persistent_pool_ptr.hpp

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// SPDX-License-Identifier: BSD-3-Clause
/* Copyright 2018-2021, Intel Corporation */
 
#ifndef PMEMOBJ_PERSISTENT_POOL_PTR_HPP
#define PMEMOBJ_PERSISTENT_POOL_PTR_HPP
 
#include <cassert>
#include <cstddef>
#include <type_traits>
 
#include <libpmemobj++/detail/specialization.hpp>
#include <libpmemobj++/persistent_ptr.hpp>
 
namespace pmem
{
namespace detail
{
 
template <typename T>
class persistent_pool_ptr {
    template <typename Y>
    friend class persistent_pool_ptr;
 
    typedef persistent_pool_ptr<T> this_type;
 
public:
    typedef typename pmem::detail::sp_element<T>::type element_type;
 
    persistent_pool_ptr() : off(0)
    {
        verify_type();
    }
 
    persistent_pool_ptr(std::nullptr_t) noexcept : off(0)
    {
        verify_type();
    }
 
    persistent_pool_ptr(PMEMoid oid) noexcept : off(oid.off)
    {
        verify_type();
    }
 
    persistent_pool_ptr(uint64_t _off) noexcept : off(_off)
    {
        verify_type();
    }
 
    template <typename Y,
          typename = typename std::enable_if<
              std::is_convertible<Y *, T *>::value>::type>
    persistent_pool_ptr(const persistent_pool_ptr<Y> &r) noexcept
        : off(r.off)
    {
        verify_type();
    }
 
    template <typename Y,
          typename = typename std::enable_if<
              std::is_convertible<Y *, T *>::value>::type>
    persistent_pool_ptr(const pmem::obj::persistent_ptr<Y> &r) noexcept
        : off(r.raw().off)
    {
        verify_type();
    }
 
    /*
     * Copy constructor.
     *
     * @param r Persistent pool pointer to the same type.
     */
    persistent_pool_ptr(const persistent_pool_ptr &r) noexcept : off(r.off)
    {
        verify_type();
    }
 
    /*
     * Copy constructor from a persistent_ptr.
     *
     * @param r Persistent pointer to the same type.
     */
    persistent_pool_ptr(const pmem::obj::persistent_ptr<T> &r) noexcept
        : off(r.raw().off)
    {
        verify_type();
    }
 
    persistent_pool_ptr(persistent_pool_ptr &&r) noexcept
        : off(std::move(r.off))
    {
        verify_type();
    }
 
    persistent_pool_ptr &
    operator=(persistent_pool_ptr &&r)
    {
        conditional_add_to_tx(this);
        this->off = std::move(r.off);
 
        return *this;
    }
 
    persistent_pool_ptr &operator=(std::nullptr_t)
    {
        conditional_add_to_tx(this);
        this->off = 0;
 
        return *this;
    }
 
    persistent_pool_ptr &
    operator=(const persistent_pool_ptr &r)
    {
        conditional_add_to_tx(this);
        this->off = r.off;
 
        return *this;
    }
 
    persistent_pool_ptr &
    operator=(const pmem::obj::persistent_ptr<T> &r)
    {
        conditional_add_to_tx(this);
        this->off = r.raw().off;
 
        return *this;
    }
 
    persistent_pool_ptr &
    operator=(const PMEMoid &oid)
    {
        conditional_add_to_tx(this);
        this->off = oid.off;
        return *this;
    }
 
    template <typename Y,
          typename = typename std::enable_if<
              std::is_convertible<Y *, T *>::value>::type>
    persistent_pool_ptr &
    operator=(const persistent_pool_ptr<Y> &r)
    {
        conditional_add_to_tx(this);
        this->off = r.off;
 
        return *this;
    }
 
    template <typename Y,
          typename = typename std::enable_if<
              std::is_convertible<Y *, T *>::value>::type>
    persistent_pool_ptr &
    operator=(const pmem::obj::persistent_ptr<Y> &r)
    {
        conditional_add_to_tx(this);
        this->off = r.raw().off;
 
        return *this;
    }
 
    element_type *
    get(uint64_t pool_uuid) const noexcept
    {
        PMEMoid oid = {pool_uuid, this->off};
        return static_cast<element_type *>(pmemobj_direct(oid));
    }
 
    element_type *
    operator()(uint64_t pool_uuid) const noexcept
    {
        return get(pool_uuid);
    }
 
    pmem::obj::persistent_ptr<T>
    get_persistent_ptr(uint64_t pool_uuid) const noexcept
    {
        PMEMoid oid = {pool_uuid, this->off};
        return pmem::obj::persistent_ptr<T>(oid);
    }
 
    void
    swap(persistent_pool_ptr &other)
    {
        conditional_add_to_tx(this);
        conditional_add_to_tx(&other);
        std::swap(this->off, other.off);
    }
 
