mirror of
https://github.com/python/cpython.git
synced 2025-11-04 03:44:55 +00:00
129 lines
4.4 KiB
Python
129 lines
4.4 KiB
Python
# Copyright 2007 Google, Inc. All Rights Reserved.
|
|
# Licensed to PSF under a Contributor Agreement.
|
|
|
|
"""Abstract Base Classes (ABCs) according to PEP 3119."""
|
|
|
|
|
|
def abstractmethod(funcobj):
|
|
"""A decorator indicating abstract methods.
|
|
|
|
Requires that the metaclass is ABCMeta or derived from it. A
|
|
class that has a metaclass derived from ABCMeta cannot be
|
|
instantiated unless all of its abstract methods are overridden.
|
|
The abstract methods can be called using any of the normal
|
|
'super' call mechanisms. abstractmethod() may be used to declare
|
|
abstract methods for properties and descriptors.
|
|
|
|
Usage:
|
|
|
|
class C(metaclass=ABCMeta):
|
|
@abstractmethod
|
|
def my_abstract_method(self, ...):
|
|
...
|
|
"""
|
|
funcobj.__isabstractmethod__ = True
|
|
return funcobj
|
|
|
|
|
|
class abstractclassmethod(classmethod):
|
|
"""A decorator indicating abstract classmethods.
|
|
|
|
Deprecated, use 'classmethod' with 'abstractmethod' instead.
|
|
"""
|
|
|
|
__isabstractmethod__ = True
|
|
|
|
def __init__(self, callable):
|
|
callable.__isabstractmethod__ = True
|
|
super().__init__(callable)
|
|
|
|
|
|
class abstractstaticmethod(staticmethod):
|
|
"""A decorator indicating abstract staticmethods.
|
|
|
|
Deprecated, use 'staticmethod' with 'abstractmethod' instead.
|
|
"""
|
|
|
|
__isabstractmethod__ = True
|
|
|
|
def __init__(self, callable):
|
|
callable.__isabstractmethod__ = True
|
|
super().__init__(callable)
|
|
|
|
|
|
class abstractproperty(property):
|
|
"""A decorator indicating abstract properties.
|
|
|
|
Deprecated, use 'property' with 'abstractmethod' instead.
|
|
"""
|
|
|
|
__isabstractmethod__ = True
|
|
|
|
|
|
try:
|
|
from _abc import (get_cache_token, _abc_init, _abc_register,
|
|
_abc_instancecheck, _abc_subclasscheck, _get_dump,
|
|
_reset_registry, _reset_caches)
|
|
except ImportError:
|
|
from _py_abc import ABCMeta, get_cache_token
|
|
ABCMeta.__module__ = 'abc'
|
|
else:
|
|
class ABCMeta(type):
|
|
"""Metaclass for defining Abstract Base Classes (ABCs).
|
|
|
|
Use this metaclass to create an ABC. An ABC can be subclassed
|
|
directly, and then acts as a mix-in class. You can also register
|
|
unrelated concrete classes (even built-in classes) and unrelated
|
|
ABCs as 'virtual subclasses' -- these and their descendants will
|
|
be considered subclasses of the registering ABC by the built-in
|
|
issubclass() function, but the registering ABC won't show up in
|
|
their MRO (Method Resolution Order) nor will method
|
|
implementations defined by the registering ABC be callable (not
|
|
even via super()).
|
|
"""
|
|
def __new__(mcls, name, bases, namespace, **kwargs):
|
|
cls = super().__new__(mcls, name, bases, namespace, **kwargs)
|
|
_abc_init(cls)
|
|
return cls
|
|
|
|
def register(cls, subclass):
|
|
"""Register a virtual subclass of an ABC.
|
|
|
|
Returns the subclass, to allow usage as a class decorator.
|
|
"""
|
|
return _abc_register(cls, subclass)
|
|
|
|
def __instancecheck__(cls, instance):
|
|
"""Override for isinstance(instance, cls)."""
|
|
return _abc_instancecheck(cls, instance)
|
|
|
|
def __subclasscheck__(cls, subclass):
|
|
"""Override for issubclass(subclass, cls)."""
|
|
return _abc_subclasscheck(cls, subclass)
|
|
|
|
def _dump_registry(cls, file=None):
|
|
"""Debug helper to print the ABC registry."""
|
|
print(f"Class: {cls.__module__}.{cls.__qualname__}", file=file)
|
|
print(f"Inv. counter: {get_cache_token()}", file=file)
|
|
(_abc_registry, _abc_cache, _abc_negative_cache,
|
|
_abc_negative_cache_version) = _get_dump(cls)
|
|
print(f"_abc_registry: {_abc_registry!r}", file=file)
|
|
print(f"_abc_cache: {_abc_cache!r}", file=file)
|
|
print(f"_abc_negative_cache: {_abc_negative_cache!r}", file=file)
|
|
print(f"_abc_negative_cache_version: {_abc_negative_cache_version!r}",
|
|
file=file)
|
|
|
|
def _abc_registry_clear(cls):
|
|
"""Clear the registry (for debugging or testing)."""
|
|
_reset_registry(cls)
|
|
|
|
def _abc_caches_clear(cls):
|
|
"""Clear the caches (for debugging or testing)."""
|
|
_reset_caches(cls)
|
|
|
|
|
|
class ABC(metaclass=ABCMeta):
|
|
"""Helper class that provides a standard way to create an ABC using
|
|
inheritance.
|
|
"""
|
|
__slots__ = ()
|