1 files changed, 67 insertions, 10 deletions

diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/AnyPartial.cs b/csharp/src/Google.Protobuf/WellKnownTypes/AnyPartial.cs
index 9d43856e..fca689dc 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/AnyPartial.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/AnyPartial.cs
@@ -36,11 +36,35 @@ namespace Google.Protobuf.WellKnownTypes
 {
     public partial class Any
     {
+        private const string DefaultPrefix = "type.googleapis.com";
+
         // This could be moved to MessageDescriptor if we wanted to, but keeping it here means
         // all the Any-specific code is in the same place.
-        private static string GetTypeUrl(MessageDescriptor descriptor)
+        private static string GetTypeUrl(MessageDescriptor descriptor, string prefix) =>
+            prefix.EndsWith("/") ? prefix + descriptor.FullName : prefix + "/" + descriptor.FullName;
+
+        /// <summary>
+        /// Retrieves the type name for a type URL, matching the <see cref="DescriptorBase.FullName"/>
+        /// of the packed message type.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// This is always just the last part of the URL, after the final slash. No validation of 
+        /// anything before the trailing slash is performed. If the type URL does not include a slash,
+        /// an empty string is returned rather than an exception being thrown; this won't match any types,
+        /// and the calling code is probably in a better position to give a meaningful error.
+        /// </para>
+        /// <para>
+        /// There is no handling of fragments or queries  at the moment.
+        /// </para>
+        /// </remarks>
+        /// <param name="typeUrl">The URL to extract the type name from</param>
+        /// <returns>The type name</returns>
+        public static string GetTypeName(string typeUrl)
         {
-            return "type.googleapis.com/" + descriptor.FullName;
+            ProtoPreconditions.CheckNotNull(typeUrl, nameof(typeUrl));
+            int lastSlash = typeUrl.LastIndexOf('/');
+            return lastSlash == -1 ? "" : typeUrl.Substring(lastSlash + 1);
         }
 
         /// <summary>
@@ -55,25 +79,58 @@ namespace Google.Protobuf.WellKnownTypes
             // Note: this doesn't perform as well is it might. We could take a MessageParser<T> in an alternative overload,
             // which would be expected to perform slightly better... although the difference is likely to be negligible.
             T target = new T();
-            string targetTypeUrl = GetTypeUrl(target.Descriptor);
-            if (TypeUrl != targetTypeUrl)
+            if (GetTypeName(TypeUrl) != target.Descriptor.FullName)
             {
-                throw new InvalidProtocolBufferException(string.Format("Type url for {0} is {1}; Any message's type url is {2}",
-                    target.Descriptor.Name, targetTypeUrl, TypeUrl));
+                throw new InvalidProtocolBufferException(
+                    $"Full type name for {target.Descriptor.Name} is {target.Descriptor.FullName}; Any message's type url is {TypeUrl}");
             }
             target.MergeFrom(Value);
             return target;
         }
 
         /// <summary>
-        /// Packs the specified message into an Any message.
+        /// Attempts to unpack the content of this Any message into the target message type,
+        /// if it matches the type URL within this Any message.
+        /// </summary>
+        /// <typeparam name="T">The type of message to attempt to unpack the content into.</typeparam>
+        /// <returns><c>true</c> if the message was successfully unpacked; <c>false</c> if the type name didn't match</returns>
+        public bool TryUnpack<T>(out T result) where T : IMessage, new()
+        {
+            // Note: deliberately avoid writing anything to result until the end, in case it's being
+            // monitored by other threads. (That would be a bug in the calling code, but let's not make it worse.)
+            T target = new T();
+            if (GetTypeName(TypeUrl) != target.Descriptor.FullName)
+            {
+                result = default(T); // Can't use null as there's no class constraint, but this always *will* be null in real usage.
+                return false;
+            }
+            target.MergeFrom(Value);
+            result = target;
+            return true;
+        }
+
+        /// <summary>
+        /// Packs the specified message into an Any message using a type URL prefix of "type.googleapis.com".
         /// </summary>
         /// <param name="message">The message to pack.</param>
         /// <returns>An Any message with the content and type URL of <paramref name="message"/>.</returns>
-        public static Any Pack(IMessage message)
+        public static Any Pack(IMessage message) => Pack(message, DefaultPrefix);
+
+        /// <summary>
+        /// Packs the specified message into an Any message using the specified type URL prefix.
+        /// </summary>
+        /// <param name="message">The message to pack.</param>
+        /// <param name="typeUrlPrefix">The prefix for the type URL.</param>
+        /// <returns>An Any message with the content and type URL of <paramref name="message"/>.</returns>
+        public static Any Pack(IMessage message, string typeUrlPrefix)
         {
-            ProtoPreconditions.CheckNotNull(message, "message");
-            return new Any { TypeUrl = GetTypeUrl(message.Descriptor), Value = message.ToByteString() };
+            ProtoPreconditions.CheckNotNull(message, nameof(message));
+            ProtoPreconditions.CheckNotNull(typeUrlPrefix, nameof(typeUrlPrefix));
+            return new Any
+            {
+                TypeUrl = GetTypeUrl(message.Descriptor, typeUrlPrefix),
+                Value = message.ToByteString()
+            };
         }
     }
 }