import operator
from .compat import PY2
from .compat import PY3
from .compat import string_types
from .compat import with_metaclass
from .utils import identity
class _ProxyMethods(object):
# We use properties to override the values of __module__ and
# __doc__. If we add these in ObjectProxy, the derived class
# __dict__ will still be setup to have string variants of these
# attributes and the rules of descriptors means that they appear to
# take precedence over the properties in the base class. To avoid
# that, we copy the properties into the derived class type itself
# via a meta class. In that way the properties will always take
# precedence.
@property
def __module__(self):
return self.__wrapped__.__module__
@__module__.setter
def __module__(self, value):
self.__wrapped__.__module__ = value
@property
def __doc__(self):
return self.__wrapped__.__doc__
@__doc__.setter
def __doc__(self, value):
self.__wrapped__.__doc__ = value
# We similar use a property for __dict__. We need __dict__ to be
# explicit to ensure that vars() works as expected.
@property
def __dict__(self):
return self.__wrapped__.__dict__
# Need to also propagate the special __weakref__ attribute for case
# where decorating classes which will define this. If do not define
# it and use a function like inspect.getmembers() on a decorator
# class it will fail. This can't be in the derived classes.
@property
def __weakref__(self):
return self.__wrapped__.__weakref__
class _ProxyMetaType(type):
def __new__(cls, name, bases, dictionary):
# Copy our special properties into the class so that they
# always take precedence over attributes of the same name added
# during construction of a derived class. This is to save
# duplicating the implementation for them in all derived classes.
dictionary.update(vars(_ProxyMethods))
return type.__new__(cls, name, bases, dictionary)
class Proxy(with_metaclass(_ProxyMetaType)):
"""
A proxy implementation in pure Python, using slots. You can subclass this to add
local methods or attributes, or enable __dict__.
The most important internals:
* ``__factory__`` is the callback that "materializes" the object we proxy to.
* ``__target__`` will contain the object we proxy to, once it's "materialized".
* ``__wrapped__`` is a property that does either:
* return ``__target__`` if it's set.
* calls ``__factory__``, saves result to ``__target__`` and returns said result.
"""
__slots__ = '__target__', '__factory__'
def __init__(self, factory):
object.__setattr__(self, '__factory__', factory)
@property
def __wrapped__(self, __getattr__=object.__getattribute__, __setattr__=object.__setattr__,
__delattr__=object.__delattr__):
try:
return __getattr__(self, '__target__')
except AttributeError:
try:
factory = __getattr__(self, '__factory__')
except AttributeError:
raise ValueError("Proxy hasn't been initiated: __factory__ is missing.")
target = factory()
__setattr__(self, '__target__', target)
return target
@__wrapped__.deleter
def __wrapped__(self, __delattr__=object.__delattr__):
__delattr__(self, '__target__')
@__wrapped__.setter
def __wrapped__(self, target, __setattr__=object.__setattr__):
__setattr__(self, '__target__', target)
@property
def __name__(self):
return self.__wrapped__.__name__
@__name__.setter
def __name__(self, value):
self.__wrapped__.__name__ = value
@property
def __class__(self):
return self.__wrapped__.__class__
@__class__.setter # noqa: F811
def __class__(self, value): # noqa: F811
self.__wrapped__.__class__ = value
@property
def __annotations__(self):
return self.__wrapped__.__anotations__
@__annotations__.setter
def __annotations__(self, value):
self.__wrapped__.__annotations__ = value
def __dir__(self):
return dir(self.__wrapped__)
def __str__(self):
return str(self.__wrapped__)
if PY3:
def __bytes__(self):
return bytes(self.__wrapped__)
def __repr__(self, __getattr__=object.__getattribute__):
try:
target = __getattr__(self, '__target__')
except AttributeError:
return '<{} at 0x{:x} with factory {!r}>'.format(
type(self).__name__, id(self),
self.__factory__
)
else:
return '<{} at 0x{:x} wrapping {!r} at 0x{:x} with factory {!r}>'.format(
type(self).__name__, id(self),
target, id(target),
self.__factory__
)
def __fspath__(self):
wrapped = self.__wrapped__
if isinstance(wrapped, string_types):
return wrapped
else:
fspath = getattr(wrapped, '__fspath__', None)
if fspath is None:
return wrapped
else:
return fspath()
def __reversed__(self):
return reversed(self.__wrapped__)
if PY3:
def __round__(self):
return round(self.__wrapped__)
def __lt__(self, other):
return self.__wrapped__ < other
def __le__(self, other):
return self.__wrapped__ <= other
def __eq__(self, other):
return self.__wrapped__ == other
def __ne__(self, other):
return self.__wrapped__ != other
def __gt__(self, other):
return self.__wrapped__ > other
