libs-gui/Source/NSOutlineView.m

/** <title>NSOutlineView</title>

   <abstract>
   This class is a subclass of NSTableView which provides the user with a way
   to display tree structured data in an outline format.
   It is particularly useful for show hierarchical data such as a
   class inheritance tree or any other set of relationships.
   </abstract>
   
   Copyright (C) 2001 Free Software Foundation, Inc.

   Author:  Gregory John Casamento <greg_casamento@yahoo.com>
   Date: October 2001
   
   This file is part of the GNUstep GUI Library.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; see the file COPYING.LIB.
   If not, see <http://www.gnu.org/licenses/> or write to the 
   Free Software Foundation, 51 Franklin Street, Fifth Floor, 
   Boston, MA 02110-1301, USA.
*/ 

#include <Foundation/NSArray.h>
#include <Foundation/NSEnumerator.h>
#include <Foundation/NSException.h>
#include <Foundation/NSIndexSet.h>
#include <Foundation/NSMapTable.h>
#include <Foundation/NSNotification.h>
#include <Foundation/NSNull.h>
#include <Foundation/NSUserDefaults.h>
#include <Foundation/NSValue.h>

#include "AppKit/NSApplication.h"
#include "AppKit/NSCell.h"
#include "AppKit/NSClipView.h"
#include "AppKit/NSColor.h"
#include "AppKit/NSEvent.h"
#include "AppKit/NSGraphics.h"
#include "AppKit/NSImage.h"
#include "AppKit/NSOutlineView.h"
#include "AppKit/NSScroller.h"
#include "AppKit/NSTableColumn.h"
#include "AppKit/NSTableHeaderView.h"
#include "AppKit/NSText.h"
#include "AppKit/NSTextFieldCell.h"
#include "AppKit/NSWindow.h"

static NSNotificationCenter *nc = nil;
static const int current_version = 1;

int NSOutlineViewDropOnItemIndex = -1;

static int lastVerticalQuarterPosition;
static int lastHorizontalHalfPosition;

static NSRect oldDraggingRect;
static int oldDropRow;
static int oldProposedDropRow;
static int currentDropRow;
static int oldDropLevel;
static int currentDropLevel;


// Cache the arrow images...
static NSImage *collapsed = nil;
static NSImage *expanded  = nil;
static NSImage *unexpandable  = nil;

@interface NSOutlineView (NotificationRequestMethods)
- (void) _postSelectionIsChangingNotification;
- (void) _postSelectionDidChangeNotification;
- (void) _postColumnDidMoveNotificationWithOldIndex: (int) oldIndex
                                           newIndex: (int) newIndex;
// FIXME: There is a method with a similar name.but this is never called
//- (void) _postColumnDidResizeNotification;
- (BOOL) _shouldSelectTableColumn: (NSTableColumn *)tableColumn;
- (BOOL) _shouldSelectRow: (int)rowIndex;
- (BOOL) _shouldSelectionChange;
- (BOOL) _shouldEditTableColumn: (NSTableColumn *)tableColumn
                            row: (int) rowIndex;
- (void) _willDisplayCell: (NSCell*)cell
           forTableColumn: (NSTableColumn *)tb
                      row: (int)index;
- (BOOL) _writeRows: (NSIndexSet *)rows
       toPasteboard: (NSPasteboard *)pboard;
- (BOOL) _isDraggingSource;
- (id) _objectValueForTableColumn: (NSTableColumn *)tb
                              row: (int)index;
- (void) _setObjectValue: (id)value
          forTableColumn: (NSTableColumn *)tb
                     row: (int) index;
- (int) _numRows;
@end

// These methods are private...
@interface NSOutlineView (TableViewInternalPrivate)
- (void) _initOutlineDefaults;
- (void) _autosaveExpandedItems;
- (void) _autoloadExpandedItems;
- (void) _collectItemsStartingWith: (id)startitem
                              into: (NSMutableArray *)allChildren;
- (void) _loadDictionaryStartingWith: (id) startitem
                             atLevel: (int) level;
- (void) _openItem: (id)item;
- (void) _closeItem: (id)item;
- (void) _removeChildren: (id)startitem;
@end

@implementation NSOutlineView

// Initialize the class when it is loaded
+ (void) initialize
{
  if (self == [NSOutlineView class])
    {
      [self setVersion: current_version];
      nc = [NSNotificationCenter defaultCenter];
      collapsed    = [NSImage imageNamed: @"common_outlineCollapsed"];
      expanded     = [NSImage imageNamed: @"common_outlineExpanded"];
      unexpandable = [NSImage imageNamed: @"common_outlineUnexpandable"];
    }
}

// Instance methods

/**
 *  Initalizes the outline view with the given frame.   Invokes
 * the superclass method initWithFrame: as well to initialize the object.
 *
 */
- (id)initWithFrame: (NSRect)frame
{
 self = [super initWithFrame: frame];

 if (self != nil)
   {
     [self _initOutlineDefaults];
     //_outlineTableColumn = nil;
   }

  return self;
}

- (void) dealloc
{
  RELEASE(_items);
  RELEASE(_expandedItems);

  NSFreeMapTable(_itemDict);
  NSFreeMapTable(_levelOfItems);

  if (_autosaveExpandedItems)
    {
      // notify when an item expands...
      [nc removeObserver: self
          name: NSOutlineViewItemDidExpandNotification
          object: self];
      
      // notify when an item collapses...
      [nc removeObserver: self
          name: NSOutlineViewItemDidCollapseNotification
          object: self];
    }

  [super dealloc];
}

/**
 * Causes the outline column, the column containing the expand/collapse gadget, to
 * resize based on the amount of space needed by widest content.
 */
- (BOOL)autoResizesOutlineColumn
{
  return _autoResizesOutlineColumn;
}

/**
 * Causes the outline column, the column containing the expand/collapse gadget, to
 * resize based on the amount of space needed by widest content.
 */
- (BOOL)autosaveExpandedItems
{
  return _autosaveExpandedItems;
}

/**
 * Collapses the given item only.  This is the equivalent of calling 
 * [NSOutlineView-collapseItem:collapseChildren:] with NO.
 */
- (void)collapseItem: (id)item
{
  [self collapseItem: item collapseChildren: NO];
}

