1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/browser/modules/BrowserNewTabPreloader.jsm Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,445 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.6 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +"use strict";
1.9 +
1.10 +this.EXPORTED_SYMBOLS = ["BrowserNewTabPreloader"];
1.11 +
1.12 +const Cu = Components.utils;
1.13 +const Cc = Components.classes;
1.14 +const Ci = Components.interfaces;
1.15 +
1.16 +Cu.import("resource://gre/modules/Services.jsm");
1.17 +Cu.import("resource://gre/modules/XPCOMUtils.jsm");
1.18 +Cu.import("resource://gre/modules/Promise.jsm");
1.19 +
1.20 +const HTML_NS = "http://www.w3.org/1999/xhtml";
1.21 +const XUL_NS = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
1.22 +const XUL_PAGE = "data:application/vnd.mozilla.xul+xml;charset=utf-8,<window%20id='win'/>";
1.23 +const NEWTAB_URL = "about:newtab";
1.24 +const PREF_BRANCH = "browser.newtab.";
1.25 +
1.26 +// The interval between swapping in a preload docShell and kicking off the
1.27 +// next preload in the background.
1.28 +const PRELOADER_INTERVAL_MS = 600;
1.29 +// The initial delay before we start preloading our first new tab page. The
1.30 +// timer is started after the first 'browser-delayed-startup' has been sent.
1.31 +const PRELOADER_INIT_DELAY_MS = 5000;
1.32 +// The number of miliseconds we'll wait after we received a notification that
1.33 +// causes us to update our list of browsers and tabbrowser sizes. This acts as
1.34 +// kind of a damper when too many events are occuring in quick succession.
1.35 +const PRELOADER_UPDATE_DELAY_MS = 3000;
1.36 +
1.37 +const TOPIC_TIMER_CALLBACK = "timer-callback";
1.38 +const TOPIC_DELAYED_STARTUP = "browser-delayed-startup-finished";
1.39 +const TOPIC_XUL_WINDOW_CLOSED = "xul-window-destroyed";
1.40 +
1.41 +const FRAME_SCRIPT_URL = "chrome://browser/content/newtab/preloaderContent.js";
1.42 +
1.43 +function createTimer(obj, delay) {
1.44 + let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
1.45 + timer.init(obj, delay, Ci.nsITimer.TYPE_ONE_SHOT);
1.46 + return timer;
1.47 +}
1.48 +
1.49 +function clearTimer(timer) {
1.50 + if (timer) {
1.51 + timer.cancel();
1.52 + }
1.53 + return null;
1.54 +}
1.55 +
1.56 +this.BrowserNewTabPreloader = {
1.57 + init: function Preloader_init() {
1.58 + Initializer.start();
1.59 + },
1.60 +
1.61 + uninit: function Preloader_uninit() {
1.62 + Initializer.stop();
1.63 + HostFrame.destroy();
1.64 + Preferences.uninit();
1.65 + HiddenBrowsers.uninit();
1.66 + },
1.67 +
1.68 + newTab: function Preloader_newTab(aTab) {
1.69 + let swapped = false;
1.70 + let win = aTab.ownerDocument.defaultView;
1.71 + if (win.gBrowser) {
1.72 + let utils = win.QueryInterface(Ci.nsIInterfaceRequestor)
1.73 + .getInterface(Ci.nsIDOMWindowUtils);
1.74 +
1.75 + let {width, height} = utils.getBoundsWithoutFlushing(win.gBrowser);
1.76 + let hiddenBrowser = HiddenBrowsers.get(width, height)
1.77 + if (hiddenBrowser) {
1.78 + swapped = hiddenBrowser.swapWithNewTab(aTab);
1.79 + }
1.80 +
1.81 + // aTab's browser is now visible and is therefore allowed to make
1.82 + // background captures.
