FileChangeNotificationSystemEntry.cs :  » 2.6.4-mono-.net-core » System.Runtime » System » Runtime » Caching » C# / CSharp Open Source

//
// FileChangeNotificationSystemEntry.cs
//
// Authors:
//      Marek Habersack <mhabersack@novell.com>
//
// Copyright (C) 2010 Novell, Inc. (http://novell.com/)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Caching.Hosting;
using System.Text;

namespace System.Runtime.Caching{
  // This class is NOT thread-safe - the caller needs to assure access serialization when
  // calling Add/Remove
  sealed class FileChangeNotificationSystemEntry : IDisposable
  {
    string watchedDirPath;
    FileChangeNotificationSystem owner;
    FileSystemWatcher watcher;
    SortedDictionary <string, bool> filePaths;

    SortedDictionary <string, bool> FilePaths {
      get {
        if (filePaths == null)
          filePaths = new SortedDictionary <string, bool> (Helpers.StringComparer);
        return filePaths;
      }
    }

    public bool IsEmpty {
      get { return (filePaths == null || filePaths.Count == 0); }
    }
    
    public FileChangeNotificationSystemEntry (string dirPath, FileChangeNotificationSystem owner)
    {
      if (String.IsNullOrEmpty (dirPath))
        throw new ArgumentNullException ("dirPath");

      if (owner == null)
        throw new ArgumentNullException ("owner");
      
      watchedDirPath = dirPath;
      this.owner = owner;
    }
    
    public void Add (string filePath)
    {
      if (String.IsNullOrEmpty (filePath))
        return;

      bool start = false;
      try {
        if (watcher == null) {
          watcher = new FileSystemWatcher (watchedDirPath);
          watcher.IncludeSubdirectories = false;
          watcher.Filter = String.Empty;
          watcher.NotifyFilter = NotifyFilters.FileName |
            NotifyFilters.DirectoryName |
            NotifyFilters.Size |
            NotifyFilters.LastWrite |
            NotifyFilters.CreationTime;
          watcher.Changed += OnChanged;
          watcher.Created += OnChanged;
          watcher.Deleted += OnChanged;
          watcher.Renamed += OnRenamed;
        } else if (watcher.EnableRaisingEvents) {
          Stop ();
          start = true;
        }
      
        SortedDictionary <string, bool> filePaths = FilePaths;
        if (filePaths.ContainsKey (filePath))
          return;

        filePaths.Add (filePath, true);
      } finally {
        if (start)
          Start ();
      }
    }

    public void Remove (string filePath)
    {
      if (filePath == null)
        return;

      bool start = false;
      try {
        if (watcher != null && watcher.EnableRaisingEvents) {
          Stop ();
          start = true;
        }
        
        SortedDictionary <string, bool> filePaths = FilePaths;
        if (!filePaths.ContainsKey (filePath))
          return;

        filePaths.Remove (filePath);
      } finally {
        if (start)
          Start ();
      }
    }
    
    public void Start ()
    {
      if (watcher == null)
        return;

      watcher.EnableRaisingEvents = true;
    }

    public void Stop ()
    {
      if (watcher == null)
        return;

      watcher.EnableRaisingEvents = false;
    }

    public void Dispose ()
    {
      if (watcher == null)
        return;

      try {
        Stop ();
      } finally {  
        watcher.Dispose ();
      }
    }

    void IDisposable.Dispose ()
    {
      Dispose ();
    }
    
    void OnChanged (object source, FileSystemEventArgs e)
    {
      string fullPath = e.FullPath;
      if (owner == null || filePaths == null || !filePaths.ContainsKey (fullPath))
        return;
      
      owner.OnChanged (e.ChangeType, fullPath, null);
    }

    void OnRenamed (object source, RenamedEventArgs e)
    {
      string fullPath = e.FullPath;
      if (owner == null || filePaths == null || !filePaths.ContainsKey (fullPath))
        return;

      owner.OnChanged (e.ChangeType, e.OldFullPath, e.FullPath);
    }
  }
}