annotate mercurial/thirdparty/zope/interface/_compat.py @ 37176:943d77fc07a3

thirdparty: vendor zope.interface 4.4.3

I've been trying to formalize interfaces for various components
of Mercurial. So far, we've been using the "abc" package. This
package is "good enough" for a lot of tasks. But it quickly
falls over. For example, if you declare an @abc.abstractproperty,
you must implement that attribute with a @property or the class
compile time checking performed by abc will complain. This often
forces you to implement dumb @property wrappers to return a
_ prefixed attribute of the sane name. That's ugly.

I've also wanted to implement automated checking that classes
conform to various interfaces and don't expose other "public"
attributes.

After doing a bit of research and asking around, the general
consensus seems to be that zope.interface is the best package for
doing interface-based programming in Python. It has built-in
support for verifying classes and objects conform to interfaces.
It allows an interface's properties to be defined during __init__.
There's even an "adapter registry" that allow you to register
interfaces and look up which classes implement them. That could
potentially be useful for places where our custom registry.py
modules currently facilitates central registrations, but at a
type level. Imagine extensions providing alternate implementations
of things like the local repository interface to allow opening
repositories with custom requirements.

Anyway, this commit vendors zope.interface 4.4.3. The contents of
the source tarball have been copied into mercurial/thirdparty/zope/
without modifications.

Test modules have been removed because they are not interesting
to us.

The LICENSE.txt file has been copied so it lives next to the
source.

The Python modules don't use relative imports. zope/__init__.py
defines a namespace package. So we'll need to modify the source
code before this package is usable inside Mercurial. This will
be done in subsequent commits.

# no-check-commit for various style failures

Differential Revision: https://phab.mercurial-scm.org/D2928

##############################################################################
#
# Copyright (c) 2006 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Basic components support
"""
import sys
import types

if sys.version_info[0] < 3:

    def _normalize_name(name):
        if isinstance(name, basestring):
            return unicode(name)
        raise TypeError("name must be a regular or unicode string")

    CLASS_TYPES = (type, types.ClassType)
    STRING_TYPES = (basestring,)

    _BUILTINS = '__builtin__'

    PYTHON3 = False
    PYTHON2 = True

else:

    def _normalize_name(name):
        if isinstance(name, bytes):
            name = str(name, 'ascii')
        if isinstance(name, str):
            return name
        raise TypeError("name must be a string or ASCII-only bytes")

    CLASS_TYPES = (type,)
    STRING_TYPES = (str,)

    _BUILTINS = 'builtins'

    PYTHON3 = True
    PYTHON2 = False

def _skip_under_py3k(test_method):
    import unittest
    return unittest.skipIf(sys.version_info[0] >= 3, "Only on Python 2")(test_method)


def _skip_under_py2(test_method):
    import unittest
    return unittest.skipIf(sys.version_info[0] < 3, "Only on Python 3")(test_method)