1 files changed, 52 insertions, 0 deletions
diff --git a/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Document/DocumentChangeOperation.cs b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Document/DocumentChangeOperation.cs
new file mode 100644
index 000000000..f24b7ed4d
--- /dev/null
+++ b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Document/DocumentChangeOperation.cs
@@ -0,0 +1,52 @@
+// 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;
+using System.Diagnostics;
+
+namespace Tango.Scripting.Editors.Document
+{
+	/// <summary>
+	/// Describes a change to a TextDocument.
+	/// </summary>
+	sealed class DocumentChangeOperation : IUndoableOperationWithContext
+	{
+		TextDocument document;
+		DocumentChangeEventArgs change;
+		
+		public DocumentChangeOperation(TextDocument document, DocumentChangeEventArgs change)
+		{
+			this.document = document;
+			this.change = change;
+		}
+		
+		public void Undo(UndoStack stack)
+		{
+			Debug.Assert(stack.state == UndoStack.StatePlayback);
+			stack.RegisterAffectedDocument(document);
+			stack.state = UndoStack.StatePlaybackModifyDocument;
+			this.Undo();
+			stack.state = UndoStack.StatePlayback;
+		}
+		
+		public void Redo(UndoStack stack)
+		{
+			Debug.Assert(stack.state == UndoStack.StatePlayback);
+			stack.RegisterAffectedDocument(document);
+			stack.state = UndoStack.StatePlaybackModifyDocument;
+			this.Redo();
+			stack.state = UndoStack.StatePlayback;
+		}
+		
+		public void Undo()
+		{
+			OffsetChangeMap map = change.OffsetChangeMapOrNull;
+			document.Replace(change.Offset, change.InsertionLength, change.RemovedText, map != null ? map.Invert() : null);
+		}
+		
+		public void Redo()
+		{
+			document.Replace(change.Offset, change.RemovalLength, change.InsertedText, change.OffsetChangeMapOrNull);
+		}
+	}
+}