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pilotclient/src/blackmisc/inheritancetraits.h

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/* Copyright (C) 2015
* swift project Community / Contributors
*
* This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
* directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
* including this file, may be copied, modified, propagated, or distributed except according to the terms
* contained in the LICENSE file.
*/
//! \file
#ifndef BLACKMISC_INHERITANCE_TRAITS_H
#define BLACKMISC_INHERITANCE_TRAITS_H
#include "typetraits.h"
#include <QMetaType>
#include <type_traits>
namespace BlackMisc
{
class CPropertyIndex;
/*!
* If T has a member typedef base_type, this trait will obtain it, otherwise void.
*/
template <typename T, typename = void_t<>>
struct BaseOf
{
using type = void; //!< void
};
//! \cond
template <typename T>
struct BaseOf<T, void_t<typename T::base_type>>
{
using type = typename T::base_type; //!< T::base_type
};
//! \endcond
/*!
* It T has a member typedef base_type which is a registered metatype, this trait will obtain it, otherwise void.
*/
template <class T>
struct MetaBaseOf
{
//! Type of T::base_type, or void if not declared.
using type = std::conditional_t<QMetaTypeId<typename BaseOf<T>::type>::Defined, typename BaseOf<T>::type, void>;
};
/*!
* If T has a member typedef base_type which has a member propertyByIndex, this trait will obtain it, otherwise void.
*/
template <typename T, typename = void_t<>>
struct IndexBaseOf
{
using type = void; //!< void
};
//! \cond
template <typename T>
struct IndexBaseOf<T, void_t<decltype(std::declval<typename T::base_type>().propertyByIndex(std::declval<CPropertyIndex>()))>>
{
using type = typename T::base_type; //!< T::base_type
};
//! \endcond
/*!
* Alias for typename BaseOf<T>::type.
*/
template <class T>
using BaseOfT = typename BaseOf<T>::type;
/*!
* Alias for typename MetaBaseOf<T>::type.
*/
template <class T>
using MetaBaseOfT = typename MetaBaseOf<T>::type;
/*!
* Alias for typename IndexBaseOf<T>::type.
*/
template <class T>
using IndexBaseOfT = typename IndexBaseOf<T>::type;
}
#endif