return "";    },    getImageSrc: function (aIndex, aColumn)     {      if (aColumn.id == "fileExtension")         return this.getItemAtIndex(aIndex).smallIcon;      return "";    },    _selection: null,     get selection () { return this._selection; },    set selection (val) { this._selection = val; return val; },    getRowProperties: function (aIndex, aProperties) {},    getCellProperties: function (aIndex, aColumn, aProperties) {},    getColumnProperties: function (aColumn, aProperties) {},    isContainer: function (aIndex) { return false; },    isContainerOpen: function (aIndex) { return false; },    isContainerEmpty: function (aIndex) { return false; },    isSeparator: function (aIndex) { return false; },    isSorted: function (aIndex) { return false; },    canDrop: function (aIndex, aOrientation) { return false; },    drop: function (aIndex, aOrientation) {},    getParentIndex: function (aIndex) { return -1; },    hasNextSibling: function (aParentIndex, aIndex) { return false; },    getLevel: function (aIndex) { return 0; },    getProgressMode: function (aIndex, aColumn) {},        getCellValue: function (aIndex, aColumn) {},    setTree: function (aTree) {},        toggleOpenState: function (aIndex) { },    cycleHeader: function (aColumn) {},        selectionChanged: function () {},        cycleCell: function (aIndex, aColumn) {},        isEditable: function (aIndex, aColumn) { return false; },    setCellValue: function (aIndex, aColumn, aValue) {},        setCellText: function (aIndex, aColumn, aValue) {},        performAction: function (aAction) {},      performActionOnRow: function (aAction, aIndex) {},        performActionOnCell: function (aAction, aindex, aColumn) {}  },  removeFileHandler: function ()  {    var selection = this._tree.view.selection;     if (selection.count < 1)      return;          var promptService = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]                                  .getService(Components.interfaces.nsIPromptService);    var flags = promptService.BUTTON_TITLE_IS_STRING * promptService.BUTTON_POS_0;    flags += promptService.BUTTON_TITLE_CANCEL * promptService.BUTTON_POS_1;    var title = this._bundle.getString("removeTitle" + (selection.count > 1 ? "Multiple" : "Single"));    var message = this._bundle.getString("removeMessage" + (selection.count > 1 ? "Multiple" : "Single"));    var button = this._bundle.getString("removeButton" + (selection.count > 1 ? "Multiple" : "Single"));    rv = promptService.confirmEx(window, title, message, flags, button,                                  null, null, null, { value: 0 });    if (rv != 0)      return;         var rangeCount = selection.getRangeCount();    var lastSelected = 0;    var mimeDSDirty = false;    for (var i = 0; i < rangeCount; ++i) {      var min = { }; var max = { };      selection.getRangeAt(i, min, max);      for (var j = min.value; j <= max.value; ++j) {        var item = this._view.getItemAtIndex(j);        if (!item.handledOnlyByPlugin) {          // There is data for this type in the MIME registry, so make sure we          // remove it from the MIME registry. We don't disable the plugin here because          // if we do there's currently no way through the UI to re-enable it. We may          // come up with some sort of solution for that at a later date.           var typeRes = this._rdf.GetResource(MIME_URI(item.type));          var handlerRes = this._getChildResource(typeRes, "handlerProp");          var extAppRes = this._getChildResource(handlerRes, "externalApplication");          this._cleanResource(extAppRes);          this._cleanResource(handlerRes);          this._cleanResource(typeRes);           mimeDSDirty = true;                 }        lastSelected = (j + 1) >= this._view.rowCount ? j-1 : j;      }    }    if (mimeDSDirty &&         this._mimeDS instanceof Components.interfaces.nsIRDFRemoteDataSource)      this._mimeDS.Flush();        // Just reload the list to make sure deletions are respected    this._loadView();    this._updateRowCount(this._updateExclusions());    selection.select(lastSelected);  },    _cleanResource: function (aResource)  {    var labels = this._mimeDS.ArcLabelsOut(aResource);    while (labels.hasMoreElements()) {      var arc = labels.getNext();      if (!