rippled/include/xrpl/beast/container/detail/aged_ordered_container.h

#pragma once

#include <xrpl/beast/clock/abstract_clock.h>
#include <xrpl/beast/container/aged_container.h>
#include <xrpl/beast/container/detail/aged_associative_container.h>
#include <xrpl/beast/container/detail/aged_container_iterator.h>
#include <xrpl/beast/container/detail/empty_base_optimization.h>

#include <boost/intrusive/list.hpp>
#include <boost/intrusive/set.hpp>
#include <boost/version.hpp>

#include <algorithm>
#include <chrono>
#include <cstddef>
#include <cstdint>
#include <functional>
#include <initializer_list>
#include <memory>
#include <stdexcept>
#include <tuple>
#include <type_traits>
#include <utility>

namespace beast {
namespace detail {

// Traits templates used to discern reverse_iterators, which are disallowed
// for mutating operations.
template <class It>
struct IsBoostReverseIterator : std::false_type
{
    explicit IsBoostReverseIterator() = default;
};

template <class It>
struct IsBoostReverseIterator<boost::intrusive::reverse_iterator<It>> : std::true_type
{
    explicit IsBoostReverseIterator() = default;
};

/**
 * Associative container where each element is also indexed by time.
 *
 * This container mirrors the interface of the standard library ordered
 * associative containers, with the addition that each element is associated
 * with a `when` `time_point` which is obtained from the value of the clock's
 * `now`. The function `touch` updates the time for an element to the current
 * time as reported by the clock.
 *
 * An extra set of iterator types and member functions are provided in the
 * `chronological` memberspace that allow traversal in temporal or reverse
 * temporal order. This container is useful as a building block for caches
 * whose items expire after a certain amount of time. The chronological
 * iterators allow for fully customizable expiration strategies.
 *
 * @see aged_set, aged_multiset, aged_map, aged_multimap
 */
template <
    bool IsMulti,
    bool IsMap,
    class Key,
    class T,
    class Clock = std::chrono::steady_clock,
    class Compare = std::less<Key>,
    class Allocator = std::allocator<std::conditional_t<IsMap, std::pair<Key const, T>, Key>>>
class AgedOrderedContainer
{
public:
    using clock_type = AbstractClock<Clock>;
    using time_point = clock_type::time_point;
    using duration = clock_type::duration;
    using key_type = Key;
    using mapped_type = T;
    using value_type = std::conditional_t<IsMap, std::pair<Key const, T>, Key>;
    using size_type = std::size_t;
    using difference_type = std::ptrdiff_t;

    // Introspection (for unit tests)
    using is_unordered = std::false_type;
    using is_multi = std::integral_constant<bool, IsMulti>;
    using is_map = std::integral_constant<bool, IsMap>;

private:
    static Key const&
    extract(value_type const& value)
    {
        return AgedAssociativeContainerExtractT<IsMap>()(value);
    }

    // VFALCO TODO hoist to remove template argument dependencies
    struct Element : boost::intrusive::set_base_hook<
                         boost::intrusive::link_mode<boost::intrusive::normal_link>>,
                     boost::intrusive::list_base_hook<
                         boost::intrusive::link_mode<boost::intrusive::normal_link>>
    {
        // Stash types here so the iterator doesn't
        // need to see the container declaration.
        struct Stashed
        {
            explicit Stashed() = default;

            using value_type = AgedOrderedContainer::value_type;
            using time_point = AgedOrderedContainer::time_point;
        };

        Element(time_point const& when, value_type const& value) : value(value), when(when)
        {
        }

        Element(time_point const& when, value_type&& value) : value(std::move(value)), when(when)
        {
        }

        template <class... Args>
        Element(time_point const& when, Args&&... args)
            requires(std::is_constructible_v<value_type, Args...>)
            : value(std::forward<Args>(args)...), when(when)
        {
        }

        value_type value;
        time_point when;
    };

    // VFALCO TODO This should only be enabled for maps.
    class PairValueCompare : public Compare
    {
    public:
        using first_argument = value_type;
        using second_argument = value_type;
        using result_type = bool;

        bool
        operator()(value_type const& lhs, value_type const& rhs) const
        {
            return Compare::operator()(lhs.first, rhs.first);
        }

        PairValueCompare() = default;

        PairValueCompare(PairValueCompare const& other) : Compare(other)
        {
        }

    private:
        friend AgedOrderedContainer;

        PairValueCompare(Compare const& compare) : Compare(compare)
        {
        }
    };

    // Compares value_type against element, used in insert_check
    // VFALCO TODO hoist to remove template argument dependencies
    class KeyValueCompare : public Compare
    {
    public:
        using first_argument = Key;
        using second_argument = Element;
        using result_type = bool;

        KeyValueCompare() = default;

        KeyValueCompare(Compare const& compare) : Compare(compare)
        {
        }

        bool
        operator()(Key const& k, Element const& e) const
        {
            return Compare::operator()(k, extract(e.value));
        }

        bool
        operator()(Element const& e, Key const& k) const
        {
            return Compare::operator()(extract(e.value), k);
        }

        bool
        operator()(Element const& x, Element const& y) const
        {
            return Compare::operator()(extract(x.value), extract(y.value));
        }

