michael@0: /* vim: se cin sw=2 ts=2 et filetype=javascript :
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: /*
michael@0:  * This module implements the front end behavior for AeroPeek. Starting in
michael@0:  * Windows Vista, the taskbar began showing live thumbnail previews of windows
michael@0:  * when the user hovered over the window icon in the taskbar. Starting with
michael@0:  * Windows 7, the taskbar allows an application to expose its tabbed interface
michael@0:  * in the taskbar by showing thumbnail previews rather than the default window
michael@0:  * preview. Additionally, when a user hovers over a thumbnail (tab or window),
michael@0:  * they are shown a live preview of the window (or tab + its containing window).
michael@0:  *
michael@0:  * In Windows 7, a title, icon, close button and optional toolbar are shown for
michael@0:  * each preview. This feature does not make use of the toolbar. For window
michael@0:  * previews, the title is the window title and the icon the window icon. For
michael@0:  * tab previews, the title is the page title and the page's favicon. In both
michael@0:  * cases, the close button "does the right thing."
michael@0:  *
michael@0:  * The primary objects behind this feature are nsITaskbarTabPreview and
michael@0:  * nsITaskbarPreviewController. Each preview has a controller. The controller
michael@0:  * responds to the user's interactions on the taskbar and provides the required
michael@0:  * data to the preview for determining the size of the tab and thumbnail. The
michael@0:  * PreviewController class implements this interface. The preview will request
michael@0:  * the controller to provide a thumbnail or preview when the user interacts with
michael@0:  * the taskbar. To reduce the overhead of drawing the tab area, the controller
michael@0:  * implementation caches the tab's contents in a <canvas> element. If no
michael@0:  * previews or thumbnails have been requested for some time, the controller will
michael@0:  * discard its cached tab contents.
michael@0:  *
michael@0:  * Screen real estate is limited so when there are too many thumbnails to fit
michael@0:  * on the screen, the taskbar stops displaying thumbnails and instead displays
michael@0:  * just the title, icon and close button in a similar fashion to previous
michael@0:  * versions of the taskbar. If there are still too many previews to fit on the 
michael@0:  * screen, the taskbar resorts to a scroll up and scroll down button pair to let
michael@0:  * the user scroll through the list of tabs. Since this is undoubtedly
michael@0:  * inconvenient for users with many tabs, the AeroPeek objects turns off all of
michael@0:  * the tab previews. This tells the taskbar to revert to one preview per window.
michael@0:  * If the number of tabs falls below this magic threshold, the preview-per-tab
michael@0:  * behavior returns. There is no reliable way to determine when the scroll
michael@0:  * buttons appear on the taskbar, so a magic pref-controlled number determines
michael@0:  * when this threshold has been crossed.
michael@0:  */
michael@0: this.EXPORTED_SYMBOLS = ["AeroPeek"];
michael@0: 
michael@0: const Cc = Components.classes;
michael@0: const Ci = Components.interfaces;
michael@0: const Cu = Components.utils;
michael@0: 
michael@0: Cu.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: Cu.import("resource://gre/modules/NetUtil.jsm");
michael@0: Cu.import("resource://gre/modules/PrivateBrowsingUtils.jsm");
michael@0: 
michael@0: // Pref to enable/disable preview-per-tab
michael@0: const TOGGLE_PREF_NAME = "browser.taskbar.previews.enable";
michael@0: // Pref to determine the magic auto-disable threshold
michael@0: const DISABLE_THRESHOLD_PREF_NAME = "browser.taskbar.previews.max";
michael@0: // Pref to control the time in seconds that tab contents live in the cache
michael@0: const CACHE_EXPIRATION_TIME_PREF_NAME = "browser.taskbar.previews.cachetime";
michael@0: 
michael@0: const WINTASKBAR_CONTRACTID = "@mozilla.org/windows-taskbar;1";
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //// Various utility properties
michael@0: XPCOMUtils.defineLazyServiceGetter(this, "ioSvc",
michael@0:                                    "@mozilla.org/network/io-service;1",
michael@0:                                    "nsIIOService");
michael@0: XPCOMUtils.defineLazyServiceGetter(this, "imgTools",
michael@0:                                    "@mozilla.org/image/tools;1",
michael@0:                                    "imgITools");
michael@0: XPCOMUtils.defineLazyServiceGetter(this, "faviconSvc",
michael@0:                                    "@mozilla.org/browser/favicon-service;1",
michael@0:                                    "nsIFaviconService");
michael@0: 
michael@0: // nsIURI -> imgIContainer
michael@0: function _imageFromURI(uri, privateMode, callback) {
michael@0:   let channel = ioSvc.newChannelFromURI(uri);
michael@0:   try {
michael@0:     channel.QueryInterface(Ci.nsIPrivateBrowsingChannel);
michael@0:     channel.setPrivate(privateMode);
michael@0:   } catch (e) {
michael@0:     // Ignore channels which do not support nsIPrivateBrowsingChannel
michael@0:   }
michael@0:   NetUtil.asyncFetch(channel, function(inputStream, resultCode) {
michael@0:     if (!Components.isSuccessCode(resultCode))
michael@0:       return;
michael@0:     try {
michael@0:       let out_img = { value: null };
michael@0:       imgTools.decodeImageData(inputStream, channel.contentType, out_img);
michael@0:       callback(out_img.value);
michael@0:     } catch (e) {
michael@0:       // We failed, so use the default favicon (only if this wasn't the default
michael@0:       // favicon).
