The Tor Browser: browser/components/places/content/treeView.js@b8a032363ba2 (annotated)

browser/components/places/content/treeView.js@b8a032363ba2 (annotated)

browser/components/places/content/treeView.js

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* 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/. */
 Components.utils.import('resource://gre/modules/XPCOMUtils.jsm');
 const PTV_interfaces = [Ci.nsITreeView,
                         Ci.nsINavHistoryResultObserver,
                         Ci.nsINavHistoryResultTreeViewer,
                         Ci.nsISupportsWeakReference];
 function PlacesTreeView(aFlatList, aOnOpenFlatContainer, aController) {
   this._tree = null;
   this._result = null;
   this._selection = null;
   this._rootNode = null;
   this._rows = [];
   this._flatList = aFlatList;
   this._openContainerCallback = aOnOpenFlatContainer;
   this._controller = aController;
 }
 PlacesTreeView.prototype = {
   get wrappedJSObject() this,
   __dateService: null,
   get _dateService() {
     if (!this.__dateService) {
       this.__dateService = Cc["@mozilla.org/intl/scriptabledateformat;1"].
                            getService(Ci.nsIScriptableDateFormat);
     }
     return this.__dateService;
   },
   QueryInterface: XPCOMUtils.generateQI(PTV_interfaces),
   // Bug 761494:
   // ----------
   // Some addons use methods from nsINavHistoryResultObserver and
   // nsINavHistoryResultTreeViewer, without QIing to these interfaces first.
   // That's not a problem when the view is retrieved through the
   // <tree>.view getter (which returns the wrappedJSObject of this object),
   // it raises an issue when the view retrieved through the treeBoxObject.view
   // getter.  Thus, to avoid breaking addons, the interfaces are prefetched.
   classInfo: XPCOMUtils.generateCI({ interfaces: PTV_interfaces }),
   /**
    * This is called once both the result and the tree are set.
    */
   _finishInit: function PTV__finishInit() {
     let selection = this.selection;
     if (selection)
       selection.selectEventsSuppressed = true;
     if (!this._rootNode.containerOpen) {
       // This triggers containerStateChanged which then builds the visible
       // section.
       this._rootNode.containerOpen = true;
     }
     else
       this.invalidateContainer(this._rootNode);
     // "Activate" the sorting column and update commands.
     this.sortingChanged(this._result.sortingMode);
     if (selection)
       selection.selectEventsSuppressed = false;
   },
   /**
    * Plain Container: container result nodes which may never include sub
    * hierarchies.
    *
    * When the rows array is constructed, we don't set the children of plain
    * containers.  Instead, we keep placeholders for these children.  We then
    * build these children lazily as the tree asks us for information about each
    * row.  Luckily, the tree doesn't ask about rows outside the visible area.
    *
    * @see _getNodeForRow and _getRowForNode for the actual magic.
    *
    * @note It's guaranteed that all containers are listed in the rows
    * elements array.  It's also guaranteed that separators (if they're not
    * filtered, see below) are listed in the visible elements array, because
    * bookmark folders are never built lazily, as described above.
    *
    * @param aContainer
    *        A container result node.
    *
    * @return true if aContainer is a plain container, false otherwise.
    */
   _isPlainContainer: function PTV__isPlainContainer(aContainer) {
     // Livemarks are always plain containers.
     if (this._controller.hasCachedLivemarkInfo(aContainer))
       return true;
     // We don't know enough about non-query containers.
     if (!(aContainer instanceof Ci.nsINavHistoryQueryResultNode))
       return false;
     switch (aContainer.queryOptions.resultType) {
       case Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_QUERY:
       case Ci.nsINavHistoryQueryOptions.RESULTS_AS_SITE_QUERY:
       case Ci.nsINavHistoryQueryOptions.RESULTS_AS_DATE_SITE_QUERY:
       case Ci.nsINavHistoryQueryOptions.RESULTS_AS_TAG_QUERY:
         return false;
     }
     // If it's a folder, it's not a plain container.
     let nodeType = aContainer.type;
     return nodeType != Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER &&
            nodeType != Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER_SHORTCUT;
   },
   /**
    * Gets the row number for a given node.  Assumes that the given node is
    * visible (i.e. it's not an obsolete node).
    *
    * @param aNode
    *        A result node.  Do not pass an obsolete node, or any
    *        node which isn't supposed to be in the tree (e.g. separators in
    *        sorted trees).
    * @param [optional] aForceBuild
    *        @see _isPlainContainer.
    *        If true, the row will be computed even if the node still isn't set
    *        in our rows array.
    * @param [optional] aParentRow
    *        The row of aNode's parent. Ignored for the root node.
    * @param [optional] aNodeIndex
    *        The index of aNode in its parent.  Only used if aParentRow is
    *        set too.
    *
    * @throws if aNode is invisible.
    * @note If aParentRow and aNodeIndex are passed and parent is a plain
    * container, this method will just return a calculated row value, without
    * making assumptions on existence of the node at that position.
    * @return aNode's row if it's in the rows list or if aForceBuild is set, -1
    *         otherwise.
    */
   _getRowForNode:
   function PTV__getRowForNode(aNode, aForceBuild, aParentRow, aNodeIndex) {
     if (aNode == this._rootNode)
       throw new Error("The root node is never visible");
     // A node is removed form the view either if it has no parent or if its
     // root-ancestor is not the root node (in which case that's the node
     // for which nodeRemoved was called).
     let ancestors = [x for each (x in PlacesUtils.nodeAncestors(aNode))];
     if (ancestors.length == 0 ||
         ancestors[ancestors.length - 1] != this._rootNode) {
       throw new Error("Removed node passed to _getRowForNode");
     }
     // Ensure that the entire chain is open, otherwise that node is invisible.
     for (let ancestor of ancestors) {
       if (!ancestor.containerOpen)
         throw new Error("Invisible node passed to _getRowForNode");
     }
     // Non-plain containers are initially built with their contents.
     let parent = aNode.parent;
     let parentIsPlain = this._isPlainContainer(parent);
     if (!parentIsPlain) {
       if (parent == this._rootNode)
         return this._rows.indexOf(aNode);
       return this._rows.indexOf(aNode, aParentRow);
     }
     let row = -1;
     let useNodeIndex = typeof(aNodeIndex) == "number";
     if (parent == this._rootNode)
       row = useNodeIndex ? aNodeIndex : this._rootNode.getChildIndex(aNode);
     else if (useNodeIndex && typeof(aParentRow) == "number") {
       // If we have both the row of the parent node, and the node's index, we
       // can avoid searching the rows array if the parent is a plain container.
       row = aParentRow + aNodeIndex + 1;
     }
     else {
       // Look for the node in the nodes array.  Start the search at the parent
       // row.  If the parent row isn't passed, we'll pass undefined to indexOf,
       // which is fine.
       row = this._rows.indexOf(aNode, aParentRow);
       if (row == -1 && aForceBuild) {
         let parentRow = typeof(aParentRow) == "number" ? aParentRow
                                                        : this._getRowForNode(parent);
         row = parentRow + parent.getChildIndex(aNode) + 1;
       }
     }
     if (row != -1)
       this._rows[row] = aNode;
     return row;
   },
   /**
    * Given a row, finds and returns the parent details of the associated node.
    *
    * @param aChildRow
    *        Row number.
    * @return [parentNode, parentRow]
    */
   _getParentByChildRow: function PTV__getParentByChildRow(aChildRow) {
     let node = this._getNodeForRow(aChildRow);
     let parent = (node === null) ? this._rootNode : node.parent;
     // The root node is never visible
     if (parent == this._rootNode)
       return [this._rootNode, -1];
     let parentRow = this._rows.lastIndexOf(parent, aChildRow - 1);
     return [parent, parentRow];
   },
   /**
    * Gets the node at a given row.
