The Tor Browser: browser/components/downloads/content/downloads.js@7e26c7da4463 (annotated)

browser/components/downloads/content/downloads.js@7e26c7da4463 (annotated)

browser/components/downloads/content/downloads.js

Wed, 31 Dec 2014 06:55:50 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:55:50 +0100
changeset 2: 7e26c7da4463
permissions: -rw-r--r--

Added tag UPSTREAM_283F7C6 for changeset ca08bd8f51b2

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* 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/. */
 /**
  * Handles the Downloads panel user interface for each browser window.
  *
  * This file includes the following constructors and global objects:
  *
  * DownloadsPanel
  * Main entry point for the downloads panel interface.
  *
  * DownloadsOverlayLoader
  * Allows loading the downloads panel and the status indicator interfaces on
  * demand, to improve startup performance.
  *
  * DownloadsView
  * Builds and updates the downloads list widget, responding to changes in the
  * download state and real-time data.  In addition, handles part of the user
  * interaction events raised by the downloads list widget.
  *
  * DownloadsViewItem
  * Builds and updates a single item in the downloads list widget, responding to
  * changes in the download state and real-time data.
  *
  * DownloadsViewController
  * Handles part of the user interaction events raised by the downloads list
  * widget, in particular the "commands" that apply to multiple items, and
  * dispatches the commands that apply to individual items.
  *
  * DownloadsViewItemController
  * Handles all the user interaction events, in particular the "commands",
  * related to a single item in the downloads list widgets.
  */
 /**
  * A few words on focus and focusrings
  *
  * We do quite a few hacks in the Downloads Panel for focusrings. In fact, we
  * basically suppress most if not all XUL-level focusrings, and style/draw
  * them ourselves (using :focus instead of -moz-focusring). There are a few
  * reasons for this:
  *
  * 1) Richlists on OSX don't have focusrings; instead, they are shown as
  *    selected. This makes for some ambiguity when we have a focused/selected
  *    item in the list, and the mouse is hovering a completed download (which
  *    highlights).
  * 2) Windows doesn't show focusrings until after the first time that tab is
  *    pressed (and by then you're focusing the second item in the panel).
  * 3) Richlistbox sets -moz-focusring even when we select it with a mouse.
  *
  * In general, the desired behaviour is to focus the first item after pressing
  * tab/down, and show that focus with a ring. Then, if the mouse moves over
  * the panel, to hide that focus ring; essentially resetting us to the state
  * before pressing the key.
  *
  * We end up capturing the tab/down key events, and preventing their default
  * behaviour. We then set a "keyfocus" attribute on the panel, which allows
  * us to draw a ring around the currently focused element. If the panel is
  * closed or the mouse moves over the panel, we remove the attribute.
  */
 "use strict";
 ////////////////////////////////////////////////////////////////////////////////
 //// Globals
 XPCOMUtils.defineLazyModuleGetter(this, "DownloadUtils",
                                   "resource://gre/modules/DownloadUtils.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "DownloadsCommon",
                                   "resource:///modules/DownloadsCommon.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "OS",
                                   "resource://gre/modules/osfile.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "PrivateBrowsingUtils",
                                   "resource://gre/modules/PrivateBrowsingUtils.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
                                   "resource://gre/modules/PlacesUtils.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
                                   "resource://gre/modules/NetUtil.jsm");
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadsPanel
 /**
  * Main entry point for the downloads panel interface.
  */
 const DownloadsPanel = {
   //////////////////////////////////////////////////////////////////////////////
   //// Initialization and termination
   /**
    * Internal state of the downloads panel, based on one of the kState
    * constants.  This is not the same state as the XUL panel element.
    */
   _state: 0,
   /** The panel is not linked to downloads data yet. */
   get kStateUninitialized() 0,
   /** This object is linked to data, but the panel is invisible. */
   get kStateHidden() 1,
   /** The panel will be shown as soon as possible. */
   get kStateWaitingData() 2,
   /** The panel is almost shown - we're just waiting to get a handle on the
       anchor. */
   get kStateWaitingAnchor() 3,
   /** The panel is open. */
   get kStateShown() 4,
   /**
    * Location of the panel overlay.
    */
   get kDownloadsOverlay()
       "chrome://browser/content/downloads/downloadsOverlay.xul",
   /**
    * Starts loading the download data in background, without opening the panel.
    * Use showPanel instead to load the data and open the panel at the same time.
    *
    * @param aCallback
    *        Called when initialization is complete.
    */
   initialize: function DP_initialize(aCallback)
   {
     DownloadsCommon.log("Attempting to initialize DownloadsPanel for a window.");
     if (this._state != this.kStateUninitialized) {
       DownloadsCommon.log("DownloadsPanel is already initialized.");
       DownloadsOverlayLoader.ensureOverlayLoaded(this.kDownloadsOverlay,
                                                  aCallback);
       return;
     }
     this._state = this.kStateHidden;
     window.addEventListener("unload", this.onWindowUnload, false);
     // Load and resume active downloads if required.  If there are downloads to
     // be shown in the panel, they will be loaded asynchronously.
     DownloadsCommon.initializeAllDataLinks();
     // Now that data loading has eventually started, load the required XUL
     // elements and initialize our views.
     DownloadsCommon.log("Ensuring DownloadsPanel overlay loaded.");
     DownloadsOverlayLoader.ensureOverlayLoaded(this.kDownloadsOverlay,
                                                function DP_I_callback() {
       DownloadsViewController.initialize();
       DownloadsCommon.log("Attaching DownloadsView...");
       DownloadsCommon.getData(window).addView(DownloadsView);
       DownloadsCommon.getSummary(window, DownloadsView.kItemCountLimit)
                      .addView(DownloadsSummary);
       DownloadsCommon.log("DownloadsView attached - the panel for this window",
                           "should now see download items come in.");
       DownloadsPanel._attachEventListeners();
       DownloadsCommon.log("DownloadsPanel initialized.");
       aCallback();
     });
   },
   /**
    * Closes the downloads panel and frees the internal resources related to the
    * downloads.  The downloads panel can be reopened later, even after this
    * function has been called.
    */
   terminate: function DP_terminate()
   {
     DownloadsCommon.log("Attempting to terminate DownloadsPanel for a window.");
     if (this._state == this.kStateUninitialized) {
       DownloadsCommon.log("DownloadsPanel was never initialized. Nothing to do.");
       return;
     }
     window.removeEventListener("unload", this.onWindowUnload, false);
     // Ensure that the panel is closed before shutting down.
     this.hidePanel();
     DownloadsViewController.terminate();
     DownloadsCommon.getData(window).removeView(DownloadsView);
     DownloadsCommon.getSummary(window, DownloadsView.kItemCountLimit)
                    .removeView(DownloadsSummary);
     this._unattachEventListeners();
     this._state = this.kStateUninitialized;
     DownloadsSummary.active = false;
     DownloadsCommon.log("DownloadsPanel terminated.");
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Panel interface
   /**
    * Main panel element in the browser window, or null if the panel overlay
    * hasn't been loaded yet.
