Add m-esr52 at 52.6.0

1 files changed, 495 insertions, 0 deletions

diff --git a/toolkit/components/thumbnails/BackgroundPageThumbs.jsm b/toolkit/components/thumbnails/BackgroundPageThumbs.jsm
new file mode 100644
index 000000000..fded51cea
--- /dev/null
+++ b/toolkit/components/thumbnails/BackgroundPageThumbs.jsm
@@ -0,0 +1,495 @@
+/* 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_";
+
+const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+const HTML_NS = "http://www.w3.org/1999/xhtml";
+
+const ABOUT_NEWTAB_SEGREGATION_PREF = "privacy.usercontext.about_newtab_segregation.enabled";
+
+const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
+Cu.import("resource://gre/modules/PageThumbs.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
+
+// 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 TEL_CAPTURE_DONE_BAD_URI = 5;
+
+// These are looked up on the global as properties below.
+XPCOMUtils.defineConstant(this, "TEL_CAPTURE_DONE_OK", TEL_CAPTURE_DONE_OK);
+XPCOMUtils.defineConstant(this, "TEL_CAPTURE_DONE_TIMEOUT", TEL_CAPTURE_DONE_TIMEOUT);
+XPCOMUtils.defineConstant(this, "TEL_CAPTURE_DONE_CRASHED", TEL_CAPTURE_DONE_CRASHED);
+XPCOMUtils.defineConstant(this, "TEL_CAPTURE_DONE_BAD_URI", TEL_CAPTURE_DONE_BAD_URI);
+
+XPCOMUtils.defineLazyModuleGetter(this, "ContextualIdentityService",
+                                  "resource://gre/modules/ContextualIdentityService.jsm");
+const global = this;
+
+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.
+   * @return {Promise} A Promise that resolves when this task completes
+   */
+  captureIfMissing: Task.async(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.
+    let exists = yield PageThumbsStorage.fileExistsForURL(url);
+    if (exists) {
+      if (options.onDone) {
+        options.onDone(url);
+      }
+      return url;
+    }
+    let thumbPromise = new Promise((resolve, reject) => {
+      function observe(subject, topic, data) { // jshint ignore:line
+        if (data === url) {
+          switch (topic) {
+            case "page-thumbnail:create":
+              resolve();
+              break;
+            case "page-thumbnail:error":
+              reject(new Error("page-thumbnail:error"));
+              break;
+          }
+          Services.obs.removeObserver(observe, "page-thumbnail:create");
+          Services.obs.removeObserver(observe, "page-thumbnail:error");
+        }
+      }
+      Services.obs.addObserver(observe, "page-thumbnail:create", false);
+      Services.obs.addObserver(observe, "page-thumbnail:error", false);
+    });
+    try {
+      this.capture(url, options);
+      yield thumbPromise;
+    } catch (err) {
+      if (options.onDone) {
+        options.onDone(url);
+      }
+      throw err;
+    }
+    return url;
+  }),
+
+  /**
+   * Tell the service that the thumbnail browser should be recreated at next
+   * call of _ensureBrowser().
+   */
+  renewThumbnailBrowser: function() {
+    this._renewThumbBrowser = true;
+  },
+
+  /**
+   * 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 && !this._renewThumbBrowser)
+      return;
+
+    this._destroyBrowser();
+    this._renewThumbBrowser = false;
+
+    let browser = this._parentWin.document.createElementNS(XUL_NS, "browser");
+    browser.setAttribute("type", "content");
+    browser.setAttribute("remote", "true");
+    browser.setAttribute("disableglobalhistory", "true");
+
+    if (Services.prefs.getBoolPref(ABOUT_NEWTAB_SEGREGATION_PREF)) {
+      // Use the private container for thumbnails.
+      let privateIdentity =
+        ContextualIdentityService.getPrivateIdentity("userContextIdInternal.thumbnail");
+      browser.setAttribute("usercontextid", privateIdentity.userContextId);
+    }
+
+    // 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) {
+        // Continue queue processing by calling curCapture._done().  Do it after
+        // this crashed listener returns, though.  A new browser will be created
+        // immediately (on the same stack as the _done call stack) if there are
+        // any more queued-up captures, and that seems to mess up the new
+        // browser's message manager if it happens on the same stack as the
+        // listener.  Trying to send a message to the manager in that case
+        // throws NS_ERROR_NOT_INITIALIZED.
+        Services.tm.currentThread.dispatch(() => {
+          curCapture._done(null, TEL_CAPTURE_DONE_CRASHED);
+        }, Ci.nsIEventTarget.DISPATCH_NORMAL);
+      }
+      // 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);
+    if (capture.doneReason != TEL_CAPTURE_DONE_OK) {
+      Services.obs.notifyObservers(null, "page-thumbnail:error", 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,
+};
+
+Services.prefs.addObserver(ABOUT_NEWTAB_SEGREGATION_PREF,
+  function(aSubject, aTopic, aData) {
+    if (aTopic == "nsPref:changed" && aData == ABOUT_NEWTAB_SEGREGATION_PREF) {
+      BackgroundPageThumbs.renewThumbnailBrowser();
+    }
+  },
+  false);
+
+Object.defineProperty(this, "BackgroundPageThumbs", {
+  value: BackgroundPageThumbs,
+  enumerable: true,
+  writable: false
+});
+
+/**
+ * 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 = [];
+  this.doneReason;
+  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) {
+    if (msg.data.imageData)
+      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.data.id != this.id)
+      return;
+
+    if (msg.data.failReason) {
+      let reason = global["TEL_CAPTURE_DONE_" + msg.data.failReason];
+      this._done(null, reason);
+      return;
+    }
+
+    this._done(msg.data, 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();
+    this.doneReason = reason;
+
+    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 (Services.prefs.getBoolPref(ABOUT_NEWTAB_SEGREGATION_PREF)) {
+        // Clear the data in the private container for thumbnails.
+        let privateIdentity =
+          ContextualIdentityService.getPrivateIdentity("userContextIdInternal.thumbnail");
+        Services.obs.notifyObservers(null, "clear-origin-attributes-data",
+          JSON.stringify({ userContextId: privateIdentity.userContextId }));
+      }
+    };
+
+    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);
+}