1.83 + let msgMan = aTab.linkedBrowser.messageManager;
1.84 + msgMan.loadFrameScript(FRAME_SCRIPT_URL, false);
1.85 + msgMan.sendAsyncMessage("BrowserNewTabPreloader:allowBackgroundCaptures");
1.86 + }
1.87 +
1.88 + return swapped;
1.89 + }
1.90 +};
1.91 +
1.92 +Object.freeze(BrowserNewTabPreloader);
1.93 +
1.94 +let Initializer = {
1.95 + _timer: null,
1.96 + _observing: false,
1.97 +
1.98 + start: function Initializer_start() {
1.99 + Services.obs.addObserver(this, TOPIC_DELAYED_STARTUP, false);
1.100 + this._observing = true;
1.101 + },
1.102 +
1.103 + stop: function Initializer_stop() {
1.104 + this._timer = clearTimer(this._timer);
1.105 +
1.106 + if (this._observing) {
1.107 + Services.obs.removeObserver(this, TOPIC_DELAYED_STARTUP);
1.108 + this._observing = false;
1.109 + }
1.110 + },
1.111 +
1.112 + observe: function Initializer_observe(aSubject, aTopic, aData) {
1.113 + if (aTopic == TOPIC_DELAYED_STARTUP) {
1.114 + Services.obs.removeObserver(this, TOPIC_DELAYED_STARTUP);
1.115 + this._observing = false;
1.116 + this._startTimer();
1.117 + } else if (aTopic == TOPIC_TIMER_CALLBACK) {
1.118 + this._timer = null;
1.119 + this._startPreloader();
1.120 + }
1.121 + },
1.122 +
1.123 + _startTimer: function Initializer_startTimer() {
1.124 + this._timer = createTimer(this, PRELOADER_INIT_DELAY_MS);
1.125 + },
1.126 +
1.127 + _startPreloader: function Initializer_startPreloader() {
1.128 + Preferences.init();
1.129 + if (Preferences.enabled) {
1.130 + HiddenBrowsers.init();
1.131 + }
1.132 + }
1.133 +};
1.134 +
1.135 +let Preferences = {
1.136 + _enabled: null,
1.137 + _branch: null,
1.138 +
1.139 + get enabled() {
1.140 + if (this._enabled === null) {
1.141 + this._enabled = this._branch.getBoolPref("preload") &&
1.142 + !this._branch.prefHasUserValue("url");
1.143 + }
1.144 +
1.145 + return this._enabled;
1.146 + },
1.147 +
1.148 + init: function Preferences_init() {
1.149 + this._branch = Services.prefs.getBranch(PREF_BRANCH);
1.150 + this._branch.addObserver("", this, false);
1.151 + },
1.152 +
1.153 + uninit: function Preferences_uninit() {
1.154 + if (this._branch) {
1.155 + this._branch.removeObserver("", this);
1.156 + this._branch = null;
1.157 + }
1.158 + },
1.159 +
1.160 + observe: function Preferences_observe() {
1.161 + let prevEnabled = this._enabled;
1.162 + this._enabled = null;
1.163 +
1.164 + if (prevEnabled && !this.enabled) {
1.165 + HiddenBrowsers.uninit();
1.166 + } else if (!prevEnabled && this.enabled) {
1.167 + HiddenBrowsers.init();
1.168 + }
1.169 + },
1.170 +};
1.171 +
1.172 +let HiddenBrowsers = {
1.173 + _browsers: null,
1.174 + _updateTimer: null,
1.175 +
1.176 + _topics: [
1.177 + TOPIC_DELAYED_STARTUP,
1.178 + TOPIC_XUL_WINDOW_CLOSED
1.179 + ],
1.180 +
1.181 + init: function () {
1.182 + this._browsers = new Map();
1.183 + this._updateBrowserSizes();
1.184 + this._topics.forEach(t => Services.obs.addObserver(this, t, false));
1.185 + },
1.186 +
1.187 + uninit: function () {
1.188 + if (this._browsers) {
1.189 + this._topics.forEach(t => Services.obs.removeObserver(this, t, false));
1.190 + this._updateTimer = clearTimer(this._updateTimer);
1.191 +
1.192 + for (let [key, browser] of this._browsers) {
1.193 + browser.destroy();
1.194 + }
1.195 + this._browsers = null;
1.196 + }
1.197 + },
1.198 +
1.199 + get: function (width, height) {
1.200 + // We haven't been initialized, yet.
1.201 + if (!this._browsers) {
1.202 + return null;
1.203 + }
1.204 +
1.205 + let key = width + "x" + height;
1.206 + if (!this._browsers.has(key)) {
1.207 + // Update all browsers' sizes if we can't find a matching one.
1.208 + this._updateBrowserSizes();
1.209 + }
1.210 +
1.211 + // We should now have a matching browser.
1.212 + if (this._browsers.has(key)) {
1.213 + return this._browsers.get(key);
1.214 + }
1.215 +
1.216 + // We should never be here. Return the first browser we find.
