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                 DateTime utcLastModified;
  58 #endif
  59                 object locker = new object ();
  60
  61 #if NET_2_0
  62                 public CacheDependency (): this (null, null, null, DateTime.Now)
  63                 {
  64                 }
  65 #endif
  66
  67                 public CacheDependency (string filename): this (new string[] { filename }, null, null, DateTime.Now)
  68                 {
  69                 }
  70
  71                 public CacheDependency (string[] filenames): this (filenames, null, null, DateTime.Now)
  72                 {
  73                 }
  74
  75                 public CacheDependency (string filename, DateTime start): this (new string[] { filename }, null, null, start)
  76                 {
  77                 }
  78
  79                 public CacheDependency (string [] filenames, DateTime start)
  80                         : this (filenames, null, null, start)
  81                 {
  82                 }
  83
  84                 public CacheDependency (string[] filenames, string[] cachekeys): this (filenames, cachekeys, null, DateTime.Now)
  85                 {
  86                 }
  87
  88                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency): this (filenames, cachekeys, dependency, DateTime.Now)
  89                 {
  90                 }
  91
  92                 public CacheDependency (string[] filenames, string[] cachekeys, DateTime start): this (filenames, cachekeys, null, start)
  93                 {
  94                 }
  95
  96                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency, DateTime start)
  97                 {
  98                         if (filenames != null) {
  99                                 watchers = new FileSystemWatcher [filenames.Length];
 100                                 for (int n=0; n<filenames.Length; n++) {
 101                                         FileSystemWatcher watcher = new FileSystemWatcher ();
 102                                         if (Directory.Exists (filenames [n])) {
 103                                                 watcher.Path = filenames [n];
 104                                         } else {
 105                                                 string parentPath = Path.GetDirectoryName (filenames [n]);
 106                                                 if (parentPath != null && Directory.Exists (parentPath)) {
 107                                                         watcher.Path = parentPath;
 108                                                         watcher.Filter = Path.GetFileName (filenames [n]);
 109                                                 } else
 110                                                         continue;
 111                                         }
 112                                         watcher.NotifyFilter |= NotifyFilters.Size;
 113                                         watcher.Created += new FileSystemEventHandler (OnChanged);
 114                                         watcher.Changed += new FileSystemEventHandler (OnChanged);
 115                                         watcher.Deleted += new FileSystemEventHandler (OnChanged);
 116                                         watcher.Renamed += new RenamedEventHandler (OnChanged);
 117                                         watcher.EnableRaisingEvents = true;
 118                                         watchers [n] = watcher;
 119                                 }
 120                         }
 121                         this.cachekeys = cachekeys;
 122                         this.dependency = dependency;
 123                         if (dependency != null)
 124                                 dependency.DependencyChanged += new EventHandler (OnChildDependencyChanged);
 125                         this.start = start;
 126
 127 #if NET_2_0
 128                         FinishInit ();
 129 #endif
 130                 }
 131
 132 #if NET_2_0
 133                 public virtual string GetUniqueID ()
 134                 {
 135                         StringBuilder sb = new StringBuilder ();
 136                         lock (locker) {
 137                                 if (watchers != null)
 138                                         foreach (FileSystemWatcher fsw in watchers)
 139                                                 if (fsw != null && fsw.Path != null && fsw.Path.Length != 0)
 140                                                         sb.AppendFormat ("_{0}", fsw.Path);
 141                         }
 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                 void OnChanged (object sender, FileSystemEventArgs args)
 151                 {
 152                         OnDependencyChanged (sender, args);
 153                 }
 154
 155                 bool DoOnChanged ()
 156                 {
 157                         if (DateTime.Now < start)
 158                                 return false;
 159                         hasChanged = true;
 160 #if NET_2_0
 161                         utcLastModified = DateTime.UtcNow;
 162 #endif
 163                         DisposeWatchers ();
 164
 165                         if (cache != null)
 166                                 cache.CheckExpiration ();
 167
 168                         return true;
 169                 }
 170
 171                 void DisposeWatchers ()
 172                 {
 173                         lock (locker) {
 174                                 if (watchers != null) {
 175                                         foreach (FileSystemWatcher w in watchers)
 176                                                 if (w != null)
 177                                                         w.Dispose ();
 178                                 }
 179                                 watchers = null;
 180                         }
 181                 }
 182
 183                 public void Dispose ()
 184                 {
 185                         DependencyDispose ();
 186                 }
 187
 188 #if NET_2_0
 189                 internal virtual void DependencyDisposeInternal ()
 190                 {
 191                 }
 192 #endif
 193
 194 #if NET_2_0
 195                 protected virtual
 196 #endif
 197                 void DependencyDispose ()
 198                 {
 199 #if NET_2_0
 200                         DependencyDisposeInternal ();
 201 #endif
 202                         DisposeWatchers ();
 203                         if (dependency != null)
 204                                 dependency.DependencyChanged -= new EventHandler (OnChildDependencyChanged);
 205                         cache = null;
 206                 }
 207
 208                 internal void SetCache (Cache c)
 209                 {
 210                         cache = c;
 211 #if NET_2_0
 212                         used = c != null;
 213 #endif
 214                 }
 215
 216 #if NET_2_0
 217                 protected internal void FinishInit ()
 218                 {
 219                         utcLastModified = DateTime.UtcNow;
 220                 }
 221
 222                 internal bool IsUsed {
 223                         get { return used; }
 224                 }
 225
 226                 internal DateTime Start {
 227                         get { return start; }
 228                         set { start = value; }
 229                 }
 230
 231                 public DateTime UtcLastModified {
 232                         get {
 233                                 return utcLastModified;
 234                         }
 235                 }
 236
 237                 protected void SetUtcLastModified (DateTime utcLastModified)
 238                 {
 239                         this.utcLastModified = utcLastModified;
 240                 }
 241 #endif
 242
 243                 public bool HasChanged {
 244                         get {
 245                                 if (hasChanged)
 246                                         return true;
 247
 248                                 if (DateTime.Now < start)
 249                                         return false;
 250
 251                                 if (cache != null && cachekeys != null) {
 252                                         foreach (string key in cachekeys) {
 253                                                 if (cache.GetKeyLastChange (key) > start) {
 254                                                         hasChanged = true;
 255                                                         break;
 256                                                 }
 257                                         }
 258                                 }
 259                                 if (hasChanged)
 260                                         DisposeWatchers ();
 261
 262                                 return hasChanged;
 263                         }
 264                 }
 265
 266                 void OnChildDependencyChanged (object o, EventArgs e)
 267                 {
 268                         hasChanged = true;
 269                         OnDependencyChanged (o, e);
 270                 }
 271
 272                 void OnDependencyChanged (object sender, EventArgs e)
 273                 {
 274                         if (!DoOnChanged ())
 275                                 return;
 276
 277                         if (DependencyChanged == null)
 278                                 return;
 279
 280                         foreach (EventHandler eh in DependencyChanged.GetInvocationList ())
 281                                 eh (sender, e);
 282                 }
 283
 284 #if NET_2_0
 285                 protected
 286 #else
 287                 internal
 288 #endif
 289                 void NotifyDependencyChanged (object sender, EventArgs e)
 290                 {
 291                         OnDependencyChanged (sender, e);
 292                 }
 293
 294                 internal event EventHandler DependencyChanged;
 295         }
 296 }