libxrpl/ledger/Ledger.cpp

#include <xrpl/ledger/Ledger.h>
 
#include <xrpl/basics/Log.h>
#include <xrpl/basics/Slice.h>
#include <xrpl/basics/UnorderedContainers.h>
#include <xrpl/basics/base_uint.h>
#include <xrpl/basics/chrono.h>
#include <xrpl/basics/contract.h>
#include <xrpl/beast/utility/Journal.h>
#include <xrpl/beast/utility/Zero.h>
#include <xrpl/beast/utility/instrumentation.h>
#include <xrpl/ledger/LedgerTiming.h>
#include <xrpl/ledger/ReadView.h>
#include <xrpl/ledger/entries/FeeSettingsEntry.h>
#include <xrpl/ledger/entries/NegativeUNLEntry.h>
#include <xrpl/nodestore/NodeObject.h>
#include <xrpl/protocol/Feature.h>
#include <xrpl/protocol/Fees.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/KeyType.h>
#include <xrpl/protocol/Keylet.h>
#include <xrpl/protocol/LedgerHeader.h>
#include <xrpl/protocol/Protocol.h>
#include <xrpl/protocol/PublicKey.h>
#include <xrpl/protocol/Rules.h>
#include <xrpl/protocol/SField.h>
#include <xrpl/protocol/STArray.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <xrpl/protocol/STObject.h>
#include <xrpl/protocol/STTx.h>
#include <xrpl/protocol/SecretKey.h>
#include <xrpl/protocol/Seed.h>
#include <xrpl/protocol/Serializer.h>
#include <xrpl/protocol/SystemParameters.h>
#include <xrpl/shamap/Family.h>
#include <xrpl/shamap/SHAMap.h>
#include <xrpl/shamap/SHAMapItem.h>
#include <xrpl/shamap/SHAMapMissingNode.h>
#include <xrpl/shamap/SHAMapTreeNode.h>
 
#include <algorithm>
#include <cstdint>
#include <exception>
#include <memory>
#include <optional>
#include <utility>
#include <vector>
 
namespace xrpl {
 
CreateGenesisT const kCreateGenesis{};
 
//------------------------------------------------------------------------------
 
class Ledger::SlesIterImpl : public SlesType::IterBase
{
private:
    SHAMap::ConstIterator iter_;
 
public:
    SlesIterImpl() = delete;
    SlesIterImpl&
    operator=(SlesIterImpl const&) = delete;
 
    SlesIterImpl(SlesIterImpl const&) = default;
 
    SlesIterImpl(SHAMap::ConstIterator iter) : iter_(iter)
    {
    }
 
    [[nodiscard]] std::unique_ptr<BaseType>
    copy() const override
    {
        return std::make_unique<SlesIterImpl>(*this);
    }
 
    [[nodiscard]] bool
    equal(BaseType const& impl) const override
    {
        if (auto const p = dynamic_cast<SlesIterImpl const*>(&impl))
            return iter_ == p->iter_;
        return false;
    }
 
    void
    increment() override
    {
        ++iter_;
    }
 
    [[nodiscard]] SlesType::value_type
    dereference() const override
    {
        SerialIter sit(iter_->slice());
        return std::make_shared<SLE const>(sit, iter_->key());
    }
};
 
//------------------------------------------------------------------------------
 
class Ledger::TxsIterImpl : public TxsType::IterBase
{
private:
    bool metadata_;
    SHAMap::ConstIterator iter_;
 
public:
    TxsIterImpl() = delete;
    TxsIterImpl&
    operator=(TxsIterImpl const&) = delete;
 
    TxsIterImpl(TxsIterImpl const&) = default;
 
    TxsIterImpl(bool metadata, SHAMap::ConstIterator iter) : metadata_(metadata), iter_(iter)
    {
    }
 
    [[nodiscard]] std::unique_ptr<BaseType>
    copy() const override
    {
        return std::make_unique<TxsIterImpl>(*this);
    }
 