1.217 + Cu.reportError("NewTabPreloader: no matching browser found after updating");
1.218 + for (let [size, browser] of this._browsers) {
1.219 + return browser;
1.220 + }
1.221 +
1.222 + // We should really never be here.
1.223 + Cu.reportError("NewTabPreloader: not even a single browser was found?");
1.224 + return null;
1.225 + },
1.226 +
1.227 + observe: function (subject, topic, data) {
1.228 + if (topic === TOPIC_TIMER_CALLBACK) {
1.229 + this._updateTimer = null;
1.230 + this._updateBrowserSizes();
1.231 + } else {
1.232 + this._updateTimer = clearTimer(this._updateTimer);
1.233 + this._updateTimer = createTimer(this, PRELOADER_UPDATE_DELAY_MS);
1.234 + }
1.235 + },
1.236 +
1.237 + _updateBrowserSizes: function () {
1.238 + let sizes = this._collectTabBrowserSizes();
1.239 + let toRemove = [];
1.240 +
1.241 + // Iterate all browsers and check that they
1.242 + // each can be assigned to one of the sizes.
1.243 + for (let [key, browser] of this._browsers) {
1.244 + if (sizes.has(key)) {
1.245 + // We already have a browser for that size, great!
1.246 + sizes.delete(key);
1.247 + } else {
1.248 + // This browser is superfluous or needs to be resized.
1.249 + toRemove.push(browser);
1.250 + this._browsers.delete(key);
1.251 + }
1.252 + }
1.253 +
1.254 + // Iterate all sizes that we couldn't find a browser for.
1.255 + for (let [key, {width, height}] of sizes) {
1.256 + let browser;
1.257 + if (toRemove.length) {
1.258 + // Let's just resize one of the superfluous
1.259 + // browsers and put it back into the map.
1.260 + browser = toRemove.shift();
1.261 + browser.resize(width, height);
1.262 + } else {
1.263 + // No more browsers to reuse, create a new one.
1.264 + browser = new HiddenBrowser(width, height);
1.265 + }
1.266 +
1.267 + this._browsers.set(key, browser);
1.268 + }
1.269 +
1.270 + // Finally, remove all browsers we don't need anymore.
1.271 + toRemove.forEach(b => b.destroy());
1.272 + },
1.273 +
1.274 + _collectTabBrowserSizes: function () {
1.275 + let sizes = new Map();
1.276 +
1.277 + function tabBrowserBounds() {
1.278 + let wins = Services.ww.getWindowEnumerator("navigator:browser");
1.279 + while (wins.hasMoreElements()) {
1.280 + let win = wins.getNext();
1.281 + if (win.gBrowser) {
1.282 + let utils = win.QueryInterface(Ci.nsIInterfaceRequestor)
1.283 + .getInterface(Ci.nsIDOMWindowUtils);
1.284 + yield utils.getBoundsWithoutFlushing(win.gBrowser);
1.285 + }
1.286 + }
1.287 + }
1.288 +
1.289 + // Collect the sizes of all <tabbrowser>s out there.
1.290 + for (let {width, height} of tabBrowserBounds()) {
1.291 + if (width > 0 && height > 0) {
1.292 + let key = width + "x" + height;
1.293 + if (!sizes.has(key)) {
1.294 + sizes.set(key, {width: width, height: height});
1.295 + }
1.296 + }
1.297 + }
1.298 +
1.299 + return sizes;
1.300 + }
1.301 +};
1.302 +
1.303 +function HiddenBrowser(width, height) {
1.304 + this.resize(width, height);
1.305 + this._createBrowser();
1.306 +}
1.307 +
1.308 +HiddenBrowser.prototype = {
1.309 + _width: null,
1.310 + _height: null,
1.311 + _timer: null,
1.312 +
1.313 + get isPreloaded() {
1.314 + return this._browser &&
1.315 + this._browser.contentDocument &&
1.316 + this._browser.contentDocument.readyState === "complete" &&
1.317 + this._browser.currentURI.spec === NEWTAB_URL;
1.318 + },
1.319 +
1.320 + swapWithNewTab: function (aTab) {
1.321 + if (!this.isPreloaded || this._timer) {
1.322 + return false;
1.323 + }
1.324 +
1.325 + let win = aTab.ownerDocument.defaultView;
1.326 + let tabbrowser = win.gBrowser;
1.327 +
1.328 + if (!tabbrowser) {
1.329 + return false;
1.330 + }
1.331 +
1.332 + // Swap docShells.
