'Check if this L{FilePath} refers to a directory.
@return: C{True} if this L{FilePath} refers to a directory, C{False}
otherwise.
@rtype: L{bool}'

def isdir(self):

    st = self._statinfo
    if (not st):
        self.restat(False)
        st = self._statinfo
        if (not st):
            return False
    return S_ISDIR(st.st_mode)