    [[nodiscard]] bool
    equal(BaseType const& impl) const override
    {
        if (auto const p = dynamic_cast<TxsIterImpl const*>(&impl))
            return iter_ == p->iter_;
        return false;
    }
 
    void
    increment() override
    {
        ++iter_;
    }
 
    [[nodiscard]] TxsType::value_type
    dereference() const override
    {
        auto const& item = *iter_;
        if (metadata_)
            return Ledger::deserializeTxPlusMeta(item);
        return {Ledger::deserializeTx(item), nullptr};
    }
};
 
//------------------------------------------------------------------------------
 
Ledger::Ledger(
    CreateGenesisT,
    Rules rules,
    Fees const& fees,
    std::vector<UInt256> const& amendments,
    Family& family)
    : immutable_(false)
    , txMap_(SHAMapType::TRANSACTION, family)
    , stateMap_(SHAMapType::STATE, family)
    , fees_(fees)
    , rules_(std::move(rules))
    , j_(beast::Journal(beast::Journal::getNullSink()))
{
    header_.seq = 1;
    header_.drops = kInitialXrp;
    header_.closeTimeResolution = kLedgerGenesisTimeResolution;
 
    static auto const kID =
        calcAccountID(generateKeyPair(KeyType::Secp256k1, generateSeed("masterpassphrase")).first);
    {
        auto const sle = std::make_shared<SLE>(keylet::account(kID));
        sle->setFieldU32(sfSequence, 1);
        sle->setAccountID(sfAccount, kID);
        sle->setFieldAmount(sfBalance, header_.drops);
        rawInsert(sle);
    }
 
    if (!amendments.empty())
    {
        auto const sle = std::make_shared<SLE>(keylet::amendments());
        sle->setFieldV256(sfAmendments, STVector256{amendments});
        rawInsert(sle);
    }
 
    {
        auto sle = std::make_shared<SLE>(keylet::feeSettings());
        // Whether featureXRPFees is supported will depend on startup options.
        if (std::ranges::find(amendments, featureXRPFees) != amendments.end())
        {
            sle->at(sfBaseFeeDrops) = fees.base;
            sle->at(sfReserveBaseDrops) = fees.reserve;
            sle->at(sfReserveIncrementDrops) = fees.increment;
        }
        else
        {
            if (auto const f = fees.base.dropsAs<std::uint64_t>())
                sle->at(sfBaseFee) = *f;
            if (auto const f = fees.reserve.dropsAs<std::uint32_t>())
                sle->at(sfReserveBase) = *f;
            if (auto const f = fees.increment.dropsAs<std::uint32_t>())
                sle->at(sfReserveIncrement) = *f;
            sle->at(sfReferenceFeeUnits) = kFeeUnitsDeprecated;
        }
        rawInsert(sle);
    }
 
    stateMap_.flushDirty(NodeObjectType::AccountNode);
    setImmutable();
}
 
Ledger::Ledger(
    LedgerHeader const& info,
    bool& loaded,
    bool acquire,
    Rules rules,
    Fees const& fees,
    Family& family,
    beast::Journal j)
    : immutable_(true)
    , txMap_(SHAMapType::TRANSACTION, info.txHash, family)
    , stateMap_(SHAMapType::STATE, info.accountHash, family)
    , fees_(fees)
    , rules_(std::move(rules))
    , header_(info)
    , j_(j)
{
    loaded = true;
 
    if (header_.txHash.isNonZero() && !txMap_.fetchRoot(SHAMapHash{header_.txHash}, nullptr))
    {
        loaded = false;
        JLOG(j.warn()) << "Don't have transaction root for ledger" << header_.seq;
    }
 
    if (header_.accountHash.isNonZero() &&
        !stateMap_.fetchRoot(SHAMapHash{header_.accountHash}, nullptr))
    {
        loaded = false;
        JLOG(j.warn()) << "Don't have state data root for ledger" << header_.seq;
    }
 
    txMap_.setImmutable();
    stateMap_.setImmutable();
 
    if (!setup())
        loaded = false;
 
    if (!loaded)
    {
        header_.hash = calculateLedgerHash(header_);
        if (acquire)
            family.missingNodeAcquireByHash(header_.hash, header_.seq);
    }
}
 
