mirror of https://github.com/morpheus65535/bazarr
76 lines
2.4 KiB
Python
76 lines
2.4 KiB
Python
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
|
|
|
|
# This implementation of the immutable decorator requires python >=
|
|
# 3.7, and is significantly more storage efficient when making classes
|
|
# with slots immutable. It's also faster.
|
|
|
|
import contextvars
|
|
import inspect
|
|
|
|
|
|
_in__init__ = contextvars.ContextVar('_immutable_in__init__', default=False)
|
|
|
|
|
|
class _Immutable:
|
|
"""Immutable mixin class"""
|
|
|
|
# We set slots to the empty list to say "we don't have any attributes".
|
|
# We do this so that if we're mixed in with a class with __slots__, we
|
|
# don't cause a __dict__ to be added which would waste space.
|
|
|
|
__slots__ = ()
|
|
|
|
def __setattr__(self, name, value):
|
|
if _in__init__.get() is not self:
|
|
raise TypeError("object doesn't support attribute assignment")
|
|
else:
|
|
super().__setattr__(name, value)
|
|
|
|
def __delattr__(self, name):
|
|
if _in__init__.get() is not self:
|
|
raise TypeError("object doesn't support attribute assignment")
|
|
else:
|
|
super().__delattr__(name)
|
|
|
|
|
|
def _immutable_init(f):
|
|
def nf(*args, **kwargs):
|
|
previous = _in__init__.set(args[0])
|
|
try:
|
|
# call the actual __init__
|
|
f(*args, **kwargs)
|
|
finally:
|
|
_in__init__.reset(previous)
|
|
nf.__signature__ = inspect.signature(f)
|
|
return nf
|
|
|
|
|
|
def immutable(cls):
|
|
if _Immutable in cls.__mro__:
|
|
# Some ancestor already has the mixin, so just make sure we keep
|
|
# following the __init__ protocol.
|
|
cls.__init__ = _immutable_init(cls.__init__)
|
|
if hasattr(cls, '__setstate__'):
|
|
cls.__setstate__ = _immutable_init(cls.__setstate__)
|
|
ncls = cls
|
|
else:
|
|
# Mixin the Immutable class and follow the __init__ protocol.
|
|
class ncls(_Immutable, cls):
|
|
# We have to do the __slots__ declaration here too!
|
|
__slots__ = ()
|
|
|
|
@_immutable_init
|
|
def __init__(self, *args, **kwargs):
|
|
super().__init__(*args, **kwargs)
|
|
|
|
if hasattr(cls, '__setstate__'):
|
|
@_immutable_init
|
|
def __setstate__(self, *args, **kwargs):
|
|
super().__setstate__(*args, **kwargs)
|
|
|
|
# make ncls have the same name and module as cls
|
|
ncls.__name__ = cls.__name__
|
|
ncls.__qualname__ = cls.__qualname__
|
|
ncls.__module__ = cls.__module__
|
|
return ncls
|