ln.bson/ln.bson/mapper/BsonMapping.cs

using System;

namespace ln.bson.mapper
{
    public abstract class BsonMapping
    {
        public Type SourceType { get; }
        
        public BsonMapping(Type sourceType)
        {
            SourceType = sourceType;
        }

        

        public abstract bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue);
        public abstract bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o);


        public class Int32 : BsonMapping
        {
            public Int32() : base(typeof(int))
            {
            }

            public override bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue)
            {
                bsonValue = new BsonInt32((int)o);
                return true;
            }

            public override bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o)
            {
                if (bsonValue is BsonInt32 bsonInt32)
                {
                    o = bsonInt32.Value;
                    return true;
                }

                o = null;
                return false;
            }
        }
        public class Int64 : BsonMapping
        {
            public Int64() : base(typeof(long))
            {
            }

            public override bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue)
            {
                bsonValue = new BsonInt64((long)o);
                return true;
            }

            public override bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o)
            {
                if (bsonValue is BsonInt64 bsonInt64)
                {
                    o = bsonInt64.Value;
                    return true;
                }

                o = null;
                return false;
            }
        }
        
        public class String : BsonMapping
        {
            public String() : base(typeof(string))
            {
            }

            public override bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue)
            {
                bsonValue = new BsonString((string)o);
                return true;
            }

            public override bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o)
            {
                if (bsonValue is BsonString bson)
                {
                    o = bson.Value;
                    return true;
                }

                o = null;
                return false;
            }
        }
        
        public class Double : BsonMapping
        {
            public Double() : base(typeof(double))
            {
            }

            public override bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue)
            {
                bsonValue = new BsonDouble((double)o);
                return true;
            }

            public override bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o)
            {
                if (bsonValue is BsonDouble bsonDouble)
                {
                    o = bsonDouble.Value;
                    return true;
                }

                o = null;
                return false;
            }
        }
        
        public class DateTime : BsonMapping
        {
            public DateTime() : base(typeof(System.DateTime))
            {
            }

            public override bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue)
            {
                bsonValue = new BsonDateTime((System.DateTime)o);
                return true;
            }

            public override bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o)
            {
                if (bsonValue is BsonDateTime bsonDateTime)
                {
                    o = bsonDateTime.Value;
                    return true;
                }

                o = null;
                return false;
            }
        }

        public class Boolean : BsonMapping
        {
            public Boolean() : base(typeof(bool))
            {
            }

            public override bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue)
            {
                bsonValue = (bool)o ? BsonBoolean.True : BsonBoolean.False;
                return true;
            }

            public override bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o)
            {
                if (bsonValue is BsonBoolean bson)
                {
                    o = bson.Value;
                    return true;
                }

                o = null;
                return false;
            }
        }

        public class Guid : BsonMapping
        {
            public Guid() : base(typeof(System.Guid))
            {
            }

            public override bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue)
            {
                bsonValue = new BsonGuid((System.Guid)o);
                return true;
            }

            public override bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o)
            {
                if (bsonValue is BsonGuid bson)
                {
                    o = bson.GuidValue;
                    return true;
                }

                o = null;
                return false;
            }
        }

        public class Binary : BsonMapping
        {
            public Binary() : base(typeof(byte[]))
            {
            }

            public override bool TryMapValue(BsonMapper mapper, object o, out BsonValue bsonValue)
            {
                bsonValue = new BsonBinary(BsonBinarySubType.Generic, (byte[])o);
                return true;
            }

            public override bool TryMapValue(BsonMapper mapper, BsonValue bsonValue, out object o)
            {
                if (bsonValue is BsonBinary bson)
                {
                    o = bson.Value;
                    return true;
                }

                o = null;
                return false;
            }
        }
    }
}