make_persistent_array.hpp

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/*
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 *
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 *       notice, this list of conditions and the following disclaimer in
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#ifndef LIBPMEMOBJ_CPP_MAKE_PERSISTENT_ARRAY_HPP
#define LIBPMEMOBJ_CPP_MAKE_PERSISTENT_ARRAY_HPP

#include <libpmemobj++/allocation_flag.hpp>
#include <libpmemobj++/detail/array_traits.hpp>
#include <libpmemobj++/detail/check_persistent_ptr_array.hpp>
#include <libpmemobj++/detail/common.hpp>
#include <libpmemobj++/detail/life.hpp>
#include <libpmemobj++/detail/pexceptions.hpp>
#include <libpmemobj++/detail/variadic.hpp>
#include <libpmemobj/tx_base.h>

#include <cassert>
#include <limits>

namespace pmem
{

namespace obj
{

template <typename T>
typename detail::pp_if_array<T>::type
make_persistent(std::size_t N, allocation_flag flag = allocation_flag::none())
{
    typedef typename detail::pp_array_type<T>::type I;

    /*
     * Allowing N greater than ptrdiff_t max value would cause problems
     * with accessing array and calculating address difference between two
     * elements placed further apart than ptrdiff_t max value
     */
    assert(N <=
           static_cast<std::size_t>(std::numeric_limits<ptrdiff_t>::max()));

    if (pmemobj_tx_stage() != TX_STAGE_WORK)
        throw transaction_scope_error(
            "refusing to allocate memory outside of transaction scope");

    persistent_ptr<T> ptr = pmemobj_tx_xalloc(
        sizeof(I) * N, detail::type_num<I>(), flag.value);

    if (ptr == nullptr)
        throw transaction_alloc_error(
            "failed to allocate persistent memory array");

    /*
     * cache raw pointer to data - using persistent_ptr.get() in a loop
     * is expensive.
     */
    auto data = ptr.get();

    /*
     * When an exception is thrown from one of the constructors
     * we don't perform any cleanup - i.e. we don't call destructors
     * (unlike new[] operator), we only rely on transaction abort.
     * This approach was taken to ensure consistent behaviour for
     * case when transaction is aborted after make_persistent completes and
     * we have no way to call destructors.
     */
    for (std::ptrdiff_t i = 0; i < static_cast<std::ptrdiff_t>(N); ++i)
        detail::create<I>(data + i);

    return ptr;
}

template <typename T>
typename detail::pp_if_size_array<T>::type
make_persistent(allocation_flag flag = allocation_flag::none())
{
    typedef typename detail::pp_array_type<T>::type I;
    enum { N = detail::pp_array_elems<T>::elems };

    if (pmemobj_tx_stage() != TX_STAGE_WORK)
        throw transaction_scope_error(
            "refusing to allocate memory outside of transaction scope");

    persistent_ptr<T> ptr = pmemobj_tx_xalloc(
        sizeof(I) * N, detail::type_num<I>(), flag.value);

    if (ptr == nullptr)
        throw transaction_alloc_error(
            "failed to allocate persistent memory array");

    /*
     * cache raw pointer to data - using persistent_ptr.get() in a loop
     * is expensive.
     */
    auto data = ptr.get();

    /*
     * When an exception is thrown from one of the constructors
     * we don't perform any cleanup - i.e. we don't call destructors
     * (unlike new[] operator), we only rely on transaction abort.
     * This approach was taken to ensure consistent behaviour for
     * case when transaction is aborted after make_persistent completes and
     * we have no way to call destructors.
     */
    for (std::ptrdiff_t i = 0; i < static_cast<std::ptrdiff_t>(N); ++i)
        detail::create<I>(data + i);

    return ptr;
}

template <typename T>
void
delete_persistent(typename detail::pp_if_array<T>::type ptr, std::size_t N)
{
    typedef typename detail::pp_array_type<T>::type I;

    if (pmemobj_tx_stage() != TX_STAGE_WORK)
        throw transaction_scope_error(
            "refusing to free memory outside of transaction scope");

    if (ptr == nullptr)
        return;

    /*
     * cache raw pointer to data - using persistent_ptr.get() in a loop
     * is expensive.
     */
    auto data = ptr.get();

    for (std::ptrdiff_t i = 0; i < static_cast<std::ptrdiff_t>(N); ++i)
        detail::destroy<I>(
            data[static_cast<std::ptrdiff_t>(N) - 1 - i]);

    if (pmemobj_tx_free(*ptr.raw_ptr()) != 0)
        throw transaction_free_error(
            "failed to delete persistent memory object");
}

template <typename T>
void
delete_persistent(typename detail::pp_if_size_array<T>::type ptr)
{
    typedef typename detail::pp_array_type<T>::type I;
    enum { N = detail::pp_array_elems<T>::elems };

    if (pmemobj_tx_stage() != TX_STAGE_WORK)
        throw transaction_scope_error(
            "refusing to free memory outside of transaction scope");

    if (ptr == nullptr)
        return;

    /*
     * cache raw pointer to data - using persistent_ptr.get() in a loop
     * is expensive.
     */
    auto data = ptr.get();

    for (std::ptrdiff_t i = 0; i < static_cast<std::ptrdiff_t>(N); ++i)
        detail::destroy<I>(
            data[static_cast<std::ptrdiff_t>(N) - 1 - i]);

    if (pmemobj_tx_free(*ptr.raw_ptr()) != 0)
        throw transaction_free_error(
            "failed to delete persistent memory object");
}

} /* namespace obj */

} /* namespace pmem */

#endif /* LIBPMEMOBJ_CPP_MAKE_PERSISTENT_ARRAY_HPP */