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  * Turn a dictionary received from postMessage into a key event.
   7  * @param {Object} dict A dictionary representing the key event.
   8  * @return {Event} A key event.
   9  */
  10 function DeserializeKeyEvent(dict) {
  11   var e = document.createEvent('Event');
  12   e.initEvent('keydown');
  13   e.keyCode = dict.keyCode;
  14   e.shiftKey = dict.shiftKey;
  15   e.ctrlKey = dict.ctrlKey;
  16   e.altKey = dict.altKey;
  17   e.metaKey = dict.metaKey;
  18   e.fromScriptingAPI = true;
  19   return e;
  20 }
  21
  22 /**
  23  * Turn a key event into a dictionary which can be sent over postMessage.
  24  * @param {Event} event A key event.
  25  * @return {Object} A dictionary representing the key event.
  26  */
  27 function SerializeKeyEvent(event) {
  28   return {
  29     keyCode: event.keyCode,
  30     shiftKey: event.shiftKey,
  31     ctrlKey: event.ctrlKey,
  32     altKey: event.altKey,
  33     metaKey: event.metaKey
  34   };
  35 }
  36
  37 /**
  38  * Create a new PDFScriptingAPI. This provides a scripting interface to
  39  * the PDF viewer so that it can be customized by things like print preview.
  40  * @param {Window} window the window of the page containing the pdf viewer.
  41  * @param {Object} plugin the plugin element containing the pdf viewer.
  42  */
  43 function PDFScriptingAPI(window, plugin) {
  44   this.loaded_ = false;
  45   this.pendingScriptingMessages_ = [];
  46   this.setPlugin(plugin);
  47
  48   window.addEventListener('message', function(event) {
  49     if (event.origin != 'chrome-extension://mhjfbmdgcfjbbpaeojofohoefgiehjai') {
  50       console.error('Received message that was not from the extension: ' +
  51                     event);
  52       return;
  53     }
  54     switch (event.data.type) {
  55       case 'viewport':
  56         if (this.viewportChangedCallback_)
  57           this.viewportChangedCallback_(event.data.pageX,
  58                                         event.data.pageY,
  59                                         event.data.pageWidth,
  60                                         event.data.viewportWidth,
  61                                         event.data.viewportHeight);
  62         break;
  63       case 'documentLoaded':
  64         this.loaded_ = true;
  65         if (this.loadCallback_)
  66           this.loadCallback_();
  67         break;
  68       case 'getAccessibilityJSONReply':
  69         if (this.accessibilityCallback_) {
  70           this.accessibilityCallback_(event.data.json);
  71           this.accessibilityCallback_ = null;
  72         }
  73         break;
  74       case 'getSelectedTextReply':
  75         if (this.selectedTextCallback_) {
  76           this.selectedTextCallback_(event.data.selectedText);
  77           this.selectedTextCallback_ = null;
  78         }
  79         break;
  80       case 'sendKeyEvent':
  81         if (this.keyEventCallback_)
  82           this.keyEventCallback_(DeserializeKeyEvent(event.data.keyEvent));
  83         break;
  84     }
  85   }.bind(this), false);
  86 }
  87
  88 PDFScriptingAPI.prototype = {
  89   /**
  90    * @private
  91    * Send a message to the extension. If messages try to get sent before there
  92    * is a plugin element set, then we queue them up and send them later (this
  93    * can happen in print preview).
  94    * @param {Object} message The message to send.
  95    */
  96   sendMessage_: function(message) {
  97     if (this.plugin_)
  98       this.plugin_.postMessage(message, '*');
  99     else
 100       this.pendingScriptingMessages_.push(message);
 101   },
 102
 103  /**
 104   * Sets the plugin element containing the PDF viewer. The element will usually
 105   * be passed into the PDFScriptingAPI constructor but may also be set later.
 106   * @param {Object} plugin the plugin element containing the PDF viewer.
 107   */
 108   setPlugin: function(plugin) {
 109     this.plugin_ = plugin;
 110
 111     if (this.plugin_) {
 112       // Send a message to ensure the postMessage channel is initialized which
 113       // allows us to receive messages.
 114       this.sendMessage_({
 115         type: 'initialize'
 116       });
 117       // Flush pending messages.
 118       while (this.pendingScriptingMessages_.length > 0)
 119         this.sendMessage_(this.pendingScriptingMessages_.shift());
 120     }
 121   },
 122
 123   /**
 124    * Sets the callback which will be run when the PDF viewport changes.
 125    * @param {Function} callback the callback to be called.
 126    */
 127   setViewportChangedCallback: function(callback) {
 128     this.viewportChangedCallback_ = callback;
 129   },
 130
 131   /**
 132    * Sets the callback which will be run when the PDF document has finished
 133    * loading. If the document is already loaded, it will be run immediately.
 134    * @param {Function} callback the callback to be called.
 135    */
 136   setLoadCallback: function(callback) {
 137     this.loadCallback_ = callback;
 138     if (this.loaded_ && this.loadCallback_)
 139       this.loadCallback_();
 140   },
 141
 142   /**
 143    * Sets a callback that gets run when a key event is fired in the PDF viewer.
 144    * @param {Function} callback the callback to be called with a key event.
