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                 public static bool GetInstance (out IFileWatcher watcher)
  67                 {
  68                         lock (typeof (DefaultWatcher)) {
  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
  80                 public void StartDispatching (FileSystemWatcher fsw)
  81                 {
  82                         DefaultWatcherData data;
  83                         lock (this) {
  84                                 if (watches == null)
  85                                         watches = new Hashtable ();
  86
  87                                 if (thread == null) {
  88                                         thread = new Thread (new ThreadStart (Monitor));
  89                                         thread.IsBackground = true;
  90                                         thread.Start ();
  91                                 }
  92                         }
  93
  94                         lock (watches) {
  95                                 data = (DefaultWatcherData) watches [fsw];
  96                                 if (data == null) {
  97                                         data = new DefaultWatcherData ();
  98                                         data.Files = new Hashtable ();
  99                                         watches [fsw] = data;
 100                                 }
 101
 102                                 data.FSW = fsw;
 103                                 data.Directory = fsw.FullPath;
 104                                 data.NoWildcards = !fsw.Pattern.HasWildcard;
 105                                 if (data.NoWildcards)
 106                                         data.FileMask = Path.Combine (data.Directory, fsw.MangledFilter);
 107                                 else
 108                                         data.FileMask = fsw.MangledFilter;
 109
 110                                 data.IncludeSubdirs = fsw.IncludeSubdirectories;
 111                                 data.Enabled = true;
 112                                 data.DisabledTime = DateTime.MaxValue;
 113                                 UpdateDataAndDispatch (data, false);
 114                         }
 115                 }
 116
 117                 public void StopDispatching (FileSystemWatcher fsw)
 118                 {
 119                         DefaultWatcherData data;
 120                         lock (watches) {
 121                                 data = (DefaultWatcherData) watches [fsw];
 122                                 if (data != null) {
 123                                         data.Enabled = false;
 124                                         data.DisabledTime = DateTime.Now;
 125                                 }
 126                         }
 127                 }
 128
 129
 130                 void Monitor ()
 131                 {
 132                         int zeroes = 0;
 133
 134                         while (true) {
 135                                 lock (watches) {
 136                                         if (watches.Count > 0) {
 137                                                 zeroes = 0;
 138                                                 ArrayList removed = null;
 139                                                 foreach (DefaultWatcherData data in watches.Values) {
 140                                                         bool remove = UpdateDataAndDispatch (data, true);
 141                                                         if (remove) {
 142                                                                 if (removed == null)
 143                                                                         removed = new ArrayList ();
 144
 145                                                                 removed.Add (data);
 146                                                         }
 147                                                 }
 148
 149                                                 if (removed != null) {
 150                                                         foreach (DefaultWatcherData data in removed)
 151                                                                 watches.Remove (data.FSW);
 152
 153                                                         removed.Clear ();
 154                                                         removed = null;
 155                                                 }
 156                                         } else {
 157                                                 zeroes++;
 158                                                 if (zeroes == 20)
 159                                                         break;
 160                                         }
 161                                 }
 162                                 Thread.Sleep (750);
 163                         }
 164
 165                         lock (this) {
 166                                 thread = null;
 167                         }
 168                 }
 169
 170                 bool UpdateDataAndDispatch (DefaultWatcherData data, bool dispatch)
 171                 {
 172                         if (!data.Enabled) {
 173                                 return (data.DisabledTime != DateTime.MaxValue &&
 174                                         (DateTime.Now - data.DisabledTime).TotalSeconds > 5);
 175                         }
 176
 177                         DoFiles (data, data.Directory, dispatch);
 178                         return false;
 179                 }
 180
 181                 static void DispatchEvents (FileSystemWatcher fsw, FileAction action, string filename)
 182                 {
 183                         RenamedEventArgs renamed = null;
 184
 185                         lock (fsw) {
 186                                 fsw.DispatchEvents (action, filename, ref renamed);
 187                                 if (fsw.Waiting) {
 188                                         fsw.Waiting = false;
 189                                         System.Threading.Monitor.PulseAll (fsw);
 190                                 }
 191                         }
 192                 }
 193
 194                 static string [] NoStringsArray = new string [0];
