100 lines
3.4 KiB
Python
100 lines
3.4 KiB
Python
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## Original algorithm adapted from {{{ http://code.activestate.com/recipes/496741/ (r1)
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class Proxy(object):
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__slots__ = ["_obj", "__weakref__"]
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_local = {
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'_setobj':1,
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'_getobj':1
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}
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def __init__(self, obj):
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object.__setattr__(self, "_obj", obj)
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#
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# proxying (special cases)
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#
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def __getattribute__(self, name):
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if name in Proxy._local:
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return object.__getattribute__(self, name)
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return getattr(object.__getattribute__(self, "_obj"), name)
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def __delattr__(self, name):
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delattr(object.__getattribute__(self, "_obj"), name)
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def __setattr__(self, name, value):
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setattr(object.__getattribute__(self, "_obj"), name, value)
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def __nonzero__(self):
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return bool(object.__getattribute__(self, "_obj"))
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def __str__(self):
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return str(object.__getattribute__(self, "_obj"))
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def __repr__(self):
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return repr(object.__getattribute__(self, "_obj"))
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def __call__(self, *args, **kwargs):
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return object.__getattribute__(self, "_obj")(*args, **kwargs)
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def _setobj(self, newobj):
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newclass = Proxy._get_proxy(newobj)
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object.__setattr__(self, "_obj", newobj)
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object.__setattr__(self, "__class__", newclass)
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def _getobj(self):
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return object.__getattribute__(self, "_obj")
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#
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# factories
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#
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_special_names = [
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'__abs__', '__add__', '__and__', '__call__', '__cmp__', '__coerce__',
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'__contains__', '__delitem__', '__delslice__', '__div__', '__divmod__',
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'__eq__', '__float__', '__floordiv__', '__ge__', '__getitem__',
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'__getslice__', '__gt__', '__hash__', '__hex__', '__iadd__', '__iand__',
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'__idiv__', '__idivmod__', '__ifloordiv__', '__ilshift__', '__imod__',
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'__imul__', '__int__', '__invert__', '__ior__', '__ipow__', '__irshift__',
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'__isub__', '__iter__', '__itruediv__', '__ixor__', '__le__', '__len__',
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'__long__', '__lshift__', '__lt__', '__mod__', '__mul__', '__ne__',
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'__neg__', '__oct__', '__or__', '__pos__', '__pow__', '__radd__',
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'__rand__', '__rdiv__', '__rdivmod__', '__reduce__', '__reduce_ex__',
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'__repr__', '__reversed__', '__rfloorfiv__', '__rlshift__', '__rmod__',
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'__rmul__', '__ror__', '__rpow__', '__rrshift__', '__rshift__', '__rsub__',
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'__rtruediv__', '__rxor__', '__setitem__', '__setslice__', '__sub__',
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'__truediv__', '__xor__', 'next'
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]
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@classmethod
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def _get_proxy(cls, obj):
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try:
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cache = cls.__dict__["_class_proxy_cache"]
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except KeyError:
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cls._class_proxy_cache = cache = {}
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try:
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theclass = cache[obj.__class__]
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except KeyError:
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cache[obj.__class__] = theclass = cls._create_class_proxy(obj.__class__)
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return theclass
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@classmethod
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def _create_class_proxy(cls, theclass):
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"""creates a proxy for the given class"""
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def make_method(name):
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def method(self, *args, **kw):
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return getattr(object.__getattribute__(self, "_obj"), name)(*args, **kw)
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return method
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namespace = {}
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for name in cls._special_names:
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if hasattr(theclass, name) and not hasattr(cls, name):
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namespace[name] = make_method(name)
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return type("%s(%s)" % (cls.__name__, theclass.__name__), (cls,), namespace)
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def __new__(cls, obj, *args, **kwargs):
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"""
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creates an proxy instance referencing `obj`. (obj, *args, **kwargs) are
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passed to this class' __init__, so deriving classes can define an
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__init__ method of their own.
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note: _class_proxy_cache is unique per deriving class (each deriving
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class must hold its own cache)
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"""
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theclass = cls._get_proxy(obj)
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ins = object.__new__(theclass)
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#theclass.__init__(ins, obj, *args, **kwargs)
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return ins
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