1.333 + tabbrowser.swapNewTabWithBrowser(aTab, this._browser);
1.334 +
1.335 + // Load all default frame scripts attached to the target window.
1.336 + let mm = aTab.linkedBrowser.messageManager;
1.337 + let scripts = win.messageManager.getDelayedFrameScripts();
1.338 + Array.forEach(scripts, ([script, runGlobal]) => mm.loadFrameScript(script, true, runGlobal));
1.339 +
1.340 + // Remove the browser, it will be recreated by a timer.
1.341 + this._removeBrowser();
1.342 +
1.343 + // Start a timer that will kick off preloading the next newtab page.
1.344 + this._timer = createTimer(this, PRELOADER_INTERVAL_MS);
1.345 +
1.346 + // Signal that we swapped docShells.
1.347 + return true;
1.348 + },
1.349 +
1.350 + observe: function () {
1.351 + this._timer = null;
1.352 +
1.353 + // Start pre-loading the new tab page.
1.354 + this._createBrowser();
1.355 + },
1.356 +
1.357 + resize: function (width, height) {
1.358 + this._width = width;
1.359 + this._height = height;
1.360 + this._applySize();
1.361 + },
1.362 +
1.363 + destroy: function () {
1.364 + this._removeBrowser();
1.365 + this._timer = clearTimer(this._timer);
1.366 + },
1.367 +
1.368 + _applySize: function () {
1.369 + if (this._browser) {
1.370 + this._browser.style.width = this._width + "px";
1.371 + this._browser.style.height = this._height + "px";
1.372 + }
1.373 + },
1.374 +
1.375 + _createBrowser: function () {
1.376 + HostFrame.get().then(aFrame => {
1.377 + let doc = aFrame.document;
1.378 + this._browser = doc.createElementNS(XUL_NS, "browser");
1.379 + this._browser.setAttribute("type", "content");
1.380 + this._browser.setAttribute("src", NEWTAB_URL);
1.381 + this._applySize();
1.382 + doc.getElementById("win").appendChild(this._browser);
1.383 + });
1.384 + },
1.385 +
1.386 + _removeBrowser: function () {
1.387 + if (this._browser) {
1.388 + this._browser.remove();
1.389 + this._browser = null;
1.390 + }
1.391 + }
1.392 +};
1.393 +
1.394 +let HostFrame = {
1.395 + _frame: null,
1.396 + _deferred: null,
1.397 +
1.398 + get hiddenDOMDocument() {
1.399 + return Services.appShell.hiddenDOMWindow.document;
1.400 + },
1.401 +
1.402 + get isReady() {
1.403 + return this.hiddenDOMDocument.readyState === "complete";
1.404 + },
1.405 +
1.406 + get: function () {
1.407 + if (!this._deferred) {
1.408 + this._deferred = Promise.defer();
1.409 + this._create();
1.410 + }
1.411 +
1.412 + return this._deferred.promise;
1.413 + },
1.414 +
1.415 + destroy: function () {
1.416 + if (this._frame) {
1.417 + if (!Cu.isDeadWrapper(this._frame)) {
1.418 + this._frame.removeEventListener("load", this, true);
1.419 + this._frame.remove();
1.420 + }
1.421 +
1.422 + this._frame = null;
1.423 + this._deferred = null;
1.424 + }
1.425 + },
1.426 +
1.427 + handleEvent: function () {
1.428 + let contentWindow = this._frame.contentWindow;
1.429 + if (contentWindow.location.href === XUL_PAGE) {
1.430 + this._frame.removeEventListener("load", this, true);
1.431 + this._deferred.resolve(contentWindow);
1.432 + } else {
1.433 + contentWindow.location = XUL_PAGE;
1.434 + }
1.435 + },
1.436 +
1.437 + _create: function () {
1.438 + if (this.isReady) {
1.439 + let doc = this.hiddenDOMDocument;
1.440 + this._frame = doc.createElementNS(HTML_NS, "iframe");
1.441 + this._frame.addEventListener("load", this, true);
1.442 + doc.documentElement.appendChild(this._frame);
1.443 + } else {
1.444 + let flags = Ci.nsIThread.DISPATCH_NORMAL;
1.445 + Services.tm.currentThread.dispatch(() => this._create(), flags);
1.446 + }
1.447 + }
1.448 +};