    /*
     * Bool conversion operator.
     */
    explicit operator bool() const noexcept
    {
        return this->off != 0;
    }
 
    PMEMoid
    raw_oid(uint64_t pool_uuid) const noexcept
    {
        PMEMoid oid = {pool_uuid, this->off};
        return oid;
    }
 
    const uint64_t &
    raw() const noexcept
    {
        return this->off;
    }
 
    uint64_t &
    raw()
    {
        conditional_add_to_tx(this);
        return this->off;
    }
 
    inline persistent_pool_ptr<T> &
    operator++()
    {
        conditional_add_to_tx(this);
        this->off += sizeof(T);
 
        return *this;
    }
 
    inline persistent_pool_ptr<T>
    operator++(int)
    {
        persistent_pool_ptr<T> ret(*this);
        ++(*this);
 
        return ret;
    }
 
    inline persistent_pool_ptr<T> &
    operator--()
    {
        conditional_add_to_tx(this);
        this->off -= sizeof(T);
 
        return *this;
    }
 
    inline persistent_pool_ptr<T>
    operator--(int)
    {
        persistent_pool_ptr<T> ret(*this);
        --(*this);
 
        return ret;
    }
 
    inline persistent_pool_ptr<T> &
    operator+=(std::ptrdiff_t s)
    {
        conditional_add_to_tx(this);
        this->off += s * sizeof(T);
 
        return *this;
    }
 
    inline persistent_pool_ptr<T> &
    operator-=(std::ptrdiff_t s)
    {
        conditional_add_to_tx(this);
        this->off -= s * sizeof(T);
 
        return *this;
    }
 
    inline persistent_pool_ptr<T>
    operator+(std::ptrdiff_t s)
    {
        persistent_pool_ptr<T> ret(*this);
        ret.off += s * sizeof(T);
 
        return ret;
    }
 
    inline persistent_pool_ptr<T>
    operator-(std::ptrdiff_t s)
    {
        persistent_pool_ptr<T> ret(*this);
        ret.off -= s * sizeof(T);
 
        return ret;
    }
 
private:
    /* offset of persistent object in a persistent memory pool */
    uint64_t off;
 
    void
    verify_type()
    {
        static_assert(!std::is_polymorphic<element_type>::value,
                  "Polymorphic types are not supported");
    }
};
 
template <typename T, typename Y>
inline bool
operator==(const persistent_pool_ptr<T> &lhs,
       const persistent_pool_ptr<Y> &rhs) noexcept
{
    return lhs.raw() == rhs.raw();
}
 
template <typename T, typename Y>
inline bool
operator!=(const persistent_pool_ptr<T> &lhs,
       const persistent_pool_ptr<Y> &rhs) noexcept
{
    return !(lhs == rhs);
}
 
template <typename T>
inline bool
operator!=(const persistent_pool_ptr<T> &lhs, std::nullptr_t) noexcept
{
    return lhs.raw() != 0;
}
 
template <typename T>
inline bool
operator!=(std::nullptr_t, const persistent_pool_ptr<T> &lhs) noexcept
{
    return lhs.raw() != 0;
}
 
template <typename T>
inline bool
operator==(const persistent_pool_ptr<T> &lhs, std::nullptr_t) noexcept
{
    return lhs.raw() == 0;
}
 
template <typename T>
inline bool
operator==(std::nullptr_t, const persistent_pool_ptr<T> &lhs) noexcept
{
    return lhs.raw() == 0;
}
 
template <class T, class U>
persistent_pool_ptr<T>
static_persistent_pool_pointer_cast(const persistent_pool_ptr<U> &r)
{
    static_assert(std::is_convertible<T *, U *>::value,
              "Cannot cast persistent_pool_ptr");
    return persistent_pool_ptr<T>(r.raw());
}
 
} // namespace detail
} // namespace pmem
 
#endif // PMEMOBJ_PERSISTENT_POOL_PTR_HPP