/**
 * Collapses the specified item.  If collapseChildren is set to YES, then all of the
 * expandable children of this item all also collapsed in a recursive fashion (i.e.
 * all children, grandchildren and etc).
 */
- (void)collapseItem: (id)item collapseChildren: (BOOL)collapseChildren
{
  const SEL shouldSelector = @selector(outlineView:shouldCollapseItem:);
  BOOL canCollapse = YES;

  if ([_delegate respondsToSelector: shouldSelector])
    {
      canCollapse = [_delegate outlineView: self shouldCollapseItem: item];
    }

  if ([self isExpandable: item] && [self isItemExpanded: item] && canCollapse)
    {
      NSMutableDictionary *infoDict = [NSMutableDictionary dictionary];

      [infoDict setObject: item forKey: @"NSObject"];
      
      // Send out the notification to let observers know that this is about
      // to occur.
      [nc postNotificationName: NSOutlineViewItemWillCollapseNotification
          object: self
          userInfo: infoDict];
      
      // collapse...
      [self _closeItem: item];

      // Send out the notification to let observers know that this has
      // occured.
      [nc postNotificationName: NSOutlineViewItemDidCollapseNotification
          object: self
          userInfo: infoDict];
      
      // recursively find all children and call this method to open them.
      if (collapseChildren) // collapse all
        {
          NSMutableArray *allChildren = nil;
          int numchild = 0;
          int index = 0;
          id sitem = (item == nil) ? (id)[NSNull null] : (id)item;

          allChildren = NSMapGet(_itemDict, sitem);
          numchild = [allChildren count];

          for (index = 0;index < numchild;index++)
            {
              id child = [allChildren objectAtIndex: index];

              if ([self isExpandable: child])
                {
                  [self collapseItem: child collapseChildren: collapseChildren];
                }
            }
        }
      [self noteNumberOfRowsChanged];
      // Should only mark the rect below the closed item for redraw
      [self setNeedsDisplay: YES];
    }
}

/**
 * Expands the given item only.  This is the equivalent of calling 
 * [NSOutlineView-expandItem:expandChildren:] with NO.
 */
- (void)expandItem: (id)item
{
  [self expandItem: item expandChildren: NO];
}

/**
 * Expands the specified item.  If expandChildren is set to YES, then all of the
 * expandable children of this item all also expanded in a recursive fashion (i.e.
 * all children, grandchildren and etc).
 */
- (void)expandItem: (id)item expandChildren: (BOOL)expandChildren
{
  const SEL shouldExpandSelector = @selector(outlineView:shouldExpandItem:);
  BOOL canExpand = YES;

  if ([_delegate respondsToSelector: shouldExpandSelector])
    {
      canExpand = [_delegate outlineView: self shouldExpandItem: item];
    }

  // if the item is expandable
  if ([self isExpandable: item])
    {
      // if it is not already expanded and it can be expanded, then expand
      if (![self isItemExpanded: item] && canExpand)
        {
          NSMutableDictionary *infoDict = [NSMutableDictionary dictionary];

          [infoDict setObject: item forKey: @"NSObject"];
          
          // Send out the notification to let observers know that this is about
          // to occur.
          [nc postNotificationName: NSOutlineViewItemWillExpandNotification
              object: self
              userInfo: infoDict];
          
          // insert the root element, if necessary otherwise insert the
          // actual object.
          [self _openItem: item];
          
          // Send out the notification to let observers know that this has
          // occured.
          [nc postNotificationName: NSOutlineViewItemDidExpandNotification
              object: self
              userInfo: infoDict];
        }

      // recursively find all children and call this method to open them.
      if (expandChildren) // expand all
        {
          NSMutableArray *allChildren = nil;
          int numchild = 0;
          int index = 0;
          id sitem = (item == nil) ? (id)[NSNull null] : (id)item;

          allChildren = NSMapGet(_itemDict, sitem);
          numchild = [allChildren count];

          for (index = 0;index < numchild;index++)
            {
              id child = [allChildren objectAtIndex: index];

              if ([self isExpandable: child])
                {
                  [self expandItem: child expandChildren: expandChildren];
                }
            }
        }
      
      [self noteNumberOfRowsChanged];
      // Should only mark the rect below the expanded item for redraw
      [self setNeedsDisplay: YES];
    }
}

/**
 * Returns whether or not the indentation marker or "knob" is indented
 * along with the content inside the cell.
 */
- (BOOL)indentationMarkerFollowsCell
{
  return _indentationMarkerFollowsCell;
}

/**
 * Returns the amount of indentation, in points, for each level 
 * of the tree represented by the outline view.
 */
- (float)indentationPerLevel
{
  return _indentationPerLevel;
}

/**
 * Returns YES, if the item is able to be expanded, NO otherwise.
 */
- (BOOL)isExpandable: (id)item
{
  return [_dataSource outlineView: self isItemExpandable: item];
}

/**
 * Returns YES if the item is expanded or open, NO otherwise.
 */
- (BOOL)isItemExpanded: (id)item
{
  if (item == nil)
      return YES;

  // Check the array to determine if it is expanded.
  return([_expandedItems containsObject: item]);
}

/**
 * Returns the item at a given row. If no item exists for the given row, 
 * returns nil.
 */
- (id)itemAtRow: (int)row
{
  if ((row >= [_items count]) || (row < 0))
    {
      return nil;
    }
  return [_items objectAtIndex: row];
}

/**
 * Returns the level for a given item.
 */
- (int)levelForItem: (id)item
{
  if (item != nil)
    {
      id object = NSMapGet(_levelOfItems, item);
      return [object intValue];
    }

  return -1;
}

/**
 * Returns the level for the given row.
 */
- (int)levelForRow: (int)row
{
  return [self levelForItem: [self itemAtRow: row]];
}

/**
 * Returns the outline table column.
 */
- (NSTableColumn *)outlineTableColumn
{
  return _outlineTableColumn;
}

/**
 * Causes an item to be reloaded.  This is the equivalent of calling
 * [NSOutlineView-reloadItem:reloadChildren:] with reloadChildren set to NO.
 */
- (void) reloadItem: (id)item
{
  [self reloadItem: item reloadChildren: NO];
}

/**
 * Causes an item and all of it's children to be reloaded if reloadChildren is
 * set to YES, if it's set to NO, then only the item itself is refreshed
 * from the datasource.
 */
- (void)reloadItem: (id)item reloadChildren: (BOOL)reloadChildren
{
  int index;
  id parent;
  BOOL expanded;
  id dsobj = nil;
  id object = (item == nil) ? (id)[NSNull null] : (id)item;
  NSArray *allKeys = NSAllMapTableKeys(_itemDict);
  NSEnumerator *en = [allKeys objectEnumerator];

  expanded = [self isItemExpanded: item];

