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 using System.Text;
  34
  35 namespace System.Web.Caching
  36 {
  37 #if NET_2_0
  38         // CAS
  39         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  40         [AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  41         public class CacheDependency: IDisposable {
  42 #else
  43         // CAS - no InheritanceDemand here as the class is sealed
  44         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  45         public sealed class CacheDependency: IDisposable {
  46 #endif
  47                 string[] cachekeys;
  48                 CacheDependency dependency;
  49                 DateTime start;
  50                 Cache cache;
  51 #if !TARGET_JVM
  52                 FileSystemWatcher[] watchers;
  53 #endif
  54                 bool hasChanged;
  55                 object locker = new object ();
  56 #if NET_2_0
  57                 string unique_id;
  58
  59                 protected CacheDependency ()
  60                 {
  61                 }
  62 #endif
  63
  64                 public CacheDependency (string filename): this (new string[] { filename }, null, null, DateTime.Now)
  65                 {
  66                 }
  67
  68                 public CacheDependency (string[] filenames): this (filenames, null, null, DateTime.Now)
  69                 {
  70                 }
  71
  72                 public CacheDependency (string filename, DateTime start): this (new string[] { filename }, null, null, start)
  73                 {
  74                 }
  75
  76                 public CacheDependency (string [] filenames, DateTime start)
  77                         : this (filenames, null, null, start)
  78                 {
  79                 }
  80
  81                 public CacheDependency (string[] filenames, string[] cachekeys): this (filenames, cachekeys, null, DateTime.Now)
  82                 {
  83                 }
  84
  85                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency): this (filenames, cachekeys, dependency, DateTime.Now)
  86                 {
  87                 }
  88
  89                 public CacheDependency (string[] filenames, string[] cachekeys, DateTime start): this (filenames, cachekeys, null, start)
  90                 {
  91                 }
  92
  93                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency, DateTime start)
  94                 {
  95 #if NET_2_0
  96                         StringBuilder sb = new StringBuilder ();
  97                         sb.Append ("@UID@");
  98 #endif
  99 #if !TARGET_JVM
 100                         if (filenames != null) {
 101                                 watchers = new FileSystemWatcher [filenames.Length];
 102                                 for (int n=0; n<filenames.Length; n++) {
 103                                         FileSystemWatcher watcher = new FileSystemWatcher ();
 104 #if NET_2_0
 105                                         sb.Append (filenames [n]);
 106 #endif
 107                                         if (Directory.Exists (filenames [n])) {
 108                                                 watcher.Path = filenames [n];
 109                                         } else {
 110                                                 string parentPath = Path.GetDirectoryName (filenames [n]);
 111                                                 if (parentPath != null && Directory.Exists (parentPath)) {
 112                                                         watcher.Path = parentPath;
 113                                                         watcher.Filter = Path.GetFileName (filenames [n]);
 114                                                 } else
 115                                                         continue;
 116                                         }
 117                                         watcher.Created += new FileSystemEventHandler (OnChanged);
 118                                         watcher.Changed += new FileSystemEventHandler (OnChanged);
 119                                         watcher.Deleted += new FileSystemEventHandler (OnChanged);
 120                                         watcher.Renamed += new RenamedEventHandler (OnChanged);
 121                                         watcher.EnableRaisingEvents = true;
 122                                         watchers [n] = watcher;
 123                                 }
 124                         }
 125 #endif
 126                         this.cachekeys = cachekeys;
 127 #if NET_2_0
 128                         if (cachekeys != null) {
 129                                 foreach (string s in cachekeys)
 130                                         sb.Append (s);
 131                         }
 132                         if (sb.Length > 5) // 5 is the length of "@UID@"
 133                                 unique_id = sb.ToString ();
 134 #endif
 135
 136                         this.dependency = dependency;
 137                         if (dependency != null)
 138                                 dependency.DependencyChanged += new EventHandler (OnChildDependencyChanged);
 139                         this.start = start;
 140                 }
 141 #if !TARGET_JVM
 142                 void OnChanged (object sender, FileSystemEventArgs args)
 143                 {
 144                         if (DateTime.Now < start)
 145                                 return;
 146                         hasChanged = true;
 147                         DisposeWatchers ();
 148
 149                         if (cache != null)
 150                                 cache.CheckExpiration ();
 151                 }
 152
 153                 void DisposeWatchers ()
 154                 {
 155                         lock (locker) {
 156                                 if (watchers != null) {
 157                                         foreach (FileSystemWatcher w in watchers)
 158                                                 if (w != null)
 159                                                         w.Dispose ();
 160                                 }
 161                                 watchers = null;
 162                         }
 163                 }
 164 #else
 165                 void DisposeWatchers ()
 166                 {
 167                 }
 168 #endif
 169                 public void Dispose ()
 170                 {
 171                         DisposeWatchers ();
 172                         if (dependency != null)
 173                                 dependency.DependencyChanged -= new EventHandler (OnChildDependencyChanged);
 174                         cache = null;
 175                 }
 176
 177                 internal void SetCache (Cache c)
 178                 {
 179                         cache = c;
 180                 }
 181
 182 #if NET_2_0
 183                 public virtual string GetUniqueID ()
 184                 {
 185                         return unique_id;
 186                 }
 187
 188                 public virtual bool HasChanged {
 189 #else
 190                 public bool HasChanged {
 191 #endif
 192                         get {
 193                                 if (hasChanged)
 194                                         return true;
 195
 196                                 if (DateTime.Now < start)
 197                                         return false;
 198
 199                                 if (cache != null && cachekeys != null) {
 200                                         foreach (string key in cachekeys) {
 201                                                 if (cache.GetKeyLastChange (key) > start) {
 202                                                         hasChanged = true;
 203                                                         break;
 204                                                 }
 205                                         }
 206                                 }
 207                                 if (hasChanged)
 208                                         DisposeWatchers ();
 209
 210                                 return hasChanged;
 211                         }
 212                 }
 213
 214                 void OnChildDependencyChanged (object o, EventArgs a)
 215                 {
 216                         hasChanged = true;
 217                         OnDependencyChanged ();
 218                 }
 219
 220                 internal void OnDependencyChanged ()
 221                 {
 222                         if (DependencyChanged != null)
 223                                 DependencyChanged (this, null);
 224                 }
 225
 226                 internal event EventHandler DependencyChanged;
 227         }
 228 }