michael@0:       let defaultURI = faviconSvc.defaultFavicon;
michael@0:       if (!defaultURI.equals(uri))
michael@0:         _imageFromURI(defaultURI, callback);
michael@0:     }
michael@0:   });
michael@0: }
michael@0: 
michael@0: // string? -> imgIContainer
michael@0: function getFaviconAsImage(iconurl, privateMode, callback) {
michael@0:   if (iconurl)
michael@0:     _imageFromURI(NetUtil.newURI(iconurl), privateMode, callback);
michael@0:   else
michael@0:     _imageFromURI(faviconSvc.defaultFavicon, privateMode, callback);
michael@0: }
michael@0: 
michael@0: // Snaps the given rectangle to be pixel-aligned at the given scale
michael@0: function snapRectAtScale(r, scale) {
michael@0:   let x = Math.floor(r.x * scale);
michael@0:   let y = Math.floor(r.y * scale);
michael@0:   let width = Math.ceil((r.x + r.width) * scale) - x;
michael@0:   let height = Math.ceil((r.y + r.height) * scale) - y;
michael@0: 
michael@0:   r.x = x / scale;
michael@0:   r.y = y / scale;
michael@0:   r.width = width / scale;
michael@0:   r.height = height / scale;
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //// PreviewController
michael@0: 
michael@0: /*
michael@0:  * This class manages the behavior of the preview.
michael@0:  *
michael@0:  * To give greater performance when drawing, the dirty areas of the content
michael@0:  * window are tracked and drawn on demand into a canvas of the same size.
michael@0:  * This provides a great increase in responsiveness when drawing a preview
michael@0:  * for unchanged (or even only slightly changed) tabs.
michael@0:  *
michael@0:  * @param win
michael@0:  *        The TabWindow (see below) that owns the preview that this controls
michael@0:  * @param tab
michael@0:  *        The <tab> that this preview is associated with
michael@0:  */
michael@0: function PreviewController(win, tab) {
michael@0:   this.win = win;
michael@0:   this.tab = tab;
michael@0:   this.linkedBrowser = tab.linkedBrowser;
michael@0:   this.preview = this.win.createTabPreview(this);
michael@0: 
michael@0:   this.linkedBrowser.addEventListener("MozAfterPaint", this, false);
michael@0:   this.tab.addEventListener("TabAttrModified", this, false);
michael@0: 
michael@0:   XPCOMUtils.defineLazyGetter(this, "canvasPreview", function () {
michael@0:     let canvas = this.win.win.document.createElementNS("http://www.w3.org/1999/xhtml", "canvas");
michael@0:     canvas.mozOpaque = true;
michael@0:     return canvas;
michael@0:   });
michael@0: 
michael@0:   XPCOMUtils.defineLazyGetter(this, "dirtyRegion",
michael@0:     function () {
michael@0:       let dirtyRegion = Cc["@mozilla.org/gfx/region;1"]
michael@0:                        .createInstance(Ci.nsIScriptableRegion);
michael@0:       dirtyRegion.init();
michael@0:       return dirtyRegion;
michael@0:     });
michael@0: 
michael@0:   XPCOMUtils.defineLazyGetter(this, "winutils",
michael@0:     function () {
michael@0:       let win = tab.linkedBrowser.contentWindow;
michael@0:       return win.QueryInterface(Ci.nsIInterfaceRequestor)
michael@0:                 .getInterface(Ci.nsIDOMWindowUtils);
michael@0:   });
michael@0: }
michael@0: 
michael@0: PreviewController.prototype = {
michael@0:   QueryInterface: XPCOMUtils.generateQI([Ci.nsITaskbarPreviewController,
michael@0:                                          Ci.nsIDOMEventListener]),
michael@0:   destroy: function () {
michael@0:     this.tab.removeEventListener("TabAttrModified", this, false);
michael@0:     this.linkedBrowser.removeEventListener("MozAfterPaint", this, false);
michael@0: 
michael@0:     // Break cycles, otherwise we end up leaking the window with everything
michael@0:     // attached to it.
