UniVRM/Assets/VRM/UniJSON/Scripts/FormatterExtensions.cs

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Linq;
using System.Reflection;


namespace UniJSON
{
    public static partial class FormatterExtensions
    {
        public static ArraySegment<Byte> GetStoreBytes(this IFormatter f)
        {
            return f.GetStore().Bytes;
        }

        public static void Key(this IFormatter f, string x)
        {
            f.Key(Utf8String.From(x));
        }

        public static void Value(this IFormatter f, IEnumerable<byte> raw, int count)
        {
            f.Value(new ArraySegment<byte>(raw.Take(count).ToArray()));
        }

        public static void Value(this IFormatter f, Byte[] bytes)
        {
            f.Value(new ArraySegment<Byte>(bytes));
        }

        public static void Value(this IFormatter f, UnityEngine.Vector3 v)
        {
            //CommaCheck();
            f.BeginMap(3);
            f.Key("x"); f.Value(v.x);
            f.Key("y"); f.Value(v.y);
            f.Key("z"); f.Value(v.z);
            f.EndMap();
        }

        static MethodInfo GetMethod<T>(Expression<Func<T>> expression)
        {
            var method = typeof(FormatterExtensions).GetMethod("Serialize");
            return method.MakeGenericMethod(typeof(T));
        }

        //
        // https://stackoverflow.com/questions/238765/given-a-type-expressiontype-memberaccess-how-do-i-get-the-field-value
        //
        public static void KeyValue<T>(this IFormatter f, Expression<Func<T>> expression)
        {
            MemberExpression outerMember = (MemberExpression)expression.Body;
            var outerProp = (FieldInfo)outerMember.Member;
            MemberExpression innerMember = (MemberExpression)outerMember.Expression;
            var innerField = (FieldInfo)innerMember.Member;
            ConstantExpression ce = (ConstantExpression)innerMember.Expression;
            object innerObj = ce.Value;
            object outerObj = innerField.GetValue(innerObj);
            f.Key(outerProp.Name);
            f.Serialize(outerProp.GetValue(outerObj));
        }
    }
}