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                 DateTime start;
  58                 bool changed;
  59                 bool disposed;
  60                 CacheEntry [] entries;
  61                 CacheItemRemovedCallback removedDelegate;
  62                 FileSystemWatcher [] watchers;
  63
  64                 private CacheDependency ()
  65                 {
  66                 }
  67
  68                 public CacheDependency (string filename)
  69                         : this (filename, DateTime.MaxValue)
  70                 {
  71                 }
  72
  73                 public CacheDependency (string filename, DateTime start)
  74                         : this (new string [] {filename}, null, null, start)
  75                 {
  76                 }
  77
  78                 public CacheDependency (string [] filenames)
  79                         : this (filenames, null, null, DateTime.MaxValue)
  80                 {
  81                 }
  82
  83                 public CacheDependency (string [] filenames, DateTime start)
  84                         : this (filenames, null, null, start)
  85                 {
  86                 }
  87
  88                 public CacheDependency (string [] filenames, string [] cachekeys)
  89                         : this (filenames, cachekeys, null, DateTime.MaxValue)
  90                 {
  91                 }
  92
  93                 public CacheDependency (string [] filenames, string [] cachekeys, DateTime start)
  94                         : this (filenames, cachekeys, null, start)
  95                 {
  96                 }
  97
  98                 public CacheDependency (string [] filenames, string [] cachekeys, CacheDependency dependency)
  99                         : this (filenames, cachekeys, dependency, DateTime.MaxValue)
 100                 {
 101                 }
 102
 103                 public CacheDependency (string [] filenames,
 104                                         string [] cachekeys,
 105                                         CacheDependency dependency,
 106                                         DateTime start)
 107                 {
 108                         Cache cache = HttpRuntime.Cache;
 109
 110                         this.start = start;
 111                         if (filenames == null)
 112                                 filenames = noStrings;
 113
 114                         foreach (string file in filenames) {
 115                                 if (file == null)
 116                                         throw new ArgumentNullException ("filenames");
 117                         }
 118
 119                         if (cachekeys == null)
 120                                 cachekeys = noStrings;
 121
 122                         int missing_keys = 0;
 123                         foreach (string ck in cachekeys) {
 124                                 if (ck == null)
 125                                         throw new ArgumentNullException ("cachekeys");
 126                                 if (cache.GetEntry (ck) == null)
 127                                         missing_keys++;
 128                         }
 129
 130                         if (dependency == null)
 131                                 dependency = noDependency;
 132
 133
 134                         this.changed = dependency.changed;
 135                         if (changed == true)
 136                                 return;
 137
 138                         int nentries = cachekeys.Length + ((dependency.entries == null) ? 0 :
 139                                                                   dependency.entries.Length) - missing_keys;
 140
 141                         if (nentries != 0) {
 142                                 this.removedDelegate = new CacheItemRemovedCallback (CacheItemRemoved);
 143                                 this.entries = new CacheEntry [nentries];
 144
 145                                 int i = 0;
 146                                 if (dependency.entries != null) {
 147                                         foreach (CacheEntry entry in dependency.entries) {
 148                                                 entry._onRemoved += removedDelegate;
 149                                                 entries [i++] = entry;
 150                                         }
 151                                 }
 152
 153                                 for (int c=0; c<cachekeys.Length; c++) {
 154                                         CacheEntry entry = cache.GetEntry (cachekeys [c]);
 155                                         if (entry == null)
 156                                                 continue;
 157                                         entry._onRemoved += removedDelegate;
 158                                         entries [i++] = entry;
 159                                 }
 160                         }
 161
 162                         if (filenames.Length > 0) {
 163                                 watchers = new FileSystemWatcher [filenames.Length];
 164                                 for (int i=0; i<filenames.Length; i++)
 165                                         watchers [i] = CreateWatcher (filenames [i]);
 166                         }
 167                 }
 168
 169                 private FileSystemWatcher CreateWatcher (string file)
 170                 {
 171                         FileSystemWatcher watcher = new FileSystemWatcher ();
 172
 173                         watcher.Path = Path.GetFullPath (Path.GetDirectoryName (file));
 174                         watcher.Filter = Path.GetFileName (file);
 175
 176                         watcher.Changed += new FileSystemEventHandler (OnFileChanged);
 177                         watcher.Created += new FileSystemEventHandler (OnFileChanged);
 178                         watcher.Deleted += new FileSystemEventHandler (OnFileChanged);
 179
 180                         watcher.EnableRaisingEvents = true;
 181
 182                         return watcher;
 183                 }
 184
 185                 private void OnFileChanged (object sender, FileSystemEventArgs e)
 186                 {
 187                         OnChanged (sender, e);
 188                 }
 189
 190                 void CacheItemRemoved (string key, object value, CacheItemRemovedReason reason)
 191                 {
 192                         OnChanged (this, EventArgs.Empty);
 193                 }
 194
 195                 void OnChanged (object sender, EventArgs args)
 196                 {
 197                         if (changed || disposed)
 198                                 return;
 199
 200                         changed = true;
 201                         if (Changed != null)
 202                                 Changed (this, new CacheDependencyChangedArgs (null));
 203                 }
 204
 205                 public void Dispose ()
 206                 {
 207                         for (int i=0; i<watchers.Length; i++)
 208                                 watchers [i].Dispose ();
 209                 }
 210
 211                 public bool HasChanged
 212                 {
 213                         get { return changed; }
 214                 }
 215
 216                 internal CacheEntry [] GetCacheEntries ()
 217                 {
 218                         return entries;
 219                 }
 220
 221                 internal event CacheDependencyChangedHandler Changed;
 222         }
 223 }
 224