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, 8 insertions, 10 deletions

diff --git a/csharp/src/Google.Protobuf/IMessage.cs b/csharp/src/Google.Protobuf/IMessage.cs
index 8c4a4aaf..d179c386 100644
--- a/csharp/src/Google.Protobuf/IMessage.cs
+++ b/csharp/src/Google.Protobuf/IMessage.cs
@@ -40,15 +40,6 @@ namespace Google.Protobuf
     // TODO(jonskeet): Split these interfaces into separate files when we're happy with them.

 

     /// <summary>

-    /// Reflection support for accessing field values.

-    /// </summary>

-    public interface IReflectedMessage : IMessage

-    {

-        FieldAccessorTable Fields { get; }

-        // TODO(jonskeet): Descriptor? Or a single property which has "all you need for reflection"?

-    }

-

-    /// <summary>

     /// Interface for a Protocol Buffers message, supporting

     /// basic operations required for serialization.

     /// </summary>

@@ -73,6 +64,13 @@ namespace Google.Protobuf
         /// <returns>The number of bytes required to write this message

         /// to a coded output stream.</returns>

         int CalculateSize();

+

+        /// <summary>

+        /// Descriptor for this message. All instances are expected to return the same descriptor,

+        /// and for generated types this will be an explicitly-implemented member, returning the

+        /// same value as the static property declared on the type.

+        /// </summary>

+        MessageDescriptor Descriptor { get; }

     }

 

     /// <summary>

@@ -81,7 +79,7 @@ namespace Google.Protobuf
     /// the implementation class.

     /// </summary>

     /// <typeparam name="T">The message type.</typeparam>

-    public interface IMessage<T> : IReflectedMessage, IEquatable<T>, IDeepCloneable<T>, IFreezable where T : IMessage<T>

+    public interface IMessage<T> : IMessage, IEquatable<T>, IDeepCloneable<T>, IFreezable where T : IMessage<T>

     {

         /// <summary>

         /// Merges the given message into this one.