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authorThomas Groman <tgroman@nuegia.net>2020-04-20 20:49:37 -0700
committerThomas Groman <tgroman@nuegia.net>2020-04-20 20:49:37 -0700
commitf9cab004186edb425a9b88ad649726605080a17c (patch)
treee2dae51d3144e83d097a12e7a1499e3ea93f90be /webbrowser/modules/WindowsPreviewPerTab.jsm
parentf428692de8b59ab89a66502c079e1823dfda8aeb (diff)
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+/* vim: se cin sw=2 ts=2 et filetype=javascript :
+ * 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/. */
+/*
+ * This module implements the front end behavior for AeroPeek. The taskbar
+ * allows an application to expose its tabbed interface by showing thumbnail
+ * previews rather than the default window preview.
+ * Additionally, when a user hovers over a thumbnail (tab or window),
+ * they are shown a live preview of the window (or tab + its containing window).
+ *
+ * In Windows 7, a title, icon, close button and optional toolbar are shown for
+ * each preview. This feature does not make use of the toolbar. For window
+ * previews, the title is the window title and the icon the window icon. For
+ * tab previews, the title is the page title and the page's favicon. In both
+ * cases, the close button "does the right thing."
+ *
+ * The primary objects behind this feature are nsITaskbarTabPreview and
+ * nsITaskbarPreviewController. Each preview has a controller. The controller
+ * responds to the user's interactions on the taskbar and provides the required
+ * data to the preview for determining the size of the tab and thumbnail. The
+ * PreviewController class implements this interface. The preview will request
+ * the controller to provide a thumbnail or preview when the user interacts with
+ * the taskbar. To reduce the overhead of drawing the tab area, the controller
+ * implementation caches the tab's contents in a <canvas> element. If no
+ * previews or thumbnails have been requested for some time, the controller will
+ * discard its cached tab contents.
+ *
+ * Screen real estate is limited so when there are too many thumbnails to fit
+ * on the screen, the taskbar stops displaying thumbnails and instead displays
+ * just the title, icon and close button in a similar fashion to previous
+ * versions of the taskbar. If there are still too many previews to fit on the
+ * screen, the taskbar resorts to a scroll up and scroll down button pair to let
+ * the user scroll through the list of tabs. Since this is undoubtedly
+ * inconvenient for users with many tabs, the AeroPeek objects turns off all of
+ * the tab previews. This tells the taskbar to revert to one preview per window.
+ * If the number of tabs falls below this magic threshold, the preview-per-tab
+ * behavior returns. There is no reliable way to determine when the scroll
+ * buttons appear on the taskbar, so a magic pref-controlled number determines
+ * when this threshold has been crossed.
+ */
+this.EXPORTED_SYMBOLS = ["AeroPeek"];
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+
+Cu.import("resource://gre/modules/NetUtil.jsm");
+Cu.import("resource://gre/modules/PlacesUtils.jsm");
+Cu.import("resource://gre/modules/PrivateBrowsingUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+// Pref to enable/disable preview-per-tab
+const TOGGLE_PREF_NAME = "browser.taskbar.previews.enable";
+// Pref to determine the magic auto-disable threshold
+const DISABLE_THRESHOLD_PREF_NAME = "browser.taskbar.previews.max";
+// Pref to control the time in seconds that tab contents live in the cache
+const CACHE_EXPIRATION_TIME_PREF_NAME = "browser.taskbar.previews.cachetime";
+
+const WINTASKBAR_CONTRACTID = "@mozilla.org/windows-taskbar;1";
+
+// Various utility properties
+XPCOMUtils.defineLazyServiceGetter(this, "imgTools",
+ "@mozilla.org/image/tools;1",
+ "imgITools");
+XPCOMUtils.defineLazyModuleGetter(this, "PageThumbs",
+ "resource://gre/modules/PageThumbs.jsm");
+
+// nsIURI -> imgIContainer
+function _imageFromURI(uri, privateMode, callback) {
+ let channel = NetUtil.newChannel({
+ uri: uri,
+ loadUsingSystemPrincipal: true,
+ contentPolicyType: Ci.nsIContentPolicy.TYPE_INTERNAL_IMAGE
+ });
+
+ try {
+ channel.QueryInterface(Ci.nsIPrivateBrowsingChannel);
+ channel.setPrivate(privateMode);
+ } catch (e) {
+ // Ignore channels which do not support nsIPrivateBrowsingChannel
+ }
+ NetUtil.asyncFetch(channel, function(inputStream, resultCode) {
+ if (!Components.isSuccessCode(resultCode))
+ return;
+ try {
+ let out_img = { value: null };
+ imgTools.decodeImageData(inputStream, channel.contentType, out_img);
+ callback(out_img.value);
+ } catch (e) {
+ // We failed, so use the default favicon (only if this wasn't the default
+ // favicon).
