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42 lines
1.3 KiB
42 lines
1.3 KiB
# Copyright (c) 2005-2010 Zooko Wilcox-O'Hearn
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# This file is part of pyutil; see README.rst for licensing terms.
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import warnings
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# from the Python Standard Library
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from weakref import ref
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# from the pyutil library
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from assertutil import precondition
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# Thanks to Thomas Wouters, JP Calderone and the authors from the Python Cookbook.
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# class WeakMethod copied from The Python Cookbook and simplified.
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class WeakMethod:
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""" Wraps a function or, more importantly, a bound method, in
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a way that allows a bound method's object to be GC'd """
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def __init__(self, fn, callback=None):
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warnings.warn("deprecated", DeprecationWarning)
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precondition(hasattr(fn, 'im_self'), "fn is required to be a bound method.")
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self._cleanupcallback = callback
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self._obj = ref(fn.im_self, self.call_cleanup_cb)
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self._meth = fn.im_func
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def __call__(self, *args, **kws):
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s = self._obj()
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if s:
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return self._meth(s, *args,**kws)
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def __repr__(self):
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return "<%s %s %s>" % (self.__class__.__name__, self._obj, self._meth,)
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def call_cleanup_cb(self, thedeadweakref):
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if self._cleanupcallback is not None:
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self._cleanupcallback(self, thedeadweakref)
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def factory_function_name_here(o):
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if hasattr(o, 'im_self'):
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return WeakMethod(o)
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else:
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return o
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