1 files changed, 35 insertions, 0 deletions
diff --git a/csharp/ProtocolBuffers/RpcUtil.cs b/csharp/ProtocolBuffers/RpcUtil.cs
new file mode 100644
index 00000000..75e6f34b
--- /dev/null
+++ b/csharp/ProtocolBuffers/RpcUtil.cs
@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Google.ProtocolBuffers {
+  public static class RpcUtil {
+
+    /// <summary>
+    /// Converts an Action[IMessage] to an Action[T].
+    /// </summary>
+    public static Action<T> SpecializeCallback<T>(Action<IMessage> action) 
+        where T : IMessage<T> {
+      return message => action(message);
+    }
+
+    /// <summary>
+    /// Converts an Action[T] to an Action[IMessage].
+    /// The generalized action will accept any message object which has
+    /// the same descriptor, and will convert it to the correct class
+    /// before calling the original action. However, if the generalized
+    /// callback is given a message with a different descriptor, an
+    /// exception will be thrown.
+    /// </summary>
+    public static Action<IMessage> GeneralizeCallback<T>(Action<T> action, T defaultInstance)
+        where T : class, IMessage<T> {
+      return message => {
+        T castMessage = message as T;
+        if (castMessage == null) {
+          castMessage = (T) defaultInstance.CreateBuilderForType().MergeFrom(message).Build();
+        }
+        action(castMessage);
+      };
+    }
+  }
+}