HostingEnvironment.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / xsp / System / Web / Hosting / HostingEnvironment.cs / 1305376 / HostingEnvironment.cs

                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.Hosting { 
    using Microsoft.Win32; 
    using System;
    using System.Runtime.Caching; 
    using System.Configuration;
    using System.Collections;
    using System.Diagnostics.CodeAnalysis;
    using System.Globalization; 
    using System.Runtime.InteropServices;
    using System.Runtime.Remoting; 
    using System.Runtime.Remoting.Messaging; 
    using System.Text;
    using System.Threading; 
    using System.IO;
    using System.Web;
    using System.Web.Caching;
    using System.Web.Compilation; 
    using System.Web.Configuration;
    using System.Web.Util; 
    using System.Security; 
    using System.Security.Principal;
    using System.Security.Permissions; 
    using System.Web.Management;
    using System.Security.Policy;

    [Flags] 
    internal enum HostingEnvironmentFlags {
        Default = 0, 
        HideFromAppManager = 1, 
        ThrowHostingInitErrors = 2,
        DontCallAppInitialize = 4, 
        ClientBuildManager = 8,
        SupportsMultiTargeting = 16,
    }
 
    [Serializable]
    internal class HostingEnvironmentParameters { 
        private HostingEnvironmentFlags _hostingFlags; 
        private ClientBuildManagerParameter _clientBuildManagerParameter;
        private string _precompTargetPhysicalDir; 

        public HostingEnvironmentFlags HostingFlags {
            get { return _hostingFlags; }
            set { _hostingFlags = value; } 
        }
 
        // Directory where the precompiled site is placed 
        public string PrecompilationTargetPhysicalDirectory {
            get { return _precompTargetPhysicalDir; } 
            set {
                _precompTargetPhysicalDir = FileUtil.FixUpPhysicalDirectory(value);
            }
        } 

        // Determines the behavior of the precompilation 
        public ClientBuildManagerParameter ClientBuildManagerParameter { 
            get { return _clientBuildManagerParameter; }
            set { _clientBuildManagerParameter = value; } 
        }
    }

    public sealed class HostingEnvironment : MarshalByRefObject { 

        private static HostingEnvironment _theHostingEnvironment; 
        private EventHandler _onAppDomainUnload; 
        private ApplicationManager _appManager;
        private HostingEnvironmentParameters _hostingParameters; 
        private IApplicationHost _appHost;
        private bool _externalAppHost;
        private IConfigMapPath _configMapPath;
        private IConfigMapPath2 _configMapPath2; 
        private IntPtr _configToken;
 
        private IdentitySection _appIdentity; 
        private IntPtr _appIdentityToken;
        private bool _appIdentityTokenSet; 

        private String _appId;
        private VirtualPath _appVirtualPath;
        private String _appPhysicalPath; 
        private String _siteName;
        private String _siteID; 
        private String _appConfigPath; 

        private bool   _isBusy; 
        private int    _busyCount;

        private bool _removedFromAppManager;
        private bool _appDomainShutdownStarted; 
        private bool _shutdownInitiated;
        private bool _shutdownInProgress; 
        private String _shutDownStack; 

        private int _inTrimCache; 
        private ObjectCacheHost _objectCacheHost;

        // table of well know objects keyed by type
        private Hashtable _wellKnownObjects = new Hashtable(); 

        // list of registered IRegisteredObject instances 
        private Hashtable _registeredObjects = new Hashtable(); 

        // callback to make InitiateShutdown non-blocking 
        private WaitCallback _initiateShutdownWorkItemCallback;

        // inside app domain idle shutdown logic
        private IdleTimeoutMonitor _idleTimeoutMonitor; 

        private static IProcessHostSupportFunctions _functions; 
        private static bool _hasBeenRemovedFromAppManangerTable; 

        public override Object InitializeLifetimeService() { 
            return null; // never expire lease
        }

        ///  
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
        public HostingEnvironment() { 
            if (_theHostingEnvironment != null) 
                throw new InvalidOperationException(SR.GetString(SR.Only_1_HostEnv));
 
            // remember singleton HostingEnvironment in a static
            _theHostingEnvironment = this;

            // start watching for app domain unloading 
            _onAppDomainUnload = new EventHandler(OnAppDomainUnload);
            Thread.GetDomain().DomainUnload += _onAppDomainUnload; 
        } 

        internal long TrimCache(int percent) { 
            if (Interlocked.Exchange(ref _inTrimCache, 1) != 0)
                return 0;
            try {
                long trimmedOrExpired = 0; 
                // do nothing if we're shutting down
                if (!_shutdownInitiated) { 
                    trimmedOrExpired = HttpRuntime.CacheInternal.TrimCache(percent); 
                    if (_objectCacheHost != null && !_shutdownInitiated) {
                        trimmedOrExpired += _objectCacheHost.TrimCache(percent); 
                    }
                }
                return trimmedOrExpired;
            } 
            finally {
                Interlocked.Exchange(ref _inTrimCache, 0); 
            } 
        }
 
        private void OnAppDomainUnload(Object unusedObject, EventArgs unusedEventArgs) {
            Debug.Trace("PipelineRuntime", "HE.OnAppDomainUnload");

            Thread.GetDomain().DomainUnload -= _onAppDomainUnload; 

            // check for unexpected shutdown 
            if (!_removedFromAppManager) { 
                RemoveThisAppDomainFromAppManagerTableOnce();
            } 

            HttpRuntime.RecoverFromUnexceptedAppDomainUnload();

            // call Stop on all registered objects with immediate = true 
            StopRegisteredObjects(true);
 
            // notify app manager 
            if (_appManager != null) {
                // disconnect the real app host and substitute it with a bogus one 
                // to avoid exceptions later when app host is called (it normally wouldn't)
                IApplicationHost originalAppHost = null;

                if (_externalAppHost) { 
                    originalAppHost = _appHost;
                    _appHost = new SimpleApplicationHost(_appVirtualPath, _appPhysicalPath); 
                    _externalAppHost = false; 
                }
 
                _appManager.HostingEnvironmentShutdownComplete(_appId, originalAppHost);
            }

            // free the config access token 
            if (_configToken != IntPtr.Zero) {
                UnsafeNativeMethods.CloseHandle(_configToken); 
                _configToken = IntPtr.Zero; 
            }
        } 

        //
        // Initialization
        // 

        // called from app manager right after app domain (and hosting env) is created 
        internal void Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel) { 
            Initialize(appManager, appHost, configMapPathFactory, hostingParameters, policyLevel, null);
        } 

        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
        internal void Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory,
            HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, 
            Exception appDomainCreationException) {
 
            _hostingParameters = hostingParameters; 

            HostingEnvironmentFlags hostingFlags = HostingEnvironmentFlags.Default; 
            if (_hostingParameters != null)
                hostingFlags = _hostingParameters.HostingFlags;

            // Keep track of the app manager, unless HideFromAppManager flag was passed 
            if ((hostingFlags & HostingEnvironmentFlags.HideFromAppManager) == 0)
                _appManager = appManager; 
 
            if ((hostingFlags & HostingEnvironmentFlags.ClientBuildManager) != 0) {
                BuildManagerHost.InClientBuildManager = true; 
            }

            if ((hostingFlags & HostingEnvironmentFlags.SupportsMultiTargeting) != 0) {
                BuildManagerHost.SupportsMultiTargeting = true; 
            }
 
            // 
            // init config system using private config if applicable
            // 
            if (appHost is ISAPIApplicationHost && !ServerConfig.UseMetabase) {
                string rootWebConfigPath = ((ISAPIApplicationHost)appHost).ResolveRootWebConfigPath();
                if (!String.IsNullOrEmpty(rootWebConfigPath)) {
                    Debug.Assert(File.Exists(rootWebConfigPath), "File.Exists(rootWebConfigPath)"); 
                    HttpConfigurationSystem.RootWebConfigurationFilePath = rootWebConfigPath;
                } 
 
                // we need to explicit create a COM proxy in this app domain
                // so we don't go back to the default domain or have lifetime issues 
                // remember support functions
                IProcessHostSupportFunctions proxyFunctions = ((ISAPIApplicationHost)appHost).SupportFunctions;
                if (null != proxyFunctions) {
                    _functions = Misc.CreateLocalSupportFunctions(proxyFunctions); 
                }
            } 
 
            _appId = HttpRuntime.AppDomainAppIdInternal;
            _appVirtualPath = HttpRuntime.AppDomainAppVirtualPathObject; 
            _appPhysicalPath = HttpRuntime.AppDomainAppPathInternal;
            _appHost = appHost;

            _configMapPath = configMapPathFactory.Create(_appVirtualPath.VirtualPathString, _appPhysicalPath); 
            HttpConfigurationSystem.EnsureInit(_configMapPath, true, false);
 
            // attempt to cache and use IConfigMapPath2 provider 
            // which supports VirtualPath's to save on conversions
            _configMapPath2 = _configMapPath as IConfigMapPath2; 


            _initiateShutdownWorkItemCallback = new WaitCallback(this.InitiateShutdownWorkItemCallback);
 
            // notify app manager
            if (_appManager != null) { 
                _appManager.HostingEnvironmentActivated(CacheMemorySizePressure.EffectiveProcessMemoryLimit); 
            }
 
            // make sure there is always app host
            if (_appHost == null) {
                _appHost = new SimpleApplicationHost(_appVirtualPath, _appPhysicalPath);
            } 
            else {
                _externalAppHost = true; 
            } 

            // remember the token to access config 
            _configToken = _appHost.GetConfigToken();

            // Start with a MapPath based virtual path provider
            _mapPathBasedVirtualPathProvider = new MapPathBasedVirtualPathProvider(); 
            _virtualPathProvider = _mapPathBasedVirtualPathProvider;
 
            // initiaze HTTP-independent features 
            HttpRuntime.InitializeHostingFeatures(hostingFlags, policyLevel, appDomainCreationException);
 
            // VSWhidbey 393259. Do not monitor idle timeout for CBM since Venus
            // will always restart a new appdomain if old one is shutdown.
            if (!BuildManagerHost.InClientBuildManager) {
                // start monitoring for idle inside app domain 
                StartMonitoringForIdleTimeout();
            } 
 
            // notify app manager if the app domain limit is violated
            EnforceAppDomainLimit(); 

            // get application identity (for explicit impersonation mode)
            GetApplicationIdentity();
 
            // call AppInitialize, unless the flag says not to do it (e.g. CBM scenario).
            // Also, don't call it if HostingInit failed (VSWhidbey 210495) 
            if(!HttpRuntime.HostingInitFailed) { 
                try {
                    BuildManager.CallPreStartInitMethods(); 
                    if ((hostingFlags & HostingEnvironmentFlags.DontCallAppInitialize) == 0) {
                        BuildManager.CallAppInitializeMethod();
                    }
                } 
                catch (Exception e) {
                    // could throw compilation errors in 'code' - report them with first http request 
                    HttpRuntime.InitializationException = e; 

                    if ((hostingFlags & HostingEnvironmentFlags.ThrowHostingInitErrors) != 0) { 
                        throw;
                    }
                }
            } 
        }
 
        private void InitializeObjectCacheHostPrivate() { 
            // set ObjectCacheHost if the Host is not already set
            if (ObjectCache.Host == null) { 
                ObjectCacheHost objectCacheHost = new ObjectCacheHost();
                ObjectCache.Host = objectCacheHost;
                _objectCacheHost = objectCacheHost;
            } 
        }
 
        internal static void InitializeObjectCacheHost() { 
            if (_theHostingEnvironment != null) {
                _theHostingEnvironment.InitializeObjectCacheHostPrivate(); 
            }
        }

        private void StartMonitoringForIdleTimeout() { 
            HostingEnvironmentSection hostEnvConfig = RuntimeConfig.GetAppLKGConfig().HostingEnvironment;
 
            TimeSpan idleTimeout = (hostEnvConfig != null) ? hostEnvConfig.IdleTimeout : HostingEnvironmentSection.DefaultIdleTimeout; 

            // always create IdleTimeoutMonitor (even if config value is TimeSpan.MaxValue (infinite) 
            // IdleTimeoutMonitor is also needed to keep the last event for app domain set trimming
            // and the timer is used to trim the application instances
            _idleTimeoutMonitor = new IdleTimeoutMonitor(idleTimeout);
        } 