  // find the parent of the item 
  while ((parent = [en nextObject]))
    {
      NSMutableArray *childArray = NSMapGet(_itemDict, parent);

      if ((index = [childArray indexOfObject: object]) != NSNotFound)
        {
          parent = (parent == [NSNull null]) ? (id)nil :  (id)parent;
          dsobj = [_dataSource outlineView: self
                               child: index
                               ofItem: parent];

          if (dsobj != item)
            {
              [childArray replaceObjectAtIndex: index withObject: dsobj];
              // FIXME We need to correct _items, _itemDict, _levelOfItems, 
              // _expandedItems and _selectedItems
            }
          break;
        }
    }
  
  if (reloadChildren)
    {
      [self _removeChildren: dsobj];
      [self _loadDictionaryStartingWith: dsobj
            atLevel: [self levelForItem: dsobj]];

      if (expanded)
        {
          [self _openItem: dsobj];
          [self noteNumberOfRowsChanged];
        }
    }      
  [self setNeedsDisplay: YES];
}

/**
 * Returns the corresponding row in the outline view for the given item.
 * Returns -1 if item is nil or not found.
 */
- (int) rowForItem: (id)item
{
  int row;
  if (item == nil)
    return -1;

  row = [_items indexOfObject: item];
  return (row == NSNotFound) ? -1 : row;
}

/**
 * When set to YES this causes the outline column, the column containing 
 * the expand/collapse gadget, to resize based on the amount of space 
 * needed by widest content.
 */
- (void) setAutoresizesOutlineColumn: (BOOL)resize
{
  _autoResizesOutlineColumn = resize;
}

/**
 * When set to YES, the outline view will save the state of all expanded or 
 * collapsed items in the view to the users defaults for the application the
 * outline view is running in.
 */
- (void) setAutosaveExpandedItems: (BOOL)flag
{
  if (flag == _autosaveExpandedItems)
    {
      return;
    }

  _autosaveExpandedItems = flag;
  if (flag)
    {
      [self _autoloadExpandedItems];
      // notify when an item expands...
      [nc addObserver: self
          selector: @selector(_autosaveExpandedItems)
          name: NSOutlineViewItemDidExpandNotification
          object: self];

      // notify when an item collapses...
      [nc addObserver: self
          selector: @selector(_autosaveExpandedItems)
          name: NSOutlineViewItemDidCollapseNotification
          object: self];
    }
  else
    {
      // notify when an item expands...
      [nc removeObserver: self
          name: NSOutlineViewItemDidExpandNotification
          object: self];

      // notify when an item collapses...
      [nc removeObserver: self
          name: NSOutlineViewItemDidCollapseNotification
          object: self];
    }
}

/**
 * If set to YES, the indentation marker will follow the content at each level.
 * Otherwise, the indentation marker will remain at the left most position of
 * the view regardless of how many levels in the content is indented.
 */
- (void)setIndentationMarkerFollowsCell: (BOOL)followsCell
{
  _indentationMarkerFollowsCell = followsCell;
}

/**
 * Sets the amount, in points, that each level is to be indented by.
 */
- (void)setIndentationPerLevel: (float)newIndentLevel
{
  _indentationPerLevel = newIndentLevel;
}

/**
 * Sets the outline table column in which to place the indentation marker.
 */
- (void)setOutlineTableColumn: (NSTableColumn *)outlineTableColumn
{
  _outlineTableColumn = outlineTableColumn;
}

/**
 * Returns YES, by default.   Subclasses should override this method if 
 * a different behaviour is required.
 */
- (BOOL)shouldCollapseAutoExpandedItemsForDeposited: (BOOL)deposited
{
  return YES;
}

/**
 * Sets the data source for this outline view. 
 */
- (void) setDataSource: (id)anObject
{
#define CHECK_REQUIRED_METHOD(selector_name) \
  if (anObject && ![anObject respondsToSelector: @selector(selector_name)]) \
    [NSException raise: NSInternalInconsistencyException \
                 format: @"data source does not respond to %@", @#selector_name]

  CHECK_REQUIRED_METHOD(outlineView:child:ofItem:);
  CHECK_REQUIRED_METHOD(outlineView:isItemExpandable:);
  CHECK_REQUIRED_METHOD(outlineView:numberOfChildrenOfItem:);
  CHECK_REQUIRED_METHOD(outlineView:objectValueForTableColumn:byItem:);

  // Is the data source editable?
  _dataSource_editable = [anObject respondsToSelector: 
    @selector(outlineView:setObjectValue:forTableColumn:byItem:)];

  /* We do *not* retain the dataSource, it's like a delegate */
  _dataSource = anObject;
  [self tile];
  [self reloadData];
}

/**
 * Forces a from scratch reload of all data in the outline view. 
 */
- (void) reloadData
{
  // release the old array
  if (_items != nil)
    {
      RELEASE(_items); 
    }

  if (_itemDict != NULL)
    {
      NSFreeMapTable(_itemDict);
    }

  if (_levelOfItems != NULL)
    {
      NSFreeMapTable(_levelOfItems);
    }

  // create a new empty one
  _items = [[NSMutableArray alloc] init]; 
  _itemDict = NSCreateMapTable(NSObjectMapKeyCallBacks,
                               NSObjectMapValueCallBacks,
                               64);
  _levelOfItems = NSCreateMapTable(NSObjectMapKeyCallBacks,
                                   NSObjectMapValueCallBacks,
                                   64);

  // reload all the open items...
  [self _loadDictionaryStartingWith: nil
        atLevel: -1];
  [self _openItem: nil];
  [super reloadData];
}

/**
 * Sets the delegate of the outlineView. 
 */
- (void) setDelegate: (id)anObject
{
  const SEL sel = @selector(outlineView:willDisplayCell:forTableColumn:item:);
 
  if (_delegate)
    [nc removeObserver: _delegate name: nil object: self];
  _delegate = anObject;
  
#define SET_DELEGATE_NOTIFICATION(notif_name) \
  if ([_delegate respondsToSelector: @selector(outlineView##notif_name:)]) \
    [nc addObserver: _delegate \
      selector: @selector(outlineView##notif_name:) \
      name: NSOutlineView##notif_name##Notification object: self]
  
