The Tor Browser: toolkit/components/thumbnails/BackgroundPageThumbs.jsm@129ffea94266 (annotated)

toolkit/components/thumbnails/BackgroundPageThumbs.jsm@129ffea94266 (annotated)

toolkit/components/thumbnails/BackgroundPageThumbs.jsm

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 const EXPORTED_SYMBOLS = [
   "BackgroundPageThumbs",
 ];
 const DEFAULT_CAPTURE_TIMEOUT = 30000; // ms
 const DESTROY_BROWSER_TIMEOUT = 60000; // ms
 const FRAME_SCRIPT_URL = "chrome://global/content/backgroundPageThumbsContent.js";
 const TELEMETRY_HISTOGRAM_ID_PREFIX = "FX_THUMBNAILS_BG_";
 // possible FX_THUMBNAILS_BG_CAPTURE_DONE_REASON_2 telemetry values
 const TEL_CAPTURE_DONE_OK = 0;
 const TEL_CAPTURE_DONE_TIMEOUT = 1;
 // 2 and 3 were used when we had special handling for private-browsing.
 const TEL_CAPTURE_DONE_CRASHED = 4;
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
 Cu.import("resource://gre/modules/PageThumbs.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 const BackgroundPageThumbs = {
   /**
    * Asynchronously captures a thumbnail of the given URL.
    *
    * The page is loaded anonymously, and plug-ins are disabled.
    *
    * @param url      The URL to capture.
    * @param options  An optional object that configures the capture.  Its
    *                 properties are the following, and all are optional:
    * @opt onDone     A function that will be asynchronously called when the
    *                 capture is complete or times out.  It's called as
    *                   onDone(url),
    *                 where `url` is the captured URL.
    * @opt timeout    The capture will time out after this many milliseconds have
    *                 elapsed after the capture has progressed to the head of
    *                 the queue and started.  Defaults to 30000 (30 seconds).
    */
   capture: function (url, options={}) {
     if (!PageThumbs._prefEnabled()) {
       if (options.onDone)
         schedule(() => options.onDone(url));
       return;
     }
     this._captureQueue = this._captureQueue || [];
     this._capturesByURL = this._capturesByURL || new Map();
     tel("QUEUE_SIZE_ON_CAPTURE", this._captureQueue.length);
     // We want to avoid duplicate captures for the same URL.  If there is an
     // existing one, we just add the callback to that one and we are done.
     let existing = this._capturesByURL.get(url);
     if (existing) {
       if (options.onDone)
         existing.doneCallbacks.push(options.onDone);
       // The queue is already being processed, so nothing else to do...
       return;
     }
     let cap = new Capture(url, this._onCaptureOrTimeout.bind(this), options);
     this._captureQueue.push(cap);
     this._capturesByURL.set(url, cap);
     this._processCaptureQueue();
   },
   /**
    * Asynchronously captures a thumbnail of the given URL if one does not
    * already exist.  Otherwise does nothing.
    *
    * @param url      The URL to capture.
    * @param options  An optional object that configures the capture.  See
    *                 capture() for description.
    */
   captureIfMissing: function (url, options={}) {
     // The fileExistsForURL call is an optimization, potentially but unlikely
     // incorrect, and no big deal when it is.  After the capture is done, we
     // atomically test whether the file exists before writing it.
     PageThumbsStorage.fileExistsForURL(url).then(exists => {
       if (exists.ok) {
         if (options.onDone)
           options.onDone(url);
         return;
       }
       this.capture(url, options);
     }, err => {
       if (options.onDone)
         options.onDone(url);
     });
   },
   /**
    * Ensures that initialization of the thumbnail browser's parent window has
    * begun.
    *
    * @return  True if the parent window is completely initialized and can be
    *          used, and false if initialization has started but not completed.
    */
   _ensureParentWindowReady: function () {
     if (this._parentWin)
       // Already fully initialized.
       return true;
     if (this._startedParentWinInit)
       // Already started initializing.
       return false;
     this._startedParentWinInit = true;
     // Create an html:iframe, stick it in the parent document, and
     // use it to host the browser.  about:blank will not have the system
     // principal, so it can't host, but a document with a chrome URI will.
     let hostWindow = Services.appShell.hiddenDOMWindow;
     let iframe = hostWindow.document.createElementNS(HTML_NS, "iframe");
     iframe.setAttribute("src", "chrome://global/content/mozilla.xhtml");
     let onLoad = function onLoadFn() {
       iframe.removeEventListener("load", onLoad, true);
       this._parentWin = iframe.contentWindow;