    */
   get panel()
   {
     // If the downloads panel overlay hasn't loaded yet, just return null
     // without reseting this.panel.
     let downloadsPanel = document.getElementById("downloadsPanel");
     if (!downloadsPanel)
       return null;
     delete this.panel;
     return this.panel = downloadsPanel;
   },
   /**
    * Starts opening the downloads panel interface, anchored to the downloads
    * button of the browser window.  The list of downloads to display is
    * initialized the first time this method is called, and the panel is shown
    * only when data is ready.
    */
   showPanel: function DP_showPanel()
   {
     DownloadsCommon.log("Opening the downloads panel.");
     if (this.isPanelShowing) {
       DownloadsCommon.log("Panel is already showing - focusing instead.");
       this._focusPanel();
       return;
     }
     this.initialize(function DP_SP_callback() {
       // Delay displaying the panel because this function will sometimes be
       // called while another window is closing (like the window for selecting
       // whether to save or open the file), and that would cause the panel to
       // close immediately.
       setTimeout(function () DownloadsPanel._openPopupIfDataReady(), 0);
     }.bind(this));
     DownloadsCommon.log("Waiting for the downloads panel to appear.");
     this._state = this.kStateWaitingData;
   },
   /**
    * Hides the downloads panel, if visible, but keeps the internal state so that
    * the panel can be reopened quickly if required.
    */
   hidePanel: function DP_hidePanel()
   {
     DownloadsCommon.log("Closing the downloads panel.");
     if (!this.isPanelShowing) {
       DownloadsCommon.log("Downloads panel is not showing - nothing to do.");
       return;
     }
     this.panel.hidePopup();
     // Ensure that we allow the panel to be reopened.  Note that, if the popup
     // was open, then the onPopupHidden event handler has already updated the
     // current state, otherwise we must update the state ourselves.
     this._state = this.kStateHidden;
     DownloadsCommon.log("Downloads panel is now closed.");
   },
   /**
    * Indicates whether the panel is shown or will be shown.
    */
   get isPanelShowing()
   {
     return this._state == this.kStateWaitingData ||
            this._state == this.kStateWaitingAnchor ||
            this._state == this.kStateShown;
   },
   /**
    * Returns whether the user has started keyboard navigation.
    */
   get keyFocusing()
   {
     return this.panel.hasAttribute("keyfocus");
   },
   /**
    * Set to true if the user has started keyboard navigation, and we should be
    * showing focusrings in the panel. Also adds a mousemove event handler to
    * the panel which disables keyFocusing.
    */
   set keyFocusing(aValue)
   {
     if (aValue) {
       this.panel.setAttribute("keyfocus", "true");
       this.panel.addEventListener("mousemove", this);
     } else {
       this.panel.removeAttribute("keyfocus");
       this.panel.removeEventListener("mousemove", this);
     }
     return aValue;
   },
   /**
    * Handles the mousemove event for the panel, which disables focusring
    * visualization.
    */
   handleEvent: function DP_handleEvent(aEvent)
   {
     if (aEvent.type == "mousemove") {
       this.keyFocusing = false;
     }
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Callback functions from DownloadsView
   /**
    * Called after data loading finished.
    */
   onViewLoadCompleted: function DP_onViewLoadCompleted()
   {
     this._openPopupIfDataReady();
   },
   //////////////////////////////////////////////////////////////////////////////
   //// User interface event functions
   onWindowUnload: function DP_onWindowUnload()
   {
     // This function is registered as an event listener, we can't use "this".
     DownloadsPanel.terminate();
   },
   onPopupShown: function DP_onPopupShown(aEvent)
   {
     // Ignore events raised by nested popups.
     if (aEvent.target != aEvent.currentTarget) {
       return;
     }
     DownloadsCommon.log("Downloads panel has shown.");
     this._state = this.kStateShown;
     // Since at most one popup is open at any given time, we can set globally.
     DownloadsCommon.getIndicatorData(window).attentionSuppressed = true;
     // Ensure that the first item is selected when the panel is focused.
     if (DownloadsView.richListBox.itemCount > 0 &&
         DownloadsView.richListBox.selectedIndex == -1) {
       DownloadsView.richListBox.selectedIndex = 0;
     }
     this._focusPanel();
   },
   onPopupHidden: function DP_onPopupHidden(aEvent)
   {
     // Ignore events raised by nested popups.
     if (aEvent.target != aEvent.currentTarget) {
       return;
     }
     DownloadsCommon.log("Downloads panel has hidden.");
     // Removes the keyfocus attribute so that we stop handling keyboard
     // navigation.
     this.keyFocusing = false;
     // Since at most one popup is open at any given time, we can set globally.
     DownloadsCommon.getIndicatorData(window).attentionSuppressed = false;
     // Allow the anchor to be hidden.
     DownloadsButton.releaseAnchor();
     // Allow the panel to be reopened.
     this._state = this.kStateHidden;
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Related operations
   /**
    * Shows or focuses the user interface dedicated to downloads history.
    */
   showDownloadsHistory: function DP_showDownloadsHistory()
   {
     DownloadsCommon.log("Showing download history.");
     // Hide the panel before showing another window, otherwise focus will return
     // to the browser window when the panel closes automatically.
     this.hidePanel();
     BrowserDownloadsUI();
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Internal functions
   /**
    * Attach event listeners to a panel element. These listeners should be
    * removed in _unattachEventListeners. This is called automatically after the
    * panel has successfully loaded.
    */
   _attachEventListeners: function DP__attachEventListeners()
   {
     // Handle keydown to support accel-V.
     this.panel.addEventListener("keydown", this._onKeyDown.bind(this), false);
     // Handle keypress to be able to preventDefault() events before they reach
     // the richlistbox, for keyboard navigation.
     this.panel.addEventListener("keypress", this._onKeyPress.bind(this), false);
   },
   /**
    * Unattach event listeners that were added in _attachEventListeners. This
    * is called automatically on panel termination.
