mcs/class/System.Web/System.Web/HttpApplicationFactory.cs

   1 //
   2 // System.Web.HttpApplicationFactory
   3 //
   4 // Author:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //
   7 // (c) 2002,2003 Ximian, Inc. (http://www.ximian.com)
   8 // (c) Copyright 2004 Novell, Inc. (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29 using System;
  30 using System.Collections;
  31 using System.IO;
  32 using System.Reflection;
  33 using System.Web.UI;
  34 using System.Web.SessionState;
  35 using System.Web.Configuration;
  36
  37 using System.Web.Compilation;
  38 #if TARGET_J2EE
  39 using vmw.common;
  40 #endif
  41
  42 #if NET_2_0 && !TARGET_J2EE
  43 using System.CodeDom.Compiler;
  44 #endif
  45
  46 namespace System.Web {
  47         class HttpApplicationFactory {
  48                 object this_lock = new object ();
  49
  50                 // Initialized in InitType
  51 #if TARGET_J2EE
  52                 static HttpApplicationFactory theFactory {
  53                         get
  54                         {
  55                                 HttpApplicationFactory factory = (HttpApplicationFactory)AppDomain.CurrentDomain.GetData("HttpApplicationFactory");
  56                                 if (factory == null) {
  57                                         lock(typeof(HttpApplicationFactory)) {
  58                                                 factory = (HttpApplicationFactory)AppDomain.CurrentDomain.GetData("HttpApplicationFactory");
  59                                                 if (factory == null) {
  60                                                         factory = new HttpApplicationFactory();
  61                                                         System.Threading.Thread.Sleep(1);
  62                                                         AppDomain.CurrentDomain.SetData("HttpApplicationFactory", factory);
  63                                                 }
  64                                         }
  65                                 }
  66                                 return factory;
  67                         }
  68                 }
  69 #else
  70                 static HttpApplicationFactory theFactory = new HttpApplicationFactory();
  71 #endif
  72                 MethodInfo session_end;
  73                 bool needs_init = true;
  74                 bool app_start_needed = true;
  75                 Type app_type;
  76                 HttpApplicationState app_state;
  77                 Hashtable app_event_handlers;
  78                 static ArrayList watchers = new ArrayList();
  79                 static object watchers_lock = new object();
  80                 static bool app_shutdown = false;
  81 #if NET_2_0
  82                 static bool app_disabled = false;
  83                 static string[] app_browsers_files = new string[0];
  84 #endif
  85                 Stack available = new Stack ();
  86                 Stack available_for_end = new Stack ();
  87
  88                 bool IsEventHandler (MethodInfo m)
  89                 {
  90                         int pos = m.Name.IndexOf ('_');
  91                         if (pos == -1 || (m.Name.Length - 1) <= pos)
  92                                 return false;
  93
  94                         if (m.ReturnType != typeof (void))
  95                                 return false;
  96
  97                         ParameterInfo [] pi = m.GetParameters ();
  98                         int length = pi.Length;
  99                         if (length == 0)
 100                                 return true;
 101
 102                         if (length != 2)
 103                                 return false;
 104
 105                         if (pi [0].ParameterType != typeof (object) ||
 106                             pi [1].ParameterType != typeof (EventArgs))
 107                                 return false;
 108
 109                         return true;
 110                 }
 111
 112                 void AddEvent (MethodInfo method, Hashtable appTypeEventHandlers)
 113                 {
 114                         string name = method.Name.Replace ("_On", "_");
 115                         if (appTypeEventHandlers [name] == null) {
 116                                 appTypeEventHandlers [name] = method;
 117                                 return;
 118                         }
 119
 120                         MethodInfo old_method = appTypeEventHandlers [name] as MethodInfo;
 121                         ArrayList list;
 122                         if (old_method != null){
 123                                 list = new ArrayList (4);
 124                                 list.Add (old_method);
 125                                 appTypeEventHandlers [name] = list;
 126                         } else
 127                                 list = appTypeEventHandlers [name] as ArrayList;
 128
 129                         list.Add (method);
 130                 }
 131
