helpers.py 文件源码

def stdchannel_redirected(stdchannel, dest_filename):
    """ A context manager to temporarily redirect stdout or stderr

        :param stdchannel: the channel to redirect
        :type stdchannel: sys.std
        :param dest_filename: the filename to redirect output to
        :type dest_filename: os.devnull

        :return: nothing
        :rtype: None
    """

    try:
        oldstdchannel = os.dup(stdchannel.fileno())
        dest_file = open(dest_filename, 'w')
        os.dup2(dest_file.fileno(), stdchannel.fileno())

        yield
    finally:
        if oldstdchannel is not None:
            os.dup2(oldstdchannel, stdchannel.fileno())
        if dest_file is not None:
            dest_file.close()