mcs/class/System/System.IO/DefaultWatcher.cs

   1 //
   2 // System.IO.DefaultWatcher.cs: default IFileWatcher
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //
   7 // (c) 2004 Novell, Inc. (http://www.novell.com)
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using System.Collections;
  33 using System.IO;
  34 using System.Threading;
  35
  36 namespace System.IO {
  37         class DefaultWatcherData {
  38                 public FileSystemWatcher FSW;
  39                 public string Directory;
  40                 public string FileMask; // If NoWildcards, contains the full path to the file.
  41                 public bool IncludeSubdirs;
  42                 public bool Enabled;
  43                 public bool NoWildcards;
  44                 public DateTime DisabledTime;
  45                 public Hashtable Files;
  46         }
  47
  48         class FileData {
  49                 public string Directory;
  50                 public FileAttributes Attributes;
  51                 public bool NotExists;
  52                 public DateTime CreationTime;
  53                 public DateTime LastWriteTime;
  54         }
  55
  56         class DefaultWatcher : IFileWatcher
  57         {
  58                 static DefaultWatcher instance;
  59                 static Thread thread;
  60                 static Hashtable watches;
  61
  62                 private DefaultWatcher ()
  63                 {
  64                 }
  65
  66                 // Locked by caller
  67                 public static bool GetInstance (out IFileWatcher watcher)
  68                 {
  69                         if (instance != null) {
  70                                 watcher = instance;
  71                                 return true;
  72                         }
  73
  74                         instance = new DefaultWatcher ();
  75                         watcher = instance;
  76                         return true;
  77                 }
  78
  79                 public void StartDispatching (FileSystemWatcher fsw)
  80                 {
  81                         DefaultWatcherData data;
  82                         lock (this) {
  83                                 if (watches == null)
  84                                         watches = new Hashtable ();
  85
  86                                 if (thread == null) {
  87                                         thread = new Thread (new ThreadStart (Monitor));
  88                                         thread.IsBackground = true;
  89                                         thread.Start ();
  90                                 }
  91                         }
  92
  93                         lock (watches) {
  94                                 data = (DefaultWatcherData) watches [fsw];
  95                                 if (data == null) {
  96                                         data = new DefaultWatcherData ();
  97                                         data.Files = new Hashtable ();
  98                                         watches [fsw] = data;
  99                                 }
 100
 101                                 data.FSW = fsw;
 102                                 data.Directory = fsw.FullPath;
 103                                 data.NoWildcards = !fsw.Pattern.HasWildcard;
 104                                 if (data.NoWildcards)
 105                                         data.FileMask = Path.Combine (data.Directory, fsw.MangledFilter);
 106                                 else
 107                                         data.FileMask = fsw.MangledFilter;
 108
 109                                 data.IncludeSubdirs = fsw.IncludeSubdirectories;
 110                                 data.Enabled = true;
 111                                 data.DisabledTime = DateTime.MaxValue;
 112                                 UpdateDataAndDispatch (data, false);
 113                         }
 114                 }
 115
 116                 public void StopDispatching (FileSystemWatcher fsw)
 117                 {
 118                         DefaultWatcherData data;
 119                         lock (this) {
 120                                 if (watches == null) return;
 121                         }
 122
 123                         lock (watches) {
 124                                 data = (DefaultWatcherData) watches [fsw];
 125                                 if (data != null) {
 126                                         data.Enabled = false;
 127                                         data.DisabledTime = DateTime.Now;
 128                                 }
 129                         }
 130                 }
 131
 132
 133                 void Monitor ()
 134                 {
 135                         int zeroes = 0;
 136
 137                         while (true) {
 138                                 Thread.Sleep (750);
 139
 140                                 Hashtable my_watches;
 141                                 lock (watches) {
 142                                         if (watches.Count == 0) {
 143                                                 if (++zeroes == 20)
 144                                                         break;
 145                                                 continue;
 146                                         }
 147
 148                                         my_watches = (Hashtable) watches.Clone ();
 149                                 }
 150
 151                                 if (my_watches.Count != 0) {
 152                                         zeroes = 0;
 153                                         foreach (DefaultWatcherData data in my_watches.Values) {
 154                                                 bool remove = UpdateDataAndDispatch (data, true);
 155                                                 if (remove)
 156                                                         lock (watches)
 157                                                                 watches.Remove (data.FSW);
 158                                         }
 159                                 }
 160                         }
 161
 162                         lock (this) {
 163                                 thread = null;
 164                         }
 165                 }
 166
 167                 bool UpdateDataAndDispatch (DefaultWatcherData data, bool dispatch)
 168                 {
 169                         if (!data.Enabled) {
 170                                 return (data.DisabledTime != DateTime.MaxValue &&
 171                                         (DateTime.Now - data.DisabledTime).TotalSeconds > 5);
 172                         }
 173
 174                         DoFiles (data, data.Directory, dispatch);
 175                         return false;
 176                 }
 177
 178                 static void DispatchEvents (FileSystemWatcher fsw, FileAction action, string filename)