 132                 ArrayList GetMethodsDeep (Type type)
 133                 {
 134                         ArrayList al = new ArrayList ();
 135                         MethodInfo[] methods = type.GetMethods (BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance  | BindingFlags.Static | BindingFlags.FlattenHierarchy);
 136                         al.AddRange (methods);
 137
 138                         Type t = type.BaseType;
 139                         while (t != null) {
 140                                 methods = t.GetMethods (BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
 141                                 al.AddRange (methods);
 142                                 t = t.BaseType;
 143                         }
 144
 145                         return al;
 146                 }
 147
 148                 Hashtable GetApplicationTypeEvents (Type type)
 149                 {
 150                         lock (this_lock) {
 151                                 if (app_event_handlers != null)
 152                                         return app_event_handlers;
 153
 154                                 app_event_handlers = new Hashtable ();
 155                                 ArrayList methods = GetMethodsDeep (type);
 156                                 Hashtable used = null;
 157                                 MethodInfo m;
 158                                 string mname;
 159
 160                                 foreach (object o in methods) {
 161                                         m = o as MethodInfo;
 162                                         if (m.DeclaringType != typeof (HttpApplication) && IsEventHandler (m)) {
 163                                                 mname = m.ToString ();
 164                                                 if (used == null)
 165                                                         used = new Hashtable ();
 166                                                 else if (used.ContainsKey (mname))
 167                                                         continue;
 168                                                 used.Add (mname, m);
 169                                                 AddEvent (m, app_event_handlers);
 170                                         }
 171                                 }
 172                                 used = null;
 173                         }
 174
 175                         return app_event_handlers;
 176                 }
 177
 178                 Hashtable GetApplicationTypeEvents (HttpApplication app)
 179                 {
 180                         lock (this_lock) {
 181                                 if (app_event_handlers != null)
 182                                         return app_event_handlers;
 183
 184                                 return GetApplicationTypeEvents (app.GetType ());
 185                         }
 186                 }
 187
 188                 bool FireEvent (string method_name, object target, object [] args)
 189                 {
 190                         Hashtable possibleEvents = GetApplicationTypeEvents ((HttpApplication) target);
 191                         MethodInfo method = possibleEvents [method_name] as MethodInfo;
 192                         if (method == null)
 193                                 return false;
 194
 195                         if (method.GetParameters ().Length == 0)
 196                                 args = null;
 197
 198                         method.Invoke (target, args);
 199
 200                         return true;
 201                 }
 202
 203                 HttpApplication FireOnAppStart (HttpContext context)
 204                 {
 205                         HttpApplication app = (HttpApplication) Activator.CreateInstance (app_type, true);
 206                         context.ApplicationInstance = app;
 207                         app.SetContext (context);
 208                         object [] args = new object [] {app, EventArgs.Empty};
 209                         app.InApplicationStart = true;
 210                         FireEvent ("Application_Start", app, args);
 211                         app.InApplicationStart = false;
 212                         return app;
 213                 }
 214
 215                 void FireOnAppEnd ()
 216                 {
 217                         if (app_type == null)
 218                                 return; // we didn't even get an application
 219
 220                         HttpApplication app = (HttpApplication) Activator.CreateInstance (app_type, true);
 221                         FireEvent ("Application_End", app, new object [] {new object (), EventArgs.Empty});
 222                         app.DisposeInternal ();
 223                         app_type = null;
 224                 }
 225
 226                 //
 227                 // This is invoked by HttpRuntime.Dispose, when we unload an AppDomain
 228                 // To reproduce this in action, touch "global.asax" while XSP is running.