    */
   _getNodeForRow: function PTV__getNodeForRow(aRow) {
     if (aRow < 0) {
       return null;
     }
     let node = this._rows[aRow];
     if (node !== undefined)
       return node;
     // Find the nearest node.
     let rowNode, row;
     for (let i = aRow - 1; i >= 0 && rowNode === undefined; i--) {
       rowNode = this._rows[i];
       row = i;
     }
     // If there's no container prior to the given row, it's a child of
     // the root node (remember: all containers are listed in the rows array).
     if (!rowNode)
       return this._rows[aRow] = this._rootNode.getChild(aRow);
     // Unset elements may exist only in plain containers.  Thus, if the nearest
     // node is a container, it's the row's parent, otherwise, it's a sibling.
     if (rowNode instanceof Ci.nsINavHistoryContainerResultNode)
       return this._rows[aRow] = rowNode.getChild(aRow - row - 1);
     let [parent, parentRow] = this._getParentByChildRow(row);
     return this._rows[aRow] = parent.getChild(aRow - parentRow - 1);
   },
   /**
    * This takes a container and recursively appends our rows array per its
    * contents.  Assumes that the rows arrays has no rows for the given
    * container.
    *
    * @param [in] aContainer
    *        A container result node.
    * @param [in] aFirstChildRow
    *        The first row at which nodes may be inserted to the row array.
    *        In other words, that's aContainer's row + 1.
    * @param [out] aToOpen
    *        An array of containers to open once the build is done.
    *
    * @return the number of rows which were inserted.
    */
   _buildVisibleSection:
   function PTV__buildVisibleSection(aContainer, aFirstChildRow, aToOpen)
   {
     // There's nothing to do if the container is closed.
     if (!aContainer.containerOpen)
       return 0;
     // Inserting the new elements into the rows array in one shot (by
     // Array.concat) is faster than resizing the array (by splice) on each loop
     // iteration.
     let cc = aContainer.childCount;
     let newElements = new Array(cc);
     this._rows = this._rows.splice(0, aFirstChildRow)
                      .concat(newElements, this._rows);
     if (this._isPlainContainer(aContainer))
       return cc;
     const openLiteral = PlacesUIUtils.RDF.GetResource("http://home.netscape.com/NC-rdf#open");
     const trueLiteral = PlacesUIUtils.RDF.GetLiteral("true");
     let sortingMode = this._result.sortingMode;
     let rowsInserted = 0;
     for (let i = 0; i < cc; i++) {
       let curChild = aContainer.getChild(i);
       let curChildType = curChild.type;
       let row = aFirstChildRow + rowsInserted;
       // Don't display separators when sorted.
       if (curChildType == Ci.nsINavHistoryResultNode.RESULT_TYPE_SEPARATOR) {
         if (sortingMode != Ci.nsINavHistoryQueryOptions.SORT_BY_NONE) {
           // Remove the element for the filtered separator.
           // Notice that the rows array was initially resized to include all
           // children.
           this._rows.splice(row, 1);
           continue;
         }
       }
       this._rows[row] = curChild;
       rowsInserted++;
       // Recursively do containers.
       if (!this._flatList &&
           curChild instanceof Ci.nsINavHistoryContainerResultNode &&
           !this._controller.hasCachedLivemarkInfo(curChild)) {
         let resource = this._getResourceForNode(curChild);
         let isopen = resource != null &&
                      PlacesUIUtils.localStore.HasAssertion(resource,
                                                            openLiteral,
                                                            trueLiteral, true);
         if (isopen != curChild.containerOpen)
           aToOpen.push(curChild);
         else if (curChild.containerOpen && curChild.childCount > 0)
           rowsInserted += this._buildVisibleSection(curChild, row + 1, aToOpen);
       }
     }
     return rowsInserted;
   },
   /**
    * This counts how many rows a node takes in the tree.  For containers it
    * will count the node itself plus any child node following it.
    */
   _countVisibleRowsForNodeAtRow:
   function PTV__countVisibleRowsForNodeAtRow(aNodeRow) {
     let node = this._rows[aNodeRow];
     // If it's not listed yet, we know that it's a leaf node (instanceof also
     // null-checks).
     if (!(node instanceof Ci.nsINavHistoryContainerResultNode))
       return 1;
     let outerLevel = node.indentLevel;
     for (let i = aNodeRow + 1; i < this._rows.length; i++) {
       let rowNode = this._rows[i];
       if (rowNode && rowNode.indentLevel <= outerLevel)
         return i - aNodeRow;
     }
     // This node plus its children take up the bottom of the list.
     return this._rows.length - aNodeRow;
   },
   _getSelectedNodesInRange:
   function PTV__getSelectedNodesInRange(aFirstRow, aLastRow) {
     let selection = this.selection;
     let rc = selection.getRangeCount();
     if (rc == 0)
       return [];
     // The visible-area borders are needed for checking whether a
     // selected row is also visible.
     let firstVisibleRow = this._tree.getFirstVisibleRow();
     let lastVisibleRow = this._tree.getLastVisibleRow();
     let nodesInfo = [];
     for (let rangeIndex = 0; rangeIndex < rc; rangeIndex++) {
       let min = { }, max = { };
       selection.getRangeAt(rangeIndex, min, max);
       // If this range does not overlap the replaced chunk, we don't need to
       // persist the selection.
       if (max.value < aFirstRow || min.value > aLastRow)
         continue;
       let firstRow = Math.max(min.value, aFirstRow);
       let lastRow = Math.min(max.value, aLastRow);
       for (let i = firstRow; i <= lastRow; i++) {
         nodesInfo.push({
           node: this._rows[i],
           oldRow: i,
           wasVisible: i >= firstVisibleRow && i <= lastVisibleRow
         });
       }
     }
     return nodesInfo;
   },
   /**
    * Tries to find an equivalent node for a node which was removed.  We first
    * look for the original node, in case it was just relocated.  Then, if we
    * that node was not found, we look for a node that has the same itemId, uri
    * and time values.
    *
    * @param aUpdatedContainer
    *        An ancestor of the node which was removed.  It does not have to be
    *        its direct parent.
    * @param aOldNode
    *        The node which was removed.
    *
    * @return the row number of an equivalent node for aOldOne, if one was
    *         found, -1 otherwise.
    */
   _getNewRowForRemovedNode:
   function PTV__getNewRowForRemovedNode(aUpdatedContainer, aOldNode) {
     let parent = aOldNode.parent;
     if (parent) {
       // If the node's parent is still set, the node is not obsolete
       // and we should just find out its new position.
       // However, if any of the node's ancestor is closed, the node is
       // invisible.
       let ancestors = PlacesUtils.nodeAncestors(aOldNode);
       for (let ancestor in ancestors) {
         if (!ancestor.containerOpen)
           return -1;
       }
       return this._getRowForNode(aOldNode, true);
     }
     // There's a broken edge case here.
     // If a visit appears in two queries, and the second one was
     // the old node, we'll select the first one after refresh.  There's
     // nothing we could do about that, because aOldNode.parent is
     // gone by the time invalidateContainer is called.
     let newNode = aUpdatedContainer.findNodeByDetails(aOldNode.uri,
                                                       aOldNode.time,
                                                       aOldNode.itemId,
                                                       true);
     if (!newNode)
       return -1;
     return this._getRowForNode(newNode, true);
   },
   /**
    * Restores a given selection state as near as possible to the original
    * selection state.
    *
    * @param aNodesInfo
    *        The persisted selection state as returned by
    *        _getSelectedNodesInRange.
