csharp-sdk-upm/Libs/Newtonsoft.Json.AOT/JsonConverter.cs

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2021-03-31 11:22:02 +08:00
#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
using System;
using LC.Newtonsoft.Json.Utilities;
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Diagnostics.CodeAnalysis;
namespace LC.Newtonsoft.Json
{
/// <summary>
/// Converts an object to and from JSON.
/// </summary>
public abstract class 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 abstract void WriteJson(JsonWriter writer, object? value, JsonSerializer serializer);
/// <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 abstract object? ReadJson(JsonReader reader, Type objectType, object? existingValue, JsonSerializer serializer);
/// <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 abstract bool CanConvert(Type objectType);
/// <summary>
/// Gets a value indicating whether this <see cref="JsonConverter"/> can read JSON.
/// </summary>
/// <value><c>true</c> if this <see cref="JsonConverter"/> can read JSON; otherwise, <c>false</c>.</value>
public virtual bool CanRead => true;
/// <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 virtual bool CanWrite => true;
}
/// <summary>
/// Converts an object to and from JSON.
/// </summary>
/// <typeparam name="T">The object type to convert.</typeparam>
public abstract class JsonConverter<T> : 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 sealed override void WriteJson(JsonWriter writer, object? value, JsonSerializer serializer)
{
if (!(value != null ? value is T : ReflectionUtils.IsNullable(typeof(T))))
{
throw new JsonSerializationException("Converter cannot write specified value to JSON. {0} is required.".FormatWith(CultureInfo.InvariantCulture, typeof(T)));
}
WriteJson(writer, (T?)value, serializer);
}
/// <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 abstract void WriteJson(JsonWriter writer, T? value, JsonSerializer serializer);
/// <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 sealed override object? ReadJson(JsonReader reader, Type objectType, object? existingValue, JsonSerializer serializer)
{
bool existingIsNull = existingValue == null;
if (!(existingIsNull || existingValue is T))
{
throw new JsonSerializationException("Converter cannot read JSON with the specified existing value. {0} is required.".FormatWith(CultureInfo.InvariantCulture, typeof(T)));
}
return ReadJson(reader, objectType, existingIsNull ? default : (T?)existingValue, !existingIsNull, serializer);
}
/// <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. If there is no existing value then <c>null</c> will be used.</param>
/// <param name="hasExistingValue">The existing value has a value.</param>
/// <param name="serializer">The calling serializer.</param>
/// <returns>The object value.</returns>
public abstract T? ReadJson(JsonReader reader, Type objectType, T? existingValue, bool hasExistingValue, JsonSerializer serializer);
/// <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 sealed override bool CanConvert(Type objectType)
{
return typeof(T).IsAssignableFrom(objectType);
}
}
}