1 files changed, 94 insertions, 0 deletions
diff --git a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ChainedExtension.cs b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ChainedExtension.cs
new file mode 100644
index 0000000000..48af259aba
--- /dev/null
+++ b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ChainedExtension.cs
@@ -0,0 +1,94 @@
+//
+// ChainedExtension.cs
+//
+// Author:
+//       Lluis Sanchez Gual <lluis@xamarin.com>
+//
+// Copyright (c) 2014 Xamarin, Inc (http://www.xamarin.com)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+using System;
+using System.Reflection;
+using System.Linq;
+using System.Collections.Generic;
+
+namespace MonoDevelop.Projects
+{
+	public class ChainedExtension: IDisposable
+	{
+		ChainedExtension nextInChain;
+
+		internal protected static T FindNextImplementation<T> (ChainedExtension next) where T:class
+		{
+			if (next == null)
+				return null;
+
+			var nextT = next as T;
+			if (nextT == null)
+				return FindNextImplementation<T> (next.nextInChain);
+
+			foreach (var m in typeof(T).GetMembers (BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)) {
+				MethodInfo method = m as MethodInfo;
+				if (method == null) {
+					var prop = m as PropertyInfo;
+					if (prop != null) {
+						method = prop.GetGetMethod ();
+						if (method == null)
+							method = prop.GetSetMethod ();
+					}
+				}
+				if (method != null && method.IsVirtual && method.Name != "InitializeChain") {
+					var tm = next.GetType ().GetMethod (method.Name, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance, null, method.GetParameters ().Select (p=>p.ParameterType).ToArray (), null);
+					if (tm == null)
+						continue;
+					if (tm.DeclaringType != typeof(T))
+						return nextT;
+				}
+			}
+
+			return FindNextImplementation<T> (next.nextInChain);
+		}
+
+		internal void Init (ChainedExtension next)
+		{
+			nextInChain = next;
+			InitializeChain (next);
+		}
+
+		internal protected virtual void InitializeChain (ChainedExtension next)
+		{
+		}
+
+		internal ChainedExtension Next {
+			get { return nextInChain; }
+		}
+
+		internal void DisposeChain ()
+		{
+			Dispose ();
+			if (nextInChain != null)
+				nextInChain.DisposeChain ();
+		}
+
+		public virtual void Dispose ()
+		{
+		}
+	}
+}
+