def challenge_meta(attributes):
"""
Returns a metaclass that will introduce the given attributes into the class
namespace.
Args:
attributes: The dictionary of attributes
Returns:
The metaclass described above
"""
class ChallengeMeta(ABCMeta):
def __new__(cls, name, bases, attr):
attrs = dict(attr)
attrs.update(attributes)
return super().__new__(cls, name, bases, attrs)
return ChallengeMeta
python类ABCMeta()的实例源码
def setUpClass(cls):
FinalABCMeta = final_meta_factory(ABCMeta)
class ABCWithFinal(with_metaclass(FinalABCMeta, object)):
a = final('ABCWithFinal: a')
b = 'ABCWithFinal: b'
@final
def f(self):
return 'ABCWithFinal: f'
def g(self):
return 'ABCWithFinal: g'
@abstractmethod
def h(self):
raise NotImplementedError('h')
cls.class_ = ABCWithFinal
def mk_awaitable():
from abc import abstractmethod, ABCMeta
@abstractmethod
def __await__(self):
yield
@classmethod
def __subclasshook__(cls, C):
if cls is Awaitable:
for B in C.__mro__:
if '__await__' in B.__dict__:
if B.__dict__['__await__']:
return True
break
return NotImplemented
# calling metaclass directly as syntax differs in Py2/Py3
Awaitable = ABCMeta('Awaitable', (), {
'__slots__': (),
'__await__': __await__,
'__subclasshook__': __subclasshook__,
})
return Awaitable
def mk_awaitable():
from abc import abstractmethod, ABCMeta
@abstractmethod
def __await__(self):
yield
@classmethod
def __subclasshook__(cls, C):
if cls is Awaitable:
for B in C.__mro__:
if '__await__' in B.__dict__:
if B.__dict__['__await__']:
return True
break
return NotImplemented
# calling metaclass directly as syntax differs in Py2/Py3
Awaitable = ABCMeta('Awaitable', (), {
'__slots__': (),
'__await__': __await__,
'__subclasshook__': __subclasshook__,
})
return Awaitable
def mk_awaitable():
from abc import abstractmethod, ABCMeta
@abstractmethod
def __await__(self):
yield
@classmethod
def __subclasshook__(cls, C):
if cls is Awaitable:
for B in C.__mro__:
if '__await__' in B.__dict__:
if B.__dict__['__await__']:
return True
break
return NotImplemented
# calling metaclass directly as syntax differs in Py2/Py3
Awaitable = ABCMeta('Awaitable', (), {
'__slots__': (),
'__await__': __await__,
'__subclasshook__': __subclasshook__,
})
return Awaitable
def challenge_meta(attributes):
"""
Returns a metaclass that will introduce the given attributes into the class
namespace.
Args:
attributes: The dictionary of attributes
Returns:
The metaclass described above
"""
class ChallengeMeta(ABCMeta):
def __new__(cls, name, bases, attr):
attrs = dict(attr)
attrs.update(attributes)
return super().__new__(cls, name, bases, attrs)
return ChallengeMeta
def generate_immutable_abc(supercls, mutable_subclass):
class ABCImmutableMeta(ABCMeta):
def __subclasscheck__(cls, subclass):
if not issubclass(subclass, supercls):
return False
return not issubclass(subclass, mutable_subclass)
class ABCImmutable(with_metaclass(ABCImmutableMeta, object)):
pass
# dirty hack to assert issubclass(ABCImmutable, supercls).
supercls._abc_cache.add(ABCImmutable)
return ABCImmutable
def __new__(mcs, name, bases, dikt):
fields = {}
for base in bases:
fields.update(getattr(base, '_fields', {}))
# Do not reorder, this class might override fields from base classes!
for key, value in tuple(six.iteritems(dikt)):