+ let defaultURI = PlacesUtils.favicons.defaultFavicon;
+ if (!defaultURI.equals(uri))
+ _imageFromURI(defaultURI, privateMode, callback);
+ }
+ });
+}
+
+// string? -> imgIContainer
+function getFaviconAsImage(iconurl, privateMode, callback) {
+ if (iconurl) {
+ _imageFromURI(NetUtil.newURI(iconurl), privateMode, callback);
+ } else {
+ _imageFromURI(PlacesUtils.favicons.defaultFavicon, privateMode, callback);
+ }
+}
+
+// Snaps the given rectangle to be pixel-aligned at the given scale
+function snapRectAtScale(r, scale) {
+ let x = Math.floor(r.x * scale);
+ let y = Math.floor(r.y * scale);
+ let width = Math.ceil((r.x + r.width) * scale) - x;
+ let height = Math.ceil((r.y + r.height) * scale) - y;
+
+ r.x = x / scale;
+ r.y = y / scale;
+ r.width = width / scale;
+ r.height = height / scale;
+}
+
+// PreviewController
+
+/*
+ * This class manages the behavior of thumbnails and previews. It has the following
+ * responsibilities:
+ * 1) Responding to requests from Windows taskbar for a thumbnail or window
+ * preview.
+ * 2) Listening for DOM events that result in a thumbnail or window preview needing
+ * to be refreshed, and communicating this to the taskbar.
+ * 3) Handling queryies and returning new thumbnail or window preview images to the
+ * taskbar through PageThumbs.
+ *
+ * @param win
+ * The TabWindow (see below) that owns the preview that this controls
+ * @param tab
+ * The <tab> that this preview is associated with
+ */
+function PreviewController(win, tab) {
+ this.win = win;
+ this.tab = tab;
+ this.linkedBrowser = tab.linkedBrowser;
+ this.preview = this.win.createTabPreview(this);
+
+ this.tab.addEventListener("TabAttrModified", this, false);
+
+ XPCOMUtils.defineLazyGetter(this, "canvasPreview", function () {
+ let canvas = PageThumbs.createCanvas();
+ canvas.mozOpaque = true;
+ return canvas;
+ });
+}
+
+PreviewController.prototype = {
+ QueryInterface: XPCOMUtils.generateQI([Ci.nsITaskbarPreviewController,
+ Ci.nsIDOMEventListener]),
+
+ destroy: function () {
+ this.tab.removeEventListener("TabAttrModified", this, false);
+
+ // Break cycles, otherwise we end up leaking the window with everything
+ // attached to it.
+ delete this.win;
+ delete this.preview;
+ },
+
+ get wrappedJSObject() {
+ return this;
+ },
+
+ // Resizes the canvasPreview to 0x0, essentially freeing its memory.
+ resetCanvasPreview: function () {
+ this.canvasPreview.width = 0;
+ this.canvasPreview.height = 0;
+ },
+
+ /**
+ * Set the canvas dimensions.
+ */
+ resizeCanvasPreview: function (aRequestedWidth, aRequestedHeight) {
+ this.canvasPreview.width = aRequestedWidth;
+ this.canvasPreview.height = aRequestedHeight;
+ },
+
+
+ get zoom() {
+ // Note that winutils.fullZoom accounts for "quantization" of the zoom factor
+ // from nsIContentViewer due to conversion through appUnits.
+ // We do -not- want screenPixelsPerCSSPixel here, because that would -also-
+ // incorporate any scaling that is applied due to hi-dpi resolution options.