(arc instanceof Components.interfaces.nsIRDFResource))        break;      var target = this._mimeDS.GetTarget(aResource, arc, true);      this._mimeDS.Unassert(aResource, arc, target);    }  },    _disablePluginForItem: function (aItem)  {  },    _enablePluginForItem: function (aItem)  {  },    _ensureMIMERegistryEntry: function (aItem)  {    var root = this._rdf.GetResource("urn:mimetypes:root");    var container = Components.classes["@mozilla.org/rdf/container;1"]                              .createInstance(Components.interfaces.nsIRDFContainer);    container.Init(this._mimeDS, root);        var itemResource = this._rdf.GetResource(MIME_URI(aItem.type));    var handlerResource = null;    if (container.IndexOf(itemResource) == -1) {      container.AppendElement(itemResource);      this._setLiteralValue(itemResource, "editable", "true");      this._setLiteralValue(itemResource, "value", aItem.type);            handlerResource = this._rdf.GetResource(HANDLER_URI(aItem.type));      this._setLiteralValue(handlerResource, "alwaysAsk", "false");      var handlerProp = this._rdf.GetResource(NC_URI("handlerProp"));      this._mimeDS.Assert(itemResource, handlerProp, handlerResource, true);            var extAppResource = this._rdf.GetResource(APP_URI(aItem.type));      this._setLiteralValue(extAppResource, "path", "");      var extAppProp = this._rdf.GetResource(NC_URI("externalApplication"));      this._mimeDS.Assert(handlerResource, extAppProp, extAppResource, true);    }    else      handlerResource = this._getChildResource(itemResource, "handlerProp");            return handlerResource;  },    _setLiteralValue: function (aResource, aProperty, aValue)  {    var property = this._rdf.GetResource(NC_URI(aProperty));    var newValue = this._rdf.GetLiteral(aValue);    var oldValue = this._mimeDS.GetTarget(aResource, property, true);    if (oldValue)      this._mimeDS.Change(aResource, property, oldValue, newValue);    else      this._mimeDS.Assert(aResource, property, newValue, true);  },    editFileHandler: function ()  {    var selection = this._tree.view.selection;     if (selection.count != 1)      return;    var item = this._view.getItemAtIndex(selection.currentIndex);    openDialog("chrome://messenger/content/preferences/changeaction.xul",                "_blank", "modal,centerscreen", item);        // Update the database    switch (item.handleMode) {    case FILEACTION_OPEN_PLUGIN:      this._enablePluginForItem(item);      // We don't need to adjust the database because plugin settings always      // supercede whatever is in the db, leaving it untouched allows the last      // user setting(s) to be preserved if they ever revert.      break;    case FILEACTION_OPEN_DEFAULT:      this._disablePluginForItem(item);      var handlerRes = this._ensureMIMERegistryEntry(item);      this._setLiteralValue(handlerRes, "useSystemDefault", "true");      this._setLiteralValue(handlerRes, "saveToDisk", "false");      break;    case FILEACTION_OPEN_CUSTOM:      this._disablePluginForItem(item);      var handlerRes = this._ensureMIMERegistryEntry(item);      this._setLiteralValue(handlerRes, "useSystemDefault", "false");      this._setLiteralValue(handlerRes, "saveToDisk", "false");      var extAppRes = this._getChildResource(handlerRes, "externalApplication");      this._setLiteralValue(extAppRes, "path", item.customHandler.path);      break;    case FILEACTION_SAVE_TO_DISK:      this._disablePluginForItem(item);      var handlerRes = this._ensureMIMERegistryEntry(item);      this._setLiteralValue(handlerRes, "useSystemDefault", "false");      this._setLiteralValue(handlerRes, "saveToDisk", "true");      break;    }        if (this._mimeDS instanceof Components.interfaces.nsIRDFRemoteDataSource)      this._mimeDS.Flush();        // Update the view    this._tree.treeBoxObject.invalidateRow(selection.currentIndex);      },    onSelectionChanged: function ()  {    if (this._tree.view.rowCount == 0)      return;          var selection = this._tree.view.selection;     var selected = selection.count;    this._removeButton.disabled = selected == 0;    this._editButton.disabled = selected != 1;    var stringKey = selected > 1 ? "removeButtonMultiple" : "removeButtonSingle";    this._removeButton.label = this._bundle.getString(stringKey);        var canRemove = true;    var canEdit = true;        var rangeCount = selection.getRangeCount();    var min = { }, max = { };    var setLastSelected = false;    for (var i = 0; i < rangeCount; ++i) {      selection.getRangeAt(i, min, max);            for (var j = min.value; j <= max.value; ++j) {        if (!setLastSelected) {          // Set the last selected index to the first item in the selection          this._tree.setAttribute("lastSelected", j);          setLastSelected = true;        }        var item = this._view.getItemAtIndex(j);        if (item &&             (!item.editable || item.handleMode == FILEACTION_OPEN_INTERNALLY))          