| /IO/FileSystemWatcher.cs |
|---|
| @@ -0,0 +1,73 @@ |
|---|
| using System; |
| using System.IO; |
| using System.Runtime.Caching; |
| |
| namespace wasSharpNET.IO |
| { |
| /// <summary> |
| /// Filesystem watcher that ensures events are not fired twice |
| /// </summary> |
| /// <remarks>derived from Ben Hall @ benhall.io</remarks> |
| public class FileSystemWatcher : IDisposable |
| { |
| public event FileSystemEventHandler FilesytemEvent; |
| private readonly CacheItemPolicy _cacheItemPolicy; |
| private readonly int _cacheTimeMilliseconds = 1000; |
| private readonly MemoryCache _memCache; |
| |
| public FileSystemWatcher(string path, NotifyFilters notifyFilters, string filter) |
| { |
| _memCache = MemoryCache.Default; |
| |
| var watcher = new System.IO.FileSystemWatcher |
| { |
| Path = path, |
| NotifyFilter = notifyFilters, |
| Filter = filter |
| }; |
| |
| _cacheItemPolicy = new CacheItemPolicy |
| { |
| RemovedCallback = OnRemovedFromCache |
| }; |
| |
| watcher.Changed += OnChanged; |
| watcher.EnableRaisingEvents = true; |
| } |
| |
| public FileSystemWatcher(string path, NotifyFilters notifyFilters, string filter, int timeout) : this(path, |
| notifyFilters, filter) |
| { |
| _cacheTimeMilliseconds = timeout; |
| } |
| |
| // Add file event to cache for CacheTimeMilliseconds |
| private void OnChanged(object source, FileSystemEventArgs e) |
| { |
| _cacheItemPolicy.AbsoluteExpiration = |
| DateTimeOffset.Now.AddMilliseconds(_cacheTimeMilliseconds); |
| |
| // Only add if it is not there already (swallow others) |
| _memCache.AddOrGetExisting(e.Name, e, _cacheItemPolicy); |
| } |
| |
| // Handle cache item expiring |
| private void OnRemovedFromCache(CacheEntryRemovedArguments args) |
| { |
| if (args.RemovedReason != CacheEntryRemovedReason.Expired) return; |
| |
| // Now actually handle file event. |
| OnFileSystemEvent((FileSystemEventArgs)args.CacheItem.Value); |
| } |
| |
| protected virtual void OnFileSystemEvent(FileSystemEventArgs e) |
| { |
| FilesytemEvent?.Invoke(this, e); |
| } |
| |
| public void Dispose() |
| { |
| _memCache.Dispose(); |
| } |
| } |
| } |
