The Tor Browser: comparison browser/modules/CustomizationTabPreloader.jsm

--1:000000000000
+:ab572520a9ec
+/* 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 / file comparison

comparison: browser/modules/CustomizationTabPreloader.jsm

browser/modules/CustomizationTabPreloader.jsm