 229                 //
 230                 public static void Dispose ()
 231                 {
 232                         theFactory.FireOnAppEnd ();
 233                 }
 234
 235                 static FileSystemWatcher CreateWatcher (string file, FileSystemEventHandler hnd, RenamedEventHandler reh)
 236                 {
 237                         FileSystemWatcher watcher = new FileSystemWatcher ();
 238
 239                         watcher.Path = Path.GetFullPath (Path.GetDirectoryName (file));
 240                         watcher.Filter = Path.GetFileName (file);
 241
 242                         // This will enable the Modify flag for Linux/inotify
 243                         watcher.NotifyFilter |= NotifyFilters.Size;
 244
 245                         watcher.Changed += hnd;
 246                         watcher.Created += hnd;
 247                         watcher.Deleted += hnd;
 248                         watcher.Renamed += reh;
 249
 250                         watcher.EnableRaisingEvents = true;
 251
 252                         return watcher;
 253                 }
 254
 255                 internal static void AttachEvents (HttpApplication app)
 256                 {
 257                         HttpApplicationFactory factory = theFactory;
 258                         Hashtable possibleEvents = factory.GetApplicationTypeEvents (app);
 259                         foreach (string key in possibleEvents.Keys) {
 260                                 int pos = key.IndexOf ('_');
 261                                 string moduleName = key.Substring (0, pos);
 262                                 object target;
 263                                 if (moduleName == "Application") {
 264                                         target = app;
 265                                 } else {
 266                                         target = app.Modules [moduleName];
 267                                         if (target == null)
 268                                                 continue;
 269                                 }
 270
 271                                 string eventName = key.Substring (pos + 1);
 272                                 EventInfo evt = target.GetType ().GetEvent (eventName);
 273                                 if (evt == null)
 274                                         continue;
 275
 276                                 string usualName = moduleName + "_" + eventName;
 277                                 object methodData = possibleEvents [usualName];
 278                                 if (methodData != null && eventName == "End" && moduleName == "Session") {
 279                                         lock (factory) {
 280                                                 if (factory.session_end == null)
 281                                                         factory.session_end = (MethodInfo) methodData;
 282                                         }
 283                                         continue;
 284                                 }
 285
 286                                 if (methodData == null)
 287                                         continue;
 288
 289                                 if (methodData is MethodInfo) {
 290                                         factory.AddHandler (evt, target, app, (MethodInfo) methodData);
 291                                         continue;
 292                                 }
 293
 294                                 ArrayList list = (ArrayList) methodData;
 295                                 foreach (MethodInfo method in list)
 296                                         factory.AddHandler (evt, target, app, method);
 297                         }
 298                 }
 299
 300                 void AddHandler (EventInfo evt, object target, HttpApplication app, MethodInfo method)
 301                 {
 302                         int length = method.GetParameters ().Length;
 303
 304                         if (length == 0) {
 305                                 NoParamsInvoker npi = new NoParamsInvoker (app, method);
 306                                 evt.AddEventHandler (target, npi.FakeDelegate);
 307                         } else {
 308                                 if (method.IsStatic) {
 309                                         evt.AddEventHandler (target, Delegate.CreateDelegate (
 310                                                 evt.EventHandlerType, method));
 311                                 } else {
 312                                         evt.AddEventHandler (target, Delegate.CreateDelegate (
 313                                                                      evt.EventHandlerType, app,
 314 #if NET_2_0
 315                                                                      method
 316 #else
 317                                                                      method.Name
 318 #endif
 319                                                              ));
 320                                 }
 321                         }
 322
 323                 }
 324
 325                 internal static void InvokeSessionEnd (object state)
 326                 {
 327                         InvokeSessionEnd (state, null, EventArgs.Empty);
 328                 }
 329
 330                 internal static void InvokeSessionEnd (object state, object source, EventArgs e)
 331                 {
 332                         HttpApplicationFactory factory = theFactory;
 333                         MethodInfo method = null;
 334                         HttpApplication app = null;
 335                         lock (factory.available_for_end) {
 336                                 method = factory.session_end;
 337                                 if (method == null)
 338                                         return;
 339
 340                                 app = GetApplicationForSessionEnd ();
 341                         }
 342
 343                         app.SetSession ((HttpSessionState) state);
 344                         try {