 195                 void DoFiles (DefaultWatcherData data, string directory, bool dispatch)
 196                 {
 197                         bool direxists = Directory.Exists (directory);
 198                         if (direxists && data.IncludeSubdirs) {
 199                                 foreach (string d in Directory.GetDirectories (directory))
 200                                         DoFiles (data, d, dispatch);
 201                         }
 202
 203                         string [] files = null;
 204                         if (!direxists) {
 205                                 files = NoStringsArray;
 206                         } else if (!data.NoWildcards) {
 207                                 files = Directory.GetFileSystemEntries (directory, data.FileMask);
 208                         } else {
 209                                 // The pattern does not have wildcards
 210                                 if (File.Exists (data.FileMask))
 211                                         files = new string [] { data.FileMask };
 212                                 else
 213                                         files = NoStringsArray;
 214                         }
 215
 216                         /* Set all as untested */
 217                         foreach (string filename in data.Files.Keys) {
 218                                 FileData fd = (FileData) data.Files [filename];
 219                                 if (fd.Directory == directory)
 220                                         fd.NotExists = true;
 221                         }
 222
 223                         /* New files */
 224                         foreach (string filename in files) {
 225                                 FileData fd = (FileData) data.Files [filename];
 226                                 if (fd == null) {
 227                                         try {
 228                                                 data.Files.Add (filename, CreateFileData (directory, filename));
 229                                         } catch {
 230                                                 // The file might have been removed in the meanwhile
 231                                                 data.Files.Remove (filename);
 232                                                 continue;
 233                                         }
 234
 235                                         if (dispatch)
 236                                                 DispatchEvents (data.FSW, FileAction.Added, filename);
 237                                 } else if (fd.Directory == directory) {
 238                                         fd.NotExists = false;
 239                                 }
 240                         }
 241
 242                         if (!dispatch) // We only initialize the file list
 243                                 return;
 244
 245                         /* Removed files */
 246                         ArrayList removed = null;
 247                         foreach (string filename in data.Files.Keys) {
 248                                 FileData fd = (FileData) data.Files [filename];
 249                                 if (fd.NotExists) {
 250                                         if (removed == null)
 251                                                 removed = new ArrayList ();
 252
 253                                         removed.Add (filename);
 254                                         DispatchEvents (data.FSW, FileAction.Removed, filename);
 255                                 }
 256                         }
 257
 258                         if (removed != null) {
 259                                 foreach (string filename in removed)
 260                                         data.Files.Remove (filename);
 261
 262                                 removed = null;
 263                         }
 264
 265                         /* Changed files */
 266                         foreach (string filename in data.Files.Keys) {
 267                                 FileData fd = (FileData) data.Files [filename];
 268                                 DateTime creation, write;
 269                                 try {
 270                                         creation = File.GetCreationTime (filename);
 271                                         write = File.GetLastWriteTime (filename);
 272                                 } catch {
 273                                         /* Deleted */
 274                                         if (removed == null)
 275                                                 removed = new ArrayList ();
 276
 277                                         removed.Add (filename);
 278                                         DispatchEvents (data.FSW, FileAction.Removed, filename);
 279                                         continue;
 280                                 }
 281
 282                                 if (creation != fd.CreationTime || write != fd.LastWriteTime) {
 283                                         fd.CreationTime = creation;
 284                                         fd.LastWriteTime = write;
 285                                         DispatchEvents (data.FSW, FileAction.Modified, filename);
 286                                 }
 287                         }
 288
 289                         if (removed != null) {
 290                                 foreach (string filename in removed)
 291                                         data.Files.Remove (filename);
 292                         }
 293
 294                 }
 295
 296                 static FileData CreateFileData (string directory, string filename)
 297                 {
 298                         FileData fd = new FileData ();
 299                         string fullpath = Path.Combine (directory, filename);
 300                         fd.Directory = directory;
 301                         fd.Attributes = File.GetAttributes (fullpath);
 302                         fd.CreationTime = File.GetCreationTime (fullpath);
 303                         fd.LastWriteTime = File.GetLastWriteTime (fullpath);
 304                         return fd;
 305                 }
 306         }
 307 }
 308