chrome/browser/resources/pdf/browser_api.js

   1 // Copyright 2015 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  * Returns a promise that will resolve to the default zoom factor.
   9  * @param {!Object} streamInfo The stream object pointing to the data contained
  10  *     in the PDF.
  11  * @return {Promise<number>} A promise that will resolve to the default zoom
  12  *     factor.
  13  */
  14 function lookupDefaultZoom(streamInfo) {
  15   // Webviews don't run in tabs so |streamInfo.tabId| is -1 when running within
  16   // a webview.
  17   if (!chrome.tabs || streamInfo.tabId < 0)
  18     return Promise.resolve(1);
  19
  20   return new Promise(function(resolve, reject) {
  21     chrome.tabs.getZoomSettings(streamInfo.tabId, function(zoomSettings) {
  22       resolve(zoomSettings.defaultZoomFactor);
  23     });
  24   });
  25 }
  26
  27 /**
  28  * Returns a promise that will resolve to the initial zoom factor
  29  * upon starting the plugin. This may differ from the default zoom
  30  * if, for example, the page is zoomed before the plugin is run.
  31  * @param {!Object} streamInfo The stream object pointing to the data contained
  32  *     in the PDF.
  33  * @return {Promise<number>} A promise that will resolve to the initial zoom
  34  *     factor.
  35  */
  36 function lookupInitialZoom(streamInfo) {
  37   // Webviews don't run in tabs so |streamInfo.tabId| is -1 when running within
  38   // a webview.
  39   if (!chrome.tabs || streamInfo.tabId < 0)
  40     return Promise.resolve(1);
  41
  42   return new Promise(function(resolve, reject) {
  43     chrome.tabs.getZoom(streamInfo.tabId, resolve);
  44   });
  45 }
  46
  47 /**
  48  * A class providing an interface to the browser.
  49  */
  50 class BrowserApi {
  51   /**
  52    * @constructor
  53    * @param {!Object} streamInfo The stream object which points to the data
  54    *     contained in the PDF.
  55    * @param {number} defaultZoom The default browser zoom.
  56    * @param {number} initialZoom The initial browser zoom
  57    *     upon starting the plugin.
  58    * @param {boolean} manageZoom Whether to manage zoom.
  59    */
  60   constructor(streamInfo, defaultZoom, initialZoom, manageZoom) {
  61     this.streamInfo_ = streamInfo;
  62     this.defaultZoom_ = defaultZoom;
  63     this.initialZoom_ = initialZoom;
  64     this.manageZoom_ = manageZoom;
  65   }
  66
  67   /**
  68    * Returns a promise to a BrowserApi.
  69    * @param {!Object} streamInfo The stream object pointing to the data
  70    *     contained in the PDF.
  71    * @param {boolean} manageZoom Whether to manage zoom.
  72    */
  73   static create(streamInfo, manageZoom) {
  74     return Promise.all([
  75         lookupDefaultZoom(streamInfo),
  76         lookupInitialZoom(streamInfo)
  77     ]).then(function(zoomFactors) {
  78       return new BrowserApi(
  79           streamInfo, zoomFactors[0], zoomFactors[1], manageZoom);
  80     });
  81   }
  82
  83   /**
  84    * Returns the stream info pointing to the data contained in the PDF.
  85    * @return {Object} The stream info object.
  86    */
  87   getStreamInfo() {
  88     return this.streamInfo_;
  89   }
  90
  91   /**
  92    * Aborts the stream.
  93    */
  94   abortStream() {
  95     if (chrome.mimeHandlerPrivate)
  96       chrome.mimeHandlerPrivate.abortStream();
  97   }
  98
  99   /**
 100    * Sets the browser zoom.
 101    * @param {number} zoom The zoom factor to send to the browser.
 102    * @return {Promise} A promise that will be resolved when the browser zoom
 103    *     has been updated.
 104    */
 105   setZoom(zoom) {
 106     if (!this.manageZoom_)
 107       return Promise.resolve();
 108     return new Promise(function(resolve, reject) {
 109       chrome.tabs.setZoom(this.streamInfo_.tabId, zoom, resolve);
 110     }.bind(this));
 111   }
 112
 113   /**
 114    * Returns the default browser zoom factor.
 115    * @return {number} The default browser zoom factor.
 116    */
 117   getDefaultZoom() {
 118     return this.defaultZoom_;
 119   }
 120
 121   /**
 122    * Returns the initial browser zoom factor.
 123    * @return {number} The initial browser zoom factor.
 124    */
 125   getInitialZoom() {
 126     return this.initialZoom_;
 127   }
 128
 129   /**
 130    * Adds an event listener to be notified when the browser zoom changes.
 131    * @param {function} listener The listener to be called with the new zoom
 132    *     factor.
 133    */
 134   addZoomEventListener(listener) {
 135     if (!this.manageZoom_)
 136       return;
 137
 138     chrome.tabs.onZoomChange.addListener(function(zoomChangeInfo) {
 139       if (zoomChangeInfo.tabId != this.streamInfo_.tabId)
 140         return;
 141       listener(zoomChangeInfo.newZoomFactor);
 142     }.bind(this));
 143   }
 144 };
 145
 146 /**
 147  * Creates a BrowserApi for an extension running as a mime handler.
 148  * @return {Promise<BrowserApi>} A promise to a BrowserApi instance constructed
 149  *     using the mimeHandlerPrivate API.
 150  */
 151 function createBrowserApiForMimeHandlerView() {
 152   return new Promise(function(resolve, reject) {
 153     chrome.mimeHandlerPrivate.getStreamInfo(resolve);
 154   }).then(function(streamInfo) {
 155     let manageZoom = !streamInfo.embedded && streamInfo.tabId != -1;
 156     return new Promise(function(resolve, reject) {
 157       if (!manageZoom) {
 158         resolve();
 159         return;
 160       }
 161       chrome.tabs.setZoomSettings(
 162           streamInfo.tabId, {mode: 'manual', scope: 'per-tab'}, resolve);
 163     }).then(function() { return BrowserApi.create(streamInfo, manageZoom); });
 164   });
 165 }
 166
 167 /**
 168  * Creates a BrowserApi instance for an extension not running as a mime handler.
 169  * @return {Promise<BrowserApi>} A promise to a BrowserApi instance constructed
 170  *     from the URL.
 171  */
 172 function createBrowserApiForStandaloneExtension() {
 173   let url = window.location.search.substring(1);
 174   let streamInfo = {
 175     streamUrl: url,
 176     originalUrl: url,
 177     responseHeaders: {},
 178     embedded: window.parent != window,
 179     tabId: -1,
 180   };
 181   return new Promise(function(resolve, reject) {
 182     if (!chrome.tabs) {
 183       resolve();
 184       return;
 185     }
 186     chrome.tabs.getCurrent(function(tab) {
 187       streamInfo.tabId = tab.id;
 188       resolve();
 189     });
 190   }).then(function() { return BrowserApi.create(streamInfo, false); });
 191 }
 192
 193 /**
 194  * Returns a promise that will resolve to a BrowserApi instance.
 195  * @return {Promise<BrowserApi>} A promise to a BrowserApi instance for the
 196  *     current environment.
 197  */
 198 function createBrowserApi() {
 199   if (window.location.search)
 200     return createBrowserApiForStandaloneExtension();
 201
 202   return createBrowserApiForMimeHandlerView();
 203 }