/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Dave Hyatt <hyatt@mozilla.org> (Original Author)
 *   Dean Tessman <dean_tessman@hotmail.com>
 *   Brian Ryner <bryner@brianryner.com>
 *   Jan Varga <varga@ku.sk>
 *   Nate Nielsen <nielsen@memberwebs.com>
 *   Mark Banner <mark@standard8.demon.co.uk>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef nsTreeBodyFrame_h
#define nsTreeBodyFrame_h

#include "nsLeafBoxFrame.h"
#include "nsITreeView.h"
#include "nsICSSPseudoComparator.h"
#include "nsIScrollbarMediator.h"
#include "nsIDragSession.h"
#include "nsITimer.h"
#include "nsIReflowCallback.h"
#include "nsILookAndFeel.h"
#include "nsTArray.h"
#include "nsTreeStyleCache.h"
#include "nsTreeColumns.h"
#include "nsTreeImageListener.h"
#include "nsAutoPtr.h"
#include "nsDataHashtable.h"
#include "imgIRequest.h"
#include "imgIDecoderObserver.h"
#include "nsIScrollbarFrame.h"
#include "nsThreadUtils.h"

class nsOverflowChecker;

// An entry in the tree's image cache
struct nsTreeImageCacheEntry
{
  nsTreeImageCacheEntry() {}
  nsTreeImageCacheEntry(imgIRequest *aRequest, imgIDecoderObserver *aListener)
    : request(aRequest), listener(aListener) {}

  nsCOMPtr<imgIRequest> request;
  nsCOMPtr<imgIDecoderObserver> listener;
};

#define NS_TREEBODYFRAME_IID \
{ 0xe35eb017, 0xa679, 0x4d4d, \
  { 0x83, 0xda, 0xce, 0xd6, 0x20, 0xae, 0x9e, 0x66 } }

// The actual frame that paints the cells and rows.
class NS_FINAL_CLASS nsTreeBodyFrame
  : public nsLeafBoxFrame
  , public nsICSSPseudoComparator
  , public nsIScrollbarMediator
  , public nsIReflowCallback
{
public:
  nsTreeBodyFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
  ~nsTreeBodyFrame();

  NS_DECLARE_STATIC_IID_ACCESSOR(NS_TREEBODYFRAME_IID)

  NS_DECL_ISUPPORTS

  // non-virtual signatures like nsITreeBodyFrame
  nsresult GetColumns(nsITreeColumns **aColumns);
  nsresult GetView(nsITreeView **aView);
  nsresult SetView(nsITreeView *aView);
  nsresult GetFocused(PRBool *aFocused);
  nsresult SetFocused(PRBool aFocused);
  nsresult GetTreeBody(nsIDOMElement **aElement);
  nsresult GetRowHeight(PRInt32 *aValue);
  nsresult GetRowWidth(PRInt32 *aValue);
  nsresult GetHorizontalPosition(PRInt32 *aValue);
  nsresult GetSelectionRegion(nsIScriptableRegion **aRegion);
  nsresult GetFirstVisibleRow(PRInt32 *aValue);
  nsresult GetLastVisibleRow(PRInt32 *aValue);
  nsresult GetPageLength(PRInt32 *aValue);
  nsresult EnsureRowIsVisible(PRInt32 aRow);
  nsresult EnsureCellIsVisible(PRInt32 aRow, nsITreeColumn *aCol);
  nsresult ScrollToRow(PRInt32 aRow);
  nsresult ScrollByLines(PRInt32 aNumLines);
  nsresult ScrollByPages(PRInt32 aNumPages);
  nsresult ScrollToCell(PRInt32 aRow, nsITreeColumn *aCol);
  nsresult ScrollToColumn(nsITreeColumn *aCol);
  nsresult ScrollToHorizontalPosition(PRInt32 aValue);
  nsresult Invalidate();
  nsresult InvalidateColumn(nsITreeColumn *aCol);
  nsresult InvalidateRow(PRInt32 aRow);
  nsresult InvalidateCell(PRInt32 aRow, nsITreeColumn *aCol);
  nsresult InvalidateRange(PRInt32 aStart, PRInt32 aEnd);
  nsresult InvalidateColumnRange(PRInt32 aStart, PRInt32 aEnd,
                                 nsITreeColumn *aCol);
  nsresult GetRowAt(PRInt32 aX, PRInt32 aY, PRInt32 *aValue);
  nsresult GetCellAt(PRInt32 aX, PRInt32 aY, PRInt32 *aRow,
                     nsITreeColumn **aCol, nsACString &aChildElt);
  nsresult GetCoordsForCellItem(PRInt32 aRow, nsITreeColumn *aCol,
                                const nsACString &aElt,
                                PRInt32 *aX, PRInt32 *aY,
                                PRInt32 *aWidth, PRInt32 *aHeight);
  nsresult IsCellCropped(PRInt32 aRow, nsITreeColumn *aCol, PRBool *aResult);
  nsresult RowCountChanged(PRInt32 aIndex, PRInt32 aCount);
  nsresult BeginUpdateBatch();
  nsresult EndUpdateBatch();
  nsresult ClearStyleAndImageCaches();

