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 using System.Collections;
  30 using System.ComponentModel;
  31 using System.IO;
  32 using System.Security.Permissions;
  33 using System.Text;
  34
  35 namespace System.Web.Caching
  36 {
  37         // CAS
  38         [AspNetHostingPermission (SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  39         [AspNetHostingPermission (SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
  40         public class CacheDependency: IDisposable
  41         {
  42                 static readonly object dependencyChangedEvent = new object ();
  43                 string[] cachekeys;
  44                 CacheDependency dependency;
  45                 DateTime start;
  46                 Cache cache;
  47                 FileSystemWatcher[] watchers;
  48                 bool hasChanged;
  49                 bool used;
  50                 DateTime utcLastModified;
  51                 object locker = new object ();
  52                 EventHandlerList events = new EventHandlerList ();
  53
  54                 internal event EventHandler DependencyChanged {
  55                         add { events.AddHandler (dependencyChangedEvent, value); }
  56                         remove { events.RemoveHandler (dependencyChangedEvent, value); }
  57                 }
  58
  59                 public CacheDependency (): this (null, null, null, DateTime.Now)
  60                 {
  61                 }
  62
  63                 public CacheDependency (string filename): this (new string[] { filename }, null, null, DateTime.Now)
  64                 {
  65                 }
  66
  67                 public CacheDependency (string[] filenames): this (filenames, null, null, DateTime.Now)
  68                 {
  69                 }
  70
  71                 public CacheDependency (string filename, DateTime start): this (new string[] { filename }, null, null, start)
  72                 {
  73                 }
  74
  75                 public CacheDependency (string [] filenames, DateTime start)
  76                         : this (filenames, null, null, start)
  77                 {
  78                 }
  79
  80                 public CacheDependency (string[] filenames, string[] cachekeys): this (filenames, cachekeys, null, DateTime.Now)
  81                 {
  82                 }
  83
  84                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency): this (filenames, cachekeys, dependency, DateTime.Now)
  85                 {
  86                 }
  87
  88                 public CacheDependency (string[] filenames, string[] cachekeys, DateTime start): this (filenames, cachekeys, null, start)
  89                 {
  90                 }
  91
  92                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency, DateTime start)
  93                 {
  94                         if (filenames != null) {
  95                                 watchers = new FileSystemWatcher [filenames.Length];
  96                                 for (int n=0; n<filenames.Length; n++) {
  97                                         FileSystemWatcher watcher = new FileSystemWatcher ();
  98                                         if (Directory.Exists (filenames [n])) {
  99                                                 watcher.Path = filenames [n];
 100                                         } else {
 101                                                 string parentPath = Path.GetDirectoryName (filenames [n]);
 102                                                 if (parentPath != null && Directory.Exists (parentPath)) {
 103                                                         watcher.Path = parentPath;
 104                                                         watcher.Filter = Path.GetFileName (filenames [n]);
 105                                                 } else
 106                                                         continue;
 107                                         }
 108                                         watcher.NotifyFilter |= NotifyFilters.Size;
 109                                         watcher.Created += new FileSystemEventHandler (OnChanged);
 110                                         watcher.Changed += new FileSystemEventHandler (OnChanged);
 111                                         watcher.Deleted += new FileSystemEventHandler (OnChanged);
 112                                         watcher.Renamed += new RenamedEventHandler (OnChanged);
 113                                         watcher.EnableRaisingEvents = true;
 114                                         watchers [n] = watcher;
 115                                 }
 116                         }
 117                         this.cachekeys = cachekeys;
 118                         this.dependency = dependency;
 119                         if (dependency != null)
 120                                 dependency.DependencyChanged += new EventHandler (OnChildDependencyChanged);
 121                         this.start = start;
 122
 123                         FinishInit ();
 124                 }
 125
 126                 public virtual string GetUniqueID ()
 127                 {
 128                         StringBuilder sb = new StringBuilder ();
 129                         lock (locker) {
 130                                 if (watchers != null)
 131                                         foreach (FileSystemWatcher fsw in watchers)
 132                                                 if (fsw != null && fsw.Path != null && fsw.Path.Length != 0)
