orbit-oss/flask
4
4
Fork 2
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Reimplement function with_metaclass()

Browse source
This commit is contained in:
Mathias J. Hennig 2015-07-22 23:35:13 +02:00
parent ac12e362c4
commit c8f19f0afc
1 changed files with 4 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

16
flask/_compat.py
View file

@ -56,21 +56,13 @@ else:
def with_metaclass(meta, *bases):
# This requires a bit of explanation: the basic idea is to make a
# dummy metaclass for one level of class instantiation that replaces
# itself with the actual metaclass. Because of internal type checks
# we also need to make sure that we downgrade the custom metaclass
# for one level to something closer to type (that's why __call__ and
# __init__ comes back from type etc.).
# itself with the actual metaclass.
#
# This has the advantage over six.with_metaclass in that it does not
# introduce dummy classes into the final MRO.
class metaclass(meta):
__call__ = type.__call__
__init__ = type.__init__
def __new__(cls, name, this_bases, d):
if this_bases is None:
return type.__new__(cls, name, (), d)
return meta(name, bases, d)
return metaclass('temporary_class', None, {})
constructor = lambda c, name, b, dct: meta(name, bases, dct)
metaclass = type('with_metaclass', (type,), {'__new__': constructor})
return type.__new__(metaclass, 'temporary_class', (object,), {})
# Certain versions of pypy have a bug where clearing the exception stack