public NTStatus NotifyChange(out object ioRequest, object handle, NotifyChangeFilter completionFilter, bool watchTree, int outputBufferSize, OnNotifyChangeCompleted onNotifyChangeCompleted, object context)
{
byte[] buffer = new byte[outputBufferSize];
ManualResetEvent requestAddedEvent = new ManualResetEvent(false);
PendingRequest request = new PendingRequest();
Thread m_thread = new Thread(delegate()
{
request.FileHandle = (IntPtr)handle;
request.ThreadID = ThreadingHelper.GetCurrentThreadId();
m_pendingRequests.Add(request);
// The request has been added, we can now return STATUS_PENDING.
requestAddedEvent.Set();
NTStatus status = NtNotifyChangeDirectoryFile((IntPtr)handle, IntPtr.Zero, IntPtr.Zero, IntPtr.Zero, out request.IOStatusBlock, buffer, (uint)buffer.Length, completionFilter, watchTree);
if (status == NTStatus.STATUS_SUCCESS)
{
int length = (int)request.IOStatusBlock.Information;
buffer = ByteReader.ReadBytes(buffer, 0, length);
}
else
{
const NTStatus STATUS_ALERTED = (NTStatus)0x00000101;
const NTStatus STATUS_OBJECT_TYPE_MISMATCH = (NTStatus)0xC0000024;
buffer = new byte[0];
if (status == STATUS_OBJECT_TYPE_MISMATCH)
{
status = NTStatus.STATUS_INVALID_HANDLE;
}
else if (status == STATUS_ALERTED)
{
status = NTStatus.STATUS_CANCELLED;
}
// If the handle is closing and we had to cancel a ChangeNotify request as part of a cleanup,
// we return STATUS_NOTIFY_CLEANUP as specified in [MS-FSA] 2.1.5.4.
if (status == NTStatus.STATUS_CANCELLED && request.Cleanup)
{
status = NTStatus.STATUS_NOTIFY_CLEANUP;
}
}
onNotifyChangeCompleted(status, buffer, context);
m_pendingRequests.Remove((IntPtr)handle, request.ThreadID);
});
m_thread.Start();
// We must wait for the request to be added in order for Cancel to function properly.
requestAddedEvent.WaitOne();
ioRequest = request;
return(NTStatus.STATUS_PENDING);
}
public void Add(PendingRequest request)
{
lock (m_handleToNotifyChangeRequests)
{
List <PendingRequest> pendingRequests;
bool containsKey = m_handleToNotifyChangeRequests.TryGetValue(request.FileHandle, out pendingRequests);
if (containsKey)
{
pendingRequests.Add(request);
}
else
{
pendingRequests = new List <PendingRequest>();
pendingRequests.Add(request);
m_handleToNotifyChangeRequests.Add(request.FileHandle, pendingRequests);
}
}
}
public NTStatus Cancel(object ioRequest)
{
PendingRequest request = (PendingRequest)ioRequest;
const uint THREAD_TERMINATE = 0x00000001;
const uint THREAD_ALERT = 0x00000004;
uint threadID = request.ThreadID;
IntPtr threadHandle = ThreadingHelper.OpenThread(THREAD_TERMINATE | THREAD_ALERT, false, threadID);
if (threadHandle == IntPtr.Zero)
{
Win32Error error = (Win32Error)Marshal.GetLastWin32Error();
if (error == Win32Error.ERROR_INVALID_PARAMETER)
{
return(NTStatus.STATUS_INVALID_HANDLE);
}
else
{
throw new Exception("OpenThread failed, Win32 error: " + error.ToString("D"));
}
}
NTStatus status;
if (Environment.OSVersion.Version.Major >= 6)
{
IO_STATUS_BLOCK ioStatusBlock;
status = NtCancelSynchronousIoFile(threadHandle, ref request.IOStatusBlock, out ioStatusBlock);
}
else
{
// The handle was opened for synchronous operation so NtNotifyChangeDirectoryFile is blocking.
// We MUST use NtAlertThread to send a signal to stop the wait. The handle cannot be closed otherwise.
// Note: The handle was opened with CreateOptions.FILE_SYNCHRONOUS_IO_ALERT as required.
status = NtAlertThread(threadHandle);
}
ThreadingHelper.CloseHandle(threadHandle);
m_pendingRequests.Remove(request.FileHandle, request.ThreadID);
return(status);
}