 145    */
 146   setKeyEventCallback: function(callback) {
 147     this.keyEventCallback_ = callback;
 148   },
 149
 150   /**
 151    * Resets the PDF viewer into print preview mode.
 152    * @param {string} url the url of the PDF to load.
 153    * @param {boolean} grayscale whether or not to display the PDF in grayscale.
 154    * @param {Array<number>} pageNumbers an array of the page numbers.
 155    * @param {boolean} modifiable whether or not the document is modifiable.
 156    */
 157   resetPrintPreviewMode: function(url, grayscale, pageNumbers, modifiable) {
 158     this.loaded_ = false;
 159     this.sendMessage_({
 160       type: 'resetPrintPreviewMode',
 161       url: url,
 162       grayscale: grayscale,
 163       pageNumbers: pageNumbers,
 164       modifiable: modifiable
 165     });
 166   },
 167
 168   /**
 169    * Load a page into the document while in print preview mode.
 170    * @param {string} url the url of the pdf page to load.
 171    * @param {number} index the index of the page to load.
 172    */
 173   loadPreviewPage: function(url, index) {
 174     this.sendMessage_({
 175       type: 'loadPreviewPage',
 176       url: url,
 177       index: index
 178     });
 179   },
 180
 181   /**
 182    * Get accessibility JSON for the document. May only be called after document
 183    * load.
 184    * @param {Function} callback a callback to be called with the accessibility
 185    *     json that has been retrieved.
 186    * @param {number} [page] the 0-indexed page number to get accessibility data
 187    *     for. If this is not provided, data about the entire document is
 188    *     returned.
 189    * @return {boolean} true if the function is successful, false if there is an
 190    *     outstanding request for accessibility data that has not been answered.
 191    */
 192   getAccessibilityJSON: function(callback, page) {
 193     if (this.accessibilityCallback_)
 194       return false;
 195     this.accessibilityCallback_ = callback;
 196     var message = {
 197       type: 'getAccessibilityJSON',
 198     };
 199     if (page || page == 0)
 200       message.page = page;
 201     this.sendMessage_(message);
 202     return true;
 203   },
 204
 205   /**
 206    * Select all the text in the document. May only be called after document
 207    * load.
 208    */
 209   selectAll: function() {
 210     this.sendMessage_({
 211       type: 'selectAll'
 212     });
 213   },
 214
 215   /**
 216    * Get the selected text in the document. The callback will be called with the
 217    * text that is selected. May only be called after document load.
 218    * @param {Function} callback a callback to be called with the selected text.
 219    * @return {boolean} true if the function is successful, false if there is an
 220    *     outstanding request for selected text that has not been answered.
 221    */
 222   getSelectedText: function(callback) {
 223     if (this.selectedTextCallback_)
 224       return false;
 225     this.selectedTextCallback_ = callback;
 226     this.sendMessage_({
 227       type: 'getSelectedText'
 228     });
 229     return true;
 230   },
 231
 232   /**
 233    * Print the document. May only be called after document load.
 234    */
 235   print: function() {
 236     this.sendMessage_({
 237       type: 'print'
 238     });
 239   },
 240
 241   /**
 242    * Send a key event to the extension.
 243    * @param {Event} keyEvent the key event to send to the extension.
 244    */
 245   sendKeyEvent: function(keyEvent) {
 246     this.sendMessage_({
 247       type: 'sendKeyEvent',
 248       keyEvent: SerializeKeyEvent(keyEvent)
 249     });
 250   },
 251 };
 252
 253 var IS_MAC_PARAM = 'isMac&';
 254
 255 /**
 256  * Creates a PDF viewer with a scripting interface. This is basically 1) an
 257  * iframe which is navigated to the PDF viewer extension and 2) a scripting
 258  * interface which provides access to various features of the viewer for use
 259  * by print preview and accessibility.
 260  * @param {string} src the source URL of the PDF to load initially.
 261  * @return {HTMLIFrameElement} the iframe element containing the PDF viewer.
 262  */
 263 function PDFCreateOutOfProcessPlugin(src) {
 264   var iframe = window.document.createElement('iframe');
 265   var isMac = cr.isMac ? IS_MAC_PARAM : '';
 266   iframe.setAttribute(
 267       'src',
 268       'chrome-extension://mhjfbmdgcfjbbpaeojofohoefgiehjai/index.html?' +
 269       isMac + src);
 270   // Prevent the frame from being tab-focusable.
 271   iframe.setAttribute('tabindex', '-1');
 272   var client = new PDFScriptingAPI(window);
 273   iframe.onload = function() {
 274     client.setPlugin(iframe.contentWindow);
 275   };
 276   // Add the functions to the iframe so that they can be called directly.
 277   iframe.setViewportChangedCallback =
 278       client.setViewportChangedCallback.bind(client);
 279   iframe.setLoadCallback = client.setLoadCallback.bind(client);
 280   iframe.setKeyEventCallback = client.setKeyEventCallback.bind(client);
 281   iframe.resetPrintPreviewMode = client.resetPrintPreviewMode.bind(client);
 282   iframe.loadPreviewPage = client.loadPreviewPage.bind(client);
 283   iframe.sendKeyEvent = client.sendKeyEvent.bind(client);
 284   return iframe;
 285 }