+ return this.tab.linkedBrowser.fullZoom;
+ },
+
+ get screenPixelsPerCSSPixel() {
+ let chromeWin = this.tab.ownerGlobal;
+ let windowUtils = chromeWin.getInterface(Ci.nsIDOMWindowUtils);
+ return windowUtils.screenPixelsPerCSSPixel;
+ },
+
+ get browserDims() {
+ return this.tab.linkedBrowser.getBoundingClientRect();
+ },
+
+ cacheBrowserDims: function () {
+ let dims = this.browserDims;
+ this._cachedWidth = dims.width;
+ this._cachedHeight = dims.height;
+ },
+
+ testCacheBrowserDims: function () {
+ let dims = this.browserDims;
+ return this._cachedWidth == dims.width &&
+ this._cachedHeight == dims.height;
+ },
+
+ /**
+ * Capture a new thumbnail image for this preview. Called by the controller
+ * in response to a request for a new thumbnail image.
+ */
+ updateCanvasPreview: function (aFullScale, aCallback) {
+ // Update our cached browser dims so that delayed resize
+ // events don't trigger another invalidation if this tab becomes active.
+ this.cacheBrowserDims();
+ PageThumbs.captureToCanvas(this.linkedBrowser, this.canvasPreview,
+ aCallback, { fullScale: aFullScale });
+ // If we're updating the canvas, then we're in the middle of a peek so
+ // don't discard the cache of previews.
+ AeroPeek.resetCacheTimer();
+ },
+
+ updateTitleAndTooltip: function () {
+ let title = this.win.tabbrowser.getWindowTitleForBrowser(this.linkedBrowser);
+ this.preview.title = title;
+ this.preview.tooltip = title;
+ },
+
+ // nsITaskbarPreviewController
+
+ // window width and height, not browser
+ get width() {
+ return this.win.width;
+ },
+
+ // window width and height, not browser
+ get height() {
+ return this.win.height;
+ },
+
+ get thumbnailAspectRatio() {
+ let browserDims = this.browserDims;
+ // Avoid returning 0
+ let tabWidth = browserDims.width || 1;
+ // Avoid divide by 0
+ let tabHeight = browserDims.height || 1;
+ return tabWidth / tabHeight;
+ },
+
+ /**
+ * Responds to taskbar requests for window previews. Returns the results asynchronously
+ * through updateCanvasPreview.
+ *
+ * @param aTaskbarCallback nsITaskbarPreviewCallback results callback
+ */
+ requestPreview: function (aTaskbarCallback) {
+ // Grab a high res content preview
+ this.resetCanvasPreview();
+ this.updateCanvasPreview(true, (aPreviewCanvas) => {
+ let winWidth = this.win.width;
+ let winHeight = this.win.height;
+
+ let composite = PageThumbs.createCanvas();
+
+ // Use transparency, Aero glass is drawn black without it.
+ composite.mozOpaque = false;
+
+ let ctx = composite.getContext('2d');
+ let scale = this.screenPixelsPerCSSPixel / this.zoom;
+
+ composite.width = winWidth * scale;
+ composite.height = winHeight * scale;
+
+ ctx.save();
+ ctx.scale(scale, scale);
+
+ // Draw chrome. Note we currently do not get scrollbars for remote frames
+ // in the image above.
+ ctx.drawWindow(this.win.win, 0, 0, winWidth, winHeight, "rgba(0,0,0,0)");
+
+ // Draw the content are into the composite canvas at the right location.
+ ctx.drawImage(aPreviewCanvas, this.browserDims.x, this.browserDims.y,
+ aPreviewCanvas.width, aPreviewCanvas.height);
+ ctx.restore();
+
+ // Deliver the resulting composite canvas to Windows
+ this.win.tabbrowser.previewTab(this.tab, function () {
+ aTaskbarCallback.done(composite, false);
+ });
+ });
+ },
+
+ /**
+ * Responds to taskbar requests for tab thumbnails. Returns the results asynchronously
+ * through updateCanvasPreview.
+ *
+ * Note Windows requests a specific width and height here, if the resulting thumbnail
+ * does not match these dimensions thumbnail display will fail.