    * @param aUpdatedContainer
    *        The container which was updated.
    */
   _restoreSelection:
   function PTV__restoreSelection(aNodesInfo, aUpdatedContainer) {
     if (aNodesInfo.length == 0)
       return;
     let selection = this.selection;
     // Attempt to ensure that previously-visible selection will be visible
     // if it's re-selected.  However, we can only ensure that for one row.
     let scrollToRow = -1;
     for (let i = 0; i < aNodesInfo.length; i++) {
       let nodeInfo = aNodesInfo[i];
       let row = this._getNewRowForRemovedNode(aUpdatedContainer,
                                               nodeInfo.node);
       // Select the found node, if any.
       if (row != -1) {
         selection.rangedSelect(row, row, true);
         if (nodeInfo.wasVisible && scrollToRow == -1)
           scrollToRow = row;
       }
     }
     // If only one node was previously selected and there's no selection now,
     // select the node at its old row, if any.
     if (aNodesInfo.length == 1 && selection.count == 0) {
       let row = Math.min(aNodesInfo[0].oldRow, this._rows.length - 1);
       if (row != -1) {
         selection.rangedSelect(row, row, true);
         if (aNodesInfo[0].wasVisible && scrollToRow == -1)
           scrollToRow = aNodesInfo[0].oldRow;
       }
     }
     if (scrollToRow != -1)
       this._tree.ensureRowIsVisible(scrollToRow);
   },
   _convertPRTimeToString: function PTV__convertPRTimeToString(aTime) {
     const MS_PER_MINUTE = 60000;
     const MS_PER_DAY = 86400000;
     let timeMs = aTime / 1000; // PRTime is in microseconds
     // Date is calculated starting from midnight, so the modulo with a day are
     // milliseconds from today's midnight.
     // getTimezoneOffset corrects that based on local time, notice midnight
     // can have a different offset during DST-change days.
     let dateObj = new Date();
     let now = dateObj.getTime() - dateObj.getTimezoneOffset() * MS_PER_MINUTE;
     let midnight = now - (now % MS_PER_DAY);
     midnight += new Date(midnight).getTimezoneOffset() * MS_PER_MINUTE;
     let dateFormat = timeMs >= midnight ?
                       Ci.nsIScriptableDateFormat.dateFormatNone :
                       Ci.nsIScriptableDateFormat.dateFormatShort;
     let timeObj = new Date(timeMs);
     return (this._dateService.FormatDateTime("", dateFormat,
       Ci.nsIScriptableDateFormat.timeFormatNoSeconds,
       timeObj.getFullYear(), timeObj.getMonth() + 1,
       timeObj.getDate(), timeObj.getHours(),
       timeObj.getMinutes(), timeObj.getSeconds()));
   },
   COLUMN_TYPE_UNKNOWN: 0,
   COLUMN_TYPE_TITLE: 1,
   COLUMN_TYPE_URI: 2,
   COLUMN_TYPE_DATE: 3,
   COLUMN_TYPE_VISITCOUNT: 4,
   COLUMN_TYPE_KEYWORD: 5,
   COLUMN_TYPE_DESCRIPTION: 6,
   COLUMN_TYPE_DATEADDED: 7,
   COLUMN_TYPE_LASTMODIFIED: 8,
   COLUMN_TYPE_TAGS: 9,
   _getColumnType: function PTV__getColumnType(aColumn) {
     let columnType = aColumn.element.getAttribute("anonid") || aColumn.id;
     switch (columnType) {
       case "title":
         return this.COLUMN_TYPE_TITLE;
       case "url":
         return this.COLUMN_TYPE_URI;
       case "date":
         return this.COLUMN_TYPE_DATE;
       case "visitCount":
         return this.COLUMN_TYPE_VISITCOUNT;
       case "keyword":
         return this.COLUMN_TYPE_KEYWORD;
       case "description":
         return this.COLUMN_TYPE_DESCRIPTION;
       case "dateAdded":
         return this.COLUMN_TYPE_DATEADDED;
       case "lastModified":
         return this.COLUMN_TYPE_LASTMODIFIED;
       case "tags":
         return this.COLUMN_TYPE_TAGS;
     }
     return this.COLUMN_TYPE_UNKNOWN;
   },
   _sortTypeToColumnType: function PTV__sortTypeToColumnType(aSortType) {
     switch (aSortType) {
       case Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_ASCENDING:
         return [this.COLUMN_TYPE_TITLE, false];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_TITLE_DESCENDING:
         return [this.COLUMN_TYPE_TITLE, true];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_ASCENDING:
         return [this.COLUMN_TYPE_DATE, false];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_DATE_DESCENDING:
         return [this.COLUMN_TYPE_DATE, true];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_URI_ASCENDING:
         return [this.COLUMN_TYPE_URI, false];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_URI_DESCENDING:
         return [this.COLUMN_TYPE_URI, true];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_VISITCOUNT_ASCENDING:
         return [this.COLUMN_TYPE_VISITCOUNT, false];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_VISITCOUNT_DESCENDING:
         return [this.COLUMN_TYPE_VISITCOUNT, true];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_KEYWORD_ASCENDING:
         return [this.COLUMN_TYPE_KEYWORD, false];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_KEYWORD_DESCENDING:
         return [this.COLUMN_TYPE_KEYWORD, true];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_ANNOTATION_ASCENDING:
         if (this._result.sortingAnnotation == PlacesUIUtils.DESCRIPTION_ANNO)
           return [this.COLUMN_TYPE_DESCRIPTION, false];
         break;
       case Ci.nsINavHistoryQueryOptions.SORT_BY_ANNOTATION_DESCENDING:
         if (this._result.sortingAnnotation == PlacesUIUtils.DESCRIPTION_ANNO)
           return [this.COLUMN_TYPE_DESCRIPTION, true];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_ASCENDING:
         return [this.COLUMN_TYPE_DATEADDED, false];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_DATEADDED_DESCENDING:
         return [this.COLUMN_TYPE_DATEADDED, true];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_LASTMODIFIED_ASCENDING:
         return [this.COLUMN_TYPE_LASTMODIFIED, false];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_LASTMODIFIED_DESCENDING:
         return [this.COLUMN_TYPE_LASTMODIFIED, true];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_TAGS_ASCENDING:
         return [this.COLUMN_TYPE_TAGS, false];
       case Ci.nsINavHistoryQueryOptions.SORT_BY_TAGS_DESCENDING:
         return [this.COLUMN_TYPE_TAGS, true];
     }
     return [this.COLUMN_TYPE_UNKNOWN, false];
   },
   // nsINavHistoryResultObserver
   nodeInserted: function PTV_nodeInserted(aParentNode, aNode, aNewIndex) {
     NS_ASSERT(this._result, "Got a notification but have no result!");
     if (!this._tree || !this._result)
       return;
     // Bail out for hidden separators.
     if (PlacesUtils.nodeIsSeparator(aNode) && this.isSorted())
       return;
     let parentRow;
     if (aParentNode != this._rootNode) {
       parentRow = this._getRowForNode(aParentNode);
       // Update parent when inserting the first item, since twisty has changed.
       if (aParentNode.childCount == 1)
         this._tree.invalidateRow(parentRow);
     }
     // Compute the new row number of the node.
     let row = -1;
     let cc = aParentNode.childCount;
     if (aNewIndex == 0 || this._isPlainContainer(aParentNode) || cc == 0) {
       // We don't need to worry about sub hierarchies of the parent node
       // if it's a plain container, or if the new node is its first child.
       if (aParentNode == this._rootNode)
         row = aNewIndex;
       else
         row = parentRow + aNewIndex + 1;
     }
     else {
       // Here, we try to find the next visible element in the child list so we
       // can set the new visible index to be right before that.  Note that we
       // have to search down instead of up, because some siblings could have
       // children themselves that would be in the way.
