def currentframe():
    """Return the frame object for the caller's stack frame."""
    try:
        raise Exception
    except:
        return sys.exc_info()[2].tb_frame.f_back
def findCaller(self):
    """
    Find the stack frame of the caller so that we can note the source
    file name, line number and function name.
    """
    f = currentframe()
    #On some versions of IronPython, currentframe() returns None if
    #IronPython isn't run with -X:Frames.
    if f is not None:
        f = f.f_back
    rv = "(unknown file)", 0, "(unknown function)"
    while hasattr(f, "f_code"):
        co = f.f_code
        filename = os.path.normcase(co.co_filename)
        if filename == _srcfile:
            f = f.f_back
            continue
        rv = (co.co_filename, f.f_lineno, co.co_name)
        break
    return rv
def _log(self, level, msg, args, exc_info=None, extra=None):
    """
    Low-level logging routine which creates a LogRecord and then calls
    all the handlers of this logger to handle the record.
    """
    if _srcfile:
        #IronPython doesn't track Python frames, so findCaller throws an
        #exception on some versions of IronPython. We trap it here so that
        #IronPython can use logging.
        try:
            fn, lno, func = self.findCaller()
        except ValueError:
            fn, lno, func = "(unknown file)", 0, "(unknown function)"
    else:
        fn, lno, func = "(unknown file)", 0, "(unknown function)"
    if exc_info:
        if not isinstance(exc_info, tuple):
            exc_info = sys.exc_info()
    record = self.makeRecord(self.name, level, fn, lno, msg, args, exc_info, func, extra)
    self.handle(record)