// Create a new ledger that follows this one
Ledger::Ledger(Ledger const& prevLedger, NetClock::time_point closeTime)
    : immutable_(false)
    , txMap_(SHAMapType::TRANSACTION, prevLedger.txMap_.family())
    , stateMap_(prevLedger.stateMap_, true)
    , fees_(prevLedger.fees_)
    , rules_(prevLedger.rules_)
    , j_(beast::Journal(beast::Journal::getNullSink()))
{
    header_.seq = prevLedger.header_.seq + 1;
    header_.parentCloseTime = prevLedger.header_.closeTime;
    header_.hash = prevLedger.header().hash + UInt256(1);
    header_.drops = prevLedger.header().drops;
    header_.closeTimeResolution = prevLedger.header_.closeTimeResolution;
    header_.parentHash = prevLedger.header().hash;
    header_.closeTimeResolution = getNextLedgerTimeResolution(
        prevLedger.header_.closeTimeResolution, getCloseAgree(prevLedger.header()), header_.seq);
 
    if (prevLedger.header_.closeTime == NetClock::time_point{})
    {
        header_.closeTime = roundCloseTime(closeTime, header_.closeTimeResolution);
    }
    else
    {
        header_.closeTime = prevLedger.header_.closeTime + header_.closeTimeResolution;
    }
}
 
Ledger::Ledger(LedgerHeader const& info, Rules rules, Family& family)
    : immutable_(true)
    , txMap_(SHAMapType::TRANSACTION, info.txHash, family)
    , stateMap_(SHAMapType::STATE, info.accountHash, family)
    , rules_(std::move(rules))
    , header_(info)
    , j_(beast::Journal(beast::Journal::getNullSink()))
{
    header_.hash = calculateLedgerHash(header_);
}
 
Ledger::Ledger(
    std::uint32_t ledgerSeq,
    NetClock::time_point closeTime,
    Rules rules,
    Fees const& fees,
    Family& family)
    : immutable_(false)
    , txMap_(SHAMapType::TRANSACTION, family)
    , stateMap_(SHAMapType::STATE, family)
    , fees_(fees)
    , rules_(std::move(rules))
    , j_(beast::Journal(beast::Journal::getNullSink()))
{
    header_.seq = ledgerSeq;
    header_.closeTime = closeTime;
    header_.closeTimeResolution = kLedgerDefaultTimeResolution;
    setup();
}
 
void
Ledger::setImmutable(bool rehash)
{
    // Force update, since this is the only
    // place the hash transitions to valid
    if (!immutable_ && rehash)
    {
        header_.txHash = txMap_.getHash().asUInt256();
        header_.accountHash = stateMap_.getHash().asUInt256();
    }
 
    if (rehash)
        header_.hash = calculateLedgerHash(header_);
 
    immutable_ = true;
    txMap_.setImmutable();
    stateMap_.setImmutable();
    setup();
}
 
void
Ledger::setAccepted(
    NetClock::time_point closeTime,
    NetClock::duration closeResolution,
    bool correctCloseTime)
{
    // Used when we witnessed the consensus.
    XRPL_ASSERT(!open(), "xrpl::Ledger::setAccepted : valid ledger state");
 
    header_.closeTime = closeTime;
    header_.closeTimeResolution = closeResolution;
    header_.closeFlags = correctCloseTime ? 0 : kSLcfNoConsensusTime;
    setImmutable();
}
 
bool
Ledger::addSLE(SLE const& sle)
{
    auto const s = sle.getSerializer();
    return stateMap_.addItem(SHAMapNodeType::TnAccountState, makeShamapitem(sle.key(), s.slice()));
}
 
