jellyfin/MediaBrowser.Controller/IO/DirectoryWatchers.cs
2013-02-21 15:26:55 -05:00

531 lines
18 KiB
C#

using MediaBrowser.Common.IO;
using MediaBrowser.Common.Logging;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Library;
using MediaBrowser.Controller.ScheduledTasks;
using MediaBrowser.Model.Logging;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
namespace MediaBrowser.Controller.IO
{
/// <summary>
/// Class DirectoryWatchers
/// </summary>
public class DirectoryWatchers : IDisposable
{
/// <summary>
/// The file system watchers
/// </summary>
private ConcurrentBag<FileSystemWatcher> FileSystemWatchers = new ConcurrentBag<FileSystemWatcher>();
/// <summary>
/// The update timer
/// </summary>
private Timer updateTimer;
/// <summary>
/// The affected paths
/// </summary>
private readonly ConcurrentDictionary<string, string> affectedPaths = new ConcurrentDictionary<string, string>();
/// <summary>
/// A dynamic list of paths that should be ignored. Added to during our own file sytem modifications.
/// </summary>
private readonly ConcurrentDictionary<string,string> TempIgnoredPaths = new ConcurrentDictionary<string, string>(StringComparer.OrdinalIgnoreCase);
/// <summary>
/// The timer lock
/// </summary>
private readonly object timerLock = new object();
/// <summary>
/// Add the path to our temporary ignore list. Use when writing to a path within our listening scope.
/// </summary>
/// <param name="path">The path.</param>
public void TemporarilyIgnore(string path)
{
TempIgnoredPaths[path] = path;
}
/// <summary>
/// Removes the temp ignore.
/// </summary>
/// <param name="path">The path.</param>
public void RemoveTempIgnore(string path)
{
string val;
TempIgnoredPaths.TryRemove(path, out val);
}
/// <summary>
/// Gets or sets the logger.
/// </summary>
/// <value>The logger.</value>
private ILogger Logger { get; set; }
/// <summary>
/// Initializes a new instance of the <see cref="DirectoryWatchers" /> class.
/// </summary>
public DirectoryWatchers(ILogger logger)
{
if (logger == null)
{
throw new ArgumentNullException("logger");
}
Logger = logger;
}
/// <summary>
/// Starts this instance.
/// </summary>
internal void Start()
{
Kernel.Instance.LibraryManager.LibraryChanged += Instance_LibraryChanged;
var pathsToWatch = new List<string> { Kernel.Instance.RootFolder.Path };
var paths = Kernel.Instance.RootFolder.Children.OfType<Folder>()
.SelectMany(f =>
{
try
{
// Accessing ResolveArgs could involve file system access
return f.ResolveArgs.PhysicalLocations;
}
catch (IOException)
{
return new string[] {};
}
})
.Where(Path.IsPathRooted);
foreach (var path in paths)
{
if (!ContainsParentFolder(pathsToWatch, path))
{
pathsToWatch.Add(path);
}
}
foreach (var path in pathsToWatch)
{
StartWatchingPath(path);
}
}
/// <summary>
/// Examine a list of strings assumed to be file paths to see if it contains a parent of
/// the provided path.
/// </summary>
/// <param name="lst">The LST.</param>
/// <param name="path">The path.</param>
/// <returns><c>true</c> if [contains parent folder] [the specified LST]; otherwise, <c>false</c>.</returns>
/// <exception cref="System.ArgumentNullException">path</exception>
private static bool ContainsParentFolder(IEnumerable<string> lst, string path)
{
if (string.IsNullOrEmpty(path))
{
throw new ArgumentNullException("path");
}
path = path.TrimEnd(Path.DirectorySeparatorChar);
return lst.Any(str =>
{
//this should be a little quicker than examining each actual parent folder...
var compare = str.TrimEnd(Path.DirectorySeparatorChar);
return (path.Equals(compare, StringComparison.OrdinalIgnoreCase) || (path.StartsWith(compare, StringComparison.OrdinalIgnoreCase) && path[compare.Length] == Path.DirectorySeparatorChar));
});
}
/// <summary>
/// Starts the watching path.
