private object Deserialize(Type type, TFormat value)
{
if (value == null)
{
return(null);
}
return(DeserializationMethod.MakeGenericMethod(type).Invoke(Serializer, new object[] { value, default(StreamingContext) }));
}
private static DeserializationHandler <T> CreateDeserializationHandler()
{
var constructor = typeof(T).GetConstructors().Single();
// Generate a "TBuilder" type implementing IBuilder<T>.
// We'll trick the JSON serializer into deserializing a "TBuilder" then instanciate the final object by calling IBuilder<T>.Build().
// Not the cleanest way to do it, but might be one of the less "allocatey" ?
string assemblyName = $"Serialization.Json.Builders.{typeof(T).Name}";
var assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(new AssemblyName(assemblyName), AssemblyBuilderAccess.RunAndCollect);
var moduleBuilder = assemblyBuilder.DefineDynamicModule(assemblyName);
var typeBuilder = moduleBuilder.DefineType(assemblyName + "Builder", TypeAttributes.Public | TypeAttributes.Sealed, typeof(ValueType));
var properties = Array.ConvertAll
(
constructor.GetParameters(),
parameter =>
{
string propertyName = char.ToUpperInvariant(parameter.Name[0]) + parameter.Name.Substring(1);
// Fields ought to be enough, but System.Text.Json seems to require properties 😥
var field = typeBuilder.DefineField($"_{parameter.Name}", parameter.ParameterType, FieldAttributes.Public);
var getMethodBuilder = typeBuilder.DefineMethod($"get_{propertyName}", MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.SpecialName, CallingConventions.HasThis, parameter.ParameterType, Type.EmptyTypes);
{
var ilGenerator = getMethodBuilder.GetILGenerator();
ilGenerator.Emit(OpCodes.Ldarg_0);
ilGenerator.Emit(OpCodes.Ldfld, field);
ilGenerator.Emit(OpCodes.Ret);
}
var setMethodBuilder = typeBuilder.DefineMethod($"set_{propertyName}", MethodAttributes.Public | MethodAttributes.HideBySig | MethodAttributes.SpecialName, CallingConventions.HasThis, typeof(void), new[] { parameter.ParameterType });
{
var ilGenerator = setMethodBuilder.GetILGenerator();
ilGenerator.Emit(OpCodes.Ldarg_0);
ilGenerator.Emit(OpCodes.Ldarg_1);
ilGenerator.Emit(OpCodes.Stfld, field);
ilGenerator.Emit(OpCodes.Ret);
}
var property = typeBuilder.DefineProperty(propertyName, PropertyAttributes.None, parameter.ParameterType, Type.EmptyTypes);
property.SetGetMethod(getMethodBuilder);
property.SetSetMethod(setMethodBuilder);
return(property);
}
);
var methodBuilder = typeBuilder.DefineMethod("Build", MethodAttributes.Public | MethodAttributes.NewSlot | MethodAttributes.Virtual | MethodAttributes.HideBySig | MethodAttributes.Final, CallingConventions.HasThis, typeof(T), Type.EmptyTypes);
{
var ilGenerator = methodBuilder.GetILGenerator();
foreach (var property in properties)
{
ilGenerator.Emit(OpCodes.Ldarg_0);
ilGenerator.Emit(OpCodes.Call, property.GetMethod);
}
ilGenerator.Emit(OpCodes.Newobj, constructor);
ilGenerator.Emit(OpCodes.Ret);
}
typeBuilder.AddInterfaceImplementation(typeof(IBuilder <T>));
var builderType = typeBuilder.CreateTypeInfo();
return((DeserializationHandler <T>)DeserializationMethod.MakeGenericMethod(new[] { typeof(T), builderType })
.CreateDelegate(typeof(DeserializationHandler <T>), ImmutableJsonConverter.Instance));
}