        Compare&
        compare()
        {
            return *this;
        }

        [[nodiscard]] Compare const&
        compare() const
        {
            return *this;
        }
    };

    using list_type =
        boost::intrusive::make_list<Element, boost::intrusive::constant_time_size<false>>::type;

    using cont_type = std::conditional_t<
        IsMulti,
        typename boost::intrusive::make_multiset<
            Element,
            boost::intrusive::constant_time_size<true>,
            boost::intrusive::compare<KeyValueCompare>>::type,
        typename boost::intrusive::make_set<
            Element,
            boost::intrusive::constant_time_size<true>,
            boost::intrusive::compare<KeyValueCompare>>::type>;

    using ElementAllocator = std::allocator_traits<Allocator>::template rebind_alloc<Element>;

    using ElementAllocatorTraits = std::allocator_traits<ElementAllocator>;

    class ConfigT : private KeyValueCompare,
                    public beast::detail::EmptyBaseOptimization<ElementAllocator>
    {
    public:
        explicit ConfigT(clock_type& clock) : clock(clock)
        {
        }

        ConfigT(clock_type& clock, Compare const& comp) : KeyValueCompare(comp), clock(clock)
        {
        }

        ConfigT(clock_type& clock, Allocator const& alloc)
            : beast::detail::EmptyBaseOptimization<ElementAllocator>(alloc), clock(clock)
        {
        }

        ConfigT(clock_type& clock, Compare const& comp, Allocator const& alloc)
            : KeyValueCompare(comp)
            , beast::detail::EmptyBaseOptimization<ElementAllocator>(alloc)
            , clock(clock)
        {
        }

        ConfigT(ConfigT const& other)
            : KeyValueCompare(other.keyCompare())
            , beast::detail::EmptyBaseOptimization<ElementAllocator>(
                  ElementAllocatorTraits::select_on_container_copy_construction(other.alloc()))
            , clock(other.clock)
        {
        }

        ConfigT(ConfigT const& other, Allocator const& alloc)
            : KeyValueCompare(other.keyCompare())
            , beast::detail::EmptyBaseOptimization<ElementAllocator>(alloc)
            , clock(other.clock)
        {
        }

        ConfigT(ConfigT&& other)
            : KeyValueCompare(std::move(other.keyCompare()))
            , beast::detail::EmptyBaseOptimization<ElementAllocator>(std::move(
                  static_cast<beast::detail::EmptyBaseOptimization<ElementAllocator>&>(other)))
            , clock(other.clock)
        {
        }

        ConfigT(
            ConfigT&& other,  // NOLINT(cppcoreguidelines-rvalue-reference-param-not-moved)
            Allocator const& alloc)
            : KeyValueCompare(std::move(other.keyCompare()))
            , beast::detail::EmptyBaseOptimization<ElementAllocator>(alloc)
            , clock(other.clock)
        {
        }

        ConfigT&
        operator=(ConfigT const& other)
        {
            if (this != &other)
            {
                compare() = other.compare();
                alloc() = other.alloc();
                clock = other.clock;
            }
            return *this;
        }

        ConfigT&
        operator=(ConfigT&& other)
        {
            compare() = std::move(other.compare());
            alloc() = std::move(other.alloc());
            clock = other.clock;
            return *this;
        }

        Compare&
        compare()
        {
            return KeyValueCompare::compare();
        }

        [[nodiscard]] Compare const&
        compare() const
        {
            return KeyValueCompare::compare();
        }

        KeyValueCompare&
        keyCompare()
        {
            return *this;
        }

        [[nodiscard]] KeyValueCompare const&
        keyCompare() const
        {
            return *this;
        }

        ElementAllocator&
        alloc()
        {
            return beast::detail::EmptyBaseOptimization<ElementAllocator>::member();
        }

        [[nodiscard]] ElementAllocator const&
        alloc() const
        {
            return beast::detail::EmptyBaseOptimization<ElementAllocator>::member();
        }

        std::reference_wrapper<clock_type> clock;
    };

    template <class... Args>
    Element*
    newElement(Args&&... args)
    {
        struct Deleter
        {
            std::reference_wrapper<ElementAllocator> a;
            Deleter(ElementAllocator& a) : a(a)
            {
            }

            void
            operator()(Element* p)
            {
                ElementAllocatorTraits::deallocate(a.get(), p, 1);
            }
        };

        std::unique_ptr<Element, Deleter> p(
            ElementAllocatorTraits::allocate(config_.alloc(), 1), Deleter(config_.alloc()));
        ElementAllocatorTraits::construct(
            config_.alloc(), p.get(), clock().now(), std::forward<Args>(args)...);
        return p.release();
    }

    void
    deleteElement(Element const* p)
    {
        ElementAllocatorTraits::destroy(config_.alloc(), p);
        // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)
        ElementAllocatorTraits::deallocate(config_.alloc(), const_cast<Element*>(p), 1);
    }

    void
    unlinkAndDeleteElement(Element const* p)
    {
        chronological.list_.erase(chronological.list_.iterator_to(*p));
        cont_.erase(cont_.iterator_to(*p));
        deleteElement(p);
    }

public:
    using key_compare = Compare;
    using value_compare = std::conditional_t<IsMap, PairValueCompare, Compare>;
    using allocator_type = Allocator;
    using reference = value_type&;
    using const_reference = value_type const&;
    using pointer = std::allocator_traits<Allocator>::pointer;
    using const_pointer = std::allocator_traits<Allocator>::const_pointer;

    // A set iterator (IsMap==false) is always const
    // because the elements of a set are immutable.
    using iterator = beast::detail::AgedContainerIterator<!IsMap, typename cont_type::iterator>;
    using const_iterator = beast::detail::AgedContainerIterator<true, typename cont_type::iterator>;
    using reverse_iterator =
        beast::detail::AgedContainerIterator<!IsMap, typename cont_type::reverse_iterator>;
    using const_reverse_iterator =
        beast::detail::AgedContainerIterator<true, typename cont_type::reverse_iterator>;

