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# -*- coding: utf-8; fill-column: 77 -*-
# -*- indent-tabs-mode: nil -*-
# This file is part of pyutil; see README.rst for licensing terms.
import warnings
# from the Python Standard Library
from weakref import ref
import types
# from the pyutil library
from .assertutil import precondition
def is_bound_method(fn):
if hasattr(types, 'UnboundMethodType'): # PY2
return hasattr(fn, 'im_self')
else: # PY3
return isinstance(fn, types.MethodType)
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(is_bound_method(fn), "fn is required to be a bound method.")
self._cleanupcallback = callback
self._obj = ref(fn.__self__, self.call_cleanup_cb)
self._meth = fn.__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 is_bound_method(o):
return WeakMethod(o)
else:
return o
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