protobuf/src/ProtocolBuffers/GeneratedRepeatExtension.cs

#region Copyright notice and license
// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// http://github.com/jskeet/dotnet-protobufs/
// Original C++/Java/Python code:
// http://code.google.com/p/protobuf/
//
// 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
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#endregion

using System;
using System.Collections.Generic;
using Google.ProtocolBuffers.Descriptors;
using System.Collections;

namespace Google.ProtocolBuffers {
  /// <summary>
  /// Class used to represent repeat extensions in generated classes.
  /// </summary>
  public sealed class GeneratedRepeatExtension<TExtensionElement> : GeneratedExtensionBase<IList<TExtensionElement>> {
    private GeneratedRepeatExtension(FieldDescriptor field) : base(field, typeof(TExtensionElement)) {
    }

    public static GeneratedExtensionBase<IList<TExtensionElement>> CreateInstance(FieldDescriptor descriptor) {
      if (!descriptor.IsRepeated) {
        throw new ArgumentException("Must call GeneratedRepeatExtension.CreateInstance() for repeated types.");
      }
      return new GeneratedRepeatExtension<TExtensionElement>(descriptor);
    }

    /// <summary>
    /// Converts the list to the right type.
    /// TODO(jonskeet): Check where this is used, and whether we need to convert
    /// for primitive types.
    /// </summary>
    /// <param name="value"></param>
    /// <returns></returns>
    public override object FromReflectionType(object value) {
      if (Descriptor.MappedType == MappedType.Message ||
          Descriptor.MappedType == MappedType.Enum) {
        // Must convert the whole list.
        List<TExtensionElement> result = new List<TExtensionElement>();
        foreach (object element in (IEnumerable) value) {
          result.Add((TExtensionElement) SingularFromReflectionType(element));
        }
        return result;
      } else {
        return value;
      }
    }
  }
}