#include <cassert>
#include <fstream>

#include <boost/shared_ptr.hpp>
#include <boost/weak_ptr.hpp>

#include <boost/serialization/serialization.hpp>

#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/xml_iarchive.hpp>
#include <boost/serialization/nvp.hpp>

#include <boost/serialization/export.hpp>

#include <boost/serialization/shared_ptr.hpp>
#include <boost/serialization/weak_ptr.hpp>

class Left;
typedef boost::shared_ptr<Left> LeftSp;

class Right;
typedef boost::shared_ptr<Right> RightSp;

class Bottom;
typedef boost::shared_ptr<Bottom> BottomSp;
typedef boost::weak_ptr<Bottom> BottomWp;

class Left {
public:
    Left() {}
    virtual ~Left() {}
private:
    // serialize
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & /*ar*/, const unsigned int /* file_version */) {}
};

BOOST_CLASS_EXPORT(Left)

class Right {
public:
    Right() {}
    virtual ~Right() {}
private:
    // serialize
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & /*ar*/, const unsigned int /* file_version */) {}
};

BOOST_CLASS_EXPORT(Right)

class Bottom:public Left, public Right {
public:
    virtual ~Bottom() {}
    static BottomSp create()
    {
        BottomSp sp(new Bottom);
        sp->setWp(sp);
        return sp;
    }
private:
    BottomWp wp_;

    Bottom() {}
    void setWp(BottomSp sp) { wp_ = sp; }

    // serialize
    friend class boost::serialization::access;
    template<class Archive>
    void save(Archive &ar, const unsigned int /* file_version */) const
    {
        ar << BOOST_SERIALIZATION_BASE_OBJECT_NVP(Left);
        ar << BOOST_SERIALIZATION_BASE_OBJECT_NVP(Right);
        ar << BOOST_SERIALIZATION_NVP(wp_); // *1
    }
    template<class Archive>
    void load(Archive & ar, const unsigned int /* file_version */)
    {
        ar >> BOOST_SERIALIZATION_BASE_OBJECT_NVP(Left);
        ar >> BOOST_SERIALIZATION_BASE_OBJECT_NVP(Right);
        ar >> BOOST_SERIALIZATION_NVP(wp_); // *2
    }
    BOOST_SERIALIZATION_SPLIT_MEMBER()
};

BOOST_CLASS_EXPORT(Bottom)

class Holder {
public:
    LeftSp mbl_;  // shared_ptr<Left>
    RightSp mbr_; // shared_ptr<Right>

    Holder() {} // for serialize
    Holder(BottomSp l, BottomSp r):mbl_(l) ,mbr_(r) {} // for appli construct

    // serialize
    friend class boost::serialization::access;
    template<class Archive>
    void save(Archive &ar, const unsigned int /* file_version */) const
    {
        // polymophic serialize via shared_ptr
        ar << BOOST_SERIALIZATION_NVP(mbl_);
        // polymophic serialize via shared_ptr
        ar << BOOST_SERIALIZATION_NVP(mbr_);
    }
    template<class Archive>
    void load(Archive & ar, const unsigned int /* file_version */)
    {
        // polymophic de-serialize via shared_ptr
        ar >> BOOST_SERIALIZATION_NVP(mbl_);
        // polymophic de-serialize via shared_ptr
        ar >> BOOST_SERIALIZATION_NVP(mbr_);
    }
    BOOST_SERIALIZATION_SPLIT_MEMBER()
};

BOOST_CLASS_EXPORT(Holder)

int main()
{

    {
        // serialize
        Holder h1(Bottom::create(), Bottom::create());
        std::ofstream ofs("output.xml");
        assert(ofs);
        boost::archive::xml_oarchive oa(ofs);
        oa << boost::serialization::make_nvp("Holder", h1);
    }
    {
        // de-serialize
        Holder h2;
        std::ifstream ifs("output.xml");
        assert(ifs);
        boost::archive::xml_iarchive ia(ifs);
        ia >> boost::serialization::make_nvp("Holder", h2);

        // check
        Left *pLeft = h2.mbl_.get();
        Bottom *pBottomFromLeft = dynamic_cast<Bottom *>(pLeft);

        Right *pRight = h2.mbr_.get();
        Bottom *pBottomFromRight = dynamic_cast<Bottom *>(pRight);

        assert(pBottomFromLeft);  // Success
        assert(pBottomFromRight); // Fail. Comment out *1 and *2, it works corrctly.
    }
}

// output.xml
// 
// <?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
// <!DOCTYPE boost_serialization>
// <boost_serialization signature="serialization::archive" version="5">
// <Holder class_id="0" tracking_level="1" version="0" object_id="_0">
//     <mbl_ class_id="1" tracking_level="0" version="1">
//         <px class_id="3" class_name="Bottom" tracking_level="1" version="0" object_id="_1">
//             <Left class_id="2" tracking_level="1" version="0" object_id="_2"></Left>
//             <Right class_id="4" tracking_level="1" version="0" object_id="_3"></Right>
//             <wp_ class_id="5" tracking_level="0" version="0">
//                 <shared_ptr class_id="6" tracking_level="0" version="1">
//                     <px class_id_reference="3" object_id_reference="_1"></px>
//                 </shared_ptr>
//             </wp_>
//         </px>
//     </mbl_>
//     <mbr_ class_id="7" tracking_level="0" version="1">
//         <px class_id_reference="3" object_id="_4">
//             <Left object_id="_5"></Left>
//             <Right object_id="_6"></Right>
//             <wp_>
//                 <shared_ptr>
//                     <px class_id_reference="3" object_id_reference="_4"></px>
//                 </shared_ptr>
//             </wp_>
//         </px>
//     </mbr_>
// </Holder>
// </boost_serialization>