michael@0:     delete this.win;
michael@0:     delete this.preview;
michael@0:     delete this.dirtyRegion;
michael@0:   },
michael@0:   get wrappedJSObject() {
michael@0:     return this;
michael@0:   },
michael@0: 
michael@0:   get dirtyRects() {
michael@0:     let rectstream = this.dirtyRegion.getRects();
michael@0:     if (!rectstream)
michael@0:       return [];
michael@0:     let rects = [];
michael@0:     for (let i = 0; i < rectstream.length; i+= 4) {
michael@0:       let r = {x:      rectstream[i],
michael@0:                y:      rectstream[i+1],
michael@0:                width:  rectstream[i+2],
michael@0:                height: rectstream[i+3]};
michael@0:       rects.push(r);
michael@0:     }
michael@0:     return rects;
michael@0:   },
michael@0: 
michael@0:   // Resizes the canvasPreview to 0x0, essentially freeing its memory.
michael@0:   // updateCanvasPreview() will detect the size mismatch as a resize event
michael@0:   // the next time it is called.
michael@0:   resetCanvasPreview: function () {
michael@0:     this.canvasPreview.width = 0;
michael@0:     this.canvasPreview.height = 0;
michael@0:   },
michael@0: 
michael@0:   get zoom() {
michael@0:     // Note that winutils.fullZoom accounts for "quantization" of the zoom factor
michael@0:     // from nsIMarkupDocumentViewer due to conversion through appUnits.
michael@0:     // We do -not- want screenPixelsPerCSSPixel here, because that would -also-
michael@0:     // incorporate any scaling that is applied due to hi-dpi resolution options.
michael@0:     return this.winutils.fullZoom;
michael@0:   },
michael@0: 
michael@0:   // Updates the controller's canvas with the parts of the <browser> that need
michael@0:   // to be redrawn.
michael@0:   updateCanvasPreview: function () {
michael@0:     let win = this.linkedBrowser.contentWindow;
michael@0:     let bx = this.linkedBrowser.boxObject;
michael@0:     // Check for resize
michael@0:     if (bx.width != this.canvasPreview.width ||
michael@0:         bx.height != this.canvasPreview.height) {
michael@0:       // Invalidate the entire area and repaint
michael@0:       this.onTabPaint({left:0, top:0, right:win.innerWidth, bottom:win.innerHeight});
michael@0:       this.canvasPreview.width = bx.width;
michael@0:       this.canvasPreview.height = bx.height;
michael@0:     }
michael@0: 
michael@0:     // Draw dirty regions
michael@0:     let ctx = this.canvasPreview.getContext("2d");
michael@0:     let scale = this.zoom;
michael@0: 
michael@0:     let flags = this.canvasPreviewFlags;
michael@0:     // The dirty region may include parts that are offscreen so we clip to the
michael@0:     // canvas area.
michael@0:     this.dirtyRegion.intersectRect(0, 0, win.innerWidth, win.innerHeight);
michael@0:     this.dirtyRects.forEach(function (r) {
michael@0:       // We need to snap the rectangle to be pixel aligned in the destination
michael@0:       // coordinate space. Otherwise natively themed widgets might not draw.
