//******************************************************************************************************//  SendReadRequest.cs - Gbtc////  Copyright © 2020, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may not use this//  file except in compliance with the License. You may obtain a copy of the License at:////      http://opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  05/12/2020 - J. Ritchie Carroll//       Generated original version of source code.////****************************************************************************************************** #region [ Contributor License Agreements ] //*******************************************************************************************************////   Code based on the following project://        https://github.com/Callisto82/tftp.net//  //   Copyright © 2011, Michael Baer////******************************************************************************************************* #endregion using System.Net;using GSF.Net.TFtp.Commands; namespace GSF.Net.TFtp.Transfer.States{    internal class SendReadRequest : StateWithNetworkTimeout    {        public override void OnStateEnter()        {            base.OnStateEnter();            SendRequest(); // Send a read request to the server        }         private void SendRequest()        {            ReadRequest request = new ReadRequest(Context.Filename, Context.TransferMode, Context.ProposedOptions.ToOptionList());            SendAndRepeat(request);        }         public override void OnCommand(ITFtpCommand command, EndPoint endpoint)        {            if (command is Commands.Data || command is OptionAcknowledgement)            {                // The server acknowledged our read request.                // Fix out remote endpoint                Context.GetConnection().RemoteEndpoint = endpoint;            }             switch (command)            {                case Commands.Data _:                {                    if (Context.NegotiatedOptions == null)                        Context.FinishOptionNegotiation(TransferOptionSet.NewEmptySet());                     // Switch to the receiving state...                    ITransferState nextState = new Receiving();                    Context.SetState(nextState);                     // ...and let it handle the data packet                    nextState.OnCommand(command, endpoint);                    break;                }                                case OptionAcknowledgement optionAcknowledgement:                    // Check which options were acknowledged                    Context.FinishOptionNegotiation(new TransferOptionSet(optionAcknowledgement.Options));                     // the server acknowledged our options. Confirm the final options                    SendAndRepeat(new Acknowledgement(0));                    break;                                case Error error:                    Context.SetState(new ReceivedError(error));                    break;                 default:                    base.OnCommand(command, endpoint);                    break;            }        }         public override void OnCancel(TFtpErrorPacket reason)        {            Context.SetState(new CancelledByUser(reason));        }    }}