defrag.hpp

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// SPDX-License-Identifier: BSD-3-Clause
/* Copyright 2020, Intel Corporation */
 
#ifndef LIBPMEMOBJ_CPP_DEFRAG_HPP
#define LIBPMEMOBJ_CPP_DEFRAG_HPP
 
#include <type_traits>
#include <vector>
 
#include <libpmemobj++/detail/template_helpers.hpp>
#include <libpmemobj++/persistent_ptr_base.hpp>
#include <libpmemobj++/pool.hpp>
#include <libpmemobj/atomic_base.h>
#include <libpmemobj/base.h>
 
namespace pmem
{
 
namespace detail
{
using for_each_ptr_function = void (*)(obj::persistent_ptr_base &ptr);
 
template <typename T>
using t_has_for_each_ptr = typename std::enable_if<
    std::is_same<decltype(std::declval<T>().for_each_ptr(
                 std::declval<for_each_ptr_function>())),
             void>::value>::type;
 
template <typename T>
using t_is_defragmentable = supports<T, t_has_for_each_ptr>;
}
 
namespace obj
{
template <typename T>
static constexpr typename std::enable_if<detail::t_is_defragmentable<T>::value,
                     bool>::type
is_defragmentable() noexcept
{
    return true;
}
 
template <typename T>
static constexpr typename std::enable_if<!detail::t_is_defragmentable<T>::value,
                     bool>::type
is_defragmentable() noexcept
{
    return false;
}
 
class defrag {
public:
    defrag(pool_base p)
    {
        this->pop = p;
    }
 
    template <typename T>
    typename std::enable_if<is_defragmentable<T>(), void>::type
    add(T &t)
    {
        if (pmemobj_pool_by_ptr(&t) != pop.handle())
            throw std::runtime_error(
                "object is not from the chosen pool");
 
        t.for_each_ptr([&](persistent_ptr_base &ptr) {
            this->container.push_back(&ptr);
        });
    }
 
    template <typename T, typename = T>
    typename std::enable_if<!is_defragmentable<T>(), void>::type
    add(T &t)
    {
        if (pmemobj_pool_by_ptr(&t) != pop.handle())
            throw std::runtime_error(
                "object is not from the chosen pool");
    }
 
    template <typename T>
    void
    add(persistent_ptr<T> &ptr)
    {
        if (pmemobj_pool_by_oid(ptr.raw()) != pop.handle())
            throw std::runtime_error(
                "persistent_ptr does not point to an object from the chosen pool");
 
        this->container.push_back(&ptr);
        /* Calls 'add(T &)' passing the underlying object (T) */
        this->add<T>(*ptr);
    }
 
    pobj_defrag_result
    run()
    {
        pobj_defrag_result result = this->pop.defrag(
            this->container.data(), this->container.size());
 
        return result;
    }
 
private:
    std::vector<persistent_ptr_base *> container;
    pool_base pop;
};
 
} /* namespace obj */
 
} /* namespace pmem */
 
#endif /* LIBPMEMOBJ_CPP_DEFRAG_HPP */