canEdit = false;                if (item &&             (!item.editable || item.handleMode == FILEACTION_OPEN_INTERNALLY ||             item.handledOnlyByPlugin))          canRemove = false;      }    }        if (!canRemove)      this._removeButton.disabled = true;    if (!canEdit)      this._editButton.disabled = true;  },    _lastSortProperty : "",  _lastSortAscending: false,  sort: function (aProperty)   {    var ascending = (aProperty == this._lastSortProperty) ? !this._lastSortAscending : true;    function sortByProperty(a, b)     {      return a[aProperty].toLowerCase().localeCompare(b[aProperty].toLowerCase());    }    function sortByExtension(a, b)    {      if (!a.hasExtension && b.hasExtension)        return 1;      if (!b.hasExtension && a.hasExtension)        return -1;      return a.extension.toLowerCase().localeCompare(b.extension.toLowerCase());    }    // Sort the Filtered List, if in Filtered mode    if (!this._view._filtered) {       this._view.activeCollection.sort(aProperty == "extension" ? sortByExtension : sortByProperty);      if (!ascending)        this._view.activeCollection.reverse();    }    this._view.selection.clearSelection();    this._view.selection.select(0);    this._tree.treeBoxObject.invalidate();    this._tree.treeBoxObject.ensureRowIsVisible(0);    this._lastSortAscending = ascending;    this._lastSortProperty = aProperty;  },    clearFilter: function ()  {        // Clear the Filter and the Tree Display    document.getElementById("filter").value = "";    this._view._filtered = false;    this._view._filterSet = [];    // Just reload the list to make sure deletions are respected    this._loadView();    this._updateRowCount(this._updateExclusions());    // Restore selection    this._view.selection.clearSelection();    for (i = 0; i < this._lastSelectedRanges.length; ++i) {      var range = this._lastSelectedRanges[i];      this._view.selection.rangedSelect(range.min, range.max, true);    }    this._lastSelectedRanges = [];    document.getElementById("actionsIntro").value = this._bundle.getString("actionsAll");    document.getElementById("clearFilter").disabled = true;  },    _actionMatchesFilter: function (aAction)  {    return aAction.extension.toLowerCase().indexOf(this._view._filterValue) != -1 ||           aAction.typeName.toLowerCase().indexOf(this._view._filterValue) != -1 ||            aAction.type.toLowerCase().indexOf(this._view._filterValue) != -1 ||           aAction.action.toLowerCase().indexOf(this._view._filterValue) != -1;  },    _filterActions: function (aFilterValue)  {    this._view._filterValue = aFilterValue;    var actions = [];    var collection = this._view._usingExclusionSet ? this._view._exclusionSet : this._actions;    for (var i = 0; i < collection.length; ++i) {      var action = collection[i];      if (this._actionMatchesFilter(action))         actions.push(action);    }    return actions;  },    _lastSelectedRanges: [],  _saveState: function ()  {    // Save selection    var seln = this._view.selection;    this._lastSelectedRanges = [];    var rangeCount = seln.getRangeCount();    for (var i = 0; i < rangeCount; ++i) {      var min = {}; var max = {};      seln.getRangeAt(i, min, max);      this._lastSelectedRanges.push({ min: min.value, max: max.value });    }  },    _filterTimeout: -1,  onFilterInput: function ()  {    if (this._filterTimeout != -1)      clearTimeout(this._filterTimeout);       function filterActions()    {      var filter = document.getElementById("filter").value;      if (filter == "") {        gDownloadActionsWindow.clearFilter();        return;      }              var view = gDownloadActionsWindow._view;      view._filterSet = gDownloadActionsWindow._filterActions(filter);      if (!view._filtered) {        // Save Display Info for the Non-Filtered mode when we first        // enter Filtered mode.         gDownloadActionsWindow._saveState();        view._filtered = true;      }      // Clear the display      gDownloadActionsWindow._updateRowCount(view._filterSet.length);            view.selection.select(0);      document.getElementById("actionsIntro").value = gDownloadActionsWindow._bundle.getString("actionsFiltered");      document.getElementById("clearFilter").disabled = false;    }    window.filterActions = filterActions;    this._filterTimeout = setTimeout("filterActions();", 500);  },    onFilterKeyPress: function (aEvent)  {    if (aEvent.keyCode == 27) // ESC key      this.clearFilter();  },    focusFilterBox: function ()  {     var filter = document.getElementById("filter");    filter.focus();    filter.select();  }  };