PeerReservationTable.h

#pragma once
 
#include <xrpl/beast/hash/hash_append.h>
#include <xrpl/beast/hash/uhash.h>
#include <xrpl/beast/utility/Journal.h>
#include <xrpl/protocol/PublicKey.h>
 
#include <mutex>
#include <optional>
#include <string>
#include <unordered_set>
#include <vector>
 
namespace xrpl {
 
class DatabaseCon;
 
// Value type for reservations.
struct PeerReservation final
{
public:
    PublicKey nodeId;
    std::string description = {};  // NOLINT(readability-redundant-member-init)
 
    [[nodiscard]] auto
    toJson() const -> json::Value;
 
    template <typename Hasher>
    friend void
    hash_append(
        Hasher& h,
        PeerReservation const& x) noexcept  // NOLINT(readability-identifier-naming)
    {
        using beast::hash_append;
        hash_append(h, x.nodeId);
    }
 
    friend bool
    operator<(PeerReservation const& a, PeerReservation const& b)
    {
        return a.nodeId < b.nodeId;
    }
};
 
// TODO: When C++20 arrives, take advantage of "equivalence" instead of
// "equality". Add an overload for `(PublicKey, PeerReservation)`, and just
// pass a `PublicKey` directly to `unordered_set.find`.
struct KeyEqual final
{
    bool
    operator()(PeerReservation const& lhs, PeerReservation const& rhs) const
    {
        return lhs.nodeId == rhs.nodeId;
    }
};
 
class PeerReservationTable final
{
public:
    explicit PeerReservationTable(
        beast::Journal journal = beast::Journal(beast::Journal::getNullSink()))
        : journal_(journal)
    {
    }
 
    std::vector<PeerReservation>
    list() const;
 
    bool
    contains(PublicKey const& nodeId)
    {
        std::scoped_lock const lock(this->mutex_);
        return table_.contains({.nodeId = nodeId, .description = {}});
    }
 
    // Because `ApplicationImp` has two-phase initialization, so must we.
    // Our dependencies are not prepared until the second phase.
    bool
    load(DatabaseCon& connection);

    std::optional<PeerReservation>
    insertOrAssign(PeerReservation const& reservation);

    std::optional<PeerReservation>
    erase(PublicKey const& nodeId);
 
private:
    beast::Journal mutable journal_;
    std::mutex mutable mutex_;
    DatabaseCon* connection_{};
    std::unordered_set<PeerReservation, beast::Uhash<>, KeyEqual> table_;
};
 
}  // namespace xrpl