       let separatorsAreHidden = PlacesUtils.nodeIsSeparator(aNode) &&
                                 this.isSorted();
       for (let i = aNewIndex + 1; i < cc; i++) {
         let node = aParentNode.getChild(i);
         if (!separatorsAreHidden || PlacesUtils.nodeIsSeparator(node)) {
           // The children have not been shifted so the next item will have what
           // should be our index.
           row = this._getRowForNode(node, false, parentRow, i);
           break;
         }
       }
       if (row < 0) {
         // At the end of the child list without finding a visible sibling. This
         // is a little harder because we don't know how many rows the last item
         // in our list takes up (it could be a container with many children).
         let prevChild = aParentNode.getChild(aNewIndex - 1);
         let prevIndex = this._getRowForNode(prevChild, false, parentRow,
                                             aNewIndex - 1);
         row = prevIndex + this._countVisibleRowsForNodeAtRow(prevIndex);
       }
     }
     this._rows.splice(row, 0, aNode);
     this._tree.rowCountChanged(row, 1);
     if (PlacesUtils.nodeIsContainer(aNode) &&
         PlacesUtils.asContainer(aNode).containerOpen) {
       this.invalidateContainer(aNode);
     }
   },
   /**
    * THIS FUNCTION DOES NOT HANDLE cases where a collapsed node is being
    * removed but the node it is collapsed with is not being removed (this then
    * just swap out the removee with its collapsing partner). The only time
    * when we really remove things is when deleting URIs, which will apply to
    * all collapsees. This function is called sometimes when resorting items.
    * However, we won't do this when sorted by date because dates will never
    * change for visits, and date sorting is the only time things are collapsed.
    */
   nodeRemoved: function PTV_nodeRemoved(aParentNode, aNode, aOldIndex) {
     NS_ASSERT(this._result, "Got a notification but have no result!");
     if (!this._tree || !this._result)
       return;
     // XXX bug 517701: We don't know what to do when the root node is removed.
     if (aNode == this._rootNode)
       throw Cr.NS_ERROR_NOT_IMPLEMENTED;
     // Bail out for hidden separators.
     if (PlacesUtils.nodeIsSeparator(aNode) && this.isSorted())
       return;
     let parentRow = aParentNode == this._rootNode ?
                     undefined : this._getRowForNode(aParentNode, true);
     let oldRow = this._getRowForNode(aNode, true, parentRow, aOldIndex);
     if (oldRow < 0)
       throw Cr.NS_ERROR_UNEXPECTED;
     // If the node was exclusively selected, the node next to it will be
     // selected.
     let selectNext = false;
     let selection = this.selection;
     if (selection.getRangeCount() == 1) {
       let min = { }, max = { };
       selection.getRangeAt(0, min, max);
       if (min.value == max.value &&
           this.nodeForTreeIndex(min.value) == aNode)
         selectNext = true;
     }
     // Remove the node and its children, if any.
     let count = this._countVisibleRowsForNodeAtRow(oldRow);
     this._rows.splice(oldRow, count);
     this._tree.rowCountChanged(oldRow, -count);
     // Redraw the parent if its twisty state has changed.
     if (aParentNode != this._rootNode && !aParentNode.hasChildren) {
       let parentRow = oldRow - 1;
       this._tree.invalidateRow(parentRow);
     }
     // Restore selection if the node was exclusively selected.
     if (!selectNext)
       return;
     // Restore selection.
     let rowToSelect = Math.min(oldRow, this._rows.length - 1);
     if (rowToSelect != -1)
       this.selection.rangedSelect(rowToSelect, rowToSelect, true);
   },
   nodeMoved:
   function PTV_nodeMoved(aNode, aOldParent, aOldIndex, aNewParent, aNewIndex) {
     NS_ASSERT(this._result, "Got a notification but have no result!");
     if (!this._tree || !this._result)
       return;
     // Bail out for hidden separators.
     if (PlacesUtils.nodeIsSeparator(aNode) && this.isSorted())
       return;
     // Note that at this point the node has already been moved by the backend,
     // so we must give hints to _getRowForNode to get the old row position.
     let oldParentRow = aOldParent == this._rootNode ?
                          undefined : this._getRowForNode(aOldParent, true);
     let oldRow = this._getRowForNode(aNode, true, oldParentRow, aOldIndex);
     if (oldRow < 0)
       throw Cr.NS_ERROR_UNEXPECTED;
     // If this node is a container it could take up more than one row.
     let count = this._countVisibleRowsForNodeAtRow(oldRow);
     // Persist selection state.
     let nodesToReselect =
       this._getSelectedNodesInRange(oldRow, oldRow + count);
     if (nodesToReselect.length > 0)
       this.selection.selectEventsSuppressed = true;
     // Redraw the parent if its twisty state has changed.
     if (aOldParent != this._rootNode && !aOldParent.hasChildren) {
       let parentRow = oldRow - 1;
       this._tree.invalidateRow(parentRow);
     }
     // Remove node and its children, if any, from the old position.
     this._rows.splice(oldRow, count);
     this._tree.rowCountChanged(oldRow, -count);
     // Insert the node into the new position.
     this.nodeInserted(aNewParent, aNode, aNewIndex);
     // Restore selection.
     if (nodesToReselect.length > 0) {
       this._restoreSelection(nodesToReselect, aNewParent);
       this.selection.selectEventsSuppressed = false;
     }
   },
   _invalidateCellValue: function PTV__invalidateCellValue(aNode,
                                                           aColumnType) {
     NS_ASSERT(this._result, "Got a notification but have no result!");
     if (!this._tree || !this._result)
       return;
     // Nothing to do for the root node.
     if (aNode == this._rootNode)
       return;
     let row = this._getRowForNode(aNode);
     if (row == -1)
       return;
     let column = this._findColumnByType(aColumnType);
     if (column && !column.element.hidden)
       this._tree.invalidateCell(row, column);
     // Last modified time is altered for almost all node changes.
     if (aColumnType != this.COLUMN_TYPE_LASTMODIFIED) {
       let lastModifiedColumn =
         this._findColumnByType(this.COLUMN_TYPE_LASTMODIFIED);
       if (lastModifiedColumn && !lastModifiedColumn.hidden)
         this._tree.invalidateCell(row, lastModifiedColumn);
     }
   },
   _populateLivemarkContainer: function PTV__populateLivemarkContainer(aNode) {
     PlacesUtils.livemarks.getLivemark({ id: aNode.itemId })
       .then(aLivemark => {
         let placesNode = aNode;
         // Need to check containerOpen since getLivemark is async.
         if (!placesNode.containerOpen)
           return;
         let children = aLivemark.getNodesForContainer(placesNode);
         for (let i = 0; i < children.length; i++) {
           let child = children[i];
           this.nodeInserted(placesNode, child, i);
         }
       }, Components.utils.reportError);
   },
   nodeTitleChanged: function PTV_nodeTitleChanged(aNode, aNewTitle) {
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_TITLE);
   },
   nodeURIChanged: function PTV_nodeURIChanged(aNode, aNewURI) {
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_URI);
   },
   nodeIconChanged: function PTV_nodeIconChanged(aNode) {
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_TITLE);
   },
   nodeHistoryDetailsChanged:
   function PTV_nodeHistoryDetailsChanged(aNode, aUpdatedVisitDate,
                                          aUpdatedVisitCount) {
     if (aNode.parent && this._controller.hasCachedLivemarkInfo(aNode.parent)) {
       // Find the node in the parent.