    //--------------------------------------------------------------------------
    //
    // Chronological ordered iterators
    //
    // "Memberspace"
    // http://accu.org/index.php/journals/1527
    //
    //--------------------------------------------------------------------------

    class ChronologicalT
    {
        ChronologicalT() = default;

    public:
        // A set iterator (IsMap==false) is always const
        // because the elements of a set are immutable.
        using iterator = beast::detail::AgedContainerIterator<!IsMap, typename list_type::iterator>;
        using const_iterator =
            beast::detail::AgedContainerIterator<true, typename list_type::iterator>;
        using reverse_iterator =
            beast::detail::AgedContainerIterator<!IsMap, typename list_type::reverse_iterator>;
        using const_reverse_iterator =
            beast::detail::AgedContainerIterator<true, typename list_type::reverse_iterator>;

        iterator
        begin()
        {
            return iterator(list_.begin());
        }

        const_iterator
        begin() const
        {
            return const_iterator(list_.begin());
        }

        const_iterator
        cbegin() const
        {
            return const_iterator(list_.begin());
        }

        iterator
        end()
        {
            return iterator(list_.end());
        }

        const_iterator
        end() const
        {
            return const_iterator(list_.end());
        }

        const_iterator
        cend() const
        {
            return const_iterator(list_.end());
        }

        reverse_iterator
        rbegin()
        {
            return reverse_iterator(list_.rbegin());
        }

        const_reverse_iterator
        rbegin() const
        {
            return const_reverse_iterator(list_.rbegin());
        }

        const_reverse_iterator
        crbegin() const
        {
            return const_reverse_iterator(list_.rbegin());
        }

        reverse_iterator
        rend()
        {
            return reverse_iterator(list_.rend());
        }

        const_reverse_iterator
        rend() const
        {
            return const_reverse_iterator(list_.rend());
        }

        const_reverse_iterator
        crend() const
        {
            return const_reverse_iterator(list_.rend());
        }

        iterator
        iteratorTo(value_type& value)
        {
            static_assert(std::is_standard_layout_v<Element>, "must be standard layout");
            return list_.iterator_to(*reinterpret_cast<Element*>(
                reinterpret_cast<uint8_t*>(&value) -
                ((std::size_t)std::addressof(((Element*)0)->member))));
        }

        const_iterator
        iteratorTo(value_type const& value) const
        {
            static_assert(std::is_standard_layout_v<Element>, "must be standard layout");
            return list_.iterator_to(*reinterpret_cast<Element const*>(
                reinterpret_cast<uint8_t const*>(&value) -
                ((std::size_t)std::addressof(((Element*)0)->member))));
        }

        ChronologicalT(ChronologicalT const&) = delete;
        ChronologicalT(ChronologicalT&&) = delete;

    private:
        friend class AgedOrderedContainer;
        list_type mutable list_;
    } chronological;

    //--------------------------------------------------------------------------
    //
    // Construction
    //
    //--------------------------------------------------------------------------

    AgedOrderedContainer() = delete;

    explicit AgedOrderedContainer(clock_type& clock);

    AgedOrderedContainer(clock_type& clock, Compare const& comp);

    AgedOrderedContainer(clock_type& clock, Allocator const& alloc);

    AgedOrderedContainer(clock_type& clock, Compare const& comp, Allocator const& alloc);

    template <class InputIt>
    AgedOrderedContainer(InputIt first, InputIt last, clock_type& clock);

    template <class InputIt>
    AgedOrderedContainer(InputIt first, InputIt last, clock_type& clock, Compare const& comp);

    template <class InputIt>
    AgedOrderedContainer(InputIt first, InputIt last, clock_type& clock, Allocator const& alloc);

    template <class InputIt>
    AgedOrderedContainer(
        InputIt first,
        InputIt last,
        clock_type& clock,
        Compare const& comp,
        Allocator const& alloc);

    AgedOrderedContainer(AgedOrderedContainer const& other);

    AgedOrderedContainer(AgedOrderedContainer const& other, Allocator const& alloc);

    AgedOrderedContainer(AgedOrderedContainer&& other);

    AgedOrderedContainer(
        // NOLINTNEXTLINE(cppcoreguidelines-rvalue-reference-param-not-moved)
        AgedOrderedContainer&& other,
        Allocator const& alloc);

    AgedOrderedContainer(std::initializer_list<value_type> init, clock_type& clock);

    AgedOrderedContainer(
        std::initializer_list<value_type> init,
        clock_type& clock,
        Compare const& comp);

    AgedOrderedContainer(
        std::initializer_list<value_type> init,
        clock_type& clock,
        Allocator const& alloc);

    AgedOrderedContainer(
        std::initializer_list<value_type> init,
        clock_type& clock,
        Compare const& comp,
        Allocator const& alloc);

    ~AgedOrderedContainer();

    AgedOrderedContainer&
    operator=(AgedOrderedContainer const& other);

    AgedOrderedContainer&
    operator=(AgedOrderedContainer&& other);

    AgedOrderedContainer&
    operator=(std::initializer_list<value_type> init);

    allocator_type
    getAllocator() const
    {
        return config_.alloc();
    }

    clock_type&
    clock()
    {
        return config_.clock;
    }

    clock_type const&
    clock() const
    {
        return config_.clock;
    }

    //--------------------------------------------------------------------------
    //
    // Element access (maps)
    //
    //--------------------------------------------------------------------------

    template <class K, bool MaybeMulti = IsMulti, bool MaybeMap = IsMap>
    std::conditional_t<IsMap, T, void*>&
    at(K const& k)
        requires(MaybeMap && !MaybeMulti);

    template <class K, bool MaybeMulti = IsMulti, bool MaybeMap = IsMap>
    std::conditional<IsMap, T, void*>::type const&
    at(K const& k) const
        requires(MaybeMap && !MaybeMulti);

    template <bool MaybeMulti = IsMulti, bool MaybeMap = IsMap>
    std::conditional_t<IsMap, T, void*>&
    operator[](Key const& key)
        requires(MaybeMap && !MaybeMulti);

    template <bool MaybeMulti = IsMulti, bool MaybeMap = IsMap>
    std::conditional_t<IsMap, T, void*>&
    operator[](Key&& key)
        requires(MaybeMap && !MaybeMulti);