# not six.iterkeys() (in-place edit!)
if isinstance(value, Field):
fields[key] = dikt.pop(key)
dikt['_orig_slots'] = dikt.get('__slots__', ())
dikt['__slots__'] = tuple(
list(dikt['_orig_slots']) + list(six.iterkeys(fields)))
dikt['_fields'] = fields
return abc.ABCMeta.__new__(mcs, name, bases, dikt)
def setUpClass(cls):
FinalABCMeta = compose_types(FinalMeta, ABCMeta)
class ABCWithFinal(with_metaclass(FinalABCMeta, object)):
a = final('ABCWithFinal: a')
b = 'ABCWithFinal: b'
@final
def f(self):
return 'ABCWithFinal: f'
def g(self):
return 'ABCWithFinal: g'
@abstractmethod
def h(self):
raise NotImplementedError('h')
cls.class_ = ABCWithFinal
def test_abstractclassmethod_basics(self):
@abc.abstractclassmethod
def foo(cls): pass
self.assertTrue(foo.__isabstractmethod__)
@classmethod
def bar(cls): pass
self.assertFalse(hasattr(bar, "__isabstractmethod__"))
class C(metaclass=abc.ABCMeta):
@abc.abstractclassmethod
def foo(cls): return cls.__name__
self.assertRaises(TypeError, C)
class D(C):
@classmethod
def foo(cls): return super().foo()
self.assertEqual(D.foo(), 'D')
self.assertEqual(D().foo(), 'D')
def test_abstractstaticmethod_basics(self):
@abc.abstractstaticmethod
def foo(): pass
self.assertTrue(foo.__isabstractmethod__)
@staticmethod
def bar(): pass
self.assertFalse(hasattr(bar, "__isabstractmethod__"))
class C(metaclass=abc.ABCMeta):
@abc.abstractstaticmethod
def foo(): return 3
self.assertRaises(TypeError, C)
class D(C):
@staticmethod
def foo(): return 4
self.assertEqual(D.foo(), 4)
self.assertEqual(D().foo(), 4)
def test_registration_builtins(self):
class A(metaclass=abc.ABCMeta):
pass
A.register(int)
self.assertIsInstance(42, A)
self.assertIsInstance(42, (A,))
self.assertTrue(issubclass(int, A))
self.assertTrue(issubclass(int, (A,)))
class B(A):
pass
B.register(str)
class C(str): pass
self.assertIsInstance("", A)
self.assertIsInstance("", (A,))
self.assertTrue(issubclass(str, A))
self.assertTrue(issubclass(str, (A,)))
self.assertTrue(issubclass(C, A))
self.assertTrue(issubclass(C, (A,)))
def test_registration_edge_cases(self):
class A(metaclass=abc.ABCMeta):
pass
A.register(A) # should pass silently
class A1(A):
pass
self.assertRaises(RuntimeError, A1.register, A) # cycles not allowed
class B(object):
pass
A1.register(B) # ok
A1.register(B) # should pass silently
class C(A):
pass
A.register(C) # should pass silently
self.assertRaises(RuntimeError, C.register, A) # cycles not allowed
C.register(B) # ok
def test_slots_descriptor(self):
# Issue2115: slot descriptors did not correctly check
# the type of the given object
import abc
class MyABC(metaclass=abc.ABCMeta):
__slots__ = "a"
class Unrelated(object):
pass
MyABC.register(Unrelated)
u = Unrelated()
self.assertIsInstance(u, MyABC)
# This used to crash
self.assertRaises(TypeError, MyABC.a.__set__, u, 3)
def test_isabstract(self):
from abc import ABCMeta, abstractmethod
class AbstractClassExample(metaclass=ABCMeta):
@abstractmethod
def foo(self):
pass
class ClassExample(AbstractClassExample):
def foo(self):
pass
a = ClassExample()
# Test general behaviour.
self.assertTrue(inspect.isabstract(AbstractClassExample))
self.assertFalse(inspect.isabstract(ClassExample))
self.assertFalse(inspect.isabstract(a))
self.assertFalse(inspect.isabstract(int))
self.assertFalse(inspect.isabstract(5))
def __new__(mcs, name, bases, dikt):
fields = {}
for base in bases:
fields.update(getattr(base, '_fields', {}))
# Do not reorder, this class might override fields from base classes!
for key, value in tuple(six.iteritems(dikt)):
