requires: re-use vfs.tryread for simplicity
Avoids calling `set` twice or having to re-raise an exception and implements the routine with a single return expression.
# 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