mcs/class/System.Web/System.Web.Caching/CacheDependency.cs

   1 //
   2 // System.Web.Caching.CachedDependency
   3 //
   4 // Author(s):
   5 //  Lluis Sanchez (lluis@ximian.com)
   6 //
   7 // (C) 2005 Novell, Inc (http://www.novell.com)
   8 //
   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
  30 using System.Collections;
  31 using System.IO;
  32 using System.Security.Permissions;
  33
  34 namespace System.Web.Caching
  35 {
  36 #if NET_2_0
  37         // CAS
  38         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  39         [AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  40         public class CacheDependency: IDisposable {
  41 #else
  42         // CAS - no InheritanceDemand here as the class is sealed
  43         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  44         public sealed class CacheDependency: IDisposable {
  45 #endif
  46                 string[] cachekeys;
  47                 CacheDependency dependency;
  48                 DateTime start;
  49                 Cache cache;
  50 #if !TARGET_JVM
  51                 FileSystemWatcher[] watchers;
  52 #endif
  53                 bool hasChanged;
  54                 object locker = new object ();
  55
  56                 public CacheDependency (string filename): this (new string[] { filename }, null, null, DateTime.Now)
  57                 {
  58                 }
  59
  60                 public CacheDependency (string[] filenames): this (filenames, null, null, DateTime.Now)
  61                 {
  62                 }
  63
  64                 public CacheDependency (string filename, DateTime start): this (new string[] { filename }, null, null, start)
  65                 {
  66                 }
  67
  68                 public CacheDependency (string [] filenames, DateTime start)
  69                         : this (filenames, null, null, start)
  70                 {
  71                 }
  72
  73                 public CacheDependency (string[] filenames, string[] cachekeys): this (filenames, cachekeys, null, DateTime.Now)
  74                 {
  75                 }
  76
  77                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency): this (filenames, cachekeys, dependency, DateTime.Now)
  78                 {
  79                 }
  80
  81                 public CacheDependency (string[] filenames, string[] cachekeys, DateTime start): this (filenames, cachekeys, null, start)
  82                 {
  83                 }
  84
  85                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency, DateTime start)
  86                 {
  87 #if !TARGET_JVM
  88                         if (filenames != null) {
  89                                 watchers = new FileSystemWatcher [filenames.Length];
  90                                 for (int n=0; n<filenames.Length; n++) {
  91                                         FileSystemWatcher watcher = new FileSystemWatcher ();
  92                                         if (Directory.Exists (filenames [n])) {
  93                                                 watcher.Path = filenames [n];
  94                                         } else {
  95                                                 string parentPath = Path.GetDirectoryName (filenames [n]);
  96                                                 if (parentPath != null && Directory.Exists (parentPath)) {
  97                                                         watcher.Path = parentPath;
  98                                                         watcher.Filter = Path.GetFileName (filenames [n]);
  99                                                 } else
 100                                                         continue;
 101                                         }
 102                                         watcher.Created += new FileSystemEventHandler (OnChanged);
 103                                         watcher.Changed += new FileSystemEventHandler (OnChanged);
 104                                         watcher.Deleted += new FileSystemEventHandler (OnChanged);
 105                                         watcher.Renamed += new RenamedEventHandler (OnChanged);
 106                                         watcher.EnableRaisingEvents = true;
 107                                         watchers [n] = watcher;
 108                                 }
 109                         }
 110 #endif
 111                         this.cachekeys = cachekeys;
 112                         this.dependency = dependency;
 113                         if (dependency != null)
 114                                 dependency.DependencyChanged += new EventHandler (OnChildDependencyChanged);
 115                         this.start = start;
 116                 }
 117 #if !TARGET_JVM
 118                 void OnChanged (object sender, FileSystemEventArgs args)
 119                 {
 120                         if (DateTime.Now < start)
 121                                 return;
 122                         hasChanged = true;
 123                         DisposeWatchers ();
 124
 125                         if (cache != null)
 126                                 cache.CheckExpiration ();
 127                 }
 128
 129                 void DisposeWatchers ()
 130                 {
 131                         lock (locker) {
 132                                 if (watchers != null) {
 133                                         foreach (FileSystemWatcher w in watchers)
 134                                                 if (w != null)
 135                                                         w.Dispose ();
 136                                 }
 137                                 watchers = null;
 138                         }
 139                 }
 140 #else
 141                 void DisposeWatchers ()
 142                 {
 143                 }
 144 #endif
 145                 public void Dispose ()
 146                 {
 147                         DisposeWatchers ();
 148                         if (dependency != null)
 149                                 dependency.DependencyChanged -= new EventHandler (OnChildDependencyChanged);
 150                         cache = null;
 151                 }
 152
 153                 internal void SetCache (Cache c)
 154                 {
 155                         cache = c;
 156                 }
 157
 158                 public bool HasChanged {
 159                         get {
 160                                 if (hasChanged)
 161                                         return true;
 162
 163                                 if (DateTime.Now < start)
 164                                         return false;
 165
 166                                 if (cache != null && cachekeys != null) {
 167                                         foreach (string key in cachekeys) {
 168                                                 if (cache.GetKeyLastChange (key) > start) {
 169                                                         hasChanged = true;
 170                                                         break;
 171                                                 }
 172                                         }
 173                                 }
 174                                 if (hasChanged)
 175                                         DisposeWatchers ();
 176
 177                                 return hasChanged;
 178                         }
 179                 }
 180
 181                 void OnChildDependencyChanged (object o, EventArgs a)
 182                 {
 183                         hasChanged = true;
 184                         OnDependencyChanged ();
 185                 }
 186
 187                 void OnDependencyChanged ()
 188                 {
 189                         if (DependencyChanged != null)
 190                                 DependencyChanged (this, null);
 191                 }
 192
 193                 internal event EventHandler DependencyChanged;
 194         }
 195 }