  SET_DELEGATE_NOTIFICATION(ColumnDidMove);
  SET_DELEGATE_NOTIFICATION(ColumnDidResize);
  SET_DELEGATE_NOTIFICATION(SelectionDidChange);
  SET_DELEGATE_NOTIFICATION(SelectionIsChanging);
  SET_DELEGATE_NOTIFICATION(ItemDidExpand);
  SET_DELEGATE_NOTIFICATION(ItemDidCollapse);
  SET_DELEGATE_NOTIFICATION(ItemWillExpand);
  SET_DELEGATE_NOTIFICATION(ItemWillCollapse);

  _del_responds = [_delegate respondsToSelector: sel];
}

- (void) encodeWithCoder: (NSCoder*)aCoder
{
  [super encodeWithCoder: aCoder];
  if ([aCoder allowsKeyedCoding] == NO)
    {
      [aCoder encodeValueOfObjCType: @encode(BOOL)
                                 at: &_autoResizesOutlineColumn];
      [aCoder encodeValueOfObjCType: @encode(BOOL)
                                 at: &_indentationMarkerFollowsCell];
      [aCoder encodeValueOfObjCType: @encode(BOOL)
                                 at: &_autosaveExpandedItems];
      [aCoder encodeValueOfObjCType: @encode(float)
                                 at: &_indentationPerLevel];
      [aCoder encodeConditionalObject: _outlineTableColumn];
    }
}

- (id) initWithCoder: (NSCoder *)aDecoder
{
  // Since we only have one version....
  self = [super initWithCoder: aDecoder];
  if (self == nil)
    return self;

  [self _initOutlineDefaults];
 
  if ([aDecoder allowsKeyedCoding])
    {     
      // init the table column... (this can't be chosen on IB either)...
      if ([_tableColumns count] > 0)
        {
          _outlineTableColumn = [_tableColumns objectAtIndex: 0];
        }
    }
  else
    {
      // overrides outline defaults with archived values 
      [aDecoder decodeValueOfObjCType: @encode(BOOL)
                                   at: &_autoResizesOutlineColumn];
      [aDecoder decodeValueOfObjCType: @encode(BOOL)
                                   at: &_indentationMarkerFollowsCell];
      [aDecoder decodeValueOfObjCType: @encode(BOOL)
                                   at: &_autosaveExpandedItems];
      [aDecoder decodeValueOfObjCType: @encode(float)
                                   at: &_indentationPerLevel];
      _outlineTableColumn = [aDecoder decodeObject];
    }
  return self;
}

- (void) mouseDown: (NSEvent *)theEvent
{
  NSPoint location = [theEvent locationInWindow];

  location = [self convertPoint: location  fromView: nil];
  _clickedRow = [self rowAtPoint: location];
  _clickedColumn = [self columnAtPoint: location];

  if (_clickedRow != -1
      && [_tableColumns objectAtIndex: _clickedColumn] == _outlineTableColumn)
    {
      NSImage *image;
      
      id item = [self itemAtRow:_clickedRow];
      int level = [self levelForRow: _clickedRow];
      int position = 0;
     
      if ([self isItemExpanded: item])
        {
          image = expanded;
        }
      else
        {
          image = collapsed;
        }

      if (_indentationMarkerFollowsCell)
        {
          position = _indentationPerLevel * level;
        }

      position += _columnOrigins[_clickedColumn];

      if ([self isExpandable:item]
          && location.x >= position
                && location.x <= position + [image size].width)
        {
          if (![self isItemExpanded: item])
            {
              [self expandItem: item];
            }
          else
            {
              [self collapseItem: item];
            }
          return;
        }
    }

  [super mouseDown: theEvent];
}  

/* 
 * Drawing 
 */
- (void)drawRow: (int)rowIndex clipRect: (NSRect)aRect
{
  int startingColumn; 
  int endingColumn;
  NSTableColumn *tb;
  NSRect drawingRect;
  NSCell *cell;
  NSCell *imageCell = nil;
  NSRect imageRect;
  int i;
  float x_pos;

  if (_dataSource == nil)
    {
      return;
    }

  /* Using columnAtPoint: here would make it called twice per row per drawn 
     rect - so we avoid it and do it natively */

  if (rowIndex >= _numberOfRows)
    {
      return;
    }

  /* Determine starting column as fast as possible */
  x_pos = NSMinX (aRect);
  i = 0;
  while ((x_pos > _columnOrigins[i]) && (i < _numberOfColumns))
    {
      i++;
    }
  startingColumn = (i - 1);

  if (startingColumn == -1)
    startingColumn = 0;

  /* Determine ending column as fast as possible */
  x_pos = NSMaxX (aRect);
  // Nota Bene: we do *not* reset i
  while ((x_pos > _columnOrigins[i]) && (i < _numberOfColumns))
    {
      i++;
    }
  endingColumn = (i - 1);

  if (endingColumn == -1)
    endingColumn = _numberOfColumns - 1;

  /* Draw the row between startingColumn and endingColumn */
  for (i = startingColumn; i <= endingColumn; i++)
    {
      if (i != _editedColumn || rowIndex != _editedRow)
        {
          id item = [self itemAtRow: rowIndex];

          tb = [_tableColumns objectAtIndex: i];
          cell = [tb dataCellForRow: rowIndex];
          [self _willDisplayCell: cell
                forTableColumn: tb
                row: rowIndex];
          [cell setObjectValue: [_dataSource outlineView: self
                                             objectValueForTableColumn: tb
                                             byItem: item]]; 
          drawingRect = [self frameOfCellAtColumn: i
                              row: rowIndex];

          if (tb == _outlineTableColumn)
            {
              NSImage *image = nil;
              int level = 0;
              float indentationFactor = 0.0;
              // float originalWidth = drawingRect.size.width;

              // display the correct arrow...
              if ([self isItemExpanded: item])
                {
                  image = expanded;
                }
              else
                {
                  image = collapsed;
                }

              if (![self isExpandable: item])
                {
                  image = unexpandable;
                }

              level = [self levelForItem: item];
              indentationFactor = _indentationPerLevel * level;
              imageCell = [[NSCell alloc] initImageCell: image];

              if (_indentationMarkerFollowsCell)
                {
                  imageRect.origin.x = drawingRect.origin.x + indentationFactor;
                  imageRect.origin.y = drawingRect.origin.y;
                }
              else
                {
                  imageRect.origin.x = drawingRect.origin.x;
                  imageRect.origin.y = drawingRect.origin.y;
                }
              
              if ([_delegate respondsToSelector: @selector(outlineView:willDisplayOutlineCell:forTableColumn:item:)])
                {
                  [_delegate outlineView: self
                             willDisplayOutlineCell: imageCell
                             forTableColumn: tb
                             item: item];
                }
              
