rippled/include/xrpl/basics/SharedWeakCachePointer.ipp

#ifndef XRPL_BASICS_SHAREDWEAKCACHEPOINTER_IPP_INCLUDED
#define XRPL_BASICS_SHAREDWEAKCACHEPOINTER_IPP_INCLUDED

#include <xrpl/basics/SharedWeakCachePointer.h>

namespace xrpl {
template <class T>
SharedWeakCachePointer<T>::SharedWeakCachePointer(
    SharedWeakCachePointer const& rhs) = default;

template <class T>
template <class TT>
    requires std::convertible_to<TT*, T*>
SharedWeakCachePointer<T>::SharedWeakCachePointer(
    std::shared_ptr<TT> const& rhs)
    : combo_{rhs}
{
}

template <class T>
SharedWeakCachePointer<T>::SharedWeakCachePointer(
    SharedWeakCachePointer&& rhs) = default;

template <class T>
template <class TT>
    requires std::convertible_to<TT*, T*>
SharedWeakCachePointer<T>::SharedWeakCachePointer(std::shared_ptr<TT>&& rhs)
    : combo_{std::move(rhs)}
{
}

template <class T>
SharedWeakCachePointer<T>&
SharedWeakCachePointer<T>::operator=(SharedWeakCachePointer const& rhs) =
    default;

template <class T>
template <class TT>
    requires std::convertible_to<TT*, T*>
SharedWeakCachePointer<T>&
SharedWeakCachePointer<T>::operator=(std::shared_ptr<TT> const& rhs)
{
    combo_ = rhs;
    return *this;
}

template <class T>
template <class TT>
    requires std::convertible_to<TT*, T*>
SharedWeakCachePointer<T>&
SharedWeakCachePointer<T>::operator=(std::shared_ptr<TT>&& rhs)
{
    combo_ = std::move(rhs);
    return *this;
}

template <class T>
SharedWeakCachePointer<T>::~SharedWeakCachePointer() = default;

// Return a strong pointer if this is already a strong pointer (i.e. don't
// lock the weak pointer. Use the `lock` method if that's what's needed)
template <class T>
std::shared_ptr<T> const&
SharedWeakCachePointer<T>::getStrong() const
{
    static std::shared_ptr<T> const empty;
    if (auto p = std::get_if<std::shared_ptr<T>>(&combo_))
        return *p;
    return empty;
}

template <class T>
SharedWeakCachePointer<T>::operator bool() const noexcept
{
    return !!std::get_if<std::shared_ptr<T>>(&combo_);
}

template <class T>
void
SharedWeakCachePointer<T>::reset()
{
    combo_ = std::shared_ptr<T>{};
}

template <class T>
T*
SharedWeakCachePointer<T>::get() const
{
    return std::get_if<std::shared_ptr<T>>(&combo_).get();
}

template <class T>
std::size_t
SharedWeakCachePointer<T>::use_count() const
{
    if (auto p = std::get_if<std::shared_ptr<T>>(&combo_))
        return p->use_count();
    return 0;
}

template <class T>
bool
SharedWeakCachePointer<T>::expired() const
{
    if (auto p = std::get_if<std::weak_ptr<T>>(&combo_))
        return p->expired();
    return !std::get_if<std::shared_ptr<T>>(&combo_);
}

template <class T>
std::shared_ptr<T>
SharedWeakCachePointer<T>::lock() const
{
    if (auto p = std::get_if<std::shared_ptr<T>>(&combo_))
        return *p;

    if (auto p = std::get_if<std::weak_ptr<T>>(&combo_))
        return p->lock();

    return {};
}

template <class T>
bool
SharedWeakCachePointer<T>::isStrong() const
{
    if (auto p = std::get_if<std::shared_ptr<T>>(&combo_))
        return !!p->get();
    return false;
}

template <class T>
bool
SharedWeakCachePointer<T>::isWeak() const
{
    return !isStrong();
}

template <class T>
bool
SharedWeakCachePointer<T>::convertToStrong()
{
    if (isStrong())
        return true;

    if (auto p = std::get_if<std::weak_ptr<T>>(&combo_))
    {
        if (auto s = p->lock())
        {
            combo_ = std::move(s);
            return true;
        }
    }
    return false;
}

template <class T>
bool
SharedWeakCachePointer<T>::convertToWeak()
{
    if (isWeak())
        return true;

    if (auto p = std::get_if<std::shared_ptr<T>>(&combo_))
    {
        combo_ = std::weak_ptr<T>(*p);
        return true;
    }

    return false;
}
}  // namespace xrpl
#endif