2009-07-11 Michael Barker <mike@middlesoft.co.uk>

[mono.git] / mcs / class / System.Web / System.Web / HttpApplication.cs

//
// System.Web.HttpApplication.cs 
//
// Author:
//      Miguel de Icaza (miguel@novell.com)
//      Gonzalo Paniagua (gonzalo@ximian.com)
//    
//
// Copyright (C) 2005 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.
//
// The Application Processing Pipeline.
// 
//     The Http application pipeline implemented in this file is a
//     beautiful thing.  The application pipeline invokes a number of
//     hooks at various stages of the processing of a request.  These
//     hooks can be either synchronous or can be asynchronous.
//     
//     The pipeline must ensure that every step is completed before
//     moving to the next step.  A trivial thing for synchronous
//     hooks, but asynchronous hooks introduce an extra layer of
//     complexity: when the hook is invoked, the thread must
//     relinquish its control so that the thread can be reused in
//     another operation while waiting.
//
//     To implement this functionality we used C# iterators manually;
//     we drive the pipeline by executing the various hooks from the
//     `RunHooks' routine which is an enumerator that will yield the
//     value `false' if execution must proceed or `true' if execution
//     must be stopped.
//
//     By yielding values we can suspend execution of RunHooks.
//
//     Special attention must be given to `in_begin' and `must_yield'
//     variables.  These are used in the case that an async hook
//     completes synchronously as its important to not yield in that
//     case or we would hang.
//    
//     Many of Mono modules used to be declared async, but they would
//     actually be completely synchronous, this might resurface in the
//     future with other modules.
//
// TODO:
//    Events Disposed
//

using System.IO;
using System.Collections;
using System.ComponentModel;
using System.Configuration;
using System.Diagnostics;
using System.Globalization;
using System.Reflection;
using System.Security.Permissions;
using System.Security.Principal;
using System.Threading;
using System.Web.Caching;
using System.Web.Configuration;
using System.Web.SessionState;
using System.Web.UI;

#if TARGET_J2EE
using Mainsoft.Web;
#endif
        
namespace System.Web {

        // CAS
        [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
        [AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
        // attributes
        [ToolboxItem(false)]
        public class HttpApplication : IHttpAsyncHandler, IHttpHandler, IComponent, IDisposable
        {
                static readonly object disposedEvent = new object ();
                static readonly object errorEvent = new object ();
                
                // we do this static rather than per HttpApplication because
                // mono's perfcounters use the counter instance parameter for
                // the process to access shared memory.
                internal static PerformanceCounter requests_total_counter = new PerformanceCounter ("ASP.NET", "Requests Total");
                
                internal static readonly string [] BinDirs = {"Bin", "bin"};
                object this_lock = new object();
                
                HttpContext context;
                HttpSessionState session;
                ISite isite;

                // The source, and the exposed API (cache).
                HttpModuleCollection modcoll;

                string assemblyLocation;

                //
                // The factory for the handler currently running.
                //
                IHttpHandlerFactory factory;

                //
                // Whether the thread culture is to be auto-set.
                // Used only in the 2.0 profile, always false for 1.x
                //
                bool autoCulture;
                bool autoUICulture;
                
                //
                // Whether the pipeline should be stopped
                //
                bool stop_processing;

                //
                // See https://bugzilla.novell.com/show_bug.cgi?id=381971
                //
                bool in_application_start;
                
                //
                // The Pipeline
                //
                IEnumerator pipeline;

                // To flag when we are done processing a request from BeginProcessRequest.
                ManualResetEvent done;

                // The current IAsyncResult for the running async request handler in the pipeline
                AsyncRequestState begin_iar;

                // Tracks the current AsyncInvocation being dispatched
                AsyncInvoker current_ai;

                EventHandlerList events;
                EventHandlerList nonApplicationEvents = new EventHandlerList ();
                
                // Culture and IPrincipal
                CultureInfo app_culture;
                CultureInfo appui_culture;
                CultureInfo prev_app_culture;
                CultureInfo prev_appui_culture;
                IPrincipal prev_user;

                static string binDirectory;
                
#if NET_2_0
#if TARGET_J2EE
                const string initialization_exception_key = "System.Web.HttpApplication.initialization_exception";
                static Exception initialization_exception {
                        get { return (Exception) AppDomain.CurrentDomain.GetData (initialization_exception_key); }
                        set { AppDomain.CurrentDomain.SetData (initialization_exception_key, value); }
                }
#else
                static Exception initialization_exception;
#endif
                bool removeConfigurationFromCache;
#endif
                bool fullInitComplete = false;
                
                //
                // These are used to detect the case where the EndXXX method is invoked
                // from within the BeginXXXX delegate, so we detect whether we kick the
                // pipeline from here, or from the the RunHook routine
                //
                bool must_yield;
                bool in_begin;

                public virtual event EventHandler Disposed {
                        add { nonApplicationEvents.AddHandler (disposedEvent, value); }
                        remove { nonApplicationEvents.RemoveHandler (disposedEvent, value); }
                }
                
                public virtual event EventHandler Error {
                        add { nonApplicationEvents.AddHandler (errorEvent, value); }
                        remove { nonApplicationEvents.RemoveHandler (errorEvent, value); }
                }

                public HttpApplication ()
                {
                        done = new ManualResetEvent (false);
                }
                
                internal void InitOnce (bool full_init)
                {
                        lock (this_lock) {
                                if (modcoll != null)
                                        return;
                                
#if NET_2_0
                                HttpModulesSection modules;
                                modules = (HttpModulesSection) WebConfigurationManager.GetWebApplicationSection ("system.web/httpModules");
#else
                                ModulesConfiguration modules;

                                modules = (ModulesConfiguration) HttpContext.GetAppConfig ("system.web/httpModules");
#endif

                                HttpContext saved = HttpContext.Current;
                                HttpContext.Current = new HttpContext (new System.Web.Hosting.SimpleWorkerRequest ("", "", new StringWriter()));
                                modcoll = modules.LoadModules (this);
                                HttpContext.Current = saved;

                                if (full_init) {
                                        HttpApplicationFactory.AttachEvents (this);
                                        Init ();
                                        fullInitComplete = true;
                                }
                        }
                }

                internal bool InApplicationStart {
                        get { return in_application_start; }
                        set { in_application_start = value; }
                }
                
                internal string AssemblyLocation {
                        get {
                                if (assemblyLocation == null)
                                        assemblyLocation = GetType ().Assembly.Location;
                                return assemblyLocation;
                        }
                }

#if NET_2_0
                internal static Exception InitializationException {
                        get { return initialization_exception; }
                }
#endif