        // enforce app domain limit 
        private void EnforceAppDomainLimit() { 
            if (_appManager == null)  /// detached app domain
                return; 

            int limit = 0;

            try { 
                ProcessModelSection pmConfig = RuntimeConfig.GetMachineConfig().ProcessModel;
                limit = pmConfig.MaxAppDomains; 
            } 
            catch {
            } 

            if (limit > 0 && _appManager.AppDomainsCount >= limit) {
                // current app domain doesn't count yet (not in the table)
                // that's why '>=' above 
                _appManager.ReduceAppDomainsCount(limit);
            } 
        } 

        private void GetApplicationIdentity() { 
            // if the explicit impersonation is set, use it instead of UNC identity
            try {
                IdentitySection c = RuntimeConfig.GetAppConfig().Identity;
                if (c.Impersonate && c.ImpersonateToken != IntPtr.Zero) { 
                    _appIdentity = c;
                    _appIdentityToken = c.ImpersonateToken; 
                } 
                else {
                    _appIdentityToken = _configToken; 
                }
                _appIdentityTokenSet = true;
            }
            catch { 
            }
        } 
 

        // If an exception was thrown during initialization, return it. 
        public static Exception InitializationException {
            get {
                return HttpRuntime.InitializationException;
            } 
        }
 
        // called from app manager (from management APIs) 
        internal ApplicationInfo GetApplicationInfo() {
            return new ApplicationInfo(_appId, _appVirtualPath, _appPhysicalPath); 
        }

        //
        // Shutdown logic 
        //
        [PermissionSet(SecurityAction.Assert, Unrestricted = true)] 
        private void StopRegisteredObjects(bool immediate) { 
            if (_registeredObjects.Count > 0) {
                ArrayList list = new ArrayList(); 

                lock (this) {
                    foreach (DictionaryEntry e in _registeredObjects) {
                        Object x = e.Key; 

                        // well-known objects first 
                        if (IsWellKnownObject(x)) { 
                            list.Insert(0, x);
                        } 
                        else {
                            list.Add(x);
                        }
                    } 
                }
 
                foreach (IRegisteredObject obj in list) { 
                    try {
                        obj.Stop(immediate); 
                    }
                    catch {
                    }
                } 
            }
        } 
 
        private void InitiateShutdownWorkItemCallback(Object state /*not used*/) {
            Debug.Trace("HostingEnvironmentShutdown", "Shutting down: appId=" + _appId); 

            // no registered objects -- shutdown
            if (_registeredObjects.Count == 0) {
                Debug.Trace("HostingEnvironmentShutdown", "No registered objects"); 
                ShutdownThisAppDomainOnce();
                return; 
            } 

            // call Stop on all registered objects with immediate = false 
            StopRegisteredObjects(false);

            // no registered objects -- shutdown now
            if (_registeredObjects.Count == 0) { 
                Debug.Trace("HostingEnvironmentShutdown", "All registered objects gone after Stop(false)");
                ShutdownThisAppDomainOnce(); 
                return; 
            }
 
            // if not everything shutdown synchronously give it some time.
            int shutdownTimeoutSeconds = HostingEnvironmentSection.DefaultShutdownTimeout;
            HostingEnvironmentSection hostEnvConfig = RuntimeConfig.GetAppLKGConfig().HostingEnvironment;
            if (hostEnvConfig != null) { 
                shutdownTimeoutSeconds = (int) hostEnvConfig.ShutdownTimeout.TotalSeconds;
            } 
            Debug.Trace("HostingEnvironmentShutdown", "Waiting for " + shutdownTimeoutSeconds + " sec..."); 

            DateTime waitUntil = DateTime.UtcNow.AddSeconds(shutdownTimeoutSeconds); 
            while (_registeredObjects.Count > 0 && DateTime.UtcNow < waitUntil) {
                Thread.Sleep(100);
            }
 
            Debug.Trace("HostingEnvironmentShutdown", "Shutdown timeout (" + shutdownTimeoutSeconds + " sec) expired");
 
            // call Stop on all registered objects with immediate = true 
            StopRegisteredObjects(true);
 
            // no registered objects -- shutdown now
            if (_registeredObjects.Count == 0) {
                Debug.Trace("HostingEnvironmentShutdown", "All registered objects gone after Stop(true)");
                ShutdownThisAppDomainOnce(); 
                return;
            } 
 
            // shutdown regardless
            Debug.Trace("HostingEnvironmentShutdown", "Forced shutdown: " + _registeredObjects.Count + " registered objects left"); 
            _registeredObjects = new Hashtable();
            ShutdownThisAppDomainOnce();
        }
 
        // app domain shutdown logic
        internal void InitiateShutdownInternal() { 
            Debug.Trace("AppManager", "HostingEnvironment.InitiateShutdownInternal appId=" + _appId); 

            bool proceed = false; 

            if (!_shutdownInitiated) {
                lock (this) {
                    if (!_shutdownInitiated) { 
                        _shutdownInProgress = true;
                        proceed = true; 
                        _shutdownInitiated = true; 
                    }
                } 
            }

            if (!proceed) {
                return; 
            }
 
            HttpRuntime.SetShutdownReason(ApplicationShutdownReason.HostingEnvironment, "HostingEnvironment initiated shutdown"); 

            new EnvironmentPermission(PermissionState.Unrestricted).Assert(); 
            try {
                _shutDownStack = Environment.StackTrace;
            }
            finally { 
                CodeAccessPermission.RevertAssert();
            } 
 
            // this should only be called once, before the cache is disposed, and
            // the config records are released. 
            HttpRuntime.CoalesceNotifications();

            RemoveThisAppDomainFromAppManagerTableOnce();
 
            // stop all registered objects without blocking
            ThreadPool.QueueUserWorkItem(this._initiateShutdownWorkItemCallback); 
        } 

        internal bool HasBeenRemovedFromAppManagerTable { 
            get {
                return _hasBeenRemovedFromAppManangerTable;
            }
            set { 
                _hasBeenRemovedFromAppManangerTable = value;
            } 
        } 

        private void RemoveThisAppDomainFromAppManagerTableOnce() { 
            bool proceed = false;
            if (!_removedFromAppManager) {
                lock (this) {
                    if (!_removedFromAppManager) { 
                        proceed = true;
                        _removedFromAppManager = true; 
                    } 
                }
            } 

            if (!proceed)
                return;
 
            if (_appManager != null) {
                Debug.Trace("AppManager", "Removing HostingEnvironment from AppManager table, appId=" + _appId); 
                _appManager.HostingEnvironmentShutdownInitiated(_appId, this); 
            }
#if DBG 
            Debug.Trace("FileChangesMonitorIgnoreSubdirChange",
                        "*** REMOVE APPMANAGER TABLE" + DateTime.Now.ToString("hh:mm:ss.fff", CultureInfo.InvariantCulture)
                        + ": _appId=" + _appId);
#endif 
        }
 
        private void ShutdownThisAppDomainOnce() { 
            bool proceed = false;
 
            if (!_appDomainShutdownStarted) {
                lock (this) {
                    if (!_appDomainShutdownStarted) {
                        proceed = true; 
                        _appDomainShutdownStarted = true;
                    } 
                } 
            }
 
            if (!proceed)
                return;

            Debug.Trace("AppManager", "HostingEnvironment - shutting down AppDomain, appId=" + _appId); 

            // stop the timer used for idle timeout 
            if (_idleTimeoutMonitor != null) { 
                _idleTimeoutMonitor.Stop();
                _idleTimeoutMonitor = null; 
            }

            while (_inTrimCache == 1) {
                Thread.Sleep(100); 
            }
 
            // 
            HttpRuntime.SetUserForcedShutdown();
 
            //WOS 1400290: CantUnloadAppDomainException in ISAPI mode, wait until HostingEnvironment.ShutdownThisAppDomainOnce completes
            _shutdownInProgress = false;

            HttpRuntime.ShutdownAppDomainWithStackTrace(ApplicationShutdownReason.HostingEnvironment, 
                                                        SR.GetString(SR.Hosting_Env_Restart),
                                                        _shutDownStack); 
        } 

        // 
        // internal methods called by app manager
        //

        // helper for app manager to implement AppHost.CreateAppHost 
        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
        internal ObjectHandle CreateInstance(String assemblyQualifiedName) { 
            Type type = Type.GetType(assemblyQualifiedName, true); 
            return new ObjectHandle(Activator.CreateInstance(type));
        } 

        // start well known object
        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
        internal ObjectHandle CreateWellKnownObjectInstance(String assemblyQualifiedName, bool failIfExists) { 
            Type type = Type.GetType(assemblyQualifiedName, true);
            IRegisteredObject obj = null; 
            String key = type.FullName; 
            bool exists = false;
 
            lock (this) {
                obj = _wellKnownObjects[key] as IRegisteredObject;

                if (obj == null) { 
                    obj = (IRegisteredObject)Activator.CreateInstance(type);
                    _wellKnownObjects[key] = obj; 
                } 
                else {
                    exists = true; 
                }
            }

            if (exists && failIfExists) { 
                throw new InvalidOperationException(SR.GetString(SR.Wellknown_object_already_exists, key));
            } 
 
            return new ObjectHandle(obj);
        } 

        // check if well known object
        private bool IsWellKnownObject(Object obj) {
            bool found = false; 
            String key = obj.GetType().FullName;
 
            lock (this) { 
                if (_wellKnownObjects[key] == obj) {
                    found = true; 
                }
            }

            return found; 
        }
 
        // find well known object by type 
        internal ObjectHandle FindWellKnownObject(String assemblyQualifiedName) {
            Type type = Type.GetType(assemblyQualifiedName, true); 
            IRegisteredObject obj = null;
            String key = type.FullName;

            lock (this) { 
                obj = _wellKnownObjects[key] as IRegisteredObject;
            } 
 
            return (obj != null) ? new ObjectHandle(obj) : null;
        } 

        // stop well known object by type
        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
        internal void StopWellKnownObject(String assemblyQualifiedName) { 
            Type type = Type.GetType(assemblyQualifiedName, true);
            IRegisteredObject obj = null; 
            String key = type.FullName; 

            lock (this) { 
                obj = _wellKnownObjects[key] as IRegisteredObject;
                if (obj != null) {
                    _wellKnownObjects.Remove(key);
                    obj.Stop(false); 
                }
            } 
        } 

        internal bool IsIdle() { 
            bool isBusy = _isBusy;
            _isBusy = false;
            return (!isBusy && _busyCount == 0);
        } 

        internal bool GetIdleValue() { 
            return (!_isBusy && _busyCount == 0); 
        }
 
        internal void IncrementBusyCountInternal() {
            _isBusy = true;
            Interlocked.Increment(ref _busyCount);
        } 

        internal void DecrementBusyCountInternal() { 
            _isBusy = true; 
            Interlocked.Decrement(ref _busyCount);
 
            // Notify idle timeout monitor
            IdleTimeoutMonitor itm = _idleTimeoutMonitor;
            if (itm != null) {
                itm.LastEvent = DateTime.UtcNow; 
            }
        } 
        internal void IsUnloaded() 
        {
            return; 
        }

        private void MessageReceivedInternal() {
            _isBusy = true; 

            IdleTimeoutMonitor itm = _idleTimeoutMonitor; 
            if (itm != null) { 
                itm.LastEvent = DateTime.UtcNow;
            } 
        }

        // the busier the app domain the higher the score
        internal int LruScore { 
            get {
                if (_busyCount > 0) 
                    return _busyCount; 

                IdleTimeoutMonitor itm = _idleTimeoutMonitor; 

                if (itm == null)
                    return 0;
 
                // return negative number of seconds since last activity
                return -(int)(DateTime.UtcNow - itm.LastEvent).TotalSeconds; 
            } 
        }
 
        internal static ApplicationManager GetApplicationManager() {
            if (_theHostingEnvironment == null)
                return null;
 
            return _theHostingEnvironment._appManager;
        } 
 
        //
        // private helpers 
        //

        // register protocol handler with hosting environment
        private void RegisterRunningObjectInternal(IRegisteredObject obj) { 
            lock (this) {
                _registeredObjects[obj] = obj; 
            } 
        }
 
        // unregister protocol handler from hosting environment
        private void UnregisterRunningObjectInternal(IRegisteredObject obj) {
            bool lastOne = false;
 
            lock (this) {
                // if it is a well known object, remove it from that table as well 
                String key = obj.GetType().FullName; 
                if (_wellKnownObjects[key] == obj) {
                    _wellKnownObjects.Remove(key); 
                }

                // remove from running objects list
                _registeredObjects.Remove(obj); 

                if (_registeredObjects.Count == 0) 
                    lastOne = true; 
            }
 
            if (!lastOne)
                return;

            // shutdown app domain after last protocol handler is gone 

            InitiateShutdownInternal(); 
        } 

        // site name 
        private String GetSiteName() {
            if (_siteName == null) {
                lock (this) {
                    if (_siteName == null) { 
                        String s = null;
 
                        if (_appHost != null) { 
                            //
                            InternalSecurityPermissions.Unrestricted.Assert(); 
                            try {
                                s = _appHost.GetSiteName();
                            }
                            finally { 
                                CodeAccessPermission.RevertAssert();
                            } 
                        } 

                        if (s == null) 
                            s = WebConfigurationHost.DefaultSiteName;