//------------------------------------------------------------------------------
 
std::shared_ptr<STTx const>
Ledger::deserializeTx(SHAMapItem const& item)
{
    SerialIter sit(item.slice());
    return std::make_shared<STTx const>(sit);
}
 
std::pair<std::shared_ptr<STTx const>, std::shared_ptr<STObject const>>
Ledger::deserializeTxPlusMeta(SHAMapItem const& item)
{
    std::pair<std::shared_ptr<STTx const>, std::shared_ptr<STObject const>> result;
    SerialIter sit(item.slice());
    {
        SerialIter s(sit.getSlice(sit.getVLDataLength()));
        result.first = std::make_shared<STTx const>(s);
    }
    {
        SerialIter s(sit.getSlice(sit.getVLDataLength()));
        result.second = std::make_shared<STObject const>(s, sfMetadata);
    }
    return result;
}
 
//------------------------------------------------------------------------------
 
bool
Ledger::exists(Keylet const& k) const
{
    // VFALCO NOTE Perhaps check the type for debug builds?
    return stateMap_.hasItem(k.key);
}
 
bool
Ledger::exists(UInt256 const& key) const
{
    return stateMap_.hasItem(key);
}
 
std::optional<UInt256>
Ledger::succ(UInt256 const& key, std::optional<UInt256> const& last) const
{
    auto item = stateMap_.upperBound(key);
    if (item == stateMap_.end())
        return std::nullopt;
    if (last && item->key() >= last)
        return std::nullopt;
    return item->key();
}
 
SLE::const_pointer
Ledger::read(Keylet const& k) const
{
    if (k.key == beast::kZero)
    {
        // LCOV_EXCL_START
        UNREACHABLE("xrpl::Ledger::read : zero key");
        return nullptr;
        // LCOV_EXCL_STOP
    }
    auto const& item = stateMap_.peekItem(k.key);
    if (!item)
        return nullptr;
    auto sle = std::make_shared<SLE>(SerialIter{item->slice()}, item->key());
    if (!k.check(*sle))
        return nullptr;
    return sle;
}
 
//------------------------------------------------------------------------------
 
auto
Ledger::slesBegin() const -> std::unique_ptr<SlesType::IterBase>
{
    return std::make_unique<SlesIterImpl>(stateMap_.begin());
}
 
auto
Ledger::slesEnd() const -> std::unique_ptr<SlesType::IterBase>
{
    return std::make_unique<SlesIterImpl>(stateMap_.end());
}
 
auto
Ledger::slesUpperBound(UInt256 const& key) const -> std::unique_ptr<SlesType::IterBase>
{
    return std::make_unique<SlesIterImpl>(stateMap_.upperBound(key));
}
 
auto
Ledger::txsBegin() const -> std::unique_ptr<TxsType::IterBase>
{
    return std::make_unique<TxsIterImpl>(!open(), txMap_.begin());
}
 
auto
Ledger::txsEnd() const -> std::unique_ptr<TxsType::IterBase>
{
    return std::make_unique<TxsIterImpl>(!open(), txMap_.end());
}
 
bool
Ledger::txExists(UInt256 const& key) const
{
    return txMap_.hasItem(key);
}
 
auto
Ledger::txRead(key_type const& key) const -> TxType
{
    auto const& item = txMap_.peekItem(key);
    if (!item)
        return {};
    if (!open())
    {
        auto result = deserializeTxPlusMeta(*item);
        return {std::move(result.first), std::move(result.second)};
    }
    return {deserializeTx(*item), nullptr};
}
 
auto
Ledger::digest(key_type const& key) const -> std::optional<DigestType>
{
    SHAMapHash digest;
    // VFALCO Unfortunately this loads the item
    //        from the NodeStore needlessly.
    if (!stateMap_.peekItem(key, digest))
        return std::nullopt;
    return digest.asUInt256();
}
 