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public HttpApplicationState Application {
                        get {
                                return HttpApplicationFactory.ApplicationState;
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public HttpContext Context {
                        get {
                                return context;
                        }
                }
                                         
                protected EventHandlerList Events {
                        get {
                                if (events == null)
                                        events = new EventHandlerList ();

                                return events;
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public HttpModuleCollection Modules {
                        [AspNetHostingPermission (SecurityAction.Demand, Level = AspNetHostingPermissionLevel.High)]
                        get {
                                lock (this_lock) {
                                        if (modcoll == null)
                                                modcoll = new HttpModuleCollection ();
                                }
                                
                                return modcoll;
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public HttpRequest Request {
                        get {
                                if (context == null)
                                        throw new HttpException (Locale.GetText ("No context is available."));

                                if (false == HttpApplicationFactory.ContextAvailable)
                                        throw new HttpException (Locale.GetText ("Request is not available in this context."));

                                return context.Request;
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public HttpResponse Response {
                        get {
                                if (context == null)
                                        throw new HttpException (Locale.GetText ("No context is available."));

                                if (false == HttpApplicationFactory.ContextAvailable)
                                        throw new HttpException (Locale.GetText ("Response is not available in this context."));

                                return context.Response;
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public HttpServerUtility Server {
                        get {
                                if (context != null)
                                        return context.Server;

                                //
                                // This is so we can get the Server and call a few methods
                                // which are not context sensitive, see HttpServerUtilityTest
                                //
                                return new HttpServerUtility ((HttpContext) null);
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public HttpSessionState Session {
                        get {
                                // Only used for Session_End
                                if (session != null)
                                        return session;

                                if (context == null)
                                        throw new HttpException (Locale.GetText ("No context is available."));

                                HttpSessionState ret = context.Session;
                                if (ret == null)
                                        throw new HttpException (Locale.GetText ("Session state is not available in the context."));
                                
                                return ret;
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
#if NET_2_0
                public ISite Site {
#else
                public virtual ISite Site {
#endif
                        get {
                                return isite;
                        }

                        set {
                                isite = value;
                        }
                }

                [Browsable (false)]
                [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
                public IPrincipal User {
                        get {
                                if (context == null)
                                        throw new HttpException (Locale.GetText ("No context is available."));
                                if (context.User == null)
                                        throw new HttpException (Locale.GetText ("No currently authenticated user."));
                                
                                return context.User;
                        }
                }
                
                static object PreSendRequestHeadersEvent = new object ();
                public event EventHandler PreSendRequestHeaders
                {
                        add { AddEventHandler (PreSendRequestHeadersEvent, value); }
                        remove { RemoveEventHandler (PreSendRequestHeadersEvent, value); }
                }
                
                internal void TriggerPreSendRequestHeaders ()
                {
                        EventHandler handler = Events [PreSendRequestHeadersEvent] as EventHandler;
                        if (handler != null)
                                handler (this, EventArgs.Empty);
                }

                static object PreSendRequestContentEvent = new object ();
                public event EventHandler PreSendRequestContent
                {
                        add { AddEventHandler (PreSendRequestContentEvent, value); }
                        remove { RemoveEventHandler (PreSendRequestContentEvent, value); }
                }
                
                internal void TriggerPreSendRequestContent ()
                {
                        EventHandler handler = Events [PreSendRequestContentEvent] as EventHandler;
                        if (handler != null)
                                handler (this, EventArgs.Empty);
                }

                static object AcquireRequestStateEvent = new object ();
                public event EventHandler AcquireRequestState
                {
                        add { AddEventHandler (AcquireRequestStateEvent, value); }
                        remove { RemoveEventHandler (AcquireRequestStateEvent, value); }
                }
                
                public void AddOnAcquireRequestStateAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        AcquireRequestState += new EventHandler (invoker.Invoke);
                }

                static object AuthenticateRequestEvent = new object ();
                public event EventHandler AuthenticateRequest
                {
                        add { AddEventHandler (AuthenticateRequestEvent, value); }
                        remove { RemoveEventHandler (AuthenticateRequestEvent, value); }
                }
                
                public void AddOnAuthenticateRequestAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        AuthenticateRequest += new EventHandler (invoker.Invoke);
                }

                static object AuthorizeRequestEvent = new object ();
                public event EventHandler AuthorizeRequest
                {
                        add { AddEventHandler (AuthorizeRequestEvent, value); }
                        remove { RemoveEventHandler (AuthorizeRequestEvent, value); }
                }
                
                public void AddOnAuthorizeRequestAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        AuthorizeRequest += new EventHandler (invoker.Invoke);
                }

                static object BeginRequestEvent = new object ();
                public event EventHandler BeginRequest          
                {
                        add {
                                // See https://bugzilla.novell.com/show_bug.cgi?id=381971
                                if (InApplicationStart)
                                        return;
                                AddEventHandler (BeginRequestEvent, value);
                        }
                        remove {
                                if (InApplicationStart)
                                        return;
                                RemoveEventHandler (BeginRequestEvent, value);
                        }
                }
                
                public void AddOnBeginRequestAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        BeginRequest += new EventHandler (invoker.Invoke);
                }

                static object EndRequestEvent = new object ();
                public event EventHandler EndRequest
                {
                        add {
                                // See https://bugzilla.novell.com/show_bug.cgi?id=381971
                                if (InApplicationStart)
                                        return;
                                AddEventHandler (EndRequestEvent, value);
                        }
                        remove {
                                if (InApplicationStart)
                                        return;
                                RemoveEventHandler (EndRequestEvent, value);
                        }
                }
                
                public void AddOnEndRequestAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        EndRequest += new EventHandler (invoker.Invoke);
                }

                static object PostRequestHandlerExecuteEvent = new object ();
                public event EventHandler PostRequestHandlerExecute
                {
                        add { AddEventHandler (PostRequestHandlerExecuteEvent, value); }
                        remove { RemoveEventHandler (PostRequestHandlerExecuteEvent, value); }
                }
                
                public void AddOnPostRequestHandlerExecuteAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        PostRequestHandlerExecute += new EventHandler (invoker.Invoke);
                }

                static object PreRequestHandlerExecuteEvent = new object ();
                public event EventHandler PreRequestHandlerExecute
                {
                        add { AddEventHandler (PreRequestHandlerExecuteEvent, value); }
                        remove { RemoveEventHandler (PreRequestHandlerExecuteEvent, value); }
                }
                
                public void AddOnPreRequestHandlerExecuteAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        PreRequestHandlerExecute += new EventHandler (invoker.Invoke);
                }