+ *
+ * @param aTaskbarCallback nsITaskbarPreviewCallback results callback
+ * @param aRequestedWidth width of the requested thumbnail
+ * @param aRequestedHeight height of the requested thumbnail
+ */
+ requestThumbnail: function (aTaskbarCallback, aRequestedWidth, aRequestedHeight) {
+ this.resizeCanvasPreview(aRequestedWidth, aRequestedHeight);
+ this.updateCanvasPreview(false, (aThumbnailCanvas) => {
+ aTaskbarCallback.done(aThumbnailCanvas, false);
+ });
+ },
+
+ // Event handling
+
+ onClose: function () {
+ this.win.tabbrowser.removeTab(this.tab);
+ },
+
+ onActivate: function () {
+ this.win.tabbrowser.selectedTab = this.tab;
+
+ // Accept activation - this will restore the browser window
+ // if it's minimized
+ return true;
+ },
+
+ // nsIDOMEventListener
+ handleEvent: function (evt) {
+ switch (evt.type) {
+ case "TabAttrModified":
+ this.updateTitleAndTooltip();
+ break;
+ }
+ }
+};
+
+XPCOMUtils.defineLazyGetter(PreviewController.prototype, "canvasPreviewFlags",
+ function () { let canvasInterface = Ci.nsIDOMCanvasRenderingContext2D;
+ return canvasInterface.DRAWWINDOW_DRAW_VIEW
+ | canvasInterface.DRAWWINDOW_DRAW_CARET
+ | canvasInterface.DRAWWINDOW_ASYNC_DECODE_IMAGES
+ | canvasInterface.DRAWWINDOW_DO_NOT_FLUSH;
+});
+
+// TabWindow
+
+/*
+ * This class monitors a browser window for changes to its tabs
+ *
+ * @param win
+ * The nsIDOMWindow browser window
+ */
+function TabWindow(win) {
+ this.win = win;
+ this.tabbrowser = win.gBrowser;
+
+ this.previews = new Map();
+
+ for (let i = 0; i < this.tabEvents.length; i++)
+ this.tabbrowser.tabContainer.addEventListener(this.tabEvents[i], this, false);
+
+ for (let i = 0; i < this.winEvents.length; i++)
+ this.win.addEventListener(this.winEvents[i], this, false);
+
+ this.tabbrowser.addTabsProgressListener(this);
+
+ AeroPeek.windows.push(this);
+ let tabs = this.tabbrowser.tabs;
+ for (let i = 0; i < tabs.length; i++)
+ this.newTab(tabs[i]);
+
+ this.updateTabOrdering();
+ AeroPeek.checkPreviewCount();
+}
+
+TabWindow.prototype = {
+ _enabled: false,
+ _cachedWidth: 0,
+ _cachedHeight: 0,
+ tabEvents: ["TabOpen", "TabClose", "TabSelect", "TabMove"],
+ winEvents: ["resize"],
+
+ destroy: function () {
+ this._destroying = true;
+
+ let tabs = this.tabbrowser.tabs;
+
+ this.tabbrowser.removeTabsProgressListener(this);
+
+ for (let i = 0; i < this.winEvents.length; i++)
+ this.win.removeEventListener(this.winEvents[i], this, false);
+
+ for (let i = 0; i < this.tabEvents.length; i++)
+ this.tabbrowser.tabContainer.removeEventListener(this.tabEvents[i], this, false);
+
+ for (let i = 0; i < tabs.length; i++)
+ this.removeTab(tabs[i]);
+
+ let idx = AeroPeek.windows.indexOf(this.win.gTaskbarTabGroup);
+ AeroPeek.windows.splice(idx, 1);
+ AeroPeek.checkPreviewCount();
+ },
+
+ get width () {
+ return this.win.innerWidth;
+ },
+ get height () {
+ return this.win.innerHeight;
+ },
+
+ cacheDims: function () {
+ this._cachedWidth = this.width;
+ this._cachedHeight = this.height;
+ },
+
+ testCacheDims: function () {
+ return this._cachedWidth == this.width && this._cachedHeight == this.height;
+ },
+
+ // Invoked when the given tab is added to this window
+ newTab: function (tab) {
+ let controller = new PreviewController(this, tab);
+ // It's OK to add the preview now while the favicon still loads.
+ this.previews.set(tab, controller.preview);
+ AeroPeek.addPreview(controller.preview);
+ // updateTitleAndTooltip relies on having controller.preview which is lazily resolved.
+ // Now that we've updated this.previews, it will resolve successfully.