              /* Do not indent if the delegate set the image to nil. */
              if ([imageCell image])
                {
                  imageRect.size.width = [image size].width;
                  imageRect.size.height = [image size].height;
                  [imageCell drawWithFrame: imageRect inView: self];
                  drawingRect.origin.x
                    += indentationFactor + [image size].width + 5;
                  drawingRect.size.width
                    -= indentationFactor + [image size].width + 5;
                }
              else
                {
                  drawingRect.origin.x += indentationFactor;
                  drawingRect.size.width -= indentationFactor;
                }

              RELEASE(imageCell);
            }

          [cell drawWithFrame: drawingRect inView: self];
        }
    }
}

- (void) drawRect: (NSRect)aRect
{
  int index = 0;

  if (_autoResizesOutlineColumn)
    {
      float widest = 0;
      for (index = 0;index < _numberOfRows; index++)
        {
          float offset = [self levelForRow: index] * 
            [self indentationPerLevel];
          NSRect drawingRect = [self frameOfCellAtColumn: 0
                                     row: index];
          float length = drawingRect.size.width + offset;
          if (widest < length) widest = length;
        }
      // [_outlineTableColumn setWidth: widest];
    }

  [super drawRect: aRect];
}

- (void) setDropItem: (id) item
      dropChildIndex: (int) childIndex
{
  int row = [_items indexOfObject: item];
  id itemAfter;

  if (row == NSNotFound)
    {
      return;
    }

  if (childIndex == NSOutlineViewDropOnItemIndex)
    {
      currentDropRow = row;
      currentDropLevel = NSOutlineViewDropOnItemIndex;
    }
  else
    {
      itemAfter = [_dataSource outlineView: self
                               child: childIndex
                               ofItem: item];
      currentDropRow = [_items indexOfObject: itemAfter];
      currentDropLevel = [self levelForItem: itemAfter];
    }
}

/*
 *  Drag'n'drop support
 */

- (NSDragOperation) draggingEntered: (id <NSDraggingInfo>) sender
{
  //NSLog(@"draggingEntered");
  currentDropRow = -1;
  //  currentDropOperation = -1;
  oldDropRow = -1;
  lastVerticalQuarterPosition = -1;
  oldDraggingRect = NSMakeRect(0.,0., 0., 0.);
  return NSDragOperationCopy;
}

- (void) draggingExited: (id <NSDraggingInfo>) sender
{
  [self setNeedsDisplayInRect: oldDraggingRect];
  [self displayIfNeeded];
}

- (NSDragOperation) draggingUpdated: (id <NSDraggingInfo>) sender
{
  NSPoint p = [sender draggingLocation];
  NSRect newRect;
  int row;
  int verticalQuarterPosition;
  int horizontalHalfPosition;
  int levelBefore;
  int levelAfter;
  int level;
  NSDragOperation dragOperation = [sender draggingSourceOperationMask];
 
  p = [self convertPoint: p fromView: nil];
  verticalQuarterPosition = 
    (p.y - _bounds.origin.y) / _rowHeight * 4.;
  horizontalHalfPosition = 
    (p.x - _bounds.origin.y) / _indentationPerLevel * 2.;


  if ((verticalQuarterPosition - oldProposedDropRow * 4 <= 2) &&
      (verticalQuarterPosition - oldProposedDropRow * 4 >= -3))
    {
      row = oldProposedDropRow;
    }
  else
    {
      row = (verticalQuarterPosition + 2) / 4;
    }

  if (row > _numberOfRows)
    row = _numberOfRows;

  //NSLog(@"horizontalHalfPosition = %d", horizontalHalfPosition);
  
  //NSLog(@"dropRow %d", row);

  if (row == 0)
    {
      levelBefore = 0;
    }
  else
    {
      levelBefore = [self levelForRow: (row - 1)];
    }
  if (row == _numberOfRows)
    {
      levelAfter = 0;
    }
  else
    {
      levelAfter = [self levelForRow: row];
    }

  //NSLog(@"horizontalHalfPosition = %d", horizontalHalfPosition);
  //NSLog(@"level before = %d", levelBefore);
  //NSLog(@"level after = %d", levelAfter);
  
  if (levelBefore < levelAfter)
    levelBefore = levelAfter;

  if ((lastVerticalQuarterPosition != verticalQuarterPosition)
      || (lastHorizontalHalfPosition != horizontalHalfPosition))
    {
      id item;
      int childIndex;

      if (horizontalHalfPosition / 2 < levelAfter)
        horizontalHalfPosition = levelAfter * 2;
      else if (horizontalHalfPosition / 2 > levelBefore)
        horizontalHalfPosition = levelBefore * 2 + 1;
      level = horizontalHalfPosition / 2;


      lastVerticalQuarterPosition = verticalQuarterPosition;
      lastHorizontalHalfPosition = horizontalHalfPosition;
      
      //NSLog(@"horizontalHalfPosition = %d", horizontalHalfPosition);
      //NSLog(@"verticalQuarterPosition = %d", verticalQuarterPosition);
      
      currentDropRow = row;
      currentDropLevel = level;

      {
        int i;
        int j = 0;
        int lvl;
        for (i = row - 1; i >= 0; i--)
          {
            lvl = [self levelForRow: i];
            if (lvl == level - 1)
              {
                break;
              }
            else if (lvl == level)
              {
                j++;
              }
          }
        //NSLog(@"found %d (proposed childIndex = %d)", i, j);
        if (i == -1)
          item = nil;
        else
          item = [self itemAtRow: i];
        
        childIndex = j;
      }


      oldProposedDropRow = currentDropRow;
      if ([_dataSource respondsToSelector: 
                         @selector(outlineView:validateDrop:proposedItem:proposedChildIndex:)])
        {
           dragOperation = [_dataSource outlineView: self
                                        validateDrop: sender
                                        proposedItem: item
                                        proposedChildIndex: childIndex];
        }
      
      if ((currentDropRow != oldDropRow) || (currentDropLevel != oldDropLevel))
        {
          [self lockFocus];
          
          [self setNeedsDisplayInRect: oldDraggingRect];
          [self displayIfNeeded];
          
