Revamp to reflection.

Changes in brief:
1. Descriptor is now the entry point for all reflection.
2. IReflectedMessage has gone; there's now a Descriptor property in IMessage, which is explicitly implemented (due to the static property).
3. FieldAccessorTable has gone away
4. IFieldAccessor and OneofFieldAccessor still exist; we *could* put the functionality straight into FieldDescriptor and OneofDescriptor... I'm unsure about that.
5. There's a temporary property MessageDescriptor.FieldAccessorsByFieldNumber to make the test changes small - we probably want this to go away
6. Discovery for delegates is now via attributes applied to properties and the Clear method of a oneof

I'm happy with 1-3.
4 I'm unsure about - feedback welcome.
5 will go away
6 I'm unsure about, both in design and implementation. Should we have a ProtobufMessageAttribute too? Should we find all the relevant attributes in MessageDescriptor and pass them down, to avoid an O(N^2) scenario?

Generated code changes coming in the next commit.

1 files changed, 3 insertions, 3 deletions

diff --git a/csharp/src/Google.Protobuf.Test/WellKnownTypes/WrappersTest.cs b/csharp/src/Google.Protobuf.Test/WellKnownTypes/WrappersTest.cs
index ad88c4eb..c617db36 100644
--- a/csharp/src/Google.Protobuf.Test/WellKnownTypes/WrappersTest.cs
+++ b/csharp/src/Google.Protobuf.Test/WellKnownTypes/WrappersTest.cs
@@ -192,7 +192,7 @@ namespace Google.Protobuf.WellKnownTypes
                 Uint32Field = 3,
                 Uint64Field = 4
             };
-            var fields = ((IReflectedMessage) message).Fields;
+            var fields = TestWellKnownTypes.Descriptor.FieldAccessorsByFieldNumber;
 
             Assert.AreEqual("x", fields[TestWellKnownTypes.StringFieldFieldNumber].GetValue(message));
             Assert.AreEqual(ByteString.CopyFrom(1, 2, 3), fields[TestWellKnownTypes.BytesFieldFieldNumber].GetValue(message));
@@ -216,7 +216,7 @@ namespace Google.Protobuf.WellKnownTypes
         {
             // Just a single example... note that we can't have a null value here
             var message = new RepeatedWellKnownTypes { Int32Field = { 1, 2 } };
-            var fields = ((IReflectedMessage) message).Fields;
+            var fields = RepeatedWellKnownTypes.Descriptor.FieldAccessorsByFieldNumber;
             var list = (IList) fields[RepeatedWellKnownTypes.Int32FieldFieldNumber].GetValue(message);
             CollectionAssert.AreEqual(new[] { 1, 2 }, list);
         }
@@ -226,7 +226,7 @@ namespace Google.Protobuf.WellKnownTypes
         {
             // Just a single example... note that we can't have a null value here
             var message = new MapWellKnownTypes { Int32Field = { { 1, 2 }, { 3, null } } };
-            var fields = ((IReflectedMessage) message).Fields;
+            var fields = MapWellKnownTypes.Descriptor.FieldAccessorsByFieldNumber;
             var dictionary = (IDictionary) fields[MapWellKnownTypes.Int32FieldFieldNumber].GetValue(message);
             Assert.AreEqual(2, dictionary[1]);
             Assert.IsNull(dictionary[3]);