       this._processCaptureQueue();
     }.bind(this);
     iframe.addEventListener("load", onLoad, true);
     hostWindow.document.documentElement.appendChild(iframe);
     this._hostIframe = iframe;
     return false;
   },
   /**
    * Destroys the service.  Queued and pending captures will never complete, and
    * their consumer callbacks will never be called.
    */
   _destroy: function () {
     if (this._captureQueue)
       this._captureQueue.forEach(cap => cap.destroy());
     this._destroyBrowser();
     if (this._hostIframe)
       this._hostIframe.remove();
     delete this._captureQueue;
     delete this._hostIframe;
     delete this._startedParentWinInit;
     delete this._parentWin;
   },
   /**
    * Creates the thumbnail browser if it doesn't already exist.
    */
   _ensureBrowser: function () {
     if (this._thumbBrowser)
       return;
     let browser = this._parentWin.document.createElementNS(XUL_NS, "browser");
     browser.setAttribute("type", "content");
     browser.setAttribute("remote", "true");
     // Size the browser.  Make its aspect ratio the same as the canvases' that
     // the thumbnails are drawn into; the canvases' aspect ratio is the same as
     // the screen's, so use that.  Aim for a size in the ballpark of 1024x768.
     let [swidth, sheight] = [{}, {}];
     Cc["@mozilla.org/gfx/screenmanager;1"].
       getService(Ci.nsIScreenManager).
       primaryScreen.
       GetRectDisplayPix({}, {}, swidth, sheight);
     let bwidth = Math.min(1024, swidth.value);
     // Setting the width and height attributes doesn't work -- the resulting
     // thumbnails are blank and transparent -- but setting the style does.
     browser.style.width = bwidth + "px";
     browser.style.height = (bwidth * sheight.value / swidth.value) + "px";
     this._parentWin.document.documentElement.appendChild(browser);
     // an event that is sent if the remote process crashes - no need to remove
     // it as we want it to be there as long as the browser itself lives.
     browser.addEventListener("oop-browser-crashed", () => {
       Cu.reportError("BackgroundThumbnails remote process crashed - recovering");
       this._destroyBrowser();
       let curCapture = this._captureQueue.length ? this._captureQueue[0] : null;
       // we could retry the pending capture, but it's possible the crash
       // was due directly to it, so trying again might just crash again.
       // We could keep a flag to indicate if it previously crashed, but
       // "resetting" the capture requires more work - so for now, we just
       // discard it.
       if (curCapture && curCapture.pending) {
         curCapture._done(null, TEL_CAPTURE_DONE_CRASHED);
         // _done automatically continues queue processing.
       }
       // else: we must have been idle and not currently doing a capture (eg,
       // maybe a GC or similar crashed) - so there's no need to attempt a
       // queue restart - the next capture request will set everything up.
     });
     browser.messageManager.loadFrameScript(FRAME_SCRIPT_URL, false);
     this._thumbBrowser = browser;
   },
   _destroyBrowser: function () {
     if (!this._thumbBrowser)
       return;
     this._thumbBrowser.remove();
     delete this._thumbBrowser;
   },
   /**
    * Starts the next capture if the queue is not empty and the service is fully
    * initialized.
    */
   _processCaptureQueue: function () {
     if (!this._captureQueue.length ||
         this._captureQueue[0].pending ||
         !this._ensureParentWindowReady())
       return;
     // Ready to start the first capture in the queue.
     this._ensureBrowser();
     this._captureQueue[0].start(this._thumbBrowser.messageManager);
     if (this._destroyBrowserTimer) {
       this._destroyBrowserTimer.cancel();
       delete this._destroyBrowserTimer;
     }
   },
   /**
    * Called when the current capture completes or fails (eg, times out, remote
    * process crashes.)
    */
   _onCaptureOrTimeout: function (capture) {
     // Since timeouts start as an item is being processed, only the first
     // item in the queue can be passed to this method.
     if (capture !== this._captureQueue[0])
       throw new Error("The capture should be at the head of the queue.");
     this._captureQueue.shift();
     this._capturesByURL.delete(capture.url);
     // Start the destroy-browser timer *before* processing the capture queue.
     let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
     timer.initWithCallback(this._destroyBrowser.bind(this),
                            this._destroyBrowserTimeout,
                            Ci.nsITimer.TYPE_ONE_SHOT);
     this._destroyBrowserTimer = timer;
     this._processCaptureQueue();