          [[NSColor darkGrayColor] set];
          
          //NSLog(@"currentDropLevel %d, currentDropRow %d", 
          //currentDropLevel, currentDropRow);
                  
          if (currentDropLevel != NSOutlineViewDropOnItemIndex)
            {
              if (currentDropRow == 0)
                {
                  newRect = NSMakeRect([self visibleRect].origin.x,
                                       currentDropRow * _rowHeight,
                                       [self visibleRect].size.width,
                                       3);
                }
              else if (currentDropRow == _numberOfRows)
                {
                  newRect = NSMakeRect([self visibleRect].origin.x,
                                       currentDropRow * _rowHeight - 2,
                                       [self visibleRect].size.width,
                                       3);
                }
              else
                {
                  newRect = NSMakeRect([self visibleRect].origin.x,
                                       currentDropRow * _rowHeight - 1,
                                       [self visibleRect].size.width,
                                       3);
                }
              newRect.origin.x += currentDropLevel * _indentationPerLevel;
              newRect.size.width -= currentDropLevel * _indentationPerLevel;
              NSRectFill(newRect);
              oldDraggingRect = newRect;

            }
          else
            {
              newRect = [self frameOfCellAtColumn: 0
                              row: currentDropRow];
              newRect.origin.x = _bounds.origin.x;
              newRect.size.width = _bounds.size.width + 2;
              newRect.origin.x -= _intercellSpacing.height / 2;
              newRect.size.height += _intercellSpacing.height;
              oldDraggingRect = newRect;
              oldDraggingRect.origin.y -= 1;
              oldDraggingRect.size.height += 2;

              newRect.size.height -= 1;

              newRect.origin.x += 3;
              newRect.size.width -= 3;
                
              if (_drawsGrid)
                {
                  //newRect.origin.y += 1;
                  //newRect.origin.x += 1;
                  //newRect.size.width -= 2;
                  newRect.size.height += 1;
                }
              else
                {
                }

              newRect.origin.x += currentDropLevel * _indentationPerLevel;
              newRect.size.width -= currentDropLevel * _indentationPerLevel;

              NSFrameRectWithWidth(newRect, 2.0);
              //              NSRectFill(newRect);

              }
          [_window flushWindow];
          
          [self unlockFocus];
          
          oldDropRow = currentDropRow;
          oldDropLevel = currentDropLevel;
        }
    }


  return dragOperation;
}

- (BOOL) performDragOperation: (id<NSDraggingInfo>)sender
{
  if ([_dataSource 
        respondsToSelector: 
          @selector(outlineView:acceptDrop:item:childIndex:)])
    {
      id item;
      int childIndex;

      if (currentDropLevel == NSOutlineViewDropOnItemIndex)
        {
          item = [self itemAtRow: currentDropRow];
          childIndex = currentDropLevel;
        }
      else
        {
          int lvl, i, j = 0;
          
          for (i = currentDropRow - 1; i >= 0; i--)
            {
              lvl = [self levelForRow: i];
              if (lvl == currentDropLevel - 1)
                {
                  break;
                }
              else if (lvl == currentDropLevel)
                {
                  j++;
                }
            }
          if (i == -1)
            item = nil;
          else
            item = [self itemAtRow: i];
          
          childIndex = j;
        }
      
      return [_dataSource 
               outlineView: self
               acceptDrop: sender
               item: item
               childIndex: childIndex];
    }

  return NO;
}

- (BOOL) prepareForDragOperation: (id<NSDraggingInfo>)sender
{
  [self setNeedsDisplayInRect: oldDraggingRect];
  [self displayIfNeeded];

  return YES;
}

// Autosave methods...
- (void) setAutosaveName: (NSString *)name
{
  [super setAutosaveName: name];
  [self _autoloadExpandedItems];
}


- (void) editColumn: (int) columnIndex 
                row: (int) rowIndex 
          withEvent: (NSEvent *) theEvent 
             select: (BOOL) flag
{
  NSText *t;
  NSTableColumn *tb;
  NSRect drawingRect, imageRect;
  unsigned length = 0;
  int level = 0;
  float indentationFactor = 0.0;

  // We refuse to edit cells if the delegate can not accept results 
  // of editing.
  if (_dataSource_editable == NO)
    {
      flag = YES;
    }
  
  [self scrollRowToVisible: rowIndex];
  [self scrollColumnToVisible: columnIndex];

  if (rowIndex < 0 || rowIndex >= _numberOfRows 
      || columnIndex < 0 || columnIndex >= _numberOfColumns)
    {
      [NSException raise: NSInvalidArgumentException
                   format: @"Row/column out of index in edit"];
    }
  
  if (_textObject != nil)
    {
      [self validateEditing];
      [self abortEditing];
    }

  // Now (_textObject == nil)

  t = [_window fieldEditor: YES  forObject: self];

  if ([t superview] != nil)
    {
      if ([t resignFirstResponder] == NO)
        {
          return;
        }
    }
  
  _editedRow = rowIndex;
  _editedColumn = columnIndex;

  // Prepare the cell
  tb = [_tableColumns objectAtIndex: columnIndex];
  // NB: need to be released when no longer used
  _editedCell = [[tb dataCellForRow: rowIndex] copy];

  [_editedCell setEditable: _dataSource_editable];
  [_editedCell setObjectValue: [self _objectValueForTableColumn: tb
                                     row: rowIndex]];

  // We really want the correct background color!
  if ([_editedCell respondsToSelector: @selector(setBackgroundColor:)])
    {
      [(NSTextFieldCell *)_editedCell setBackgroundColor: _backgroundColor];
    }
  else
    {
      [t setBackgroundColor: _backgroundColor];
    }
  
  // But of course the delegate can mess it up if it wants
  [self _willDisplayCell: _editedCell
        forTableColumn: tb
        row: rowIndex];

  /* Please note the important point - calling stringValue normally
     causes the _editedCell to call the validateEditing method of its
     control view ... which happens to be this object :-)
     but we don't want any spurious validateEditing to be performed
     before the actual editing is started (otherwise you easily end up
     with the table view picking up the string stored in the field
     editor, which is likely to be the string resulting from the last
     edit somewhere else ... getting into the bug that when you TAB
     from one cell to another one, the string is copied!), so we must
     call stringValue when _textObject is still nil.  */
  if (flag)
    {
      length = [[_editedCell stringValue] length];
    }

