csharp/src/ProtocolBuffers/FieldAccess/OneofAccessor.cs

// Protocol Buffers - Google's data interchange format
// Copyright 2015 Google Inc.  All rights reserved.
// Author: jieluo@google.com (Jie Luo)
//
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// modification, are permitted provided that the following conditions are
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//
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using System;
using System.Reflection;
using Google.Protobuf.Descriptors;

namespace Google.Protobuf.FieldAccess
{
    // TODO(jonskeet): Add "new" oneof API support

    /// <summary>
    /// Access for an oneof
    /// </summary>
    internal class OneofAccessor<TMessage> where TMessage : IMessage<TMessage>
    {
        /*
        private readonly Func<TMessage, object> caseDelegate;
        private readonly Func<TBuilder, IBuilder> clearDelegate;
        private MessageDescriptor descriptor;

        internal OneofAccessor(MessageDescriptor descriptor, string name) 
        {
            this.descriptor = descriptor;
            MethodInfo clearMethod = typeof(TBuilder).GetMethod("Clear" + name);
            PropertyInfo caseProperty = typeof(TMessage).GetProperty(name + "Case");
            if (clearMethod == null || caseProperty == null)
            {
                throw new ArgumentException("Not all required properties/methods available for oneof");
            }
            

            clearDelegate = ReflectionUtil.CreateDelegateFunc<TBuilder, IBuilder>(clearMethod);
            caseDelegate = ReflectionUtil.CreateUpcastDelegate<TMessage>(caseProperty.GetGetMethod());
        }

        /// <summary>
        /// Indicates whether the specified message has set any field in the oneof.
        /// </summary>
        public bool Has(TMessage message)
        {
            return ((int) caseDelegate(message) != 0);
        }

        /// <summary>
        /// Clears the oneof in the specified builder.
        /// </summary>
        public void Clear(TBuilder builder)
        {
            clearDelegate(builder);
        }

        /// <summary>
        /// Indicates which field in the oneof is set for specified message
        /// </summary>
        public virtual FieldDescriptor GetOneofFieldDescriptor(TMessage message)
        {
            int fieldNumber = (int) caseDelegate(message);
            if (fieldNumber > 0)
            {
                return descriptor.FindFieldByNumber(fieldNumber);
            }
            return null;
        }*/
    }
}