PolymorphicPointerReflector.h

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/*
 * Copyright (C) 2012 by
 *   MetraLabs GmbH (MLAB), GERMANY
 * and
 *   Neuroinformatics and Cognitive Robotics Labs (NICR) at TU Ilmenau, GERMANY
 * All rights reserved.
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 * Contact: info@mira-project.org
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#ifndef _MIRA_POLYMORPHICPOINTERREFLECTOR_H_
#define _MIRA_POLYMORPHICPOINTERREFLECTOR_H_

#include <map>

#include <utils/Foreach.h>
#include <serialization/VoidCast.h>

namespace mira {


namespace serialization {


template <typename Derived>
struct PolymorphicPointerReflectorBase
{
    virtual ~PolymorphicPointerReflectorBase() {}

    virtual void invoke(Derived& serializer, void* pointer) = 0;
};

template <typename T, typename Derived>
struct PolymorphicPointerReflector :
            public PolymorphicPointerReflectorBase<Derived>
{
    virtual void invoke(Derived& reflector, void* pointer)
    {
        // and serialize content recursively
        reflector.invokePointerObject(*serialization::void_downcast<T>(pointer));
    }
};

template <typename Derived>
class PolymorphicPointerReflectorRegistrar :
            public LazySingleton<PolymorphicPointerReflectorRegistrar<Derived> >
{
public:

    typedef PolymorphicPointerReflectorBase<Derived>* ReflectorPtr;

public:

    ~PolymorphicPointerReflectorRegistrar() {

        if(mReflectors.size()>0) {
            // If we reach here, some classes were not unregistered before this
            // singleton is destroyed. We could life with that since it is
            // not a growing memory leak and the memory will be released upon
            // the termination of the process. However, to make tools like
            // valgrind happy, we release the memory, but we do NOT call the
            // proper destructor (therefore the char* cast). Calling the
            // destructor can be dangerous especially on Windows, since some
            // necessary dynamic libraries were already removed from memory
            // for some reason. This is somewhat hackish, but no problem at all
            // since the destructors do not do anything.
            // Maybe we find a better solution some day, but this has very low
            // priority.
            foreach(typename ReflectorMap::value_type& v, mReflectors)
                delete (char*)v.second;
        }
        mReflectors.clear();
    }

public:

    template<typename Class>
    void registerClass()
    {
        int typeId = Class::CLASS().getTypeId();
        if(mReflectors.count(typeId)!=0)
            return; // we already have registered that class type

        // add a new pointer serializer
        mReflectors.insert(std::make_pair(typeId,
                                          new PolymorphicPointerReflector<Class, Derived>) );
    }

    template<typename Class>
    void unregisterClass()
    {
        int typeId = Class::CLASS().getTypeId();

        auto it = mReflectors.find(typeId);
        if(it==mReflectors.end())
            return; // we have not registered that class type,
                    // or already unregistered it

        // delete the reflector
        delete it->second;

        // and remove it from our map
        mReflectors.erase(it);
    }

    ReflectorPtr getPolymorphicPointerReflector(int typeId)
    {
        typename ReflectorMap::iterator i = mReflectors.find(typeId);
        if(mReflectors.find(typeId)==mReflectors.end())
            return ReflectorPtr(); // NULL
        return i->second;
    }

private:

    typedef std::map<int, ReflectorPtr > ReflectorMap;

    ReflectorMap mReflectors;

};


} // namespace


} // namespace

#endif