 133                                                         sb.AppendFormat ("_{0}", fsw.Path);
 134                         }
 135
 136                         if (cachekeys != null)
 137                                 foreach (string key in cachekeys)
 138                                         sb.AppendFormat ("_{0}", key);
 139                         return sb.ToString ();
 140                 }
 141
 142                 void OnChanged (object sender, FileSystemEventArgs args)
 143                 {
 144                         OnDependencyChanged (sender, args);
 145                 }
 146
 147                 bool DoOnChanged ()
 148                 {
 149                         if (DateTime.Now < start)
 150                                 return false;
 151                         hasChanged = true;
 152                         utcLastModified = DateTime.UtcNow;
 153                         DisposeWatchers ();
 154
 155                         if (cache != null)
 156                                 cache.CheckDependencies ();
 157
 158                         return true;
 159                 }
 160
 161                 void DisposeWatchers ()
 162                 {
 163                         lock (locker) {
 164                                 if (watchers != null) {
 165                                         foreach (FileSystemWatcher w in watchers)
 166                                                 if (w != null)
 167                                                         w.Dispose ();
 168                                 }
 169                                 watchers = null;
 170                         }
 171                 }
 172
 173                 public void Dispose ()
 174                 {
 175                         DependencyDispose ();
 176                 }
 177
 178                 internal virtual void DependencyDisposeInternal ()
 179                 {
 180                 }
 181
 182                 protected virtual void DependencyDispose ()
 183                 {
 184                         DependencyDisposeInternal ();
 185                         DisposeWatchers ();
 186                         if (dependency != null) {
 187                                 dependency.DependencyChanged -= new EventHandler (OnChildDependencyChanged);
 188                                 dependency.Dispose ();
 189                         }
 190
 191                         cache = null;
 192                 }
 193
 194                 internal void SetCache (Cache c)
 195                 {
 196                         cache = c;
 197                         used = c != null;
 198                 }
 199
 200                 protected internal void FinishInit ()
 201                 {
 202                         utcLastModified = DateTime.UtcNow;
 203                 }
 204
 205                 internal bool IsUsed {
 206                         get { return used; }
 207                 }
 208
 209                 internal DateTime Start {
 210                         get { return start; }
 211                         set { start = value; }
 212                 }
 213
 214                 public DateTime UtcLastModified {
 215                         get {
 216                                 return utcLastModified;
 217                         }
 218                 }
 219
 220                 protected void SetUtcLastModified (DateTime utcLastModified)
 221                 {
 222                         this.utcLastModified = utcLastModified;
 223                 }
 224
 225                 public bool HasChanged {
 226                         get {
 227                                 if (hasChanged)
 228                                         return true;
 229
 230                                 if (DateTime.Now < start)
 231                                         return false;
 232
 233                                 if (cache != null && cachekeys != null) {
 234                                         foreach (string key in cachekeys) {
 235                                                 if (cache.GetKeyLastChange (key) > start) {
 236                                                         hasChanged = true;
 237                                                         break;
 238                                                 }
 239                                         }
 240                                 }
 241                                 if (hasChanged)
 242                                         DisposeWatchers ();
 243
 244                                 return hasChanged;
 245                         }
 246                 }
 247
 248                 void OnChildDependencyChanged (object o, EventArgs e)
 249                 {
 250                         hasChanged = true;
 251                         OnDependencyChanged (o, e);
 252                 }
 253
 254                 void OnDependencyChanged (object sender, EventArgs e)
 255                 {
 256                         if (!DoOnChanged ())
 257                                 return;
 258
 259                         EventHandler eh = events [dependencyChangedEvent] as EventHandler;
 260                         if (eh != null)
 261                                 eh (sender, e);
 262                 }
 263
 264                 protected void NotifyDependencyChanged (object sender, EventArgs e)
 265                 {
 266                         OnDependencyChanged (sender, e);
 267                 }
 268
 269
 270         }
 271 }