                static object ReleaseRequestStateEvent = new object ();
                public event EventHandler ReleaseRequestState
                {
                        add { AddEventHandler (ReleaseRequestStateEvent, value); }
                        remove { RemoveEventHandler (ReleaseRequestStateEvent, value); }
                }
                
                public void AddOnReleaseRequestStateAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        ReleaseRequestState += new EventHandler (invoker.Invoke);
                }

                static object ResolveRequestCacheEvent = new object ();
                public event EventHandler ResolveRequestCache
                {
                        add { AddEventHandler (ResolveRequestCacheEvent, value); }
                        remove { RemoveEventHandler (ResolveRequestCacheEvent, value); }
                }
                
                public void AddOnResolveRequestCacheAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        ResolveRequestCache += new EventHandler (invoker.Invoke);
                }

                static object UpdateRequestCacheEvent = new object ();
                public event EventHandler UpdateRequestCache
                {
                        add { AddEventHandler (UpdateRequestCacheEvent, value); }
                        remove { RemoveEventHandler (UpdateRequestCacheEvent, value); }
                }
                
                public void AddOnUpdateRequestCacheAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh);
                        UpdateRequestCache += new EventHandler (invoker.Invoke);
                }

#if NET_2_0
                static object PostAuthenticateRequestEvent = new object ();
                public event EventHandler PostAuthenticateRequest
                {
                        add { AddEventHandler (PostAuthenticateRequestEvent, value); }
                        remove { RemoveEventHandler (PostAuthenticateRequestEvent, value); }
                }
                
                public void AddOnPostAuthenticateRequestAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnPostAuthenticateRequestAsync (bh, eh, null);
                }
                        
                public void AddOnPostAuthenticateRequestAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PostAuthenticateRequest += new EventHandler (invoker.Invoke);
                }

                static object PostAuthorizeRequestEvent = new object ();
                public event EventHandler PostAuthorizeRequest
                {
                        add { AddEventHandler (PostAuthorizeRequestEvent, value); }
                        remove { RemoveEventHandler (PostAuthorizeRequestEvent, value); }
                }
                
                public void AddOnPostAuthorizeRequestAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnPostAuthorizeRequestAsync (bh, eh, null);
                }
                
                public void AddOnPostAuthorizeRequestAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PostAuthorizeRequest += new EventHandler (invoker.Invoke);
                }
                
                static object PostResolveRequestCacheEvent = new object ();
                public event EventHandler PostResolveRequestCache
                {
                        add { AddEventHandler (PostResolveRequestCacheEvent, value); }
                        remove { RemoveEventHandler (PostResolveRequestCacheEvent, value); }
                }
                
                public void AddOnPostResolveRequestCacheAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnPostResolveRequestCacheAsync (bh, eh, null);
                }
                
                public void AddOnPostResolveRequestCacheAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PostResolveRequestCache += new EventHandler (invoker.Invoke);
                }

                static object PostMapRequestHandlerEvent = new object ();
                public event EventHandler PostMapRequestHandler
                {
                        add { AddEventHandler (PostMapRequestHandlerEvent, value); }
                        remove { RemoveEventHandler (PostMapRequestHandlerEvent, value); }
                }
                
                public void AddOnPostMapRequestHandlerAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnPostMapRequestHandlerAsync (bh, eh, null);
                }
                
                public void AddOnPostMapRequestHandlerAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PostMapRequestHandler += new EventHandler (invoker.Invoke);
                }

                static object PostAcquireRequestStateEvent = new object ();
                public event EventHandler PostAcquireRequestState
                {
                        add { AddEventHandler (PostAcquireRequestStateEvent, value); }
                        remove { RemoveEventHandler (PostAcquireRequestStateEvent, value); }
                }
                
                public void AddOnPostAcquireRequestStateAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnPostAcquireRequestStateAsync (bh, eh, null);
                }
                
                public void AddOnPostAcquireRequestStateAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PostAcquireRequestState += new EventHandler (invoker.Invoke);
                }

                static object PostReleaseRequestStateEvent = new object ();
                public event EventHandler PostReleaseRequestState
                {
                        add { AddEventHandler (PostReleaseRequestStateEvent, value); }
                        remove { RemoveEventHandler (PostReleaseRequestStateEvent, value); }
                }
                
                public void AddOnPostReleaseRequestStateAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnPostReleaseRequestStateAsync (bh, eh, null);
                }
                
                public void AddOnPostReleaseRequestStateAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PostReleaseRequestState += new EventHandler (invoker.Invoke);
                }

                static object PostUpdateRequestCacheEvent = new object ();
                public event EventHandler PostUpdateRequestCache
                {
                        add { AddEventHandler (PostUpdateRequestCacheEvent, value); }
                        remove { RemoveEventHandler (PostUpdateRequestCacheEvent, value); }
                }
                
                public void AddOnPostUpdateRequestCacheAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnPostUpdateRequestCacheAsync (bh, eh, null);
                }
                
                public void AddOnPostUpdateRequestCacheAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PostUpdateRequestCache += new EventHandler (invoker.Invoke);
                }

                //
                // The new overloads that take a data parameter
                //
                public void AddOnAcquireRequestStateAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        AcquireRequestState += new EventHandler (invoker.Invoke);
                }

                public void AddOnAuthenticateRequestAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        AuthenticateRequest += new EventHandler (invoker.Invoke);
                }

                public void AddOnAuthorizeRequestAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        AuthorizeRequest += new EventHandler (invoker.Invoke);
                }

                public void AddOnBeginRequestAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        BeginRequest += new EventHandler (invoker.Invoke);
                }

                public void AddOnEndRequestAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        EndRequest += new EventHandler (invoker.Invoke);
                }
                
                public void AddOnPostRequestHandlerExecuteAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PostRequestHandlerExecute += new EventHandler (invoker.Invoke);
                }

                public void AddOnPreRequestHandlerExecuteAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        PreRequestHandlerExecute += new EventHandler (invoker.Invoke);
                }

                public void AddOnReleaseRequestStateAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        ReleaseRequestState += new EventHandler (invoker.Invoke);
                }

                public void AddOnResolveRequestCacheAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        ResolveRequestCache += new EventHandler (invoker.Invoke);
                }

                public void AddOnUpdateRequestCacheAsync (BeginEventHandler bh, EndEventHandler eh, object data)
                {
                        AsyncInvoker invoker = new AsyncInvoker (bh, eh, data);
                        UpdateRequestCache += new EventHandler (invoker.Invoke);
                }

