make_persistent_array.hpp

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// SPDX-License-Identifier: BSD-3-Clause
/* Copyright 2016-2021, Intel Corporation */
 
#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/variadic.hpp>
#include <libpmemobj++/pexceptions.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 pmem::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) {
        const char *msg = "Failed to allocate persistent memory array";
        if (errno == ENOMEM)
            throw detail::exception_with_errormsg<
                pmem::transaction_out_of_memory>(msg);
        else
            throw detail::exception_with_errormsg<
                pmem::transaction_alloc_error>(msg);
    }
 
    /*
     * 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 pmem::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) {
        const char *msg = "Failed to allocate persistent memory array";
        if (errno == ENOMEM)
            throw detail::exception_with_errormsg<
                pmem::transaction_out_of_memory>(msg);
        else
            throw detail::exception_with_errormsg<
                pmem::transaction_alloc_error>(msg);
    }
 
    /*
     * 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 pmem::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 detail::exception_with_errormsg<
            pmem::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 pmem::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 detail::exception_with_errormsg<
            pmem::transaction_free_error>(
            "failed to delete persistent memory object");
}
 
} /* namespace obj */
 
} /* namespace pmem */
 
#endif /* LIBPMEMOBJ_CPP_MAKE_PERSISTENT_ARRAY_HPP */