Wrapping c++ shared pointers

#distutils: language=c++

from libcpp.memory cimport shared_ptr
from cpython.buffer cimport PyObject_GetBuffer, PyBUF_FULL

cdef extern from *:
    cdef cppclass CppObj:
        pass
    cdef shared_ptr[CppObj] cpp_function(Py_buffer *buf)


cdef class PyObj:
    cdef shared_ptr[CppObj] _ptr

    @staticmethod
    cdef create(shared_ptr[CppObj] ptr):
        cdef PyObj py_obj = PyObj()
        py_obj._ptr = ptr

        return py_obj

cdef test_wrap(mat):

    cdef Py_buffer buf
    PyObject_GetBuffer(mat, &buf, PyBUF_FULL)

    cdef shared_ptr[CppObj] obj_ptr = cpp_function(&buf)

    return PyObj.create(obj_ptr)