mcs/class/System.Web/System.Web/QueueManager.cs

   1 //
   2 // System.Web.QueueManager
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //
   7 // (C) 2003,2004 Novell, Inc (http://www.novell.com)
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using System.Collections;
  33 using System.Diagnostics;
  34 using System.Text;
  35 using System.Threading;
  36 using System.Web.Configuration;
  37
  38 namespace System.Web
  39 {
  40         class QueueManager
  41         {
  42                 // keep the defaults in sync with the ones in HttpRuntimeSection.cs
  43                 int minFree = 8;
  44                 int minLocalFree = 4;
  45                 int queueLimit = 5000;
  46                 Queue queue;
  47                 bool disposing;
  48                 Exception initialException;
  49                 PerformanceCounter requestsQueuedCounter;
  50
  51                 public QueueManager ()
  52                 {
  53                         Exception ex = null;
  54
  55                         try {
  56 #if NET_2_0
  57                                 HttpRuntimeSection config;
  58
  59                                 config = (HttpRuntimeSection) WebConfigurationManager.GetWebApplicationSection ("system.web/httpRuntime");
  60 #else
  61                                 HttpRuntimeConfig config;
  62
  63                                 config = (HttpRuntimeConfig) HttpContext.GetAppConfig ("system.web/httpRuntime");
  64 #endif
  65                                 minFree = config.MinFreeThreads;
  66                                 minLocalFree = config.MinLocalRequestFreeThreads;
  67                                 queueLimit = config.AppRequestQueueLimit;
  68                         } catch (Exception e) {
  69                                 ex = e;
  70                         }
  71
  72                         try {
  73                                 queue = new Queue (queueLimit);
  74                         } catch (Exception e) {
  75                                 if (ex == null) {
  76                                         initialException = e;
  77                                 } else {
  78                                         StringBuilder sb = new StringBuilder ("Several exceptions occurred:\n");
  79                                         sb.AppendFormat ("--- Exception Q1:\n{0}\n", ex.ToString ());
  80                                         sb.AppendFormat ("--- Exception Q2:\n{0}\n", e.ToString ());
  81                                         initialException = new Exception (sb.ToString ());
  82                                 }
  83                         }
  84
  85                         if (initialException == null && ex != null)
  86                                 initialException = ex;
  87
  88                         requestsQueuedCounter = new PerformanceCounter ("ASP.NET", "Requests Queued");
  89                         requestsQueuedCounter.RawValue = 0;
  90                 }
  91
  92                 public bool HasException {
  93                         get { return initialException != null; }
  94                 }
  95
  96                 public Exception InitialException {
  97                         get { return initialException; }
  98                 }
  99
 100                 bool CanExecuteRequest (HttpWorkerRequest req)
 101                 {
 102                         if (disposing)
 103                                 return false;
 104
 105 #if TARGET_J2EE
 106                         return true; // The J2EE app server manages the thread pool
 107 #else
 108                         int threads, cports;
 109                         ThreadPool.GetAvailableThreads (out threads, out cports);
 110                         bool local = (req != null && req.GetLocalAddress () == "127.0.0.1");
 111                         return (threads > minFree) || (local && threads > minLocalFree);
 112 #endif
 113                 }
 114
 115                 public HttpWorkerRequest GetNextRequest (HttpWorkerRequest req)
 116                 {
 117                         if (!CanExecuteRequest (req)) {
 118                                 if (!disposing && req != null) {
 119                                         lock (queue) {
 120                                                 Queue (req);
 121                                         }
 122                                 }
 123
 124                                 return null;
 125                         }
 126
 127                         HttpWorkerRequest result;
 128                         lock (queue) {
 129                                 result = Dequeue ();
 130                                 if (result != null) {
 131                                         if (req != null)
 132                                                 Queue (req);
 133                                 } else {
 134                                         result = req;
 135                                 }
 136                         }
 137
 138                         return result;
 139                 }
 140
 141                 void Queue (HttpWorkerRequest wr)
 142                 {
 143                         if (queue.Count < queueLimit) {
 144                                 queue.Enqueue (wr);
 145                                 requestsQueuedCounter.Increment ();
 146                                 return;
 147                         }
 148
 149                         HttpRuntime.FinishUnavailable (wr);
 150                 }
 151
 152                 HttpWorkerRequest Dequeue ()
 153                 {
 154                         if (queue.Count > 0) {
 155                                 HttpWorkerRequest request = (HttpWorkerRequest) queue.Dequeue ();
 156                                 requestsQueuedCounter.Decrement ();
 157                                 return request;
 158                         }
 159
 160                         return null;
 161                 }
 162
 163                 public void Dispose ()
 164                 {
 165                         if (disposing)
 166                                 return;
 167
 168                         disposing = true;
 169                         HttpWorkerRequest wr;
 170                         while ((wr = GetNextRequest (null)) != null)
 171                                 HttpRuntime.FinishUnavailable (wr);
 172
 173                         queue = null;
 174                 }
 175         }
 176 }
 177