  // nsIBox
  virtual nsSize GetMinSize(nsBoxLayoutState& aBoxLayoutState);
  virtual void SetBounds(nsBoxLayoutState& aBoxLayoutState, const nsRect& aRect,
                         PRBool aRemoveOverflowArea = PR_FALSE);

  // nsIReflowCallback
  virtual PRBool ReflowFinished();
  virtual void ReflowCallbackCanceled();

  // nsICSSPseudoComparator
  NS_IMETHOD PseudoMatches(nsIAtom* aTag, nsCSSSelector* aSelector, PRBool* aResult);

  // nsIScrollbarMediator
  NS_IMETHOD PositionChanged(nsISupports* aScrollbar, PRInt32 aOldIndex, PRInt32& aNewIndex);
  NS_IMETHOD ScrollbarButtonPressed(nsISupports* aScrollbar, PRInt32 aOldIndex, PRInt32 aNewIndex);
  NS_IMETHOD VisibilityChanged(nsISupports* aScrollbar, PRBool aVisible) { Invalidate(); return NS_OK; }

  // Overridden from nsIFrame to cache our pres context.
  NS_IMETHOD Init(nsIContent*     aContent,
                  nsIFrame*       aParent,
                  nsIFrame*       aPrevInFlow);
  virtual void Destroy();

  NS_IMETHOD GetCursor(const nsPoint& aPoint,
                       nsIFrame::Cursor& aCursor);

  NS_IMETHOD HandleEvent(nsPresContext* aPresContext,
                         nsGUIEvent* aEvent,
                         nsEventStatus* aEventStatus);

  NS_IMETHOD BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                              const nsRect&           aDirtyRect,
                              const nsDisplayListSet& aLists);

  virtual void DidSetStyleContext(nsStyleContext* aOldStyleContext);

  friend nsIFrame* NS_NewTreeBodyFrame(nsIPresShell* aPresShell);
  friend class nsTreeColumn;

  struct ScrollParts {
    nsIScrollbarFrame* mVScrollbar;
    nsIContent*        mVScrollbarContent;
    nsIScrollbarFrame* mHScrollbar;
    nsIContent*        mHScrollbarContent;
    nsIFrame*          mColumnsFrame;
    nsIScrollableView* mColumnsScrollableView;
  };

  void PaintTreeBody(nsIRenderingContext& aRenderingContext,
                     const nsRect& aDirtyRect, nsPoint aPt);

  nsITreeBoxObject* GetTreeBoxObject() const { return mTreeBoxObject; }

protected:
  friend class nsOverflowChecker;

  // This method paints a specific column background of the tree.
  void PaintColumn(nsTreeColumn*        aColumn,
                   const nsRect&        aColumnRect,
                   nsPresContext*      aPresContext,
                   nsIRenderingContext& aRenderingContext,
                   const nsRect&        aDirtyRect);

  // This method paints a single row in the tree.
  void PaintRow(PRInt32              aRowIndex,
                const nsRect&        aRowRect,
                nsPresContext*       aPresContext,
                nsIRenderingContext& aRenderingContext,
                const nsRect&        aDirtyRect,
                nsPoint              aPt);