 179                 {
 180                         RenamedEventArgs renamed = null;
 181
 182                         lock (fsw) {
 183                                 fsw.DispatchEvents (action, filename, ref renamed);
 184                                 if (fsw.Waiting) {
 185                                         fsw.Waiting = false;
 186                                         System.Threading.Monitor.PulseAll (fsw);
 187                                 }
 188                         }
 189                 }
 190
 191                 static string [] NoStringsArray = new string [0];
 192                 void DoFiles (DefaultWatcherData data, string directory, bool dispatch)
 193                 {
 194                         bool direxists = Directory.Exists (directory);
 195                         if (direxists && data.IncludeSubdirs) {
 196                                 foreach (string d in Directory.GetDirectories (directory))
 197                                         DoFiles (data, d, dispatch);
 198                         }
 199
 200                         string [] files = null;
 201                         if (!direxists) {
 202                                 files = NoStringsArray;
 203                         } else if (!data.NoWildcards) {
 204                                 files = Directory.GetFileSystemEntries (directory, data.FileMask);
 205                         } else {
 206                                 // The pattern does not have wildcards
 207                                 if (File.Exists (data.FileMask) || Directory.Exists (data.FileMask))
 208                                         files = new string [] { data.FileMask };
 209                                 else
 210                                         files = NoStringsArray;
 211                         }
 212
 213                         /* Set all as untested */
 214                         foreach (string filename in data.Files.Keys) {
 215                                 FileData fd = (FileData) data.Files [filename];
 216                                 if (fd.Directory == directory)
 217                                         fd.NotExists = true;
 218                         }
 219
 220                         /* New files */
 221                         foreach (string filename in files) {
 222                                 FileData fd = (FileData) data.Files [filename];
 223                                 if (fd == null) {
 224                                         try {
 225                                                 data.Files.Add (filename, CreateFileData (directory, filename));
 226                                         } catch {
 227                                                 // The file might have been removed in the meanwhile
 228                                                 data.Files.Remove (filename);
 229                                                 continue;
 230                                         }
 231
 232                                         if (dispatch)
 233                                                 DispatchEvents (data.FSW, FileAction.Added, filename);
 234                                 } else if (fd.Directory == directory) {
 235                                         fd.NotExists = false;
 236                                 }
 237                         }
 238
 239                         if (!dispatch) // We only initialize the file list
 240                                 return;
 241
 242                         /* Removed files */
 243                         ArrayList removed = null;
 244                         foreach (string filename in data.Files.Keys) {
 245                                 FileData fd = (FileData) data.Files [filename];
 246                                 if (fd.NotExists) {
 247                                         if (removed == null)
 248                                                 removed = new ArrayList ();
 249
 250                                         removed.Add (filename);
 251                                         DispatchEvents (data.FSW, FileAction.Removed, filename);
 252                                 }
 253                         }
 254
 255                         if (removed != null) {
 256                                 foreach (string filename in removed)
 257                                         data.Files.Remove (filename);
 258
 259                                 removed = null;
 260                         }
 261
 262                         /* Changed files */
 263                         foreach (string filename in data.Files.Keys) {
 264                                 FileData fd = (FileData) data.Files [filename];
 265                                 DateTime creation, write;
 266                                 try {
 267                                         creation = File.GetCreationTime (filename);
 268                                         write = File.GetLastWriteTime (filename);
 269                                 } catch {
 270                                         /* Deleted */
 271                                         if (removed == null)
 272                                                 removed = new ArrayList ();
 273
 274                                         removed.Add (filename);
 275                                         DispatchEvents (data.FSW, FileAction.Removed, filename);
 276                                         continue;
 277                                 }
 278
 279                                 if (creation != fd.CreationTime || write != fd.LastWriteTime) {
 280                                         fd.CreationTime = creation;
 281                                         fd.LastWriteTime = write;
 282                                         DispatchEvents (data.FSW, FileAction.Modified, filename);
 283                                 }
 284                         }
 285
 286                         if (removed != null) {
 287                                 foreach (string filename in removed)
 288                                         data.Files.Remove (filename);
 289                         }
 290
 291                 }
 292
 293                 static FileData CreateFileData (string directory, string filename)
 294                 {
 295                         FileData fd = new FileData ();
 296                         string fullpath = Path.Combine (directory, filename);
 297                         fd.Directory = directory;
 298                         fd.Attributes = File.GetAttributes (fullpath);
 299                         fd.CreationTime = File.GetCreationTime (fullpath);
 300                         fd.LastWriteTime = File.GetLastWriteTime (fullpath);
 301                         return fd;
 302                 }
 303         }
 304 }
 305