PeerReservationTable.cpp

#include <xrpl/core/PeerReservationTable.h>
 
#include <xrpl/json/json_value.h>
#include <xrpl/protocol/PublicKey.h>
#include <xrpl/protocol/jss.h>
#include <xrpl/protocol/tokens.h>
#include <xrpl/server/Wallet.h>
 
#include <algorithm>
#include <iterator>
#include <mutex>
#include <optional>
#include <string>
#include <vector>
 
namespace xrpl {
 
auto
PeerReservation::toJson() const -> json::Value
{
    json::Value result{json::ValueType::Object};
    result[jss::node] = toBase58(TokenType::NodePublic, nodeId);
    if (!description.empty())
    {
        result[jss::description] = description;
    }
    return result;
}
 
auto
PeerReservationTable::list() const -> std::vector<PeerReservation>
{
    std::vector<PeerReservation> list;
    {
        std::scoped_lock const lock(mutex_);
        list.reserve(table_.size());
        std::ranges::copy(table_, std::back_inserter(list));
    }
    std::sort(list.begin(), list.end());  // NOLINT(modernize-use-ranges)
    return list;
}
 
// See `include/xrpl/rdb/DBInit.h` for the `CREATE TABLE` statement.
// It is unfortunate that we do not get to define a function for it.
 
// We choose a `bool` return type to fit in with the error handling scheme
// of other functions called from `ApplicationImp::setup`, but we always
// return "no error" (`true`) because we can always return an empty table.
bool
PeerReservationTable::load(DatabaseCon& connection)
{
    std::scoped_lock const lock(mutex_);
 
    connection_ = &connection;
    auto db = connection.checkoutDb();
    auto table = getPeerReservationTable(*db, journal_);
    table_.insert(table.begin(), table.end());
 
    return true;
}
 
std::optional<PeerReservation>
PeerReservationTable::insertOrAssign(PeerReservation const& reservation)
{
    std::optional<PeerReservation> previous;
 
    std::scoped_lock const lock(mutex_);
 
    auto hint = table_.find(reservation);
    if (hint != table_.end())
    {
        // The node already has a reservation. Remove it.
        // `std::unordered_set` does not have an `insertOrAssign` method,
        // and sadly makes it impossible for us to implement one efficiently:
        // https://stackoverflow.com/q/49651835/618906
        // Regardless, we don't expect this function to be called often, or
        // for the table to be very large, so this less-than-ideal
        // remove-then-insert is acceptable in order to present a better API.
        previous = *hint;
        // We should pick an adjacent location for the insertion hint.
        // Decrementing may be illegal if the found reservation is at the
        // beginning. Incrementing is always legal; at worst we'll point to
        // the end.
        auto const deleteme = hint;
        ++hint;
        table_.erase(deleteme);
    }
    table_.insert(hint, reservation);
 
    auto db = connection_->checkoutDb();
    insertPeerReservation(*db, reservation.nodeId, reservation.description);
 
    return previous;
}
 
std::optional<PeerReservation>
PeerReservationTable::erase(PublicKey const& nodeId)
{
    std::optional<PeerReservation> previous;
 
    std::scoped_lock const lock(mutex_);
 
    auto const it = table_.find({.nodeId = nodeId});
    if (it != table_.end())
    {
        previous = *it;
        table_.erase(it);
        auto db = connection_->checkoutDb();
        deletePeerReservation(*db, nodeId);
    }
 
    return previous;
}
 
}  // namespace xrpl