   },
   _destroyBrowserTimeout: DESTROY_BROWSER_TIMEOUT,
 };
 /**
  * Represents a single capture request in the capture queue.
  *
  * @param url              The URL to capture.
  * @param captureCallback  A function you want called when the capture
  *                         completes.
  * @param options          The capture options.
  */
 function Capture(url, captureCallback, options) {
   this.url = url;
   this.captureCallback = captureCallback;
   this.options = options;
   this.id = Capture.nextID++;
   this.creationDate = new Date();
   this.doneCallbacks = [];
   if (options.onDone)
     this.doneCallbacks.push(options.onDone);
 }
 Capture.prototype = {
   get pending() {
     return !!this._msgMan;
   },
   /**
    * Sends a message to the content script to start the capture.
    *
    * @param messageManager  The nsIMessageSender of the thumbnail browser.
    */
   start: function (messageManager) {
     this.startDate = new Date();
     tel("CAPTURE_QUEUE_TIME_MS", this.startDate - this.creationDate);
     // timeout timer
     let timeout = typeof(this.options.timeout) == "number" ?
                   this.options.timeout :
                   DEFAULT_CAPTURE_TIMEOUT;
     this._timeoutTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
     this._timeoutTimer.initWithCallback(this, timeout,
                                         Ci.nsITimer.TYPE_ONE_SHOT);
     // didCapture registration
     this._msgMan = messageManager;
     this._msgMan.sendAsyncMessage("BackgroundPageThumbs:capture",
                                   { id: this.id, url: this.url });
     this._msgMan.addMessageListener("BackgroundPageThumbs:didCapture", this);
   },
   /**
    * The only intended external use of this method is by the service when it's
    * uninitializing and doing things like destroying the thumbnail browser.  In
    * that case the consumer's completion callback will never be called.
    */
   destroy: function () {
     // This method may be called for captures that haven't started yet, so
     // guard against not yet having _timeoutTimer, _msgMan etc properties...
     if (this._timeoutTimer) {
       this._timeoutTimer.cancel();
       delete this._timeoutTimer;
     }
     if (this._msgMan) {
       this._msgMan.removeMessageListener("BackgroundPageThumbs:didCapture",
                                          this);
       delete this._msgMan;
     }
     delete this.captureCallback;
     delete this.doneCallbacks;
     delete this.options;
   },
   // Called when the didCapture message is received.
   receiveMessage: function (msg) {
     tel("CAPTURE_SERVICE_TIME_MS", new Date() - this.startDate);
     // A different timed-out capture may have finally successfully completed, so
     // discard messages that aren't meant for this capture.
     if (msg.json.id == this.id)
       this._done(msg.json, TEL_CAPTURE_DONE_OK);
   },
   // Called when the timeout timer fires.
   notify: function () {
     this._done(null, TEL_CAPTURE_DONE_TIMEOUT);
   },
   _done: function (data, reason) {
     // Note that _done will be called only once, by either receiveMessage or
     // notify, since it calls destroy here, which cancels the timeout timer and
     // removes the didCapture message listener.
     let { captureCallback, doneCallbacks, options } = this;
     this.destroy();
     if (typeof(reason) != "number")
       throw new Error("A done reason must be given.");
     tel("CAPTURE_DONE_REASON_2", reason);
     if (data && data.telemetry) {
       // Telemetry is currently disabled in the content process (bug 680508).
       for (let id in data.telemetry) {
         tel(id, data.telemetry[id]);
       }
     }
     let done = () => {
       captureCallback(this);
       for (let callback of doneCallbacks) {
         try {
           callback.call(options, this.url);
         }
         catch (err) {
           Cu.reportError(err);
         }
       }
     };
     if (!data) {
       done();
       return;
     }
     PageThumbs._store(this.url, data.finalURL, data.imageData, true)
               .then(done, done);
   },
 };
 Capture.nextID = 0;
 /**
  * Adds a value to one of this module's telemetry histograms.
  *
  * @param histogramID  This is prefixed with this module's ID.
  * @param value        The value to add.
  */
 function tel(histogramID, value) {
   let id = TELEMETRY_HISTOGRAM_ID_PREFIX + histogramID;
   Services.telemetry.getHistogramById(id).add(value);
 }
 function schedule(callback) {
   Services.tm.mainThread.dispatch(callback, Ci.nsIThread.DISPATCH_NORMAL);
 }

The Tor Browser / annotate

toolkit/components/thumbnails/BackgroundPageThumbs.jsm@129ffea94266 (annotated)

toolkit/components/thumbnails/BackgroundPageThumbs.jsm