# not six.iterkeys() (in-place edit!)
if isinstance(value, Field):
fields[key] = dikt.pop(key)
dikt['_orig_slots'] = dikt.get('__slots__', ())
dikt['__slots__'] = tuple(
list(dikt['_orig_slots']) + list(six.iterkeys(fields)))
dikt['_fields'] = fields
return abc.ABCMeta.__new__(mcs, name, bases, dikt)
def test_registration_basics(self):
class A:
__metaclass__ = abc.ABCMeta
class B(object):
pass
b = B()
self.assertFalse(issubclass(B, A))
self.assertFalse(issubclass(B, (A,)))
self.assertNotIsInstance(b, A)
self.assertNotIsInstance(b, (A,))
A.register(B)
self.assertTrue(issubclass(B, A))
self.assertTrue(issubclass(B, (A,)))
self.assertIsInstance(b, A)
self.assertIsInstance(b, (A,))
class C(B):
pass
c = C()
self.assertTrue(issubclass(C, A))
self.assertTrue(issubclass(C, (A,)))
self.assertIsInstance(c, A)
self.assertIsInstance(c, (A,))
def test_registration_edge_cases(self):
class A:
__metaclass__ = abc.ABCMeta
A.register(A) # should pass silently
class A1(A):
pass
self.assertRaises(RuntimeError, A1.register, A) # cycles not allowed
class B(object):
pass
A1.register(B) # ok
A1.register(B) # should pass silently
class C(A):
pass
A.register(C) # should pass silently
self.assertRaises(RuntimeError, C.register, A) # cycles not allowed
C.register(B) # ok
def test_slots_descriptor(self):
# Issue2115: slot descriptors did not correctly check
# the type of the given object
import abc
class MyABC:
__metaclass__ = abc.ABCMeta
__slots__ = "a"
class Unrelated(object):
pass
MyABC.register(Unrelated)
u = Unrelated()
self.assertIsInstance(u, MyABC)
# This used to crash
self.assertRaises(TypeError, MyABC.a.__set__, u, 3)
def test_registration_basics(self):
class A:
__metaclass__ = abc.ABCMeta
class B(object):
pass
b = B()
self.assertFalse(issubclass(B, A))
self.assertFalse(issubclass(B, (A,)))
self.assertNotIsInstance(b, A)
self.assertNotIsInstance(b, (A,))
A.register(B)
self.assertTrue(issubclass(B, A))
self.assertTrue(issubclass(B, (A,)))
self.assertIsInstance(b, A)
self.assertIsInstance(b, (A,))
class C(B):
pass
c = C()
self.assertTrue(issubclass(C, A))
self.assertTrue(issubclass(C, (A,)))
self.assertIsInstance(c, A)
self.assertIsInstance(c, (A,))
def test_registration_edge_cases(self):
class A:
__metaclass__ = abc.ABCMeta
A.register(A) # should pass silently
class A1(A):
pass
self.assertRaises(RuntimeError, A1.register, A) # cycles not allowed
class B(object):
pass
A1.register(B) # ok
A1.register(B) # should pass silently
class C(A):
pass
A.register(C) # should pass silently
self.assertRaises(RuntimeError, C.register, A) # cycles not allowed
C.register(B) # ok
def test_slots_descriptor(self):
# Issue2115: slot descriptors did not correctly check
# the type of the given object
import abc
class MyABC:
__metaclass__ = abc.ABCMeta
__slots__ = "a"
class Unrelated(object):
pass
MyABC.register(Unrelated)
u = Unrelated()
self.assertIsInstance(u, MyABC)
# This used to crash
self.assertRaises(TypeError, MyABC.a.__set__, u, 3)
backports_abc.py 文件源码
项目：My-Web-Server-Framework-With-Python2.7
作者: syjsu
项目源码
文件源码
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def mk_awaitable():
from abc import abstractmethod, ABCMeta
@abstractmethod
def __await__(self):
yield
@classmethod
def __subclasshook__(cls, C):
if cls is Awaitable:
for B in C.__mro__:
if '__await__' in B.__dict__:
if B.__dict__['__await__']:
return True
break
return NotImplemented
# calling metaclass directly as syntax differs in Py2/Py3
Awaitable = ABCMeta('Awaitable', (), {