michael@0:       snapRectAtScale(r, scale);
michael@0:       let x = r.x;
michael@0:       let y = r.y;
michael@0:       let width = r.width;
michael@0:       let height = r.height;
michael@0: 
michael@0:       ctx.save();
michael@0:       ctx.scale(scale, scale);
michael@0:       ctx.translate(x, y);
michael@0:       ctx.drawWindow(win, x, y, width, height, "white", flags);
michael@0:       ctx.restore();
michael@0:     });
michael@0:     this.dirtyRegion.setToRect(0,0,0,0);
michael@0: 
michael@0:     // If we're updating the canvas, then we're in the middle of a peek so
michael@0:     // don't discard the cache of previews.
michael@0:     AeroPeek.resetCacheTimer();
michael@0:   },
michael@0: 
michael@0:   onTabPaint: function (rect) {
michael@0:     let x = Math.floor(rect.left),
michael@0:         y = Math.floor(rect.top),
michael@0:         width = Math.ceil(rect.right) - x,
michael@0:         height = Math.ceil(rect.bottom) - y;
michael@0:     this.dirtyRegion.unionRect(x, y, width, height);
michael@0:   },
michael@0: 
michael@0:   updateTitleAndTooltip: function () {
michael@0:     let title = this.win.tabbrowser.getWindowTitleForBrowser(this.linkedBrowser);
michael@0:     this.preview.title = title;
michael@0:     this.preview.tooltip = title;
michael@0:   },
michael@0: 
michael@0:   //////////////////////////////////////////////////////////////////////////////
michael@0:   //// nsITaskbarPreviewController 
michael@0: 
michael@0:   get width() {
michael@0:     return this.win.width;
michael@0:   },
michael@0: 
michael@0:   get height() {
michael@0:     return this.win.height;
michael@0:   },
michael@0: 
michael@0:   get thumbnailAspectRatio() {
michael@0:     let boxObject = this.tab.linkedBrowser.boxObject;
michael@0:     // Avoid returning 0
michael@0:     let tabWidth = boxObject.width || 1;
michael@0:     // Avoid divide by 0
michael@0:     let tabHeight = boxObject.height || 1;
michael@0:     return tabWidth / tabHeight;
michael@0:   },
michael@0: 
michael@0:   drawPreview: function (ctx) {
michael@0:     let self = this;
michael@0:     this.win.tabbrowser.previewTab(this.tab, function () self.previewTabCallback(ctx));
michael@0: 
michael@0:     // We must avoid having the frame drawn around the window. See bug 520807
michael@0:     return false;
michael@0:   },
michael@0: 
michael@0:   previewTabCallback: function (ctx) {
michael@0:     // This will extract the resolution-scale component of the scaling we need,
michael@0:     // which should be applied to both chrome and content;
michael@0:     // the page zoom component is applied (to content only) within updateCanvasPreview.
michael@0:     let scale = this.winutils.screenPixelsPerCSSPixel / this.winutils.fullZoom;
michael@0:     ctx.save();
michael@0:     ctx.scale(scale, scale);
michael@0:     let width = this.win.width;
michael@0:     let height = this.win.height;
michael@0:     // Draw our toplevel window
michael@0:     ctx.drawWindow(this.win.win, 0, 0, width, height, "transparent");
michael@0: 
michael@0:     // XXX (jfkthame): Pending tabs don't seem to draw with the proper scaling
michael@0:     // unless we use this block of code; but doing this for "normal" (loaded) tabs
michael@0:     // results in blurry rendering on hidpi systems, so we avoid it if possible.
michael@0:     // I don't understand why pending and loaded tabs behave differently here...
michael@0:     // (see bug 857061).
michael@0:     if (this.tab.hasAttribute("pending")) {
michael@0:       // Compositor, where art thou?
