Sorry just as a quick append, UseComponentWrap inherits from UseComponent to
allow overriding of a few virtual methods
On 2011-11-08, at 1:13 AM, "Jay Riley" <super24bitso...@hotmail.com> wrote:
> I'm trying to pass an object from python to C++. I want C++ to take control
> of the object.
>
> The object I'm trying to change ownership on is defined in it's module as
> follows (superfluous code removed):
>
>
> BOOST_PYTHON_MODULE(ComponentModule)
> {
>
> class_<Components::Component,
> std::auto_ptr<Components::Component> >("Component")
> .def(init<>())
> .def(init<bool, boost::python::optional<const
> int> >())
> .def(init<const std::string&, int,
> boost::python::optional<bool, const int> >())
> .def(init<const std::string&, const
> std::string&, boost::python::optional<bool, const int> >())
> ;
>
> class_<Components::UseComponent,
> std::auto_ptr<UseComponentWrap>, bases<Components::Component>
> >("UseComponent")
> .def(init<>())
> .def(init<const std::string&,bool, bool>())
> .def(init<const Components::UseComponent&>())
> ;
> }
> }
>
> And The object I want to take control is:
>
> BOOST_PYTHON_MODULE(ItemModule)
> {
>
> class_<Items::Item, bases<Entity> >("Item")
> .def(init<Items::Item&>())
> .def(init<const std::string&>())
>
> .def("RegisterComponent",&Items::Item::RegisterComponent )
> ;
> }
>
> Register Component is the function that takes control of the component. It's
> full definition is:
>
> void Item::RegisterComponent(const std::string& indexName,
> Components::Component* component)
> {
> auto it = ComponentCollection.find(indexName);
> if (it != ComponentCollection.end())
> {
> delete it->second;
> ComponentCollection.erase(it);
> ComponentCollection[indexName] = component;
> }
>
> The item posses the component until destroyed/overwritten.
>
> A sample piece of python code would be:
>
> healer = UseComponent("HealUseModule", True, True)
> print "Adding Healing Component"
> CurrentItem.RegisterComponent("Healing Component", healer)
>
> where CurrentItem is an item. The problem here is that when the component
> goes out of scope in the python file, it get's deleted adn invalidated since
> C++ hasn't taken ownership of it. I tried following the advice here
>
> http://www.boost.org/doc/libs/1_36_0/libs/python/doc/v2/faq.html#ownership
>
> which is why I wrapped Component/UseComponent in an auto_ptr. Additionally
> fro, this advice, I changed to RegisterComponent wrap to
>
> .def("RegisterComponent", &RegisterComp)
>
> where RegisterComp is
>
> void RegisterComp(Items::Item& item, const std::string& compName,
> std::auto_ptr<Components::UseComponent> comp)//, void* comp)
> {
> item.RegisterComponent(compName, comp.get());
> comp.release();
> }
>
> this fails, saying the Python argument types did not match the C++ signature.
> I'm certain it's the std::auto_ptr<Components::UseComponent> comp argument
> that is invalid because the call succeeds when that argument is removed but
> item and name are left.
>
> Am I doing something wrong? base on that snippet it should work. Is there
> another way to do this? I know I should probably switch to smart_ptrs and I'm
> considering it, but Id like to be able to know how to do this, even if its
> just for future reference. Any help would be appreciated.
>
> Thanks
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