    */
   _unattachEventListeners: function DP__unattachEventListeners()
   {
     this.panel.removeEventListener("keydown", this._onKeyDown.bind(this),
                                    false);
     this.panel.removeEventListener("keypress", this._onKeyPress.bind(this),
                                    false);
   },
   _onKeyPress: function DP__onKeyPress(aEvent)
   {
     // Handle unmodified keys only.
     if (aEvent.altKey || aEvent.ctrlKey || aEvent.shiftKey || aEvent.metaKey) {
       return;
     }
     let richListBox = DownloadsView.richListBox;
     // If the user has pressed the tab, up, or down cursor key, start keyboard
     // navigation, thus enabling focusrings in the panel.  Keyboard navigation
     // is automatically disabled if the user moves the mouse on the panel, or
     // if the panel is closed.
     if ((aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_TAB ||
         aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_UP ||
         aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_DOWN) &&
         !this.keyFocusing) {
       this.keyFocusing = true;
       // Ensure there's a selection, we will show the focus ring around it and
       // prevent the richlistbox from changing the selection.
       if (DownloadsView.richListBox.selectedIndex == -1)
         DownloadsView.richListBox.selectedIndex = 0;
       aEvent.preventDefault();
       return;
     }
     if (aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_DOWN) {
       // If the last element in the list is selected, or the footer is already
       // focused, focus the footer.
       if (richListBox.selectedItem === richListBox.lastChild ||
           document.activeElement.parentNode.id === "downloadsFooter") {
         DownloadsFooter.focus();
         aEvent.preventDefault();
         return;
       }
     }
     // Pass keypress events to the richlistbox view when it's focused.
     if (document.activeElement === richListBox) {
       DownloadsView.onDownloadKeyPress(aEvent);
     }
   },
   /**
    * Keydown listener that listens for the keys to start key focusing, as well
    * as the the accel-V "paste" event, which initiates a file download if the
    * pasted item can be resolved to a URI.
    */
   _onKeyDown: function DP__onKeyDown(aEvent)
   {
     // If the footer is focused and the downloads list has at least 1 element
     // in it, focus the last element in the list when going up.
     if (aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_UP &&
         document.activeElement.parentNode.id === "downloadsFooter" &&
         DownloadsView.richListBox.firstChild) {
       DownloadsView.richListBox.focus();
       DownloadsView.richListBox.selectedItem = DownloadsView.richListBox.lastChild;
       aEvent.preventDefault();
       return;
     }
     let pasting = aEvent.keyCode == Ci.nsIDOMKeyEvent.DOM_VK_V &&
 #ifdef XP_MACOSX
                   aEvent.metaKey;
 #else
                   aEvent.ctrlKey;
 #endif
     if (!pasting) {
       return;
     }
     DownloadsCommon.log("Received a paste event.");
     let trans = Cc["@mozilla.org/widget/transferable;1"]
                   .createInstance(Ci.nsITransferable);
     trans.init(null);
     let flavors = ["text/x-moz-url", "text/unicode"];
     flavors.forEach(trans.addDataFlavor);
     Services.clipboard.getData(trans, Services.clipboard.kGlobalClipboard);
     // Getting the data or creating the nsIURI might fail
     try {
       let data = {};
       trans.getAnyTransferData({}, data, {});
       let [url, name] = data.value
                             .QueryInterface(Ci.nsISupportsString)
                             .data
                             .split("\n");
       if (!url) {
         return;
       }
       let uri = NetUtil.newURI(url);
       DownloadsCommon.log("Pasted URL seems valid. Starting download.");
       DownloadURL(uri.spec, name, document);
     } catch (ex) {}
   },
   /**
    * Move focus to the main element in the downloads panel, unless another
    * element in the panel is already focused.
    */
   _focusPanel: function DP_focusPanel()
   {
     // We may be invoked while the panel is still waiting to be shown.
     if (this._state != this.kStateShown) {
       return;
     }
     let element = document.commandDispatcher.focusedElement;
     while (element && element != this.panel) {
       element = element.parentNode;
     }
     if (!element) {
       if (DownloadsView.richListBox.itemCount > 0) {
         DownloadsView.richListBox.focus();
       } else {
         DownloadsFooter.focus();
       }
     }
   },
   /**
    * Opens the downloads panel when data is ready to be displayed.
    */
   _openPopupIfDataReady: function DP_openPopupIfDataReady()
   {
     // We don't want to open the popup if we already displayed it, or if we are
     // still loading data.
     if (this._state != this.kStateWaitingData || DownloadsView.loading) {
       return;
     }
     this._state = this.kStateWaitingAnchor;
     // Ensure the anchor is visible.  If that is not possible, show the panel
     // anchored to the top area of the window, near the default anchor position.
     DownloadsButton.getAnchor(function DP_OPIDR_callback(aAnchor) {
       // If somehow we've switched states already (by getting a panel hiding
       // event before an overlay is loaded, for example), bail out.
       if (this._state != this.kStateWaitingAnchor)
         return;
       // At this point, if the window is minimized, opening the panel could fail
       // without any notification, and there would be no way to either open or
       // close the panel anymore.  To prevent this, check if the window is
       // minimized and in that case force the panel to the closed state.
       if (window.windowState == Ci.nsIDOMChromeWindow.STATE_MINIMIZED) {
         DownloadsButton.releaseAnchor();
         this._state = this.kStateHidden;
         return;
       }
       // When the panel is opened, we check if the target files of visible items
       // still exist, and update the allowed items interactions accordingly.  We
       // do these checks on a background thread, and don't prevent the panel to
       // be displayed while these checks are being performed.
       for each (let viewItem in DownloadsView._viewItems) {
         viewItem.verifyTargetExists();
       }
       if (aAnchor) {
         DownloadsCommon.log("Opening downloads panel popup.");
         this.panel.openPopup(aAnchor, "bottomcenter topright", 0, 0, false,
                              null);
       } else {
         DownloadsCommon.error("We can't find the anchor! Failure case - opening",
                               "downloads panel on TabsToolbar. We should never",
                               "get here!");
         Components.utils.reportError(
           "Downloads button cannot be found");
       }
     }.bind(this));
   }
 };
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadsOverlayLoader
 /**
  * Allows loading the downloads panel and the status indicator interfaces on
  * demand, to improve startup performance.
  */
 const DownloadsOverlayLoader = {
   /**
    * We cannot load two overlays at the same time, thus we use a queue of
    * pending load requests.
    */
   _loadRequests: [],
   /**
    * True while we are waiting for an overlay to be loaded.
    */
   _overlayLoading: false,
   /**
    * This object has a key for each overlay URI that is already loaded.
    */
   _loadedOverlays: {},
   /**
    * Loads the specified overlay and invokes the given callback when finished.
    *
    * @param aOverlay
    *        String containing the URI of the overlay to load in the current
    *        window.  If this overlay has already been loaded using this
    *        function, then the overlay is not loaded again.
    * @param aCallback
    *        Invoked when loading is completed.  If the overlay is already
    *        loaded, the function is called immediately.
    */
   ensureOverlayLoaded: function DOL_ensureOverlayLoaded(aOverlay, aCallback)
   {
     // The overlay is already loaded, invoke the callback immediately.
     if (aOverlay in this._loadedOverlays) {
       aCallback();
       return;
     }
     // The callback will be invoked when loading is finished.
     this._loadRequests.push({ overlay: aOverlay, callback: aCallback });
     if (this._overlayLoading) {
       return;
     }
     function DOL_EOL_loadCallback() {
       this._overlayLoading = false;
       this._loadedOverlays[aOverlay] = true;
       this.processPendingRequests();
     }
     this._overlayLoading = true;
     DownloadsCommon.log("Loading overlay ", aOverlay);
     document.loadOverlay(aOverlay, DOL_EOL_loadCallback.bind(this));
   },
   /**
    * Re-processes all the currently pending requests, invoking the callbacks
    * and/or loading more overlays as needed.  In most cases, there will be a
    * single request for one overlay, that will be processed immediately.