michael@0:       // Draw the tab content on top of the toplevel window
michael@0:       this.updateCanvasPreview();
michael@0: 
michael@0:       let boxObject = this.linkedBrowser.boxObject;
michael@0:       ctx.translate(boxObject.x, boxObject.y);
michael@0:       ctx.drawImage(this.canvasPreview, 0, 0);
michael@0:     }
michael@0: 
michael@0:     ctx.restore();
michael@0:   },
michael@0: 
michael@0:   drawThumbnail: function (ctx, width, height) {
michael@0:     this.updateCanvasPreview();
michael@0: 
michael@0:     let scale = width/this.linkedBrowser.boxObject.width;
michael@0:     ctx.scale(scale, scale);
michael@0:     ctx.drawImage(this.canvasPreview, 0, 0);
michael@0: 
michael@0:     // Don't draw a frame around the thumbnail
michael@0:     return false;
michael@0:   },
michael@0: 
michael@0:   onClose: function () {
michael@0:     this.win.tabbrowser.removeTab(this.tab);
michael@0:   },
michael@0: 
michael@0:   onActivate: function () {
michael@0:     this.win.tabbrowser.selectedTab = this.tab;
michael@0: 
michael@0:     // Accept activation - this will restore the browser window
michael@0:     // if it's minimized
michael@0:     return true;
michael@0:   },
michael@0: 
michael@0:   //// nsIDOMEventListener
michael@0:   handleEvent: function (evt) {
michael@0:     switch (evt.type) {
michael@0:       case "MozAfterPaint":
michael@0:         if (evt.originalTarget === this.linkedBrowser.contentWindow) {
michael@0:           let clientRects = evt.clientRects;
michael@0:           let length = clientRects.length;
michael@0:           for (let i = 0; i < length; i++) {
michael@0:             let r = clientRects.item(i);
michael@0:             this.onTabPaint(r);
michael@0:           }
michael@0:         }
michael@0:         let preview = this.preview;
michael@0:         if (preview.visible)
michael@0:           preview.invalidate();
michael@0:         break;
michael@0:       case "TabAttrModified":
michael@0:         this.updateTitleAndTooltip();
michael@0:         break;
michael@0:     }
michael@0:   }
michael@0: };
michael@0: 
michael@0: XPCOMUtils.defineLazyGetter(PreviewController.prototype, "canvasPreviewFlags",
michael@0:   function () { let canvasInterface = Ci.nsIDOMCanvasRenderingContext2D;
michael@0:                 return canvasInterface.DRAWWINDOW_DRAW_VIEW
michael@0:                      | canvasInterface.DRAWWINDOW_DRAW_CARET
michael@0:                      | canvasInterface.DRAWWINDOW_ASYNC_DECODE_IMAGES
michael@0:                      | canvasInterface.DRAWWINDOW_DO_NOT_FLUSH;
michael@0: });
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //// TabWindow
michael@0: 
michael@0: /*
michael@0:  * This class monitors a browser window for changes to its tabs
michael@0:  *
michael@0:  * @param win
michael@0:  *        The nsIDOMWindow browser window 
michael@0:  */
michael@0: function TabWindow(win) {
michael@0:   this.win = win;
michael@0:   this.tabbrowser = win.gBrowser;
michael@0: 
michael@0:   this.previews = new Map();
michael@0: 
michael@0:   for (let i = 0; i < this.tabEvents.length; i++)
michael@0:     this.tabbrowser.tabContainer.addEventListener(this.tabEvents[i], this, false);
michael@0:   this.tabbrowser.addTabsProgressListener(this);
michael@0: 
michael@0:   for (let i = 0; i < this.winEvents.length; i++)
michael@0:     this.win.addEventListener(this.winEvents[i], this, false);
michael@0: 
michael@0:   AeroPeek.windows.push(this);
michael@0:   let tabs = this.tabbrowser.tabs;
michael@0:   for (let i = 0; i < tabs.length; i++)
michael@0:     this.newTab(tabs[i]);
michael@0: 
michael@0:   this.updateTabOrdering();
michael@0:   AeroPeek.checkPreviewCount();
michael@0: }
michael@0: 
michael@0: TabWindow.prototype = {
michael@0:   _enabled: false,
michael@0:   tabEvents: ["TabOpen", "TabClose", "TabSelect", "TabMove"],
michael@0:   winEvents: ["tabviewshown", "tabviewhidden"],
michael@0: 
michael@0:   destroy: function () {
michael@0:     this._destroying = true;
michael@0: 
michael@0:     let tabs = this.tabbrowser.tabs;
michael@0: 
michael@0:     this.tabbrowser.removeTabsProgressListener(this);
michael@0:     for (let i = 0; i < this.tabEvents.length; i++)
michael@0:       this.tabbrowser.tabContainer.removeEventListener(this.tabEvents[i], this, false);
michael@0: 
michael@0:     for (let i = 0; i < this.winEvents.length; i++)
michael@0:       this.win.removeEventListener(this.winEvents[i], this, false);
michael@0: 
michael@0:     for (let i = 0; i < tabs.length; i++)
michael@0:       this.removeTab(tabs[i]);
michael@0: 
michael@0:     let idx = AeroPeek.windows.indexOf(this.win.gTaskbarTabGroup);
michael@0:     AeroPeek.windows.splice(idx, 1);
michael@0:     AeroPeek.checkPreviewCount();
michael@0:   },
michael@0: 
michael@0:   get width () {
michael@0:     return this.win.innerWidth;
michael@0:   },
michael@0:   get height () {
michael@0:     return this.win.innerHeight;
michael@0:   },
michael@0: 
michael@0:   // Invoked when the given tab is added to this window
michael@0:   newTab: function (tab) {
michael@0:     let controller = new PreviewController(this, tab);
michael@0:     // It's OK to add the preview now while the favicon still loads.
