persistent_ptr.hpp

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/*
 * Copyright 2015-2019, Intel Corporation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       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
 *       the documentation and/or other materials provided with the
 *       distribution.
 *
 *     * Neither the name of the copyright holder nor the names of its
 *       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_PERSISTENT_PTR_HPP
#define LIBPMEMOBJ_CPP_PERSISTENT_PTR_HPP
 
#include <cassert>
#include <limits>
#include <memory>
#include <ostream>
 
#include <libpmemobj++/detail/common.hpp>
#include <libpmemobj++/detail/persistent_ptr_base.hpp>
#include <libpmemobj++/detail/specialization.hpp>
#include <libpmemobj++/pool.hpp>
#include <libpmemobj.h>
 
namespace pmem
{
 
namespace obj
{
 
template <typename T>
class pool;
 
template <typename T>
class persistent_ptr;
 
/*
 * persistent_ptr void specialization.
 */
template <>
class persistent_ptr<void> : public detail::persistent_ptr_base<void> {
public:
    persistent_ptr() = default;
    using detail::persistent_ptr_base<void>::persistent_ptr_base;
    using detail::persistent_ptr_base<void>::operator=;
};
 
/*
 * persistent_ptr const void specialization.
 */
template <>
class persistent_ptr<const void>
    : public detail::persistent_ptr_base<const void> {
public:
    persistent_ptr() = default;
    using detail::persistent_ptr_base<const void>::persistent_ptr_base;
    using detail::persistent_ptr_base<const void>::operator=;
};
 
template <typename T>
class persistent_ptr : public detail::persistent_ptr_base<T> {
public:
    persistent_ptr() = default;
    using detail::persistent_ptr_base<T>::persistent_ptr_base;
 
    explicit persistent_ptr(persistent_ptr<void> const &rhs) noexcept
        : detail::persistent_ptr_base<T>(rhs.raw())
    {
    }
 
    explicit persistent_ptr(persistent_ptr<const void> const &rhs) noexcept
        : detail::persistent_ptr_base<T>(rhs.raw())
    {
    }
 
    operator persistent_ptr<void>() const noexcept
    {
        return this->get();
    }
 
    typename pmem::detail::sp_dereference<T>::type operator*() const
        noexcept
    {
        return *this->get();
    }
 
    typename pmem::detail::sp_member_access<T>::type operator->() const
        noexcept
    {
        return this->get();
    }
 
    template <typename = typename std::enable_if<!std::is_void<T>::value>>
    typename pmem::detail::sp_array_access<T>::type
    operator[](std::ptrdiff_t i) const noexcept
    {
        assert(i >= 0 &&
               (i < pmem::detail::sp_extent<T>::value ||
            pmem::detail::sp_extent<T>::value == 0) &&
               "persistent array index out of bounds");
 
        return this->get()[i];
    }
 
    inline persistent_ptr<T> &
    operator++()
    {
        detail::conditional_add_to_tx(this);
        this->oid.off += sizeof(T);
 
        return *this;
    }
 
    inline persistent_ptr<T>
    operator++(int)
    {
        PMEMoid noid = this->oid;
        ++(*this);
 
        return persistent_ptr<T>(noid);
    }
 
    inline persistent_ptr<T> &
    operator--()
    {
        detail::conditional_add_to_tx(this);
        this->oid.off -= sizeof(T);
 
        return *this;
    }
 
    inline persistent_ptr<T>
    operator--(int)
    {
        PMEMoid noid = this->oid;
        --(*this);
 
        return persistent_ptr<T>(noid);
    }
 
    inline persistent_ptr<T> &
    operator+=(std::ptrdiff_t s)
    {
        detail::conditional_add_to_tx(this);
        this->oid.off += static_cast<std::uint64_t>(s) * sizeof(T);
 
        return *this;
    }
 
    inline persistent_ptr<T> &
    operator-=(std::ptrdiff_t s)
    {
        detail::conditional_add_to_tx(this);
        this->oid.off -= static_cast<std::uint64_t>(s) * sizeof(T);
 
        return *this;
    }
 
    void
    persist(pool_base &pop)
    {
        pop.persist(this->get(), sizeof(T));
    }
 
    void
    persist(void)
    {
        pmemobjpool *pop = pmemobj_pool_by_oid(this->raw());
 
        if (pop == nullptr)
            throw pool_error(
                "Cannot get pool from persistent pointer");
 
        pmemobj_persist(pop, this->get(), sizeof(T));
    }
 
    void
    flush(pool_base &pop)
    {
        pop.flush(this->get(), sizeof(T));
    }
 
    void
    flush(void)
    {
        pmemobjpool *pop = pmemobj_pool_by_oid(this->raw());
 
        if (pop == nullptr)
            throw pool_error(
                "Cannot get pool from persistent pointer");
 
        pmemobj_flush(pop, this->get(), sizeof(T));
    }
 
    /*
     * Pointer traits related.
     */
 
    static persistent_ptr<T>
    pointer_to(T &ref)
    {
        return persistent_ptr<T>(std::addressof(ref), 0);
    }
 
    template <class U>
    using rebind = pmem::obj::persistent_ptr<U>;
 
    using persistency_type = p<T>;
 
    using bool_type = bool;
 