  _textObject = [_editedCell setUpFieldEditorAttributes: t];

  drawingRect = [self frameOfCellAtColumn: columnIndex  row: rowIndex];

  if (tb == [self outlineTableColumn])
    {
      id item = nil;
      NSImage *image = nil;
      NSCell *imageCell = nil;

      item = [self itemAtRow: _editedRow];
      // determine which image to use...
      if ([self isItemExpanded: item])
        {
          image = expanded;
        }
      else
        {
          image = collapsed;
        }

      if (![self isExpandable: item])
        {
          image = unexpandable;
        }

      level = [self levelForItem: item];
      indentationFactor = _indentationPerLevel * level;

      // create the image cell..
      imageCell = [[NSCell alloc] initImageCell: image];
      if (_indentationMarkerFollowsCell)
        {
          imageRect.origin.x = drawingRect.origin.x + indentationFactor;
          imageRect.origin.y = drawingRect.origin.y;
        }
      else
        {
          imageRect.origin.x = drawingRect.origin.x;
          imageRect.origin.y = drawingRect.origin.y;
        }
      
      imageRect.size.width = [image size].width;
      imageRect.size.height = [image size].height;

      // draw...
      [self lockFocus];
      [imageCell drawWithFrame: imageRect inView: self];
      [self unlockFocus];

      // move the drawing rect over like in the drawRow routine...
      drawingRect.origin.x += indentationFactor + 5 + [image size].width;
      drawingRect.size.width -= indentationFactor + 5 + [image size].width;

      RELEASE(imageCell);
    }

  if (flag)
    {
      [_editedCell selectWithFrame: drawingRect
                   inView: self
                   editor: _textObject
                   delegate: self
                   start: 0
                   length: length];
    }
  else
    {
      [_editedCell editWithFrame: drawingRect
                   inView: self
                   editor: _textObject
                   delegate: self
                   event: theEvent];
    }

  return;
}

@end /* implementation of NSOutlineView */

@implementation NSOutlineView (NotificationRequestMethods)
/*
 * (NotificationRequestMethods)
 */
- (void) _postSelectionIsChangingNotification
{
  [nc postNotificationName: 
        NSOutlineViewSelectionIsChangingNotification
      object: self];
}
- (void) _postSelectionDidChangeNotification
{
  [nc postNotificationName: 
        NSOutlineViewSelectionDidChangeNotification
      object: self];
}
- (void) _postColumnDidMoveNotificationWithOldIndex: (int) oldIndex
                                           newIndex: (int) newIndex
{
  [nc postNotificationName: 
        NSOutlineViewColumnDidMoveNotification
      object: self
      userInfo: [NSDictionary 
                  dictionaryWithObjectsAndKeys:
                  [NSNumber numberWithInt: newIndex],
                  @"NSNewColumn",
                    [NSNumber numberWithInt: oldIndex],
                  @"NSOldColumn",
                  nil]];
}

- (void) _postColumnDidResizeNotificationWithOldWidth: (float) oldWidth
{
  [nc postNotificationName: 
        NSOutlineViewColumnDidResizeNotification
      object: self
      userInfo: [NSDictionary 
                  dictionaryWithObjectsAndKeys:
                    [NSNumber numberWithFloat: oldWidth],
                  @"NSOldWidth", 
                  nil]];
}

- (BOOL) _shouldSelectTableColumn: (NSTableColumn *)tableColumn
{
  if ([_delegate respondsToSelector: 
    @selector (outlineView:shouldSelectTableColumn:)] == YES) 
    {
      if ([_delegate outlineView: self  shouldSelectTableColumn: tableColumn]
        == NO)
        {
          return NO;
        }
    }

  return YES;
}

- (BOOL) _shouldSelectRow: (int)rowIndex
{
  id item = [self itemAtRow: rowIndex];

  if ([_delegate respondsToSelector: 
    @selector (outlineView:shouldSelectItem:)] == YES) 
    {
      if ([_delegate outlineView: self  shouldSelectItem: item] == NO)
        {
          return NO;
        }
    }
  
  return YES;
}

- (BOOL) _shouldSelectionChange
{
  if ([_delegate respondsToSelector: 
    @selector (selectionShouldChangeInTableView:)] == YES) 
    {
      if ([_delegate selectionShouldChangeInTableView: self] == NO)
        {
          return NO;
        }
    }
  
  return YES;
}

- (BOOL) _shouldEditTableColumn: (NSTableColumn *)tableColumn
                            row: (int) rowIndex
{
  if ([_delegate respondsToSelector: 
    @selector(outlineView:shouldEditTableColumn:item:)])
    {
      id item = [self itemAtRow: rowIndex];

      if ([_delegate outlineView: self shouldEditTableColumn: tableColumn
                     item: item] == NO)
        {
          return NO;
        }
    }

  return YES;
}

- (void) _willDisplayCell: (NSCell*)cell
           forTableColumn: (NSTableColumn *)tb
                      row: (int)index
{
  if (_del_responds)
    {
      id item = [self itemAtRow: index];
  
      [_delegate outlineView: self   
                 willDisplayCell: cell 
                 forTableColumn: tb   
                 item: item];
    }    
}

- (BOOL) _writeRows: (NSIndexSet *)rows
       toPasteboard: (NSPasteboard *)pboard
{
  int count = [rows count];
  NSMutableArray *itemArray = [NSMutableArray arrayWithCapacity: count];
  unsigned int index = [rows firstIndex];
      
  while (index != NSNotFound)
    {
      [itemArray addObject: [self itemAtRow: index]];
      index = [rows indexGreaterThanIndex: index];
    }  

  if ([_dataSource respondsToSelector:
                     @selector(outlineView:writeItems:toPasteboard:)] == YES)
    {
      return [_dataSource outlineView: self
                          writeItems: itemArray
                          toPasteboard: pboard];
    }
  return NO;
}

- (BOOL) _isDraggingSource
{
  return [_dataSource respondsToSelector:
                        @selector(outlineView:writeItems:toPasteboard:)];
}

- (id) _objectValueForTableColumn: (NSTableColumn *)tb
                              row: (int) index
{
  id result = nil;

  if ([_dataSource respondsToSelector:
    @selector(outlineView:objectValueForTableColumn:byItem:)])
    {
      id item = [self itemAtRow: index];

      result = [_dataSource outlineView: self
                            objectValueForTableColumn: tb
                            byItem: item];
    }

  return result;
}

- (void) _setObjectValue: (id)value
          forTableColumn: (NSTableColumn *)tb
                     row: (int) index
{
  if ([_dataSource respondsToSelector:
    @selector(outlineView:setObjectValue:forTableColumn:byItem:)])
    {
      id item = [self itemAtRow: index];