def __ge__(self, other):
return self.__wrapped__ >= other
def __hash__(self):
return hash(self.__wrapped__)
def __nonzero__(self):
return bool(self.__wrapped__)
def __bool__(self):
return bool(self.__wrapped__)
def __setattr__(self, name, value, __setattr__=object.__setattr__):
if hasattr(type(self), name):
__setattr__(self, name, value)
else:
setattr(self.__wrapped__, name, value)
def __getattr__(self, name):
if name in ('__wrapped__', '__factory__'):
raise AttributeError(name)
else:
return getattr(self.__wrapped__, name)
def __delattr__(self, name, __delattr__=object.__delattr__):
if hasattr(type(self), name):
__delattr__(self, name)
else:
delattr(self.__wrapped__, name)
def __add__(self, other):
return self.__wrapped__ + other
def __sub__(self, other):
return self.__wrapped__ - other
def __mul__(self, other):
return self.__wrapped__ * other
def __div__(self, other):
return operator.div(self.__wrapped__, other)
def __truediv__(self, other):
return operator.truediv(self.__wrapped__, other)
def __floordiv__(self, other):
return self.__wrapped__ // other
def __mod__(self, other):
return self.__wrapped__ % other
def __divmod__(self, other):
return divmod(self.__wrapped__, other)
def __pow__(self, other, *args):
return pow(self.__wrapped__, other, *args)
def __lshift__(self, other):
return self.__wrapped__ << other
def __rshift__(self, other):
return self.__wrapped__ >> other
def __and__(self, other):
return self.__wrapped__ & other
def __xor__(self, other):
return self.__wrapped__ ^ other
def __or__(self, other):
return self.__wrapped__ | other
def __radd__(self, other):
return other + self.__wrapped__
def __rsub__(self, other):
return other - self.__wrapped__
def __rmul__(self, other):
return other * self.__wrapped__
def __rdiv__(self, other):
return operator.div(other, self.__wrapped__)
def __rtruediv__(self, other):
return operator.truediv(other, self.__wrapped__)
def __rfloordiv__(self, other):
return other // self.__wrapped__
def __rmod__(self, other):
return other % self.__wrapped__
def __rdivmod__(self, other):
return divmod(other, self.__wrapped__)
def __rpow__(self, other, *args):
return pow(other, self.__wrapped__, *args)
def __rlshift__(self, other):
return other << self.__wrapped__
def __rrshift__(self, other):
return other >> self.__wrapped__
def __rand__(self, other):
return other & self.__wrapped__
def __rxor__(self, other):
return other ^ self.__wrapped__
def __ror__(self, other):
return other | self.__wrapped__
def __iadd__(self, other):
self.__wrapped__ += other
return self
def __isub__(self, other):
self.__wrapped__ -= other
return self
def __imul__(self, other):
self.__wrapped__ *= other
return self
def __idiv__(self, other):
self.__wrapped__ = operator.idiv(self.__wrapped__, other)
return self
def __itruediv__(self, other):
self.__wrapped__ = operator.itruediv(self.__wrapped__, other)
return self
def __ifloordiv__(self, other):
self.__wrapped__ //= other
return self
def __imod__(self, other):
self.__wrapped__ %= other
return self
def __ipow__(self, other):
self.__wrapped__ **= other
return self
def __ilshift__(self, other):
self.__wrapped__ <<= other
return self
def __irshift__(self, other):
self.__wrapped__ >>= other
return self
def __iand__(self, other):
self.__wrapped__ &= other
return self
def __ixor__(self, other):
self.__wrapped__ ^= other
return self
def __ior__(self, other):
self.__wrapped__ |= other
return self
def __neg__(self):
return -self.__wrapped__
def __pos__(self):
return +self.__wrapped__
def __abs__(self):
return abs(self.__wrapped__)
def __invert__(self):
return ~self.__wrapped__
def __int__(self):
return int(self.__wrapped__)
if PY2:
def __long__(self):
return long(self.__wrapped__) # noqa
def __float__(self):
return float(self.__wrapped__)
def __oct__(self):
return oct(self.__wrapped__)
def __hex__(self):
return hex(self.__wrapped__)
def __index__(self):
return operator.index(self.__wrapped__)
def __len__(self):
return len(self.__wrapped__)
def __contains__(self, value):
return value in self.__wrapped__
def __getitem__(self, key):
return self.__wrapped__[key]
def __setitem__(self, key, value):
self.__wrapped__[key] = value
def __delitem__(self, key):
del self.__wrapped__[key]
def __getslice__(self, i, j):
return self.__wrapped__[i:j]
def __setslice__(self, i, j, value):
self.__wrapped__[i:j] = value
def __delslice__(self, i, j):
del self.__wrapped__[i:j]
def __enter__(self):
return self.__wrapped__.__enter__()
def __exit__(self, *args, **kwargs):
return self.__wrapped__.__exit__(*args, **kwargs)
def __iter__(self):
return iter(self.__wrapped__)
def __call__(self, *args, **kwargs):
return self.__wrapped__(*args, **kwargs)
def __reduce__(self):
return identity, (self.__wrapped__,)
def __reduce_ex__(self, protocol):
return identity, (self.__wrapped__,)
