The Tor Browser: browser/modules/CustomizationTabPreloader.jsm@b8a032363ba2 (annotated)

browser/modules/CustomizationTabPreloader.jsm@b8a032363ba2 (annotated)

browser/modules/CustomizationTabPreloader.jsm

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* 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/. */
 "use strict";
 this.EXPORTED_SYMBOLS = ["CustomizationTabPreloader"];
 const Cu = Components.utils;
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/Promise.jsm");
 const HTML_NS = "http://www.w3.org/1999/xhtml";
 const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
 const XUL_PAGE = "data:application/vnd.mozilla.xul+xml;charset=utf-8,<window%20id='win'/>";
 const CUSTOMIZATION_URL = "about:customizing";
 // The interval between swapping in a preload docShell and kicking off the
 // next preload in the background.
 const PRELOADER_INTERVAL_MS = 600;
 function createTimer(obj, delay) {
   let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
   timer.init(obj, delay, Ci.nsITimer.TYPE_ONE_SHOT);
   return timer;
 }
 function clearTimer(timer) {
   if (timer) {
     timer.cancel();
   }
   return null;
 }
 this.CustomizationTabPreloader = {
   uninit: function () {
     CustomizationTabPreloaderInternal.uninit();
   },
   newTab: function (aTab) {
     return CustomizationTabPreloaderInternal.newTab(aTab);
   },
   /**
    * ensurePreloading starts the preloading of the about:customizing
    * content page. This function is idempotent (until a call to uninit),
    * so multiple calls to it are fine.
    */
   ensurePreloading: function() {
     CustomizationTabPreloaderInternal.ensurePreloading();
   },
 };
 Object.freeze(CustomizationTabPreloader);
 this.CustomizationTabPreloaderInternal = {
   _browser: null,
   uninit: function () {
     HostFrame.destroy();
     if (this._browser) {
       this._browser.destroy();
       this._browser = null;
     }
   },
   newTab: function (aTab) {
     let win = aTab.ownerDocument.defaultView;
     if (win.gBrowser && this._browser) {
       return this._browser.swapWithNewTab(aTab);
     }
     return false;
   },
   ensurePreloading: function () {
     if (!this._browser) {
       this._browser = new HiddenBrowser();
     }
   }
 };
 function HiddenBrowser() {
   this._createBrowser();
 }
 HiddenBrowser.prototype = {
   _timer: null,
   get isPreloaded() {
     return this._browser &&
            this._browser.contentDocument &&
            this._browser.contentDocument.readyState === "complete" &&
            this._browser.currentURI.spec === CUSTOMIZATION_URL;
   },
   swapWithNewTab: function (aTab) {
     if (!this.isPreloaded || this._timer) {
       return false;
     }
     let win = aTab.ownerDocument.defaultView;
     let tabbrowser = win.gBrowser;
     if (!tabbrowser) {
       return false;
     }
     // Swap docShells.
     tabbrowser.swapNewTabWithBrowser(aTab, this._browser);
     // Load all default frame scripts attached to the target window.
     let mm = aTab.linkedBrowser.messageManager;
     let scripts = win.messageManager.getDelayedFrameScripts();
     Array.forEach(scripts, ([script, runGlobal]) => mm.loadFrameScript(script, true, runGlobal));
     // Remove the browser, it will be recreated by a timer.
     this._removeBrowser();
     // Start a timer that will kick off preloading the next page.
     this._timer = createTimer(this, PRELOADER_INTERVAL_MS);
     // Signal that we swapped docShells.
     return true;
   },
   observe: function () {
     this._timer = null;
     // Start pre-loading the customization page.
     this._createBrowser();
   },
   destroy: function () {
     this._removeBrowser();
     this._timer = clearTimer(this._timer);
   },
   _createBrowser: function () {
     HostFrame.get().then(aFrame => {
       let doc = aFrame.document;
       this._browser = doc.createElementNS(XUL_NS, "browser");
       this._browser.setAttribute("type", "content");
       this._browser.setAttribute("src", CUSTOMIZATION_URL);
       this._browser.style.width = "400px";
       this._browser.style.height = "400px";
       doc.getElementById("win").appendChild(this._browser);
     });
   },
   _removeBrowser: function () {
     if (this._browser) {
       this._browser.remove();
       this._browser = null;
     }
   }
 };
 let HostFrame = {
   _frame: null,
   _deferred: null,
   get hiddenDOMDocument() {
     return Services.appShell.hiddenDOMWindow.document;
   },
   get isReady() {
     return this.hiddenDOMDocument.readyState === "complete";
   },
   get: function () {
     if (!this._deferred) {
       this._deferred = Promise.defer();
       this._create();
     }
     return this._deferred.promise;
   },
   destroy: function () {
     if (this._frame) {
       if (!Cu.isDeadWrapper(this._frame)) {
         this._frame.removeEventListener("load", this, true);
         this._frame.remove();
       }
       this._frame = null;
       this._deferred = null;
     }
   },
   handleEvent: function () {
     let contentWindow = this._frame.contentWindow;
     if (contentWindow.location.href === XUL_PAGE) {
       this._frame.removeEventListener("load", this, true);
       this._deferred.resolve(contentWindow);
     } else {
       contentWindow.location = XUL_PAGE;
     }
   },
   _create: function () {
     if (this.isReady) {
       let doc = this.hiddenDOMDocument;
       this._frame = doc.createElementNS(HTML_NS, "iframe");
       this._frame.addEventListener("load", this, true);
       doc.documentElement.appendChild(this._frame);
     } else {
       let flags = Ci.nsIThread.DISPATCH_NORMAL;
       Services.tm.currentThread.dispatch(() => this._create(), flags);
     }
   }
 };

The Tor Browser / annotate

browser/modules/CustomizationTabPreloader.jsm@b8a032363ba2 (annotated)

browser/modules/CustomizationTabPreloader.jsm