  // This method paints a single separator in the tree.
  void PaintSeparator(PRInt32              aRowIndex,
                      const nsRect&        aSeparatorRect,
                      nsPresContext*      aPresContext,
                      nsIRenderingContext& aRenderingContext,
                      const nsRect&        aDirtyRect);

  // This method paints a specific cell in a given row of the tree.
  void PaintCell(PRInt32              aRowIndex, 
                 nsTreeColumn*        aColumn,
                 const nsRect&        aCellRect,
                 nsPresContext*       aPresContext,
                 nsIRenderingContext& aRenderingContext,
                 const nsRect&        aDirtyRect,
                 nscoord&             aCurrX,
                 nsPoint              aPt);

  // This method paints the twisty inside a cell in the primary column of an tree.
  void PaintTwisty(PRInt32              aRowIndex,
                   nsTreeColumn*        aColumn,
                   const nsRect&        aTwistyRect,
                   nsPresContext*      aPresContext,
                   nsIRenderingContext& aRenderingContext,
                   const nsRect&        aDirtyRect,
                   nscoord&             aRemainingWidth,
                   nscoord&             aCurrX);

  // This method paints the image inside the cell of an tree.
  void PaintImage(PRInt32              aRowIndex,
                  nsTreeColumn*        aColumn,
                  const nsRect&        aImageRect,
                  nsPresContext*      aPresContext,
                  nsIRenderingContext& aRenderingContext,
                  const nsRect&        aDirtyRect,
                  nscoord&             aRemainingWidth,
                  nscoord&             aCurrX);

  // This method paints the text string inside a particular cell of the tree.
  void PaintText(PRInt32              aRowIndex, 
                 nsTreeColumn*        aColumn,
                 const nsRect&        aTextRect,
                 nsPresContext*      aPresContext,
                 nsIRenderingContext& aRenderingContext,
                 const nsRect&        aDirtyRect,
                 nscoord&             aCurrX,
                 PRBool               aTextRTL);

  // This method paints the checkbox inside a particular cell of the tree.
  void PaintCheckbox(PRInt32              aRowIndex, 
                     nsTreeColumn*        aColumn,
                     const nsRect&        aCheckboxRect,
                     nsPresContext*      aPresContext,
                     nsIRenderingContext& aRenderingContext,
                     const nsRect&        aDirtyRect);

  // This method paints the progress meter inside a particular cell of the tree.
  void PaintProgressMeter(PRInt32              aRowIndex, 
                          nsTreeColumn*        aColumn,
                          const nsRect&        aProgressMeterRect,
                          nsPresContext*      aPresContext,
                          nsIRenderingContext& aRenderingContext,
                          const nsRect&        aDirtyRect);

  // This method paints a drop feedback of the tree.
  void PaintDropFeedback(const nsRect&        aDropFeedbackRect, 
                         nsPresContext*      aPresContext,
                         nsIRenderingContext& aRenderingContext,
                         const nsRect&        aDirtyRect,
                         nsPoint              aPt);

  // This method is called with a specific style context and rect to
  // paint the background rect as if it were a full-blown frame.
  void PaintBackgroundLayer(nsStyleContext*      aStyleContext,
                            nsPresContext*      aPresContext, 
                            nsIRenderingContext& aRenderingContext, 
                            const nsRect&        aRect,
                            const nsRect&        aDirtyRect);


  PRInt32 GetLastVisibleRow() {
    return mTopRowIndex + mPageLength;
  }

  // An internal hit test.  aX and aY are expected to be in twips in the
  // coordinate system of this frame.
  PRInt32 GetRowAt(nscoord aX, nscoord aY);

  // Check for bidi characters in the text, and if there are any, ensure
  // that the prescontext is in bidi mode.
  void CheckTextForBidi(nsAutoString& aText);

  void AdjustForCellText(nsAutoString& aText,
                         PRInt32 aRowIndex,  nsTreeColumn* aColumn,
                         nsIRenderingContext& aRenderingContext,
                         nsRect& aTextRect);