                        _siteName = s;
                    } 
                }
            } 
 
            return _siteName;
        } 

        // site ID
        private String GetSiteID() {
            if (_siteID == null) { 
                lock (this) {
                    if (_siteID == null) { 
                        String s = null; 

                        if (_appHost != null) { 
                            //
                            InternalSecurityPermissions.Unrestricted.Assert();
                            try {
                                s = _appHost.GetSiteID(); 
                            }
                            finally { 
                                CodeAccessPermission.RevertAssert(); 
                            }
                        } 

                        if (s == null)
                            s = WebConfigurationHost.DefaultSiteID;
 
                        _siteID = s.ToLower(CultureInfo.InvariantCulture);
                    } 
                } 
            }
 
            return _siteID;
        }

        // Return the configPath for the app, e.g. "machine/webroot/1/myapp" 
        private String GetAppConfigPath() {
            if (_appConfigPath == null) { 
                _appConfigPath = WebConfigurationHost.GetConfigPathFromSiteIDAndVPath(SiteID, ApplicationVirtualPathObject); 
            }
 
            return _appConfigPath;
        }

        // Return the call context slot name to use for a virtual path 
        private static string GetFixedMappingSlotName(VirtualPath virtualPath) {
            return "MapPath_" + virtualPath.VirtualPathString.ToLowerInvariant().GetHashCode().ToString(CultureInfo.InvariantCulture); 
        } 

        /* 
         * Map a virtual path to a physical path.  i.e. the physicalPath will be returned
         * when MapPath is called on the virtual path, bypassing the IApplicationHost
         */
        private static string GetVirtualPathToFileMapping(VirtualPath virtualPath) { 
            return CallContext.GetData(GetFixedMappingSlotName(virtualPath)) as string;
        } 
 
        /*
         * Map a virtual path to a physical path.  i.e. the physicalPath will be returned 
         * when MapPath is called on the virtual path, bypassing the IApplicationHost
         */
        internal static object AddVirtualPathToFileMapping(
            VirtualPath virtualPath, string physicalPath) { 

            // Save the mapping in the call context, using a key derived from the 
            // virtual path.  The mapping is only valid for the duration of the request. 
            CallContext.SetData(GetFixedMappingSlotName(virtualPath), physicalPath);
 
            // Return a mapping object to keep track of the virtual path, and of the current
            // virtualPathProvider.
            VirtualPathToFileMappingState state = new VirtualPathToFileMappingState();
            state.VirtualPath = virtualPath; 
            state.VirtualPathProvider = _theHostingEnvironment._virtualPathProvider;
 
            // Always use the MapPathBasedVirtualPathProvider, otherwise the mapping mechanism 
            // doesn't work (VSWhidbey 420702)
            _theHostingEnvironment._virtualPathProvider = _theHostingEnvironment._mapPathBasedVirtualPathProvider; 

            return state;
        }
 
        internal static void ClearVirtualPathToFileMapping(object state) {
 
            VirtualPathToFileMappingState mapping = (VirtualPathToFileMappingState)state; 

            // Clear the mapping from the call context 
            CallContext.SetData(GetFixedMappingSlotName(mapping.VirtualPath), null);

            // Restore the previous VirtualPathProvider
            _theHostingEnvironment._virtualPathProvider = mapping.VirtualPathProvider; 
        }
 
        private string MapPathActual(VirtualPath virtualPath, bool permitNull) 
        {
            string result = null; 

            Debug.Assert(virtualPath != null);

            virtualPath.FailIfRelativePath(); 

            VirtualPath reqpath = virtualPath; 
 
            if (String.CompareOrdinal(reqpath.VirtualPathString, _appVirtualPath.VirtualPathString) == 0) {
                // for application path don't need to call app host 
                Debug.Trace("MapPath", reqpath  +" is the app path");
                result = _appPhysicalPath;
            }
            else { 
                using (new ProcessImpersonationContext()) {
                    // If there is a mapping for this virtual path in the call context, use it 
                    result = GetVirtualPathToFileMapping(reqpath); 

                    if (result == null) { 
                        // call host's mappath
                        if (_configMapPath == null) {
                            Debug.Trace("MapPath", "Missing _configMapPath");
                            throw new InvalidOperationException(SR.GetString(SR.Cannot_map_path, reqpath)); 
                        }
                        Debug.Trace("MapPath", "call ConfigMapPath (" + reqpath + ")"); 
 
                        // see if the IConfigMapPath provider implements the interface
                        // with VirtualPath 
                        try {
                            if (null != _configMapPath2) {
                                result = _configMapPath2.MapPath(GetSiteID(), reqpath);
                            } 
                            else {
                                result = _configMapPath.MapPath(GetSiteID(), reqpath.VirtualPathString); 
                            } 
                            if (HttpRuntime.IsMapPathRelaxed)
                                result = HttpRuntime.GetRelaxedMapPathResult(result); 
                        } catch {
                            if (HttpRuntime.IsMapPathRelaxed)
                                result = HttpRuntime.GetRelaxedMapPathResult(null);
                            else 
                                throw;
                        } 
                    } 
                }
            } 

            if (String.IsNullOrEmpty(result)) {
                Debug.Trace("MapPath", "null Result");
                if (!permitNull) { 
                    if (HttpRuntime.IsMapPathRelaxed)
                        result = HttpRuntime.GetRelaxedMapPathResult(null); 
                    else 
                        throw new InvalidOperationException(SR.GetString(SR.Cannot_map_path, reqpath));
                } 
            }
            else {
                // ensure extra '\\' in the physical path if the virtual path had extra '/'
                // and the other way -- no extra '\\' in physical if virtual didn't have it. 
                if (virtualPath.HasTrailingSlash) {
                    if (!UrlPath.PathEndsWithExtraSlash(result) && !UrlPath.PathIsDriveRoot(result)) 
                        result = result + "\\"; 
                }
                else { 
                    if (UrlPath.PathEndsWithExtraSlash(result) && !UrlPath.PathIsDriveRoot(result))
                        result = result.Substring(0, result.Length - 1);
                }
 
                Debug.Trace("MapPath", "    result=" + result);
            } 
 
            return result;
        } 

        //
        // public static methods
        // 

 
        // register protocol handler with hosting environment 
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
        public static void RegisterObject(IRegisteredObject obj) { 
            if (_theHostingEnvironment != null)
                _theHostingEnvironment.RegisterRunningObjectInternal(obj);
        }
 

        // unregister protocol handler from hosting environment 
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)] 
        public static void UnregisterObject(IRegisteredObject obj) {
            if (_theHostingEnvironment != null) 
                _theHostingEnvironment.UnregisterRunningObjectInternal(obj);
        }

        // 
        // public static methods for the user code to call
        // 
 

        public static void IncrementBusyCount() { 
            if (_theHostingEnvironment != null)
                _theHostingEnvironment.IncrementBusyCountInternal();
        }
 

        public static void DecrementBusyCount() { 
            if (_theHostingEnvironment != null) 
                _theHostingEnvironment.DecrementBusyCountInternal();
        } 


        public static void MessageReceived() {
            if (_theHostingEnvironment != null) 
                _theHostingEnvironment.MessageReceivedInternal();
        } 
 
        public static bool InClientBuildManager {
            get { 
                return BuildManagerHost.InClientBuildManager;
            }
        }
 
        public static bool IsHosted {
            get { 
                return (_theHostingEnvironment != null); 
            }
        } 

        internal static bool IsUnderIISProcess {
            get {
                String process = VersionInfo.ExeName; 

                return process == "aspnet_wp" || 
                       process == "w3wp" || 
                       process == "inetinfo";
            } 
        }

        internal static bool IsUnderIIS6Process {
            get { 
                return VersionInfo.ExeName == "w3wp";
            } 
        } 

        public static IApplicationHost ApplicationHost { 
            //DevDivBugs 109864: ASP.NET: path discovery issue - In low trust, it is possible to get the physical path of any virtual path on the machine
            [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
            get {
                if (_theHostingEnvironment == null) 
                    return null;
 
                return _theHostingEnvironment._appHost; 
            }
        } 

       internal static IApplicationHost ApplicationHostInternal {
            get {
                if (_theHostingEnvironment == null) 
                    return null;
 
                return _theHostingEnvironment._appHost; 
            }
        } 

        internal IApplicationHost InternalApplicationHost {
            get {
                return _appHost; 
            }
        } 
 
        internal static int BusyCount {
            get { 
                if (_theHostingEnvironment == null)
                    return 0;

                return _theHostingEnvironment._busyCount; 
            }
        } 
 
        internal static bool ShutdownInitiated {
            get { 
                if (_theHostingEnvironment == null)
                    return false;

                return _theHostingEnvironment._shutdownInitiated; 
            }
        } 
 

        internal static bool ShutdownInProgress { 
            get {
                if (_theHostingEnvironment == null)
                    return false;
 
                return _theHostingEnvironment._shutdownInProgress;
            } 
        } 

 
        /// 
        ///    The application ID (metabase path in IIS hosting).
        /// 
        public static String ApplicationID { 
            get {
                if (_theHostingEnvironment == null) 
                    return null; 

                InternalSecurityPermissions.AspNetHostingPermissionLevelHigh.Demand(); 
                return _theHostingEnvironment._appId;
            }
        }
 
        internal static String ApplicationIDNoDemand {
            get { 
                if (_theHostingEnvironment == null) { 
                    return null;
                } 

                return _theHostingEnvironment._appId;
            }
        } 

 
        ///  
        ///    Physical path to the application root.
        ///  
        public static String ApplicationPhysicalPath {
            get {
                if (_theHostingEnvironment == null)
                    return null; 

                InternalSecurityPermissions.AppPathDiscovery.Demand(); 
                return _theHostingEnvironment._appPhysicalPath; 
            }
        } 


        /// 
        ///    Virtual path to the application root. 
        /// 
        public static String ApplicationVirtualPath { 
            get { 
                return VirtualPath.GetVirtualPathStringNoTrailingSlash(ApplicationVirtualPathObject);
            } 
        }

        internal static VirtualPath ApplicationVirtualPathObject {
            get { 
                if (_theHostingEnvironment == null)
                    return null; 
 
                return _theHostingEnvironment._appVirtualPath;
            } 
        }


        ///  
        ///    Site name.
        ///  
        public static String SiteName { 
            get {
                if (_theHostingEnvironment == null) 
                    return null;

                InternalSecurityPermissions.AspNetHostingPermissionLevelMedium.Demand();
                return _theHostingEnvironment.GetSiteName(); 
            }
        } 
 
        internal static String SiteNameNoDemand {
            get { 
                if (_theHostingEnvironment == null)
                    return null;

                return _theHostingEnvironment.GetSiteName(); 
            }
        } 
 
        internal static String SiteID {
            get { 
                if (_theHostingEnvironment == null)
                    return null;

                return _theHostingEnvironment.GetSiteID(); 
            }
        } 
 
        internal static IConfigMapPath ConfigMapPath {
            get { 
                if (_theHostingEnvironment == null)
                    return null;

                return _theHostingEnvironment._configMapPath; 
            }
        } 
 
        internal static String AppConfigPath {
            get { 
                if (_theHostingEnvironment == null) {
                    return null;
                }
 
                return _theHostingEnvironment.GetAppConfigPath();
            } 
        } 

 
        /// 
        ///    
        ///       Gets a reference to the System.Web.Cache.Cache object for the current request.
        ///     
        /// 
        public static Cache Cache { 
            get { return HttpRuntime.Cache; } 
        }
 
        // count of all app domain from app manager
        internal static int AppDomainsCount {
            get {
                ApplicationManager appManager = GetApplicationManager(); 
                return (appManager != null) ? appManager.AppDomainsCount : 0;
            } 
        } 

        internal static HostingEnvironmentParameters HostingParameters { 
            get {
                if (_theHostingEnvironment == null)
                    return null;
 
                return _theHostingEnvironment._hostingParameters;
            } 
        } 

        // Return an integer that is unique for each appdomain.  This can be used 
        // to create things like once-per-appdomain temp files without having different
        // processes/appdomains step on each other
        private static int s_appDomainUniqueInteger;
        internal static int AppDomainUniqueInteger { 
            get {
                if (s_appDomainUniqueInteger == 0) { 
                    s_appDomainUniqueInteger = Guid.NewGuid().GetHashCode(); 
                }
 
                return s_appDomainUniqueInteger;
            }
        }
 
        public static ApplicationShutdownReason ShutdownReason {
            get { return HttpRuntime.ShutdownReason; } 
        } 

        ///  
        ///    Initiate app domain unloading for the current app.
        /// 
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
        public static void InitiateShutdown() { 
            if (_theHostingEnvironment != null)
                _theHostingEnvironment.InitiateShutdownInternal(); 
        } 

        internal static void InitiateShutdownWithoutDemand() { 
            if (_theHostingEnvironment != null)
                _theHostingEnvironment.InitiateShutdownInternal();
        }
 
