Accessor.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.
 *
 * Contact: info@mira-project.org
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 *   Foundation and appearing in the file LICENSE.GPL3 included in the
 *   packaging of this file. Please review the following information to
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#ifndef _MIRA_ACCESSOR_H_
#define _MIRA_ACCESSOR_H_

#include <serialization/GetterSetter.h>
#include <serialization/SplitReflect.h>

namespace mira {


template<typename T> class AccessorGetterPartInternalRedirect;

template <typename T, typename SerializerTag>
class IsTransparentSerializable<AccessorGetterPartInternalRedirect<T>,SerializerTag> : public std::true_type {};

template<typename T>
class AccessorGetterPart
{
public:
    typedef T value_type;

    static const bool isDirectGetter = true;

public:
    AccessorGetterPart(const T& value) : internal(value) {}

public:
    const value_type& get() const {
        return internal.get();
    }

public:
    template<typename Reflector>
    void reflectRead(Reflector& r) {
        r.delegate(internal);
    }

private:
    AccessorGetterPartInternalRedirect<T> internal;
};

template<typename T>
class AccessorGetterPartInternalRedirect
{
public:
    typedef T value_type;

    static const bool isDirectGetter = true;

public:
    AccessorGetterPartInternalRedirect(const T& value) : getter((T*)&value) {}

public:
    const value_type& get() const {
        return *getter;
    }

public:
    template<typename Reflector>
    void reflect(Reflector& r) {
        r.delegate(*getter);
    }

private:
    T*        getter; // for reading
};

//specialization for getters
template <typename T>
struct AccessorGetterPart<Getter<T>>
{
public:
    typedef T value_type;

    static const bool isDirectGetter = false;

public:
    AccessorGetterPart(const Getter<T>& iGetter) : getter(iGetter) {}

public:
    value_type get() const {
        return getter.get();
    }

public:
    template<typename Reflector>
    void reflectRead(Reflector& r) {
        r.delegate(getter);
    }

private:
    Getter<T> getter; // for reading
};


template<typename T>
class AccessorSetterPart {
    static_assert(sizeof(T)==0, "Not implemented for direct access. "
                                "There was no need yet");
};

// specialization for setters
template<typename T>
class AccessorSetterPart<Setter<T>>
{
public:
    typedef T value_type;

public:
    AccessorSetterPart(const Setter<T>& iSetter) : setter(iSetter) {}

public:
    void set(const value_type& value) {
        setter.set(value);
    }

public:
    template<typename Reflector>
    void reflectWrite(Reflector& r) {
        r.delegate(setter);
    }

private:
    Setter<T> setter; // for writing
};

template <typename T>
class NullSetter {};

// specialization for "Null"-Setter, that does nothing
template<typename T>
class AccessorSetterPart<NullSetter<T>>
{
public:
    typedef T value_type;

public:
    AccessorSetterPart() {}
    AccessorSetterPart(const NullSetter<T>&) {}

public:
    void set(const value_type& value) {}

public:
    template<typename Reflector>
    void reflectWrite(Reflector& r) {
    }
};



template <typename Getter, typename Setter>
class Accessor : public AccessorGetterPart<Getter>,
                 public AccessorSetterPart<Setter>
{
    typedef AccessorGetterPart<Getter> GetterPart;
    typedef AccessorSetterPart<Setter> SetterPart;

public:
    Accessor(const Getter& getter, const Setter& setter) :
        AccessorGetterPart<Getter>(getter), AccessorSetterPart<Setter>(setter) {}

    Accessor(const Getter& getter) :
        AccessorGetterPart<Getter>(getter) {} // for null setter

public:

    static_assert(std::is_same<typename GetterPart::value_type,
                               typename SetterPart::value_type>::value,
            "Type of value in Getter and Setter must be the same");

    typedef typename GetterPart::value_type value_type;

    typedef decltype(std::declval<GetterPart>().get()) GetReturnValueType;

    Accessor& operator=(const value_type& value) {
        this->set(value);
        return *this;
    }

    operator GetReturnValueType() const { return this->get(); }

public:

    MIRA_SPLIT_REFLECT_MEMBER
    // reflectRead and reflectWrite are implemented in AccessorGetterPart and
    // AccessorSetterPart.
};

// mark the Accessor as transparent serializable (internal detail)
template <typename Getter, typename Setter, typename SerializerTag>
class IsTransparentSerializable<Accessor<Getter,Setter>,SerializerTag> : public std::true_type {};


template <typename Getter, typename Setter>
Accessor<Getter,Setter> makeAccessor(const Getter& getter, const Setter& setter) {
    return Accessor<Getter,Setter>(getter,setter);
}


} // namespace

#endif