    //--------------------------------------------------------------------------
    //
    // Iterators
    //
    //--------------------------------------------------------------------------

    iterator
    begin()
    {
        return iterator(cont_.begin());
    }

    const_iterator
    begin() const
    {
        return const_iterator(cont_.begin());
    }

    const_iterator
    cbegin() const
    {
        return const_iterator(cont_.begin());
    }

    iterator
    end()
    {
        return iterator(cont_.end());
    }

    const_iterator
    end() const
    {
        return const_iterator(cont_.end());
    }

    const_iterator
    cend() const
    {
        return const_iterator(cont_.end());
    }

    reverse_iterator
    rbegin()
    {
        return reverse_iterator(cont_.rbegin());
    }

    const_reverse_iterator
    rbegin() const
    {
        return const_reverse_iterator(cont_.rbegin());
    }

    const_reverse_iterator
    crbegin() const
    {
        return const_reverse_iterator(cont_.rbegin());
    }

    reverse_iterator
    rend()
    {
        return reverse_iterator(cont_.rend());
    }

    const_reverse_iterator
    rend() const
    {
        return const_reverse_iterator(cont_.rend());
    }

    const_reverse_iterator
    crend() const
    {
        return const_reverse_iterator(cont_.rend());
    }

    iterator
    iteratorTo(value_type& value)
    {
        static_assert(std::is_standard_layout_v<Element>, "must be standard layout");
        return cont_.iterator_to(*reinterpret_cast<Element*>(
            reinterpret_cast<uint8_t*>(&value) -
            ((std::size_t)std::addressof(((Element*)0)->member))));
    }

    const_iterator
    iteratorTo(value_type const& value) const
    {
        static_assert(std::is_standard_layout_v<Element>, "must be standard layout");
        return cont_.iterator_to(*reinterpret_cast<Element const*>(
            reinterpret_cast<uint8_t const*>(&value) -
            ((std::size_t)std::addressof(((Element*)0)->member))));
    }

    //--------------------------------------------------------------------------
    //
    // Capacity
    //
    //--------------------------------------------------------------------------

    bool
    empty() const noexcept
    {
        return cont_.empty();
    }

    size_type
    size() const noexcept
    {
        return cont_.size();
    }

    size_type
    maxSize() const noexcept
    {
        return config_.max_size();
    }

    //--------------------------------------------------------------------------
    //
    // Modifiers
    //
    //--------------------------------------------------------------------------

    void
    clear();

    // map, set
    template <bool MaybeMulti = IsMulti>
    auto
    insert(value_type const& value) -> std::pair<iterator, bool>
        requires(!MaybeMulti);

    // multimap, multiset
    template <bool MaybeMulti = IsMulti>
    auto
    insert(value_type const& value) -> iterator
        requires MaybeMulti;

    // set
    template <bool MaybeMulti = IsMulti, bool MaybeMap = IsMap>
    auto
    insert(value_type&& value) -> std::pair<iterator, bool>
        requires(!MaybeMulti && !MaybeMap);

    // multiset
    template <bool MaybeMulti = IsMulti, bool MaybeMap = IsMap>
    auto
    insert(value_type&& value) -> iterator
        requires(MaybeMulti && !MaybeMap);

    //---

    // map, set
    template <bool MaybeMulti = IsMulti>
    auto
    insert(const_iterator hint, value_type const& value) -> iterator
        requires(!MaybeMulti);

    // multimap, multiset
    template <bool MaybeMulti = IsMulti>
    iterator
    insert(const_iterator /*hint*/, value_type const& value)
        requires MaybeMulti
    {
        // VFALCO TODO Figure out how to utilize 'hint'
        return insert(value);
    }

    // map, set
    template <bool MaybeMulti = IsMulti>
    auto
    insert(const_iterator hint, value_type&& value) -> iterator
        requires(!MaybeMulti);

    // multimap, multiset
    template <bool MaybeMulti = IsMulti>
    iterator
    insert(const_iterator /*hint*/, value_type&& value)
        requires MaybeMulti
    {
        // VFALCO TODO Figure out how to utilize 'hint'
        return insert(std::move(value));
    }

    // map, multimap
    template <class P, bool MaybeMap = IsMap>
    std::conditional_t<IsMulti, iterator, std::pair<iterator, bool>>
    insert(P&& value)
        requires(MaybeMap && std::is_constructible_v<value_type, P &&>)
    {
        return emplace(std::forward<P>(value));
    }

    // map, multimap
    template <class P, bool MaybeMap = IsMap>
    std::conditional_t<IsMulti, iterator, std::pair<iterator, bool>>
    insert(const_iterator hint, P&& value)
        requires(MaybeMap && std::is_constructible_v<value_type, P &&>)
    {
        return emplaceHint(hint, std::forward<P>(value));
    }

    template <class InputIt>
    void
    insert(InputIt first, InputIt last)
    {
        for (; first != last; ++first)
            insert(cend(), *first);
    }

    void
    insert(std::initializer_list<value_type> init)
    {
        insert(init.begin(), init.end());
    }

    // map, set
    template <bool MaybeMulti = IsMulti, class... Args>
    auto
    emplace(Args&&... args) -> std::pair<iterator, bool>
        requires(!MaybeMulti);

    // multiset, multimap
    template <bool MaybeMulti = IsMulti, class... Args>
    auto
    emplace(Args&&... args) -> iterator
        requires MaybeMulti;