  // A helper used when hit testing.
  nsIAtom* GetItemWithinCellAt(nscoord aX, const nsRect& aCellRect,
                               PRInt32 aRowIndex, nsTreeColumn* aColumn);

  // An internal hit test.  aX and aY are expected to be in twips in the
  // coordinate system of this frame.
  void GetCellAt(nscoord aX, nscoord aY, PRInt32* aRow, nsTreeColumn** aCol,
                 nsIAtom** aChildElt);

  // Retrieve the area for the twisty for a cell.
  nsITheme* GetTwistyRect(PRInt32 aRowIndex,
                          nsTreeColumn* aColumn,
                          nsRect& aImageRect,
                          nsRect& aTwistyRect,
                          nsPresContext* aPresContext,
                          nsIRenderingContext& aRenderingContext,
                          nsStyleContext* aTwistyContext);

  // Fetch an image from the image cache.
  nsresult GetImage(PRInt32 aRowIndex, nsTreeColumn* aCol, PRBool aUseContext,
                    nsStyleContext* aStyleContext, PRBool& aAllowImageRegions, imgIContainer** aResult);

  // Returns the size of a given image.   This size *includes* border and
  // padding.  It does not include margins.
  nsRect GetImageSize(PRInt32 aRowIndex, nsTreeColumn* aCol, PRBool aUseContext, nsStyleContext* aStyleContext);

  // Returns the destination size of the image, not including borders and padding.
  nsSize GetImageDestSize(nsStyleContext* aStyleContext, PRBool useImageRegion, imgIContainer* image);

  // Returns the source rectangle of the image to be displayed.
  nsRect GetImageSourceRect(nsStyleContext* aStyleContext, PRBool useImageRegion, imgIContainer* image);

  // Returns the height of rows in the tree.
  PRInt32 GetRowHeight();

  // Returns our indentation width.
  PRInt32 GetIndentation();

  // Calculates our width/height once border and padding have been removed.
  void CalcInnerBox();

  // Calculate the total width of our scrollable portion
  nscoord CalcHorzWidth(const ScrollParts& aParts);

  // Looks up a style context in the style cache.  On a cache miss we resolve
  // the pseudo-styles passed in and place them into the cache.
  nsStyleContext* GetPseudoStyleContext(nsIAtom* aPseudoElement);

  // Retrieves the scrollbars and scrollview relevant to this treebody. We
  // traverse the frame tree under our base element, in frame order, looking
  // for the first relevant vertical scrollbar, horizontal scrollbar, and
  // scrollable frame (with associated content and scrollable view). These
  // are all volatile and should not be retained.
  ScrollParts GetScrollParts();

  // Update the curpos of the scrollbar.
  void UpdateScrollbars(const ScrollParts& aParts);

  // Update the maxpos of the scrollbar.
  void InvalidateScrollbars(const ScrollParts& aParts);

  // Check overflow and generate events.
  void CheckOverflow(const ScrollParts& aParts);

  // Calls UpdateScrollbars, Invalidate aNeedsFullInvalidation if PR_TRUE,
  // InvalidateScrollbars and finally CheckOverflow.
  // returns PR_TRUE if the frame is still alive after the method call.
  PRBool FullScrollbarsUpdate(PRBool aNeedsFullInvalidation);

  // Use to auto-fill some of the common properties without the view having to do it.
  // Examples include container, open, selected, and focus.
  void PrefillPropertyArray(PRInt32 aRowIndex, nsTreeColumn* aCol);

  // Our internal scroll method, used by all the public scroll methods.
  nsresult ScrollInternal(const ScrollParts& aParts, PRInt32 aRow);
  nsresult ScrollToRowInternal(const ScrollParts& aParts, PRInt32 aRow);
  nsresult ScrollToColumnInternal(const ScrollParts& aParts, nsITreeColumn* aCol);
  nsresult ScrollHorzInternal(const ScrollParts& aParts, PRInt32 aPosition);
  nsresult EnsureRowIsVisibleInternal(const ScrollParts& aParts, PRInt32 aRow);
  
