Pack/Unpack implementation for Any.

We still need the JSON representation, which relies on something like a DescriptorPool to fetch message types from based on the type URL. That will come a bit later.
(The DescriptorPool comment in this commit is just a note which will prove useful if we use DescriptorPool itself.)

Makefile.am

@@ -95,6 +95,7 @@ csharp_EXTRA_DIST=                                                           \
   csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs               \
   csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs               \
   csharp/src/Google.Protobuf.Test/TestProtos/UnittestWellKnownTypes.cs       \
+  csharp/src/Google.Protobuf.Test/WellKnownTypes/AnyTest.cs                  \
   csharp/src/Google.Protobuf.Test/WellKnownTypes/DurationTest.cs             \
   csharp/src/Google.Protobuf.Test/WellKnownTypes/TimestampTest.cs            \
   csharp/src/Google.Protobuf.Test/WellKnownTypes/WrappersTest.cs             \
@@ -149,6 +150,7 @@ csharp_EXTRA_DIST=                                                           \
   csharp/src/Google.Protobuf/Reflection/ServiceDescriptor.cs                 \
   csharp/src/Google.Protobuf/Reflection/SingleFieldAccessor.cs               \
   csharp/src/Google.Protobuf/WellKnownTypes/Any.cs                           \
+  csharp/src/Google.Protobuf/WellKnownTypes/AnyPartial.cs                    \
   csharp/src/Google.Protobuf/WellKnownTypes/Api.cs                           \
   csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs                      \
   csharp/src/Google.Protobuf/WellKnownTypes/DurationPartial.cs               \

csharp/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj

@@ -109,6 +109,7 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="TestCornerCases.cs" />
     <Compile Include="TestProtos\UnittestWellKnownTypes.cs" />
+    <Compile Include="WellKnownTypes\AnyTest.cs" />
     <Compile Include="WellKnownTypes\DurationTest.cs" />
     <Compile Include="WellKnownTypes\TimestampTest.cs" />
     <Compile Include="WellKnownTypes\WrappersTest.cs" />

csharp/src/Google.Protobuf.Test/WellKnownTypes/AnyTest.cs

@@ -0,0 +1,66 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using Google.Protobuf.TestProtos;
+using NUnit.Framework;
+
+namespace Google.Protobuf.WellKnownTypes
+{
+    public class AnyTest
+    {
+        [Test]
+        public void Pack()
+        {
+            var message = SampleMessages.CreateFullTestAllTypes();
+            var any = Any.Pack(message);
+            Assert.AreEqual("type.googleapis.com/protobuf_unittest.TestAllTypes", any.TypeUrl);
+            Assert.AreEqual(message.CalculateSize(), any.Value.Length);
+        }
+
+        [Test]
+        public void Unpack_WrongType()
+        {
+            var message = SampleMessages.CreateFullTestAllTypes();
+            var any = Any.Pack(message);
+            Assert.Throws<InvalidProtocolBufferException>(() => any.Unpack<TestOneof>());
+        }
+
+        [Test]
+        public void Unpack_Success()
+        {
+            var message = SampleMessages.CreateFullTestAllTypes();
+            var any = Any.Pack(message);
+            var unpacked = any.Unpack<TestAllTypes>();
+            Assert.AreEqual(message, unpacked);
+        }
+    }
+}

csharp/src/Google.Protobuf/Google.Protobuf.csproj

@@ -118,6 +118,7 @@
     <Compile Include="Reflection\SingleFieldAccessor.cs" />
     <Compile Include="Preconditions.cs" />
     <Compile Include="WellKnownTypes\Any.cs" />
+    <Compile Include="WellKnownTypes\AnyPartial.cs" />
     <Compile Include="WellKnownTypes\Api.cs" />
     <Compile Include="WellKnownTypes\Duration.cs" />
     <Compile Include="WellKnownTypes\DurationPartial.cs" />

csharp/src/Google.Protobuf/Reflection/DescriptorPool.cs

@@ -96,6 +96,8 @@ namespace Google.Protobuf.Reflection
                 return descriptor;
             }
 
+            // dependencies contains direct dependencies and any *public* dependencies
+            // of those dependencies (transitively)... so we don't need to recurse here.
             foreach (FileDescriptor dependency in dependencies)
             {
                 dependency.DescriptorPool.descriptorsByName.TryGetValue(fullName, out result);

csharp/src/Google.Protobuf/WellKnownTypes/AnyPartial.cs

@@ -0,0 +1,79 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2015 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using Google.Protobuf.Reflection;
+
+namespace Google.Protobuf.WellKnownTypes
+{
+    public partial class Any
+    {
+        // 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)
+        {
+            return "type.googleapis.com/" + descriptor.FullName;
+        }
+
+        /// <summary>
+        /// Unpacks the content of this Any message into the target message type,
+        /// which must match the type URL within this Any message.
+        /// </summary>
+        /// <typeparam name="T">The type of message to unpack the content into.</typeparam>
+        /// <returns>The unpacked message.</returns>
+        /// <exception cref="InvalidProtocolBufferException">The target message type doesn't match the type URL in this message</exception>
+        public T Unpack<T>() where T : IMessage, new()
+        {
+            // 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)
+            {
+                throw new InvalidProtocolBufferException(string.Format("Type url for {0} is {1}; Any message's type url is {2}",
+                    target.Descriptor.Name, targetTypeUrl, TypeUrl));
+            }
+            target.MergeFrom(Value);
+            return target;
+        }
+
+        /// <summary>
+        /// Packs the specified message into an Any message.
+        /// </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)
+        {
+            Preconditions.CheckNotNull(message, "message");
+            return new Any { TypeUrl = GetTypeUrl(message.Descriptor), Value = message.ToByteString() };
+        }
+    }
+}