YiLazy_impl.h

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// © You i Labs Inc. 2000-2017. All rights reserved.
#ifndef _YI_LAZY_IMPL_H
#define _YI_LAZY_IMPL_H

#if !defined(_YI_LAZY_H_)
#error "Do not include YiLazy_impl.h directly. Please include YiLazy.h instead."
#endif

#include "utility/YiLazy.h"

template<class YI_CLASS>
inline CYILazy<YI_CLASS>::CYILazy() :
    m_pInstance(nullptr)
{
}

template<class YI_CLASS>
inline CYILazy<YI_CLASS>::~CYILazy()
{
    YI_CLASS *pInstance = m_pInstance.load();
    if (pInstance)
    {
        delete pInstance;
        m_pInstance.store(nullptr);
    }
}

template<class YI_CLASS>
inline const YI_CLASS *CYILazy<YI_CLASS>::Get() const
{
    YI_CLASS *pInstance = m_pInstance.load();
    if (pInstance == nullptr)
    {
        pInstance = new YI_CLASS();
        YI_CLASS *pNullInstance = nullptr;
        if (!m_pInstance.compare_exchange_strong(pNullInstance, pInstance))
        {
            delete pInstance;
            pInstance = m_pInstance.load();
        }
    }
    return pInstance;
}

template<class YI_CLASS>
inline YI_CLASS *CYILazy<YI_CLASS>::Get()
{
    return const_cast<YI_CLASS *>(const_cast<const CYILazy<YI_CLASS> &>(*this).Get());
}

template<class YI_CLASS>
inline const YI_CLASS *CYILazy<YI_CLASS>::TryGet() const
{
    return m_pInstance.load();
}

template<class YI_CLASS>
inline YI_CLASS *CYILazy<YI_CLASS>::TryGet()
{
    return m_pInstance.load();
}

#endif /* _YI_LAZY_IMPL_H */