ZContext.cs

using System;
using System.Text;
using System.Threading;

using ZeroMQ.lib;

namespace ZeroMQ
{
	/// <summary>
	/// Creates <see cref="ZSocket"/> instances within a process boundary.
	/// </summary>
	public sealed class ZContext : IDisposable
	{
		static Encoding _encoding = System.Text.Encoding.UTF8;

		/// <summary>
		/// Gets and protected sets the default Encoding.
		/// Note: Do not set the Encoding after ZContext.Create.
		/// </summary>
		public static Encoding Encoding
		{
			get { return _encoding; }
		}

		private static readonly object SyncObject = new object();

		private static ZContext _current;

		public static ZContext Current 
		{
			get 
			{
				if (_current == null)
				{
					// INFO: This is the ZContext who is the one, running this program.
					lock (SyncObject)
					{
						if (_current == null)
						{
							_current = new ZContext();
						}
					}
				}
				return _current;
			}
		}

		/// <summary>
		/// Create a <see cref="ZContext"/> instance.
		/// </summary>
		/// <returns><see cref="ZContext"/></returns>
		public ZContext()
		{
			_contextPtr = zmq.ctx_new();

			if (_contextPtr == IntPtr.Zero)
			{
				throw new InvalidProgramException("zmq_ctx_new");
			}
		}

		/// <summary>
		/// Create a <see cref="ZContext"/> instance.
		/// </summary>
		/// <returns><see cref="ZContext"/></returns>
		public static ZContext Create()
		{
			return new ZContext();
		}

		~ZContext()
		{
			Dispose(false);
		}

		private IntPtr _contextPtr;

		/// <summary>
		/// Gets a handle to the native ZeroMQ context.
		/// </summary>
		public IntPtr ContextPtr
		{
			get { return _contextPtr; }
		}

		public static bool Has(string capability)
		{
			using (var capabilityPtr = DispoIntPtr.AllocString(capability))
			{
				if (0 < zmq.has(capabilityPtr))
				{
					return true;
				}
			}
			return false;
		}

		public static void Proxy(ZSocket frontend, ZSocket backend)
		{
			Proxy(frontend, backend, null);
		}

		public static bool Proxy(ZSocket frontend, ZSocket backend, out ZError error)
		{
			return Proxy(frontend, backend, null, out error);
		}

		public static void Proxy(ZSocket frontend, ZSocket backend, ZSocket capture)
		{
			ZError error;
			if (!Proxy(frontend, backend, capture, out error))
			{
				if (error == ZError.ETERM)
				{
					return;	// Interrupted
				}
				throw new ZException(error);
			}
		}

		public static bool Proxy(ZSocket frontend, ZSocket backend, ZSocket capture, out ZError error)
		{
			error = ZError.None;

			while (-1 == zmq.proxy(frontend.SocketPtr, backend.SocketPtr, capture == null ? IntPtr.Zero : capture.SocketPtr))
			{
				error = ZError.GetLastErr();

				if (error == ZError.EINTR)
				{
					error = default(ZError);
					continue;
				}
				return false;
			}
			return true;
		}

		public static void ProxySteerable(ZSocket frontend, ZSocket backend, ZSocket control)
		{
			ProxySteerable(frontend, backend, null, control);
		}

		public static bool ProxySteerable(ZSocket frontend, ZSocket backend, ZSocket control, out ZError error)
		{
			return ProxySteerable(frontend, backend, null, control, out error);
		}

		public static void ProxySteerable(ZSocket frontend, ZSocket backend, ZSocket capture, ZSocket control)
		{
			ZError error;
			if (!ProxySteerable(frontend, backend, capture, control, out error))
			{
				if (error == ZError.ETERM)
				{
					return;	// Interrupted
				}
				throw new ZException(error);
			}
		}

		public static bool ProxySteerable(ZSocket frontend, ZSocket backend, ZSocket capture, ZSocket control, out ZError error)
		{
			error = ZError.None;

			while (-1 == zmq.proxy_steerable(frontend.SocketPtr, backend.SocketPtr, capture == null ? IntPtr.Zero : capture.SocketPtr, control == null ? IntPtr.Zero : control.SocketPtr))
			{
				error = ZError.GetLastErr();