'__slots__': (),
'__await__': __await__,
'__subclasshook__': __subclasshook__,
})
return Awaitable
def test_abstractproperty_basics(self):
@abc.abstractproperty
def foo(self): pass
self.assertTrue(foo.__isabstractmethod__)
def bar(self): pass
self.assertFalse(hasattr(bar, "__isabstractmethod__"))
class C(metaclass=abc.ABCMeta):
@abc.abstractproperty
def foo(self): return 3
self.assertRaises(TypeError, C)
class D(C):
@property
def foo(self): return super().foo
self.assertEqual(D().foo, 3)
self.assertFalse(getattr(D.foo, "__isabstractmethod__", False))
def test_abstractclassmethod_basics(self):
@abc.abstractclassmethod
def foo(cls): pass
self.assertTrue(foo.__isabstractmethod__)
@classmethod
def bar(cls): pass
self.assertFalse(getattr(bar, "__isabstractmethod__", False))
class C(metaclass=abc.ABCMeta):
@abc.abstractclassmethod
def foo(cls): return cls.__name__
self.assertRaises(TypeError, C)
class D(C):
@classmethod
def foo(cls): return super().foo()
self.assertEqual(D.foo(), 'D')
self.assertEqual(D().foo(), 'D')
def test_abstractproperty_basics(self):
@property
@abc.abstractmethod
def foo(self): pass
self.assertTrue(foo.__isabstractmethod__)
def bar(self): pass
self.assertFalse(getattr(bar, "__isabstractmethod__", False))
class C(metaclass=abc.ABCMeta):
@property
@abc.abstractmethod
def foo(self): return 3
self.assertRaises(TypeError, C)
class D(C):
@C.foo.getter
def foo(self): return super().foo
self.assertEqual(D().foo, 3)
def test_abstractclassmethod_basics(self):
@classmethod
@abc.abstractmethod
def foo(cls): pass
self.assertTrue(foo.__isabstractmethod__)
@classmethod
def bar(cls): pass
self.assertFalse(getattr(bar, "__isabstractmethod__", False))
class C(metaclass=abc.ABCMeta):
@classmethod
@abc.abstractmethod
def foo(cls): return cls.__name__
self.assertRaises(TypeError, C)
class D(C):
@classmethod
def foo(cls): return super().foo()
self.assertEqual(D.foo(), 'D')
self.assertEqual(D().foo(), 'D')
def test_abstractstaticmethod_basics(self):
@staticmethod
@abc.abstractmethod
def foo(): pass
self.assertTrue(foo.__isabstractmethod__)
@staticmethod
def bar(): pass
self.assertFalse(getattr(bar, "__isabstractmethod__", False))
class C(metaclass=abc.ABCMeta):
@staticmethod
@abc.abstractmethod
def foo(): return 3
self.assertRaises(TypeError, C)
class D(C):
@staticmethod
def foo(): return 4
self.assertEqual(D.foo(), 4)
self.assertEqual(D().foo(), 4)
def test_registration_basics(self):
class A(metaclass=abc.ABCMeta):
pass
class B(object):
pass
b = B()
self.assertFalse(issubclass(B, A))
self.assertFalse(issubclass(B, (A,)))
self.assertNotIsInstance(b, A)
self.assertNotIsInstance(b, (A,))
B1 = A.register(B)
self.assertTrue(issubclass(B, A))
self.assertTrue(issubclass(B, (A,)))
self.assertIsInstance(b, A)
self.assertIsInstance(b, (A,))
self.assertIs(B1, B)
class C(B):
pass
c = C()
self.assertTrue(issubclass(C, A))
self.assertTrue(issubclass(C, (A,)))
self.assertIsInstance(c, A)
self.assertIsInstance(c, (A,))
def test_register_as_class_deco(self):
class A(metaclass=abc.ABCMeta):
pass
@A.register
class B(object):
pass
b = B()
self.assertTrue(issubclass(B, A))
self.assertTrue(issubclass(B, (A,)))
self.assertIsInstance(b, A)
self.assertIsInstance(b, (A,))
@A.register
class C(B):
pass
c = C()
self.assertTrue(issubclass(C, A))
self.assertTrue(issubclass(C, (A,)))
self.assertIsInstance(c, A)
self.assertIsInstance(c, (A,))
self.assertIs(C, A.register(C))
