pdfWindow) {
  70     this.pdfWindow_ = pdfWindow;
  71     while (this.messageQueue_.length != 0) {
  72       this.pdfWindow_.postMessage(this.messageQueue_.shift(),
  73                                   this.extensionUrl_);
  74     }
  75   },
  76
  77   /**
  78    * Sets the callback which will be run when the PDF viewport changes.
  79    * @param {Function} callback the callback to be called.
  80    */
  81   setViewportChangedCallback: function(callback) {
  82     this.viewportChangedCallback_ = callback;
  83   },
  84
  85   /**
  86    * Sets the callback which will be run when the PDF document has finished
  87    * loading.
  88    * @param {Function} callback the callback to be called.
  89    */
  90   setLoadCallback: function(callback) {
  91     this.loadCallback_ = callback;
  92   },
  93
  94   /**
  95    * Resets the PDF viewer into print preview mode.
  96    * @param {string} url the url of the PDF to load.
  97    * @param {boolean} grayscale whether or not to display the PDF in grayscale.
  98    * @param {Array.<number>} pageNumbers an array of the page numbers.
  99    * @param {boolean} modifiable whether or not the document is modifiable.
 100    */
 101   resetPrintPreviewMode: function(url, grayscale, pageNumbers, modifiable) {
 102     this.sendMessage_({
 103       type: 'resetPrintPreviewMode',
 104       url: url,
 105       grayscale: grayscale,
 106       pageNumbers: pageNumbers,
 107       modifiable: modifiable
 108     });
 109   },
 110
 111   /**
 112    * Load a page into the document while in print preview mode.
 113    * @param {string} url the url of the pdf page to load.
 114    * @param {number} index the index of the page to load.
 115    */
 116   loadPreviewPage: function(url, index) {
 117     this.sendMessage_({
 118       type: 'loadPreviewPage',
 119       url: url,
 120       index: index
 121     });
 122   },
 123
 124   /**
 125    * Get accessibility JSON for the document.
 126    * @param {Function} callback a callback to be called with the accessibility
 127    *     json that has been retrieved.
 128    * @param {number} [page] the 0-indexed page number to get accessibility data
 129    *     for. If this is not provided, data about the entire document is
 130    *     returned.
 131    * @return {boolean} true if the function is successful, false if there is an
 132    *     outstanding request for accessibility data that has not been answered.
 133    */
 134   getAccessibilityJSON: function(callback, page) {
 135     if (this.accessibilityCallback_)
 136       return false;
 137     this.accessibilityCallback_ = callback;
 138     var message = {
 139       type: 'getAccessibilityJSON',
 140     };
 141     if (page || page == 0)
 142       message.page = page;
 143     this.sendMessage_(message);
 144     return true;
 145   },
 146
 147   /**
 148    * Send a key event to the extension.
 149    * @param {number} keyCode the key code to send to the extension.
 150    */
 151   sendKeyEvent: function(keyCode) {
 152     this.sendMessage_({
 153       type: 'sendKeyEvent',
 154       keyCode: keyCode
 155     });
 156   },
 157 };
 158
 159 /**
 160  * Creates a PDF viewer with a scripting interface. This is basically 1) an
 161  * iframe which is navigated to the PDF viewer extension and 2) a scripting
 162  * interface which provides access to various features of the viewer for use
 163  * by print preview and accessibility.
 164  * @param {string} src the source URL of the PDF to load initially.
 165  * @return {HTMLIFrameElement} the iframe element containing the PDF viewer.
 166  */
 167 function PDFCreateOutOfProcessPlugin(src) {
 168   var EXTENSION_URL = 'chrome-extension://mhjfbmdgcfjbbpaeojofohoefgiehjai';
 169   var iframe = window.document.createElement('iframe');
 170   iframe.setAttribute('src', EXTENSION_URL + '/index.html?' + src);
 171   var client = new PDFScriptingAPI(window, EXTENSION_URL);
 172
 173   // Add the functions to the iframe so that they can be called directly.
 174   iframe.setViewportChangedCallback =
 175       client.setViewportChangedCallback.bind(client);
 176   iframe.setLoadCallback = client.setLoadCallback.bind(client);
 177   iframe.resetPrintPreviewMode = client.resetPrintPreviewMode.bind(client);
 178   iframe.loadPreviewPage = client.loadPreviewPage.bind(client);
 179   iframe.sendKeyEvent = client.sendKeyEvent.bind(client);
 180   return iframe;
 181 }