python - How to make my SWIG extension module work with Pickle?

Question

I have an extension module for Python that uses SWIG as a wrapper and I try to serialize it with Pickle and I fail =)

1. If anyone has a source of SWIG extension that can be pickled, would love to see it!
2. It seems like I should implement __reduce_ex__ method in my C++ code. Does anyone have example of __reduce_ex__? There is similar Stackoverflow question but it omits manager_constructor specification and implementation.

Answer 1

Seems like I found simlple solution that works for me:

So let's say we have class C that was generated with SWIG, then we wrap it with

class PickalableC(C, PickalableSWIG):

    def __init__(self, *args):
        self.args = args
        C.__init__(self)

where PickalableSWIG is

class PickalableSWIG:

    def __setstate__(self, state):
        self.__init__(*state['args'])

    def __getstate__(self):
        return {'args': self.args}

Then

pickle.loads(pickle.dumps(C()))

fails, but

pickle.loads(pickle.dumps(PickalableC()))

succeeds =)