        /// 
        ///    Maps a virtual path to a physical path. 
        ///  
        public static string MapPath(string virtualPath) {
            return MapPath(VirtualPath.Create(virtualPath)); 
        }

        internal static string MapPath(VirtualPath virtualPath) {
            if (_theHostingEnvironment == null) 
                return null;
 
            String path = MapPathInternal(virtualPath); 

            if (path != null) 
                InternalSecurityPermissions.PathDiscovery(path).Demand();

            return path;
        } 

        internal static String MapPathInternal(string virtualPath) { 
            return MapPathInternal(VirtualPath.Create(virtualPath)); 
        }
 
        internal static String MapPathInternal(VirtualPath virtualPath) {
            if (_theHostingEnvironment == null) {
                return null;
            } 

            return _theHostingEnvironment.MapPathActual(virtualPath, false); 
        } 

        internal static String MapPathInternal(string virtualPath, bool permitNull) { 
            return MapPathInternal(VirtualPath.Create(virtualPath), permitNull);
        }

        internal static String MapPathInternal(VirtualPath virtualPath, bool permitNull) { 
            if (_theHostingEnvironment == null) {
                return null; 
            } 

            return _theHostingEnvironment.MapPathActual(virtualPath, permitNull); 
        }

        internal static string MapPathInternal(string virtualPath, string baseVirtualDir, bool allowCrossAppMapping) {
            return MapPathInternal(VirtualPath.Create(virtualPath), 
                VirtualPath.CreateNonRelative(baseVirtualDir), allowCrossAppMapping);
        } 
 
        internal static string MapPathInternal(VirtualPath virtualPath, VirtualPath baseVirtualDir, bool allowCrossAppMapping) {
            Debug.Assert(baseVirtualDir != null, "baseVirtualDir != null"); 

            // Combine it with the base and reduce
            virtualPath = baseVirtualDir.Combine(virtualPath);
 
            if (!allowCrossAppMapping && !virtualPath.IsWithinAppRoot)
                throw new ArgumentException(SR.GetString(SR.Cross_app_not_allowed, virtualPath)); 
 
            return MapPathInternal(virtualPath);
        } 

        internal static WebApplicationLevel GetPathLevel(String path) {
            WebApplicationLevel pathLevel = WebApplicationLevel.AboveApplication;
 
            if (_theHostingEnvironment != null && !String.IsNullOrEmpty(path)) {
                String appPath = ApplicationVirtualPath; 
 
                if (appPath == "/") {
                    if (path == "/") { 
                        pathLevel = WebApplicationLevel.AtApplication;
                    }
                    else if (path[0] == '/') {
                        pathLevel = WebApplicationLevel.BelowApplication; 
                    }
                } 
                else { 
                    if (StringUtil.EqualsIgnoreCase(appPath, path)) {
                        pathLevel = WebApplicationLevel.AtApplication; 
                    }
                    else if (path.Length > appPath.Length && path[appPath.Length] == '/' &&
                        StringUtil.StringStartsWithIgnoreCase(path, appPath)) {
 
                        pathLevel = WebApplicationLevel.BelowApplication;
                    } 
                } 
            }
 
            return pathLevel;
        }

 
        //
        // Impersonation helpers 
        // 
        // user token for the app (hosting / unc)
        internal static IntPtr ApplicationIdentityToken { 
            get {
                if (_theHostingEnvironment == null) {
                    return IntPtr.Zero;
                } 
                else {
                    if (_theHostingEnvironment._appIdentityTokenSet) 
                        return _theHostingEnvironment._appIdentityToken; 
                    else
                        return _theHostingEnvironment._configToken; 
                }
            }
        }
 

        // check if application impersonation != process impersonation 
        internal static bool HasHostingIdentity { 
            get {
                return (ApplicationIdentityToken != IntPtr.Zero); 
            }
        }

        // impersonate application identity 
        [SecurityPermission(SecurityAction.Demand, ControlPrincipal = true)]
        public static IDisposable Impersonate() { 
            return new ApplicationImpersonationContext(); 
        }
 
        // impersonate the given user identity
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
        public static IDisposable Impersonate(IntPtr token) {
            if (token == IntPtr.Zero) { 
                return new ProcessImpersonationContext();
            } 
            else { 
                return new ImpersonationContext(token);
            } 
        }

        // impersonate as configured for a given path
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)] 
        public static IDisposable Impersonate(IntPtr userToken, String virtualPath) {
            virtualPath = UrlPath.MakeVirtualPathAppAbsoluteReduceAndCheck(virtualPath); 
 
            if (_theHostingEnvironment == null) {
                return Impersonate(userToken); 
            }

            IdentitySection c = RuntimeConfig.GetConfig(virtualPath).Identity;
            if (c.Impersonate) { 
                if (c.ImpersonateToken != IntPtr.Zero) {
                    return new ImpersonationContext(c.ImpersonateToken); 
                } 
                else {
                    return new ImpersonationContext(userToken); 
                }
            }
            else {
                return new ApplicationImpersonationContext(); 
            }
        } 
 
        //
        //  Culture helpers 
        //

        public static IDisposable SetCultures() {
            return SetCultures(RuntimeConfig.GetAppLKGConfig().Globalization); 
        }
 
        public static IDisposable SetCultures(string virtualPath) { 
            virtualPath = UrlPath.MakeVirtualPathAppAbsoluteReduceAndCheck(virtualPath);
            return SetCultures(RuntimeConfig.GetConfig(virtualPath).Globalization); 
        }

        private static IDisposable SetCultures(GlobalizationSection gs) {
            CultureContext c = new CultureContext(); 

            if (gs != null) { 
                CultureInfo culture = null; 
                CultureInfo uiCulture = null;
 
                if (gs.Culture != null && gs.Culture.Length > 0) {
                    try {
                        culture = HttpServerUtility.CreateReadOnlyCultureInfo(gs.Culture);
                    } 
                    catch {
                    } 
                } 

                if (gs.UICulture != null && gs.UICulture.Length > 0) { 
                    try {
                        uiCulture = HttpServerUtility.CreateReadOnlyCultureInfo(gs.UICulture);
                    }
                    catch { 
                    }
                } 
 
                c.SetCultures(culture, uiCulture);
            } 

            return c;
        }
 

        class CultureContext : IDisposable { 
            CultureInfo _savedCulture; 
            CultureInfo _savedUICulture;
 
            internal CultureContext() {
            }

            void IDisposable.Dispose() { 
                RestoreCultures();
            } 
 
            internal void SetCultures(CultureInfo culture, CultureInfo uiCulture) {
                CultureInfo currentCulture = Thread.CurrentThread.CurrentCulture; 
                CultureInfo currentUICulture = Thread.CurrentThread.CurrentUICulture;

                if (culture != null && culture != currentCulture) {
                    Thread.CurrentThread.CurrentCulture = culture; 
                    _savedCulture = currentCulture;
                } 
 
                if (uiCulture != null && uiCulture != currentCulture) {
                    Thread.CurrentThread.CurrentUICulture = uiCulture; 
                    _savedUICulture = currentUICulture;
                }
            }
 
            internal void RestoreCultures() {
                if (_savedCulture != null && _savedCulture != Thread.CurrentThread.CurrentCulture) { 
                    Thread.CurrentThread.CurrentCulture = _savedCulture; 
                    _savedCulture = null;
                } 

                if (_savedUICulture != null && _savedUICulture != Thread.CurrentThread.CurrentUICulture) {
                    Thread.CurrentThread.CurrentUICulture = _savedUICulture;
                    _savedUICulture = null; 
                }
            } 
        } 

        // 
        // VirtualPathProvider related code
        //

        private VirtualPathProvider _virtualPathProvider; 
        private VirtualPathProvider _mapPathBasedVirtualPathProvider;
 
 
        public static VirtualPathProvider VirtualPathProvider {
            get { 
                if (_theHostingEnvironment == null)
                    return null;

                return _theHostingEnvironment._virtualPathProvider; 
            }
        } 
 
        internal static bool UsingMapPathBasedVirtualPathProvider {
            get { 
                if (_theHostingEnvironment == null)
                    return true;

                return (_theHostingEnvironment._virtualPathProvider == 
                    _theHostingEnvironment._mapPathBasedVirtualPathProvider);
            } 
        } 

        // [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.High)] 
        // Removed the above LinkDemand for AspNetHostingPermissionLevel.High. If we decide to add VPP
        // support for config in the future, we should have a separate API with a demand for registering
        // VPPs supporting configuration.
        public static void RegisterVirtualPathProvider(VirtualPathProvider virtualPathProvider) { 

            if (_theHostingEnvironment == null) 
                throw new InvalidOperationException(); 

            // Ignore the VirtualPathProvider on precompiled sites (VSWhidbey 368169,404844) 
            if (BuildManager.IsPrecompiledApp)
                return;

            RegisterVirtualPathProviderInternal(virtualPathProvider); 
        }
 
        internal static void RegisterVirtualPathProviderInternal(VirtualPathProvider virtualPathProvider) { 
            VirtualPathProvider previous = _theHostingEnvironment._virtualPathProvider;
            _theHostingEnvironment._virtualPathProvider = virtualPathProvider; 

            // Give it the previous provider so it can delegate if needed
            virtualPathProvider.Initialize(previous);
        } 

        // Helper class used to keep track of state when using 
        // AddVirtualPathToFileMapping & ClearVirtualPathToFileMapping 
        internal class VirtualPathToFileMappingState {
            internal VirtualPath VirtualPath; 
            internal VirtualPathProvider VirtualPathProvider;
        }

        internal static IProcessHostSupportFunctions SupportFunctions { 
            get {
                return _functions; 
            } 
            set {
                _functions = value; 
            }
        }

        [SuppressMessage("Microsoft.Naming", "CA1705:LongAcronymsShouldBePascalCased", 
                         Justification="matches casing of config attribute")]
        public static int MaxConcurrentRequestsPerCPU { 
            get { 
                if (!HttpRuntime.UseIntegratedPipeline) {
                    throw new PlatformNotSupportedException(SR.GetString(SR.Requires_Iis_Integrated_Mode)); 
                }
                return UnsafeIISMethods.MgdGetMaxConcurrentRequestsPerCPU();
            }
            [SecurityPermission(SecurityAction.Demand, Unrestricted = true)] 
            set {
                if (!HttpRuntime.UseIntegratedPipeline) { 
                    throw new PlatformNotSupportedException(SR.GetString(SR.Requires_Iis_Integrated_Mode)); 
                }
                int hr = UnsafeIISMethods.MgdSetMaxConcurrentRequestsPerCPU(value); 
                switch (hr) {
                    case HResults.S_FALSE:
                        // Because "maxConcurrentRequestsPerCPU" is currently zero, we cannot set the value, since that would
                        // enable the feature, which can only be done via configuration. 
                        throw new InvalidOperationException(SR.GetString(SR.Queue_limit_is_zero, "maxConcurrentRequestsPerCPU"));
                    case HResults.E_INVALIDARG: 
                        // The value must be greater than zero.  A value of zero would disable the feature, but this can only be done via configuration. 
                        throw new ArgumentException(SR.GetString(SR.Invalid_queue_limit));
                } 
            }
        }

        [SuppressMessage("Microsoft.Naming", "CA1705:LongAcronymsShouldBePascalCased", 
                         Justification="matches casing of config attribute")]
        public static int MaxConcurrentThreadsPerCPU { 
            get { 
                if (!HttpRuntime.UseIntegratedPipeline) {
                    throw new PlatformNotSupportedException(SR.GetString(SR.Requires_Iis_Integrated_Mode)); 
                }
                return UnsafeIISMethods.MgdGetMaxConcurrentThreadsPerCPU();
            }
            [SecurityPermission(SecurityAction.Demand, Unrestricted = true)] 
            set {
                if (!HttpRuntime.UseIntegratedPipeline) { 
                    throw new PlatformNotSupportedException(SR.GetString(SR.Requires_Iis_Integrated_Mode)); 
                }
                int hr = UnsafeIISMethods.MgdSetMaxConcurrentThreadsPerCPU(value); 
                switch (hr) {
                    case HResults.S_FALSE:
                        // Because "maxConcurrentThreadsPerCPU" is currently zero, we cannot set the value, since that would
                        // enable the feature, which can only be done via configuration. 
                        throw new InvalidOperationException(SR.GetString(SR.Queue_limit_is_zero, "maxConcurrentThreadsPerCPU"));
                    case HResults.E_INVALIDARG: 
                        // The value must be greater than zero.  A value of zero would disable the feature, but this can only be done via configuration. 
                        throw new ArgumentException(SR.GetString(SR.Invalid_queue_limit));
                } 
            }
        }

        ///  
        /// Returns the ASP.NET hosted domain.
        ///  
        internal AppDomain HostedAppDomain { 
            get {
                return AppDomain.CurrentDomain; 
            }
        }

