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// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
using System;
namespace ICSharpCode.AvalonEdit.Document
{
/// <summary>
/// Allows registering a line tracker on a TextDocument using a weak reference from the document to the line tracker.
/// </summary>
public sealed class WeakLineTracker : ILineTracker
{
TextDocument textDocument;
WeakReference targetObject;
private WeakLineTracker(TextDocument textDocument, ILineTracker targetTracker)
{
this.textDocument = textDocument;
this.targetObject = new WeakReference(targetTracker);
}
/// <summary>
/// Registers the <paramref name="targetTracker"/> as line tracker for the <paramref name="textDocument"/>.
/// A weak reference to the target tracker will be used, and the WeakLineTracker will deregister itself
/// when the target tracker is garbage collected.
/// </summary>
public static WeakLineTracker Register(TextDocument textDocument, ILineTracker targetTracker)
{
if (textDocument == null)
throw new ArgumentNullException("textDocument");
if (targetTracker == null)
throw new ArgumentNullException("targetTracker");
WeakLineTracker wlt = new WeakLineTracker(textDocument, targetTracker);
textDocument.LineTrackers.Add(wlt);
return wlt;
}
/// <summary>
/// Deregisters the weak line tracker.
/// </summary>
public void Deregister()
{
if (textDocument != null) {
textDocument.LineTrackers.Remove(this);
textDocument = null;
}
}
void ILineTracker.BeforeRemoveLine(DocumentLine line)
{
ILineTracker targetTracker = targetObject.Target as ILineTracker;
if (targetTracker != null)
targetTracker.BeforeRemoveLine(line);
else
Deregister();
}
void ILineTracker.SetLineLength(DocumentLine line, int newTotalLength)
{
ILineTracker targetTracker = targetObject.Target as ILineTracker;
if (targetTracker != null)
targetTracker.SetLineLength(line, newTotalLength);
else
Deregister();
}
void ILineTracker.LineInserted(DocumentLine insertionPos, DocumentLine newLine)
{
ILineTracker targetTracker = targetObject.Target as ILineTracker;
if (targetTracker != null)
targetTracker.LineInserted(insertionPos, newLine);
else
Deregister();
}
void ILineTracker.RebuildDocument()
{
ILineTracker targetTracker = targetObject.Target as ILineTracker;
if (targetTracker != null)
targetTracker.RebuildDocument();
else
Deregister();
}
}
}
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