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 #if NET_2_0
  34 using System.Text;
  35 #endif
  36
  37 namespace System.Web.Caching
  38 {
  39 #if NET_2_0
  40         // CAS
  41         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  42         [AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  43         public class CacheDependency: IDisposable {
  44 #else
  45         // CAS - no InheritanceDemand here as the class is sealed
  46         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  47         public sealed class CacheDependency: IDisposable {
  48 #endif
  49                 string[] cachekeys;
  50                 CacheDependency dependency;
  51                 DateTime start;
  52                 Cache cache;
  53                 FileSystemWatcher[] watchers;
  54                 bool hasChanged;
  55 #if NET_2_0
  56                 bool used;
  57 #endif
  58                 object locker = new object ();
  59
  60 #if NET_2_0
  61                 public CacheDependency (): this (null, null, null, DateTime.Now)
  62                 {
  63                 }
  64 #endif
  65
  66                 public CacheDependency (string filename): this (new string[] { filename }, null, null, DateTime.Now)
  67                 {
  68                 }
  69
  70                 public CacheDependency (string[] filenames): this (filenames, null, null, DateTime.Now)
  71                 {
  72                 }
  73
  74                 public CacheDependency (string filename, DateTime start): this (new string[] { filename }, null, null, start)
  75                 {
  76                 }
  77
  78                 public CacheDependency (string [] filenames, DateTime start)
  79                         : this (filenames, null, null, start)
  80                 {
  81                 }
  82
  83                 public CacheDependency (string[] filenames, string[] cachekeys): this (filenames, cachekeys, null, DateTime.Now)
  84                 {
  85                 }
  86
  87                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency): this (filenames, cachekeys, dependency, DateTime.Now)
  88                 {
  89                 }
  90
  91                 public CacheDependency (string[] filenames, string[] cachekeys, DateTime start): this (filenames, cachekeys, null, start)
  92                 {
  93                 }
  94
  95                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency, DateTime start)
  96                 {
  97                         if (filenames != null) {
  98                                 watchers = new FileSystemWatcher [filenames.Length];
  99                                 for (int n=0; n<filenames.Length; n++) {
 100                                         FileSystemWatcher watcher = new FileSystemWatcher ();
 101                                         if (Directory.Exists (filenames [n])) {
 102                                                 watcher.Path = filenames [n];
 103                                         } else {
 104                                                 string parentPath = Path.GetDirectoryName (filenames [n]);
 105                                                 if (parentPath != null && Directory.Exists (parentPath)) {
 106                                                         watcher.Path = parentPath;
 107                                                         watcher.Filter = Path.GetFileName (filenames [n]);
 108                                                 } else
 109                                                         continue;
 110                                         }
 111                                         watcher.Created += new FileSystemEventHandler (OnChanged);
 112                                         watcher.Changed += new FileSystemEventHandler (OnChanged);
 113                                         watcher.Deleted += new FileSystemEventHandler (OnChanged);
 114                                         watcher.Renamed += new RenamedEventHandler (OnChanged);
 115                                         watcher.EnableRaisingEvents = true;
 116                                         watchers [n] = watcher;
 117                                 }
 118                         }
 119                         this.cachekeys = cachekeys;
 120                         this.dependency = dependency;
 121                         if (dependency != null)
 122                                 dependency.DependencyChanged += new EventHandler (OnChildDependencyChanged);
 123                         this.start = start;
 124                 }
 125
 126 #if NET_2_0
 127                 public virtual string GetUniqueID ()
 128                 {
 129                         StringBuilder sb = new StringBuilder ();
 130                         lock (locker) {
 131                                 if (watchers != null)
 132                                         foreach (FileSystemWatcher fsw in watchers)
 133                                                 if (fsw != null && fsw.Path != null && fsw.Path.Length != 0)
 134                                                         sb.AppendFormat ("_{0}", fsw.Path);
 135                         }
 136
 137                         if (cachekeys != null)
 138                                 foreach (string key in cachekeys)
 139                                         sb.AppendFormat ("_{0}", key);
 140                         return sb.ToString ();
 141                 }
 142 #endif
 143
 144                 void OnChanged (object sender, FileSystemEventArgs args)
 145                 {
 146                         if (DateTime.Now < start)
 147                                 return;
 148                         hasChanged = true;
 149                         DisposeWatchers ();
 150
 151                         if (cache != null)
 152                                 cache.CheckExpiration ();
 153                 }
 154
 155                 void DisposeWatchers ()
 156                 {
 157                         lock (locker) {
 158                                 if (watchers != null) {
 159                                         foreach (FileSystemWatcher w in watchers)
 160                                                 if (w != null)
 161                                                         w.Dispose ();
 162                                 }
 163                                 watchers = null;
 164                         }
 165                 }
 166                 public void Dispose ()
 167                 {
 168                         DisposeWatchers ();
 169                         if (dependency != null)
 170                                 dependency.DependencyChanged -= new EventHandler (OnChildDependencyChanged);
 171                         cache = null;
 172                 }
 173
 174                 internal void SetCache (Cache c)
 175                 {
 176                         cache = c;
 177 #if NET_2_0
 178                         used = c != null;
 179 #endif
 180                 }
 181
 182 #if NET_2_0
 183                 internal bool IsUsed {
 184                         get { return used; }
 185                 }
 186
 187                 internal DateTime Start {
 188                         get { return start; }
 189                         set { start = value; }
 190                 }
 191 #endif
 192
 193                 public bool HasChanged {
 194                         get {
 195                                 if (hasChanged)
 196                                         return true;
 197
 198                                 if (DateTime.Now < start)
 199                                         return false;
 200
 201                                 if (cache != null && cachekeys != null) {
 202                                         foreach (string key in cachekeys) {
 203                                                 if (cache.GetKeyLastChange (key) > start) {
 204                                                         hasChanged = true;
 205                                                         break;
 206                                                 }
 207                                         }
 208                                 }
 209                                 if (hasChanged)
 210                                         DisposeWatchers ();
 211
 212                                 return hasChanged;
 213                         }
 214                 }
 215
 216                 void OnChildDependencyChanged (object o, EventArgs a)
 217                 {
 218                         hasChanged = true;
 219                         OnDependencyChanged ();
 220                 }
 221
 222                 void OnDependencyChanged ()
 223                 {
 224                         if (DependencyChanged != null)
 225                                 DependencyChanged (this, null);
 226                 }
 227
 228 #if NET_2_0
 229                 internal void SignalDependencyChanged ()
 230                 {
 231                         OnDependencyChanged ();
 232                 }
 233 #endif
 234                 internal event EventHandler DependencyChanged;
 235         }
 236 }