Fetching contributors…
Cannot retrieve contributors at this time
43 lines (32 sloc) 1.34 KB
# Copyright (c) 2005-2010 Zooko Wilcox-O'Hearn
# This file is part of pyutil; see README.rst for licensing terms.
import warnings
# from the Python Standard Library
from weakref import ref
# from the pyutil library
from assertutil import precondition
# Thanks to Thomas Wouters, JP Calderone and the authors from the Python Cookbook.
# class WeakMethod copied from The Python Cookbook and simplified.
class WeakMethod:
""" Wraps a function or, more importantly, a bound method, in
a way that allows a bound method's object to be GC'd """
def __init__(self, fn, callback=None):
warnings.warn("deprecated", DeprecationWarning)
precondition(hasattr(fn, 'im_self'), "fn is required to be a bound method.")
self._cleanupcallback = callback
self._obj = ref(fn.im_self, self.call_cleanup_cb)
self._meth = fn.im_func
def __call__(self, *args, **kws):
s = self._obj()
if s:
return self._meth(s, *args,**kws)
def __repr__(self):
return "<%s %s %s>" % (self.__class__.__name__, self._obj, self._meth,)
def call_cleanup_cb(self, thedeadweakref):
if self._cleanupcallback is not None:
self._cleanupcallback(self, thedeadweakref)
def factory_function_name_here(o):
if hasattr(o, 'im_self'):
return WeakMethod(o)
return o