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 #if !TARGET_JVM
  54                 FileSystemWatcher[] watchers;
  55 #endif
  56                 bool hasChanged;
  57 #if NET_2_0
  58                 bool used;
  59 #endif
  60                 object locker = new object ();
  61
  62 #if NET_2_0
  63                 public CacheDependency (): this (null, null, null, DateTime.Now)
  64                 {
  65                 }
  66 #endif
  67
  68                 public CacheDependency (string filename): this (new string[] { filename }, null, null, DateTime.Now)
  69                 {
  70                 }
  71
  72                 public CacheDependency (string[] filenames): this (filenames, null, null, DateTime.Now)
  73                 {
  74                 }
  75
  76                 public CacheDependency (string filename, DateTime start): this (new string[] { filename }, null, null, start)
  77                 {
  78                 }
  79
  80                 public CacheDependency (string [] filenames, DateTime start)
  81                         : this (filenames, null, null, start)
  82                 {
  83                 }
  84
  85                 public CacheDependency (string[] filenames, string[] cachekeys): this (filenames, cachekeys, null, DateTime.Now)
  86                 {
  87                 }
  88
  89                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency): this (filenames, cachekeys, dependency, DateTime.Now)
  90                 {
  91                 }
  92
  93                 public CacheDependency (string[] filenames, string[] cachekeys, DateTime start): this (filenames, cachekeys, null, start)
  94                 {
  95                 }
  96
  97                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency, DateTime start)
  98                 {
  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 (Directory.Exists (filenames [n])) {
 105                                                 watcher.Path = filenames [n];
 106                                         } else {
 107                                                 string parentPath = Path.GetDirectoryName (filenames [n]);
 108                                                 if (parentPath != null && Directory.Exists (parentPath)) {
 109                                                         watcher.Path = parentPath;
 110                                                         watcher.Filter = Path.GetFileName (filenames [n]);
 111                                                 } else
 112                                                         continue;
 113                                         }
 114                                         watcher.Created += new FileSystemEventHandler (OnChanged);
 115                                         watcher.Changed += new FileSystemEventHandler (OnChanged);
 116                                         watcher.Deleted += new FileSystemEventHandler (OnChanged);
 117                                         watcher.Renamed += new RenamedEventHandler (OnChanged);
 118                                         watcher.EnableRaisingEvents = true;
 119                                         watchers [n] = watcher;
 120                                 }
 121                         }
 122 #endif
 123                         this.cachekeys = cachekeys;
 124                         this.dependency = dependency;
 125                         if (dependency != null)
 126                                 dependency.DependencyChanged += new EventHandler (OnChildDependencyChanged);
 127                         this.start = start;
 128                 }
 129
 130 #if NET_2_0
 131                 public virtual string GetUniqueID ()
 132                 {
 133                         StringBuilder sb = new StringBuilder ();
 134 #if !TARGET_JVM
 135                         lock (locker) {
 136                                 if (watchers != null)
 137                                         foreach (FileSystemWatcher fsw in watchers)
 138                                                 if (fsw != null && fsw.Path != null && fsw.Path.Length != 0)
 139                                                         sb.AppendFormat ("_{0}", fsw.Path);
 140                         }
 141 #endif
 142
 143                         if (cachekeys != null)
 144                                 foreach (string key in cachekeys)
 145                                         sb.AppendFormat ("_{0}", key);
 146                         return sb.ToString ();
 147                 }
 148 #endif
 149
 150 #if !TARGET_JVM
 151                 void OnChanged (object sender, FileSystemEventArgs args)
 152                 {
 153                         if (DateTime.Now < start)
 154                                 return;
 155                         hasChanged = true;
 156                         DisposeWatchers ();
 157
 158                         if (cache != null)
 159                                 cache.CheckExpiration ();
 160                 }
 161
 162                 void DisposeWatchers ()
 163                 {
 164                         lock (locker) {
 165                                 if (watchers != null) {
 166                                         foreach (FileSystemWatcher w in watchers)
 167                                                 if (w != null)
 168                                                         w.Dispose ();
 169                                 }
 170                                 watchers = null;
 171                         }
 172                 }
 173 #else
 174                 void DisposeWatchers ()
 175                 {
 176                 }
 177 #endif
 178                 public void Dispose ()
 179                 {
 180                         DisposeWatchers ();
 181                         if (dependency != null)
 182                                 dependency.DependencyChanged -= new EventHandler (OnChildDependencyChanged);
 183                         cache = null;
 184                 }
 185
 186                 internal void SetCache (Cache c)
 187                 {
 188                         cache = c;
 189 #if NET_2_0
 190                         used = c != null;
 191 #endif
 192                 }
 193
 194 #if NET_2_0
 195                 internal bool IsUsed {
 196                         get { return used; }
 197                 }
 198
 199                 internal DateTime Start {
 200                         get { return start; }
 201                         set { start = value; }
 202                 }
 203 #endif
 204
 205                 public bool HasChanged {
 206                         get {
 207                                 if (hasChanged)
 208                                         return true;
 209
 210                                 if (DateTime.Now < start)
 211                                         return false;
 212
 213                                 if (cache != null && cachekeys != null) {
 214                                         foreach (string key in cachekeys) {
 215                                                 if (cache.GetKeyLastChange (key) > start) {
 216                                                         hasChanged = true;
 217                                                         break;
 218                                                 }
 219                                         }
 220                                 }
 221                                 if (hasChanged)
 222                                         DisposeWatchers ();
 223
 224                                 return hasChanged;
 225                         }
 226                 }
 227
 228                 void OnChildDependencyChanged (object o, EventArgs a)
 229                 {
 230                         hasChanged = true;
 231                         OnDependencyChanged ();
 232                 }
 233
 234                 void OnDependencyChanged ()
 235                 {
 236                         if (DependencyChanged != null)
 237                                 DependencyChanged (this, null);
 238                 }
 239
 240 #if NET_2_0
 241                 internal void SignalDependencyChanged ()
 242                 {
 243                         OnDependencyChanged ();
 244                 }
 245 #endif
 246                 internal event EventHandler DependencyChanged;
 247         }
 248 }