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                 protected
  60                 CacheDependency (): this (null, null, null, DateTime.Now)
  61                 {
  62                 }
  63
  64                 public CacheDependency (string filename): this (new string[] { filename }, null, null, DateTime.Now)
  65                 {
  66                 }
  67
  68                 public CacheDependency (string[] filenames): this (filenames, null, null, DateTime.Now)
  69                 {
  70                 }
  71
  72                 public CacheDependency (string filename, DateTime start): this (new string[] { filename }, null, null, start)
  73                 {
  74                 }
  75
  76                 public CacheDependency (string [] filenames, DateTime start)
  77                         : this (filenames, null, null, start)
  78                 {
  79                 }
  80
  81                 public CacheDependency (string[] filenames, string[] cachekeys): this (filenames, cachekeys, null, DateTime.Now)
  82                 {
  83                 }
  84
  85                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency): this (filenames, cachekeys, dependency, DateTime.Now)
  86                 {
  87                 }
  88
  89                 public CacheDependency (string[] filenames, string[] cachekeys, DateTime start): this (filenames, cachekeys, null, start)
  90                 {
  91                 }
  92
  93                 public CacheDependency (string[] filenames, string[] cachekeys, CacheDependency dependency, DateTime start)
  94                 {
  95                         int flen = filenames != null ? filenames.Length : 0;
  96
  97                         if (flen > 0) {
  98                                 watchers = new FileSystemWatcher [flen];
  99                                 string filename;
 100
 101                                 for (int n = 0; n < flen; n++) {
 102                                         filename = filenames [n];
 103                                         if (String.IsNullOrEmpty (filename))
 104                                                 continue;
 105
 106                                         FileSystemWatcher watcher = new FileSystemWatcher ();
 107                                         if (Directory.Exists (filename))
 108                                                 watcher.Path = filename;
 109                                         else {
 110                                                 string parentPath = Path.GetDirectoryName (filename);
 111                                                 if (parentPath != null && Directory.Exists (parentPath)) {
 112                                                         watcher.Path = parentPath;
 113                                                         watcher.Filter = Path.GetFileName (filename);
 114                                                 } else
 115                                                         continue;
 116                                         }
 117                                         watcher.NotifyFilter |= NotifyFilters.Size;
 118                                         watcher.Created += new FileSystemEventHandler (OnChanged);
 119                                         watcher.Changed += new FileSystemEventHandler (OnChanged);
 120                                         watcher.Deleted += new FileSystemEventHandler (OnChanged);
 121                                         watcher.Renamed += new RenamedEventHandler (OnChanged);
 122                                         watcher.EnableRaisingEvents = true;
 123                                         watchers [n] = watcher;
 124                                 }
 125                         }
 126                         this.cachekeys = cachekeys;
 127                         this.dependency = dependency;
 128                         if (dependency != null)
 129                                 dependency.DependencyChanged += new EventHandler (OnChildDependencyChanged);
 130                         this.start = start;
 131
 132                         FinishInit ();
 133                 }
 134
 135                 public virtual string GetUniqueID ()
 136                 {
 137                         var sb = new StringBuilder ();
 138
 139                         lock (locker) {
 140                                 if (watchers != null)
 141                                         foreach (FileSystemWatcher fsw in watchers)
 142                                                 if (fsw != null && fsw.Path != null && fsw.Path.Length != 0)
 143                                                         sb.Append ("_" + fsw.Path);
 144                         }
 145
 146                         if (cachekeys != null)
 147                                 foreach (string key in cachekeys)
 148                                         sb.AppendFormat ("_" + key);
 149                         return sb.ToString ();
 150                 }
 151
 152                 void OnChanged (object sender, FileSystemEventArgs args)
 153                 {
 154                         OnDependencyChanged (sender, args);
 155                 }
 156
 157                 bool DoOnChanged ()
 158                 {
 159                         DateTime now = DateTime.Now;
 160
 161                         if (now < start)
 162                                 return false;
 163                         hasChanged = true;
 164                         utcLastModified = now.ToUniversalTime ();
 165                         DisposeWatchers ();
 166
 167                         if (cache != null)
 168                                 cache.CheckDependencies ();
 169
 170                         return true;
 171                 }
 172
 173                 void DisposeWatchers ()
 174                 {
 175                         lock (locker) {
 176                                 if (watchers != null) {
 177                                         foreach (FileSystemWatcher w in watchers)
 178                                                 if (w != null)
 179                                                         w.Dispose ();
 180                                 }
 181                                 watchers = null;
 182                         }
 183                 }
 184
 185                 public void Dispose ()
 186                 {
 187                         DependencyDispose ();
 188                 }
 189
 190                 internal virtual void DependencyDisposeInternal ()
 191                 {
 192                 }
 193
 194                 protected virtual void DependencyDispose ()
 195                 {
 196                         DependencyDisposeInternal ();
 197                         DisposeWatchers ();
 198                         if (dependency != null) {
 199                                 dependency.DependencyChanged -= new EventHandler (OnChildDependencyChanged);
 200                                 dependency.Dispose ();
 201                         }
 202
 203                         cache = null;
 204                 }
 205
 206                 internal void SetCache (Cache c)
 207                 {
 208                         cache = c;
 209                         used = c != null;
 210                 }
 211
 212                 protected internal void FinishInit ()
 213                 {
 214                         utcLastModified = DateTime.UtcNow;
 215                 }
 216
 217                 internal bool IsUsed {
 218                         get { return used; }
 219                 }
 220
 221                 internal DateTime Start {
 222                         get { return start; }
 223                         set { start = value; }
 224                 }
 225
 226                 public DateTime UtcLastModified {
 227                         get {
 228                                 return utcLastModified;
 229                         }
 230                 }
 231
 232                 protected void SetUtcLastModified (DateTime utcLastModified)
 233                 {
 234                         this.utcLastModified = utcLastModified;
 235                 }
 236
 237                 public bool HasChanged {
 238                         get {
 239                                 if (hasChanged)
 240                                         return true;
 241
 242                                 if (DateTime.Now < start)
 243                                         return false;
 244
 245                                 if (cache != null && cachekeys != null) {
 246                                         foreach (string key in cachekeys) {
 247                                                 if (cache.GetKeyLastChange (key) > start) {
 248                                                         hasChanged = true;
 249                                                         break;
 250                                                 }
 251                                         }
 252                                 }
 253                                 if (hasChanged)
 254                                         DisposeWatchers ();
 255
 256                                 return hasChanged;
 257                         }
 258                 }
 259
 260                 void OnChildDependencyChanged (object o, EventArgs e)
 261                 {
 262                         hasChanged = true;
 263                         OnDependencyChanged (o, e);
 264                 }
 265
 266                 void OnDependencyChanged (object sender, EventArgs e)
 267                 {
 268                         if (!DoOnChanged ())
 269                                 return;
 270
 271                         EventHandler eh = events [dependencyChangedEvent] as EventHandler;
 272                         if (eh != null)
 273                                 eh (sender, e);
 274                 }
 275
 276                 protected void NotifyDependencyChanged (object sender, EventArgs e)
 277                 {
 278                         OnDependencyChanged (sender, e);
 279                 }
 280         }
 281 }