 345                                 method.Invoke (app, new object [] {(source == null ? app : source), e});
 346                         } catch (Exception) {
 347                                 // Ignore
 348                         }
 349                         RecycleForSessionEnd (app);
 350                 }
 351
 352                 static HttpStaticObjectsCollection MakeStaticCollection (ArrayList list)
 353                 {
 354                         if (list == null || list.Count == 0)
 355                                 return null;
 356
 357                         HttpStaticObjectsCollection coll = new HttpStaticObjectsCollection ();
 358                         foreach (ObjectTagBuilder tag in list) {
 359                                 coll.Add (tag);
 360                         }
 361
 362                         return coll;
 363                 }
 364
 365                 internal static HttpApplicationState ApplicationState {
 366 #if TARGET_J2EE
 367                         get {
 368                                 HttpApplicationFactory factory = theFactory;
 369                                 if (factory.app_state == null)
 370                                         factory.app_state = new HttpApplicationState (null, null);
 371                                 return factory.app_state;
 372                         }
 373 #else
 374                         get {
 375                                 if (theFactory.app_state == null) {
 376                                         HttpStaticObjectsCollection app = MakeStaticCollection (GlobalAsaxCompiler.ApplicationObjects);
 377                                         HttpStaticObjectsCollection ses = MakeStaticCollection (GlobalAsaxCompiler.SessionObjects);
 378
 379                                         theFactory.app_state = new HttpApplicationState (app, ses);
 380                                 }
 381                                 return theFactory.app_state;
 382                         }
 383 #endif
 384                 }
 385
 386                 internal static Type AppType {
 387                         get {
 388                                 return theFactory.app_type;
 389                         }
 390                 }
 391
 392                 void InitType (HttpContext context)
 393                 {
 394                         lock (this_lock) {
 395                                 if (!needs_init)
 396                                         return;
 397
 398 #if NET_2_0
 399                                 try {
 400 #endif
 401                                         string physical_app_path = HttpRuntime.AppDomainAppPath;
 402                                         string app_file = null;
 403
 404                                         app_file = Path.Combine (physical_app_path, "Global.asax");
 405                                         if (!File.Exists (app_file)) {
 406                                                 app_file = Path.Combine (physical_app_path, "global.asax");
 407                                                 if (!File.Exists (app_file))
 408                                                         app_file = null;
 409                                         }
 410
 411 #if !NET_2_0
 412                                         WebConfigurationSettings.Init (context);
 413 #endif
 414
 415 #if NET_2_0 && !TARGET_J2EE
 416                                         AppResourcesCompiler ac = new AppResourcesCompiler (context);
 417                                         ac.Compile ();
 418
 419 #if WEBSERVICES_DEP
 420                                         AppWebReferencesCompiler awrc = new AppWebReferencesCompiler ();
 421                                         awrc.Compile ();
 422 #endif
 423
 424                                         // Todo: Generate profile properties assembly from Web.config here
 425
 426                                         AppCodeCompiler acc = new AppCodeCompiler ();
 427                                         acc.Compile ();
 428
 429                                         // Note whether there are any App_Browsers/*.browser files.  If there
 430                                         // are we will be using *.browser files for sniffing in addition to browscap.ini
 431                                         string app_browsers_path = Path.Combine (physical_app_path, "App_Browsers");
 432                                         app_browsers_files = new string[0];
 433                                         if (Directory.Exists (app_browsers_path)) {
 434                                                 app_browsers_files = Directory.GetFiles (app_browsers_path, "*.browser");
 435                                         }
 436 #endif
 437
 438                                         if (app_file != null) {
 439 #if TARGET_J2EE
 440                                                 app_file = System.Web.Util.UrlUtils.ResolveVirtualPathFromAppAbsolute("~/" + Path.GetFileName(app_file));
 441                                                 app_type = System.Web.J2EE.PageMapper.GetObjectType(context, app_file);
 442 #else
 443 #if NET_2_0
 444                                                 app_type = BuildManager.GetCompiledType ("~/" + Path.GetFileName (app_file));
 445 #else
 446                                                 app_type = ApplicationFileParser.GetCompiledApplicationType (app_file, context);
 447 #endif
 448 #endif
 449                                                 if (app_type == null) {
 450                                                         string msg = String.Format ("Error compiling application file ({0}).", app_file);
 451                                                         throw new ApplicationException (msg);
 452                                                 }
 453                                         } else {
 454                                                 app_type = typeof (System.Web.HttpApplication);
 455                                                 app_state = new HttpApplicationState ();
 456                                         }