//------------------------------------------------------------------------------
 
void
Ledger::rawErase(SLE::Ref sle)
{
    if (!stateMap_.delItem(sle->key()))
        logicError("Ledger::rawErase: key not found");
}
 
void
Ledger::rawErase(UInt256 const& key)
{
    if (!stateMap_.delItem(key))
        logicError("Ledger::rawErase: key not found");
}
 
void
Ledger::rawInsert(SLE::Ref sle)
{
    Serializer ss;
    sle->add(ss);
    if (!stateMap_.addGiveItem(
            SHAMapNodeType::TnAccountState, makeShamapitem(sle->key(), ss.slice())))
    {
        logicError("Ledger::rawInsert: key already exists");
    }
}
 
void
Ledger::rawReplace(SLE::Ref sle)
{
    Serializer ss;
    sle->add(ss);
    if (!stateMap_.updateGiveItem(
            SHAMapNodeType::TnAccountState, makeShamapitem(sle->key(), ss.slice())))
    {
        logicError("Ledger::rawReplace: key not found");
    }
}
 
void
Ledger::rawTxInsert(
    UInt256 const& key,
    std::shared_ptr<Serializer const> const& txn,
    std::shared_ptr<Serializer const> const& metaData)
{
    XRPL_ASSERT(metaData, "xrpl::Ledger::rawTxInsert : non-null metadata input");
 
    // low-level - just add to table
    Serializer s(txn->getDataLength() + metaData->getDataLength() + 16);
    s.addVL(txn->peekData());
    s.addVL(metaData->peekData());
    if (!txMap_.addGiveItem(SHAMapNodeType::TnTransactionMd, makeShamapitem(key, s.slice())))
        logicError("duplicate_tx: " + to_string(key));
}
 
bool
Ledger::setup()
{
    bool ret = true;
 
    try
    {
        rules_ = makeRulesGivenLedger(*this, rules_);
    }
    catch (SHAMapMissingNode const&)
    {
        ret = false;
    }
    catch (std::exception const& ex)
    {
        JLOG(j_.error()) << "Exception in " << __func__ << ": " << ex.what();
        rethrow();
    }
 
    try
    {
        if (auto const sle = FeeSettingsEntryR(*this))
        {
            bool oldFees = false;
            bool newFees = false;
            {
                auto const baseFee = sle->at(~sfBaseFee);
                auto const reserveBase = sle->at(~sfReserveBase);
                auto const reserveIncrement = sle->at(~sfReserveIncrement);
                if (baseFee)
                    fees_.base = *baseFee;
                if (reserveBase)
                    fees_.reserve = *reserveBase;
                if (reserveIncrement)
                    fees_.increment = *reserveIncrement;
                oldFees = baseFee || reserveBase || reserveIncrement;
            }
            {
                auto const baseFeeXRP = sle->at(~sfBaseFeeDrops);
                auto const reserveBaseXRP = sle->at(~sfReserveBaseDrops);
                auto const reserveIncrementXRP = sle->at(~sfReserveIncrementDrops);
                auto assign = [&ret](XRPAmount& dest, std::optional<STAmount> const& src) {
                    if (src)
                    {
                        if (src->native())
                        {
                            dest = src->xrp();
                        }
                        else
                        {
                            ret = false;
                        }
                    }
                };
                assign(fees_.base, baseFeeXRP);
                assign(fees_.reserve, reserveBaseXRP);
                assign(fees_.increment, reserveIncrementXRP);
                newFees = baseFeeXRP || reserveBaseXRP || reserveIncrementXRP;
            }
            if (oldFees && newFees)
            {
                // Should be all of one or the other, but not both
                ret = false;
            }
            if (!rules_.enabled(featureXRPFees) && newFees)
            {
                // Can't populate the new fees before the amendment is enabled
                ret = false;
            }
        }
    }
    catch (SHAMapMissingNode const&)
    {
        ret = false;
    }
    catch (std::exception const& ex)
    {
        JLOG(j_.error()) << "Exception in " << __func__ << ": " << ex.what();
        rethrow();
    }
 
    return ret;
}
 
SLE::pointer
Ledger::peek(Keylet const& k) const
{
    auto const& value = stateMap_.peekItem(k.key);
    if (!value)
        return nullptr;
    auto sle = std::make_shared<SLE>(SerialIter{value->slice()}, value->key());
    if (!k.check(*sle))
        return nullptr;
    return sle;
}
 
