# util.py - Utilities for declaring interfaces.

#

# Copyright 2018 Gregory Szorc <gregory.szorc@gmail.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

# zope.interface imposes a run-time cost due to module import overhead and

# bookkeeping for declaring interfaces. So, we use stubs for various

# zope.interface primitives unless instructed otherwise.

from .. import encoding

if encoding.environ.get(b'HGREALINTERFACES'):

    from ..thirdparty.zope import interface as zi

    Attribute = zi.Attribute

    Interface = zi.Interface

    implementer = zi.implementer

else:

    class Attribute:

        def __init__(self, __name__, __doc__=b''):

            pass

    class Interface:

        def __init__(

            self, name, bases=(), attrs=None, __doc__=None, __module__=None

        ):

            pass

    def implementer(*ifaces):

        def wrapper(cls):

            return cls

        return wrapper