 457
 458                                         WatchLocationForRestart("Global.asax");
 459                                         WatchLocationForRestart("global.asax");
 460                                         WatchLocationForRestart("Web.config");
 461                                         WatchLocationForRestart("web.config");
 462                                         WatchLocationForRestart("Web.Config");
 463                                         needs_init = false;
 464 #if NET_2_0
 465                                 } catch (Exception) {
 466                                         if (BuildManager.CodeAssemblies != null)
 467                                                 BuildManager.CodeAssemblies.Clear ();
 468                                         if (BuildManager.TopLevelAssemblies != null)
 469                                                 BuildManager.TopLevelAssemblies.Clear ();
 470                                         if (WebConfigurationManager.ExtraAssemblies != null)
 471                                                 WebConfigurationManager.ExtraAssemblies.Clear ();
 472                                         throw;
 473                                 }
 474 #endif
 475
 476                                 //
 477                                 // Now init the settings
 478                                 //
 479
 480                         }
 481                 }
 482
 483                 //
 484                 // Multiple-threads might hit this one on startup, and we have
 485                 // to delay-initialize until we have the HttpContext
 486                 //
 487                 internal static HttpApplication GetApplication (HttpContext context)
 488                 {
 489 #if TARGET_J2EE
 490                         if (context.ApplicationInstance!=null)
 491                                 return context.ApplicationInstance;
 492 #endif
 493                         HttpApplicationFactory factory = theFactory;
 494                         HttpApplication app = null;
 495                         if (factory.app_start_needed){
 496                                 if (context == null)
 497                                         return null;
 498
 499                                 factory.InitType (context);
 500                                 lock (factory) {
 501                                         if (factory.app_start_needed) {
 502                                                 foreach (string dir in HttpApplication.BinDirs)
 503                                                         WatchLocationForRestart (dir, "*.dll");
 504 #if NET_2_0
 505                                                                         // Restart if the App_* directories are created...
 506                                                 WatchLocationForRestart (".", "App_Code");
 507                                                 WatchLocationForRestart (".", "App_Browsers");
 508                                                 WatchLocationForRestart (".", "App_GlobalResources");
 509                                                 // ...or their contents is changed.
 510                                                 WatchLocationForRestart ("App_Code", "*", true);
 511                                                 WatchLocationForRestart ("App_Browsers", "*");
 512                                                 WatchLocationForRestart ("App_GlobalResources", "*");
 513 #endif
 514                                                 app = factory.FireOnAppStart (context);
 515                                                 factory.app_start_needed = false;
 516                                                 return app;
 517                                         }
 518                                 }
 519                         }
 520
 521                         lock (factory.available) {
 522                                 if (factory.available.Count > 0) {
 523                                         app = (HttpApplication) factory.available.Pop ();
 524                                         app.RequestCompleted = false;
 525                                         return app;
 526                                 }
 527                         }
 528
 529                         return (HttpApplication) Activator.CreateInstance (factory.app_type, true);
 530                 }
 531
 532                 // The lock is in InvokeSessionEnd
 533                 static HttpApplication GetApplicationForSessionEnd ()
 534                 {
 535                         HttpApplicationFactory factory = theFactory;
 536                         if (factory.available_for_end.Count > 0)
 537                                 return (HttpApplication) factory.available_for_end.Pop ();
 538
 539                         HttpApplication app = (HttpApplication) Activator.CreateInstance (factory.app_type, true);
 540                         app.InitOnce (false);
 541
 542                         return app;
 543                 }
 544
 545                 internal static void RecycleForSessionEnd (HttpApplication app)
 546                 {
 547                         HttpApplicationFactory factory = theFactory;
 548                         lock (factory.available_for_end) {
 549                                 if (factory.available_for_end.Count < 32)
 550                                         factory.available_for_end.Push (app);
 551                                 else
 552                                         app.Dispose ();
 553                         }
 554                 }
 555
 556                 internal static void Recycle (HttpApplication app)
 557                 {
 558                         HttpApplicationFactory factory = theFactory;
 559                         lock (factory.available) {
 560                                 if (factory.available.Count < 32)
 561                                         factory.available.Push (app);
 562                                 else
 563                                         app.Dispose ();
