memgraph/include/mvcc/version.hpp

#pragma once

#include <atomic>

namespace mvcc
{

template <class T>
class Version
{
public:
    Version() = default;
    Version(T* older) : older(older) {}

    ~Version()
    {
        delete older.load(std::memory_order_seq_cst);
    }

    // return a pointer to an older version stored in this record
    T* next(std::memory_order order = std::memory_order_seq_cst)
    {
        return older.load(order);
    }

    const T* next(std::memory_order order = std::memory_order_seq_cst) const
    {
        return older.load(order);
    }

    // set the older version of this record
    void next(T* value, std::memory_order order = std::memory_order_seq_cst)
    {
        older.store(value, order);
    }

private:
    std::atomic<T*> older {nullptr};
};

}