code.grnet.gr Git - pithos-ms-client/blob - trunk/Pithos.Core/Agents/FileWatcherAgent.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.ComponentModel.Composition;
   4 using System.Diagnostics;
   5 using System.IO;
   6 using System.Linq;
   7 using System.Text;
   8 using Pithos.Interfaces;
   9
  10 namespace Pithos.Core.Agents
  11 {
  12     [Export]
  13     public class FileWatcherAgent
  14     {
  15         Agent<WorkflowState> _agent;
  16         private FileSystemWatcher _watcher;
  17
  18         [Import]
  19         public IStatusKeeper StatusKeeper { get; set; }
  20         [Import]
  21         public IPithosWorkflow Workflow { get; set; }
  22         [Import]
  23         public WorkflowAgent WorkflowAgent { get; set; }
  24
  25         public void Start(string path)
  26         {
  27             _watcher = new FileSystemWatcher(path);
  28             _watcher.Changed += OnFileEvent;
  29             _watcher.Created += OnFileEvent;
  30             _watcher.Deleted += OnFileEvent;
  31             _watcher.Renamed += OnRenameEvent;
  32             _watcher.EnableRaisingEvents = true;
  33
  34
  35             _agent = Agent<WorkflowState>.Start(inbox =>
  36             {
  37                 Action loop = null;
  38                 loop = () =>
  39                 {
  40                     var message = inbox.Receive();
  41                     var process = message.ContinueWith(t =>
  42                     {
  43                         var state = t.Result;
  44                         Process(state);
  45                         inbox.DoAsync(loop);
  46                     });
  47
  48                     process.ContinueWith(t =>
  49                     {
  50                         inbox.DoAsync(loop);
  51                         if (t.IsFaulted)
  52                         {
  53                             var ex = t.Exception.InnerException;
  54                             if (ex is OperationCanceledException)
  55                                 inbox.Stop();
  56                             Trace.TraceError("[ERROR] File Event Processing:\r{0}", ex);
  57                         }
  58                     });
  59
  60                 };
  61                 loop();
  62             });
  63         }
  64
  65         public bool Pause
  66         {
  67             get { return _watcher == null || !_watcher.EnableRaisingEvents; }
  68             set
  69             {
  70                 if (_watcher != null)
  71                     _watcher.EnableRaisingEvents = !value;
  72             }
  73         }
  74
  75         public void Post(WorkflowState workflowState)
  76         {
  77             _agent.Post(workflowState);
  78         }
  79
  80         public void Stop()
  81         {
  82             if (_watcher != null)
  83             {
  84                 _watcher.Changed -= OnFileEvent;
  85                 _watcher.Created -= OnFileEvent;
  86                 _watcher.Deleted -= OnFileEvent;
  87                 _watcher.Renamed -= OnRenameEvent;
  88                 _watcher.Dispose();
  89             }
  90             _watcher = null;
  91
  92             _agent.Stop();
  93         }
  94
  95         void OnFileEvent(object sender, FileSystemEventArgs e)
  96         {
  97             _agent.Post(new WorkflowState { Path = e.FullPath, FileName = e.Name, TriggeringChange = e.ChangeType });
  98         }
  99
 100         void OnRenameEvent(object sender, RenamedEventArgs e)
 101         {
 102             _agent.Post(new WorkflowState
 103             {
 104                 OldPath = e.OldFullPath,
 105                 OldFileName = e.OldName,
 106                 Path = e.FullPath,
 107                 FileName = e.Name,
 108                 TriggeringChange = e.ChangeType
 109             });
 110         }
 111
 112
 113         private void Process(WorkflowState state)
 114         {
 115             var networkState = StatusKeeper.GetNetworkState(state.Path);
 116             //Skip if the file is already being downloaded or uploaded and
 117             //the change is create or modify
 118             if (networkState != NetworkState.None &&
 119                 (
 120                     state.TriggeringChange == WatcherChangeTypes.Created ||
 121                     state.TriggeringChange == WatcherChangeTypes.Changed
 122                 ))
 123                 return;
 124             UpdateFileStatus(state);
 125             UpdateOverlayStatus(state);
 126             UpdateFileChecksum(state);
 127             WorkflowAgent.Post(state);
 128         }
 129
 130         private Dictionary<WatcherChangeTypes, FileStatus> _statusDict = new Dictionary<WatcherChangeTypes, FileStatus>
 131         {
 132             {WatcherChangeTypes.Created,FileStatus.Created},
 133             {WatcherChangeTypes.Changed,FileStatus.Modified},
 134             {WatcherChangeTypes.Deleted,FileStatus.Deleted},
 135             {WatcherChangeTypes.Renamed,FileStatus.Renamed}
 136         };
 137
 138         private WorkflowState UpdateFileStatus(WorkflowState state)
 139         {
 140             string path = state.Path;
 141             FileStatus status = _statusDict[state.TriggeringChange];
 142             var oldStatus = Workflow.StatusKeeper.GetFileStatus(path);
 143             if (status == oldStatus)
 144             {
 145                 state.Status = status;
 146                 state.Skip = true;
 147                 return state;
 148             }
 149             if (state.Status == FileStatus.Renamed)
 150                 Workflow.ClearFileStatus(path);
 151
 152             state.Status = Workflow.SetFileStatus(path, status);
 153             return state;
 154         }
 155
 156         private WorkflowState UpdateOverlayStatus(WorkflowState state)
 157         {
 158             if (state.Skip)
 159                 return state;
 160
 161             switch (state.Status)
 162             {
 163                 case FileStatus.Created:
 164                 case FileStatus.Modified:
 165                     this.StatusKeeper.SetFileOverlayStatus(state.Path, FileOverlayStatus.Modified);
 166                     break;
 167                 case FileStatus.Deleted:
 168                     this.StatusKeeper.RemoveFileOverlayStatus(state.Path);
 169                     break;
 170                 case FileStatus.Renamed:
 171                     this.StatusKeeper.RemoveFileOverlayStatus(state.OldPath);
 172                     this.StatusKeeper.SetFileOverlayStatus(state.Path, FileOverlayStatus.Modified);
 173                     break;
 174                 case FileStatus.Unchanged:
 175                     this.StatusKeeper.SetFileOverlayStatus(state.Path, FileOverlayStatus.Normal);
 176                     break;
 177             }
 178
 179             if (state.Status == FileStatus.Deleted)
 180                 Workflow.RaiseChangeNotification(Path.GetDirectoryName(state.Path));
 181             else
 182                 Workflow.RaiseChangeNotification(state.Path);
 183             return state;
 184         }
 185
 186
 187         private WorkflowState UpdateFileChecksum(WorkflowState state)
 188         {
 189             if (state.Skip)
 190                 return state;
 191
 192             if (state.Status == FileStatus.Deleted)
 193                 return state;
 194
 195             string path = state.Path;
 196             string hash = Signature.CalculateMD5(path);
 197
 198             StatusKeeper.UpdateFileChecksum(path, hash);
 199
 200             state.Hash = hash;
 201             return state;
 202         }
 203
 204
 205
 206
 207     }
 208 }