 564                         }
 565                 }
 566
 567                 internal static bool ContextAvailable {
 568                         get { return theFactory != null && !theFactory.app_start_needed; }
 569                 }
 570
 571
 572                 internal static bool WatchLocationForRestart (string filter)
 573                 {
 574                         return WatchLocationForRestart ("", filter, false);
 575                 }
 576
 577                 internal static bool WatchLocationForRestart (string virtualPath, string filter)
 578                 {
 579                         return WatchLocationForRestart (virtualPath, filter, false);
 580                 }
 581
 582                 internal static bool WatchLocationForRestart(string virtualPath, string filter, bool watchSubdirs)
 583                 {
 584                         // map the path to the physical one
 585                         string physicalPath = HttpRuntime.AppDomainAppPath;
 586                         physicalPath = Path.Combine(physicalPath, virtualPath);
 587                         bool isDir = Directory.Exists(physicalPath);
 588                         bool isFile = isDir ? false : File.Exists(physicalPath);
 589
 590                         if (isDir || isFile) {
 591                                 // create the watcher
 592                                 FileSystemEventHandler fseh = new FileSystemEventHandler(OnFileChanged);
 593                                 RenamedEventHandler reh = new RenamedEventHandler(OnFileRenamed);
 594                                 FileSystemWatcher watcher = CreateWatcher(Path.Combine(physicalPath, filter), fseh, reh);
 595                                 if (isDir)
 596                                         watcher.IncludeSubdirectories = watchSubdirs;
 597
 598                                 lock (watchers_lock) {
 599                                         watchers.Add(watcher);
 600                                 }
 601                                 return true;
 602                         } else {
 603                                 return false;
 604                         }
 605                 }
 606
 607 #if NET_2_0
 608                 internal static bool ApplicationDisabled {
 609                         get { return app_disabled; }
 610                         set { app_disabled = value; }
 611                 }
 612
 613                 internal static string[] AppBrowsersFiles {
 614                         get { return app_browsers_files; }
 615                 }
 616
 617                 static System.Web.Configuration.nBrowser.Build capabilities_processor = null;
 618                 static object capabilities_processor_lock = new object();
 619                 internal static System.Web.Configuration.ICapabilitiesProcess CapabilitiesProcessor {
 620                         get {
 621                                 lock (capabilities_processor_lock) {
 622                                         if (capabilities_processor == null) {
 623                                                 capabilities_processor = new System.Web.Configuration.nBrowser.Build();
 624                                                 string machine_browsers_path = Path.Combine (HttpRuntime.MachineConfigurationDirectory, "Browsers");
 625                                                 if (Directory.Exists (machine_browsers_path)) {
 626                                                         string[] machine_browsers_files
 627                                                                 = Directory.GetFiles (machine_browsers_path, "*.browser");
 628                                                         foreach (string f in machine_browsers_files) {
 629                                                                 capabilities_processor.AddBrowserFile(f);
 630                                                         }
 631                                                 }
 632                                                 foreach (string f in app_browsers_files) {
 633                                                         capabilities_processor.AddBrowserFile(f);
 634                                                 }
 635                                         }
 636                                 }
 637                                 return capabilities_processor;
 638                         }
 639                 }
 640 #endif
 641
 642                 internal static void DisableWatchers ()
 643                 {
 644                         lock (watchers_lock) {
 645                                 foreach (FileSystemWatcher watcher in watchers)
 646                                         watcher.EnableRaisingEvents = false;
 647                         }
 648                 }
 649
 650                 internal static void EnableWatchers ()
 651                 {
 652                         lock (watchers_lock) {
 653                                 foreach (FileSystemWatcher watcher in watchers)
 654                                         watcher.EnableRaisingEvents = true;
 655                         }
 656                 }
 657
 658                 static void OnFileRenamed(object sender, RenamedEventArgs args)
 659                 {
 660                         OnFileChanged(sender, args);
 661                 }
 662
 663                 static void OnFileChanged(object sender, FileSystemEventArgs args)
 664                 {
 665                         lock (watchers_lock) {
 666                                 if(app_shutdown)
 667                                         return;
 668                                 app_shutdown = true;
 669
 670                                 // Disable event raising to avoid concurrent restarts
 671                                 DisableWatchers ();
 672
 673                                 // Restart application
 674                                 HttpRuntime.UnloadAppDomain();
 675                         }
 676                 }
 677         }
 678 }
 679