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Added a background file system watcher.

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This commit is contained in:
Michael Bucari-Tovo 2021-07-27 10:13:37 -06:00
parent efca1f9c1d
commit f5e1667368
2 changed files with 130 additions and 6 deletions
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29
FileManager/AudibleFileStorage.cs
View File

@ -41,6 +41,8 @@ namespace FileManager
return Directory.CreateDirectory(Configuration.Instance.Books).FullName;
}
}
private static BackgroundFileSystem BookDirectoryFiles { get; } = new BackgroundFileSystem();
#endregion
#region instance
@ -53,7 +55,7 @@ namespace FileManager
{
extensions_noDots = Extensions.Select(ext => ext.Trim('.')).ToList();
extAggr = extensions_noDots.Aggregate((a, b) => $"{a}|{b}");
}
}
/// <summary>
/// Example for full books:
@ -63,16 +65,31 @@ namespace FileManager
/// </summary>
public bool Exists(string productId) => GetPath(productId) != null;
public string GetPath(string productId)
public string GetPath(string productId)
{
var cachedFile = FilePathCache.GetPath(productId, FileType);
if (cachedFile != null)
return cachedFile;
var firstOrNull =
Directory
.EnumerateFiles(StorageDirectory, "*.*", SearchOption.AllDirectories)
.FirstOrDefault(s => Regex.IsMatch(s, $@"{productId}.*?\.({extAggr})$", RegexOptions.IgnoreCase));
string storageDir = StorageDirectory;
string regexPattern = $@"{productId}.*?\.({extAggr})$";
string firstOrNull;
if (storageDir == BooksDirectory)
{
//If user changed the BooksDirectory, reinitialize.
if (storageDir != BookDirectoryFiles.RootDirectory)
BookDirectoryFiles.Init(storageDir, "*.*", SearchOption.AllDirectories);
firstOrNull = BookDirectoryFiles.FindFile(regexPattern, RegexOptions.IgnoreCase);
}
else
{
firstOrNull =
Directory
.EnumerateFiles(storageDir, "*.*", SearchOption.AllDirectories)
.FirstOrDefault(s => Regex.IsMatch(s, regexPattern, RegexOptions.IgnoreCase));
}
if (firstOrNull is null)
return null;

107
FileManager/BackgroundFileSystem.cs Normal file
View File

@ -0,0 +1,107 @@
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
namespace FileManager
{
class BackgroundFileSystem
{
public string RootDirectory { get; private set; }
public string SearchPattern { get; private set; }
public SearchOption SearchOption { get; private set; }
private FileSystemWatcher fileSystemWatcher { get; set; }
private BlockingCollection<FileSystemEventArgs> directoryChangesEvents { get; set; }
private Task backgroundScanner { get; set; }
private List<string> fsCache { get; set; }
public string FindFile(string regexPattern, RegexOptions options) =>
fsCache.FirstOrDefault(s => Regex.IsMatch(s, regexPattern, options));
public void Init(string rootDirectory, string searchPattern, SearchOption searchOptions)
{
RootDirectory = rootDirectory;
SearchPattern = searchPattern;
SearchOption = searchOptions;
//Calling CompleteAdding() will cause background scanner to terminate.
directoryChangesEvents?.CompleteAdding();
fsCache?.Clear();
directoryChangesEvents?.Dispose();
fileSystemWatcher?.Dispose();
fsCache = Directory.EnumerateFiles(RootDirectory, SearchPattern, SearchOption).ToList();
directoryChangesEvents = new BlockingCollection<FileSystemEventArgs>();
fileSystemWatcher = new FileSystemWatcher(RootDirectory);
fileSystemWatcher.Created += FileSystemWatcher_Changed;
fileSystemWatcher.Deleted += FileSystemWatcher_Changed;
fileSystemWatcher.Renamed += FileSystemWatcher_Changed;
fileSystemWatcher.Error += FileSystemWatcher_Error;
fileSystemWatcher.IncludeSubdirectories = true;
fileSystemWatcher.EnableRaisingEvents = true;
//Wait for background scanner to terminate before reinitializing.
backgroundScanner?.Wait();
backgroundScanner = new Task(BackgroundScanner);
backgroundScanner.Start();
}
private void FileSystemWatcher_Error(object sender, ErrorEventArgs e)
{
Init(RootDirectory, SearchPattern, SearchOption);
}
private void FileSystemWatcher_Changed(object sender, FileSystemEventArgs e)
{
directoryChangesEvents.Add(e);
}
private void UpdateLocalCache(FileSystemEventArgs change)
{
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);
}
}
private void RemovePath(string path)
{
var pathsToRemove = fsCache.Where(p => p.StartsWith(path)).ToArray();
foreach (var p in pathsToRemove)
fsCache.Remove(p);
}
private void AddPath(string path)
{
if (File.GetAttributes(path).HasFlag(FileAttributes.Directory))
fsCache.AddRange(Directory.EnumerateFiles(path, SearchPattern, SearchOption));
else
fsCache.Add(path);
}
private void BackgroundScanner()
{
while (directoryChangesEvents.TryTake(out FileSystemEventArgs change, -1))
UpdateLocalCache(change);
}
}
}