                // Added in 2.0 SP1
                // They are for use with the IIS7 integrated mode, but have been added for
                // compatibility
                static object LogRequestEvent = new object ();
                public event EventHandler LogRequest
                {
                        add { AddEventHandler (LogRequestEvent, value); }
                        remove { RemoveEventHandler (LogRequestEvent, value); }
                }
                
                public void AddOnLogRequestAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnLogRequestAsync (bh, eh, null);
                }
                
                public void AddOnLogRequestAsync (BeginEventHandler beginHandler, EndEventHandler endHandler, object state)
                {
                        AsyncInvoker invoker = new AsyncInvoker (beginHandler, endHandler, state);
                        LogRequest += new EventHandler (invoker.Invoke);
                }

                static object MapRequestHandlerEvent = new object ();
                public event EventHandler MapRequestHandler
                {
                        add { AddEventHandler (MapRequestHandlerEvent, value); }
                        remove { RemoveEventHandler (MapRequestHandlerEvent, value); }
                }
                
                public void AddOnMapRequestHandlerAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnMapRequestHandlerAsync (bh, eh, null);
                }

                public void AddOnMapRequestHandlerAsync (BeginEventHandler beginHandler, EndEventHandler endHandler, object state)
                {
                        AsyncInvoker invoker = new AsyncInvoker (beginHandler, endHandler, state);
                        MapRequestHandler += new EventHandler (invoker.Invoke);
                }

                static object PostLogRequestEvent = new object ();
                public event EventHandler PostLogRequest
                {
                        add { AddEventHandler (PostLogRequestEvent, value); }
                        remove { RemoveEventHandler (PostLogRequestEvent, value); }
                }
                
                public void AddOnPostLogRequestAsync (BeginEventHandler bh, EndEventHandler eh)
                {
                        AddOnPostLogRequestAsync (bh, eh, null);
                }

                public void AddOnPostLogRequestAsync (BeginEventHandler beginHandler, EndEventHandler endHandler, object state)
                {
                        AsyncInvoker invoker = new AsyncInvoker (beginHandler, endHandler, state);
                        PostLogRequest += new EventHandler (invoker.Invoke);
                }

#endif
                
                internal event EventHandler DefaultAuthentication;

                void AddEventHandler (object key, EventHandler handler)
                {
                        if (fullInitComplete)
                                return;

                        Events.AddHandler (key, handler);
                }

                void RemoveEventHandler (object key, EventHandler handler)
                {
                        if (fullInitComplete)
                                return;

                        Events.RemoveHandler (key, handler);
                }
                
                //
                // Bypass all the event on the Http pipeline and go directly to EndRequest
                //
                public void CompleteRequest ()
                {
                        stop_processing = true;
                }

                internal bool RequestCompleted {
                        set { stop_processing = value; }
                }

                internal void DisposeInternal ()
                {
                        Dispose ();
                        lock (this_lock) {
                                if (modcoll != null) {
                                        for (int i = modcoll.Count - 1; i >= 0; i--) {
                                                modcoll.Get (i).Dispose ();
                                        }
                                        modcoll = null;
                                }
                        }

                        EventHandler eh = nonApplicationEvents [disposedEvent] as EventHandler;
                        if (eh != null)
                                eh (this, EventArgs.Empty);
                        
                        done.Close ();
                        done = null;
                }
                
                public virtual void Dispose ()
                {
                }

                public virtual string GetVaryByCustomString (HttpContext context, string custom)
                {
                        if (custom == null) // Sigh
                                throw new NullReferenceException ();

                        if (0 == String.Compare (custom, "browser", true, CultureInfo.InvariantCulture))
                                return context.Request.Browser.Type;

                        return null;
                }

                //
                // If we catch an error, queue this error
                //
                void ProcessError (Exception e)
                {
                        bool first = context.Error == null;
                        context.AddError (e);
                        if (first) {
                                EventHandler eh = nonApplicationEvents [errorEvent] as EventHandler;
                                if (eh != null){
                                        try {
                                                eh (this, EventArgs.Empty);
                                        } catch (ThreadAbortException taex){
                                                context.ClearError ();
                                                if (FlagEnd.Value == taex.ExceptionState)
                                                        // This happens on Redirect() or End()
                                                        Thread.ResetAbort ();
                                                else
                                                        // This happens on Thread.Abort()
                                                        context.AddError (taex);
                                        } catch (Exception ee){
                                                context.AddError (ee);
                                        }
                                }
                        }
                        stop_processing = true;
#if NET_2_0
                        // we want to remove configuration from the cache in case of 
                        // invalid resource not exists to prevent DOS attack.
                        HttpException httpEx = e as HttpException;
                        if (httpEx != null && httpEx.GetHttpCode () == 404) {
                                removeConfigurationFromCache = true;
                        }
#endif
                }
                
                //
                // Ticks the clock: next step on the pipeline.
                //
                internal void Tick ()
                {
                        try {
#if TARGET_J2EE
                                if (context.Error is UnifyRequestException) {
                                        Exception ex = context.Error.InnerException;
                                        context.ClearError ();
                                        vmw.common.TypeUtils.Throw (ex);
                                }
                                try {
#endif          
                                if (pipeline.MoveNext ()){
                                        if ((bool)pipeline.Current)
                                                PipelineDone ();
                                }
#if TARGET_J2EE
                                }
                                catch (Exception ex) {
                                        if (ex is ThreadAbortException && 
                                                ((ThreadAbortException) ex).ExceptionState == FlagEnd.Value)
                                                throw;
                                        if (context.WorkerRequest is IHttpUnifyWorkerRequest) {
                                                context.ClearError ();
                                                context.AddError (new UnifyRequestException (ex));
                                                return;
                                        }
                                        else
                                                throw;
                                }
#endif
                        } catch (ThreadAbortException taex) {
                                object obj = taex.ExceptionState;
                                Thread.ResetAbort ();
                                stop_processing = true;
                                if (obj is StepTimeout)
                                        ProcessError (new HttpException ("The request timed out."));
                                else {
                                        context.ClearError ();
                                        if (FlagEnd.Value != obj)
                                                context.AddError (taex);
                                }

                                PipelineDone ();
                        } catch (Exception e) {
                                stop_processing = true;
                                ProcessError (e);
                                PipelineDone ();
                        }
                }

                void Resume ()
                {
                        if (in_begin)
                                must_yield = false;
                        else
                                Tick ();
                }
                
                //
                // Invoked when our async callback called from RunHooks completes,
                // we restart the pipeline here.
                //
                void async_callback_completed_cb (IAsyncResult ar)
                {
                        if (current_ai.end != null){
                                try {
                                        current_ai.end (ar);
                                } catch (Exception e) {
                                        ProcessError (e);
                                }
                        }

