beagled/FileSystemQueryable/TreeCrawlTask.cs

   1 //
   2 // TreeCrawlTask.cs
   3 //
   4 // Copyright (C) 2005 Novell, Inc.
   5 //
   6
   7 //
   8 // Permission is hereby granted, free of charge, to any person obtaining a copy
   9 // of this software and associated documentation files (the "Software"), to deal
  10 // in the Software without restriction, including without limitation the rights
  11 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12 // copies of the Software, and to permit persons to whom the Software is
  13 // furnished to do so, subject to the following conditions:
  14 //
  15 // The above copyright notice and this permission notice shall be included in all
  16 // copies or substantial portions of the Software.
  17 //
  18 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24 // SOFTWARE.
  25 //
  26
  27 using System;
  28 using System.Collections;
  29 using System.IO;
  30
  31 using Beagle.Daemon;
  32 using Beagle.Util;
  33
  34 namespace Beagle.Daemon.FileSystemQueryable {
  35
  36         public class TreeCrawlTask : Scheduler.Task {
  37
  38                 public delegate void Handler (DirectoryModel parent, string name);
  39
  40                 private object big_lock = new object ();
  41                 private bool is_active = false;
  42                 private Handler handler;
  43                 private Queue to_be_crawled = new Queue ();
  44
  45                 public TreeCrawlTask (Handler handler)
  46                 {
  47                         this.handler = handler;
  48                         this.Tag = "Tree Crawler";
  49                         this.Priority = Scheduler.Priority.Delayed;
  50                 }
  51
  52                 public bool IsActive {
  53                         get { lock (big_lock) return is_active; }
  54                 }
  55
  56                 // Returns 'true' if the queue was empty before adding
  57                 // this item.
  58                 public bool Add (DirectoryModel dir)
  59                 {
  60                         lock (big_lock) {
  61                                 bool was_empty;
  62                                 was_empty = (to_be_crawled.Count == 0);
  63
  64                                 if (!was_empty && to_be_crawled.Contains (dir))
  65                                         return false;
  66
  67                                 to_be_crawled.Enqueue (dir);
  68                                 Description = String.Format ("Pending directories: {0}", to_be_crawled.Count);
  69                                 return was_empty;
  70                         }
  71                 }
  72
  73                 override protected void DoTaskReal ()
  74                 {
  75                         DirectoryModel dir;
  76
  77                         lock (big_lock) {
  78                                 if (to_be_crawled.Count == 0) {
  79                                         is_active = false;
  80                                         return;
  81                                 }
  82                                 dir = to_be_crawled.Dequeue () as DirectoryModel;
  83                                 is_active = true;
  84                         }
  85
  86                         if (dir.IsAttached) {
  87                                 if (FileSystemQueryable.Debug)
  88                                         Logger.Log.Debug ("Scanning '{0}' for subdirectories", dir.FullName);
  89
  90                                 try {
  91                                         foreach (string name in DirectoryWalker.GetDirectoryNames (dir.FullName))
  92                                                 handler (dir, name);
  93                                 } catch (DirectoryNotFoundException ex) {
  94                                         Logger.Log.Debug ("Couldn't scan '{0}' for subdirectories", dir.FullName);
  95                                 }
  96                         }
  97
  98                         lock (big_lock) {
  99                                 if (to_be_crawled.Count != 0)
 100                                         Reschedule = true;
 101                                 else
 102                                         is_active = false;
 103                         }
 104                 }
 105         }
 106 }