private void CancellationCallback()
{
if (!_stopping && _eventStream != null)
{
_stopping = true;
try
{
// When we get here, we've requested to stop so cleanup the EventStream and unschedule from the RunLoop
Interop.EventStream.FSEventStreamStop(_eventStream);
}
finally
{
StaticWatcherRunLoopManager.UnscheduleFromRunLoop(_eventStream);
}
}
}
internal unsafe void Start()
{
// Make sure _fullPath doesn't contain a link or alias
// since the OS will give back the actual, non link'd or alias'd paths
_fullDirectory = Interop.Sys.RealPath(_fullDirectory);
if (_fullDirectory == null)
{
throw Interop.GetExceptionForIoErrno(Interop.Sys.GetLastErrorInfo(), _fullDirectory, true);
}
Debug.Assert(string.IsNullOrEmpty(_fullDirectory) == false, "Watch directory is null or empty");
// Normalize the _fullDirectory path to have a trailing slash
if (_fullDirectory[_fullDirectory.Length - 1] != '/')
{
_fullDirectory += "/";
}
// Get the path to watch and verify we created the CFStringRef
SafeCreateHandle path = Interop.CoreFoundation.CFStringCreateWithCString(_fullDirectory);
if (path.IsInvalid)
{
throw Interop.GetExceptionForIoErrno(Interop.Sys.GetLastErrorInfo(), _fullDirectory, true);
}
// Take the CFStringRef and put it into an array to pass to the EventStream
SafeCreateHandle arrPaths = Interop.CoreFoundation.CFArrayCreate(new CFStringRef[1] {
path.DangerousGetHandle()
}, (UIntPtr)1);
if (arrPaths.IsInvalid)
{
path.Dispose();
throw Interop.GetExceptionForIoErrno(Interop.Sys.GetLastErrorInfo(), _fullDirectory, true);
}
// Create the callback for the EventStream if it wasn't previously created for this instance.
if (_callback == null)
{
_callback = new Interop.EventStream.FSEventStreamCallback(FileSystemEventCallback);
}
_context = ExecutionContext.Capture();
// Make sure the OS file buffer(s) are fully flushed so we don't get events from cached I/O
Interop.Sys.Sync();
// Create the event stream for the path and tell the stream to watch for file system events.
_eventStream = Interop.EventStream.FSEventStreamCreate(
_callback,
arrPaths,
Interop.EventStream.kFSEventStreamEventIdSinceNow,
0.0f,
EventStreamFlags);
if (_eventStream.IsInvalid)
{
arrPaths.Dispose();
path.Dispose();
throw Interop.GetExceptionForIoErrno(Interop.Sys.GetLastErrorInfo(), _fullDirectory, true);
}
StaticWatcherRunLoopManager.ScheduleEventStream(_eventStream);
bool started = Interop.EventStream.FSEventStreamStart(_eventStream);
if (!started)
{
// Try to get the Watcher to raise the error event; if we can't do that, just silently exit since the watcher is gone anyway
FileSystemWatcher watcher;
if (_weakWatcher.TryGetTarget(out watcher))
{
// An error occurred while trying to start the run loop so fail out
watcher.OnError(new ErrorEventArgs(new IOException(SR.EventStream_FailedToStart, Marshal.GetLastWin32Error())));
}
}
}