+ controller.updateTitleAndTooltip();
+ },
+
+ createTabPreview: function (controller) {
+ let docShell = this.win
+ .QueryInterface(Ci.nsIInterfaceRequestor)
+ .getInterface(Ci.nsIWebNavigation)
+ .QueryInterface(Ci.nsIDocShell);
+ let preview = AeroPeek.taskbar.createTaskbarTabPreview(docShell, controller);
+ preview.visible = AeroPeek.enabled;
+ preview.active = this.tabbrowser.selectedTab == controller.tab;
+ this.onLinkIconAvailable(controller.tab.linkedBrowser,
+ controller.tab.getAttribute("image"));
+ return preview;
+ },
+
+ // Invoked when the given tab is closed
+ removeTab: function (tab) {
+ let preview = this.previewFromTab(tab);
+ preview.active = false;
+ preview.visible = false;
+ preview.move(null);
+ preview.controller.wrappedJSObject.destroy();
+
+ this.previews.delete(tab);
+ AeroPeek.removePreview(preview);
+ },
+
+ get enabled () {
+ return this._enabled;
+ },
+
+ set enabled (enable) {
+ this._enabled = enable;
+ // Because making a tab visible requires that the tab it is next to be
+ // visible, it is far simpler to unset the 'next' tab and recreate them all
+ // at once.
+ for (let [, preview] of this.previews) {
+ preview.move(null);
+ preview.visible = enable;
+ }
+ this.updateTabOrdering();
+ },
+
+ previewFromTab: function (tab) {
+ return this.previews.get(tab);
+ },
+
+ updateTabOrdering: function () {
+ let previews = this.previews;
+ let tabs = this.tabbrowser.tabs;
+
+ // Previews are internally stored using a map, so we need to iterate the
+ // tabbrowser's array of tabs to retrieve previews in the same order.
+ let inorder = [];
+ for (let t of tabs) {
+ if (previews.has(t)) {
+ inorder.push(previews.get(t));
+ }
+ }
+
+ // Since the internal taskbar array has not yet been updated we must force
+ // on it the sorting order of our local array. To do so we must walk
+ // the local array backwards, otherwise we would send move requests in the
+ // wrong order. See bug 522610 for details.
+ for (let i = inorder.length - 1; i >= 0; i--) {
+ inorder[i].move(inorder[i + 1] || null);
+ }
+ },
+
+ // nsIDOMEventListener
+ handleEvent: function (evt) {
+ let tab = evt.originalTarget;
+ switch (evt.type) {
+ case "TabOpen":
+ this.newTab(tab);
+ this.updateTabOrdering();
+ break;
+ case "TabClose":
+ this.removeTab(tab);
+ this.updateTabOrdering();
+ break;
+ case "TabSelect":
+ this.previewFromTab(tab).active = true;
+ break;
+ case "TabMove":
+ this.updateTabOrdering();
+ break;
+ case "resize":
+ if (!AeroPeek._prefenabled)
+ return;
+ this.onResize();
+ break;
+ }
+ },
+
+ // Set or reset a timer that will invalidate visible thumbnails soon.
+ setInvalidationTimer: function () {
+ if (!this.invalidateTimer) {
+ this.invalidateTimer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+ }
+ this.invalidateTimer.cancel();
+
+ // delay 1 second before invalidating
+ this.invalidateTimer.initWithCallback(() => {
+ // invalidate every preview. note the internal implementation of
+ // invalidate ignores thumbnails that aren't visible.
+ this.previews.forEach(function (aPreview) {
+ let controller = aPreview.controller.wrappedJSObject;
+ if (!controller.testCacheBrowserDims()) {
+ controller.cacheBrowserDims();
+ aPreview.invalidate();
+ }
+ });
+ }, 1000, Ci.nsITimer.TYPE_ONE_SHOT);
+ },
+
+ onResize: function () {
+ // Specific to a window.
+
+ // Call invalidate on each tab thumbnail so that Windows will request an
+ // updated image. However don't do this repeatedly across multiple resize
+ // events triggered during window border drags.
+
+ if (this.testCacheDims()) {
+ return;
+ }
+
+ // update the window dims on our TabWindow object.
+ this.cacheDims();
+
+ // invalidate soon
+ this.setInvalidationTimer();
+ },
+
+ invalidateTabPreview: function(aBrowser) {
+ for (let [tab, preview] of this.previews) {
+ if (aBrowser == tab.linkedBrowser) {
+ preview.invalidate();
+ break;
+ }
+ }
+ },
+
+ // Browser progress listener
+
+ onLocationChange: function (aBrowser) {
+ // I'm not sure we need this, onStateChange does a really good job
+ // of picking up page changes.