                        Resume ();
                }

                void async_handler_complete_cb (IAsyncResult ar)
                {
                        IHttpAsyncHandler async_handler = ar != null ? ar.AsyncState as IHttpAsyncHandler : null;

                        try {
                                if (async_handler != null)
                                        async_handler.EndProcessRequest (ar);
                        } catch (Exception e){
                                ProcessError (e);
                        }
                        
                        Resume ();
                }
                
                //
                // This enumerator yields whether processing must be stopped:
                //    true:  processing of the pipeline must be stopped
                //    false: processing of the pipeline must not be stopped
                //
                IEnumerable RunHooks (Delegate list)
                {
                        Delegate [] delegates = list.GetInvocationList ();

                        foreach (EventHandler d in delegates){
                                if (d.Target != null && (d.Target is AsyncInvoker)){
                                        current_ai = (AsyncInvoker) d.Target;

                                        try {
                                                must_yield = true;
                                                in_begin = true;
                                                context.BeginTimeoutPossible ();
                                                current_ai.begin (this, EventArgs.Empty, async_callback_completed_cb, current_ai.data);
                                        } finally {
                                                in_begin = false;
                                                context.EndTimeoutPossible ();
                                        }

                                        //
                                        // If things are still moving forward, yield this
                                        // thread now
                                        //
                                        if (must_yield)
                                                yield return stop_processing;
                                        else if (stop_processing)
                                                yield return true;
                                } else {
                                        try {
                                                context.BeginTimeoutPossible ();
                                                d (this, EventArgs.Empty);
                                        } finally {
                                                context.EndTimeoutPossible ();
                                        }
                                        if (stop_processing)
                                                yield return true;
                                }
                        }
                }

                static void FinalErrorWrite (HttpResponse response, string error)
                {
                        try {
                                response.Write (error);
                                response.Flush (true);
                        } catch {
                                response.Close ();
                        }
                }

                void OutputPage ()
                {
                        if (context.Error == null){
                                try {
                                        context.Response.Flush (true);
                                } catch (Exception e){
                                        context.AddError (e);
                                }
                        }

                        Exception error = context.Error;
                        if (error != null){
                                HttpResponse response = context.Response;

                                if (!response.HeadersSent){
                                        response.ClearHeaders ();
                                        response.ClearContent ();

                                        if (error is HttpException){
                                                response.StatusCode = ((HttpException)error).GetHttpCode ();
                                        } else {
                                                error = new HttpException ("", error);
                                                response.StatusCode = 500;
                                        }
                                        HttpException httpEx = (HttpException) error;
                                        if (!RedirectCustomError (ref httpEx))
                                                FinalErrorWrite (response, httpEx.GetHtmlErrorMessage ());
                                        else
                                                response.Flush (true);
                                } else {
                                        if (!(error is HttpException))
                                                error = new HttpException ("", error);
                                        FinalErrorWrite (response, ((HttpException) error).GetHtmlErrorMessage ());
                                }
                        }
                        
                }
                
                //
                // Invoked at the end of the pipeline execution
                //
                void PipelineDone ()
                {
                        try {
                                EventHandler handler = Events [EndRequestEvent] as EventHandler;
                                if (handler != null)
                                        handler (this, EventArgs.Empty);
                        } catch (Exception e){
                                ProcessError (e);
                        }

                        try {
                                OutputPage ();
                        } catch (ThreadAbortException taex) {
                                ProcessError (taex);
                                Thread.ResetAbort ();
                        } catch (Exception e) {
                                Console.WriteLine ("Internal error: OutputPage threw an exception " + e);
                        } finally {
                                context.WorkerRequest.EndOfRequest();
                                if (factory != null && context.Handler != null){
                                        factory.ReleaseHandler (context.Handler);
                                        context.Handler = null;
                                        factory = null;
                                }
#if NET_2_0
                                context.PopHandler ();
#endif
                                // context = null; -> moved to PostDone
                                pipeline = null;
                                current_ai = null;
                        }
                        PostDone ();

                        if (begin_iar != null)
                                begin_iar.Complete ();
                        else
                                done.Set ();

                        requests_total_counter.Increment ();
                }

                class Tim {
                        string name;
                        DateTime start;

                        public Tim () {
                        }

                        public Tim (string name) {
                                this.name = name;
                        }

                        public string Name {
                                get { return name; }
                                set { name = value; }
                        }

                        public void Start () {
                                start = DateTime.UtcNow;
                        }

                        public void Stop () {
                                Console.WriteLine ("{0}: {1}ms", name, (DateTime.UtcNow - start).TotalMilliseconds);
                        }
                }

                Tim tim;
                [Conditional ("PIPELINE_TIMER")]
                void StartTimer (string name)
                {
                        if (tim == null)
                                tim = new Tim ();
                        tim.Name = name;
                        tim.Start ();
                }

                [Conditional ("PIPELINE_TIMER")]
                void StopTimer ()
                {
                        tim.Stop ();
                }

                //
                // Events fired as described in `Http Runtime Support, HttpModules,
                // Handling Public Events'
                //
                IEnumerator Pipeline ()
                {
                        Delegate eventHandler;
                        if (stop_processing)
                                yield return true;

#if NET_2_0
                        context.MapRequestHandlerDone = false;
#endif
                        StartTimer ("BeginRequest");
                        eventHandler = Events [BeginRequestEvent];
                        if (eventHandler != null) {
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        }
                        StopTimer ();
                        
                        StartTimer ("AuthenticateRequest");
                        eventHandler = Events [AuthenticateRequestEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();

                        StartTimer ("DefaultAuthentication");
                        if (DefaultAuthentication != null)
                                foreach (bool stop in RunHooks (DefaultAuthentication))
                                        yield return stop;
                        StopTimer ();

#if NET_2_0
                        StartTimer ("PostAuthenticateRequest");
                        eventHandler = Events [PostAuthenticateRequestEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();
#endif
                        StartTimer ("AuthorizeRequest");
                        eventHandler = Events [AuthorizeRequestEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();
#if NET_2_0
                        StartTimer ("PostAuthorizeRequest");
                        eventHandler = Events [PostAuthorizeRequestEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();
#endif

                        StartTimer ("ResolveRequestCache");
                        eventHandler = Events [ResolveRequestCacheEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();

#if NET_2_0
                        StartTimer ("PostResolveRequestCache");
                        eventHandler = Events [PostResolveRequestCacheEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();

                        StartTimer ("MapRequestHandler");
                        // As per http://msdn2.microsoft.com/en-us/library/bb470252(VS.90).aspx
                        eventHandler = Events [MapRequestHandlerEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();
                        context.MapRequestHandlerDone = true;
#endif
                        