    // map, set
    template <bool MaybeMulti = IsMulti, class... Args>
    auto
    emplaceHint(const_iterator hint, Args&&... args) -> std::pair<iterator, bool>
        requires(!MaybeMulti);

    // multiset, multimap
    template <bool MaybeMulti = IsMulti, class... Args>
    iterator
    emplaceHint(const_iterator /*hint*/, Args&&... args)
        requires MaybeMulti
    {
        // VFALCO TODO Figure out how to utilize 'hint'
        return emplace<MaybeMulti>(std::forward<Args>(args)...);
    }

    // The constraint prevents erase (reverse_iterator pos) from compiling
    template <bool IsConst, class Iterator>
    beast::detail::AgedContainerIterator<false, Iterator>
    erase(beast::detail::AgedContainerIterator<IsConst, Iterator> pos)
        requires(!IsBoostReverseIterator<Iterator>::value);

    // The constraint prevents erase (reverse_iterator first, reverse_iterator last)
    // from compiling
    template <bool IsConst, class Iterator>
    beast::detail::AgedContainerIterator<false, Iterator>
    erase(
        beast::detail::AgedContainerIterator<IsConst, Iterator> first,
        beast::detail::AgedContainerIterator<IsConst, Iterator> last)
        requires(!IsBoostReverseIterator<Iterator>::value);

    template <class K>
    auto
    erase(K const& k) -> size_type;

    void
    swap(AgedOrderedContainer& other) noexcept;

    //--------------------------------------------------------------------------

    // The constraint prevents touch (reverse_iterator pos) from compiling
    template <bool IsConst, class Iterator>
    void
    touch(beast::detail::AgedContainerIterator<IsConst, Iterator> pos)
        requires(!IsBoostReverseIterator<Iterator>::value)
    {
        touch(pos, clock().now());
    }

    template <class K>
    size_type
    touch(K const& k);

    //--------------------------------------------------------------------------
    //
    // Lookup
    //
    //--------------------------------------------------------------------------

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    size_type
    count(K const& k) const
    {
        return cont_.count(k, std::cref(config_.keyCompare()));
    }

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    iterator
    find(K const& k)
    {
        return iterator(cont_.find(k, std::cref(config_.keyCompare())));
    }

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    const_iterator
    find(K const& k) const
    {
        return const_iterator(cont_.find(k, std::cref(config_.keyCompare())));
    }

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    std::pair<iterator, iterator>
    equalRange(K const& k)
    {
        auto const r(cont_.equal_range(k, std::cref(config_.keyCompare())));
        return std::make_pair(iterator(r.first), iterator(r.second));
    }

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    std::pair<const_iterator, const_iterator>
    equalRange(K const& k) const
    {
        auto const r(cont_.equal_range(k, std::cref(config_.keyCompare())));
        return std::make_pair(const_iterator(r.first), const_iterator(r.second));
    }

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    iterator
    lowerBound(K const& k)
    {
        return iterator(cont_.lower_bound(k, std::cref(config_.keyCompare())));
    }

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    const_iterator
    lowerBound(K const& k) const
    {
        return const_iterator(cont_.lower_bound(k, std::cref(config_.keyCompare())));
    }

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    iterator
    upperBound(K const& k)
    {
        return iterator(cont_.upper_bound(k, std::cref(config_.keyCompare())));
    }

    // VFALCO TODO Respect is_transparent (c++14)
    template <class K>
    const_iterator
    upperBound(K const& k) const
    {
        return const_iterator(cont_.upper_bound(k, std::cref(config_.keyCompare())));
    }

    //--------------------------------------------------------------------------
    //
    // Observers
    //
    //--------------------------------------------------------------------------

    key_compare
    keyComp() const
    {
        return config_.compare();
    }

    // VFALCO TODO Should this return const reference for set?
    value_compare
    valueComp() const
    {
        return value_compare(config_.compare());
    }

    //--------------------------------------------------------------------------
    //
    // Comparison
    //
    //--------------------------------------------------------------------------

    // This differs from the standard in that the comparison
    // is only done on the key portion of the value type, ignoring
    // the mapped type.
    //
    template <
        bool OtherIsMulti,
        bool OtherIsMap,
        class OtherT,
        class OtherDuration,
        class OtherAllocator>
    bool
    operator==(AgedOrderedContainer<
               OtherIsMulti,
               OtherIsMap,
               Key,
               OtherT,
               OtherDuration,
               Compare,
               OtherAllocator> const& other) const;

    template <
        bool OtherIsMulti,
        bool OtherIsMap,
        class OtherT,
        class OtherDuration,
        class OtherAllocator>
    bool
    operator!=(AgedOrderedContainer<
               OtherIsMulti,
               OtherIsMap,
               Key,
               OtherT,
               OtherDuration,
               Compare,
               OtherAllocator> const& other) const
    {
        return !(this->operator==(other));
    }

    template <
        bool OtherIsMulti,
        bool OtherIsMap,
        class OtherT,
        class OtherDuration,
        class OtherAllocator>
    bool
    operator<(AgedOrderedContainer<
              OtherIsMulti,
              OtherIsMap,
              Key,
              OtherT,
              OtherDuration,
              Compare,
              OtherAllocator> const& other) const
    {
        value_compare const comp(valueComp());
        return std::lexicographical_compare(cbegin(), cend(), other.cbegin(), other.cend(), comp);
    }

    template <
        bool OtherIsMulti,
        bool OtherIsMap,
        class OtherT,
        class OtherDuration,
        class OtherAllocator>
    bool
    operator<=(AgedOrderedContainer<
               OtherIsMulti,
               OtherIsMap,
               Key,
               OtherT,
               OtherDuration,
               Compare,
               OtherAllocator> const& other) const
    {
        return !(other < *this);
    }

