context: //
  // ReplyChannelBase.cs
  //
  // Author:
  //	Atsushi Enomoto <atsushi@ximian.com>
  //
  // Copyright (C) 2006 Novell, Inc.  http://www.novell.com
  //
  // Permission is hereby granted, free of charge, to any person obtaining
  // a copy of this software and associated documentation files (the
  // "Software"), to deal in the Software without restriction, including
  // without limitation the rights to use, copy, modify, merge, publish,
  // distribute, sublicense, and/or sell copies of the Software, and to
  // permit persons to whom the Software is furnished to do so, subject to
  // the following conditions:
  // 
  // The above copyright notice and this permission notice shall be
  // included in all copies or substantial portions of the Software.
  // 
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  //
  using System;
  using System.Collections.Generic;
  using System.IO;
  using System.Net;
  using System.Net.Security;
  using System.ServiceModel;
  using System.ServiceModel.Description;
  using System.ServiceModel.Security;
  using System.Threading;
  
  namespace System.ServiceModel.Channels
  {
  	internal abstract class InternalReplyChannelBase : ReplyChannelBase
  	{
  		public InternalReplyChannelBase (ChannelListenerBase listener)
  			: base (listener)
  		{
  			local_address = new EndpointAddress (listener.Uri);
  		}
  
  		EndpointAddress local_address;
  
  		public override EndpointAddress LocalAddress {
  			get { return local_address; }
  		}
  	}
  
  	internal abstract class ReplyChannelBase : ChannelBase, IReplyChannel
  	{
  		public ReplyChannelBase (ChannelListenerBase listener)
  			: base (listener)
  		{
  			this.listener = listener;
  		}
  
  		ChannelListenerBase listener;
  
  		public ChannelListenerBase Listener {
  			get { return listener; }
  		}
  
  		public abstract EndpointAddress LocalAddress { get; }
  
  		public override T GetProperty<T> ()
  		{
  			if (typeof (T) == typeof (MessageVersion) && listener is IHasMessageEncoder)
  				return (T) (object) ((IHasMessageEncoder) listener).MessageEncoder.MessageVersion;
  			if (typeof (T) == typeof (IChannelListener))
  				return (T) (object) listener;
  			return base.GetProperty<T> ();
  		}
  
  		// FIXME: this is wrong. Implement all of them in each channel.
  		protected override void OnAbort ()
  		{
  			OnClose (TimeSpan.Zero);
  		}
  
  		protected override void OnClose (TimeSpan timeout)
  		{
  			if (CurrentAsyncThread != null)
  				if (!CancelAsync (timeout))
  					CurrentAsyncThread.Abort ();
  		}
  
  		public virtual bool CancelAsync (TimeSpan timeout)
  		{
  			// FIXME: It should wait for the actual completion.
  			return CurrentAsyncResult == null;
  			//return CurrentAsyncResult == null || CurrentAsyncResult.AsyncWaitHandle.WaitOne (timeout);
  		}
  
  		public virtual bool TryReceiveRequest ()
  		{
  			RequestContext dummy;
  			return TryReceiveRequest (DefaultReceiveTimeout, out dummy);
  		}
  
  		public abstract bool TryReceiveRequest (TimeSpan timeout, out RequestContext context);
  
  		delegate bool TryReceiveDelegate (TimeSpan timeout, out RequestContext context);
  		TryReceiveDelegate try_recv_delegate;
  
  		object async_result_lock = new object ();
  		protected Thread CurrentAsyncThread { get; private set; }
  		protected IAsyncResult CurrentAsyncResult { get; private set; }
  
  		public virtual IAsyncResult BeginTryReceiveRequest (TimeSpan timeout, AsyncCallback callback, object state)
  		{
  			if (CurrentAsyncResult != null)
  				throw new InvalidOperationException ("Another async TryReceiveRequest operation is in progress");
  			if (try_recv_delegate == null)
  				try_recv_delegate = new TryReceiveDelegate (delegate (TimeSpan tout, out RequestContext ctx) {
  					lock (async_result_lock) {
  						if (CurrentAsyncResult != null)
  							CurrentAsyncThread = Thread.CurrentThread;
  					}
  					try {
  						return TryReceiveRequest (tout, out ctx);
  					} finally {
  						lock (async_result_lock) {
  							CurrentAsyncResult = null;
  							CurrentAsyncThread = null;
  						}
  					}
  					});
  			RequestContext dummy;
  			IAsyncResult result;
  			lock (async_result_lock) {
  				result = CurrentAsyncResult = try_recv_delegate.BeginInvoke (timeout, out dummy, callback, state);
  			}
  			// Note that at this point CurrentAsyncResult can be null here if delegate has run to completion
  			return result;
  		}
  
  		public virtual bool EndTryReceiveRequest (IAsyncResult result)
  		{
  			RequestContext dummy;
  			return EndTryReceiveRequest (result, out dummy);
  		}
  
  		public virtual bool EndTryReceiveRequest (IAsyncResult result, out RequestContext context)
  		{
  			if (try_recv_delegate == null)
  				throw new InvalidOperationException ("BeginTryReceiveRequest operation has not started");
  			return try_recv_delegate.EndInvoke (out context, result);
  		}
  
  		public virtual bool WaitForRequest ()
  		{
  			return WaitForRequest (DefaultReceiveTimeout);
  		}
  
  		public abstract bool WaitForRequest (TimeSpan timeout);
  
  		Func<TimeSpan,bool> wait_delegate;
  
  		public virtual IAsyncResult BeginWaitForRequest (TimeSpan timeout, AsyncCallback callback, object state)
  		{
  			if (wait_delegate == null)
  				wait_delegate = new Func<TimeSpan,bool> (WaitForRequest);
  			return wait_delegate.BeginInvoke (timeout, callback, state);
  		}
  
  		public virtual bool EndWaitForRequest (IAsyncResult result)
  		{
  			if (wait_delegate == null)
  				throw new InvalidOperationException ("BeginWaitForRequest operation has not started");
  			return wait_delegate.EndInvoke (result);
  		}
  
  		public virtual RequestContext ReceiveRequest ()
  		{
  			return ReceiveRequest (DefaultReceiveTimeout);
  		}
  
  		public abstract RequestContext ReceiveRequest (TimeSpan timeout);
  
  		public virtual IAsyncResult BeginReceiveRequest (AsyncCallback callback, object state)
  		{
  			return BeginReceiveRequest (DefaultReceiveTimeout, callback, state);
  		}
  
  		Func<TimeSpan,RequestContext> recv_delegate;
  		public virtual IAsyncResult BeginReceiveRequest (TimeSpan timeout, AsyncCallback callback, object state)
  		{
  			if (recv_delegate == null)
  				recv_delegate = new Func<TimeSpan,RequestContext> (ReceiveRequest);
  			return recv_delegate.BeginInvoke (timeout, callback, state);
  		}
  
  		public virtual RequestContext EndReceiveRequest (IAsyncResult result)
  		{
  			if (recv_delegate == null)
  				throw new InvalidOperationException ("BeginReceiveRequest operation has not started");
  			return recv_delegate.EndInvoke (result);
  		}
  
  		Action<TimeSpan> open_delegate, close_delegate;
  
  		protected override IAsyncResult OnBeginOpen (TimeSpan timeout,
  			AsyncCallback callback, object state)
  		{
  			if (open_delegate == null)
  
gt: 				open_delegate = new Action<TimeSpan> (OnOpen);