                        StartTimer ("GetHandler");
                        // Obtain the handler for the request.
                        IHttpHandler handler = null;
                        try {
                                handler = GetHandler (context, context.Request.CurrentExecutionFilePath);
                                context.Handler = handler;
#if NET_2_0
                                context.PushHandler (handler);
#endif
                        } catch (FileNotFoundException fnf){
#if TARGET_JVM
                                Console.WriteLine ("$$$$$$$$$$:Sys.Web Pipeline");
                                Console.WriteLine (fnf.ToString ());
#endif
                                if (context.Request.IsLocal)
                                        ProcessError (new HttpException (404, String.Format ("File not found {0}", fnf.FileName), fnf, context.Request.FilePath));
                                else
                                        ProcessError (new HttpException (404, "File not found: " + Path.GetFileName (fnf.FileName), context.Request.FilePath));
                        } catch (DirectoryNotFoundException dnf){
                                if (!context.Request.IsLocal)
                                        dnf = null; // Do not "leak" real path information
                                ProcessError (new HttpException (404, "Directory not found", dnf));
                        } catch (Exception e) {
                                ProcessError (e);
                        }

                        StopTimer ();
                        if (stop_processing)
                                yield return true;

#if NET_2_0
                        StartTimer ("PostMapRequestHandler");
                        eventHandler = Events [PostMapRequestHandlerEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();
#endif

                        StartTimer ("AcquireRequestState");
                        eventHandler = Events [AcquireRequestStateEvent];
                        if (eventHandler != null){
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        }
                        StopTimer ();
                        
#if NET_2_0
                        StartTimer ("PostAcquireRequestState");
                        eventHandler = Events [PostAcquireRequestStateEvent];
                        if (eventHandler != null){
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        }
                        StopTimer ();
#endif
                        
                        //
                        // From this point on, we need to ensure that we call
                        // ReleaseRequestState, so the code below jumps to
                        // `release:' to guarantee it rather than yielding.
                        //
                        StartTimer ("PreRequestHandlerExecute");
                        eventHandler = Events [PreRequestHandlerExecuteEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        if (stop)
                                                goto release;
                        StopTimer ();
                        
                                
#if TARGET_J2EE
                processHandler:
                        bool doProcessHandler = false;
#endif
                        
#if NET_2_0
                        IHttpHandler ctxHandler = context.Handler;
                        if (ctxHandler != null && handler != ctxHandler) {
                                context.PopHandler ();
                                handler = ctxHandler;
                                context.PushHandler (handler);
                        }
#endif

                        StartTimer ("ProcessRequest");
                        try {
                                context.BeginTimeoutPossible ();
                                if (handler != null){
                                        IHttpAsyncHandler async_handler = handler as IHttpAsyncHandler;
                                        
                                        if (async_handler != null){
                                                must_yield = true;
                                                in_begin = true;
                                                async_handler.BeginProcessRequest (context, async_handler_complete_cb, handler);
                                        } else {
                                                must_yield = false;
                                                handler.ProcessRequest (context);
#if TARGET_J2EE
                                                IHttpExtendedHandler extHandler=handler as IHttpExtendedHandler;
                                                doProcessHandler = extHandler != null && !extHandler.IsCompleted;
#endif
                                        }
                                }
                                if (context.Error != null)
                                        throw new TargetInvocationException(context.Error);
                        } finally {
                                in_begin = false;
                                context.EndTimeoutPossible ();
                        }
                        StopTimer ();
#if TARGET_J2EE
                        if (doProcessHandler) {
                                yield return false;
                                goto processHandler;
                        }
#endif
                        if (must_yield)
                                yield return stop_processing;
                        else if (stop_processing)
                                goto release;
                        
                        // These are executed after the application has returned
                        
                        StartTimer ("PostRequestHandlerExecute");
                        eventHandler = Events [PostRequestHandlerExecuteEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        if (stop)
                                                goto release;
                        StopTimer ();
                        
                release:
                        StartTimer ("ReleaseRequestState");
                        eventHandler = Events [ReleaseRequestStateEvent];
                        if (eventHandler != null){
#pragma warning disable 219
                                foreach (bool stop in RunHooks (eventHandler)) {
                                        //
                                        // Ignore the stop signal while release the state
                                        //
                                        
                                }
#pragma warning restore 219
                        }
                        StopTimer ();
                        
                        if (stop_processing)
                                yield return true;

#if NET_2_0
                        StartTimer ("PostReleaseRequestState");
                        eventHandler = Events [PostReleaseRequestStateEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();
#endif

                        StartTimer ("Filter");
                        if (context.Error == null)
                                context.Response.DoFilter (true);
                        StopTimer ();

                        StartTimer ("UpdateRequestCache");
                        eventHandler = Events [UpdateRequestCacheEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();

#if NET_2_0
                        StartTimer ("PostUpdateRequestCache");
                        eventHandler = Events [PostUpdateRequestCacheEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();

                        StartTimer ("LogRequest");
                        eventHandler = Events [LogRequestEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();

                        StartTimer ("PostLogRequest");
                        eventHandler = Events [PostLogRequestEvent];
                        if (eventHandler != null)
                                foreach (bool stop in RunHooks (eventHandler))
                                        yield return stop;
                        StopTimer ();
#endif
                        StartTimer ("PipelineDone");
                        PipelineDone ();
                        StopTimer ();
                }


                internal CultureInfo GetThreadCulture (HttpRequest request, CultureInfo culture, bool isAuto)
                {
#if NET_2_0
                        if (!isAuto)
                                return culture;
                        CultureInfo ret = null;
                        string[] languages = request.UserLanguages;
                        try {
                                if (languages != null && languages.Length > 0)
                                        ret = CultureInfo.CreateSpecificCulture (languages[0]);
                        } catch {
                        }
                        
                        if (ret == null)
                                ret = culture;
                        
                        return ret;
#else
                        return culture;
#endif
                }


                void PreStart ()
                {
#if NET_2_0
                        GlobalizationSection cfg;
                        cfg = (GlobalizationSection) WebConfigurationManager.GetSection ("system.web/globalization");
                        app_culture = cfg.GetCulture ();
                        autoCulture = cfg.IsAutoCulture;
                        appui_culture = cfg.GetUICulture ();
                        autoUICulture = cfg.IsAutoUICulture;
#else
                        GlobalizationConfiguration cfg;
                        cfg = GlobalizationConfiguration.GetInstance (null);
                        if (cfg != null) {
                                app_culture = cfg.Culture;
                                autoCulture = false; // to hush the warning
                                appui_culture = cfg.UICulture;
                                autoUICulture = false; // to hush the warning
                        }
#endif