       let parentRow = this._flatList ? 0 : this._getRowForNode(aNode.parent);
       for (let i = parentRow; i < this._rows.length; i++) {
         let child = this.nodeForTreeIndex(i);
         if (child.uri == aNode.uri) {
           this._cellProperties.delete(child);
           this._invalidateCellValue(child, this.COLUMN_TYPE_TITLE);
           break;
         }
       }
       return;
     }
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_DATE);
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_VISITCOUNT);
   },
   nodeTagsChanged: function PTV_nodeTagsChanged(aNode) {
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_TAGS);
   },
   nodeKeywordChanged: function PTV_nodeKeywordChanged(aNode, aNewKeyword) {
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_KEYWORD);
   },
   nodeAnnotationChanged: function PTV_nodeAnnotationChanged(aNode, aAnno) {
     if (aAnno == PlacesUIUtils.DESCRIPTION_ANNO) {
       this._invalidateCellValue(aNode, this.COLUMN_TYPE_DESCRIPTION);
     }
     else if (aAnno == PlacesUtils.LMANNO_FEEDURI) {
       PlacesUtils.livemarks.getLivemark({ id: aNode.itemId })
         .then(aLivemark => {
           this._controller.cacheLivemarkInfo(aNode, aLivemark);
           let properties = this._cellProperties.get(aNode);
           this._cellProperties.set(aNode, properties += " livemark ");
           // The livemark attribute is set as a cell property on the title cell.
           this._invalidateCellValue(aNode, this.COLUMN_TYPE_TITLE);
         }, Components.utils.reportError);
     }
   },
   nodeDateAddedChanged: function PTV_nodeDateAddedChanged(aNode, aNewValue) {
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_DATEADDED);
   },
   nodeLastModifiedChanged:
   function PTV_nodeLastModifiedChanged(aNode, aNewValue) {
     this._invalidateCellValue(aNode, this.COLUMN_TYPE_LASTMODIFIED);
   },
   containerStateChanged:
   function PTV_containerStateChanged(aNode, aOldState, aNewState) {
     this.invalidateContainer(aNode);
     if (PlacesUtils.nodeIsFolder(aNode) ||
         (this._flatList && aNode == this._rootNode)) {
       let queryOptions = PlacesUtils.asQuery(this._rootNode).queryOptions;
       if (queryOptions.excludeItems) {
         return;
       }
       PlacesUtils.livemarks.getLivemark({ id: aNode.itemId })
         .then(aLivemark => {
           let shouldInvalidate =
             !this._controller.hasCachedLivemarkInfo(aNode);
           this._controller.cacheLivemarkInfo(aNode, aLivemark);
           if (aNewState == Components.interfaces.nsINavHistoryContainerResultNode.STATE_OPENED) {
             aLivemark.registerForUpdates(aNode, this);
             // Prioritize the current livemark.
             aLivemark.reload();
             PlacesUtils.livemarks.reloadLivemarks();
             if (shouldInvalidate)
               this.invalidateContainer(aNode);
           }
           else {
             aLivemark.unregisterForUpdates(aNode);
           }
         }, () => undefined);
     }
   },
   invalidateContainer: function PTV_invalidateContainer(aContainer) {
     NS_ASSERT(this._result, "Need to have a result to update");
     if (!this._tree)
       return;
     let startReplacement, replaceCount;
     if (aContainer == this._rootNode) {
       startReplacement = 0;
       replaceCount = this._rows.length;
       // If the root node is now closed, the tree is empty.
       if (!this._rootNode.containerOpen) {
         this._rows = [];
         if (replaceCount)
           this._tree.rowCountChanged(startReplacement, -replaceCount);
         return;
       }
     }
     else {
       // Update the twisty state.
       let row = this._getRowForNode(aContainer);
       this._tree.invalidateRow(row);
       // We don't replace the container node itself, so we should decrease the
       // replaceCount by 1.
       startReplacement = row + 1;
       replaceCount = this._countVisibleRowsForNodeAtRow(row) - 1;
     }
     // Persist selection state.
     let nodesToReselect =
       this._getSelectedNodesInRange(startReplacement,
                                     startReplacement + replaceCount);
     // Now update the number of elements.
     this.selection.selectEventsSuppressed = true;
     // First remove the old elements
     this._rows.splice(startReplacement, replaceCount);
     // If the container is now closed, we're done.
     if (!aContainer.containerOpen) {
       let oldSelectionCount = this.selection.count;
       if (replaceCount)
         this._tree.rowCountChanged(startReplacement, -replaceCount);
       // Select the row next to the closed container if any of its
       // children were selected, and nothing else is selected.
       if (nodesToReselect.length > 0 &&
           nodesToReselect.length == oldSelectionCount) {
         this.selection.rangedSelect(startReplacement, startReplacement, true);
         this._tree.ensureRowIsVisible(startReplacement);
       }
       this.selection.selectEventsSuppressed = false;
       return;
     }
     // Otherwise, start a batch first.
     this._tree.beginUpdateBatch();
     if (replaceCount)
       this._tree.rowCountChanged(startReplacement, -replaceCount);
     let toOpenElements = [];
     let elementsAddedCount = this._buildVisibleSection(aContainer,
                                                        startReplacement,
                                                        toOpenElements);
     if (elementsAddedCount)
       this._tree.rowCountChanged(startReplacement, elementsAddedCount);
     if (!this._flatList) {
       // Now, open any containers that were persisted.
       for (let i = 0; i < toOpenElements.length; i++) {
         let item = toOpenElements[i];
         let parent = item.parent;
         // Avoid recursively opening containers.
         while (parent) {
           if (parent.uri == item.uri)
             break;
           parent = parent.parent;
         }
         // If we don't have a parent, we made it all the way to the root
         // and didn't find a match, so we can open our item.
         if (!parent && !item.containerOpen)
           item.containerOpen = true;
       }
     }
     if (this._controller.hasCachedLivemarkInfo(aContainer)) {
       let queryOptions = PlacesUtils.asQuery(this._result.root).queryOptions;
       if (!queryOptions.excludeItems) {
         this._populateLivemarkContainer(aContainer);
       }
     }
     this._tree.endUpdateBatch();
     // Restore selection.
     this._restoreSelection(nodesToReselect, aContainer);
     this.selection.selectEventsSuppressed = false;
   },
   _columns: [],
   _findColumnByType: function PTV__findColumnByType(aColumnType) {
     if (this._columns[aColumnType])
       return this._columns[aColumnType];
     let columns = this._tree.columns;
     let colCount = columns.count;
     for (let i = 0; i < colCount; i++) {
       let column = columns.getColumnAt(i);
       let columnType = this._getColumnType(column);
       this._columns[columnType] = column;
       if (columnType == aColumnType)
         return column;
     }
     // That's completely valid.  Most of our trees actually include just the
     // title column.
     return null;
   },
   sortingChanged: function PTV__sortingChanged(aSortingMode) {
     if (!this._tree || !this._result)
       return;
     // Depending on the sort mode, certain commands may be disabled.
     window.updateCommands("sort");
     let columns = this._tree.columns;
     // Clear old sorting indicator.
     let sortedColumn = columns.getSortedColumn();
     if (sortedColumn)
       sortedColumn.element.removeAttribute("sortDirection");
     // Set new sorting indicator by looking through all columns for ours.