    template <
        bool OtherIsMulti,
        bool OtherIsMap,
        class OtherT,
        class OtherDuration,
        class OtherAllocator>
    bool
    operator>(AgedOrderedContainer<
              OtherIsMulti,
              OtherIsMap,
              Key,
              OtherT,
              OtherDuration,
              Compare,
              OtherAllocator> const& other) const
    {
        return other < *this;
    }

    template <
        bool OtherIsMulti,
        bool OtherIsMap,
        class OtherT,
        class OtherDuration,
        class OtherAllocator>
    bool
    operator>=(AgedOrderedContainer<
               OtherIsMulti,
               OtherIsMap,
               Key,
               OtherT,
               OtherDuration,
               Compare,
               OtherAllocator> const& other) const
    {
        return !(*this < other);
    }

private:
    // The constraint prevents erase (reverse_iterator pos, now) from compiling
    template <bool IsConst, class Iterator>
    void
    touch(
        beast::detail::AgedContainerIterator<IsConst, Iterator> pos,
        clock_type::time_point const& now)
        requires(!IsBoostReverseIterator<Iterator>::value);

    template <
        bool MaybePropagate = std::allocator_traits<Allocator>::propagate_on_container_swap::value>
    void
    swapData(AgedOrderedContainer& other) noexcept
        requires MaybePropagate;

    template <
        bool MaybePropagate = std::allocator_traits<Allocator>::propagate_on_container_swap::value>
    void
    swapData(AgedOrderedContainer& other) noexcept
        requires(!MaybePropagate);

private:
    ConfigT config_;
    cont_type mutable cont_;
};

//------------------------------------------------------------------------------

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    clock_type& clock)
    : config_(clock)
{
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    clock_type& clock,
    Compare const& comp)
    : config_(clock, comp), cont_(comp)
{
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    clock_type& clock,
    Allocator const& alloc)
    : config_(clock, alloc)
{
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    clock_type& clock,
    Compare const& comp,
    Allocator const& alloc)
    : config_(clock, comp, alloc), cont_(comp)
{
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <class InputIt>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    InputIt first,
    InputIt last,
    clock_type& clock)
    : config_(clock)
{
    insert(first, last);
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <class InputIt>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    InputIt first,
    InputIt last,
    clock_type& clock,
    Compare const& comp)
    : config_(clock, comp), cont_(comp)
{
    insert(first, last);
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <class InputIt>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    InputIt first,
    InputIt last,
    clock_type& clock,
    Allocator const& alloc)
    : config_(clock, alloc)
{
    insert(first, last);
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <class InputIt>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    InputIt first,
    InputIt last,
    clock_type& clock,
    Compare const& comp,
    Allocator const& alloc)
    : config_(clock, comp, alloc), cont_(comp)
{
    insert(first, last);
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    AgedOrderedContainer const& other)
    : config_(other.config_), cont_(other.cont_.get_comp())
{
    insert(other.cbegin(), other.cend());
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    AgedOrderedContainer const& other,
    Allocator const& alloc)
    : config_(other.config_, alloc), cont_(other.cont_.get_comp())
{
    insert(other.cbegin(), other.cend());
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    AgedOrderedContainer&& other)
    : config_(std::move(other.config_)), cont_(std::move(other.cont_))
{
    chronological.list_ = std::move(other.chronological.list_);
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    AgedOrderedContainer&& other,  // NOLINT(cppcoreguidelines-rvalue-reference-param-not-moved)
    Allocator const& alloc)
    : config_(std::move(other.config_), alloc), cont_(std::move(other.cont_.get_comp()))
{
    insert(other.cbegin(), other.cend());
    other.clear();
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    std::initializer_list<value_type> init,
    clock_type& clock)
    : config_(clock)
{
    insert(init.begin(), init.end());
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    std::initializer_list<value_type> init,
    clock_type& clock,
    Compare const& comp)
    : config_(clock, comp), cont_(comp)
{
    insert(init.begin(), init.end());
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    std::initializer_list<value_type> init,
    clock_type& clock,
    Allocator const& alloc)
    : config_(clock, alloc)
{
    insert(init.begin(), init.end());
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::AgedOrderedContainer(
    std::initializer_list<value_type> init,
    clock_type& clock,
    Compare const& comp,
    Allocator const& alloc)
    : config_(clock, comp, alloc), cont_(comp)
{
    insert(init.begin(), init.end());
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::~AgedOrderedContainer()
{
    clear();
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::operator=(
    AgedOrderedContainer const& other) -> AgedOrderedContainer&
{
    if (this != &other)
    {
        clear();
        this->config_ = other.config_;
        insert(other.begin(), other.end());
    }
    return *this;
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::operator=(
    AgedOrderedContainer&& other) -> AgedOrderedContainer&
{
    clear();
    this->config_ = std::move(other.config_);
    insert(other.begin(), other.end());
    other.clear();
    return *this;
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::operator=(
    std::initializer_list<value_type> init) -> AgedOrderedContainer&
{
    clear();
    insert(init);
    return *this;
}