/// </summary>
/// <param name="path">The path.</param>
private void StartWatchingPath(string path)
{
// Creating a FileSystemWatcher over the LAN can take hundreds of milliseconds, so wrap it in a Task to do them all in parallel
Task.Run(() =>
{
var newWatcher = new FileSystemWatcher(path, "*") { IncludeSubdirectories = true, InternalBufferSize = 32767 };
newWatcher.Created += watcher_Changed;
newWatcher.Deleted += watcher_Changed;
newWatcher.Renamed += watcher_Changed;
newWatcher.Changed += watcher_Changed;
newWatcher.Error += watcher_Error;
try
{
newWatcher.EnableRaisingEvents = true;
FileSystemWatchers.Add(newWatcher);
Logger.Info("Watching directory " + path);
}
catch (IOException ex)
{
Logger.ErrorException("Error watching path: {0}", ex, path);
}
catch (PlatformNotSupportedException ex)
{
Logger.ErrorException("Error watching path: {0}", ex, path);
}
});
}
/// <summary>
/// Stops the watching path.
/// </summary>
/// <param name="path">The path.</param>
private void StopWatchingPath(string path)
{
var watcher = FileSystemWatchers.FirstOrDefault(f => f.Path.Equals(path, StringComparison.OrdinalIgnoreCase));
if (watcher != null)
{
DisposeWatcher(watcher);
}
}
/// <summary>
/// Disposes the watcher.
/// </summary>
/// <param name="watcher">The watcher.</param>
private void DisposeWatcher(FileSystemWatcher watcher)
{
Logger.Info("Stopping directory watching for path {0}", watcher.Path);
watcher.EnableRaisingEvents = false;
watcher.Dispose();
var watchers = FileSystemWatchers.ToList();
watchers.Remove(watcher);
FileSystemWatchers = new ConcurrentBag<FileSystemWatcher>(watchers);
}
/// <summary>
/// Handles the LibraryChanged event of the Kernel
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="Library.ChildrenChangedEventArgs" /> instance containing the event data.</param>
void Instance_LibraryChanged(object sender, ChildrenChangedEventArgs e)
{
if (e.Folder is AggregateFolder && e.HasAddOrRemoveChange)
{
if (e.ItemsRemoved != null)
{
foreach (var item in e.ItemsRemoved.OfType<Folder>())
{
StopWatchingPath(item.Path);
}
}
if (e.ItemsAdded != null)
{
foreach (var item in e.ItemsAdded.OfType<Folder>())
{
StartWatchingPath(item.Path);
}
}
}
}
/// <summary>
/// Handles the Error event of the watcher control.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="ErrorEventArgs" /> instance containing the event data.</param>
async void watcher_Error(object sender, ErrorEventArgs e)
{
var ex = e.GetException();
var dw = (FileSystemWatcher) sender;
Logger.ErrorException("Error in Directory watcher for: "+dw.Path, ex);
if (ex.Message.Contains("network name is no longer available"))
{
//Network either dropped or, we are coming out of sleep and it hasn't reconnected yet - wait and retry
Logger.Warn("Network connection lost - will retry...");
var retries = 0;
var success = false;
while (!success && retries < 10)
{
await Task.Delay(500).ConfigureAwait(false);
try
{
dw.EnableRaisingEvents = false;
dw.EnableRaisingEvents = true;
success = true;
}
catch (IOException)
{
Logger.Warn("Network still unavailable...");
retries++;
}
}
if (!success)
{
Logger.Warn("Unable to access network. Giving up.");
DisposeWatcher(dw);
}
}
else
{
if (!ex.Message.Contains("BIOS command limit"))
{
Logger.Info("Attempting to re-start watcher.");
dw.EnableRaisingEvents = false;
dw.EnableRaisingEvents = true;
}
}
}
/// <summary>
/// Handles the Changed event of the watcher control.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="FileSystemEventArgs" /> instance containing the event data.</param>
void watcher_Changed(object sender, FileSystemEventArgs e)
{
if (e.ChangeType == WatcherChangeTypes.Created && e.Name == "New folder")
{
return;
}
if (TempIgnoredPaths.ContainsKey(e.FullPath))
{
Logger.Info("Watcher requested to ignore change to " + e.FullPath);
return;
}
Logger.Info("Watcher sees change of type " + e.ChangeType.ToString() + " to " + e.FullPath);
//Since we're watching created, deleted and renamed we always want the parent of the item to be the affected path
var affectedPath = e.FullPath;
affectedPaths.AddOrUpdate(affectedPath, affectedPath, (key, oldValue) => affectedPath);
lock (timerLock)
{
if (updateTimer == null)
{
updateTimer = new Timer(TimerStopped, null, TimeSpan.FromSeconds(Kernel.Instance.Configuration.FileWatcherDelay), TimeSpan.FromMilliseconds(-1));
}
else
{
updateTimer.Change(TimeSpan.FromSeconds(Kernel.Instance.Configuration.FileWatcherDelay), TimeSpan.FromMilliseconds(-1));
}
}
}
/// <summary>
/// Timers the stopped.
