|
//---------------------------------------------------------------------------
//
// <copyright file=TextTreeObjectNode.cs company=Microsoft>
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
//
// Description: A TextContainer node representing a UIElement.
//
// History:
// 02/18/2004 : Microsoft - Created
//
//---------------------------------------------------------------------------
using System;
using MS.Internal;
namespace System.Windows.Documents
{
// UIElements in the TextContainer are represented internally by TextTreeObjectNodes.
//
// This class is a simple container for a UIElement, it only holds state.
internal class TextTreeObjectNode : TextTreeNode
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
// Creates a new TextTreeObjectNode instance.
internal TextTreeObjectNode(DependencyObject embeddedElement)
{
_embeddedElement = embeddedElement;
_symbolOffsetCache = -1;
}
#endregion Constructors
//------------------------------------------------------
//
// Public Methods
//
//------------------------------------------------------
#region Public Methods
#if DEBUG
// Debug-only ToString override.
public override string ToString()
{
return ("ObjectNode Id=" + this.DebugId + " Object=" + _embeddedElement);
}
#endif // DEBUG
#endregion Public Methods
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
#region Internal Methods
// Returns a shallow copy of this node.
internal override TextTreeNode Clone()
{
TextTreeObjectNode clone;
clone = new TextTreeObjectNode(_embeddedElement);
return clone;
}
// Returns the TextPointerContext of the node.
internal override TextPointerContext GetPointerContext(LogicalDirection direction)
{
return TextPointerContext.EmbeddedElement;
}
#endregion Internal methods
//------------------------------------------------------
//
// Internal Properties
//
//------------------------------------------------------
#region Internal Properties
// If this node is a local root, then ParentNode contains it.
// Otherwise, this is the node parenting this node within its tree.
internal override SplayTreeNode ParentNode
{
get
{
return _parentNode;
}
set
{
_parentNode = (TextTreeNode)value;
}
}
// TextTreeObjectNode never has contained nodes.
internal override SplayTreeNode ContainedNode
{
get
{
return null;
}
set
{
Invariant.Assert(false, "Can't set contained node on a TextTreeObjectNode!");
}
}
// Count of symbols of all siblings preceding this node.
internal override int LeftSymbolCount
{
get
{
return _leftSymbolCount;
}
set
{
_leftSymbolCount = value;
}
}
// Count of symbols of all siblings preceding this node.
internal override int LeftCharCount
{
get
{
return _leftCharCount;
}
set
{
_leftCharCount = value;
}
}
// Left child node in a sibling tree.
internal override SplayTreeNode LeftChildNode
{
get
{
return _leftChildNode;
}
set
{
_leftChildNode = (TextTreeNode)value;
}
}
// Right child node in a sibling tree.
internal override SplayTreeNode RightChildNode
{
get
{
return _rightChildNode;
}
set
{
_rightChildNode = (TextTreeNode)value;
}
}
// The TextContainer's generation when SymbolOffsetCache was last updated.
// If the current generation doesn't match TextContainer.Generation, then
// SymbolOffsetCache is invalid.
internal override uint Generation
{
get
{
return _generation;
}
set
{
_generation = value;
}
}
// Cached symbol offset.
internal override int SymbolOffsetCache
{
get
{
return _symbolOffsetCache;
}
set
{
_symbolOffsetCache = value;
}
}
// Count of symbols covered by this node.
internal override int SymbolCount
{
get
{
return 1;
}
set
{
Invariant.Assert(false, "Can't set SymbolCount on TextTreeObjectNode!");
}
}
// Count of symbols covered by this node.
internal override int IMECharCount
{
get
{
return 1;
}
set
{
Invariant.Assert(false, "Can't set CharCount on TextTreeObjectNode!");
}
}
// Count of TextPositions referencing the node's BeforeStart edge.
// Since nodes don't usually have any references, we demand allocate
// storage when needed.
internal override bool BeforeStartReferenceCount
{
get
{
return (_edgeReferenceCounts & ElementEdge.BeforeStart) != 0;
}
set
{
Invariant.Assert(value); // Illegal to clear a set ref count.
_edgeReferenceCounts |= ElementEdge.BeforeStart;
}
}
// Count of TextPositions referencing the node's AfterStart edge.
// Since object nodes don't have an AfterStart edge, this is always zero.
internal override bool AfterStartReferenceCount
{
get
{
return false;
}
set
{
Invariant.Assert(false, "Object nodes don't have an AfterStart edge!");
}
}
// Count of TextPositions referencing the node's BeforeEnd edge.
// Since object nodes don't have an BeforeEnd edge, this is always zero.
internal override bool BeforeEndReferenceCount
{
get
{
return false;
}
set
{
Invariant.Assert(false, "Object nodes don't have a BeforeEnd edge!");
}
}
// Count of TextPositions referencing the node's right
// edge.
// Since nodes don't usually have any references, we demand allocate
// storage when needed.
internal override bool AfterEndReferenceCount
{
get
{
return (_edgeReferenceCounts & ElementEdge.AfterEnd) != 0;
}
set
{
Invariant.Assert(value); // Illegal to clear a set ref count.
_edgeReferenceCounts |= ElementEdge.AfterEnd;
}
}
// The UIElement or ContentElement linked to this node.
internal DependencyObject EmbeddedElement
{
get
{
return _embeddedElement;
}
}
#endregion Internal Properties
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
// Count of symbols of all siblings preceding this node.
private int _leftSymbolCount;
// Count of chars of all siblings preceding this node.
private int _leftCharCount;
// If this node is a local root, then ParentNode contains it.
// Otherwise, this is the node parenting this node within its tree.
private TextTreeNode _parentNode;
// Left child node in a sibling tree.
private TextTreeNode _leftChildNode;
// Right child node in a sibling tree.
private TextTreeNode _rightChildNode;
// The TextContainer's generation when SymbolOffsetCache was last updated.
// If the current generation doesn't match TextContainer.Generation, then
// SymbolOffsetCache is invalid.
private uint _generation;
// Cached symbol offset.
private int _symbolOffsetCache;
// Reference counts of TextPositions referencing this node.
// Lazy allocated -- null means no references.
private ElementEdge _edgeReferenceCounts;
// The UIElement or ContentElement linked to this node.
private readonly DependencyObject _embeddedElement;
#endregion Private Fields
}
}
|