    */
   processPendingRequests: function DOL_processPendingRequests()
   {
     // Re-process all the currently pending requests, yet allow more requests
     // to be appended at the end of the array if we're not ready for them.
     let currentLength = this._loadRequests.length;
     for (let i = 0; i < currentLength; i++) {
       let request = this._loadRequests.shift();
       // We must call ensureOverlayLoaded again for each request, to check if
       // the associated callback can be invoked now, or if we must still wait
       // for the associated overlay to load.
       this.ensureOverlayLoaded(request.overlay, request.callback);
     }
   }
 };
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadsView
 /**
  * Builds and updates the downloads list widget, responding to changes in the
  * download state and real-time data.  In addition, handles part of the user
  * interaction events raised by the downloads list widget.
  */
 const DownloadsView = {
   //////////////////////////////////////////////////////////////////////////////
   //// Functions handling download items in the list
   /**
    * Maximum number of items shown by the list at any given time.
    */
   kItemCountLimit: 3,
   /**
    * Indicates whether we are still loading downloads data asynchronously.
    */
   loading: false,
   /**
    * Ordered array of all DownloadsDataItem objects.  We need to keep this array
    * because only a limited number of items are shown at once, and if an item
    * that is currently visible is removed from the list, we might need to take
    * another item from the array and make it appear at the bottom.
    */
   _dataItems: [],
   /**
    * Object containing the available DownloadsViewItem objects, indexed by their
    * numeric download identifier.  There is a limited number of view items in
    * the panel at any given time.
    */
   _viewItems: {},
   /**
    * Called when the number of items in the list changes.
    */
   _itemCountChanged: function DV_itemCountChanged()
   {
     DownloadsCommon.log("The downloads item count has changed - we are tracking",
                         this._dataItems.length, "downloads in total.");
     let count = this._dataItems.length;
     let hiddenCount = count - this.kItemCountLimit;
     if (count > 0) {
       DownloadsCommon.log("Setting the panel's hasdownloads attribute to true.");
       DownloadsPanel.panel.setAttribute("hasdownloads", "true");
     } else {
       DownloadsCommon.log("Removing the panel's hasdownloads attribute.");
       DownloadsPanel.panel.removeAttribute("hasdownloads");
     }
     // If we've got some hidden downloads, we should activate the
     // DownloadsSummary. The DownloadsSummary will determine whether or not
     // it's appropriate to actually display the summary.
     DownloadsSummary.active = hiddenCount > 0;
   },
   /**
    * Element corresponding to the list of downloads.
    */
   get richListBox()
   {
     delete this.richListBox;
     return this.richListBox = document.getElementById("downloadsListBox");
   },
   /**
    * Element corresponding to the button for showing more downloads.
    */
   get downloadsHistory()
   {
     delete this.downloadsHistory;
     return this.downloadsHistory = document.getElementById("downloadsHistory");
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Callback functions from DownloadsData
   /**
    * Called before multiple downloads are about to be loaded.
    */
   onDataLoadStarting: function DV_onDataLoadStarting()
   {
     DownloadsCommon.log("onDataLoadStarting called for DownloadsView.");
     this.loading = true;
   },
   /**
    * Called after data loading finished.
    */
   onDataLoadCompleted: function DV_onDataLoadCompleted()
   {
     DownloadsCommon.log("onDataLoadCompleted called for DownloadsView.");
     this.loading = false;
     // We suppressed item count change notifications during the batch load, at
     // this point we should just call the function once.
     this._itemCountChanged();
     // Notify the panel that all the initially available downloads have been
     // loaded.  This ensures that the interface is visible, if still required.
     DownloadsPanel.onViewLoadCompleted();
   },
   /**
    * Called when a new download data item is available, either during the
    * asynchronous data load or when a new download is started.
    *
    * @param aDataItem
    *        DownloadsDataItem object that was just added.
    * @param aNewest
    *        When true, indicates that this item is the most recent and should be
    *        added in the topmost position.  This happens when a new download is
    *        started.  When false, indicates that the item is the least recent
    *        and should be appended.  The latter generally happens during the
    *        asynchronous data load.
    */
   onDataItemAdded: function DV_onDataItemAdded(aDataItem, aNewest)
   {
     DownloadsCommon.log("A new download data item was added - aNewest =",
                         aNewest);
     if (aNewest) {
       this._dataItems.unshift(aDataItem);
     } else {
       this._dataItems.push(aDataItem);
     }
     let itemsNowOverflow = this._dataItems.length > this.kItemCountLimit;
     if (aNewest || !itemsNowOverflow) {
       // The newly added item is visible in the panel and we must add the
       // corresponding element.  This is either because it is the first item, or
       // because it was added at the bottom but the list still doesn't overflow.
       this._addViewItem(aDataItem, aNewest);
     }
     if (aNewest && itemsNowOverflow) {
       // If the list overflows, remove the last item from the panel to make room
       // for the new one that we just added at the top.
       this._removeViewItem(this._dataItems[this.kItemCountLimit]);
     }
     // For better performance during batch loads, don't update the count for
     // every item, because the interface won't be visible until load finishes.
     if (!this.loading) {
       this._itemCountChanged();
     }
   },
   /**
    * Called when a data item is removed.  Ensures that the widget associated
    * with the view item is removed from the user interface.
    *
    * @param aDataItem
    *        DownloadsDataItem object that is being removed.
    */
   onDataItemRemoved: function DV_onDataItemRemoved(aDataItem)
   {
     DownloadsCommon.log("A download data item was removed.");
     let itemIndex = this._dataItems.indexOf(aDataItem);
     this._dataItems.splice(itemIndex, 1);
     if (itemIndex < this.kItemCountLimit) {
       // The item to remove is visible in the panel.
       this._removeViewItem(aDataItem);
       if (this._dataItems.length >= this.kItemCountLimit) {
         // Reinsert the next item into the panel.
         this._addViewItem(this._dataItems[this.kItemCountLimit - 1], false);
       }
     }
     this._itemCountChanged();
   },
   /**
    * Returns the view item associated with the provided data item for this view.
    *
    * @param aDataItem
    *        DownloadsDataItem object for which the view item is requested.
    *
    * @return Object that can be used to notify item status events.
    */
   getViewItem: function DV_getViewItem(aDataItem)
   {
     // If the item is visible, just return it, otherwise return a mock object
     // that doesn't react to notifications.
     if (aDataItem.downloadGuid in this._viewItems) {
       return this._viewItems[aDataItem.downloadGuid];
     }
     return this._invisibleViewItem;
   },
   /**
    * Mock DownloadsDataItem object that doesn't react to notifications.