/// </summary>
/// <param name="stateInfo">The state info.</param>
private async void TimerStopped(object stateInfo)
{
lock (timerLock)
{
// Extend the timer as long as any of the paths are still being written to.
if (affectedPaths.Any(p => IsFileLocked(p.Key)))
{
Logger.Info("Timer extended.");
updateTimer.Change(TimeSpan.FromSeconds(Kernel.Instance.Configuration.FileWatcherDelay), TimeSpan.FromMilliseconds(-1));
return;
}
Logger.Info("Timer stopped.");
updateTimer.Dispose();
updateTimer = null;
}
var paths = affectedPaths.Keys.ToList();
affectedPaths.Clear();
await ProcessPathChanges(paths).ConfigureAwait(false);
}
/// <summary>
/// Try and determine if a file is locked
/// This is not perfect, and is subject to race conditions, so I'd rather not make this a re-usable library method.
/// </summary>
/// <param name="path">The path.</param>
/// <returns><c>true</c> if [is file locked] [the specified path]; otherwise, <c>false</c>.</returns>
private bool IsFileLocked(string path)
{
try
{
var data = FileSystem.GetFileData(path);
if (!data.HasValue || data.Value.IsDirectory)
{
return false;
}
}
catch (IOException)
{
return false;
}
FileStream stream = null;
try
{
stream = new FileStream(path, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
}
catch
{
//the file is unavailable because it is:
//still being written to
//or being processed by another thread
//or does not exist (has already been processed)
return true;
}
finally
{
if (stream != null)
stream.Close();
}
//file is not locked
return false;
}
/// <summary>
/// Processes the path changes.
/// </summary>
/// <param name="paths">The paths.</param>
/// <returns>Task.</returns>
private async Task ProcessPathChanges(List<string> paths)
{
var itemsToRefresh = paths.Select(Path.GetDirectoryName)
.Select(GetAffectedBaseItem)
.Where(item => item != null)
.Distinct()
.ToList();
foreach (var p in paths) Logger.Info(p + " reports change.");
// If the root folder changed, run the library task so the user can see it
if (itemsToRefresh.Any(i => i is AggregateFolder))
{
Kernel.Instance.TaskManager.CancelIfRunningAndQueue<RefreshMediaLibraryTask>();
return;
}
await Task.WhenAll(itemsToRefresh.Select(i => Task.Run(async () =>
{
Logger.Info(i.Name + " (" + i.Path + ") will be refreshed.");
try
{
await i.ChangedExternally().ConfigureAwait(false);
}
catch (IOException ex)
{
// For now swallow and log.
// Research item: If an IOException occurs, the item may be in a disconnected state (media unavailable)
// Should we remove it from it's parent?
Logger.ErrorException("Error refreshing {0}", ex, i.Name);
}
}))).ConfigureAwait(false);
}
/// <summary>
/// Gets the affected base item.
/// </summary>
/// <param name="path">The path.</param>
/// <returns>BaseItem.</returns>
private BaseItem GetAffectedBaseItem(string path)
{
BaseItem item = null;
while (item == null && !string.IsNullOrEmpty(path))
{
item = Kernel.Instance.RootFolder.FindByPath(path);
path = Path.GetDirectoryName(path);
}
if (item != null)
{
// If the item has been deleted find the first valid parent that still exists
while (!Directory.Exists(item.Path) && !File.Exists(item.Path))
{
item = item.Parent;
if (item == null)
{
break;
}
}
}
return item;
}
/// <summary>
/// Stops this instance.
/// </summary>
private void Stop()
{
Kernel.Instance.LibraryManager.LibraryChanged -= Instance_LibraryChanged;
FileSystemWatcher watcher;
while (FileSystemWatchers.TryTake(out watcher))
{
watcher.Changed -= watcher_Changed;
watcher.EnableRaisingEvents = false;
watcher.Dispose();
}
lock (timerLock)
{
if (updateTimer != null)
{
updateTimer.Dispose();
updateTimer = null;
}
}
affectedPaths.Clear();
}
/// <summary>
/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
/// </summary>
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
/// <summary>
/// Releases unmanaged and - optionally - managed resources.
/// </summary>
/// <param name="dispose"><c>true</c> to release both managed and unmanaged resources; <c>false</c> to release only unmanaged resources.</param>
protected virtual void Dispose(bool dispose)
{
if (dispose)
{
Stop();
}
}
}
}