     if (aSortingMode == Ci.nsINavHistoryQueryOptions.SORT_BY_NONE)
       return;
     let [desiredColumn, desiredIsDescending] =
       this._sortTypeToColumnType(aSortingMode);
     let colCount = columns.count;
     let column = this._findColumnByType(desiredColumn);
     if (column) {
       let sortDir = desiredIsDescending ? "descending" : "ascending";
       column.element.setAttribute("sortDirection", sortDir);
     }
   },
   _inBatchMode: false,
   batching: function PTV__batching(aToggleMode) {
     if (this._inBatchMode != aToggleMode) {
       this._inBatchMode = this.selection.selectEventsSuppressed = aToggleMode;
       if (this._inBatchMode) {
         this._tree.beginUpdateBatch();
       }
       else {
         this._tree.endUpdateBatch();
       }
     }
   },
   get result() this._result,
   set result(val) {
     if (this._result) {
       this._result.removeObserver(this);
       this._rootNode.containerOpen = false;
     }
     if (val) {
       this._result = val;
       this._rootNode = this._result.root;
       this._cellProperties = new Map();
       this._cuttingNodes = new Set();
     }
     else if (this._result) {
       delete this._result;
       delete this._rootNode;
       delete this._cellProperties;
       delete this._cuttingNodes;
     }
     // If the tree is not set yet, setTree will call finishInit.
     if (this._tree && val)
       this._finishInit();
     return val;
   },
   nodeForTreeIndex: function PTV_nodeForTreeIndex(aIndex) {
     if (aIndex > this._rows.length)
       throw Cr.NS_ERROR_INVALID_ARG;
     return this._getNodeForRow(aIndex);
   },
   treeIndexForNode: function PTV_treeNodeForIndex(aNode) {
     // The API allows passing invisible nodes.
     try {
       return this._getRowForNode(aNode, true);
     }
     catch(ex) { }
     return Ci.nsINavHistoryResultTreeViewer.INDEX_INVISIBLE;
   },
   _getResourceForNode: function PTV_getResourceForNode(aNode)
   {
     let uri = aNode.uri;
     NS_ASSERT(uri, "if there is no uri, we can't persist the open state");
     return uri ? PlacesUIUtils.RDF.GetResource(uri) : null;
   },
   // nsITreeView
   get rowCount() this._rows.length,
   get selection() this._selection,
   set selection(val) this._selection = val,
   getRowProperties: function() { return ""; },
   getCellProperties:
   function PTV_getCellProperties(aRow, aColumn) {
     // for anonid-trees, we need to add the column-type manually
     var props = "";
     let columnType = aColumn.element.getAttribute("anonid");
     if (columnType)
       props += columnType;
     else
       columnType = aColumn.id;
     // Set the "ltr" property on url cells
     if (columnType == "url")
       props += " ltr";
     if (columnType != "title")
       return props;
     let node = this._getNodeForRow(aRow);
     if (this._cuttingNodes.has(node)) {
       props += " cutting";
     }
     let properties = this._cellProperties.get(node);
     if (properties === undefined) {
       properties = "";
       let itemId = node.itemId;
       let nodeType = node.type;
       if (PlacesUtils.containerTypes.indexOf(nodeType) != -1) {
         if (nodeType == Ci.nsINavHistoryResultNode.RESULT_TYPE_QUERY) {
           properties += " query";
           if (PlacesUtils.nodeIsTagQuery(node))
             properties += " tagContainer";
           else if (PlacesUtils.nodeIsDay(node))
             properties += " dayContainer";
           else if (PlacesUtils.nodeIsHost(node))
             properties += " hostContainer";
         }
         else if (nodeType == Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER ||
                  nodeType == Ci.nsINavHistoryResultNode.RESULT_TYPE_FOLDER_SHORTCUT) {
           if (this._controller.hasCachedLivemarkInfo(node)) {
             properties += " livemark";
           }
           else {
             PlacesUtils.livemarks.getLivemark({ id: node.itemId })
               .then(aLivemark => {
                 this._controller.cacheLivemarkInfo(node, aLivemark);
                 properties += " livemark";
                 // The livemark attribute is set as a cell property on the title cell.
                 this._invalidateCellValue(node, this.COLUMN_TYPE_TITLE);
               }, () => undefined);
           }
         }
         if (itemId != -1) {
           let queryName = PlacesUIUtils.getLeftPaneQueryNameFromId(itemId);
           if (queryName)
             properties += " OrganizerQuery_" + queryName;
         }
       }
       else if (nodeType == Ci.nsINavHistoryResultNode.RESULT_TYPE_SEPARATOR)
         properties += " separator";
       else if (PlacesUtils.nodeIsURI(node)) {
         properties += " " + PlacesUIUtils.guessUrlSchemeForUI(node.uri);
         if (this._controller.hasCachedLivemarkInfo(node.parent)) {
           properties += " livemarkItem";
           if (node.accessCount) {
             properties += " visited";
           }
         }
       }
       this._cellProperties.set(node, properties);
     }
     return props + " " + properties;
   },
   getColumnProperties: function(aColumn) { return ""; },
   isContainer: function PTV_isContainer(aRow) {
     // Only leaf nodes aren't listed in the rows array.
     let node = this._rows[aRow];
     if (node === undefined)
       return false;
     if (PlacesUtils.nodeIsContainer(node)) {
       // Flat-lists may ignore expandQueries and other query options when
       // they are asked to open a container.
       if (this._flatList)
         return true;
       // treat non-expandable childless queries as non-containers
       if (PlacesUtils.nodeIsQuery(node)) {
         let parent = node.parent;
         if ((PlacesUtils.nodeIsQuery(parent) ||
              PlacesUtils.nodeIsFolder(parent)) &&
             !PlacesUtils.asQuery(node).hasChildren)
           return PlacesUtils.asQuery(parent).queryOptions.expandQueries;
       }
       return true;
     }
     return false;
   },
   isContainerOpen: function PTV_isContainerOpen(aRow) {
     if (this._flatList)
       return false;
     // All containers are listed in the rows array.
     return this._rows[aRow].containerOpen;
   },
   isContainerEmpty: function PTV_isContainerEmpty(aRow) {
     if (this._flatList)
       return true;
     let node = this._rows[aRow];
     if (this._controller.hasCachedLivemarkInfo(node)) {
       let queryOptions = PlacesUtils.asQuery(this._result.root).queryOptions;
       return queryOptions.excludeItems;
     }
     // All containers are listed in the rows array.
     return !node.hasChildren;
   },
   isSeparator: function PTV_isSeparator(aRow) {
     // All separators are listed in the rows array.
     let node = this._rows[aRow];
     return node && PlacesUtils.nodeIsSeparator(node);
   },
   isSorted: function PTV_isSorted() {
     return this._result.sortingMode !=
            Ci.nsINavHistoryQueryOptions.SORT_BY_NONE;
   },
   canDrop: function PTV_canDrop(aRow, aOrientation, aDataTransfer) {
     if (!this._result)
       throw Cr.NS_ERROR_UNEXPECTED;
     // Drop position into a sorted treeview would be wrong.
     if (this.isSorted())
       return false;
     let ip = this._getInsertionPoint(aRow, aOrientation);
     return ip && PlacesControllerDragHelper.canDrop(ip, aDataTransfer);
   },
   _getInsertionPoint: function PTV__getInsertionPoint(index, orientation) {
     let container = this._result.root;
     let dropNearItemId = -1;
     // When there's no selection, assume the container is the container
     // the view is populated from (i.e. the result's itemId).
     if (index != -1) {
       let lastSelected = this.nodeForTreeIndex(index);
       if (this.isContainer(index) && orientation == Ci.nsITreeView.DROP_ON) {
         // If the last selected item is an open container, append _into_
         // it, rather than insert adjacent to it.
         container = lastSelected;
         index = -1;
       }
       else if (lastSelected.containerOpen &&
                orientation == Ci.nsITreeView.DROP_AFTER &&
                lastSelected.hasChildren) {
         // If the last selected node is an open container and the user is
         // trying to drag into it as a first node, really insert into it.