  // Convert client pixels into twips in our coordinate space.
  void AdjustClientCoordsToBoxCoordSpace(PRInt32 aX, PRInt32 aY,
                                         nscoord* aResultX, nscoord* aResultY);

  // Convert a border style into line style.
  nsLineStyle ConvertBorderStyleToLineStyle(PRUint8 aBorderStyle);

  // Cache the box object
  void EnsureBoxObject();

  void EnsureView();

  // Get the base element, <tree> or <select>
  nsIContent* GetBaseElement();

  nsresult GetCellWidth(PRInt32 aRow, nsTreeColumn* aCol,
                        nsIRenderingContext* aRenderingContext,
                        nscoord& aDesiredSize, nscoord& aCurrentSize);
  nscoord CalcMaxRowWidth();

  // Translate the given rect horizontally from tree coordinates into the
  // coordinate system of our nsTreeBodyFrame.  If clip is true, then clip the
  // rect to its intersection with mInnerBox in the horizontal direction.
  // Return whether the result has a nonempty intersection with mInnerBox
  // after projecting both onto the horizontal coordinate axis.
  PRBool OffsetForHorzScroll(nsRect& rect, PRBool clip);

  PRBool CanAutoScroll(PRInt32 aRowIndex);

  // Calc the row and above/below/on status given where the mouse currently is hovering.
  // Also calc if we're in the region in which we want to auto-scroll the tree.
  // A positive value of |aScrollLines| means scroll down, a negative value
  // means scroll up, a zero value means that we aren't in drag scroll region.
  void ComputeDropPosition(nsGUIEvent* aEvent, PRInt32* aRow, PRInt16* aOrient,
                           PRInt16* aScrollLines);

  // Mark ourselves dirty if we're a select widget
  void MarkDirtyIfSelect();

  void InvalidateDropFeedback(PRInt32 aRow, PRInt16 aOrientation) {
    InvalidateRow(aRow);
    if (aOrientation != nsITreeView::DROP_ON)
      InvalidateRow(aRow + aOrientation);
  }

  already_AddRefed<nsTreeColumn> GetColumnImpl(nsITreeColumn* aUnknownCol) {
    if (!aUnknownCol)
      return nsnull;

    nsTreeColumn* col;
    aUnknownCol->QueryInterface(NS_GET_IID(nsTreeColumn), (void**)&col);
    return col;
  }

  // Create a new timer. This method is used to delay various actions like
  // opening/closing folders or tree scrolling.
  // aID is type of the action, aFunc is the function to be called when
  // the timer fires and aType is type of timer - one shot or repeating.
  nsresult CreateTimer(const nsILookAndFeel::nsMetricID aID,
                       nsTimerCallbackFunc aFunc, PRInt32 aType,
                       nsITimer** aTimer);

  static void OpenCallback(nsITimer *aTimer, void *aClosure);

  static void CloseCallback(nsITimer *aTimer, void *aClosure);

  static void LazyScrollCallback(nsITimer *aTimer, void *aClosure);

  static void ScrollCallback(nsITimer *aTimer, void *aClosure);

  class ScrollEvent : public nsRunnable {
  public:
    NS_DECL_NSIRUNNABLE
    ScrollEvent(nsTreeBodyFrame *aInner) : mInner(aInner) {}
    void Revoke() { mInner = nsnull; }
  private:
    nsTreeBodyFrame* mInner;
  };

  void PostScrollEvent();
  void FireScrollEvent();

#ifdef ACCESSIBILITY
  /**
   * Fires 'treeRowCountChanged' event asynchronously. The event supports
   * nsIDOMDataContainerEvent interface that is used to expose the following
   * information structures.
   *
   * @param aIndex  the row index rows are added/removed from
   * @param aCount  the number of added/removed rows (the sign points to
   *                an operation, plus - addition, minus - removing)
   */
  void FireRowCountChangedEvent(PRInt32 aIndex, PRInt32 aCount);

