1 files changed, 35 insertions, 0 deletions
diff --git a/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Utils/CallbackOnDispose.cs b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Utils/CallbackOnDispose.cs
new file mode 100644
index 000000000..a6eebf2f1
--- /dev/null
+++ b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Utils/CallbackOnDispose.cs
@@ -0,0 +1,35 @@
+// 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;
+using System.Threading;
+
+namespace Tango.Scripting.Editors.Utils
+{
+	/// <summary>
+	/// Invokes an action when it is disposed.
+	/// </summary>
+	/// <remarks>
+	/// This class ensures the callback is invoked at most once,
+	/// even when Dispose is called on multiple threads.
+	/// </remarks>
+	sealed class CallbackOnDispose : IDisposable
+	{
+		Action action;
+		
+		public CallbackOnDispose(Action action)
+		{
+			Debug.Assert(action != null);
+			this.action = action;
+		}
+		
+		public void Dispose()
+		{
+			Action a = Interlocked.Exchange(ref action, null);
+			if (a != null) {
+				a();
+			}
+		}
+	}
+}