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Improved BackgroundFileSystem thread safety

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This commit is contained in:
Michael Bucari-Tovo 2021-08-14 00:25:32 -06:00
parent 52fb0a27ce
commit f74b0d78db
3 changed files with 73 additions and 52 deletions
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110
FileManager/BackgroundFileSystem.cs
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@ -18,12 +18,19 @@ namespace FileManager
private FileSystemWatcher fileSystemWatcher { get; set; }
private BlockingCollection<FileSystemEventArgs> directoryChangesEvents { get; set; }
private Task backgroundScanner { get; set; }
private List<string> fsCache { get; set; }
private List<string> fsCache { get; } = new();
public BackgroundFileSystem(string rootDirectory, string searchPattern, SearchOption searchOptions)
{
RootDirectory = rootDirectory;
SearchPattern = searchPattern;
SearchOption = searchOptions;
Init();
}
public string FindFile(string regexPattern, RegexOptions options)
{
if (fsCache is null) return null;
lock (fsCache)
{
return fsCache.FirstOrDefault(s => Regex.IsMatch(s, regexPattern, options));
@ -32,8 +39,6 @@ namespace FileManager
public void RefreshFiles()
{
if (fsCache is null) return;
lock (fsCache)
{
fsCache.Clear();
@ -41,19 +46,12 @@ namespace FileManager
}
}
public void Init(string rootDirectory, string searchPattern, SearchOption searchOptions)
private void Init()
{
RootDirectory = rootDirectory;
SearchPattern = searchPattern;
SearchOption = searchOptions;
Stop();
//Calling CompleteAdding() will cause background scanner to terminate.
directoryChangesEvents?.CompleteAdding();
fsCache?.Clear();
directoryChangesEvents?.Dispose();
fileSystemWatcher?.Dispose();
fsCache = Directory.EnumerateFiles(RootDirectory, SearchPattern, SearchOption).ToList();
lock (fsCache)
fsCache.AddRange(Directory.EnumerateFiles(RootDirectory, SearchPattern, SearchOption));
directoryChangesEvents = new BlockingCollection<FileSystemEventArgs>();
fileSystemWatcher = new FileSystemWatcher(RootDirectory);
@ -64,28 +62,31 @@ namespace FileManager
fileSystemWatcher.IncludeSubdirectories = true;
fileSystemWatcher.EnableRaisingEvents = true;
//Wait for background scanner to terminate before reinitializing.
backgroundScanner?.Wait();
backgroundScanner = new Task(BackgroundScanner);
backgroundScanner.Start();
}
private void Stop()
{
//Stop raising events
fileSystemWatcher?.Dispose();
private void AddUniqueFiles(IEnumerable<string> newFiles)
{
foreach (var file in newFiles)
{
AddUniqueFile(file);
}
}
private void AddUniqueFile(string newFile)
{
if (!fsCache.Contains(newFile))
fsCache.Add(newFile);
//Calling CompleteAdding() will cause background scanner to terminate.
directoryChangesEvents?.CompleteAdding();
//Wait for background scanner to terminate before reinitializing.
backgroundScanner?.Wait();
//Dispose of directoryChangesEvents after backgroundScanner exists.
directoryChangesEvents?.Dispose();
lock (fsCache)
fsCache.Clear();
}
private void FileSystemWatcher_Error(object sender, ErrorEventArgs e)
{
Init(RootDirectory, SearchPattern, SearchOption);
Stop();
Init();
}
private void FileSystemWatcher_Changed(object sender, FileSystemEventArgs e)
@ -97,28 +98,26 @@ namespace FileManager
private void BackgroundScanner()
{
while (directoryChangesEvents.TryTake(out FileSystemEventArgs change, -1))
UpdateLocalCache(change);
{
lock (fsCache)
UpdateLocalCache(change);
}
}
private void UpdateLocalCache(FileSystemEventArgs change)
private void UpdateLocalCache(FileSystemEventArgs change)
{
lock (fsCache)
if (change.ChangeType == WatcherChangeTypes.Deleted)
{
if (change.ChangeType == WatcherChangeTypes.Deleted)
{
RemovePath(change.FullPath);
}
else if (change.ChangeType == WatcherChangeTypes.Created)
{
AddPath(change.FullPath);
}
else if (change.ChangeType == WatcherChangeTypes.Renamed)
{
var renameChange = change as RenamedEventArgs;
RemovePath(renameChange.OldFullPath);
AddPath(renameChange.FullPath);
}
RemovePath(change.FullPath);
}
else if (change.ChangeType == WatcherChangeTypes.Created)
{
AddPath(change.FullPath);
}
else if (change.ChangeType == WatcherChangeTypes.Renamed && change is RenamedEventArgs renameChange)
{
RemovePath(renameChange.OldFullPath);
AddPath(renameChange.FullPath);
}
}
@ -137,6 +136,21 @@ namespace FileManager
else
AddUniqueFile(path);
}
private void AddUniqueFiles(IEnumerable<string> newFiles)
{
foreach (var file in newFiles)
{
AddUniqueFile(file);
}
}
private void AddUniqueFile(string newFile)
{
if (!fsCache.Contains(newFile))
fsCache.Add(newFile);
}
#endregion
~BackgroundFileSystem() => Stop();
}
}