    } 
}
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Web.Hosting { 
    using Microsoft.Win32; 
    using System;
    using System.Runtime.Caching; 
    using System.Configuration;
    using System.Collections;
    using System.Diagnostics.CodeAnalysis;
    using System.Globalization; 
    using System.Runtime.InteropServices;
    using System.Runtime.Remoting; 
    using System.Runtime.Remoting.Messaging; 
    using System.Text;
    using System.Threading; 
    using System.IO;
    using System.Web;
    using System.Web.Caching;
    using System.Web.Compilation; 
    using System.Web.Configuration;
    using System.Web.Util; 
    using System.Security; 
    using System.Security.Principal;
    using System.Security.Permissions; 
    using System.Web.Management;
    using System.Security.Policy;

    [Flags] 
    internal enum HostingEnvironmentFlags {
        Default = 0, 
        HideFromAppManager = 1, 
        ThrowHostingInitErrors = 2,
        DontCallAppInitialize = 4, 
        ClientBuildManager = 8,
        SupportsMultiTargeting = 16,
    }
 
    [Serializable]
    internal class HostingEnvironmentParameters { 
        private HostingEnvironmentFlags _hostingFlags; 
        private ClientBuildManagerParameter _clientBuildManagerParameter;
        private string _precompTargetPhysicalDir; 

        public HostingEnvironmentFlags HostingFlags {
            get { return _hostingFlags; }
            set { _hostingFlags = value; } 
        }
 
        // Directory where the precompiled site is placed 
        public string PrecompilationTargetPhysicalDirectory {
            get { return _precompTargetPhysicalDir; } 
            set {
                _precompTargetPhysicalDir = FileUtil.FixUpPhysicalDirectory(value);
            }
        } 

        // Determines the behavior of the precompilation 
        public ClientBuildManagerParameter ClientBuildManagerParameter { 
            get { return _clientBuildManagerParameter; }
            set { _clientBuildManagerParameter = value; } 
        }
    }

    public sealed class HostingEnvironment : MarshalByRefObject { 

        private static HostingEnvironment _theHostingEnvironment; 
        private EventHandler _onAppDomainUnload; 
        private ApplicationManager _appManager;
        private HostingEnvironmentParameters _hostingParameters; 
        private IApplicationHost _appHost;
        private bool _externalAppHost;
        private IConfigMapPath _configMapPath;
        private IConfigMapPath2 _configMapPath2; 
        private IntPtr _configToken;
 
        private IdentitySection _appIdentity; 
        private IntPtr _appIdentityToken;
        private bool _appIdentityTokenSet; 

        private String _appId;
        private VirtualPath _appVirtualPath;
        private String _appPhysicalPath; 
        private String _siteName;
        private String _siteID; 
        private String _appConfigPath; 

        private bool   _isBusy; 
        private int    _busyCount;

        private bool _removedFromAppManager;
        private bool _appDomainShutdownStarted; 
        private bool _shutdownInitiated;
        private bool _shutdownInProgress; 
        private String _shutDownStack; 

        private int _inTrimCache; 
        private ObjectCacheHost _objectCacheHost;

        // table of well know objects keyed by type
        private Hashtable _wellKnownObjects = new Hashtable(); 

        // list of registered IRegisteredObject instances 
        private Hashtable _registeredObjects = new Hashtable(); 

        // callback to make InitiateShutdown non-blocking 
        private WaitCallback _initiateShutdownWorkItemCallback;

        // inside app domain idle shutdown logic
        private IdleTimeoutMonitor _idleTimeoutMonitor; 

        private static IProcessHostSupportFunctions _functions; 
        private static bool _hasBeenRemovedFromAppManangerTable; 

        public override Object InitializeLifetimeService() { 
            return null; // never expire lease
        }

        ///  
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
        public HostingEnvironment() { 
            if (_theHostingEnvironment != null) 
                throw new InvalidOperationException(SR.GetString(SR.Only_1_HostEnv));
 
            // remember singleton HostingEnvironment in a static
            _theHostingEnvironment = this;

            // start watching for app domain unloading 
            _onAppDomainUnload = new EventHandler(OnAppDomainUnload);
            Thread.GetDomain().DomainUnload += _onAppDomainUnload; 
        } 

        internal long TrimCache(int percent) { 
            if (Interlocked.Exchange(ref _inTrimCache, 1) != 0)
                return 0;
            try {
                long trimmedOrExpired = 0; 
                // do nothing if we're shutting down
                if (!_shutdownInitiated) { 
                    trimmedOrExpired = HttpRuntime.CacheInternal.TrimCache(percent); 
                    if (_objectCacheHost != null && !_shutdownInitiated) {
                        trimmedOrExpired += _objectCacheHost.TrimCache(percent); 
                    }
                }
                return trimmedOrExpired;
            } 
            finally {
                Interlocked.Exchange(ref _inTrimCache, 0); 
            } 
        }
 
        private void OnAppDomainUnload(Object unusedObject, EventArgs unusedEventArgs) {
            Debug.Trace("PipelineRuntime", "HE.OnAppDomainUnload");

            Thread.GetDomain().DomainUnload -= _onAppDomainUnload; 

            // check for unexpected shutdown 
            if (!_removedFromAppManager) { 
                RemoveThisAppDomainFromAppManagerTableOnce();
            } 

            HttpRuntime.RecoverFromUnexceptedAppDomainUnload();

            // call Stop on all registered objects with immediate = true 
            StopRegisteredObjects(true);
 
            // notify app manager 
            if (_appManager != null) {
                // disconnect the real app host and substitute it with a bogus one 
                // to avoid exceptions later when app host is called (it normally wouldn't)
                IApplicationHost originalAppHost = null;

                if (_externalAppHost) { 
                    originalAppHost = _appHost;
                    _appHost = new SimpleApplicationHost(_appVirtualPath, _appPhysicalPath); 
                    _externalAppHost = false; 
                }
 
                _appManager.HostingEnvironmentShutdownComplete(_appId, originalAppHost);
            }

            // free the config access token 
            if (_configToken != IntPtr.Zero) {
                UnsafeNativeMethods.CloseHandle(_configToken); 
                _configToken = IntPtr.Zero; 
            }
        } 

        //
        // Initialization
        // 

        // called from app manager right after app domain (and hosting env) is created 
        internal void Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel) { 
            Initialize(appManager, appHost, configMapPathFactory, hostingParameters, policyLevel, null);
        } 

        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
        internal void Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory,
            HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, 
            Exception appDomainCreationException) {
 
            _hostingParameters = hostingParameters; 

            HostingEnvironmentFlags hostingFlags = HostingEnvironmentFlags.Default; 
            if (_hostingParameters != null)
                hostingFlags = _hostingParameters.HostingFlags;

            // Keep track of the app manager, unless HideFromAppManager flag was passed 
            if ((hostingFlags & HostingEnvironmentFlags.HideFromAppManager) == 0)
                _appManager = appManager; 
 
            if ((hostingFlags & HostingEnvironmentFlags.ClientBuildManager) != 0) {
                BuildManagerHost.InClientBuildManager = true; 
            }

            if ((hostingFlags & HostingEnvironmentFlags.SupportsMultiTargeting) != 0) {
                BuildManagerHost.SupportsMultiTargeting = true; 
            }
 
            // 
            // init config system using private config if applicable
            // 
            if (appHost is ISAPIApplicationHost && !ServerConfig.UseMetabase) {
                string rootWebConfigPath = ((ISAPIApplicationHost)appHost).ResolveRootWebConfigPath();
                if (!String.IsNullOrEmpty(rootWebConfigPath)) {
                    Debug.Assert(File.Exists(rootWebConfigPath), "File.Exists(rootWebConfigPath)"); 
                    HttpConfigurationSystem.RootWebConfigurationFilePath = rootWebConfigPath;
                } 
 
                // we need to explicit create a COM proxy in this app domain
                // so we don't go back to the default domain or have lifetime issues 
                // remember support functions
                IProcessHostSupportFunctions proxyFunctions = ((ISAPIApplicationHost)appHost).SupportFunctions;
                if (null != proxyFunctions) {
                    _functions = Misc.CreateLocalSupportFunctions(proxyFunctions); 
                }
            } 
 
            _appId = HttpRuntime.AppDomainAppIdInternal;
            _appVirtualPath = HttpRuntime.AppDomainAppVirtualPathObject; 
            _appPhysicalPath = HttpRuntime.AppDomainAppPathInternal;
            _appHost = appHost;

            _configMapPath = configMapPathFactory.Create(_appVirtualPath.VirtualPathString, _appPhysicalPath); 
            HttpConfigurationSystem.EnsureInit(_configMapPath, true, false);
 
            // attempt to cache and use IConfigMapPath2 provider 
            // which supports VirtualPath's to save on conversions
            _configMapPath2 = _configMapPath as IConfigMapPath2; 


            _initiateShutdownWorkItemCallback = new WaitCallback(this.InitiateShutdownWorkItemCallback);
 
            // notify app manager
            if (_appManager != null) { 
                _appManager.HostingEnvironmentActivated(CacheMemorySizePressure.EffectiveProcessMemoryLimit); 
            }
 
            // make sure there is always app host
            if (_appHost == null) {
                _appHost = new SimpleApplicationHost(_appVirtualPath, _appPhysicalPath);
            } 
            else {
                _externalAppHost = true; 
            } 

            // remember the token to access config 
            _configToken = _appHost.GetConfigToken();

            // Start with a MapPath based virtual path provider
            _mapPathBasedVirtualPathProvider = new MapPathBasedVirtualPathProvider(); 
            _virtualPathProvider = _mapPathBasedVirtualPathProvider;
 
            // initiaze HTTP-independent features 
            HttpRuntime.InitializeHostingFeatures(hostingFlags, policyLevel, appDomainCreationException);
 
            // VSWhidbey 393259. Do not monitor idle timeout for CBM since Venus
            // will always restart a new appdomain if old one is shutdown.
            if (!BuildManagerHost.InClientBuildManager) {
                // start monitoring for idle inside app domain 
                StartMonitoringForIdleTimeout();
            } 
 
            // notify app manager if the app domain limit is violated
            EnforceAppDomainLimit(); 

            // get application identity (for explicit impersonation mode)
            GetApplicationIdentity();
 
            // call AppInitialize, unless the flag says not to do it (e.g. CBM scenario).
            // Also, don't call it if HostingInit failed (VSWhidbey 210495) 
            if(!HttpRuntime.HostingInitFailed) { 
                try {
                    BuildManager.CallPreStartInitMethods(); 
                    if ((hostingFlags & HostingEnvironmentFlags.DontCallAppInitialize) == 0) {
                        BuildManager.CallAppInitializeMethod();
                    }
                } 
                catch (Exception e) {
                    // could throw compilation errors in 'code' - report them with first http request 
                    HttpRuntime.InitializationException = e; 

                    if ((hostingFlags & HostingEnvironmentFlags.ThrowHostingInitErrors) != 0) { 
                        throw;
                    }
                }
            } 
        }
 
        private void InitializeObjectCacheHostPrivate() { 
            // set ObjectCacheHost if the Host is not already set
            if (ObjectCache.Host == null) { 
                ObjectCacheHost objectCacheHost = new ObjectCacheHost();
                ObjectCache.Host = objectCacheHost;
                _objectCacheHost = objectCacheHost;
            } 
        }
 
        internal static void InitializeObjectCacheHost() { 
            if (_theHostingEnvironment != null) {
                _theHostingEnvironment.InitializeObjectCacheHostPrivate(); 
            }
        }

        private void StartMonitoringForIdleTimeout() { 
            HostingEnvironmentSection hostEnvConfig = RuntimeConfig.GetAppLKGConfig().HostingEnvironment;
 
            TimeSpan idleTimeout = (hostEnvConfig != null) ? hostEnvConfig.IdleTimeout : HostingEnvironmentSection.DefaultIdleTimeout; 

            // always create IdleTimeoutMonitor (even if config value is TimeSpan.MaxValue (infinite) 
            // IdleTimeoutMonitor is also needed to keep the last event for app domain set trimming
            // and the timer is used to trim the application instances
            _idleTimeoutMonitor = new IdleTimeoutMonitor(idleTimeout);
        } 

        // enforce app domain limit 
        private void EnforceAppDomainLimit() { 
            if (_appManager == null)  /// detached app domain
                return; 

            int limit = 0;

            try { 
                ProcessModelSection pmConfig = RuntimeConfig.GetMachineConfig().ProcessModel;
                limit = pmConfig.MaxAppDomains; 
            } 
            catch {
            } 

            if (limit > 0 && _appManager.AppDomainsCount >= limit) {
                // current app domain doesn't count yet (not in the table)
                // that's why '>=' above 
                _appManager.ReduceAppDomainsCount(limit);
            } 
        } 

        private void GetApplicationIdentity() { 
            // if the explicit impersonation is set, use it instead of UNC identity
            try {
                IdentitySection c = RuntimeConfig.GetAppConfig().Identity;
                if (c.Impersonate && c.ImpersonateToken != IntPtr.Zero) { 
                    _appIdentity = c;
                    _appIdentityToken = c.ImpersonateToken; 
                } 
                else {
                    _appIdentityToken = _configToken; 
                }
                _appIdentityTokenSet = true;
            }
            catch { 
            }
        } 
 

