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.Text;
  34 using System.Threading;
  35 using System.Web.Configuration;
  36
  37 namespace System.Web
  38 {
  39         class QueueManager
  40         {
  41                 // keep the defaults in sync with the ones in HttpRuntimeSection.cs
  42                 int minFree = 8;
  43                 int minLocalFree = 4;
  44                 int queueLimit = 5000;
  45                 Queue queue;
  46                 bool disposing;
  47                 Exception initialException;
  48
  49                 public QueueManager ()
  50                 {
  51                         Exception ex = null;
  52
  53                         try {
  54 #if NET_2_0
  55                                 HttpRuntimeSection config;
  56
  57                                 config = (HttpRuntimeSection) WebConfigurationManager.GetSection ("system.web/httpRuntime");
  58 #else
  59                                 HttpRuntimeConfig config;
  60
  61                                 config = (HttpRuntimeConfig) HttpContext.GetAppConfig ("system.web/httpRuntime");
  62 #endif
  63                                 minFree = config.MinFreeThreads;
  64                                 minLocalFree = config.MinLocalRequestFreeThreads;
  65                                 queueLimit = config.AppRequestQueueLimit;
  66                         } catch (Exception e) {
  67                                 ex = e;
  68                         }
  69
  70                         try {
  71                                 queue = new Queue (queueLimit);
  72                         } catch (Exception e) {
  73                                 if (ex == null) {
  74                                         initialException = e;
  75                                 } else {
  76                                         StringBuilder sb = new StringBuilder ("Several exceptions occurred:\n");
  77                                         sb.AppendFormat ("--- Exception Q1:\n{0}\n", ex.ToString ());
  78                                         sb.AppendFormat ("--- Exception Q2:\n{0}\n", e.ToString ());
  79                                         initialException = new Exception (sb.ToString ());
  80                                 }
  81                         }
  82
  83                         if (initialException == null && ex != null)
  84                                 initialException = ex;
  85                 }
  86
  87                 public bool HasException {
  88                         get { return initialException != null; }
  89                 }
  90
  91                 public Exception InitialException {
  92                         get { return initialException; }
  93                 }
  94
  95                 bool CanExecuteRequest (HttpWorkerRequest req)
  96                 {
  97                         if (disposing)
  98                                 return false;
  99
 100 #if TARGET_J2EE
 101                         return true; // The J2EE app server manages the thread pool
 102 #else
 103                         int threads, cports;
 104                         ThreadPool.GetAvailableThreads (out threads, out cports);
 105                         bool local = (req != null && req.GetLocalAddress () == "127.0.0.1");
 106                         return (threads > minFree) || (local && threads > minLocalFree);
 107 #endif
 108                 }
 109
 110                 public HttpWorkerRequest GetNextRequest (HttpWorkerRequest req)
 111                 {
 112                         if (!CanExecuteRequest (req)) {
 113                                 if (!disposing && req != null) {
 114                                         lock (queue) {
 115                                                 Queue (req);
 116                                         }
 117                                 }
 118
 119                                 return null;
 120                         }
 121
 122                         HttpWorkerRequest result;
 123                         lock (queue) {
 124                                 result = Dequeue ();
 125                                 if (result != null) {
 126                                         if (req != null)
 127                                                 Queue (req);
 128                                 } else {
 129                                         result = req;
 130                                 }
 131                         }
 132
 133                         return result;
 134                 }
 135
 136                 void Queue (HttpWorkerRequest wr)
 137                 {
 138                         if (queue.Count < queueLimit) {
 139                                 queue.Enqueue (wr);
 140                                 return;
 141                         }
 142
 143                         HttpRuntime.FinishUnavailable (wr);
 144                 }
 145
 146                 HttpWorkerRequest Dequeue ()
 147                 {
 148                         if (queue.Count > 0)
 149                                 return (HttpWorkerRequest) queue.Dequeue ();
 150
 151                         return null;
 152                 }
 153
 154                 public void Dispose ()
 155                 {
 156                         if (disposing)
 157                                 return;
 158
 159                         disposing = true;
 160                         HttpWorkerRequest wr;
 161                         while ((wr = GetNextRequest (null)) != null)
 162                                 HttpRuntime.FinishUnavailable (wr);
 163
 164                         queue = null;
 165                 }
 166         }
 167 }
 168