  /**
   * Fires 'treeInvalidated' event asynchronously. The event supports
   * nsIDOMDataContainerEvent interface that is used to expose the information
   * structures described by method arguments.
   *
   * @param aStartRow  the start index of invalidated rows, -1 means that
   *                   columns have been invalidated only
   * @param aEndRow    the end index of invalidated rows, -1 means that columns
   *                   have been invalidated only
   * @param aStartCol  the start invalidated column, nsnull means that only rows
   *                   have been invalidated
   * @param aEndCol    the end invalidated column, nsnull means that rows have
   *                   been invalidated only
   */
  void FireInvalidateEvent(PRInt32 aStartRow, PRInt32 aEndRow,
                           nsITreeColumn *aStartCol, nsITreeColumn *aEndCol);
#endif

protected: // Data Members
  // The cached box object parent.
  nsCOMPtr<nsITreeBoxObject> mTreeBoxObject;

  // Cached column information.
  nsRefPtr<nsTreeColumns> mColumns;

  // The current view for this tree widget.  We get all of our row and cell data
  // from the view.
  nsCOMPtr<nsITreeView> mView;    

  // A cache of all the style contexts we have seen for rows and cells of the tree.  This is a mapping from
  // a list of atoms to a corresponding style context.  This cache stores every combination that
  // occurs in the tree, so for n distinct properties, this cache could have 2 to the n entries
  // (the power set of all row properties).
  nsTreeStyleCache mStyleCache;

  // A hashtable that maps from URLs to image request/listener pairs.  The URL
  // is provided by the view or by the style context. The style context
  // represents a resolved :-moz-tree-cell-image (or twisty) pseudo-element.
  // It maps directly to an imgIRequest.
  nsDataHashtable<nsStringHashKey, nsTreeImageCacheEntry> mImageCache;

  // The index of the first visible row and the # of rows visible onscreen.  
  // The tree only examines onscreen rows, starting from
  // this index and going up to index+pageLength.
  PRInt32 mTopRowIndex;
  PRInt32 mPageLength;

  // The horizontal scroll position
  nscoord mHorzPosition;
  // Our desired horizontal width (the width for which we actually have tree
  // columns).
  nscoord mHorzWidth;
  // The amount by which to adjust the width of the last cell.
  // This depends on whether or not the columnpicker and scrollbars are present.
  nscoord mAdjustWidth;

  // Cached heights and indent info.
  nsRect mInnerBox;
  PRInt32 mRowHeight;
  PRInt32 mIndentation;
  nscoord mStringWidth;

  // A scratch array used when looking up cached style contexts.
  nsCOMPtr<nsISupportsArray> mScratchArray;

  // Whether or not we're currently focused.
  PRPackedBool mFocused;

  // Do we have a fixed number of onscreen rows?
  PRPackedBool mHasFixedRowCount;

  PRPackedBool mVerticalOverflow;
  PRPackedBool mHorizontalOverflow;

  PRPackedBool mReflowCallbackPosted;

  PRInt32 mUpdateBatchNest;

  // Cached row count.
  PRInt32 mRowCount;

  // The row the mouse is hovering over.
  PRInt32 mMouseOverRow;

  class Slots {
    public:
      Slots() {
      }

      ~Slots() {
        if (mTimer)
          mTimer->Cancel();
      }

      friend class nsTreeBodyFrame;

    protected:
      // If the drop is actually allowed here or not.
      PRBool                   mDropAllowed;

      // The row the mouse is hovering over during a drop.
      PRInt32                  mDropRow;

      // Where we want to draw feedback (above/on this row/below) if allowed.
      PRInt16                  mDropOrient;

      // Number of lines to be scrolled.
      PRInt16                  mScrollLines;

      // The drag action that was received for this slot
      PRUint32                 mDragAction;

      nsCOMPtr<nsIDragSession> mDragSession;

      // Timer for opening/closing spring loaded folders or scrolling the tree.
      nsCOMPtr<nsITimer>       mTimer;

      // An array used to keep track of all spring loaded folders.
      nsTArray<PRInt32>        mArray;
  };

  Slots* mSlots;

  nsRevocableEventPtr<ScrollEvent> mScrollEvent;
}; // class nsTreeBodyFrame

NS_DEFINE_STATIC_IID_ACCESSOR(nsTreeBodyFrame, NS_TREEBODYFRAME_IID)

#endif