//------------------------------------------------------------------------------

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <class K, bool MaybeMulti, bool MaybeMap>
std::conditional_t<IsMap, T, void*>&
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::at(K const& k)
    requires(MaybeMap && !MaybeMulti)
{
    auto const iter(cont_.find(k, std::cref(config_.keyCompare())));
    if (iter == cont_.end())
        throw std::out_of_range("key not found");
    return iter->value.second;
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <class K, bool MaybeMulti, bool MaybeMap>
std::conditional<IsMap, T, void*>::type const&
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::at(K const& k) const
    requires(MaybeMap && !MaybeMulti)
{
    auto const iter(cont_.find(k, std::cref(config_.keyCompare())));
    if (iter == cont_.end())
        throw std::out_of_range("key not found");
    return iter->value.second;
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti, bool MaybeMap>
std::conditional_t<IsMap, T, void*>&
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::operator[](Key const& key)
    requires(MaybeMap && !MaybeMulti)
{
    typename cont_type::insert_commit_data d;
    auto const result(cont_.insert_check(key, std::cref(config_.keyCompare()), d));
    if (result.second)
    {
        Element* const p(newElement(
            std::piecewise_construct, std::forward_as_tuple(key), std::forward_as_tuple()));
        cont_.insert_commit(*p, d);
        chronological.list_.push_back(*p);
        return p->value.second;
    }
    return result.first->value.second;
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti, bool MaybeMap>
std::conditional_t<IsMap, T, void*>&
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::operator[](Key&& key)
    requires(MaybeMap && !MaybeMulti)
{
    typename cont_type::insert_commit_data d;
    auto const result(cont_.insert_check(key, std::cref(config_.keyCompare()), d));
    if (result.second)
    {
        Element* const p(newElement(
            std::piecewise_construct,
            std::forward_as_tuple(std::move(key)),
            std::forward_as_tuple()));
        cont_.insert_commit(*p, d);
        chronological.list_.push_back(*p);
        return p->value.second;
    }
    return result.first->value.second;
}

//------------------------------------------------------------------------------

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
void
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::clear()
{
    for (auto iter(chronological.list_.begin()); iter != chronological.list_.end();)
        deleteElement(&*iter++);
    chronological.list_.clear();
    cont_.clear();
}

// map, set
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::insert(
    value_type const& value) -> std::pair<iterator, bool>
    requires(!MaybeMulti)
{
    typename cont_type::insert_commit_data d;
    auto const result(cont_.insert_check(extract(value), std::cref(config_.keyCompare()), d));
    if (result.second)
    {
        Element* const p(newElement(value));
        auto const iter(cont_.insert_commit(*p, d));
        chronological.list_.push_back(*p);
        return std::make_pair(iterator(iter), true);
    }
    return std::make_pair(iterator(result.first), false);
}

// multimap, multiset
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::insert(
    value_type const& value) -> iterator
    requires MaybeMulti
{
    auto const before(cont_.upper_bound(extract(value), std::cref(config_.keyCompare())));
    Element* const p(newElement(value));
    chronological.list_.push_back(*p);
    auto const iter(cont_.insert_before(before, *p));
    return iterator(iter);
}

// set
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti, bool MaybeMap>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::insert(value_type&& value)
    -> std::pair<iterator, bool>
    requires(!MaybeMulti && !MaybeMap)
{
    typename cont_type::insert_commit_data d;
    auto const result(cont_.insert_check(extract(value), std::cref(config_.keyCompare()), d));
    if (result.second)
    {
        Element* const p(newElement(std::move(value)));
        auto const iter(cont_.insert_commit(*p, d));
        chronological.list_.push_back(*p);
        return std::make_pair(iterator(iter), true);
    }
    return std::make_pair(iterator(result.first), false);
}

// multiset
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti, bool MaybeMap>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::insert(value_type&& value)
    -> iterator
    requires(MaybeMulti && !MaybeMap)
{
    auto const before(cont_.upper_bound(extract(value), std::cref(config_.keyCompare())));
    Element* const p(newElement(std::move(value)));
    chronological.list_.push_back(*p);
    auto const iter(cont_.insert_before(before, *p));
    return iterator(iter);
}

//---

// map, set
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::insert(
    const_iterator hint,
    value_type const& value) -> iterator
    requires(!MaybeMulti)
{
    typename cont_type::insert_commit_data d;
    auto const result(
        cont_.insert_check(hint.iterator(), extract(value), std::cref(config_.keyCompare()), d));
    if (result.second)
    {
        Element* const p(newElement(value));
        auto const iter(cont_.insert_commit(*p, d));
        chronological.list_.push_back(*p);
        return iterator(iter);
    }
    return iterator(result.first);
}

// map, set
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::insert(
    const_iterator hint,
    value_type&& value) -> iterator
    requires(!MaybeMulti)
{
    typename cont_type::insert_commit_data d;
    auto const result(
        cont_.insert_check(hint.iterator(), extract(value), std::cref(config_.keyCompare()), d));
    if (result.second)
    {
        Element* const p(newElement(std::move(value)));
        auto const iter(cont_.insert_commit(*p, d));
        chronological.list_.push_back(*p);
        return iterator(iter);
    }
    return iterator(result.first);
}

// map, set
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti, class... Args>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::emplace(Args&&... args)
    -> std::pair<iterator, bool>
    requires(!MaybeMulti)
{
    // VFALCO NOTE Its unfortunate that we need to
    //             construct element here
    Element* const p(newElement(std::forward<Args>(args)...));
    typename cont_type::insert_commit_data d;
    auto const result(cont_.insert_check(extract(p->value), std::cref(config_.keyCompare()), d));
    if (result.second)
    {
        auto const iter(cont_.insert_commit(*p, d));
        chronological.list_.push_back(*p);
        return std::make_pair(iterator(iter), true);
    }
    deleteElement(p);
    return std::make_pair(iterator(result.first), false);
}

// multiset, multimap
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti, class... Args>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::emplace(Args&&... args)
    -> iterator
    requires MaybeMulti
{
    Element* const p(newElement(std::forward<Args>(args)...));
    auto const before(cont_.upper_bound(extract(p->value), std::cref(config_.keyCompare())));
    chronological.list_.push_back(*p);
    auto const iter(cont_.insert_before(before, *p));
    return iterator(iter);
}

