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

   1 //
   2 // System.Web.Caching.CacheDependency
   3 //
   4 // Authors:
   5 //      Patrik Torstensson
   6 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   7 //
   8 // (c) 2003 Ximian, Inc. (http://www.ximian.com)
   9 //
  10
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31 using System;
  32 using System.IO;
  33 using System.Web;
  34
  35 namespace System.Web.Caching
  36 {
  37         internal class CacheDependencyChangedArgs : EventArgs
  38         {
  39                 string key;
  40
  41                 public CacheDependencyChangedArgs (string key)
  42                 {
  43                         this.key = key;
  44                 }
  45
  46                 public string Key {
  47                         get { return key; }
  48                 }
  49         }
  50
  51         internal delegate void CacheDependencyChangedHandler (object sender, CacheDependencyChangedArgs args);
  52
  53         public sealed class CacheDependency : IDisposable
  54         {
  55                 static string [] noStrings = new string [0];
  56                 static CacheDependency noDependency = new CacheDependency ();
  57                 bool changed;
  58                 bool disposed;
  59                 CacheEntry [] entries;
  60                 CacheItemRemovedCallback removedDelegate;
  61                 FileSystemWatcher [] watchers;
  62
  63                 private CacheDependency ()
  64                 {
  65                 }
  66
  67                 public CacheDependency (string filename)
  68                         : this (filename, DateTime.MaxValue)
  69                 {
  70                 }
  71
  72                 public CacheDependency (string filename, DateTime start)
  73                         : this (new string [] {filename}, null, null, start)
  74                 {
  75                 }
  76
  77                 public CacheDependency (string [] filenames)
  78                         : this (filenames, null, null, DateTime.MaxValue)
  79                 {
  80                 }
  81
  82                 public CacheDependency (string [] filenames, DateTime start)
  83                         : this (filenames, null, null, start)
  84                 {
  85                 }
  86
  87                 public CacheDependency (string [] filenames, string [] cachekeys)
  88                         : this (filenames, cachekeys, null, DateTime.MaxValue)
  89                 {
  90                 }
  91
  92                 public CacheDependency (string [] filenames, string [] cachekeys, DateTime start)
  93                         : this (filenames, cachekeys, null, start)
  94                 {
  95                 }
  96
  97                 public CacheDependency (string [] filenames, string [] cachekeys, CacheDependency dependency)
  98                         : this (filenames, cachekeys, dependency, DateTime.MaxValue)
  99                 {
 100                 }
 101
 102                 public CacheDependency (string [] filenames,
 103                                         string [] cachekeys,
 104                                         CacheDependency dependency,
 105                                         DateTime start)
 106                 {
 107                         Cache cache = HttpRuntime.Cache;
 108
 109                         if (filenames == null)
 110                                 filenames = noStrings;
 111
 112                         foreach (string file in filenames) {
 113                                 if (file == null)
 114                                         throw new ArgumentNullException ("filenames");
 115                         }
 116
 117                         if (cachekeys == null)
 118                                 cachekeys = noStrings;
 119
 120                         int missing_keys = 0;
 121                         foreach (string ck in cachekeys) {
 122                                 if (ck == null)
 123                                         throw new ArgumentNullException ("cachekeys");
 124                                 if (cache.GetEntry (ck) == null)
 125                                         missing_keys++;
 126                         }
 127
 128                         if (dependency == null)
 129                                 dependency = noDependency;
 130
 131
 132                         this.changed = dependency.changed;
 133                         if (changed == true)
 134                                 return;
 135
 136                         int nentries = cachekeys.Length + ((dependency.entries == null) ? 0 :
 137                                                                   dependency.entries.Length) - missing_keys;
 138
 139                         if (nentries != 0) {
 140                                 this.removedDelegate = new CacheItemRemovedCallback (CacheItemRemoved);
 141                                 this.entries = new CacheEntry [nentries];
 142
 143                                 int i = 0;
 144                                 if (dependency.entries != null) {
 145                                         foreach (CacheEntry entry in dependency.entries) {
 146                                                 entry._onRemoved += removedDelegate;
 147                                                 entries [i++] = entry;
 148                                         }
 149                                 }
 150
 151                                 for (int c=0; c<cachekeys.Length; c++) {
 152                                         CacheEntry entry = cache.GetEntry (cachekeys [c]);
 153                                         if (entry == null)
 154                                                 continue;
 155                                         entry._onRemoved += removedDelegate;
 156                                         entries [i++] = entry;
 157                                 }
 158                         }
 159
 160                         if (filenames.Length > 0) {
 161                                 watchers = new FileSystemWatcher [filenames.Length];
 162                                 for (int i=0; i<filenames.Length; i++)
 163                                         watchers [i] = CreateWatcher (filenames [i]);
 164                         }
 165                 }
 166
 167                 private FileSystemWatcher CreateWatcher (string file)
 168                 {
 169                         FileSystemWatcher watcher = new FileSystemWatcher ();
 170
 171                         watcher.Path = Path.GetFullPath (Path.GetDirectoryName (file));
 172                         watcher.Filter = Path.GetFileName (file);
 173
 174                         watcher.Changed += new FileSystemEventHandler (OnFileChanged);
 175                         watcher.Created += new FileSystemEventHandler (OnFileChanged);
 176                         watcher.Deleted += new FileSystemEventHandler (OnFileChanged);
 177
 178                         watcher.EnableRaisingEvents = true;
 179
 180                         return watcher;
 181                 }
 182
 183                 private void OnFileChanged (object sender, FileSystemEventArgs e)
 184                 {
 185                         OnChanged (sender, e);
 186                 }
 187
 188                 void CacheItemRemoved (string key, object value, CacheItemRemovedReason reason)
 189                 {
 190                         OnChanged (this, EventArgs.Empty);
 191                 }
 192
 193                 void OnChanged (object sender, EventArgs args)
 194                 {
 195                         if (changed || disposed)
 196                                 return;
 197
 198                         changed = true;
 199                         if (Changed != null)
 200                                 Changed (this, new CacheDependencyChangedArgs (null));
 201                 }
 202
 203                 public void Dispose ()
 204                 {
 205                         for (int i=0; i<watchers.Length; i++)
 206                                 watchers [i].Dispose ();
 207                 }
 208
 209                 public bool HasChanged
 210                 {
 211                         get { return changed; }
 212                 }
 213
 214                 internal CacheEntry [] GetCacheEntries ()
 215                 {
 216                         return entries;
 217                 }
 218
 219                 internal event CacheDependencyChangedHandler Changed;
 220         }
 221 }
 222