#if !TARGET_J2EE
                        context.StartTimeoutTimer ();
#endif
                        Thread th = Thread.CurrentThread;
                        if (app_culture != null) {
                                prev_app_culture = th.CurrentCulture;
                                CultureInfo new_app_culture = GetThreadCulture (Request, app_culture, autoCulture);
                                if (!new_app_culture.Equals (CultureInfo.InvariantCulture))
                                        th.CurrentCulture = new_app_culture;
                        }

                        if (appui_culture != null) {
                                prev_appui_culture = th.CurrentUICulture;
                                CultureInfo new_app_culture = GetThreadCulture (Request, appui_culture, autoUICulture);
                                if (!new_app_culture.Equals (CultureInfo.InvariantCulture))
                                        th.CurrentUICulture = new_app_culture;
                        }

#if !TARGET_JVM
                        prev_user = Thread.CurrentPrincipal;
#endif
                }

                void PostDone ()
                {
#if NET_2_0
                        if (removeConfigurationFromCache) {
                                WebConfigurationManager.RemoveConfigurationFromCache (context);
                                removeConfigurationFromCache = false;
                        }
#endif
                        Thread th = Thread.CurrentThread;
#if !TARGET_JVM
                        if (Thread.CurrentPrincipal != prev_user)
                                Thread.CurrentPrincipal = prev_user;
#endif
                        if (prev_appui_culture != null && prev_appui_culture != th.CurrentUICulture)
                                th.CurrentUICulture = prev_appui_culture;
                        if (prev_app_culture != null && prev_app_culture != th.CurrentCulture)
                                th.CurrentCulture = prev_app_culture;

#if !TARGET_J2EE
                        if (context == null)
                                context = HttpContext.Current;
                        context.StopTimeoutTimer ();
#endif
                        context.Request.ReleaseResources ();
                        context.Response.ReleaseResources ();
                        context = null;
                        session = null;
                        HttpContext.Current = null;
                }

                void Start (object x)
                {
                        CultureInfo[] cultures = x as CultureInfo[];
                        if (cultures != null && cultures.Length == 2) {
                                Thread ct = Thread.CurrentThread;
                                ct.CurrentCulture = cultures [0];
                                ct.CurrentUICulture = cultures [1];
                        }
                        
                        try {
                                InitOnce (true);
                        } catch (Exception e) {
#if NET_2_0
                                initialization_exception = e;
#endif
                                FinalErrorWrite (context.Response, new HttpException ("", e).GetHtmlErrorMessage ());
                                PipelineDone ();
                                return;
                        }

                        HttpContext.Current = Context;
                        PreStart ();
                        pipeline = Pipeline ();
                        Tick ();
                }

                const string HANDLER_CACHE = "@@HttpHandlerCache@@";

                internal static Hashtable GetHandlerCache ()
                {
                        Cache cache = HttpRuntime.InternalCache;
                        Hashtable ret = cache [HANDLER_CACHE] as Hashtable;

                        if (ret == null) {
                                ret = new Hashtable ();
                                cache.Insert (HANDLER_CACHE, ret);
                        }

                        return ret;
                }
                
                internal static void ClearHandlerCache ()
                {
                        Hashtable cache = GetHandlerCache ();
                        cache.Clear ();
                }
                
                object LocateHandler (HttpRequest req, string verb, string url)
                {
                        Hashtable cache = GetHandlerCache ();
                        string id = String.Concat (verb, url);
                        object ret = cache [id];

                        if (ret != null)
                                return ret;

                        bool allowCache;
#if NET_2_0
                        HttpHandlersSection httpHandlersSection = WebConfigurationManager.GetSection ("system.web/httpHandlers", req.Path, req.Context) as HttpHandlersSection;
                        ret = httpHandlersSection.LocateHandler (verb, url, out allowCache);
#else
                        HandlerFactoryConfiguration factory_config = (HandlerFactoryConfiguration) HttpContext.GetAppConfig ("system.web/httpHandlers");
                        ret = factory_config.LocateHandler (verb, url, out allowCache);
#endif

                        IHttpHandler handler = ret as IHttpHandler;
                        if (allowCache && handler != null && handler.IsReusable)
                                cache [id] = ret;
                        
                        return ret;
                }

                internal IHttpHandler GetHandler (HttpContext context, string url)
                {
                        return GetHandler (context, url, false);
                }
                
                // Used by HttpServerUtility.Execute
                internal IHttpHandler GetHandler (HttpContext context, string url, bool ignoreContextHandler)
                {
                        if (!ignoreContextHandler && context.Handler != null)
                                return context.Handler;
                        
                        HttpRequest request = context.Request;
                        string verb = request.RequestType;
                        
                        IHttpHandler handler = null;
                        object o = LocateHandler (request, verb, url);
                        
                        factory = o as IHttpHandlerFactory;
                        if (factory == null) {
                                handler = (IHttpHandler) o;
                        } else {
                                handler = factory.GetHandler (context, verb, url, request.MapPath (url));
                        }

                        return handler;
                }
                
                void IHttpHandler.ProcessRequest (HttpContext context)
                {
                        begin_iar = null;
                        this.context = context;
                        done.Reset ();

                        Start (null);
                        done.WaitOne ();
                }

                //
                // This is used by FireOnAppStart, when we init the application
                // as the context is required to be set at that point (the user
                // might call methods that require it on that hook).
                //
                internal void SetContext (HttpContext context)
                {
                        this.context = context;
                }

                internal void SetSession (HttpSessionState session)
                {
                        this.session = session;
                }

                IAsyncResult IHttpAsyncHandler.BeginProcessRequest (HttpContext context, AsyncCallback cb, object extraData)
                {
                        this.context = context;
                        done.Reset ();
                        
                        begin_iar = new AsyncRequestState (done, cb, extraData);

                        CultureInfo[] cultures = new CultureInfo [2];
                        cultures [0] = Thread.CurrentThread.CurrentCulture;
                        cultures [1] = Thread.CurrentThread.CurrentUICulture;
                        
#if TARGET_JVM
                        if (true)
#else
                        if (Thread.CurrentThread.IsThreadPoolThread)
#endif
                                Start (null);
                        else
                                ThreadPool.QueueUserWorkItem (new WaitCallback (Start), cultures);
                        
                        return begin_iar;
                }

                void IHttpAsyncHandler.EndProcessRequest (IAsyncResult result)
                {
#if TARGET_J2EE
                        if (result == null)
                                result = begin_iar;
#endif
                        if (!result.IsCompleted)
                                result.AsyncWaitHandle.WaitOne ();
                        begin_iar = null;
                }

                public virtual void Init ()
                {
                }

                bool IHttpHandler.IsReusable {
                        get {
                                return true;
                        }
                }
                