+ // this.invalidateTabPreview(aBrowser);
+ },
+
+ onStateChange: function (aBrowser, aWebProgress, aRequest, aStateFlags, aStatus) {
+ if (aStateFlags & Ci.nsIWebProgressListener.STATE_STOP &&
+ aStateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK) {
+ this.invalidateTabPreview(aBrowser);
+ }
+ },
+
+ directRequestProtocols: new Set([
+ "file", "chrome", "resource", "about"
+ ]),
+ onLinkIconAvailable: function (aBrowser, aIconURL) {
+ let self = this;
+ let requestURL = null;
+ if (aIconURL) {
+ let shouldRequestFaviconURL = true;
+ try {
+ let urlObject = NetUtil.newURI(aIconURL);
+ shouldRequestFaviconURL =
+ !this.directRequestProtocols.has(urlObject.scheme);
+ } catch (ex) {}
+
+ requestURL = shouldRequestFaviconURL ?
+ "moz-anno:favicon:" + aIconURL :
+ aIconURL;
+ }
+ let isDefaultFavicon = !requestURL;
+ getFaviconAsImage(
+ requestURL,
+ PrivateBrowsingUtils.isWindowPrivate(self.win),
+ img => {
+ let index = self.tabbrowser.browsers.indexOf(aBrowser);
+ // Only add it if we've found the index and the URI is still the same.
+ // The tab could have closed, and there's no guarantee the icons
+ // will have finished fetching 'in order'.
+ if (index != -1) {
+ let tab = self.tabbrowser.tabs[index];
+ let preview = self.previews.get(tab);
+ if (tab.getAttribute("image") == aIconURL ||
+ (!preview.icon && isDefaultFavicon)) {
+ preview.icon = img;
+ }
+ }
+ }
+ );
+ }
+}
+
+// AeroPeek
+
+/*
+ * This object acts as global storage and external interface for this feature.
+ * It maintains the values of the prefs.
+ */
+this.AeroPeek = {
+ available: false,
+ // Does the pref say we're enabled?
+ __prefenabled: false,
+
+ _enabled: true,
+
+ initialized: false,
+
+ // nsITaskbarTabPreview array
+ previews: [],
+
+ // TabWindow array
+ windows: [],
+
+ // nsIWinTaskbar service
+ taskbar: null,
+
+ // Maximum number of previews
+ maxpreviews: 20,
+
+ // Length of time in seconds that previews are cached
+ cacheLifespan: 20,
+
+ initialize: function () {
+ if (!(WINTASKBAR_CONTRACTID in Cc))
+ return;
+ this.taskbar = Cc[WINTASKBAR_CONTRACTID].getService(Ci.nsIWinTaskbar);
+ this.available = this.taskbar.available;
+ if (!this.available)
+ return;
+
+ this.prefs.addObserver(TOGGLE_PREF_NAME, this, true);
+ this.enabled = this._prefenabled = this.prefs.getBoolPref(TOGGLE_PREF_NAME);
+ this.initialized = true;
+ },
+
+ destroy: function destroy() {
+ this._enabled = false;
+
+ if (this.cacheTimer)
+ this.cacheTimer.cancel();
+ },
+
+ get enabled() {
+ return this._enabled;
+ },
+
+ set enabled(enable) {
+ if (this._enabled == enable)
+ return;
+
+ this._enabled = enable;
+
+ this.windows.forEach(function (win) {
+ win.enabled = enable;
+ });
+ },
+
+ get _prefenabled() {
+ return this.__prefenabled;
+ },
+
+ set _prefenabled(enable) {
+ if (enable == this.__prefenabled) {
+ return;
+ }
+ this.__prefenabled = enable;
+
+ if (enable) {
+ this.enable();
+ } else {
+ this.disable();
+ }
+ },
+
+ _observersAdded: false,
+
+ enable() {
+ if (!this._observersAdded) {
+ this.prefs.addObserver(DISABLE_THRESHOLD_PREF_NAME, this, true);
+ this.prefs.addObserver(CACHE_EXPIRATION_TIME_PREF_NAME, this, true);
+ PlacesUtils.history.addObserver(this, true);
+ this._observersAdded = true;
+ }
+
+ this.cacheLifespan = this.prefs.getIntPref(CACHE_EXPIRATION_TIME_PREF_NAME);
+
+ this.maxpreviews = this.prefs.getIntPref(DISABLE_THRESHOLD_PREF_NAME);
+
+ // If the user toggled us on/off while the browser was already up
+ // (rather than this code running on startup because the pref was
+ // already set to true), we must initialize previews for open windows:
+ if (this.initialized) {
+ let browserWindows = Services.wm.getEnumerator("navigator:browser");
+ while (browserWindows.hasMoreElements()) {
+ let win = browserWindows.getNext();
+ if (!win.closed) {
+ this.onOpenWindow(win);
+ }
+ }
+ }
+ },
+
+ disable() {
+ while (this.windows.length) {
+ // We can't call onCloseWindow here because it'll bail if we're not
+ // enabled.
