RobustToolbox/Robust.Shared/Serialization/RobustSerializer.MappedStringSerializer.MsgServerHandshake.cs

using System;
using JetBrains.Annotations;
using Lidgren.Network;
using Robust.Shared.Interfaces.Network;
using Robust.Shared.Network;

namespace Robust.Shared.Serialization
{

    public partial class RobustSerializer
    {

        public partial class MappedStringSerializer
        {

            /// <summary>
            /// The server part of the string-exchange handshake. Sent as the
            /// first message in the handshake. Tells the client the hash of
            /// the current string mapping, so the client can check if it has
            /// a local copy.
            /// </summary>
            /// <seealso cref="NetworkInitialize"/>
            [UsedImplicitly]
            private class MsgServerHandshake : NetMessage
            {

                public MsgServerHandshake(INetChannel ch)
                    : base($"{nameof(RobustSerializer)}.{nameof(MappedStringSerializer)}.{nameof(MsgServerHandshake)}", MsgGroups.Core)
                {
                }

                /// <value>
                /// The hash of the current string mapping held by the server.
                /// </value>
                public byte[]? Hash { get; set; }

                public override void ReadFromBuffer(NetIncomingMessage buffer)
                {
                    var len = buffer.ReadVariableInt32();
                    if (len > 64)
                    {
                        throw new InvalidOperationException("Hash too long.");
                    }

                    Hash = buffer.ReadBytes(len);
                }

                public override void WriteToBuffer(NetOutgoingMessage buffer)
                {
                    if (Hash == null)
                    {
                        throw new InvalidOperationException("Package has not been specified.");
                    }

                    buffer.WriteVariableInt32(Hash.Length);
                    buffer.Write(Hash);
                }

            }

        }

    }

}