#region internals
                internal void ClearError ()
                {
                        context.ClearError ();
                }

                bool RedirectErrorPage (string error_page)
                {
                        if (context.Request.QueryString ["aspxerrorpath"] != null)
                                return false;

                        Response.Redirect (error_page + "?aspxerrorpath=" + Request.Path, false);
                        return true;
                }
                                                        
                bool RedirectCustomError (ref HttpException httpEx)
                {
                        try {
                        if (!context.IsCustomErrorEnabledUnsafe)
                                return false;
                        
#if NET_2_0
                        CustomErrorsSection config = (CustomErrorsSection)WebConfigurationManager.GetSection ("system.web/customErrors");
#else
                        CustomErrorsConfig config = null;
                        try {
                                config = (CustomErrorsConfig) context.GetConfig ("system.web/customErrors");
                        } catch { }
#endif
                        
                        if (config == null) {
                                if (context.ErrorPage != null)
                                        return RedirectErrorPage (context.ErrorPage);
                                
                                return false;
                        }
                        
#if NET_2_0
                        CustomError err = config.Errors [context.Response.StatusCode.ToString()];
                        string redirect = err == null ? null : err.Redirect;
#else
                        string redirect =  config [context.Response.StatusCode];
#endif
                        if (redirect == null) {
                                redirect = context.ErrorPage;
                                if (redirect == null)
                                        redirect = config.DefaultRedirect;
                        }
                        
                        if (redirect == null)
                                return false;
                        
                        return RedirectErrorPage (redirect);
                        }
                        catch (Exception ex) {
                                httpEx = new HttpException (500, "", ex);
                                return false;
                        }
                }
#endregion              
                internal static string BinDirectory
                {
                        get {
                                if (binDirectory == null) {
                                        AppDomainSetup setup = AppDomain.CurrentDomain.SetupInformation;
                                        string baseDir = setup.ApplicationBase;
                                        string bindir;
                                        
                                        foreach (string dir in BinDirs) {
                                                bindir = Path.Combine (baseDir, dir);
                                                if (!Directory.Exists (bindir))
                                                        continue;
                                                binDirectory = bindir;
                                                break;
                                        }
                                }

                                return binDirectory;
                        }
                }

                internal static string[] BinDirectoryAssemblies
                {
                        get {
                                ArrayList binDlls = null;
                                string[] dlls;
                                
                                string bindir = BinDirectory;
                                if (bindir != null) {
                                        binDlls = new ArrayList ();
                                        dlls = Directory.GetFiles (bindir, "*.dll");
                                        binDlls.AddRange (dlls);
                                }

                                if (binDlls == null)
                                        return new string[] {};
                                
                                return (string[]) binDlls.ToArray (typeof (string));
                        }
                }
                                        
                internal static Type LoadType (string typeName)
                {
                        return LoadType (typeName, false);
                }
                
                internal static Type LoadType (string typeName, bool throwOnMissing)
                {
                        Type type = Type.GetType (typeName);
                        if (type != null)
                                return type;

#if !TARGET_JVM
                        Assembly [] assemblies = AppDomain.CurrentDomain.GetAssemblies ();
                        foreach (Assembly ass in assemblies) {
                                type = ass.GetType (typeName, false);
                                if (type != null)
                                        return type;
                        }

#if NET_2_0
                        IList tla = System.Web.Compilation.BuildManager.TopLevelAssemblies;
                        if (tla != null && tla.Count > 0) {
                                foreach (Assembly asm in tla) {
                                        if (asm == null)
                                                continue;
                                        type = asm.GetType (typeName, false);
                                        if (type != null)
                                                return type;
                                }
                        }
#endif

                        Exception loadException = null;
                        try {
                                type = null;
                                type = LoadTypeFromBin (typeName);
                        } catch (Exception ex) {
                                loadException = ex;
                        }
                        
                        if (type != null)
                                return type;
#endif
                        if (throwOnMissing)
                                throw new TypeLoadException (String.Format ("Type '{0}' cannot be found", typeName), loadException);
                        
                        return null;
                }

                internal static Type LoadTypeFromBin (string typeName)
                {
                        Type type = null;
                        
                        foreach (string s in BinDirectoryAssemblies) {
                                Assembly binA = null;
                                
                                try {
                                        binA = Assembly.LoadFrom (s);
                                } catch (FileLoadException) {
                                        // ignore
                                        continue;
                                } catch (BadImageFormatException) {
                                        // ignore
                                        continue;
                                }
                                
                                type = binA.GetType (typeName, false);
                                if (type == null)
                                        continue;
                                
                                return type;
                        }

                        return null;
                }
        }

        //
        // Based on Fritz' Onion's AsyncRequestState class for asynchronous IHttpAsyncHandlers
        // 
        class AsyncRequestState : IAsyncResult {
                AsyncCallback cb;
                object cb_data;
                bool completed;
                ManualResetEvent complete_event = null;
                
                internal AsyncRequestState (ManualResetEvent complete_event, AsyncCallback cb, object cb_data)
                {
                        this.cb = cb;
                        this.cb_data = cb_data;
                        this.complete_event = complete_event;
                }

                internal void Complete ()
                {
                        completed = true;
                        try {
                                //
                                // TODO: if this throws an error, we have no way of reporting it
                                // Not really too bad, since the only failure might be
                                // `HttpRuntime.request_processed'.   
                                //
                                if (cb != null)
                                        cb (this);
                        } catch {
                        }
                        
                        complete_event.Set ();
                }

                public object AsyncState {
                        get {
                                return cb_data;
                        }
                }

                public bool CompletedSynchronously {
                        get {
                                return false;
                        }
                }

                public bool IsCompleted {
                        get {
                                return completed;
                        }
                }

                public WaitHandle AsyncWaitHandle {
                        get {
                                return complete_event;
                        }
                }
        }

#region Helper classes
        
        //
        // A wrapper to keep track of begin/end pairs
        //
        class AsyncInvoker {
                public BeginEventHandler begin;
                public EndEventHandler end;
                public object data;
                
                public AsyncInvoker (BeginEventHandler bh, EndEventHandler eh, object d)
                {
                        begin = bh;
                        end = eh;
                        data = d;
                }

                public AsyncInvoker (BeginEventHandler bh, EndEventHandler eh)
                {
                        begin = bh;
                        end = eh;
                }
                
                public void Invoke (object sender, EventArgs e)
                {
                        throw new Exception ("This is just a dummy");
                }
        }
#endregion
}