michael@0:     this.previews.set(tab, controller.preview);
michael@0:     AeroPeek.addPreview(controller.preview);
michael@0:     // updateTitleAndTooltip relies on having controller.preview which is lazily resolved.
michael@0:     // Now that we've updated this.previews, it will resolve successfully.
michael@0:     controller.updateTitleAndTooltip();
michael@0:   },
michael@0: 
michael@0:   createTabPreview: function (controller) {
michael@0:     let docShell = this.win
michael@0:                   .QueryInterface(Ci.nsIInterfaceRequestor)
michael@0:                   .getInterface(Ci.nsIWebNavigation)
michael@0:                   .QueryInterface(Ci.nsIDocShell);
michael@0:     let preview = AeroPeek.taskbar.createTaskbarTabPreview(docShell, controller);
michael@0:     preview.visible = AeroPeek.enabled;
michael@0:     preview.active = this.tabbrowser.selectedTab == controller.tab;
michael@0:     // Grab the default favicon
michael@0:     getFaviconAsImage(null, PrivateBrowsingUtils.isWindowPrivate(this.win), function (img) {
michael@0:       // It is possible that we've already gotten the real favicon, so make sure
michael@0:       // we have not set one before setting this default one.
michael@0:       if (!preview.icon)
michael@0:         preview.icon = img;
michael@0:     });
michael@0: 
michael@0:     return preview;
michael@0:   },
michael@0: 
michael@0:   // Invoked when the given tab is closed
michael@0:   removeTab: function (tab) {
michael@0:     let preview = this.previewFromTab(tab);
michael@0:     preview.active = false;
michael@0:     preview.visible = false;
michael@0:     preview.move(null);
michael@0:     preview.controller.wrappedJSObject.destroy();
michael@0: 
michael@0:     this.previews.delete(tab);
michael@0:     AeroPeek.removePreview(preview);
michael@0:   },
michael@0: 
michael@0:   get enabled () {
michael@0:     return this._enabled;
michael@0:   },
michael@0: 
michael@0:   set enabled (enable) {
michael@0:     this._enabled = enable;
michael@0:     // Because making a tab visible requires that the tab it is next to be
michael@0:     // visible, it is far simpler to unset the 'next' tab and recreate them all
michael@0:     // at once.
michael@0:     for (let [tab, preview] of this.previews) {
michael@0:       preview.move(null);
michael@0:       preview.visible = enable;
michael@0:     }
michael@0:     this.updateTabOrdering();
michael@0:   },
michael@0: 
michael@0:   previewFromTab: function (tab) {
michael@0:     return this.previews.get(tab);
michael@0:   },
michael@0: 
michael@0:   updateTabOrdering: function () {
michael@0:     let previews = this.previews;
michael@0:     let tabs = this.tabbrowser.tabs;
michael@0: 
michael@0:     // Previews are internally stored using a map, so we need to iterate the
michael@0:     // tabbrowser's array of tabs to retrieve previews in the same order.
michael@0:     let inorder = [previews.get(t) for (t of tabs) if (previews.has(t))];
michael@0: 
michael@0:     // Since the internal taskbar array has not yet been updated we must force
michael@0:     // on it the sorting order of our local array.  To do so we must walk
michael@0:     // the local array backwards, otherwise we would send move requests in the
michael@0:     // wrong order.  See bug 522610 for details.
