/Newtonsoft.Json/Modules/Converters/ExpandoObjectConverter.cs

#region License
// Copyright (c) 2007 James Newton-King
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
#endregion

#if !(NET35 || NET20 || WINDOWS_PHONE || PORTABLE)

using System;
using System.Collections.Generic;
using System.Dynamic;
using System.Globalization;
using System.Linq;
using System.Text;
using Newtonsoft.Json.Utilities;

namespace Newtonsoft.Json.Converters
{
  /// <summary>
  /// Converts an ExpandoObject to and from JSON.
  /// </summary>
  public class ExpandoObjectConverter : JsonConverter
  {
    /// <summary>
    /// Writes the JSON representation of the object.
    /// </summary>
    /// <param name="writer">The <see cref="JsonWriter"/> to write to.</param>
    /// <param name="value">The value.</param>
    /// <param name="serializer">The calling serializer.</param>
    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
      // can write is set to false
    }

    /// <summary>
    /// Reads the JSON representation of the object.
    /// </summary>
    /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>
    /// <param name="objectType">Type of the object.</param>
    /// <param name="existingValue">The existing value of object being read.</param>
    /// <param name="serializer">The calling serializer.</param>
    /// <returns>The object value.</returns>
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
      return ReadValue(reader);
    }

    private object ReadValue(JsonReader reader)
    {
      while (reader.TokenType == JsonToken.Comment)
      {
        if (!reader.Read())
          throw JsonSerializationException.Create(reader, "Unexpected end when reading ExpandoObject.");
      }

      switch (reader.TokenType)
      {
        case JsonToken.StartObject:
          return ReadObject(reader);
        case JsonToken.StartArray:
          return ReadList(reader);
        default:
          if (JsonReader.IsPrimitiveToken(reader.TokenType))
            return reader.Value;

          throw JsonSerializationException.Create(reader, "Unexpected token when converting ExpandoObject: {0}".FormatWith(CultureInfo.InvariantCulture, reader.TokenType));
      }
    }

    private object ReadList(JsonReader reader)
    {
      IList<object> list = new List<object>();

      while (reader.Read())
      {
        switch (reader.TokenType)
        {
          case JsonToken.Comment:
            break;
          default:
            object v = ReadValue(reader);

            list.Add(v);
            break;
          case JsonToken.EndArray:
            return list;
        }
      }

      throw JsonSerializationException.Create(reader, "Unexpected end when reading ExpandoObject.");
    }

    private object ReadObject(JsonReader reader)
    {
      IDictionary<string, object> expandoObject = new ExpandoObject();

      while (reader.Read())
      {
        switch (reader.TokenType)
        {
          case JsonToken.PropertyName:
            string propertyName = reader.Value.ToString();

            if (!reader.Read())
              throw JsonSerializationException.Create(reader, "Unexpected end when reading ExpandoObject.");

            object v = ReadValue(reader);

            expandoObject[propertyName] = v;
            break;
          case JsonToken.Comment:
            break;
          case JsonToken.EndObject:
            return expandoObject;
        }
      }

      throw JsonSerializationException.Create(reader, "Unexpected end when reading ExpandoObject.");
    }

    /// <summary>
    /// Determines whether this instance can convert the specified object type.
    /// </summary>
    /// <param name="objectType">Type of the object.</param>
    /// <returns>
    /// 	<c>true</c> if this instance can convert the specified object type; otherwise, <c>false</c>.
    /// </returns>
    public override bool CanConvert(Type objectType)
    {
      return (objectType == typeof (ExpandoObject));
    }

    /// <summary>
    /// Gets a value indicating whether this <see cref="JsonConverter"/> can write JSON.
    /// </summary>
    /// <value>
    /// 	<c>true</c> if this <see cref="JsonConverter"/> can write JSON; otherwise, <c>false</c>.
    /// </value>
    public override bool CanWrite
    {
      get { return false; }
    }
  }
}

#endif