websocket-sharp/websocket-sharp/Net/ListenerAsyncResult.cs

//
// ListenerAsyncResult.cs
//	Copied from System.Net.ListenerAsyncResult.cs
//
// Authors:
//	Gonzalo Paniagua Javier (gonzalo@ximian.com)
//
// Copyright (c) 2005 Ximian, Inc (http://www.ximian.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.Net;
using System.Threading;

namespace WebSocketSharp.Net {

	class ListenerAsyncResult : IAsyncResult
	{
		#region Private Static Field

		static WaitCallback InvokeCB = new WaitCallback (InvokeCallback);

		#endregion

		#region Private Fields

		AsyncCallback       cb;
		bool                completed;
		HttpListenerContext context;
		Exception           exception;
		ListenerAsyncResult forward;
		ManualResetEvent    handle;
		object              locker;
		object              state;
		bool                synch;

		#endregion

		#region Internal Fields

		internal bool EndCalled;
		internal bool InGet;

		#endregion

		#region Constructor

		public ListenerAsyncResult (AsyncCallback cb, object state)
		{
			this.cb     = cb;
			this.state  = state;
			this.locker = new object();
		}

		#endregion

		#region Properties

		public object AsyncState {
			get {
				if (forward != null)
					return forward.AsyncState;

				return state;
			}
		}

		public WaitHandle AsyncWaitHandle {
			get {
				if (forward != null)
					return forward.AsyncWaitHandle;

				lock (locker) {
					if (handle == null)
						handle = new ManualResetEvent (completed);
				}

				return handle;
			}
		}

		public bool CompletedSynchronously {
			get {
				if (forward != null)
					return forward.CompletedSynchronously;

				return synch;
			}
		}

		public bool IsCompleted {
			get {
				if (forward != null)
					return forward.IsCompleted;

				lock (locker) {
					return completed;
				}
			}
		}

		#endregion

		#region Private Method

		static void InvokeCallback (object o)
		{
			ListenerAsyncResult ares = (ListenerAsyncResult) o;
			if (ares.forward != null) {
				InvokeCallback (ares.forward);
				return;
			}

			try {
				ares.cb (ares);
			} catch {
			}
		}

		#endregion

		#region Internal Methods

		internal void Complete (Exception exc)
		{
			if (forward != null) {
				forward.Complete (exc);
				return;
			}

			exception = exc;
			if (InGet && (exc is ObjectDisposedException))
				exception = new HttpListenerException (500, "Listener closed");

			lock (locker) {
				completed = true;
				if (handle != null)
					handle.Set ();

				if (cb != null)
					ThreadPool.UnsafeQueueUserWorkItem (InvokeCB, this);
			}
		}

		internal void Complete (HttpListenerContext context)
		{
			Complete (context, false);
		}

		internal void Complete (HttpListenerContext context, bool synch)
		{
			if (forward != null) {
				forward.Complete (context, synch);
				return;
			}

			this.synch = synch;
			this.context = context;
			lock (locker) {
				AuthenticationSchemes schemes = context.Listener.SelectAuthenticationScheme (context);
				if ((schemes == AuthenticationSchemes.Basic || context.Listener.AuthenticationSchemes == AuthenticationSchemes.Negotiate) && context.Request.Headers ["Authorization"] == null) {
					context.Response.StatusCode = 401;
					context.Response.Headers ["WWW-Authenticate"] = schemes + " realm=\"" + context.Listener.Realm + "\"";
					context.Response.OutputStream.Close ();
					IAsyncResult ares = context.Listener.BeginGetContext (cb, state);
					this.forward = (ListenerAsyncResult) ares;
					lock (forward.locker) {
						if (handle != null)
							forward.handle = handle;
					}

					ListenerAsyncResult next = forward;
					for (int i = 0; next.forward != null; i++) {
						if (i > 20)
							Complete (new HttpListenerException (400, "Too many authentication errors"));

						next = next.forward;
					}
				} else {
					completed = true;
					if (handle != null)
						handle.Set ();

					if (cb != null)
						ThreadPool.UnsafeQueueUserWorkItem (InvokeCB, this);
				}
			}
		}

		internal HttpListenerContext GetContext ()
		{
			if (forward != null)
				return forward.GetContext ();

			if (exception != null)
				throw exception;

			return context;
		}

		#endregion
	}
}