michael@0:     for (let i = inorder.length - 1; i >= 0; i--) {
michael@0:       inorder[i].move(inorder[i + 1] || null);
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   //// nsIDOMEventListener
michael@0:   handleEvent: function (evt) {
michael@0:     let tab = evt.originalTarget;
michael@0:     switch (evt.type) {
michael@0:       case "TabOpen":
michael@0:         this.newTab(tab);
michael@0:         this.updateTabOrdering();
michael@0:         break;
michael@0:       case "TabClose":
michael@0:         this.removeTab(tab);
michael@0:         this.updateTabOrdering();
michael@0:         break;
michael@0:       case "TabSelect":
michael@0:         this.previewFromTab(tab).active = true;
michael@0:         break;
michael@0:       case "TabMove":
michael@0:         this.updateTabOrdering();
michael@0:         break;
michael@0:       case "tabviewshown":
michael@0:         this.enabled = false;
michael@0:         break;
michael@0:       case "tabviewhidden":
michael@0:         if (!AeroPeek._prefenabled)
michael@0:           return;
michael@0:         this.enabled = true;
michael@0:         break;
michael@0:     }
michael@0:   },
michael@0: 
michael@0:   //// Browser progress listener
michael@0:   onLinkIconAvailable: function (aBrowser, aIconURL) {
michael@0:     let self = this;
michael@0:     getFaviconAsImage(aIconURL, PrivateBrowsingUtils.isWindowPrivate(this.win), function (img) {
michael@0:       let index = self.tabbrowser.browsers.indexOf(aBrowser);
michael@0:       // Only add it if we've found the index.  The tab could have closed!
michael@0:       if (index != -1) {
michael@0:         let tab = self.tabbrowser.tabs[index];
michael@0:         self.previews.get(tab).icon = img;
michael@0:       }
michael@0:     });
michael@0:   }
michael@0: }
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //// AeroPeek
michael@0: 
michael@0: /*
michael@0:  * This object acts as global storage and external interface for this feature.
michael@0:  * It maintains the values of the prefs.
michael@0:  */
michael@0: this.AeroPeek = {
michael@0:   available: false,
michael@0:   // Does the pref say we're enabled?
michael@0:   _prefenabled: true,
michael@0: 
michael@0:   _enabled: true,
michael@0: 
michael@0:   // nsITaskbarTabPreview array
michael@0:   previews: [],
michael@0: 
michael@0:   // TabWindow array
michael@0:   windows: [],
michael@0: 
michael@0:   // nsIWinTaskbar service
michael@0:   taskbar: null,
michael@0: 
michael@0:   // Maximum number of previews
michael@0:   maxpreviews: 20,
michael@0: 
michael@0:   // Length of time in seconds that previews are cached
michael@0:   cacheLifespan: 20,
michael@0: 
michael@0:   initialize: function () {
michael@0:     if (!(WINTASKBAR_CONTRACTID in Cc))
michael@0:       return;
michael@0:     this.taskbar = Cc[WINTASKBAR_CONTRACTID].getService(Ci.nsIWinTaskbar);
michael@0:     this.available = this.taskbar.available;
michael@0:     if (!this.available)
michael@0:       return;
michael@0: 
michael@0:     this.prefs.addObserver(TOGGLE_PREF_NAME, this, false);
michael@0:     this.prefs.addObserver(DISABLE_THRESHOLD_PREF_NAME, this, false);
michael@0:     this.prefs.addObserver(CACHE_EXPIRATION_TIME_PREF_NAME, this, false);
michael@0: 
michael@0:     this.cacheLifespan = this.prefs.getIntPref(CACHE_EXPIRATION_TIME_PREF_NAME);
michael@0: 
michael@0:     this.maxpreviews = this.prefs.getIntPref(DISABLE_THRESHOLD_PREF_NAME);
michael@0: 
michael@0:     this.enabled = this._prefenabled = this.prefs.getBoolPref(TOGGLE_PREF_NAME);
michael@0:   },
michael@0: 
michael@0:   destroy: function destroy() {
michael@0:     this._enabled = false;
michael@0: 
michael@0:     this.prefs.removeObserver(TOGGLE_PREF_NAME, this);