HashSet<PublicKey>
Ledger::negativeUNL() const
{
    HashSet<PublicKey> negUnl;
    if (auto const sle = NegativeUNLEntryR(*this); sle && sle->isFieldPresent(sfDisabledValidators))
    {
        auto const& nUnlData = sle->getFieldArray(sfDisabledValidators);
        for (auto const& n : nUnlData)
        {
            if (n.isFieldPresent(sfPublicKey))
            {
                auto d = n.getFieldVL(sfPublicKey);
                auto s = makeSlice(d);
                if (!publicKeyType(s))
                {
                    continue;
                }
                negUnl.emplace(s);
            }
        }
    }
 
    return negUnl;
}
 
std::optional<PublicKey>
Ledger::validatorToDisable() const
{
    if (auto const sle = NegativeUNLEntryR(*this); sle && sle->isFieldPresent(sfValidatorToDisable))
    {
        auto d = sle->getFieldVL(sfValidatorToDisable);
        auto s = makeSlice(d);
        if (publicKeyType(s))
            return PublicKey(s);
    }
 
    return std::nullopt;
}
 
std::optional<PublicKey>
Ledger::validatorToReEnable() const
{
    if (auto const sle = NegativeUNLEntryR(*this);
        sle && sle->isFieldPresent(sfValidatorToReEnable))
    {
        auto d = sle->getFieldVL(sfValidatorToReEnable);
        auto s = makeSlice(d);
        if (publicKeyType(s))
            return PublicKey(s);
    }
 
    return std::nullopt;
}
 
void
Ledger::updateNegativeUNL()
{
    auto sle = peek(keylet::negativeUNL());
    if (!sle)
        return;
 
    bool const hasToDisable = sle->isFieldPresent(sfValidatorToDisable);
    bool const hasToReEnable = sle->isFieldPresent(sfValidatorToReEnable);
 
    if (!hasToDisable && !hasToReEnable)
        return;
 
    STArray newNUnl;
    if (sle->isFieldPresent(sfDisabledValidators))
    {
        auto const& oldNUnl = sle->getFieldArray(sfDisabledValidators);
        for (auto const& v : oldNUnl)
        {
            if (hasToReEnable && v.isFieldPresent(sfPublicKey) &&
                v.getFieldVL(sfPublicKey) == sle->getFieldVL(sfValidatorToReEnable))
                continue;
            newNUnl.pushBack(v);
        }
    }
 
    if (hasToDisable)
    {
        newNUnl.pushBack(STObject::makeInnerObject(sfDisabledValidator));
        newNUnl.back().setFieldVL(sfPublicKey, sle->getFieldVL(sfValidatorToDisable));
        newNUnl.back().setFieldU32(sfFirstLedgerSequence, seq());
    }
 
    if (!newNUnl.empty())
    {
        sle->setFieldArray(sfDisabledValidators, newNUnl);
        if (hasToReEnable)
            sle->makeFieldAbsent(sfValidatorToReEnable);
        if (hasToDisable)
            sle->makeFieldAbsent(sfValidatorToDisable);
        rawReplace(sle);
    }
    else
    {
        rawErase(sle);
    }
}
 