				if (error == ZError.EINTR)
				{
					error = default(ZError);
					continue;
				}
				return false;
			}
			return true;
		}

		public void SetOption(ZContextOption option, int optionValue)
		{
			EnsureNotDisposed();

			int rc = zmq.ctx_set(_contextPtr, (Int32)option, optionValue);
			if (rc == -1)
			{
				var error = ZError.GetLastErr();

				if (error == ZError.EINVAL)
				{
					throw new ArgumentOutOfRangeException(
						string.Format("The requested option optionName \"{0}\" is invalid.", option));
				}
				throw new ZException(error);
			}
		}

		public int GetOption(ZContextOption option)
		{
			EnsureNotDisposed();

			int rc = zmq.ctx_get(_contextPtr, (Int32)option);
			if (rc == -1)
			{
				var error = ZError.GetLastErr();

				if (error == ZError.EINVAL)
				{
					throw new ArgumentOutOfRangeException(
						string.Format("The requested option optionName \"{0}\" is invalid.", option));
				}
				throw new ZException(error);
			}
			return rc;
		}

		/// <summary>
		/// Gets or sets the size of the thread pool for the current context (default = 1).
		/// </summary>
		public int ThreadPoolSize
		{
			get { return GetOption(ZContextOption.IO_THREADS); }
			set { SetOption(ZContextOption.IO_THREADS, value); }
		}

		/// <summary>
		/// Gets or sets the maximum number of sockets for the current context (default = 1024).
		/// </summary>
		public int MaxSockets
		{
			get { return GetOption(ZContextOption.MAX_SOCKETS); }
			set { SetOption(ZContextOption.MAX_SOCKETS, value); }
		}

		/// <summary>
		/// Gets or sets the supported socket protocol(s) when using TCP transports. (Default = <see cref="ProtocolType.Ipv4Only"/>).
		/// </summary>
		public bool IPv6Enabled
		{
			get { return GetOption(ZContextOption.IPV6) == 1; }
			set { SetOption(ZContextOption.IPV6, value ? 1 : 0); }
		}

		/// <summary>
		/// Shutdown the ZeroMQ context.
		/// </summary>
		public void Shutdown()
		{
			ZError error;
			if (!Shutdown(out error))
			{
				throw new ZException(error);
			}
		}

		/// <summary>
		/// Shutdown the ZeroMQ context.
		/// </summary>
		public bool Shutdown(out ZError error)
		{
			error = default(ZError);

			if (_contextPtr == IntPtr.Zero)
				return true;

			while (-1 == zmq.ctx_shutdown(_contextPtr))
			{
				error = ZError.GetLastErr();

				if (error == ZError.EINTR)
				{
					error = default(ZError);
					continue;
				}

				// Maybe ZError.EFAULT

				return false;
			}

			// don't _contextPtr = IntPtr.Zero;
			return true;
		}

		/// <summary>
		/// Terminate the ZeroMQ context.
		/// </summary>
		public void Terminate()
		{
			ZError error;
			if (!Terminate(out error))
			{
				throw new ZException(error);
			}
		}

		/// <summary>
		/// Terminate the ZeroMQ context.
		/// </summary>
		public bool Terminate(out ZError error)
		{
			error = ZError.None;
			if (_contextPtr == IntPtr.Zero)
				return true;

			while (-1 == zmq.ctx_term(_contextPtr))
			{
				error = ZError.GetLastErr();

				if (error == ZError.EINTR)
				{
					error = default(ZError);
					continue;
				}

				// Maybe ZError.EFAULT

				return false;
			}

			_contextPtr = IntPtr.Zero;
			return true;
		}

		public void Dispose()
		{
			GC.SuppressFinalize(this);
			Dispose(true);
		}

		void Dispose(bool disposing)
		{
			if (disposing)
			{
				ZError error;
				Terminate(out error);
			}
		}

		private void EnsureNotDisposed()
		{
			if (_contextPtr == IntPtr.Zero)
			{
				throw new ObjectDisposedException(GetType().FullName);
			}
		}
	}
}