import os, sys

import winerror
import win32file
import win32con

if __name__ == '__main__':
  path_to_watch = sys.argv[1]
  hDir = win32file.CreateFile (
    path_to_watch,
    1, # FILE_LIST_DIRECTORY
    win32con.FILE_SHARE_READ | win32con.FILE_SHARE_WRITE,
    None,
    win32con.OPEN_EXISTING,
    win32con.FILE_FLAG_BACKUP_SEMANTICS,
    None
  )
  print "=> Watching", path_to_watch

  watching = set ()
  handles = []
  try:
    while 1:
      results = win32file.ReadDirectoryChangesW (
        hDir, 1024, True,
        win32con.FILE_NOTIFY_CHANGE_FILE_NAME,
        None, None
      )
      for action, filename in results:
        filename = os.path.join (path_to_watch, filename)
        if action == 1 and filename not in watching:
          try:
            handle = win32file.CreateFile (
              filename,
              0, win32file.FILE_SHARE_DELETE,
              None, win32file.OPEN_EXISTING, 0, 0
            )
            handles.append (handle)
          except win32file.error, (errno, module, message):
            if errno == winerror.ERROR_SHARING_VIOLATION:
              print ".. Can't hold", repr (filename)
            else:
              print ".. Problem with %r: %s" % (filename, message)
          else:
            watching.add (filename)
            print ".. Holding", repr (filename)
            handle.Close ()
            handles.remove (handle)
            watching.discard (filename)
            print ".. Released", repr (filename)

  finally:
    for handle in handles:
      handle.Close ()

  hDir.Close ()