        // If an exception was thrown during initialization, return it. 
        public static Exception InitializationException {
            get {
                return HttpRuntime.InitializationException;
            } 
        }
 
        // called from app manager (from management APIs) 
        internal ApplicationInfo GetApplicationInfo() {
            return new ApplicationInfo(_appId, _appVirtualPath, _appPhysicalPath); 
        }

        //
        // Shutdown logic 
        //
        [PermissionSet(SecurityAction.Assert, Unrestricted = true)] 
        private void StopRegisteredObjects(bool immediate) { 
            if (_registeredObjects.Count > 0) {
                ArrayList list = new ArrayList(); 

                lock (this) {
                    foreach (DictionaryEntry e in _registeredObjects) {
                        Object x = e.Key; 

                        // well-known objects first 
                        if (IsWellKnownObject(x)) { 
                            list.Insert(0, x);
                        } 
                        else {
                            list.Add(x);
                        }
                    } 
                }
 
                foreach (IRegisteredObject obj in list) { 
                    try {
                        obj.Stop(immediate); 
                    }
                    catch {
                    }
                } 
            }
        } 
 
        private void InitiateShutdownWorkItemCallback(Object state /*not used*/) {
            Debug.Trace("HostingEnvironmentShutdown", "Shutting down: appId=" + _appId); 

            // no registered objects -- shutdown
            if (_registeredObjects.Count == 0) {
                Debug.Trace("HostingEnvironmentShutdown", "No registered objects"); 
                ShutdownThisAppDomainOnce();
                return; 
            } 

            // call Stop on all registered objects with immediate = false 
            StopRegisteredObjects(false);

            // no registered objects -- shutdown now
            if (_registeredObjects.Count == 0) { 
                Debug.Trace("HostingEnvironmentShutdown", "All registered objects gone after Stop(false)");
                ShutdownThisAppDomainOnce(); 
                return; 
            }
 
            // if not everything shutdown synchronously give it some time.
            int shutdownTimeoutSeconds = HostingEnvironmentSection.DefaultShutdownTimeout;
            HostingEnvironmentSection hostEnvConfig = RuntimeConfig.GetAppLKGConfig().HostingEnvironment;
            if (hostEnvConfig != null) { 
                shutdownTimeoutSeconds = (int) hostEnvConfig.ShutdownTimeout.TotalSeconds;
            } 
            Debug.Trace("HostingEnvironmentShutdown", "Waiting for " + shutdownTimeoutSeconds + " sec..."); 

            DateTime waitUntil = DateTime.UtcNow.AddSeconds(shutdownTimeoutSeconds); 
            while (_registeredObjects.Count > 0 && DateTime.UtcNow < waitUntil) {
                Thread.Sleep(100);
            }
 
            Debug.Trace("HostingEnvironmentShutdown", "Shutdown timeout (" + shutdownTimeoutSeconds + " sec) expired");
 
            // call Stop on all registered objects with immediate = true 
            StopRegisteredObjects(true);
 
            // no registered objects -- shutdown now
            if (_registeredObjects.Count == 0) {
                Debug.Trace("HostingEnvironmentShutdown", "All registered objects gone after Stop(true)");
                ShutdownThisAppDomainOnce(); 
                return;
            } 
 
            // shutdown regardless
            Debug.Trace("HostingEnvironmentShutdown", "Forced shutdown: " + _registeredObjects.Count + " registered objects left"); 
            _registeredObjects = new Hashtable();
            ShutdownThisAppDomainOnce();
        }
 
        // app domain shutdown logic
        internal void InitiateShutdownInternal() { 
            Debug.Trace("AppManager", "HostingEnvironment.InitiateShutdownInternal appId=" + _appId); 

            bool proceed = false; 

            if (!_shutdownInitiated) {
                lock (this) {
                    if (!_shutdownInitiated) { 
                        _shutdownInProgress = true;
                        proceed = true; 
                        _shutdownInitiated = true; 
                    }
                } 
            }

            if (!proceed) {
                return; 
            }
 
            HttpRuntime.SetShutdownReason(ApplicationShutdownReason.HostingEnvironment, "HostingEnvironment initiated shutdown"); 

            new EnvironmentPermission(PermissionState.Unrestricted).Assert(); 
            try {
                _shutDownStack = Environment.StackTrace;
            }
            finally { 
                CodeAccessPermission.RevertAssert();
            } 
 
            // this should only be called once, before the cache is disposed, and
            // the config records are released. 
            HttpRuntime.CoalesceNotifications();

            RemoveThisAppDomainFromAppManagerTableOnce();
 
            // stop all registered objects without blocking
            ThreadPool.QueueUserWorkItem(this._initiateShutdownWorkItemCallback); 
        } 

        internal bool HasBeenRemovedFromAppManagerTable { 
            get {
                return _hasBeenRemovedFromAppManangerTable;
            }
            set { 
                _hasBeenRemovedFromAppManangerTable = value;
            } 
        } 

        private void RemoveThisAppDomainFromAppManagerTableOnce() { 
            bool proceed = false;
            if (!_removedFromAppManager) {
                lock (this) {
                    if (!_removedFromAppManager) { 
                        proceed = true;
                        _removedFromAppManager = true; 
                    } 
                }
            } 

            if (!proceed)
                return;
 
            if (_appManager != null) {
                Debug.Trace("AppManager", "Removing HostingEnvironment from AppManager table, appId=" + _appId); 
                _appManager.HostingEnvironmentShutdownInitiated(_appId, this); 
            }
#if DBG 
            Debug.Trace("FileChangesMonitorIgnoreSubdirChange",
                        "*** REMOVE APPMANAGER TABLE" + DateTime.Now.ToString("hh:mm:ss.fff", CultureInfo.InvariantCulture)
                        + ": _appId=" + _appId);
#endif 
        }
 
        private void ShutdownThisAppDomainOnce() { 
            bool proceed = false;
 
            if (!_appDomainShutdownStarted) {
                lock (this) {
                    if (!_appDomainShutdownStarted) {
                        proceed = true; 
                        _appDomainShutdownStarted = true;
                    } 
                } 
            }
 
            if (!proceed)
                return;

            Debug.Trace("AppManager", "HostingEnvironment - shutting down AppDomain, appId=" + _appId); 

            // stop the timer used for idle timeout 
            if (_idleTimeoutMonitor != null) { 
                _idleTimeoutMonitor.Stop();
                _idleTimeoutMonitor = null; 
            }

            while (_inTrimCache == 1) {
                Thread.Sleep(100); 
            }
 
            // 
            HttpRuntime.SetUserForcedShutdown();
 
            //WOS 1400290: CantUnloadAppDomainException in ISAPI mode, wait until HostingEnvironment.ShutdownThisAppDomainOnce completes
            _shutdownInProgress = false;

            HttpRuntime.ShutdownAppDomainWithStackTrace(ApplicationShutdownReason.HostingEnvironment, 
                                                        SR.GetString(SR.Hosting_Env_Restart),
                                                        _shutDownStack); 
        } 

        // 
        // internal methods called by app manager
        //

        // helper for app manager to implement AppHost.CreateAppHost 
        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
        internal ObjectHandle CreateInstance(String assemblyQualifiedName) { 
            Type type = Type.GetType(assemblyQualifiedName, true); 
            return new ObjectHandle(Activator.CreateInstance(type));
        } 

        // start well known object
        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
        internal ObjectHandle CreateWellKnownObjectInstance(String assemblyQualifiedName, bool failIfExists) { 
            Type type = Type.GetType(assemblyQualifiedName, true);
            IRegisteredObject obj = null; 
            String key = type.FullName; 
            bool exists = false;
 
            lock (this) {
                obj = _wellKnownObjects[key] as IRegisteredObject;

                if (obj == null) { 
                    obj = (IRegisteredObject)Activator.CreateInstance(type);
                    _wellKnownObjects[key] = obj; 
                } 
                else {
                    exists = true; 
                }
            }

            if (exists && failIfExists) { 
                throw new InvalidOperationException(SR.GetString(SR.Wellknown_object_already_exists, key));
            } 
 
            return new ObjectHandle(obj);
        } 

        // check if well known object
        private bool IsWellKnownObject(Object obj) {
            bool found = false; 
            String key = obj.GetType().FullName;
 
            lock (this) { 
                if (_wellKnownObjects[key] == obj) {
                    found = true; 
                }
            }

            return found; 
        }
 
        // find well known object by type 
        internal ObjectHandle FindWellKnownObject(String assemblyQualifiedName) {
            Type type = Type.GetType(assemblyQualifiedName, true); 
            IRegisteredObject obj = null;
            String key = type.FullName;

            lock (this) { 
                obj = _wellKnownObjects[key] as IRegisteredObject;
            } 
 
            return (obj != null) ? new ObjectHandle(obj) : null;
        } 

        // stop well known object by type
        [PermissionSet(SecurityAction.Assert, Unrestricted = true)]
        internal void StopWellKnownObject(String assemblyQualifiedName) { 
            Type type = Type.GetType(assemblyQualifiedName, true);
            IRegisteredObject obj = null; 
            String key = type.FullName; 

            lock (this) { 
                obj = _wellKnownObjects[key] as IRegisteredObject;
                if (obj != null) {
                    _wellKnownObjects.Remove(key);
                    obj.Stop(false); 
                }
            } 
        } 

        internal bool IsIdle() { 
            bool isBusy = _isBusy;
            _isBusy = false;
            return (!isBusy && _busyCount == 0);
        } 

        internal bool GetIdleValue() { 
            return (!_isBusy && _busyCount == 0); 
        }
 
        internal void IncrementBusyCountInternal() {
            _isBusy = true;
            Interlocked.Increment(ref _busyCount);
        } 

        internal void DecrementBusyCountInternal() { 
            _isBusy = true; 
            Interlocked.Decrement(ref _busyCount);
 
            // Notify idle timeout monitor
            IdleTimeoutMonitor itm = _idleTimeoutMonitor;
            if (itm != null) {
                itm.LastEvent = DateTime.UtcNow; 
            }
        } 
        internal void IsUnloaded() 
        {
            return; 
        }

        private void MessageReceivedInternal() {
            _isBusy = true; 

            IdleTimeoutMonitor itm = _idleTimeoutMonitor; 
            if (itm != null) { 
                itm.LastEvent = DateTime.UtcNow;
            } 
        }

        // the busier the app domain the higher the score
        internal int LruScore { 
            get {
                if (_busyCount > 0) 
                    return _busyCount; 

                IdleTimeoutMonitor itm = _idleTimeoutMonitor; 

                if (itm == null)
                    return 0;
 
                // return negative number of seconds since last activity
                return -(int)(DateTime.UtcNow - itm.LastEvent).TotalSeconds; 
            } 
        }
 
        internal static ApplicationManager GetApplicationManager() {
            if (_theHostingEnvironment == null)
                return null;
 
            return _theHostingEnvironment._appManager;
        } 
 
        //
        // private helpers 
        //

        // register protocol handler with hosting environment
        private void RegisterRunningObjectInternal(IRegisteredObject obj) { 
            lock (this) {
                _registeredObjects[obj] = obj; 
            } 
        }
 
        // unregister protocol handler from hosting environment
        private void UnregisterRunningObjectInternal(IRegisteredObject obj) {
            bool lastOne = false;
 
            lock (this) {
                // if it is a well known object, remove it from that table as well 
                String key = obj.GetType().FullName; 
                if (_wellKnownObjects[key] == obj) {
                    _wellKnownObjects.Remove(key); 
                }

                // remove from running objects list
                _registeredObjects.Remove(obj); 

                if (_registeredObjects.Count == 0) 
                    lastOne = true; 
            }
 
            if (!lastOne)
                return;

            // shutdown app domain after last protocol handler is gone 

            InitiateShutdownInternal(); 
        } 

        // site name 
        private String GetSiteName() {
            if (_siteName == null) {
                lock (this) {
                    if (_siteName == null) { 
                        String s = null;
 
                        if (_appHost != null) { 
                            //
                            InternalSecurityPermissions.Unrestricted.Assert(); 
                            try {
                                s = _appHost.GetSiteName();
                            }
                            finally { 
                                CodeAccessPermission.RevertAssert();
                            } 
                        } 

                        if (s == null) 
                            s = WebConfigurationHost.DefaultSiteName;

                        _siteName = s;
                    } 
                }
            } 
 
            return _siteName;
        } 

        // site ID
        private String GetSiteID() {
            if (_siteID == null) { 
                lock (this) {
                    if (_siteID == null) { 
                        String s = null; 

