Add Pale Moon

1 files changed, 1813 insertions, 0 deletions

diff --git a/application/palemoon/components/downloads/content/downloads.js b/application/palemoon/components/downloads/content/downloads.js
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+++ b/application/palemoon/components/downloads/content/downloads.js
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+/* -*- 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);
+
+    // Ensure that the Download Manager service is running.  This resumes
+    // active downloads if required.  If there are downloads to be shown in the
+    // panel, starting the service will make us load their data 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 resetting 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.");
+      saveURL(uri.spec, name || uri.spec, null, true, true,
+              undefined, 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 any more.  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;
+
+      // Loading the overlay causes all the persisted XUL attributes to be
+      // reapplied, including "iconsize" on the toolbars.  Until bug 640158 is
+      // fixed, we must recalculate the correct "iconsize" attributes manually.
+      retrieveToolbarIconsizesFromTheme();
+
+      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 the downloads database becomes unavailable (for example,
+   * entering Private Browsing Mode).  References to existing data should be
+   * discarded.
+   */
+  onDataInvalidated: function DV_onDataInvalidated()
+  {
+    DownloadsCommon.log("Downloads data has been invalidated. Cleaning up",
+                        "DownloadsView.");
+
+    DownloadsPanel.terminate();
+
+    // Clear the list by replacing with a shallow copy.
+    let emptyView = this.richListBox.cloneNode(false);
+    this.richListBox.parentNode.replaceChild(emptyView, this.richListBox);
+    this.richListBox = emptyView;
+    this._viewItems = {};
+    this._dataItems = [];
+  },
+
+  /**
+   * 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_ENTER ||
+        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 s = DownloadsCommon.strings;
+  let [displayHost, fullHost] =
+    DownloadUtils.getURIHost(this.dataItem.referrer || this.dataItem.uri);
+
+  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,
+    "displayName": this.dataItem.target,
+    "extendedDisplayName": s.statusSeparator(this.dataItem.target, displayHost),
+    "extendedDisplayNameTip": s.statusSeparator(this.dataItem.target, fullHost),
+    "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()
+    {
+      Downloads.getList(Downloads.ALL)
+               .then(list => list.remove(this.dataItem._download))
+               .then(() => this.dataItem._download.finalize(true))
+               .catch(Cu.reportError);
+      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(window);
+      // 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_ENTER ||
+        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;
+  }
+};