100 lines
5.0 KiB
C#
100 lines
5.0 KiB
C#
using System.Reactive.Linq;
|
|
using System.Reactive.Concurrency;
|
|
|
|
namespace StarsAssistant.Helpers;
|
|
|
|
public static class FsWatcher
|
|
{
|
|
/// <summary>
|
|
/// Helper to convert a FileSystemWatcher into an obervable stream. See FileSystemWatcher
|
|
/// documentation for further details on the parameters.
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// Curtesy of https://endjin.com/blog/2024/05/observe-file-system-changes-with-rx-dotnet
|
|
/// </remarks>
|
|
/// <param name="directoryPath">The base directory to watch over.</param>
|
|
/// <param name="filters">An optional list of filter expressions to look for, default is no filter.</param>
|
|
/// <param name="includeSubdirectories">Scan subdirectories, default is exclude subdirs</param>
|
|
/// <param name="notifyFilter">Set this to override the default event selection to filter.</param>
|
|
/// <returns>An observable for further use, usually throttled by Quiescent.</returns>
|
|
public static IObservable<FileSystemEventArgs> ObserveFileSystem(
|
|
string directoryPath,
|
|
IEnumerable<string>? filters = null,
|
|
bool includeSubdirectories = false,
|
|
NotifyFilters? notifyFilter = null)
|
|
{
|
|
return
|
|
// Observable.Defer enables us to avoid doing any work
|
|
// until we have a subscriber.
|
|
Observable.Defer(() =>
|
|
{
|
|
FileSystemWatcher fsw = new(directoryPath);
|
|
if (filters != null)
|
|
foreach (string filter in filters)
|
|
fsw.Filters.Add(filter);
|
|
|
|
if (notifyFilter != null)
|
|
fsw.NotifyFilter = (NotifyFilters) notifyFilter;
|
|
fsw.EnableRaisingEvents = true;
|
|
fsw.IncludeSubdirectories = includeSubdirectories;
|
|
|
|
return Observable.Return(fsw);
|
|
})
|
|
// Once the preceding part emits the FileSystemWatcher
|
|
// (which will happen when someone first subscribes), we
|
|
// want to wrap all the events as IObservable<T>s, for which
|
|
// we'll use a projection. To avoid ending up with an
|
|
// IObservable<IObservable<FileSystemEventArgs>>, we use
|
|
// SelectMany, which effectively flattens it by one level.
|
|
.SelectMany(fsw =>
|
|
Observable.Merge(new[]
|
|
{
|
|
Observable.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
|
|
h => fsw.Created += h, h => fsw.Created -= h),
|
|
Observable.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
|
|
h => fsw.Changed += h, h => fsw.Changed -= h),
|
|
Observable.FromEventPattern<RenamedEventHandler, FileSystemEventArgs>(
|
|
h => fsw.Renamed += h, h => fsw.Renamed -= h),
|
|
Observable.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
|
|
h => fsw.Deleted += h, h => fsw.Deleted -= h)
|
|
})
|
|
// FromEventPattern supplies both the sender and the event
|
|
// args. Extract just the latter.
|
|
.Select(ep => ep.EventArgs)
|
|
// The Finally here ensures the watcher gets shut down once
|
|
// we have no subscribers.
|
|
.Finally(fsw.Dispose))
|
|
// This combination of Publish and RefCount means that multiple
|
|
// subscribers will get to share a single FileSystemWatcher,
|
|
// but that it gets shut down if all subscribers unsubscribe.
|
|
.Publish()
|
|
.RefCount();
|
|
}
|
|
|
|
/// <summary>
|
|
/// Throttle a FileSystemObserver and eliminate all duplicates.
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// Curtesy of https://endjin.com/blog/2024/05/observe-file-system-changes-with-rx-dotnet
|
|
/// </remarks>
|
|
/// <param name="watcher">An observer created with <c>ObserveFileSystem</c></param>
|
|
/// <param name="inactivitySeconds">Throttling window, defaults to 1 second.</param>
|
|
/// <param name="scheduler">Scheduler to user for throttling, default is set by <c>Quiescent</c></param>
|
|
/// <returns>A throttled observer with duplicate elimination.</returns>
|
|
public static IObservable<FileSystemEventArgs> ThrottleAndDistinct (
|
|
this IObservable<FileSystemEventArgs> watcher,
|
|
int inactivitySeconds = 1,
|
|
IScheduler? scheduler = null)
|
|
{
|
|
return watcher
|
|
.Quiescent(TimeSpan.FromSeconds(inactivitySeconds), scheduler)
|
|
.SelectMany(
|
|
changes => changes
|
|
.DistinctBy(x => (x.ChangeType, x.FullPath))
|
|
.ToObservable()
|
|
)
|
|
;
|
|
}
|
|
|
|
}
|