Synnefo » Pithos MS Client

#region

/* -----------------------------------------------------------------------

 * <copyright file="PithosDateTimeConverter.cs" company="GRNet">

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 * Copyright 2011-2012 GRNET S.A. All rights reserved.

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#endregion

using System;

using System.Globalization;

using Newtonsoft.Json;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Utilities;

namespace Pithos.Interfaces

{

    /// <summary>

    /// Converts a <see cref="DateTime"/> to and from a JavaScript date constructor (e.g. new Date(52231943)).

    /// </summary>

    public class PithosDateTimeConverter : DateTimeConverterBase

    {

        private DateTime _epoch = new DateTime(1970, 1, 1,0,0,0,DateTimeKind.Utc);

        /// <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)

        {

            double seconds;

            if (value is DateTime)

            {

                var dateTime = (DateTime)value;

                var utcDateTime = dateTime.ToUniversalTime();

                seconds = (utcDateTime - _epoch).TotalSeconds; ;

            }

            else if (value is DateTimeOffset)

            {

                var dateTimeOffset = (DateTimeOffset)value;

                var utcDateTimeOffset = dateTimeOffset.ToUniversalTime();

                seconds= (utcDateTimeOffset.UtcDateTime - _epoch).TotalSeconds;

            }

            else

            {

                throw new Exception("Expected date object value.");

            }

            writer.WriteValue(seconds);

        }

        /// <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 property value of the JSON that is being converted.</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)

        {

            Type t = (IsNullableType(objectType))

                         ? Nullable.GetUnderlyingType(objectType)

                         : objectType;

            if (reader.TokenType == JsonToken.Null)

            {

                if (!IsNullableType(objectType))

                    throw new Exception(String.Format("Cannot convert null value to {0}.",objectType));

                return null;

            }

            var seconds = double.Parse((string)reader.Value,CultureInfo.InvariantCulture);

            DateTime d =  _epoch.AddSeconds(seconds);

            if (t == typeof(DateTimeOffset))

                return new DateTimeOffset(d);

            return d;

        }

        public static bool IsNullableType(Type t)

        {

            if (t== null)

                throw new ArgumentNullException("t");

            return (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));

        }

    }

}