+ let tabWinObject = this.windows[0];
+ tabWinObject.destroy(); // This will remove us from the array.
+ delete tabWinObject.win.gTaskbarTabGroup; // Tidy up the window.
+ }
+ },
+
+ addPreview: function (preview) {
+ this.previews.push(preview);
+ this.checkPreviewCount();
+ },
+
+ removePreview: function (preview) {
+ let idx = this.previews.indexOf(preview);
+ this.previews.splice(idx, 1);
+ this.checkPreviewCount();
+ },
+
+ checkPreviewCount: function () {
+ if (!this._prefenabled) {
+ return;
+ }
+ this.enabled = this.previews.length <= this.maxpreviews;
+ },
+
+ onOpenWindow: function (win) {
+ // This occurs when the taskbar service is not available (xp, vista)
+ if (!this.available || !this._prefenabled)
+ return;
+
+ win.gTaskbarTabGroup = new TabWindow(win);
+ },
+
+ onCloseWindow: function (win) {
+ // This occurs when the taskbar service is not available (xp, vista)
+ if (!this.available || !this._prefenabled)
+ return;
+
+ win.gTaskbarTabGroup.destroy();
+ delete win.gTaskbarTabGroup;
+
+ if (this.windows.length == 0)
+ this.destroy();
+ },
+
+ resetCacheTimer: function () {
+ this.cacheTimer.cancel();
+ this.cacheTimer.init(this, 1000*this.cacheLifespan, Ci.nsITimer.TYPE_ONE_SHOT);
+ },
+
+ // nsIObserver
+ observe: function (aSubject, aTopic, aData) {
+ if (aTopic == "nsPref:changed" && aData == TOGGLE_PREF_NAME) {
+ this._prefenabled = this.prefs.getBoolPref(TOGGLE_PREF_NAME);
+ }
+ if (!this._prefenabled) {
+ return;
+ }
+ switch (aTopic) {
+ case "nsPref:changed":
+ if (aData == CACHE_EXPIRATION_TIME_PREF_NAME)
+ break;
+
+ if (aData == DISABLE_THRESHOLD_PREF_NAME)
+ this.maxpreviews = this.prefs.getIntPref(DISABLE_THRESHOLD_PREF_NAME);
+ // Might need to enable/disable ourselves
+ this.checkPreviewCount();
+ break;
+ case "timer-callback":
+ this.previews.forEach(function (preview) {
+ let controller = preview.controller.wrappedJSObject;
+ controller.resetCanvasPreview();
+ });
+ break;
+ }
+ },
+
+ /* nsINavHistoryObserver implementation */
+ onBeginUpdateBatch() {},
+ onEndUpdateBatch() {},
+ onVisit() {},
+ onTitleChanged() {},
+ onFrecencyChanged() {},
+ onManyFrecenciesChanged() {},
+ onDeleteURI() {},
+ onClearHistory() {},
+ onDeleteVisits() {},
+ onPageChanged(uri, changedConst, newValue) {
+ if (this.enabled && changedConst == Ci.nsINavHistoryObserver.ATTRIBUTE_FAVICON) {
+ for (let win of this.windows) {
+ for (let [tab, ] of win.previews) {
+ if (tab.getAttribute("image") == newValue) {
+ win.onLinkIconAvailable(tab.linkedBrowser, newValue);
+ }
+ }
+ }
+ }
+ },
+
+ QueryInterface: XPCOMUtils.generateQI([
+ Ci.nsISupportsWeakReference,
+ Ci.nsINavHistoryObserver,
+ Ci.nsIObserver
+ ]),
+};
+
+XPCOMUtils.defineLazyGetter(AeroPeek, "cacheTimer", () =>
+ Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer)
+);
+
+XPCOMUtils.defineLazyServiceGetter(AeroPeek, "prefs",
+ "@mozilla.org/preferences-service;1",
+ "nsIPrefBranch");
+
+AeroPeek.initialize();