                        if (_appHost != null) { 
                            //
                            InternalSecurityPermissions.Unrestricted.Assert();
                            try {
                                s = _appHost.GetSiteID(); 
                            }
                            finally { 
                                CodeAccessPermission.RevertAssert(); 
                            }
                        } 

                        if (s == null)
                            s = WebConfigurationHost.DefaultSiteID;
 
                        _siteID = s.ToLower(CultureInfo.InvariantCulture);
                    } 
                } 
            }
 
            return _siteID;
        }

        // Return the configPath for the app, e.g. "machine/webroot/1/myapp" 
        private String GetAppConfigPath() {
            if (_appConfigPath == null) { 
                _appConfigPath = WebConfigurationHost.GetConfigPathFromSiteIDAndVPath(SiteID, ApplicationVirtualPathObject); 
            }
 
            return _appConfigPath;
        }

        // Return the call context slot name to use for a virtual path 
        private static string GetFixedMappingSlotName(VirtualPath virtualPath) {
            return "MapPath_" + virtualPath.VirtualPathString.ToLowerInvariant().GetHashCode().ToString(CultureInfo.InvariantCulture); 
        } 

        /* 
         * Map a virtual path to a physical path.  i.e. the physicalPath will be returned
         * when MapPath is called on the virtual path, bypassing the IApplicationHost
         */
        private static string GetVirtualPathToFileMapping(VirtualPath virtualPath) { 
            return CallContext.GetData(GetFixedMappingSlotName(virtualPath)) as string;
        } 
 
        /*
         * Map a virtual path to a physical path.  i.e. the physicalPath will be returned 
         * when MapPath is called on the virtual path, bypassing the IApplicationHost
         */
        internal static object AddVirtualPathToFileMapping(
            VirtualPath virtualPath, string physicalPath) { 

            // Save the mapping in the call context, using a key derived from the 
            // virtual path.  The mapping is only valid for the duration of the request. 
            CallContext.SetData(GetFixedMappingSlotName(virtualPath), physicalPath);
 
            // Return a mapping object to keep track of the virtual path, and of the current
            // virtualPathProvider.
            VirtualPathToFileMappingState state = new VirtualPathToFileMappingState();
            state.VirtualPath = virtualPath; 
            state.VirtualPathProvider = _theHostingEnvironment._virtualPathProvider;
 
            // Always use the MapPathBasedVirtualPathProvider, otherwise the mapping mechanism 
            // doesn't work (VSWhidbey 420702)
            _theHostingEnvironment._virtualPathProvider = _theHostingEnvironment._mapPathBasedVirtualPathProvider; 

            return state;
        }
 
        internal static void ClearVirtualPathToFileMapping(object state) {
 
            VirtualPathToFileMappingState mapping = (VirtualPathToFileMappingState)state; 

            // Clear the mapping from the call context 
            CallContext.SetData(GetFixedMappingSlotName(mapping.VirtualPath), null);

            // Restore the previous VirtualPathProvider
            _theHostingEnvironment._virtualPathProvider = mapping.VirtualPathProvider; 
        }
 
        private string MapPathActual(VirtualPath virtualPath, bool permitNull) 
        {
            string result = null; 

            Debug.Assert(virtualPath != null);

            virtualPath.FailIfRelativePath(); 

            VirtualPath reqpath = virtualPath; 
 
            if (String.CompareOrdinal(reqpath.VirtualPathString, _appVirtualPath.VirtualPathString) == 0) {
                // for application path don't need to call app host 
                Debug.Trace("MapPath", reqpath  +" is the app path");
                result = _appPhysicalPath;
            }
            else { 
                using (new ProcessImpersonationContext()) {
                    // If there is a mapping for this virtual path in the call context, use it 
                    result = GetVirtualPathToFileMapping(reqpath); 

                    if (result == null) { 
                        // call host's mappath
                        if (_configMapPath == null) {
                            Debug.Trace("MapPath", "Missing _configMapPath");
                            throw new InvalidOperationException(SR.GetString(SR.Cannot_map_path, reqpath)); 
                        }
                        Debug.Trace("MapPath", "call ConfigMapPath (" + reqpath + ")"); 
 
                        // see if the IConfigMapPath provider implements the interface
                        // with VirtualPath 
                        try {
                            if (null != _configMapPath2) {
                                result = _configMapPath2.MapPath(GetSiteID(), reqpath);
                            } 
                            else {
                                result = _configMapPath.MapPath(GetSiteID(), reqpath.VirtualPathString); 
                            } 
                            if (HttpRuntime.IsMapPathRelaxed)
                                result = HttpRuntime.GetRelaxedMapPathResult(result); 
                        } catch {
                            if (HttpRuntime.IsMapPathRelaxed)
                                result = HttpRuntime.GetRelaxedMapPathResult(null);
                            else 
                                throw;
                        } 
                    } 
                }
            } 

            if (String.IsNullOrEmpty(result)) {
                Debug.Trace("MapPath", "null Result");
                if (!permitNull) { 
                    if (HttpRuntime.IsMapPathRelaxed)
                        result = HttpRuntime.GetRelaxedMapPathResult(null); 
                    else 
                        throw new InvalidOperationException(SR.GetString(SR.Cannot_map_path, reqpath));
                } 
            }
            else {
                // ensure extra '\\' in the physical path if the virtual path had extra '/'
                // and the other way -- no extra '\\' in physical if virtual didn't have it. 
                if (virtualPath.HasTrailingSlash) {
                    if (!UrlPath.PathEndsWithExtraSlash(result) && !UrlPath.PathIsDriveRoot(result)) 
                        result = result + "\\"; 
                }
                else { 
                    if (UrlPath.PathEndsWithExtraSlash(result) && !UrlPath.PathIsDriveRoot(result))
                        result = result.Substring(0, result.Length - 1);
                }
 
                Debug.Trace("MapPath", "    result=" + result);
            } 
 
            return result;
        } 

        //
        // public static methods
        // 

 
        // register protocol handler with hosting environment 
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
        public static void RegisterObject(IRegisteredObject obj) { 
            if (_theHostingEnvironment != null)
                _theHostingEnvironment.RegisterRunningObjectInternal(obj);
        }
 

        // unregister protocol handler from hosting environment 
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)] 
        public static void UnregisterObject(IRegisteredObject obj) {
            if (_theHostingEnvironment != null) 
                _theHostingEnvironment.UnregisterRunningObjectInternal(obj);
        }

        // 
        // public static methods for the user code to call
        // 
 

        public static void IncrementBusyCount() { 
            if (_theHostingEnvironment != null)
                _theHostingEnvironment.IncrementBusyCountInternal();
        }
 

        public static void DecrementBusyCount() { 
            if (_theHostingEnvironment != null) 
                _theHostingEnvironment.DecrementBusyCountInternal();
        } 


        public static void MessageReceived() {
            if (_theHostingEnvironment != null) 
                _theHostingEnvironment.MessageReceivedInternal();
        } 
 
        public static bool InClientBuildManager {
            get { 
                return BuildManagerHost.InClientBuildManager;
            }
        }
 
        public static bool IsHosted {
            get { 
                return (_theHostingEnvironment != null); 
            }
        } 

        internal static bool IsUnderIISProcess {
            get {
                String process = VersionInfo.ExeName; 

                return process == "aspnet_wp" || 
                       process == "w3wp" || 
                       process == "inetinfo";
            } 
        }

        internal static bool IsUnderIIS6Process {
            get { 
                return VersionInfo.ExeName == "w3wp";
            } 
        } 

        public static IApplicationHost ApplicationHost { 
            //DevDivBugs 109864: ASP.NET: path discovery issue - In low trust, it is possible to get the physical path of any virtual path on the machine
            [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
            get {
                if (_theHostingEnvironment == null) 
                    return null;
 
                return _theHostingEnvironment._appHost; 
            }
        } 

       internal static IApplicationHost ApplicationHostInternal {
            get {
                if (_theHostingEnvironment == null) 
                    return null;
 
                return _theHostingEnvironment._appHost; 
            }
        } 

        internal IApplicationHost InternalApplicationHost {
            get {
                return _appHost; 
            }
        } 
 
        internal static int BusyCount {
            get { 
                if (_theHostingEnvironment == null)
                    return 0;

                return _theHostingEnvironment._busyCount; 
            }
        } 
 
        internal static bool ShutdownInitiated {
            get { 
                if (_theHostingEnvironment == null)
                    return false;

                return _theHostingEnvironment._shutdownInitiated; 
            }
        } 
 

        internal static bool ShutdownInProgress { 
            get {
                if (_theHostingEnvironment == null)
                    return false;
 
                return _theHostingEnvironment._shutdownInProgress;
            } 
        } 

 
        /// 
        ///    The application ID (metabase path in IIS hosting).
        /// 
        public static String ApplicationID { 
            get {
                if (_theHostingEnvironment == null) 
                    return null; 

                InternalSecurityPermissions.AspNetHostingPermissionLevelHigh.Demand(); 
                return _theHostingEnvironment._appId;
            }
        }
 
        internal static String ApplicationIDNoDemand {
            get { 
                if (_theHostingEnvironment == null) { 
                    return null;
                } 

                return _theHostingEnvironment._appId;
            }
        } 

 
        ///  
        ///    Physical path to the application root.
        ///  
        public static String ApplicationPhysicalPath {
            get {
                if (_theHostingEnvironment == null)
                    return null; 

                InternalSecurityPermissions.AppPathDiscovery.Demand(); 
                return _theHostingEnvironment._appPhysicalPath; 
            }
        } 


        /// 
        ///    Virtual path to the application root. 
        /// 
        public static String ApplicationVirtualPath { 
            get { 
                return VirtualPath.GetVirtualPathStringNoTrailingSlash(ApplicationVirtualPathObject);
            } 
        }

        internal static VirtualPath ApplicationVirtualPathObject {
            get { 
                if (_theHostingEnvironment == null)
                    return null; 
 
                return _theHostingEnvironment._appVirtualPath;
            } 
        }


        ///  
        ///    Site name.
        ///  
        public static String SiteName { 
            get {
                if (_theHostingEnvironment == null) 
                    return null;

                InternalSecurityPermissions.AspNetHostingPermissionLevelMedium.Demand();
                return _theHostingEnvironment.GetSiteName(); 
            }
        } 
 
        internal static String SiteNameNoDemand {
            get { 
                if (_theHostingEnvironment == null)
                    return null;

                return _theHostingEnvironment.GetSiteName(); 
            }
        } 
 
        internal static String SiteID {
            get { 
                if (_theHostingEnvironment == null)
                    return null;

                return _theHostingEnvironment.GetSiteID(); 
            }
        } 
 
        internal static IConfigMapPath ConfigMapPath {
            get { 
                if (_theHostingEnvironment == null)
                    return null;

                return _theHostingEnvironment._configMapPath; 
            }
        } 
 
        internal static String AppConfigPath {
            get { 
                if (_theHostingEnvironment == null) {
                    return null;
                }
 
                return _theHostingEnvironment.GetAppConfigPath();
            } 
        } 

 
        /// 
        ///    
        ///       Gets a reference to the System.Web.Cache.Cache object for the current request.
        ///     
        /// 
        public static Cache Cache { 
            get { return HttpRuntime.Cache; } 
        }
 
        // count of all app domain from app manager
        internal static int AppDomainsCount {
            get {
                ApplicationManager appManager = GetApplicationManager(); 
                return (appManager != null) ? appManager.AppDomainsCount : 0;
            } 
        } 

        internal static HostingEnvironmentParameters HostingParameters { 
            get {
                if (_theHostingEnvironment == null)
                    return null;
 
                return _theHostingEnvironment._hostingParameters;
            } 
        } 

        // Return an integer that is unique for each appdomain.  This can be used 
        // to create things like once-per-appdomain temp files without having different
        // processes/appdomains step on each other
        private static int s_appDomainUniqueInteger;
        internal static int AppDomainUniqueInteger { 
            get {
                if (s_appDomainUniqueInteger == 0) { 
                    s_appDomainUniqueInteger = Guid.NewGuid().GetHashCode(); 
                }
 
                return s_appDomainUniqueInteger;
            }
        }
 
        public static ApplicationShutdownReason ShutdownReason {
            get { return HttpRuntime.ShutdownReason; } 
        } 

        ///  
        ///    Initiate app domain unloading for the current app.
        /// 
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
        public static void InitiateShutdown() { 
            if (_theHostingEnvironment != null)
                _theHostingEnvironment.InitiateShutdownInternal(); 
        } 

        internal static void InitiateShutdownWithoutDemand() { 
            if (_theHostingEnvironment != null)
                _theHostingEnvironment.InitiateShutdownInternal();
        }
 
