def proxied_attribute_factory(descriptor):
"""Create an InstrumentedAttribute / user descriptor hybrid.
Returns a new InstrumentedAttribute type that delegates descriptor
behavior and getattr() to the given descriptor.
"""
class ProxyImpl(object):
accepts_scalar_loader = False
def __init__(self, key):
self.key = key
class Proxy(InstrumentedAttribute):
"""A combination of InsturmentedAttribute and a regular descriptor."""
def __init__(self, key, descriptor, comparator):
self.key = key
# maintain ProxiedAttribute.user_prop compatability.
self.descriptor = self.user_prop = descriptor
self._comparator = comparator
self.impl = ProxyImpl(key)
def comparator(self):
if callable(self._comparator):
self._comparator = self._comparator()
return self._comparator
comparator = property(comparator)
def __get__(self, instance, owner):
"""Delegate __get__ to the original descriptor."""
if instance is None:
descriptor.__get__(instance, owner)
return self
return descriptor.__get__(instance, owner)
def __set__(self, instance, value):
"""Delegate __set__ to the original descriptor."""
return descriptor.__set__(instance, value)
def __delete__(self, instance):
"""Delegate __delete__ to the original descriptor."""
return descriptor.__delete__(instance)
def __getattr__(self, attribute):
"""Delegate __getattr__ to the original descriptor."""
return getattr(descriptor, attribute)
Proxy.__name__ = type(descriptor).__name__ + 'Proxy'
util.monkeypatch_proxied_specials(Proxy,
type(descriptor),
name='descriptor',
from_instance=descriptor)
return Proxy
def proxied_attribute_factory(descriptor):
"""Create an InstrumentedAttribute / user descriptor hybrid.
Returns a new InstrumentedAttribute type that delegates descriptor
behavior and getattr() to the given descriptor.
"""
class ProxyImpl(object):
accepts_scalar_loader = False
def __init__(self, key):
self.key = key
class Proxy(InstrumentedAttribute):
"""A combination of InsturmentedAttribute and a regular descriptor."""
def __init__(self, key, descriptor, comparator):
self.key = key
# maintain ProxiedAttribute.user_prop compatability.
self.descriptor = self.user_prop = descriptor
self._comparator = comparator
self.impl = ProxyImpl(key)
def comparator(self):
if callable(self._comparator):
self._comparator = self._comparator()
return self._comparator
comparator = property(comparator)
def __get__(self, instance, owner):
"""Delegate __get__ to the original descriptor."""
if instance is None:
descriptor.__get__(instance, owner)
return self
return descriptor.__get__(instance, owner)
def __set__(self, instance, value):
"""Delegate __set__ to the original descriptor."""
return descriptor.__set__(instance, value)
def __delete__(self, instance):
"""Delegate __delete__ to the original descriptor."""
return descriptor.__delete__(instance)
def __getattr__(self, attribute):
"""Delegate __getattr__ to the original descriptor."""
return getattr(descriptor, attribute)
Proxy.__name__ = type(descriptor).__name__ + "Proxy"
util.monkeypatch_proxied_specials(Proxy, type(descriptor), name="descriptor", from_instance=descriptor)
return Proxy
def create_proxied_attribute(descriptor):
"""Create an QueryableAttribute / user descriptor hybrid.
Returns a new QueryableAttribute type that delegates descriptor
behavior and getattr() to the given descriptor.
"""
# TODO: can move this to descriptor_props if the need for this
# function is removed from ext/hybrid.py
class Proxy(QueryableAttribute):
"""Presents the :class:`.QueryableAttribute` interface as a
proxy on top of a Python descriptor / :class:`.PropComparator`
combination.
"""
def __init__(self, class_, key, descriptor, comparator,
adapter=None, doc=None):
self.class_ = class_
self.key = key
self.descriptor = descriptor
self._comparator = comparator
self.adapter = adapter
self.__doc__ = doc
@util.memoized_property
def comparator(self):
if util.callable(self._comparator):
self._comparator = self._comparator()
if self.adapter:
self._comparator = self._comparator.adapted(self.adapter)
return self._comparator
def adapted(self, adapter):
"""Proxy adapted() for the use case of AliasedClass calling adapted."""
return self.__class__(self.class_, self.key, self.descriptor,
self._comparator,
adapter)
def __get__(self, instance, owner):
if instance is None:
return self
else:
return self.descriptor.__get__(instance, owner)
def __str__(self):
return self.key
def __getattr__(self, attribute):
"""Delegate __getattr__ to the original descriptor and/or
comparator."""
try:
return getattr(descriptor, attribute)
except AttributeError:
try:
return getattr(self.comparator, attribute)
except AttributeError:
raise AttributeError(
'Neither %r object nor %r object has an attribute %r' % (
type(descriptor).__name__,
type(self.comparator).__name__,
attribute)
)
Proxy.__name__ = type(descriptor).__name__ + 'Proxy'
util.monkeypatch_proxied_specials(Proxy, type(descriptor),
name='descriptor',
from_instance=descriptor)
return Proxy
def create_proxied_attribute(descriptor):
"""Create an QueryableAttribute / user descriptor hybrid.
Returns a new QueryableAttribute type that delegates descriptor
behavior and getattr() to the given descriptor.
"""
# TODO: can move this to descriptor_props if the need for this
# function is removed from ext/hybrid.py
class Proxy(QueryableAttribute):
"""Presents the :class:`.QueryableAttribute` interface as a
proxy on top of a Python descriptor / :class:`.PropComparator`
combination.
"""
def __init__(self, class_, key, descriptor, comparator,
adapter=None, doc=None):
self.class_ = class_
self.key = key
self.descriptor = descriptor
self._comparator = comparator
self.adapter = adapter
self.__doc__ = doc
@util.memoized_property
def comparator(self):
if util.callable(self._comparator):
self._comparator = self._comparator()
if self.adapter:
self._comparator = self._comparator.adapted(self.adapter)
return self._comparator
def adapted(self, adapter):
"""Proxy adapted() for the use case of AliasedClass calling adapted."""
return self.__class__(self.class_, self.key, self.descriptor,
self._comparator,
adapter)
def __get__(self, instance, owner):
if instance is None:
return self
else:
return self.descriptor.__get__(instance, owner)
def __str__(self):
return self.key
def __getattr__(self, attribute):
"""Delegate __getattr__ to the original descriptor and/or
comparator."""
try:
return getattr(descriptor, attribute)
except AttributeError:
try:
return getattr(self.comparator, attribute)
except AttributeError:
raise AttributeError(
'Neither %r object nor %r object has an attribute %r' % (
type(descriptor).__name__,
type(self.comparator).__name__,
attribute)
)
Proxy.__name__ = type(descriptor).__name__ + 'Proxy'
util.monkeypatch_proxied_specials(Proxy, type(descriptor),
name='descriptor',
from_instance=descriptor)
return Proxy