michael@0:     this.prefs.removeObserver(DISABLE_THRESHOLD_PREF_NAME, this);
michael@0:     this.prefs.removeObserver(CACHE_EXPIRATION_TIME_PREF_NAME, this);
michael@0: 
michael@0:     if (this.cacheTimer)
michael@0:       this.cacheTimer.cancel();
michael@0:   },
michael@0: 
michael@0:   get enabled() {
michael@0:     return this._enabled;
michael@0:   },
michael@0: 
michael@0:   set enabled(enable) {
michael@0:     if (this._enabled == enable)
michael@0:       return;
michael@0: 
michael@0:     this._enabled = enable;
michael@0: 
michael@0:     this.windows.forEach(function (win) {
michael@0:       win.enabled = enable;
michael@0:     });
michael@0:   },
michael@0: 
michael@0:   addPreview: function (preview) {
michael@0:     this.previews.push(preview);
michael@0:     this.checkPreviewCount();
michael@0:   },
michael@0: 
michael@0:   removePreview: function (preview) {
michael@0:     let idx = this.previews.indexOf(preview);
michael@0:     this.previews.splice(idx, 1);
michael@0:     this.checkPreviewCount();
michael@0:   },
michael@0: 
michael@0:   checkPreviewCount: function () {
michael@0:     if (this.previews.length > this.maxpreviews)
michael@0:       this.enabled = false;
michael@0:     else
michael@0:       this.enabled = this._prefenabled;
michael@0:   },
michael@0: 
michael@0:   onOpenWindow: function (win) {
michael@0:     // This occurs when the taskbar service is not available (xp, vista)
michael@0:     if (!this.available)
michael@0:       return;
michael@0: 
michael@0:     win.gTaskbarTabGroup = new TabWindow(win);
michael@0:   },
michael@0: 
michael@0:   onCloseWindow: function (win) {
michael@0:     // This occurs when the taskbar service is not available (xp, vista)
michael@0:     if (!this.available)
michael@0:       return;
michael@0: 
michael@0:     win.gTaskbarTabGroup.destroy();
michael@0:     delete win.gTaskbarTabGroup;
michael@0: 
michael@0:     if (this.windows.length == 0)
michael@0:       this.destroy();
michael@0:   },
michael@0: 
michael@0:   resetCacheTimer: function () {
michael@0:     this.cacheTimer.cancel();
michael@0:     this.cacheTimer.init(this, 1000*this.cacheLifespan, Ci.nsITimer.TYPE_ONE_SHOT);
michael@0:   },
michael@0: 
michael@0:   //// nsIObserver
michael@0:   observe: function (aSubject, aTopic, aData) {
michael@0:     switch (aTopic) {
michael@0:       case "nsPref:changed":
michael@0:         if (aData == CACHE_EXPIRATION_TIME_PREF_NAME)
michael@0:           break;
michael@0: 
michael@0:         if (aData == TOGGLE_PREF_NAME)
michael@0:           this._prefenabled = this.prefs.getBoolPref(TOGGLE_PREF_NAME);
michael@0:         else if (aData == DISABLE_THRESHOLD_PREF_NAME)
michael@0:           this.maxpreviews = this.prefs.getIntPref(DISABLE_THRESHOLD_PREF_NAME);
michael@0:         // Might need to enable/disable ourselves
michael@0:         this.checkPreviewCount();
michael@0:         break;
michael@0:       case "timer-callback":
michael@0:         this.previews.forEach(function (preview) {
michael@0:           let controller = preview.controller.wrappedJSObject;
michael@0:           controller.resetCanvasPreview();
michael@0:         });
michael@0:         break;
michael@0:     }
michael@0:   }
michael@0: };
michael@0: 
michael@0: XPCOMUtils.defineLazyGetter(AeroPeek, "cacheTimer", function ()
michael@0:   Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer)
michael@0: );
michael@0: 
michael@0: XPCOMUtils.defineLazyServiceGetter(AeroPeek, "prefs",
michael@0:                                    "@mozilla.org/preferences-service;1",
michael@0:                                    "nsIPrefBranch");
michael@0: 
michael@0: AeroPeek.initialize();