8th day of python challenges 111-117

venv/lib/python3.6/site-packages/lazy_object_proxy/simple.py

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+import operator
+
+from .compat import PY2
+from .compat import PY3
+from .compat import with_metaclass
+from .utils import cached_property
+from .utils import identity
+
+
+def make_proxy_method(code):
+    def proxy_wrapper(self, *args):
+        return code(self.__wrapped__, *args)
+
+    return proxy_wrapper
+
+
+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
+
+    # 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))
+        dictionary.pop('__dict__')
+
+        return type.__new__(cls, name, bases, dictionary)
+
+
+class Proxy(with_metaclass(_ProxyMetaType)):
+    __factory__ = None
+
+    def __init__(self, factory):
+        self.__dict__['__factory__'] = factory
+
+    @cached_property
+    def __wrapped__(self):
+        self = self.__dict__
+        if '__factory__' in self:
+            factory = self['__factory__']
+            return factory()
+        else:
+            raise ValueError("Proxy hasn't been initiated: __factory__ is missing.")
+
+    __name__ = property(make_proxy_method(operator.attrgetter('__name__')))
+    __class__ = property(make_proxy_method(operator.attrgetter('__class__')))
+    __annotations__ = property(make_proxy_method(operator.attrgetter('__anotations__')))
+    __dir__ = make_proxy_method(dir)
+    __str__ = make_proxy_method(str)
+
+    if PY3:
+        __bytes__ = make_proxy_method(bytes)
+
+    def __repr__(self, __getattr__=object.__getattribute__):
+        if '__wrapped__' in self.__dict__:
+            return '<{} at 0x{:x} wrapping {!r} at 0x{:x} with factory {!r}>'.format(
+                type(self).__name__, id(self),
+                self.__wrapped__, id(self.__wrapped__),
+                self.__factory__
+            )
+        else:
+            return '<{} at 0x{:x} with factory {!r}>'.format(
+                type(self).__name__, id(self),
+                self.__factory__
+            )
+
+    __reversed__ = make_proxy_method(reversed)
+
+    if PY3:
+        __round__ = make_proxy_method(round)
+
+    __lt__ = make_proxy_method(operator.lt)
+    __le__ = make_proxy_method(operator.le)
+    __eq__ = make_proxy_method(operator.eq)
+    __ne__ = make_proxy_method(operator.ne)
+    __gt__ = make_proxy_method(operator.gt)
+    __ge__ = make_proxy_method(operator.ge)
+    __hash__ = make_proxy_method(hash)
+    __nonzero__ = make_proxy_method(bool)
+    __bool__ = make_proxy_method(bool)
+
+    def __setattr__(self, name, value):
+        if hasattr(type(self), name):
+            self.__dict__[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):
+        if hasattr(type(self), name):
+            del self.__dict__[name]
+        else:
+            delattr(self.__wrapped__, name)
+
+    __add__ = make_proxy_method(operator.add)
+    __sub__ = make_proxy_method(operator.sub)
+    __mul__ = make_proxy_method(operator.mul)
+    __div__ = make_proxy_method(operator.div if PY2 else operator.truediv)
+    __truediv__ = make_proxy_method(operator.truediv)
+    __floordiv__ = make_proxy_method(operator.floordiv)
+    __mod__ = make_proxy_method(operator.mod)
+    __divmod__ = make_proxy_method(divmod)
+    __pow__ = make_proxy_method(pow)
+    __lshift__ = make_proxy_method(operator.lshift)
+    __rshift__ = make_proxy_method(operator.rshift)
+    __and__ = make_proxy_method(operator.and_)
+    __xor__ = make_proxy_method(operator.xor)
+    __or__ = make_proxy_method(operator.or_)
+
+    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__
+
+    __iadd__ = make_proxy_method(operator.iadd)
+    __isub__ = make_proxy_method(operator.isub)
+    __imul__ = make_proxy_method(operator.imul)
+    __idiv__ = make_proxy_method(operator.idiv if PY2 else operator.itruediv)
+    __itruediv__ = make_proxy_method(operator.itruediv)
+    __ifloordiv__ = make_proxy_method(operator.ifloordiv)
+    __imod__ = make_proxy_method(operator.imod)
+    __ipow__ = make_proxy_method(operator.ipow)
+    __ilshift__ = make_proxy_method(operator.ilshift)
+    __irshift__ = make_proxy_method(operator.irshift)
+    __iand__ = make_proxy_method(operator.iand)
+    __ixor__ = make_proxy_method(operator.ixor)
+    __ior__ = make_proxy_method(operator.ior)
+    __neg__ = make_proxy_method(operator.neg)
+    __pos__ = make_proxy_method(operator.pos)
+    __abs__ = make_proxy_method(operator.abs)
+    __invert__ = make_proxy_method(operator.invert)
+
+    __int__ = make_proxy_method(int)
+
+    if PY2:
+        __long__ = make_proxy_method(long)  # noqa
+
+    __float__ = make_proxy_method(float)
+    __oct__ = make_proxy_method(oct)
+    __hex__ = make_proxy_method(hex)
+    __index__ = make_proxy_method(operator.index)
+    __len__ = make_proxy_method(len)
+    __contains__ = make_proxy_method(operator.contains)
+    __getitem__ = make_proxy_method(operator.getitem)
+    __setitem__ = make_proxy_method(operator.setitem)
+    __delitem__ = make_proxy_method(operator.delitem)
+
+    if PY2:
+        __getslice__ = make_proxy_method(operator.getslice)
+        __setslice__ = make_proxy_method(operator.setslice)
+        __delslice__ = make_proxy_method(operator.delslice)
+
+    def __enter__(self):
+        return self.__wrapped__.__enter__()
+
+    def __exit__(self, *args, **kwargs):
+        return self.__wrapped__.__exit__(*args, **kwargs)
+
+    __iter__ = make_proxy_method(iter)
+
+    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__,)