Templates, Inversion of Control, Factories, and so on

using System.Net;
using System.Net.Sockets;
using Pfz.Threading;

namespace Pfz.Remoting
{
	/// <summary>
	/// Listener for Tcp/IP connections and channellers.
	/// </summary>
	public sealed class TcpChannellerListener:
		ThreadSafeDisposable,
		IChannellerListener
	{
		private TcpListener _listener;
		private readonly int _bufferSizePerChannel;
		private CryptographyMode _cryptographyMode;

		/// <summary>
		/// Creates a new listener on the given address, port and using the given bufferSizePerChannel.
		/// </summary>
		public TcpChannellerListener(IPAddress localAddress, int port, int bufferSizePerChannel, bool useCryptography=false)
		{
			if (useCryptography)
				_cryptographyMode = CryptographyMode.AsServer;

			_bufferSizePerChannel = bufferSizePerChannel;
			_listener = new TcpListener(localAddress, port);
			_listener.Start();
		}

		/// <summary>
		/// Releases the internal listener.
		/// </summary>
		protected override void Dispose(bool disposing)
		{
			if (disposing)
			{
				var listener = _listener;
				if (listener != null)
				{
					_listener = null;
					listener.Stop();
				}
			}

			base.Dispose(disposing);
		}

		/// <summary>
		/// Accepts a new channeller.
		/// </summary>
		public IChanneller TryAccept()
		{
			TcpClient client;
			while(true)
			{
				try
				{
					client = _listener.AcceptTcpClient();
				}
				catch
				{
					return null;
				}

				try
				{
					return TcpChanneller.Create(client, _bufferSizePerChannel, _cryptographyMode);
				}
				catch
				{
					// if an exception happens here, probably is a problem with cryptography, but the listener is OK.
				}
			}
		}
	}
}