git_bsmd/AIS/bsmd.AIS2Service/SerialTCPReader.cs

using log4net;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace bsmd.AIS2Service
{
    internal class SerialTCPReader : IAISThread
    {
        private readonly string _host;
        private readonly uint _port;
        private readonly ConcurrentQueue<string> _inputQueue;
        private bool _stopFlag = false;

        private TcpClient tcpSocket;
        private Thread _thread;

        private static readonly ILog _log = LogManager.GetLogger(typeof(SerialTCPReader));


        public SerialTCPReader(string host, uint port, ConcurrentQueue<string> inputQueue)
        {
            _host = host; _port = port; _inputQueue = inputQueue;
        }

        private void ReadData()
        {
            try
            {
                while (!_stopFlag)
                {
                    if (this.tcpSocket == null || !this.tcpSocket.Connected) this.Connect();
                    
                    foreach(string line in ReadLines(this.tcpSocket.GetStream(), Encoding.ASCII))
                    {
                        _inputQueue.Enqueue(line);
                        if (_stopFlag) return;
                    }             
                }
            }

            catch(Exception ex)
            {
                _log.ErrorFormat("Something bad has happened: {0}", ex.Message);
                this.FatalErrorOccurred?.Invoke(this, new EventArgs());
            }
            
        }

        private void Connect()
        {            
            this.tcpSocket = new TcpClient(_host, (int)_port);            
            _log.InfoFormat("TCP stream connected ({0}:{1})", _host, _port);
        }

        private static IEnumerable<string> ReadLines(Stream source, Encoding encoding)
        {
            using(StreamReader reader = new StreamReader(source, encoding))
            {
                string line;
                
                while((line = reader.ReadLine()) != null)
                {
                    yield return line;
                }
            }
        }

        #region IAISThread implementation

        public event EventHandler FatalErrorOccurred;

        public void Start()
        {
            if (_thread != null) return; // may not run twice
            ThreadStart runReader = new ThreadStart(this.ReadData);
            _thread = new Thread(runReader);
            _thread.Start();            
        }

        public void Stop()
        {
            if(_thread == null) return;
            _stopFlag = true;
            _thread.Join();
            _thread = null;
        }

        public string Name
        {
            get { return "Serial stream reader"; }
        }

        #endregion

    }
}