v.hpp

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/*
 * Copyright 2018, Intel Corporation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
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 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
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 *       distribution.
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 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 */
 
#ifndef LIBPMEMOBJ_CPP_V_HPP
#define LIBPMEMOBJ_CPP_V_HPP
 
#include <memory>
 
#include <libpmemobj++/detail/common.hpp>
#include <libpmemobj++/detail/volatile.hpp>
 
namespace pmem
{
 
namespace obj
{
 
namespace experimental
{
 
template <typename T>
class v {
    using this_type = v<T>;
 
    template <typename N>
    friend class v;
 
public:
    v() noexcept : vlt{0}
    {
    }
 
    v &
    operator=(const v &rhs)
    {
        /* make sure object is initialized */
        (void)get();
 
        val = rhs.val;
 
        return *this;
    }
 
    v &
    operator=(const T &rhs)
    {
        /* make sure object is initialized */
        (void)get();
 
        val = rhs;
 
        return *this;
    }
 
    template <typename Y,
          typename = typename std::enable_if<
              std::is_convertible<Y, T>::value>::type>
    v &
    operator=(const v<Y> &rhs)
    {
        /* make sure object is initialized */
        (void)get();
 
        val = rhs.val;
 
        return *this;
    }
 
    T &
    get() noexcept
    {
        PMEMobjpool *pop = pmemobj_pool_by_ptr(this);
        if (pop == NULL)
            return this->val;
 
        T *value = static_cast<T *>(pmemobj_volatile(
            pop, &this->vlt, &this->val, sizeof(T),
            pmem::detail::instantiate_volatile_object<T>, NULL));
 
        return *value;
    }
 
    operator T &() noexcept
    {
        return this->get();
    }
 
    void
    swap(v &other)
    {
        /* make sure object is initialized */
        (void)get();
 
        std::swap(this->val, other.val);
    }
 
private:
    struct pmemvlt vlt;
    T val;
};
 
template <class T>
inline void
swap(v<T> &a, v<T> &b)
{
    a.swap(b);
}
 
} /* namespace experimental */
 
} /* namespace obj */
 
} /* namespace pmem */
 
#endif /* LIBPMEMOBJ_CPP_V_HPP */