    */
   _invisibleViewItem: Object.freeze({
     onStateChange: function () { },
     onProgressChange: function () { }
   }),
   /**
    * Creates a new view item associated with the specified data item, and adds
    * it to the top or the bottom of the list.
    */
   _addViewItem: function DV_addViewItem(aDataItem, aNewest)
   {
     DownloadsCommon.log("Adding a new DownloadsViewItem to the downloads list.",
                         "aNewest =", aNewest);
     let element = document.createElement("richlistitem");
     let viewItem = new DownloadsViewItem(aDataItem, element);
     this._viewItems[aDataItem.downloadGuid] = viewItem;
     if (aNewest) {
       this.richListBox.insertBefore(element, this.richListBox.firstChild);
     } else {
       this.richListBox.appendChild(element);
     }
   },
   /**
    * Removes the view item associated with the specified data item.
    */
   _removeViewItem: function DV_removeViewItem(aDataItem)
   {
     DownloadsCommon.log("Removing a DownloadsViewItem from the downloads list.");
     let element = this.getViewItem(aDataItem)._element;
     let previousSelectedIndex = this.richListBox.selectedIndex;
     this.richListBox.removeChild(element);
     if (previousSelectedIndex != -1) {
       this.richListBox.selectedIndex = Math.min(previousSelectedIndex,
                                                 this.richListBox.itemCount - 1);
     }
     delete this._viewItems[aDataItem.downloadGuid];
   },
   //////////////////////////////////////////////////////////////////////////////
   //// User interface event functions
   /**
    * Helper function to do commands on a specific download item.
    *
    * @param aEvent
    *        Event object for the event being handled.  If the event target is
    *        not a richlistitem that represents a download, this function will
    *        walk up the parent nodes until it finds a DOM node that is.
    * @param aCommand
    *        The command to be performed.
    */
   onDownloadCommand: function DV_onDownloadCommand(aEvent, aCommand)
   {
     let target = aEvent.target;
     while (target.nodeName != "richlistitem") {
       target = target.parentNode;
     }
     new DownloadsViewItemController(target).doCommand(aCommand);
   },
   onDownloadClick: function DV_onDownloadClick(aEvent)
   {
     // Handle primary clicks only, and exclude the action button.
     if (aEvent.button == 0 &&
         !aEvent.originalTarget.hasAttribute("oncommand")) {
       goDoCommand("downloadsCmd_open");
     }
   },
   /**
    * Handles keypress events on a download item.
    */
   onDownloadKeyPress: function DV_onDownloadKeyPress(aEvent)
   {
     // Pressing the key on buttons should not invoke the action because the
     // event has already been handled by the button itself.
     if (aEvent.originalTarget.hasAttribute("command") ||
         aEvent.originalTarget.hasAttribute("oncommand")) {
       return;
     }
     if (aEvent.charCode == " ".charCodeAt(0)) {
       goDoCommand("downloadsCmd_pauseResume");
       return;
     }
     if (aEvent.keyCode == KeyEvent.DOM_VK_RETURN) {
       goDoCommand("downloadsCmd_doDefault");
     }
   },
   /**
    * Mouse listeners to handle selection on hover.
    */
   onDownloadMouseOver: function DV_onDownloadMouseOver(aEvent)
   {
     if (aEvent.originalTarget.parentNode == this.richListBox)
       this.richListBox.selectedItem = aEvent.originalTarget;
   },
   onDownloadMouseOut: function DV_onDownloadMouseOut(aEvent)
   {
     if (aEvent.originalTarget.parentNode == this.richListBox) {
       // If the destination element is outside of the richlistitem, clear the
       // selection.
       let element = aEvent.relatedTarget;
       while (element && element != aEvent.originalTarget) {
         element = element.parentNode;
       }
       if (!element)
         this.richListBox.selectedIndex = -1;
     }
   },
   onDownloadContextMenu: function DV_onDownloadContextMenu(aEvent)
   {
     let element = this.richListBox.selectedItem;
     if (!element) {
       return;
     }
     DownloadsViewController.updateCommands();
     // Set the state attribute so that only the appropriate items are displayed.
     let contextMenu = document.getElementById("downloadsContextMenu");
     contextMenu.setAttribute("state", element.getAttribute("state"));
   },
   onDownloadDragStart: function DV_onDownloadDragStart(aEvent)
   {
     let element = this.richListBox.selectedItem;
     if (!element) {
       return;
     }
     let controller = new DownloadsViewItemController(element);
     let localFile = controller.dataItem.localFile;
     if (!localFile.exists()) {
       return;
     }
     let dataTransfer = aEvent.dataTransfer;
     dataTransfer.mozSetDataAt("application/x-moz-file", localFile, 0);
     dataTransfer.effectAllowed = "copyMove";
     var url = Services.io.newFileURI(localFile).spec;
     dataTransfer.setData("text/uri-list", url);
     dataTransfer.setData("text/plain", url);
     dataTransfer.addElement(element);
     aEvent.stopPropagation();
   }
 }
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadsViewItem
 /**
  * Builds and updates a single item in the downloads list widget, responding to
  * changes in the download state and real-time data.
  *
  * @param aDataItem
  *        DownloadsDataItem to be associated with the view item.
  * @param aElement
  *        XUL element corresponding to the single download item in the view.
  */
 function DownloadsViewItem(aDataItem, aElement)
 {
   this._element = aElement;
   this.dataItem = aDataItem;
   this.lastEstimatedSecondsLeft = Infinity;
   // Set the URI that represents the correct icon for the target file.  As soon
   // as bug 239948 comment 12 is handled, the "file" property will be always a
   // file URL rather than a file name.  At that point we should remove the "//"
   // (double slash) from the icon URI specification (see test_moz_icon_uri.js).
   this.image = "moz-icon://" + this.dataItem.file + "?size=32";
   let attributes = {
     "type": "download",
     "class": "download-state",
     "id": "downloadsItem_" + this.dataItem.downloadGuid,
     "downloadGuid": this.dataItem.downloadGuid,
     "state": this.dataItem.state,
     "progress": this.dataItem.inProgress ? this.dataItem.percentComplete : 100,
     "target": this.dataItem.target,
     "image": this.image
   };
   for (let attributeName in attributes) {
     this._element.setAttribute(attributeName, attributes[attributeName]);
   }
   // Initialize more complex attributes.
   this._updateProgress();
   this._updateStatusLine();
   this.verifyTargetExists();
 }
 DownloadsViewItem.prototype = {
   /**
    * The DownloadDataItem associated with this view item.
    */
   dataItem: null,
   /**
    * The XUL element corresponding to the associated richlistbox item.
    */
   _element: null,
   /**
    * The inner XUL element for the progress bar, or null if not available.
    */
   _progressElement: null,
   //////////////////////////////////////////////////////////////////////////////
   //// Callback functions from DownloadsData
   /**
    * Called when the download state might have changed.  Sometimes the state of
    * the download might be the same as before, if the data layer received
    * multiple events for the same download.
