utils.py 文件源码

def _get_hash_object(hash_algo_name):
    """Create a hash object based on given algorithm.

    :param hash_algo_name: name of the hashing algorithm.
    :raises: InvalidInputError, on unsupported or invalid input.
    :returns: a hash object based on the given named algorithm.
    """
    algorithms = (hashlib.algorithms_guaranteed if six.PY3
                  else hashlib.algorithms)
    if hash_algo_name not in algorithms:
        msg = ("Unsupported/Invalid hash name '%s' provided."
               % hash_algo_name)
        raise exception.InvalidInputError(msg)

    return getattr(hashlib, hash_algo_name)()