      [_dataSource outlineView: self
                   setObjectValue: value
                   forTableColumn: tb
                   byItem: item];
    }
}

- (int) _numRows
{
  return [_items count];
}

@end

@implementation NSOutlineView (TableViewInternalPrivate)

- (void) _initOutlineDefaults
{
  _itemDict = NSCreateMapTable(NSObjectMapKeyCallBacks,
                               NSObjectMapValueCallBacks,
                               64);
  _items = [[NSMutableArray alloc] init];
  _expandedItems = [[NSMutableArray alloc] init];
  _levelOfItems = NSCreateMapTable(NSObjectMapKeyCallBacks,
                                   NSObjectMapValueCallBacks,
                                   64);

  _indentationMarkerFollowsCell = YES;
  _autoResizesOutlineColumn = NO;
  _autosaveExpandedItems = NO;
  _indentationPerLevel = 10.0;
}

- (void) _autosaveExpandedItems
{
  if (_autosaveExpandedItems && _autosaveName != nil) 
    {
      NSUserDefaults *defaults;
      NSString       *tableKey;

      defaults  = [NSUserDefaults standardUserDefaults];
      tableKey = [NSString stringWithFormat: @"NSOutlineView Expanded Items %@", 
                           _autosaveName];
      [defaults setObject: _expandedItems  forKey: tableKey];
      [defaults synchronize];
    }
}

- (void) _autoloadExpandedItems
{
  if (_autosaveExpandedItems && _autosaveName != nil) 
    { 
      NSUserDefaults *defaults;
      id             config;
      NSString       *tableKey;

      defaults  = [NSUserDefaults standardUserDefaults];
      tableKey = [NSString stringWithFormat: @"NSOutlineView Expanded Items %@",
        _autosaveName];
      config = [defaults objectForKey: tableKey];
      if (config != nil) 
        {
          NSEnumerator *en = [config objectEnumerator];
          id item = nil;
          
          while ((item = [en nextObject]) != nil) 
            {
              [self expandItem: item];
            }
        }
    }
}

// Collect all of the items under a given element.
- (void)_collectItemsStartingWith: (id)startitem
                             into: (NSMutableArray *)allChildren
{
  int num;
  int i;
  id sitem = (startitem == nil) ? (id)[NSNull null] : (id)startitem;
  NSMutableArray *anarray;

  anarray = NSMapGet(_itemDict, sitem); 
  num = [anarray count];
  for (i = 0; i < num; i++)
    {
      id anitem = [anarray objectAtIndex: i];

      // Only collect the children if the item is expanded
      if ([self isItemExpanded: startitem])
        {
          [allChildren addObject: anitem];
        }

      [self _collectItemsStartingWith: anitem
            into: allChildren];
    }
}

- (void) _loadDictionaryStartingWith: (id) startitem
                             atLevel: (int) level
{
  int num = 0; 
  int i = 0;
  id sitem = (startitem == nil) ? (id)[NSNull null] : (id)startitem;
  NSMutableArray *anarray = nil;

  // Check to see if item is expandable before getting the number of
  // items.
  if([_dataSource outlineView: self isItemExpandable: startitem])
    {
      num = [_dataSource outlineView: self
			 numberOfChildrenOfItem: startitem];
    }

  if (num > 0)
    {
      anarray = [NSMutableArray array];
      NSMapInsert(_itemDict, sitem, anarray);
    }

  NSMapInsert(_levelOfItems, sitem, [NSNumber numberWithInt: level]);

  for (i = 0; i < num; i++)
    {
      id anitem = [_dataSource outlineView: self
                               child: i
                               ofItem: startitem];
      
      [anarray addObject: anitem];
      [self _loadDictionaryStartingWith: anitem
            atLevel: level + 1]; 
    }
}

- (void)_closeItem: (id)item
{
  int numchildren = 0;
  int i = 0;
  NSMutableArray *removeAll = [NSMutableArray array];

  [self _collectItemsStartingWith: item into: removeAll];
  numchildren = [removeAll count];

  // close the item...
  if (item != nil)
    {
      [_expandedItems removeObject: item];
    }

  // For the close method it doesn't matter what order they are 
  // removed in.
  for (i=0; i < numchildren; i++)
    {
      id child = [removeAll objectAtIndex: i];
      [_items removeObject: child];
    }
}

- (void)_openItem: (id)item
{
  int numchildren = 0;
  int i = 0;
  int insertionPoint = 0;
  id object = nil;
  id sitem = (item == nil) ? (id)[NSNull null] : (id)item;

  object = NSMapGet(_itemDict, sitem);
  numchildren = [object count];
  
  // open the item...
  if (item != nil)
    {
      [_expandedItems addObject: item];
    }

  insertionPoint = [_items indexOfObject: item];
  if (insertionPoint == NSNotFound)
    {
      insertionPoint = 0;
    }
  else
    {
      insertionPoint++;
    }

  for (i=numchildren-1; i >= 0; i--)
    {
      id obj = NSMapGet(_itemDict, sitem);
      id child = [obj objectAtIndex: i];

      // Add all of the children...
      if ([self isItemExpanded: child])
        {
          NSMutableArray *insertAll = [NSMutableArray array];
          int i = 0, numitems = 0;

          [self _collectItemsStartingWith: child into: insertAll];
          numitems = [insertAll count];
           for (i = numitems-1; i >= 0; i--)
            {
              [_items insertObject: [insertAll objectAtIndex: i]
                      atIndex: insertionPoint];
            }
        }
      
      // Add the parent
      [_items insertObject: child atIndex: insertionPoint];
    }
}

- (void) _removeChildren: (id)startitem
{
  int numchildren = 0;
  int i = 0;
  id sitem = (startitem == nil) ? (id)[NSNull null] : (id)startitem;
  NSMutableArray *anarray;
  
  anarray = NSMapGet(_itemDict, sitem); 
  numchildren = [anarray count];
  for (i = 0; i < numchildren; i++)
    {
      id child = [anarray objectAtIndex: i];

      [self _removeChildren: child];
      NSMapRemove(_itemDict, child); 
      [_items removeObject: child];
      [_expandedItems removeObject: child];
    }
  [anarray removeAllObjects];
}

@end