    */
   onStateChange: function DVI_onStateChange(aOldState)
   {
     // If a download just finished successfully, it means that the target file
     // now exists and we can extract its specific icon.  To ensure that the icon
     // is reloaded, we must change the URI used by the XUL image element, for
     // example by adding a query parameter.  Since this URI has a "moz-icon"
     // scheme, this only works if we add one of the parameters explicitly
     // supported by the nsIMozIconURI interface.
     if (aOldState != Ci.nsIDownloadManager.DOWNLOAD_FINISHED &&
         aOldState != this.dataItem.state) {
       this._element.setAttribute("image", this.image + "&state=normal");
       // We assume the existence of the target of a download that just completed
       // successfully, without checking the condition in the background.  If the
       // panel is already open, this will take effect immediately.  If the panel
       // is opened later, a new background existence check will be performed.
       this._element.setAttribute("exists", "true");
     }
     // Update the user interface after switching states.
     this._element.setAttribute("state", this.dataItem.state);
     this._updateProgress();
     this._updateStatusLine();
   },
   /**
    * Called when the download progress has changed.
    */
   onProgressChange: function DVI_onProgressChange() {
     this._updateProgress();
     this._updateStatusLine();
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Functions for updating the user interface
   /**
    * Updates the progress bar.
    */
   _updateProgress: function DVI_updateProgress() {
     if (this.dataItem.starting) {
       // Before the download starts, the progress meter has its initial value.
       this._element.setAttribute("progressmode", "normal");
       this._element.setAttribute("progress", "0");
     } else if (this.dataItem.state == Ci.nsIDownloadManager.DOWNLOAD_SCANNING ||
                this.dataItem.percentComplete == -1) {
       // We might not know the progress of a running download, and we don't know
       // the remaining time during the malware scanning phase.
       this._element.setAttribute("progressmode", "undetermined");
     } else {
       // This is a running download of which we know the progress.
       this._element.setAttribute("progressmode", "normal");
       this._element.setAttribute("progress", this.dataItem.percentComplete);
     }
     // Find the progress element as soon as the download binding is accessible.
     if (!this._progressElement) {
       this._progressElement =
            document.getAnonymousElementByAttribute(this._element, "anonid",
                                                    "progressmeter");
     }
     // Dispatch the ValueChange event for accessibility, if possible.
     if (this._progressElement) {
       let event = document.createEvent("Events");
       event.initEvent("ValueChange", true, true);
       this._progressElement.dispatchEvent(event);
     }
   },
   /**
    * Updates the main status line, including bytes transferred, bytes total,
    * download rate, and time remaining.
    */
   _updateStatusLine: function DVI_updateStatusLine() {
     const nsIDM = Ci.nsIDownloadManager;
     let status = "";
     let statusTip = "";
     if (this.dataItem.paused) {
       let transfer = DownloadUtils.getTransferTotal(this.dataItem.currBytes,
                                                     this.dataItem.maxBytes);
       // We use the same XUL label to display both the state and the amount
       // transferred, for example "Paused -  1.1 MB".
       status = DownloadsCommon.strings.statusSeparatorBeforeNumber(
                                             DownloadsCommon.strings.statePaused,
                                             transfer);
     } else if (this.dataItem.state == nsIDM.DOWNLOAD_DOWNLOADING) {
       // We don't show the rate for each download in order to reduce clutter.
       // The remaining time per download is likely enough information for the
       // panel.
       [status] =
         DownloadUtils.getDownloadStatusNoRate(this.dataItem.currBytes,
                                               this.dataItem.maxBytes,
                                               this.dataItem.speed,
                                               this.lastEstimatedSecondsLeft);
       // We are, however, OK with displaying the rate in the tooltip.
       let newEstimatedSecondsLeft;
       [statusTip, newEstimatedSecondsLeft] =
         DownloadUtils.getDownloadStatus(this.dataItem.currBytes,
                                         this.dataItem.maxBytes,
                                         this.dataItem.speed,
                                         this.lastEstimatedSecondsLeft);
       this.lastEstimatedSecondsLeft = newEstimatedSecondsLeft;
     } else if (this.dataItem.starting) {
       status = DownloadsCommon.strings.stateStarting;
     } else if (this.dataItem.state == nsIDM.DOWNLOAD_SCANNING) {
       status = DownloadsCommon.strings.stateScanning;
     } else if (!this.dataItem.inProgress) {
       let stateLabel = function () {
         let s = DownloadsCommon.strings;
         switch (this.dataItem.state) {
           case nsIDM.DOWNLOAD_FAILED:           return s.stateFailed;
           case nsIDM.DOWNLOAD_CANCELED:         return s.stateCanceled;
           case nsIDM.DOWNLOAD_BLOCKED_PARENTAL: return s.stateBlockedParentalControls;
           case nsIDM.DOWNLOAD_BLOCKED_POLICY:   return s.stateBlockedPolicy;
           case nsIDM.DOWNLOAD_DIRTY:            return s.stateDirty;
           case nsIDM.DOWNLOAD_FINISHED:         return this._fileSizeText;
         }
         return null;
       }.apply(this);
       let [displayHost, fullHost] =
         DownloadUtils.getURIHost(this.dataItem.referrer || this.dataItem.uri);
       let end = new Date(this.dataItem.endTime);
       let [displayDate, fullDate] = DownloadUtils.getReadableDates(end);
       // We use the same XUL label to display the state, the host name, and the
       // end time, for example "Canceled - 222.net - 11:15" or "1.1 MB -
       // website2.com - Yesterday".  We show the full host and the complete date
       // in the tooltip.
       let firstPart = DownloadsCommon.strings.statusSeparator(stateLabel,
                                                               displayHost);
       status = DownloadsCommon.strings.statusSeparator(firstPart, displayDate);
       statusTip = DownloadsCommon.strings.statusSeparator(fullHost, fullDate);
     }
     this._element.setAttribute("status", status);
     this._element.setAttribute("statusTip", statusTip || status);
   },
   /**
    * Localized string representing the total size of completed downloads, for
    * example "1.5 MB" or "Unknown size".
    */
   get _fileSizeText()
   {
     // Display the file size, but show "Unknown" for negative sizes.
     let fileSize = this.dataItem.maxBytes;
     if (fileSize < 0) {
       return DownloadsCommon.strings.sizeUnknown;
     }
     let [size, unit] = DownloadUtils.convertByteUnits(fileSize);
     return DownloadsCommon.strings.sizeWithUnits(size, unit);
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Functions called by the panel
   /**
    * Starts checking whether the target file of a finished download is still
    * available on disk, and sets an attribute that controls how the item is
    * presented visually.
    *
    * The existence check is executed on a background thread.