//------------------------------------------------------------------------------
bool
Ledger::walkLedger(beast::Journal j, bool parallel) const
{
    std::vector<SHAMapMissingNode> missingNodes1;
    std::vector<SHAMapMissingNode> missingNodes2;
 
    if (stateMap_.getHash().isZero() && !header_.accountHash.isZero() &&
        !stateMap_.fetchRoot(SHAMapHash{header_.accountHash}, nullptr))
    {
        missingNodes1.emplace_back(SHAMapType::STATE, SHAMapHash{header_.accountHash});
    }
    else
    {
        if (parallel)
        {
            return stateMap_.walkMapParallel(missingNodes1, 32);
        }
 
        stateMap_.walkMap(missingNodes1, 32);
    }
 
    if (!missingNodes1.empty())
    {
        if (auto stream = j.info())
        {
            stream << missingNodes1.size() << " missing account node(s)";
            stream << "First: " << missingNodes1[0].what();
        }
    }
 
    if (txMap_.getHash().isZero() && header_.txHash.isNonZero() &&
        !txMap_.fetchRoot(SHAMapHash{header_.txHash}, nullptr))
    {
        missingNodes2.emplace_back(SHAMapType::TRANSACTION, SHAMapHash{header_.txHash});
    }
    else
    {
        txMap_.walkMap(missingNodes2, 32);
    }
 
    if (!missingNodes2.empty())
    {
        if (auto stream = j.info())
        {
            stream << missingNodes2.size() << " missing transaction node(s)";
            stream << "First: " << missingNodes2[0].what();
        }
    }
    return missingNodes1.empty() && missingNodes2.empty();
}
 
bool
Ledger::isSensible() const
{
    if (header_.hash.isZero())
        return false;
    if (header_.accountHash.isZero())
        return false;
    if (header_.accountHash != stateMap_.getHash().asUInt256())
        return false;
    if (header_.txHash != txMap_.getHash().asUInt256())
        return false;
    return true;
}
 
// update the skip list with the information from our previous ledger
// VFALCO TODO Document this skip list concept
void
Ledger::updateSkipList()
{
    if (header_.seq == 0)  // genesis ledger has no previous ledger
        return;
 
    std::uint32_t const prevIndex = header_.seq - 1;
 
    // update record of every 256th ledger
    if ((prevIndex & 0xff) == 0)
    {
        auto const k = keylet::skip(prevIndex);
        auto sle = peek(k);
        std::vector<UInt256> hashes;
 
        bool created = false;
        if (!sle)
        {
            sle = std::make_shared<SLE>(k);
            created = true;
        }
        else
        {
            hashes = static_cast<decltype(hashes)>(sle->getFieldV256(sfHashes));
            created = false;
        }
 
        XRPL_ASSERT(
            hashes.size() <= 256, "xrpl::Ledger::updateSkipList : first maximum hashes size");
        hashes.push_back(header_.parentHash);
        sle->setFieldV256(sfHashes, STVector256(hashes));
        sle->setFieldU32(sfLastLedgerSequence, prevIndex);
        if (created)
        {
            rawInsert(sle);
        }
        else
        {
            rawReplace(sle);
        }
    }
 
    // update record of past 256 ledger
    auto const k = keylet::skip();
    auto sle = peek(k);
    std::vector<UInt256> hashes;
    bool created = false;
    if (!sle)
    {
        sle = std::make_shared<SLE>(k);
        created = true;
    }
    else
    {
        hashes = static_cast<decltype(hashes)>(sle->getFieldV256(sfHashes));
        created = false;
    }
    XRPL_ASSERT(hashes.size() <= 256, "xrpl::Ledger::updateSkipList : second maximum hashes size");
    if (hashes.size() == 256)
        hashes.erase(hashes.begin());
    hashes.push_back(header_.parentHash);
    sle->setFieldV256(sfHashes, STVector256(hashes));
    sle->setFieldU32(sfLastLedgerSequence, prevIndex);
    if (created)
    {
        rawInsert(sle);
    }
    else
    {
        rawReplace(sle);
    }
}
 
bool
Ledger::isFlagLedger() const
{
    return ::xrpl::isFlagLedger(header_.seq);
}
bool
Ledger::isVotingLedger() const
{
    return ::xrpl::isVotingLedger(header_.seq + 1);
}
 
void
Ledger::unshare() const
{
    stateMap_.unshare();
    txMap_.unshare();
}
 
void
Ledger::invariants() const
{
    stateMap_.invariants();
    txMap_.invariants();
}
 
}  // namespace xrpl