         container = lastSelected;
         orientation = Ci.nsITreeView.DROP_ON;
         index = 0;
       }
       else {
         // Use the last-selected node's container.
         container = lastSelected.parent;
         // During its Drag & Drop operation, the tree code closes-and-opens
         // containers very often (part of the XUL "spring-loaded folders"
         // implementation).  And in certain cases, we may reach a closed
         // container here.  However, we can simply bail out when this happens,
         // because we would then be back here in less than a millisecond, when
         // the container had been reopened.
         if (!container || !container.containerOpen)
           return null;
         // Avoid the potentially expensive call to getChildIndex
         // if we know this container doesn't allow insertion.
         if (PlacesControllerDragHelper.disallowInsertion(container))
           return null;
         let queryOptions = PlacesUtils.asQuery(this._result.root).queryOptions;
         if (queryOptions.sortingMode !=
               Ci.nsINavHistoryQueryOptions.SORT_BY_NONE) {
           // If we are within a sorted view, insert at the end.
           index = -1;
         }
         else if (queryOptions.excludeItems ||
                  queryOptions.excludeQueries ||
                  queryOptions.excludeReadOnlyFolders) {
           // Some item may be invisible, insert near last selected one.
           // We don't replace index here to avoid requests to the db,
           // instead it will be calculated later by the controller.
           index = -1;
           dropNearItemId = lastSelected.itemId;
         }
         else {
           let lsi = container.getChildIndex(lastSelected);
           index = orientation == Ci.nsITreeView.DROP_BEFORE ? lsi : lsi + 1;
         }
       }
     }
     if (PlacesControllerDragHelper.disallowInsertion(container))
       return null;
     return new InsertionPoint(PlacesUtils.getConcreteItemId(container),
                               index, orientation,
                               PlacesUtils.nodeIsTagQuery(container),
                               dropNearItemId);
   },
   drop: function PTV_drop(aRow, aOrientation, aDataTransfer) {
     // We are responsible for translating the |index| and |orientation|
     // parameters into a container id and index within the container,
     // since this information is specific to the tree view.
     let ip = this._getInsertionPoint(aRow, aOrientation);
     if (ip)
       PlacesControllerDragHelper.onDrop(ip, aDataTransfer);
     PlacesControllerDragHelper.currentDropTarget = null;
   },
   getParentIndex: function PTV_getParentIndex(aRow) {
     let [parentNode, parentRow] = this._getParentByChildRow(aRow);
     return parentRow;
   },
   hasNextSibling: function PTV_hasNextSibling(aRow, aAfterIndex) {
     if (aRow == this._rows.length - 1) {
       // The last row has no sibling.
       return false;
     }
     let node = this._rows[aRow];
     if (node === undefined || this._isPlainContainer(node.parent)) {
       // The node is a child of a plain container.
       // If the next row is either unset or has the same parent,
       // it's a sibling.
       let nextNode = this._rows[aRow + 1];
       return (nextNode == undefined || nextNode.parent == node.parent);
     }
     let thisLevel = node.indentLevel;
     for (let i = aAfterIndex + 1; i < this._rows.length; ++i) {
       let rowNode = this._getNodeForRow(i);
       let nextLevel = rowNode.indentLevel;
       if (nextLevel == thisLevel)
         return true;
       if (nextLevel < thisLevel)
         break;
     }
     return false;
   },
   getLevel: function(aRow) this._getNodeForRow(aRow).indentLevel,
   getImageSrc: function PTV_getImageSrc(aRow, aColumn) {
     // Only the title column has an image.
     if (this._getColumnType(aColumn) != this.COLUMN_TYPE_TITLE)
       return "";
     return this._getNodeForRow(aRow).icon;
   },
   getProgressMode: function(aRow, aColumn) { },
   getCellValue: function(aRow, aColumn) { },
   getCellText: function PTV_getCellText(aRow, aColumn) {
     let node = this._getNodeForRow(aRow);
     switch (this._getColumnType(aColumn)) {
       case this.COLUMN_TYPE_TITLE:
         // normally, this is just the title, but we don't want empty items in
         // the tree view so return a special string if the title is empty.
         // Do it here so that callers can still get at the 0 length title
         // if they go through the "result" API.
         if (PlacesUtils.nodeIsSeparator(node))
           return "";
         return PlacesUIUtils.getBestTitle(node, true);
       case this.COLUMN_TYPE_TAGS:
         return node.tags;
       case this.COLUMN_TYPE_URI:
         if (PlacesUtils.nodeIsURI(node))
           return node.uri;
         return "";
       case this.COLUMN_TYPE_DATE:
         let nodeTime = node.time;
         if (nodeTime == 0 || !PlacesUtils.nodeIsURI(node)) {
           // hosts and days shouldn't have a value for the date column.
           // Actually, you could argue this point, but looking at the
           // results, seeing the most recently visited date is not what
           // I expect, and gives me no information I know how to use.
           // Only show this for URI-based items.
           return "";
         }
         return this._convertPRTimeToString(nodeTime);
       case this.COLUMN_TYPE_VISITCOUNT:
         return node.accessCount;
       case this.COLUMN_TYPE_KEYWORD:
         if (PlacesUtils.nodeIsBookmark(node))
           return PlacesUtils.bookmarks.getKeywordForBookmark(node.itemId);
         return "";
       case this.COLUMN_TYPE_DESCRIPTION:
         if (node.itemId != -1) {
           try {
             return PlacesUtils.annotations.
                                getItemAnnotation(node.itemId, PlacesUIUtils.DESCRIPTION_ANNO);
           }
           catch (ex) { /* has no description */ }
         }
         return "";
       case this.COLUMN_TYPE_DATEADDED:
         if (node.dateAdded)
           return this._convertPRTimeToString(node.dateAdded);
         return "";
       case this.COLUMN_TYPE_LASTMODIFIED:
         if (node.lastModified)
           return this._convertPRTimeToString(node.lastModified);
         return "";
     }
     return "";
   },
   setTree: function PTV_setTree(aTree) {
     // If we are replacing the tree during a batch, there is a concrete risk
     // that the treeView goes out of sync, thus it's safer to end the batch now.
     // This is a no-op if we are not batching.
     this.batching(false);
     let hasOldTree = this._tree != null;
     this._tree = aTree;
     if (this._result) {
       if (hasOldTree) {
         // detach from result when we are detaching from the tree.
         // This breaks the reference cycle between us and the result.
         if (!aTree) {
           this._result.removeObserver(this);
           this._rootNode.containerOpen = false;
         }
       }
       if (aTree)
         this._finishInit();
     }
   },
   toggleOpenState: function PTV_toggleOpenState(aRow) {
     if (!this._result)
       throw Cr.NS_ERROR_UNEXPECTED;
     let node = this._rows[aRow];
     if (this._flatList && this._openContainerCallback) {
       this._openContainerCallback(node);
       return;
     }
     // Persist containers open status, but never persist livemarks.
     if (!this._controller.hasCachedLivemarkInfo(node)) {
       let resource = this._getResourceForNode(node);
       if (resource) {
         const openLiteral = PlacesUIUtils.RDF.GetResource("http://home.netscape.com/NC-rdf#open");
         const trueLiteral = PlacesUIUtils.RDF.GetLiteral("true");
         if (node.containerOpen)
           PlacesUIUtils.localStore.Unassert(resource, openLiteral, trueLiteral);
         else
           PlacesUIUtils.localStore.Assert(resource, openLiteral, trueLiteral, true);
       }
     }
     node.containerOpen = !node.containerOpen;
   },
   cycleHeader: function PTV_cycleHeader(aColumn) {
     if (!this._result)
       throw Cr.NS_ERROR_UNEXPECTED;
     // Sometimes you want a tri-state sorting, and sometimes you don't. This
     // rule allows tri-state sorting when the root node is a folder. This will
     // catch the most common cases. When you are looking at folders, you want
     // the third state to reset the sorting to the natural bookmark order. When
     // you are looking at history, that third state has no meaning so we try
     // to disallow it.