    */
   verifyTargetExists: function DVI_verifyTargetExists() {
     // We don't need to check if the download is not finished successfully.
     if (!this.dataItem.openable) {
       return;
     }
     OS.File.exists(this.dataItem.localFile.path).then(
       function DVI_RTE_onSuccess(aExists) {
         if (aExists) {
           this._element.setAttribute("exists", "true");
         } else {
           this._element.removeAttribute("exists");
         }
       }.bind(this), Cu.reportError);
   },
 };
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadsViewController
 /**
  * Handles part of the user interaction events raised by the downloads list
  * widget, in particular the "commands" that apply to multiple items, and
  * dispatches the commands that apply to individual items.
  */
 const DownloadsViewController = {
   //////////////////////////////////////////////////////////////////////////////
   //// Initialization and termination
   initialize: function DVC_initialize()
   {
     window.controllers.insertControllerAt(0, this);
   },
   terminate: function DVC_terminate()
   {
     window.controllers.removeController(this);
   },
   //////////////////////////////////////////////////////////////////////////////
   //// nsIController
   supportsCommand: function DVC_supportsCommand(aCommand)
   {
     // Firstly, determine if this is a command that we can handle.
     if (!(aCommand in this.commands) &&
         !(aCommand in DownloadsViewItemController.prototype.commands)) {
       return false;
     }
     // Secondly, determine if focus is on a control in the downloads list.
     let element = document.commandDispatcher.focusedElement;
     while (element && element != DownloadsView.richListBox) {
       element = element.parentNode;
     }
     // We should handle the command only if the downloads list is among the
     // ancestors of the focused element.
     return !!element;
   },
   isCommandEnabled: function DVC_isCommandEnabled(aCommand)
   {
     // Handle commands that are not selection-specific.
     if (aCommand == "downloadsCmd_clearList") {
       return DownloadsCommon.getData(window).canRemoveFinished;
     }
     // Other commands are selection-specific.
     let element = DownloadsView.richListBox.selectedItem;
     return element &&
            new DownloadsViewItemController(element).isCommandEnabled(aCommand);
   },
   doCommand: function DVC_doCommand(aCommand)
   {
     // If this command is not selection-specific, execute it.
     if (aCommand in this.commands) {
       this.commands[aCommand].apply(this);
       return;
     }
     // Other commands are selection-specific.
     let element = DownloadsView.richListBox.selectedItem;
     if (element) {
       // The doCommand function also checks if the command is enabled.
       new DownloadsViewItemController(element).doCommand(aCommand);
     }
   },
   onEvent: function () { },
   //////////////////////////////////////////////////////////////////////////////
   //// Other functions
   updateCommands: function DVC_updateCommands()
   {
     Object.keys(this.commands).forEach(goUpdateCommand);
     Object.keys(DownloadsViewItemController.prototype.commands)
           .forEach(goUpdateCommand);
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Selection-independent commands
   /**
    * This object contains one key for each command that operates regardless of
    * the currently selected item in the list.
    */
   commands: {
     downloadsCmd_clearList: function DVC_downloadsCmd_clearList()
     {
       DownloadsCommon.getData(window).removeFinished();
     }
   }
 };
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadsViewItemController
 /**
  * Handles all the user interaction events, in particular the "commands",
  * related to a single item in the downloads list widgets.
  */
 function DownloadsViewItemController(aElement) {
   let downloadGuid = aElement.getAttribute("downloadGuid");
   this.dataItem = DownloadsCommon.getData(window).dataItems[downloadGuid];
 }
 DownloadsViewItemController.prototype = {
   //////////////////////////////////////////////////////////////////////////////
   //// Command dispatching
   /**
    * The DownloadDataItem controlled by this object.
    */
   dataItem: null,
   isCommandEnabled: function DVIC_isCommandEnabled(aCommand)
   {
     switch (aCommand) {
       case "downloadsCmd_open": {
         return this.dataItem.openable && this.dataItem.localFile.exists();
       }
       case "downloadsCmd_show": {
         return this.dataItem.localFile.exists() ||
                this.dataItem.partFile.exists();
       }
       case "downloadsCmd_pauseResume":
         return this.dataItem.inProgress && this.dataItem.resumable;
       case "downloadsCmd_retry":
         return this.dataItem.canRetry;
       case "downloadsCmd_openReferrer":
         return !!this.dataItem.referrer;
       case "cmd_delete":
       case "downloadsCmd_cancel":
       case "downloadsCmd_copyLocation":
       case "downloadsCmd_doDefault":
         return true;
     }
     return false;
   },
   doCommand: function DVIC_doCommand(aCommand)
   {
     if (this.isCommandEnabled(aCommand)) {
       this.commands[aCommand].apply(this);
     }
   },
   //////////////////////////////////////////////////////////////////////////////
   //// Item commands
   /**
    * This object contains one key for each command that operates on this item.
    *
    * In commands, the "this" identifier points to the controller item.
    */
   commands: {
     cmd_delete: function DVIC_cmd_delete()
     {
       this.dataItem.remove();
       PlacesUtils.bhistory.removePage(NetUtil.newURI(this.dataItem.uri));
     },
     downloadsCmd_cancel: function DVIC_downloadsCmd_cancel()
     {
       this.dataItem.cancel();
     },
     downloadsCmd_open: function DVIC_downloadsCmd_open()
     {
       this.dataItem.openLocalFile();
       // We explicitly close the panel here to give the user the feedback that
       // their click has been received, and we're handling the action.
       // Otherwise, we'd have to wait for the file-type handler to execute
       // before the panel would close. This also helps to prevent the user from
       // accidentally opening a file several times.
       DownloadsPanel.hidePanel();
     },
     downloadsCmd_show: function DVIC_downloadsCmd_show()
     {
       this.dataItem.showLocalFile();
       // We explicitly close the panel here to give the user the feedback that
       // their click has been received, and we're handling the action.
       // Otherwise, we'd have to wait for the operating system file manager
       // window to open before the panel closed. This also helps to prevent the
       // user from opening the containing folder several times.
