text: """
  In order to detect a filehandle that's been closed, our only clue may be
  the operating system returning the same filehandle in response to some
  other  operation.
  
  The builtins 'file' and 'open' are patched to collaborate with the
  notify_opened protocol.
  """
  
  builtins_orig = __builtins__
  
  from eventlet import hubs
  from eventlet.hubs import hub
  from eventlet.patcher import slurp_properties
  import sys
  
  __all__ = dir(builtins_orig)
  __patched__ = ['file', 'open']
  
  slurp_properties(builtins_orig, globals(),
      ignore=__patched__, srckeys=dir(builtins_orig))
  
  hubs.get_hub()
  
  __original_file = file
  class file(__original_file):
      def __init__(self, *args, **kwargs):
          super(file, self).__init__(*args, **kwargs)
          hubs.notify_opened(self.fileno())
  
  __original_open = open
  __opening = False
  def open(*args):
      global __opening
      result = __original_open(*args)
      if not __opening:
          # This is incredibly ugly. 'open' is used under the hood by
          # the import process. So, ensure we don't wind up in an
          # infinite loop.
          __opening = True
          hubs.notify_opened(result.fileno())
          __opening = False
      return result