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;
  41                 public bool IncludeSubdirs;
  42                 public bool Enabled;
  43                 public DateTime DisabledTime;
  44                 public Hashtable Files;
  45         }
  46
  47         class FileData {
  48                 public string Directory;
  49                 public FileAttributes Attributes;
  50                 public bool NotExists;
  51                 public DateTime CreationTime;
  52                 public DateTime LastWriteTime;
  53         }
  54
  55         class DefaultWatcher : IFileWatcher
  56         {
  57                 static DefaultWatcher instance;
  58                 static Thread thread;
  59                 static Hashtable watches;
  60
  61                 private DefaultWatcher ()
  62                 {
  63                 }
  64
  65                 public static bool GetInstance (out IFileWatcher watcher)
  66                 {
  67                         lock (typeof (DefaultWatcher)) {
  68                                 if (instance != null) {
  69                                         watcher = instance;
  70                                         return true;
  71                                 }
  72
  73                                 instance = new DefaultWatcher ();
  74                                 watcher = instance;
  75                                 return true;
  76                         }
  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.FileMask = fsw.MangledFilter;
 104                                 data.IncludeSubdirs = fsw.IncludeSubdirectories;
 105                                 data.Enabled = true;
 106                                 data.DisabledTime = DateTime.MaxValue;
 107                                 UpdateDataAndDispatch (data, false);
 108                         }
 109                 }
 110
 111                 public void StopDispatching (FileSystemWatcher fsw)
 112                 {
 113                         DefaultWatcherData data;
 114                         lock (watches) {
 115                                 data = (DefaultWatcherData) watches [fsw];
 116                                 if (data != null) {
 117                                         data.Enabled = false;
 118                                         data.DisabledTime = DateTime.Now;
 119                                 }
 120                         }
 121                 }
 122
 123
 124                 void Monitor ()
 125                 {
 126                         int zeroes = 0;
 127
 128                         while (true) {
 129                                 lock (watches) {
 130                                         if (watches.Count > 0) {
 131                                                 zeroes = 0;
 132                                                 ArrayList removed = null;
 133                                                 foreach (DefaultWatcherData data in watches.Values) {
 134                                                         bool remove = UpdateDataAndDispatch (data, true);
 135                                                         if (remove) {
 136                                                                 if (removed == null)
 137                                                                         removed = new ArrayList ();
 138
 139                                                                 removed.Add (data);
 140                                                         }
 141                                                 }
 142
 143                                                 if (removed != null) {
 144                                                         foreach (DefaultWatcherData data in removed)
 145                                                                 watches.Remove (data.FSW);
 146
 147                                                         removed.Clear ();
 148                                                         removed = null;
 149                                                 }
 150                                         } else {
 151                                                 zeroes++;
 152                                                 if (zeroes == 20)
 153                                                         break;
 154                                         }
 155                                 }
 156                                 Thread.Sleep (750);
 157                         }
 158
 159                         lock (this) {
 160                                 thread = null;
 161                         }
 162                 }
 163
 164                 bool UpdateDataAndDispatch (DefaultWatcherData data, bool dispatch)
 165                 {
 166                         if (!data.Enabled) {
 167                                 return (data.DisabledTime != DateTime.MaxValue &&
 168                                         (DateTime.Now - data.DisabledTime).TotalSeconds > 5);
 169                         }
 170
 171                         DoFiles (data, data.Directory, dispatch);
 172                         return false;
 173                 }
 174
 175                 static void DispatchEvents (FileSystemWatcher fsw, FileAction action, string filename)
 176                 {
 177                         RenamedEventArgs renamed = null;
 178
 179                         lock (fsw) {
 180                                 fsw.DispatchEvents (action, filename, ref renamed);
 181                                 if (fsw.Waiting) {
 182                                         fsw.Waiting = false;
 183                                         System.Threading.Monitor.PulseAll (fsw);
 184                                 }
 185                         }
 186                 }
 187
 188                 void DoFiles (DefaultWatcherData data, string directory, bool dispatch)
 189                 {
 190                         bool direxists = Directory.Exists (directory);
 191                         if (direxists && data.IncludeSubdirs) {
 192                                 foreach (string d in Directory.GetDirectories (directory))
 193                                         DoFiles (data, d, dispatch);
 194                         }
 195
 196                         string [] files = null;
 197                         if (direxists) {
 198                                 files = Directory.GetFileSystemEntries (directory, data.FileMask);
 199                         } else {
 200                                 files = new string [0];
 201                         }
 202
 203                         /* Set all as untested */
 204                         foreach (string filename in data.Files.Keys) {
 205                                 FileData fd = (FileData) data.Files [filename];
 206                                 if (fd.Directory == directory)
 207                                         fd.NotExists = true;
 208                         }
 209
 210                         /* New files */
 211                         foreach (string filename in files) {
 212                                 FileData fd = (FileData) data.Files [filename];
 213                                 if (fd == null) {
 214                                         data.Files.Add (filename, CreateFileData (directory, filename));
 215                                         if (dispatch)
 216                                                 DispatchEvents (data.FSW, FileAction.Added, filename);
 217                                 } else if (fd.Directory == directory) {
 218                                         fd.NotExists = false;
 219                                 }
 220                         }
 221
 222                         if (!dispatch) // We only initialize the file list
 223                                 return;
 224
 225                         /* Removed files */
 226                         ArrayList removed = null;
 227                         foreach (string filename in data.Files.Keys) {
 228                                 FileData fd = (FileData) data.Files [filename];
 229                                 if (fd.NotExists) {
 230                                         if (removed == null)
 231                                                 removed = new ArrayList ();
 232
 233                                         removed.Add (filename);
 234                                         DispatchEvents (data.FSW, FileAction.Removed, filename);
 235                                 }
 236                         }
 237
 238                         if (removed != null) {
 239                                 foreach (string filename in removed)
 240                                         data.Files.Remove (filename);
 241
 242                                 removed = null;
 243                         }
 244
 245                         /* Changed files */
 246                         foreach (string filename in data.Files.Keys) {
 247                                 FileData fd = (FileData) data.Files [filename];
 248                                 DateTime creation, write;
 249                                 try {
 250                                         creation = File.GetCreationTime (filename);
 251                                         write = File.GetLastWriteTime (filename);
 252                                 } catch {
 253                                         /* Deleted */
 254                                         if (removed == null)
 255                                                 removed = new ArrayList ();
 256
 257                                         removed.Add (filename);
 258                                         DispatchEvents (data.FSW, FileAction.Removed, filename);
 259                                         continue;
 260                                 }
 261
 262                                 if (creation != fd.CreationTime || write != fd.LastWriteTime) {
 263                                         fd.CreationTime = creation;
 264                                         fd.LastWriteTime = write;
 265                                         DispatchEvents (data.FSW, FileAction.Modified, filename);
 266                                 }
 267                         }
 268
 269                         if (removed != null) {
 270                                 foreach (string filename in removed)
 271                                         data.Files.Remove (filename);
 272                         }
 273
 274                 }
 275
 276                 static FileData CreateFileData (string directory, string filename)
 277                 {
 278                         FileData fd = new FileData ();
 279                         string fullpath = Path.Combine (directory, filename);
 280                         fd.Directory = directory;
 281                         fd.Attributes = File.GetAttributes (fullpath);
 282                         fd.CreationTime = File.GetCreationTime (fullpath);
 283                         fd.LastWriteTime = File.GetLastWriteTime (fullpath);
 284                         return fd;
 285                 }
 286         }
 287 }
 288