/AvalonEdit/ICSharpCode.AvalonEdit/Document/WeakLineTracker.cs

  1// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
  2// 
  3// Permission is hereby granted, free of charge, to any person obtaining a copy of this
  4// software and associated documentation files (the "Software"), to deal in the Software
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  6// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
  7// to whom the Software is furnished to do so, subject to the following conditions:
  8// 
  9// The above copyright notice and this permission notice shall be included in all copies or
 10// substantial portions of the Software.
 11// 
 12// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 13// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
 14// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
 15// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 16// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 17// DEALINGS IN THE SOFTWARE.
 18
 19using System;
 20
 21namespace ICSharpCode.AvalonEdit.Document
 22{
 23	/// <summary>
 24	/// Allows registering a line tracker on a TextDocument using a weak reference from the document to the line tracker.
 25	/// </summary>
 26	public sealed class WeakLineTracker : ILineTracker
 27	{
 28		TextDocument textDocument;
 29		WeakReference targetObject;
 30		
 31		private WeakLineTracker(TextDocument textDocument, ILineTracker targetTracker)
 32		{
 33			this.textDocument = textDocument;
 34			this.targetObject = new WeakReference(targetTracker);
 35		}
 36		
 37		/// <summary>
 38		/// Registers the <paramref name="targetTracker"/> as line tracker for the <paramref name="textDocument"/>.
 39		/// A weak reference to the target tracker will be used, and the WeakLineTracker will deregister itself
 40		/// when the target tracker is garbage collected.
 41		/// </summary>
 42		public static WeakLineTracker Register(TextDocument textDocument, ILineTracker targetTracker)
 43		{
 44			if (textDocument == null)
 45				throw new ArgumentNullException("textDocument");
 46			if (targetTracker == null)
 47				throw new ArgumentNullException("targetTracker");
 48			WeakLineTracker wlt = new WeakLineTracker(textDocument, targetTracker);
 49			textDocument.LineTrackers.Add(wlt);
 50			return wlt;
 51		}
 52		
 53		/// <summary>
 54		/// Deregisters the weak line tracker.
 55		/// </summary>
 56		public void Deregister()
 57		{
 58			if (textDocument != null) {
 59				textDocument.LineTrackers.Remove(this);
 60				textDocument = null;
 61			}
 62		}
 63		
 64		void ILineTracker.BeforeRemoveLine(DocumentLine line)
 65		{
 66			ILineTracker targetTracker = targetObject.Target as ILineTracker;
 67			if (targetTracker != null)
 68				targetTracker.BeforeRemoveLine(line);
 69			else
 70				Deregister();
 71		}
 72		
 73		void ILineTracker.SetLineLength(DocumentLine line, int newTotalLength)
 74		{
 75			ILineTracker targetTracker = targetObject.Target as ILineTracker;
 76			if (targetTracker != null)
 77				targetTracker.SetLineLength(line, newTotalLength);
 78			else
 79				Deregister();
 80		}
 81		
 82		void ILineTracker.LineInserted(DocumentLine insertionPos, DocumentLine newLine)
 83		{
 84			ILineTracker targetTracker = targetObject.Target as ILineTracker;
 85			if (targetTracker != null)
 86				targetTracker.LineInserted(insertionPos, newLine);
 87			else
 88				Deregister();
 89		}
 90		
 91		void ILineTracker.RebuildDocument()
 92		{
 93			ILineTracker targetTracker = targetObject.Target as ILineTracker;
 94			if (targetTracker != null)
 95				targetTracker.RebuildDocument();
 96			else
 97				Deregister();
 98		}
 99		
100		void ILineTracker.ChangeComplete(DocumentChangeEventArgs e)
101		{
102			ILineTracker targetTracker = targetObject.Target as ILineTracker;
103			if (targetTracker != null)
104				targetTracker.ChangeComplete(e);
105			else
106				Deregister();
107		}
108	}
109}