     //
     // The problem occurs when you have a query that results in bookmark
     // folders. One example of this is the subscriptions view. In these cases,
     // this rule doesn't allow you to sort those sub-folders by their natural
     // order.
     let allowTriState = PlacesUtils.nodeIsFolder(this._result.root);
     let oldSort = this._result.sortingMode;
     let oldSortingAnnotation = this._result.sortingAnnotation;
     let newSort;
     let newSortingAnnotation = "";
     const NHQO = Ci.nsINavHistoryQueryOptions;
     switch (this._getColumnType(aColumn)) {
       case this.COLUMN_TYPE_TITLE:
         if (oldSort == NHQO.SORT_BY_TITLE_ASCENDING)
           newSort = NHQO.SORT_BY_TITLE_DESCENDING;
         else if (allowTriState && oldSort == NHQO.SORT_BY_TITLE_DESCENDING)
           newSort = NHQO.SORT_BY_NONE;
         else
           newSort = NHQO.SORT_BY_TITLE_ASCENDING;
         break;
       case this.COLUMN_TYPE_URI:
         if (oldSort == NHQO.SORT_BY_URI_ASCENDING)
           newSort = NHQO.SORT_BY_URI_DESCENDING;
         else if (allowTriState && oldSort == NHQO.SORT_BY_URI_DESCENDING)
           newSort = NHQO.SORT_BY_NONE;
         else
           newSort = NHQO.SORT_BY_URI_ASCENDING;
         break;
       case this.COLUMN_TYPE_DATE:
         if (oldSort == NHQO.SORT_BY_DATE_ASCENDING)
           newSort = NHQO.SORT_BY_DATE_DESCENDING;
         else if (allowTriState &&
                  oldSort == NHQO.SORT_BY_DATE_DESCENDING)
           newSort = NHQO.SORT_BY_NONE;
         else
           newSort = NHQO.SORT_BY_DATE_ASCENDING;
         break;
       case this.COLUMN_TYPE_VISITCOUNT:
         // visit count default is unusual because we sort by descending
         // by default because you are most likely to be looking for
         // highly visited sites when you click it
         if (oldSort == NHQO.SORT_BY_VISITCOUNT_DESCENDING)
           newSort = NHQO.SORT_BY_VISITCOUNT_ASCENDING;
         else if (allowTriState && oldSort == NHQO.SORT_BY_VISITCOUNT_ASCENDING)
           newSort = NHQO.SORT_BY_NONE;
         else
           newSort = NHQO.SORT_BY_VISITCOUNT_DESCENDING;
         break;
       case this.COLUMN_TYPE_KEYWORD:
         if (oldSort == NHQO.SORT_BY_KEYWORD_ASCENDING)
           newSort = NHQO.SORT_BY_KEYWORD_DESCENDING;
         else if (allowTriState && oldSort == NHQO.SORT_BY_KEYWORD_DESCENDING)
           newSort = NHQO.SORT_BY_NONE;
         else
           newSort = NHQO.SORT_BY_KEYWORD_ASCENDING;
         break;
       case this.COLUMN_TYPE_DESCRIPTION:
         if (oldSort == NHQO.SORT_BY_ANNOTATION_ASCENDING &&
             oldSortingAnnotation == PlacesUIUtils.DESCRIPTION_ANNO) {
           newSort = NHQO.SORT_BY_ANNOTATION_DESCENDING;
           newSortingAnnotation = PlacesUIUtils.DESCRIPTION_ANNO;
         }
         else if (allowTriState &&
                  oldSort == NHQO.SORT_BY_ANNOTATION_DESCENDING &&
                  oldSortingAnnotation == PlacesUIUtils.DESCRIPTION_ANNO)
           newSort = NHQO.SORT_BY_NONE;
         else {
           newSort = NHQO.SORT_BY_ANNOTATION_ASCENDING;
           newSortingAnnotation = PlacesUIUtils.DESCRIPTION_ANNO;
         }
         break;
       case this.COLUMN_TYPE_DATEADDED:
         if (oldSort == NHQO.SORT_BY_DATEADDED_ASCENDING)
           newSort = NHQO.SORT_BY_DATEADDED_DESCENDING;
         else if (allowTriState &&
                  oldSort == NHQO.SORT_BY_DATEADDED_DESCENDING)
           newSort = NHQO.SORT_BY_NONE;
         else
           newSort = NHQO.SORT_BY_DATEADDED_ASCENDING;
         break;
       case this.COLUMN_TYPE_LASTMODIFIED:
         if (oldSort == NHQO.SORT_BY_LASTMODIFIED_ASCENDING)
           newSort = NHQO.SORT_BY_LASTMODIFIED_DESCENDING;
         else if (allowTriState &&
                  oldSort == NHQO.SORT_BY_LASTMODIFIED_DESCENDING)
           newSort = NHQO.SORT_BY_NONE;
         else
           newSort = NHQO.SORT_BY_LASTMODIFIED_ASCENDING;
         break;
       case this.COLUMN_TYPE_TAGS:
         if (oldSort == NHQO.SORT_BY_TAGS_ASCENDING)
           newSort = NHQO.SORT_BY_TAGS_DESCENDING;
         else if (allowTriState && oldSort == NHQO.SORT_BY_TAGS_DESCENDING)
           newSort = NHQO.SORT_BY_NONE;
         else
           newSort = NHQO.SORT_BY_TAGS_ASCENDING;
         break;
       default:
         throw Cr.NS_ERROR_INVALID_ARG;
     }
     this._result.sortingAnnotation = newSortingAnnotation;
     this._result.sortingMode = newSort;
   },
   isEditable: function PTV_isEditable(aRow, aColumn) {
     // At this point we only support editing the title field.
     if (aColumn.index != 0)
       return false;
     // Only bookmark-nodes are editable, and those are never built lazily
     let node = this._rows[aRow];
     if (!node || node.itemId == -1)
       return false;
     // The following items are never editable:
     // * Read-only items.
     // * places-roots
     // * separators
     if (PlacesUtils.nodeIsReadOnly(node) ||
         PlacesUtils.nodeIsSeparator(node))
       return false;
     if (PlacesUtils.nodeIsFolder(node)) {
       let itemId = PlacesUtils.getConcreteItemId(node);
       if (PlacesUtils.isRootItem(itemId))
         return false;
     }
     return true;
   },
   setCellText: function PTV_setCellText(aRow, aColumn, aText) {
     // We may only get here if the cell is editable.
     let node = this._rows[aRow];
     if (node.title != aText) {
       let txn = new PlacesEditItemTitleTransaction(node.itemId, aText);
       PlacesUtils.transactionManager.doTransaction(txn);
     }
   },
   toggleCutNode: function PTV_toggleCutNode(aNode, aValue) {
     let currentVal = this._cuttingNodes.has(aNode);
     if (currentVal != aValue) {
       if (aValue)
         this._cuttingNodes.add(aNode);
       else
         this._cuttingNodes.delete(aNode);
       this._invalidateCellValue(aNode, this.COLUMN_TYPE_TITLE);
     }
   },
   selectionChanged: function() { },
   cycleCell: function(aRow, aColumn) { },
   isSelectable: function(aRow, aColumn) { return false; },
   performAction: function(aAction) { },
   performActionOnRow: function(aAction, aRow) { },
   performActionOnCell: function(aAction, aRow, aColumn) { }
 };