        /// 
        ///    Maps a virtual path to a physical path. 
        ///  
        public static string MapPath(string virtualPath) {
            return MapPath(VirtualPath.Create(virtualPath)); 
        }

        internal static string MapPath(VirtualPath virtualPath) {
            if (_theHostingEnvironment == null) 
                return null;
 
            String path = MapPathInternal(virtualPath); 

            if (path != null) 
                InternalSecurityPermissions.PathDiscovery(path).Demand();

            return path;
        } 

        internal static String MapPathInternal(string virtualPath) { 
            return MapPathInternal(VirtualPath.Create(virtualPath)); 
        }
 
        internal static String MapPathInternal(VirtualPath virtualPath) {
            if (_theHostingEnvironment == null) {
                return null;
            } 

            return _theHostingEnvironment.MapPathActual(virtualPath, false); 
        } 

        internal static String MapPathInternal(string virtualPath, bool permitNull) { 
            return MapPathInternal(VirtualPath.Create(virtualPath), permitNull);
        }

        internal static String MapPathInternal(VirtualPath virtualPath, bool permitNull) { 
            if (_theHostingEnvironment == null) {
                return null; 
            } 

            return _theHostingEnvironment.MapPathActual(virtualPath, permitNull); 
        }

        internal static string MapPathInternal(string virtualPath, string baseVirtualDir, bool allowCrossAppMapping) {
            return MapPathInternal(VirtualPath.Create(virtualPath), 
                VirtualPath.CreateNonRelative(baseVirtualDir), allowCrossAppMapping);
        } 
 
        internal static string MapPathInternal(VirtualPath virtualPath, VirtualPath baseVirtualDir, bool allowCrossAppMapping) {
            Debug.Assert(baseVirtualDir != null, "baseVirtualDir != null"); 

            // Combine it with the base and reduce
            virtualPath = baseVirtualDir.Combine(virtualPath);
 
            if (!allowCrossAppMapping && !virtualPath.IsWithinAppRoot)
                throw new ArgumentException(SR.GetString(SR.Cross_app_not_allowed, virtualPath)); 
 
            return MapPathInternal(virtualPath);
        } 

        internal static WebApplicationLevel GetPathLevel(String path) {
            WebApplicationLevel pathLevel = WebApplicationLevel.AboveApplication;
 
            if (_theHostingEnvironment != null && !String.IsNullOrEmpty(path)) {
                String appPath = ApplicationVirtualPath; 
 
                if (appPath == "/") {
                    if (path == "/") { 
                        pathLevel = WebApplicationLevel.AtApplication;
                    }
                    else if (path[0] == '/') {
                        pathLevel = WebApplicationLevel.BelowApplication; 
                    }
                } 
                else { 
                    if (StringUtil.EqualsIgnoreCase(appPath, path)) {
                        pathLevel = WebApplicationLevel.AtApplication; 
                    }
                    else if (path.Length > appPath.Length && path[appPath.Length] == '/' &&
                        StringUtil.StringStartsWithIgnoreCase(path, appPath)) {
 
                        pathLevel = WebApplicationLevel.BelowApplication;
                    } 
                } 
            }
 
            return pathLevel;
        }

 
        //
        // Impersonation helpers 
        // 
        // user token for the app (hosting / unc)
        internal static IntPtr ApplicationIdentityToken { 
            get {
                if (_theHostingEnvironment == null) {
                    return IntPtr.Zero;
                } 
                else {
                    if (_theHostingEnvironment._appIdentityTokenSet) 
                        return _theHostingEnvironment._appIdentityToken; 
                    else
                        return _theHostingEnvironment._configToken; 
                }
            }
        }
 

        // check if application impersonation != process impersonation 
        internal static bool HasHostingIdentity { 
            get {
                return (ApplicationIdentityToken != IntPtr.Zero); 
            }
        }

        // impersonate application identity 
        [SecurityPermission(SecurityAction.Demand, ControlPrincipal = true)]
        public static IDisposable Impersonate() { 
            return new ApplicationImpersonationContext(); 
        }
 
        // impersonate the given user identity
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)]
        public static IDisposable Impersonate(IntPtr token) {
            if (token == IntPtr.Zero) { 
                return new ProcessImpersonationContext();
            } 
            else { 
                return new ImpersonationContext(token);
            } 
        }

        // impersonate as configured for a given path
        [SecurityPermission(SecurityAction.Demand, Unrestricted = true)] 
        public static IDisposable Impersonate(IntPtr userToken, String virtualPath) {
            virtualPath = UrlPath.MakeVirtualPathAppAbsoluteReduceAndCheck(virtualPath); 
 
            if (_theHostingEnvironment == null) {
                return Impersonate(userToken); 
            }

            IdentitySection c = RuntimeConfig.GetConfig(virtualPath).Identity;
            if (c.Impersonate) { 
                if (c.ImpersonateToken != IntPtr.Zero) {
                    return new ImpersonationContext(c.ImpersonateToken); 
                } 
                else {
                    return new ImpersonationContext(userToken); 
                }
            }
            else {
                return new ApplicationImpersonationContext(); 
            }
        } 
 
        //
        //  Culture helpers 
        //

        public static IDisposable SetCultures() {
            return SetCultures(RuntimeConfig.GetAppLKGConfig().Globalization); 
        }
 
        public static IDisposable SetCultures(string virtualPath) { 
            virtualPath = UrlPath.MakeVirtualPathAppAbsoluteReduceAndCheck(virtualPath);
            return SetCultures(RuntimeConfig.GetConfig(virtualPath).Globalization); 
        }

        private static IDisposable SetCultures(GlobalizationSection gs) {
            CultureContext c = new CultureContext(); 

            if (gs != null) { 
                CultureInfo culture = null; 
                CultureInfo uiCulture = null;
 
                if (gs.Culture != null && gs.Culture.Length > 0) {
                    try {
                        culture = HttpServerUtility.CreateReadOnlyCultureInfo(gs.Culture);
                    } 
                    catch {
                    } 
                } 

                if (gs.UICulture != null && gs.UICulture.Length > 0) { 
                    try {
                        uiCulture = HttpServerUtility.CreateReadOnlyCultureInfo(gs.UICulture);
                    }
                    catch { 
                    }
                } 
 
                c.SetCultures(culture, uiCulture);
            } 

            return c;
        }
 

        class CultureContext : IDisposable { 
            CultureInfo _savedCulture; 
            CultureInfo _savedUICulture;
 
            internal CultureContext() {
            }

            void IDisposable.Dispose() { 
                RestoreCultures();
            } 
 
            internal void SetCultures(CultureInfo culture, CultureInfo uiCulture) {
                CultureInfo currentCulture = Thread.CurrentThread.CurrentCulture; 
                CultureInfo currentUICulture = Thread.CurrentThread.CurrentUICulture;

                if (culture != null && culture != currentCulture) {
                    Thread.CurrentThread.CurrentCulture = culture; 
                    _savedCulture = currentCulture;
                } 
 
                if (uiCulture != null && uiCulture != currentCulture) {
                    Thread.CurrentThread.CurrentUICulture = uiCulture; 
                    _savedUICulture = currentUICulture;
                }
            }
 
            internal void RestoreCultures() {
                if (_savedCulture != null && _savedCulture != Thread.CurrentThread.CurrentCulture) { 
                    Thread.CurrentThread.CurrentCulture = _savedCulture; 
                    _savedCulture = null;
                } 

                if (_savedUICulture != null && _savedUICulture != Thread.CurrentThread.CurrentUICulture) {
                    Thread.CurrentThread.CurrentUICulture = _savedUICulture;
                    _savedUICulture = null; 
                }
            } 
        } 

        // 
        // VirtualPathProvider related code
        //

        private VirtualPathProvider _virtualPathProvider; 
        private VirtualPathProvider _mapPathBasedVirtualPathProvider;
 
 
        public static VirtualPathProvider VirtualPathProvider {
            get { 
                if (_theHostingEnvironment == null)
                    return null;

                return _theHostingEnvironment._virtualPathProvider; 
            }
        } 
 
        internal static bool UsingMapPathBasedVirtualPathProvider {
            get { 
                if (_theHostingEnvironment == null)
                    return true;

                return (_theHostingEnvironment._virtualPathProvider == 
                    _theHostingEnvironment._mapPathBasedVirtualPathProvider);
            } 
        } 

        // [AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.High)] 
        // Removed the above LinkDemand for AspNetHostingPermissionLevel.High. If we decide to add VPP
        // support for config in the future, we should have a separate API with a demand for registering
        // VPPs supporting configuration.
        public static void RegisterVirtualPathProvider(VirtualPathProvider virtualPathProvider) { 

            if (_theHostingEnvironment == null) 
                throw new InvalidOperationException(); 

            // Ignore the VirtualPathProvider on precompiled sites (VSWhidbey 368169,404844) 
            if (BuildManager.IsPrecompiledApp)
                return;

            RegisterVirtualPathProviderInternal(virtualPathProvider); 
        }
 
        internal static void RegisterVirtualPathProviderInternal(VirtualPathProvider virtualPathProvider) { 
            VirtualPathProvider previous = _theHostingEnvironment._virtualPathProvider;
            _theHostingEnvironment._virtualPathProvider = virtualPathProvider; 

            // Give it the previous provider so it can delegate if needed
            virtualPathProvider.Initialize(previous);
        } 

        // Helper class used to keep track of state when using 
        // AddVirtualPathToFileMapping & ClearVirtualPathToFileMapping 
        internal class VirtualPathToFileMappingState {
            internal VirtualPath VirtualPath; 
            internal VirtualPathProvider VirtualPathProvider;
        }

        internal static IProcessHostSupportFunctions SupportFunctions { 
            get {
                return _functions; 
            } 
            set {
                _functions = value; 
            }
        }

        [SuppressMessage("Microsoft.Naming", "CA1705:LongAcronymsShouldBePascalCased", 
                         Justification="matches casing of config attribute")]
        public static int MaxConcurrentRequestsPerCPU { 
            get { 
                if (!HttpRuntime.UseIntegratedPipeline) {
                    throw new PlatformNotSupportedException(SR.GetString(SR.Requires_Iis_Integrated_Mode)); 
                }
                return UnsafeIISMethods.MgdGetMaxConcurrentRequestsPerCPU();
            }
            [SecurityPermission(SecurityAction.Demand, Unrestricted = true)] 
            set {
                if (!HttpRuntime.UseIntegratedPipeline) { 
                    throw new PlatformNotSupportedException(SR.GetString(SR.Requires_Iis_Integrated_Mode)); 
                }
                int hr = UnsafeIISMethods.MgdSetMaxConcurrentRequestsPerCPU(value); 
                switch (hr) {
                    case HResults.S_FALSE:
                        // Because "maxConcurrentRequestsPerCPU" is currently zero, we cannot set the value, since that would
                        // enable the feature, which can only be done via configuration. 
                        throw new InvalidOperationException(SR.GetString(SR.Queue_limit_is_zero, "maxConcurrentRequestsPerCPU"));
                    case HResults.E_INVALIDARG: 
                        // The value must be greater than zero.  A value of zero would disable the feature, but this can only be done via configuration. 
                        throw new ArgumentException(SR.GetString(SR.Invalid_queue_limit));
                } 
            }
        }

        [SuppressMessage("Microsoft.Naming", "CA1705:LongAcronymsShouldBePascalCased", 
                         Justification="matches casing of config attribute")]
        public static int MaxConcurrentThreadsPerCPU { 
            get { 
                if (!HttpRuntime.UseIntegratedPipeline) {
                    throw new PlatformNotSupportedException(SR.GetString(SR.Requires_Iis_Integrated_Mode)); 
                }
                return UnsafeIISMethods.MgdGetMaxConcurrentThreadsPerCPU();
            }
            [SecurityPermission(SecurityAction.Demand, Unrestricted = true)] 
            set {
                if (!HttpRuntime.UseIntegratedPipeline) { 
                    throw new PlatformNotSupportedException(SR.GetString(SR.Requires_Iis_Integrated_Mode)); 
                }
                int hr = UnsafeIISMethods.MgdSetMaxConcurrentThreadsPerCPU(value); 
                switch (hr) {
                    case HResults.S_FALSE:
                        // Because "maxConcurrentThreadsPerCPU" is currently zero, we cannot set the value, since that would
                        // enable the feature, which can only be done via configuration. 
                        throw new InvalidOperationException(SR.GetString(SR.Queue_limit_is_zero, "maxConcurrentThreadsPerCPU"));
                    case HResults.E_INVALIDARG: 
                        // The value must be greater than zero.  A value of zero would disable the feature, but this can only be done via configuration. 
                        throw new ArgumentException(SR.GetString(SR.Invalid_queue_limit));
                } 
            }
        }

        ///  
        /// Returns the ASP.NET hosted domain.
        ///  
        internal AppDomain HostedAppDomain { 
            get {
                return AppDomain.CurrentDomain; 
            }
        }

    } 
}
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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