    /*
     * Random access iterator requirements (members)
     */
 
    using iterator_category = std::random_access_iterator_tag;
 
    using difference_type = std::ptrdiff_t;
 
    using value_type = T;
 
    using reference = T &;
 
    using pointer = persistent_ptr<T>;
};
 
template <class T>
inline void
swap(persistent_ptr<T> &a, persistent_ptr<T> &b)
{
    a.swap(b);
}
 
template <typename T, typename Y>
inline bool
operator==(persistent_ptr<T> const &lhs, persistent_ptr<Y> const &rhs) noexcept
{
    return OID_EQUALS(lhs.raw(), rhs.raw());
}
 
template <typename T, typename Y>
inline bool
operator!=(persistent_ptr<T> const &lhs, persistent_ptr<Y> const &rhs) noexcept
{
    return !(lhs == rhs);
}
 
template <typename T>
inline bool
operator==(persistent_ptr<T> const &lhs, std::nullptr_t) noexcept
{
    return lhs.get() == nullptr;
}
 
template <typename T>
inline bool
operator==(std::nullptr_t, persistent_ptr<T> const &lhs) noexcept
{
    return lhs.get() == nullptr;
}
 
template <typename T>
inline bool
operator!=(persistent_ptr<T> const &lhs, std::nullptr_t) noexcept
{
    return lhs.get() != nullptr;
}
 
template <typename T>
inline bool
operator!=(std::nullptr_t, persistent_ptr<T> const &lhs) noexcept
{
    return lhs.get() != nullptr;
}
 
template <typename T, typename Y>
inline bool
operator<(persistent_ptr<T> const &lhs, persistent_ptr<Y> const &rhs) noexcept
{
    if (lhs.raw().pool_uuid_lo == rhs.raw().pool_uuid_lo)
        return lhs.raw().off < rhs.raw().off;
    else
        return lhs.raw().pool_uuid_lo < rhs.raw().pool_uuid_lo;
}
 
template <typename T, typename Y>
inline bool
operator<=(persistent_ptr<T> const &lhs, persistent_ptr<Y> const &rhs) noexcept
{
    return !(rhs < lhs);
}
 
template <typename T, typename Y>
inline bool
operator>(persistent_ptr<T> const &lhs, persistent_ptr<Y> const &rhs) noexcept
{
    return (rhs < lhs);
}
 
template <typename T, typename Y>
inline bool
operator>=(persistent_ptr<T> const &lhs, persistent_ptr<Y> const &rhs) noexcept
{
    return !(lhs < rhs);
}
 
/* nullptr comparisons */
 
template <typename T>
inline bool
operator<(persistent_ptr<T> const &lhs, std::nullptr_t) noexcept
{
    return std::less<typename persistent_ptr<T>::element_type *>()(
        lhs.get(), nullptr);
}
 
template <typename T>
inline bool
operator<(std::nullptr_t, persistent_ptr<T> const &rhs) noexcept
{
    return std::less<typename persistent_ptr<T>::element_type *>()(
        nullptr, rhs.get());
}
 
template <typename T>
inline bool
operator<=(persistent_ptr<T> const &lhs, std::nullptr_t) noexcept
{
    return !(nullptr < lhs);
}
 
template <typename T>
inline bool
operator<=(std::nullptr_t, persistent_ptr<T> const &rhs) noexcept
{
    return !(rhs < nullptr);
}
 
template <typename T>
inline bool
operator>(persistent_ptr<T> const &lhs, std::nullptr_t) noexcept
{
    return nullptr < lhs;
}
 
template <typename T>
inline bool
operator>(std::nullptr_t, persistent_ptr<T> const &rhs) noexcept
{
    return rhs < nullptr;
}
 
template <typename T>
inline bool
operator>=(persistent_ptr<T> const &lhs, std::nullptr_t) noexcept
{
    return !(lhs < nullptr);
}
 
template <typename T>
inline bool
operator>=(std::nullptr_t, persistent_ptr<T> const &rhs) noexcept
{
    return !(nullptr < rhs);
}
 
template <typename T>
inline persistent_ptr<T>
operator+(persistent_ptr<T> const &lhs, std::ptrdiff_t s)
{
    PMEMoid noid;
    noid.pool_uuid_lo = lhs.raw().pool_uuid_lo;
    noid.off = lhs.raw().off + static_cast<std::uint64_t>(s) * sizeof(T);
 
    return persistent_ptr<T>(noid);
}
 
template <typename T>
inline persistent_ptr<T>
operator-(persistent_ptr<T> const &lhs, std::ptrdiff_t s)
{
    PMEMoid noid;
    noid.pool_uuid_lo = lhs.raw().pool_uuid_lo;
    noid.off = lhs.raw().off - static_cast<std::uint64_t>(s) * sizeof(T);
 
    return persistent_ptr<T>(noid);
}
 
template <typename T, typename Y,
      typename = typename std::enable_if<
          std::is_same<typename std::remove_cv<T>::type,
                   typename std::remove_cv<Y>::type>::value>>
inline ptrdiff_t
operator-(persistent_ptr<T> const &lhs, persistent_ptr<Y> const &rhs)
{
    assert(lhs.raw().pool_uuid_lo == rhs.raw().pool_uuid_lo);
    auto d = static_cast<std::ptrdiff_t>(lhs.raw().off - rhs.raw().off);
 
    return d / static_cast<std::ptrdiff_t>(sizeof(T));
}
 
template <typename T>
std::ostream &
operator<<(std::ostream &os, persistent_ptr<T> const &pptr)
{
    PMEMoid raw_oid = pptr.raw();
    os << std::hex << "0x" << raw_oid.pool_uuid_lo << ", 0x" << raw_oid.off
       << std::dec;
    return os;
}
 
} /* namespace obj */
 
} /* namespace pmem */
 
#endif /* LIBPMEMOBJ_CPP_PERSISTENT_PTR_HPP */