// map, set
template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybeMulti, class... Args>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::emplaceHint(
    const_iterator hint,
    Args&&... args) -> std::pair<iterator, bool>
    requires(!MaybeMulti)
{
    // VFALCO NOTE Its unfortunate that we need to
    //             construct element here
    Element* const p(newElement(std::forward<Args>(args)...));
    typename cont_type::insert_commit_data d;
    auto const result(
        cont_.insert_check(hint.iterator(), extract(p->value), std::cref(config_.keyCompare()), d));
    if (result.second)
    {
        auto const iter(cont_.insert_commit(*p, d));
        chronological.list_.push_back(*p);
        return std::make_pair(iterator(iter), true);
    }
    deleteElement(p);
    return std::make_pair(iterator(result.first), false);
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool IsConst, class Iterator>
beast::detail::AgedContainerIterator<false, Iterator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::erase(
    beast::detail::AgedContainerIterator<IsConst, Iterator> pos)
    requires(!IsBoostReverseIterator<Iterator>::value)
{
    unlinkAndDeleteElement(&*((pos++).iterator()));
    return beast::detail::AgedContainerIterator<false, Iterator>(pos.iterator());
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool IsConst, class Iterator>
beast::detail::AgedContainerIterator<false, Iterator>
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::erase(
    beast::detail::AgedContainerIterator<IsConst, Iterator> first,
    beast::detail::AgedContainerIterator<IsConst, Iterator> last)
    requires(!IsBoostReverseIterator<Iterator>::value)
{
    for (; first != last;)
        unlinkAndDeleteElement(&*((first++).iterator()));

    return beast::detail::AgedContainerIterator<false, Iterator>(first.iterator());
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <class K>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::erase(K const& k)
    -> size_type
{
    auto iter(cont_.find(k, std::cref(config_.keyCompare())));
    if (iter == cont_.end())
        return 0;
    size_type n(0);
    for (;;)
    {
        auto p(&*iter++);
        bool const done(config_(*p, extract(iter->value)));
        unlinkAndDeleteElement(p);
        ++n;
        if (done)
            break;
    }
    return n;
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
void
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::swap(
    AgedOrderedContainer& other) noexcept
{
    swapData(other);
    std::swap(chronological, other.chronological);
    std::swap(cont_, other.cont_);
}

//------------------------------------------------------------------------------

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <class K>
auto
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::touch(K const& k)
    -> size_type
{
    auto const now(clock().now());
    size_type n(0);
    auto const range(equalRange(k));
    for (auto iter : range)
    {
        touch(iter, now);
        ++n;
    }
    return n;
}

//------------------------------------------------------------------------------

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <
    bool OtherIsMulti,
    bool OtherIsMap,
    class OtherT,
    class OtherDuration,
    class OtherAllocator>
bool
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::operator==(
    AgedOrderedContainer<
        OtherIsMulti,
        OtherIsMap,
        Key,
        OtherT,
        OtherDuration,
        Compare,
        OtherAllocator> const& other) const
{
    using Other = AgedOrderedContainer<
        OtherIsMulti,
        OtherIsMap,
        Key,
        OtherT,
        OtherDuration,
        Compare,
        OtherAllocator>;
    if (size() != other.size())
        return false;
    std::equal_to<void> eq;
    return std::equal(
        cbegin(),
        cend(),
        other.cbegin(),
        other.cend(),
        [&eq, &other](value_type const& lhs, Other::value_type const& rhs) {
            return eq(extract(lhs), other.extract(rhs));
        });
}

//------------------------------------------------------------------------------

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool IsConst, class Iterator>
void
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::touch(
    beast::detail::AgedContainerIterator<IsConst, Iterator> pos,
    clock_type::time_point const& now)
    requires(!IsBoostReverseIterator<Iterator>::value)
{
    auto& e(*pos.iterator());
    e.when = now;
    chronological.list_.erase(chronological.list_.iterator_to(e));
    chronological.list_.push_back(e);
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybePropagate>
void
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::swapData(
    AgedOrderedContainer& other) noexcept
    requires MaybePropagate
{
    std::swap(config_.keyCompare(), other.config_.keyCompare());
    std::swap(config_.alloc(), other.config_.alloc());
    std::swap(config_.clock, other.config_.clock);
}

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
template <bool MaybePropagate>
void
AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>::swapData(
    AgedOrderedContainer& other) noexcept
    requires(!MaybePropagate)
{
    std::swap(config_.keyCompare(), other.config_.keyCompare());
    std::swap(config_.clock, other.config_.clock);
}

}  // namespace detail

//------------------------------------------------------------------------------

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
struct IsAgedContainer<
    beast::detail::AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>>
    : std::true_type
{
    explicit IsAgedContainer() = default;
};

// Free functions

template <bool IsMulti, bool IsMap, class Key, class T, class Clock, class Compare, class Allocator>
void
swap(
    beast::detail::AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>& lhs,
    beast::detail::AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>&
        rhs) noexcept
{
    lhs.swap(rhs);
}

/**
 * Expire aged container items past the specified age.
 */
template <
    bool IsMulti,
    bool IsMap,
    class Key,
    class T,
    class Clock,
    class Compare,
    class Allocator,
    class Rep,
    class Period>
std::size_t
expire(
    detail::AgedOrderedContainer<IsMulti, IsMap, Key, T, Clock, Compare, Allocator>& c,
    std::chrono::duration<Rep, Period> const& age)
{
    std::size_t n(0);
    auto const expired(c.clock().now() - age);
    for (auto iter(c.chronological.cbegin());
         iter != c.chronological.cend() && iter.when() <= expired;)
    {
        iter = c.erase(iter);
        ++n;
    }
    return n;
}

}  // namespace beast