       DownloadsPanel.hidePanel();
     },
     downloadsCmd_pauseResume: function DVIC_downloadsCmd_pauseResume()
     {
       this.dataItem.togglePauseResume();
     },
     downloadsCmd_retry: function DVIC_downloadsCmd_retry()
     {
       this.dataItem.retry();
     },
     downloadsCmd_openReferrer: function DVIC_downloadsCmd_openReferrer()
     {
       openURL(this.dataItem.referrer);
     },
     downloadsCmd_copyLocation: function DVIC_downloadsCmd_copyLocation()
     {
       let clipboard = Cc["@mozilla.org/widget/clipboardhelper;1"]
                       .getService(Ci.nsIClipboardHelper);
       clipboard.copyString(this.dataItem.uri, document);
     },
     downloadsCmd_doDefault: function DVIC_downloadsCmd_doDefault()
     {
       const nsIDM = Ci.nsIDownloadManager;
       // Determine the default command for the current item.
       let defaultCommand = function () {
         switch (this.dataItem.state) {
           case nsIDM.DOWNLOAD_NOTSTARTED:       return "downloadsCmd_cancel";
           case nsIDM.DOWNLOAD_FINISHED:         return "downloadsCmd_open";
           case nsIDM.DOWNLOAD_FAILED:           return "downloadsCmd_retry";
           case nsIDM.DOWNLOAD_CANCELED:         return "downloadsCmd_retry";
           case nsIDM.DOWNLOAD_PAUSED:           return "downloadsCmd_pauseResume";
           case nsIDM.DOWNLOAD_QUEUED:           return "downloadsCmd_cancel";
           case nsIDM.DOWNLOAD_BLOCKED_PARENTAL: return "downloadsCmd_openReferrer";
           case nsIDM.DOWNLOAD_SCANNING:         return "downloadsCmd_show";
           case nsIDM.DOWNLOAD_DIRTY:            return "downloadsCmd_openReferrer";
           case nsIDM.DOWNLOAD_BLOCKED_POLICY:   return "downloadsCmd_openReferrer";
         }
         return "";
       }.apply(this);
       if (defaultCommand && this.isCommandEnabled(defaultCommand))
         this.doCommand(defaultCommand);
     }
   }
 };
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadsSummary
 /**
  * Manages the summary at the bottom of the downloads panel list if the number
  * of items in the list exceeds the panels limit.
  */
 const DownloadsSummary = {
   /**
    * Sets the active state of the summary. When active, the summary subscribes
    * to the DownloadsCommon DownloadsSummaryData singleton.
    *
    * @param aActive
    *        Set to true to activate the summary.
    */
   set active(aActive)
   {
     if (aActive == this._active || !this._summaryNode) {
       return this._active;
     }
     if (aActive) {
       DownloadsCommon.getSummary(window, DownloadsView.kItemCountLimit)
                      .refreshView(this);
     } else {
       DownloadsFooter.showingSummary = false;
     }
     return this._active = aActive;
   },
   /**
    * Returns the active state of the downloads summary.
    */
   get active() this._active,
   _active: false,
   /**
    * Sets whether or not we show the progress bar.
    *
    * @param aShowingProgress
    *        True if we should show the progress bar.
    */
   set showingProgress(aShowingProgress)
   {
     if (aShowingProgress) {
       this._summaryNode.setAttribute("inprogress", "true");
     } else {
       this._summaryNode.removeAttribute("inprogress");
     }
     // If progress isn't being shown, then we simply do not show the summary.
     return DownloadsFooter.showingSummary = aShowingProgress;
   },
   /**
    * Sets the amount of progress that is visible in the progress bar.
    *
    * @param aValue
    *        A value between 0 and 100 to represent the progress of the
    *        summarized downloads.
    */
   set percentComplete(aValue)
   {
     if (this._progressNode) {
       this._progressNode.setAttribute("value", aValue);
     }
     return aValue;
   },
   /**
    * Sets the description for the download summary.
    *
    * @param aValue
    *        A string representing the description of the summarized
    *        downloads.
    */
   set description(aValue)
   {
     if (this._descriptionNode) {
       this._descriptionNode.setAttribute("value", aValue);
       this._descriptionNode.setAttribute("tooltiptext", aValue);
     }
     return aValue;
   },
   /**
    * Sets the details for the download summary, such as the time remaining,
    * the amount of bytes transferred, etc.
    *
    * @param aValue
    *        A string representing the details of the summarized
    *        downloads.
    */
   set details(aValue)
   {
     if (this._detailsNode) {
       this._detailsNode.setAttribute("value", aValue);
       this._detailsNode.setAttribute("tooltiptext", aValue);
     }
     return aValue;
   },
   /**
    * Focuses the root element of the summary.
    */
   focus: function()
   {
     if (this._summaryNode) {
       this._summaryNode.focus();
     }
   },
   /**
    * Respond to keydown events on the Downloads Summary node.
    *
    * @param aEvent
    *        The keydown event being handled.
    */
   onKeyDown: function DS_onKeyDown(aEvent)
   {
     if (aEvent.charCode == " ".charCodeAt(0) ||
         aEvent.keyCode == KeyEvent.DOM_VK_RETURN) {
       DownloadsPanel.showDownloadsHistory();
     }
   },
   /**
    * Respond to click events on the Downloads Summary node.
    *
    * @param aEvent
    *        The click event being handled.
    */
   onClick: function DS_onClick(aEvent)
   {
     DownloadsPanel.showDownloadsHistory();
   },
   /**
    * Element corresponding to the root of the downloads summary.
    */
   get _summaryNode()
   {
     let node = document.getElementById("downloadsSummary");
     if (!node) {
       return null;
     }
     delete this._summaryNode;
     return this._summaryNode = node;
   },
   /**
    * Element corresponding to the progress bar in the downloads summary.
    */
   get _progressNode()
   {
     let node = document.getElementById("downloadsSummaryProgress");
     if (!node) {
       return null;
     }
     delete this._progressNode;
     return this._progressNode = node;
   },
   /**
    * Element corresponding to the main description of the downloads
    * summary.
    */
   get _descriptionNode()
   {
     let node = document.getElementById("downloadsSummaryDescription");
     if (!node) {
       return null;
     }
     delete this._descriptionNode;
     return this._descriptionNode = node;
   },
   /**
    * Element corresponding to the secondary description of the downloads
    * summary.
    */
   get _detailsNode()
   {
     let node = document.getElementById("downloadsSummaryDetails");
     if (!node) {
       return null;
     }
     delete this._detailsNode;
     return this._detailsNode = node;
   }
 }
 ////////////////////////////////////////////////////////////////////////////////
 //// DownloadsFooter
 /**
  * Manages events sent to to the footer vbox, which contains both the
  * DownloadsSummary as well as the "Show All Downloads" button.
  */
 const DownloadsFooter = {
   /**
    * Focuses the appropriate element within the footer. If the summary
    * is visible, focus it. If not, focus the "Show All Downloads"
    * button.
    */
   focus: function DF_focus()
   {
     if (this._showingSummary) {
       DownloadsSummary.focus();
     } else {
       DownloadsView.downloadsHistory.focus();
     }
   },
   _showingSummary: false,
   /**
    * Sets whether or not the Downloads Summary should be displayed in the
    * footer. If not, the "Show All Downloads" button is shown instead.
    */
   set showingSummary(aValue)
   {
     if (this._footerNode) {
       if (aValue) {
         this._footerNode.setAttribute("showingsummary", "true");
       } else {
         this._footerNode.removeAttribute("showingsummary");
       }
       this._showingSummary = aValue;
     }
     return aValue;
   },
   /**
    * Element corresponding to the footer of the downloads panel.
    */
   get _footerNode()
   {
     let node = document.getElementById("downloadsFooter");
     if (!node) {
       return null;
     }
     delete this._footerNode;
     return this._footerNode = node;
   }
 };