Merge branch 'master' of https://twinetfs.visualstudio.com/Tango/_git/Tango

1 files changed, 55 insertions, 0 deletions

diff --git a/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Utils/BusyManager.cs b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Utils/BusyManager.cs
new file mode 100644
index 000000000..8551ff49e
--- /dev/null
+++ b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Utils/BusyManager.cs
@@ -0,0 +1,55 @@
+// 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.Collections.Generic;
+
+namespace Tango.Scripting.Editors.Utils
+{
+	/// <summary>
+	/// This class is used to prevent stack overflows by representing a 'busy' flag
+	/// that prevents reentrance when another call is running.
+	/// However, using a simple 'bool busy' is not thread-safe, so we use a
+	/// thread-static BusyManager.
+	/// </summary>
+	static class BusyManager
+	{
+		public struct BusyLock : IDisposable
+		{
+			public static readonly BusyLock Failed = new BusyLock(null);
+			
+			readonly List<object> objectList;
+			
+			public BusyLock(List<object> objectList)
+			{
+				this.objectList = objectList;
+			}
+			
+			public bool Success {
+				get { return objectList != null; }
+			}
+			
+			public void Dispose()
+			{
+				if (objectList != null) {
+					objectList.RemoveAt(objectList.Count - 1);
+				}
+			}
+		}
+		
+		[ThreadStatic] static List<object> _activeObjects;
+		
+		public static BusyLock Enter(object obj)
+		{
+			List<object> activeObjects = _activeObjects;
+			if (activeObjects == null)
+				activeObjects = _activeObjects = new List<object>();
+			for (int i = 0; i < activeObjects.Count; i++) {
+				if (activeObjects[i] == obj)
+					return BusyLock.Failed;
+			}
+			activeObjects.Add(obj);
+			return new BusyLock(activeObjects);
+		}
+	}
+}