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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
// Description: A TextContainer node representing a TextElement.
//
using System;
using MS.Internal;
namespace System.Windows.Documents
{
// Each TextElement inserted though a public API is represented internally
// by a TextTreeTextElementNode.
//
// TextTreeTextElementNodes may contain trees of child nodes, nodes in
// a contained tree are scoped by the element node.
internal class TextTreeTextElementNode : TextTreeNode
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
// Creates a new instance.
internal TextTreeTextElementNode()
{
_symbolOffsetCache = -1;
}
#endregion Constructors
//------------------------------------------------------
//
// Public Methods
//
//------------------------------------------------------
#region Public Methods
#if DEBUG
// Debug-only ToString override.
public override string ToString()
{
return ("TextElementNode Id=" + this.DebugId + " SymbolCount=" + _symbolCount);
}
#endif // DEBUG
#endregion Public Methods
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
#region Internal Methods
// Returns a shallow copy of this node.
internal override TextTreeNode Clone()
{
TextTreeTextElementNode clone;
clone = new TextTreeTextElementNode();
clone._symbolCount = _symbolCount;
clone._imeCharCount = _imeCharCount;
clone._textElement = _textElement;
return clone;
}
// Returns the TextPointerContext of the node.
// Returns ElementStart if direction == Forward, otherwise ElementEnd
// if direction == Backward.
internal override TextPointerContext GetPointerContext(LogicalDirection direction)
{
return (direction == LogicalDirection.Forward) ? TextPointerContext.ElementStart : TextPointerContext.ElementEnd;
}
#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;
}
}
// Root node of a contained tree, if any.
internal override SplayTreeNode ContainedNode
{
get
{
return _containedNode;
}
set
{
_containedNode = (TextTreeNode)value;
}
}
// Count of symbols of all siblings preceding this node.
internal override int LeftSymbolCount
{
get
{
return _leftSymbolCount;
}
set
{
_leftSymbolCount = value;
}
}
// Count of chars 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 and any contained nodes.
// Includes two symbols for this node's start/end edges.
internal override int SymbolCount
{
get
{
return _symbolCount;
}
set
{
_symbolCount = value;
}
}
// Count of chars covered by this node and any contained nodes.
internal override int IMECharCount
{
get
{
return _imeCharCount;
}
set
{
_imeCharCount = value;
}
}
// 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 nodes don't usually have any references, we demand allocate
// storage when needed.
internal override bool AfterStartReferenceCount
{
get
{
return (_edgeReferenceCounts & ElementEdge.AfterStart) != 0;
}
set
{
Invariant.Assert(value); // Illegal to clear a set ref count.
_edgeReferenceCounts |= ElementEdge.AfterStart;
}
}
// Count of TextPositions referencing the node's BeforeEnd edge.
// Since nodes don't usually have any references, we demand allocate
// storage when needed.
internal override bool BeforeEndReferenceCount
{
get
{
return (_edgeReferenceCounts & ElementEdge.BeforeEnd) != 0;
}
set
{
Invariant.Assert(value); // Illegal to clear a set ref count.
_edgeReferenceCounts |= ElementEdge.BeforeEnd;
}
}
// Count of TextPositions referencing the node's AfterEnd 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 TextElement associated with this node.
internal TextElement TextElement
{
get
{
return _textElement;
}
set
{
_textElement = value;
}
}
// Plain text character count of this element's start edge.
// This property depends on the current location of the node!
internal int IMELeftEdgeCharCount
{
get
{
return (_textElement == null) ? -1 : _textElement.IMELeftEdgeCharCount;
}
}
// Returns true if this node is the leftmost sibling of its parent.
internal bool IsFirstSibling
{
get
{
Splay();
return (_leftChildNode == null);
}
}
#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;
// Root node of a contained tree, if any.
private TextTreeNode _containedNode;
// 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;
// Count of symbols covered by this node and any contained nodes.
// Includes two symbols for this node's start/end edges.
private int _symbolCount;
// Count of chars covered by this node and any contained nodes.
private int _imeCharCount;
// The TextElement associated with this node.
private TextElement _textElement;
// Reference counts of TextPositions referencing this node.
// Lazy allocated -- null means no references.
private ElementEdge _edgeReferenceCounts;
#endregion Private Fields
}
}
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