AmendmentTable.cpp

#include <xrpld/app/main/Application.h>
#include <xrpld/app/misc/AmendmentTable.h>
#include <xrpld/app/rdb/Wallet.h>
#include <xrpld/core/ConfigSections.h>
 
#include <xrpl/protocol/Feature.h>
#include <xrpl/protocol/STValidation.h>
#include <xrpl/protocol/TxFlags.h>
#include <xrpl/protocol/jss.h>
 
#include <boost/algorithm/string.hpp>
#include <boost/format.hpp>
#include <boost/range/adaptor/transformed.hpp>
#include <boost/regex.hpp>
 
#include <algorithm>
#include <mutex>
 
namespace ripple {
 
static std::vector<std::pair<uint256, std::string>>
parseSection(Section const& section)
{
    static boost::regex const re1(
        "^"                        // start of line
        "(?:\\s*)"                 // whitespace (optional)
        "([abcdefABCDEF0-9]{64})"  // <hexadecimal amendment ID>
        "(?:\\s+)"                 // whitespace
        "(\\S+)"                   // <description>
        ,
        boost::regex_constants::optimize);
 
    std::vector<std::pair<uint256, std::string>> names;
 
    for (auto const& line : section.lines())
    {
        boost::smatch match;
 
        if (!boost::regex_match(line, match, re1))
            Throw<std::runtime_error>(
                "Invalid entry '" + line + "' in [" + section.name() + "]");
 
        uint256 id;
 
        if (!id.parseHex(match[1]))
            Throw<std::runtime_error>(
                "Invalid amendment ID '" + match[1] + "' in [" +
                section.name() + "]");
 
        names.push_back(std::make_pair(id, match[2]));
    }
 
    return names;
}
 
class TrustedVotes
{
private:
    // Associates each trusted validator with the last votes we saw from them
    // and an expiration for that record.
    struct UpvotesAndTimeout
    {
        std::vector<uint256> upVotes;
        std::optional<NetClock::time_point> timeout;
    };
    hash_map<PublicKey, UpvotesAndTimeout> recordedVotes_;
 
public:
    TrustedVotes() = default;
    TrustedVotes(TrustedVotes const& rhs) = delete;
    TrustedVotes&
    operator=(TrustedVotes const& rhs) = delete;
 
    // Called when the list of trusted validators changes.
    //
    // Call with AmendmentTable::mutex_ locked.
    void
    trustChanged(
        hash_set<PublicKey> const& allTrusted,
        std::lock_guard<std::mutex> const& lock)
    {
        decltype(recordedVotes_) newRecordedVotes;
        newRecordedVotes.reserve(allTrusted.size());
 
        // Make sure every PublicKey in allTrusted is represented in
        // recordedVotes_.  Also make sure recordedVotes_ contains
        // no additional PublicKeys.
        for (auto& trusted : allTrusted)
        {
            if (recordedVotes_.contains(trusted))
            {
                // Preserve this validator's previously saved voting state.
                newRecordedVotes.insert(recordedVotes_.extract(trusted));
            }
            else
            {
                // New validators have a starting position of no on everything.
                // Add the entry with an empty vector and unseated timeout.
                newRecordedVotes[trusted];
            }
        }
        // The votes of any no-longer-trusted validators will be destroyed
        // when changedTrustedVotes goes out of scope.
        recordedVotes_.swap(newRecordedVotes);
    }
 
    // Called when we receive the latest votes.
    //
    // Call with AmendmentTable::mutex_ locked.
    void
    recordVotes(
        Rules const& rules,
        std::vector<std::shared_ptr<STValidation>> const& valSet,
        NetClock::time_point const closeTime,
        beast::Journal j,
        std::lock_guard<std::mutex> const& lock)
    {
        // When we get an STValidation we save the upVotes it contains, but
        // we also set an expiration for those upVotes.  The following constant
        // controls the timeout.
        //
        // There really is no "best" timeout to choose for when we finally
        // lose confidence that we know how a validator is voting.  But part
        // of the point of recording validator votes is to avoid flapping of
        // amendment votes.  A 24h timeout says that we will change the local
        // record of a validator's vote to "no" 24h after the last vote seen
        // from that validator.  So flapping due to that validator being off
        // line will happen less frequently than every 24 hours.
        using namespace std::chrono_literals;
        static constexpr NetClock::duration expiresAfter = 24h;
 
        auto const newTimeout = closeTime + expiresAfter;
 
        // Walk all validations and replace previous votes from trusted
        // validators with these newest votes.
        for (auto const& val : valSet)
        {
            auto const pkHuman =
                toBase58(TokenType::NodePublic, val->getSignerPublic());
            // If this validation comes from one of our trusted validators...
            if (auto const iter = recordedVotes_.find(val->getSignerPublic());
                iter != recordedVotes_.end())
            {
                iter->second.timeout = newTimeout;
                if (val->isFieldPresent(sfAmendments))
                {
                    auto const& choices = val->getFieldV256(sfAmendments);
                    iter->second.upVotes.assign(choices.begin(), choices.end());
                    JLOG(j.debug())
                        << "recordVotes: Validation from trusted " << pkHuman
                        << " has " << choices.size() << " amendment votes: "
                        << boost::algorithm::join(
                               iter->second.upVotes |
                                   boost::adaptors::transformed(
                                       to_string<256, void>),
                               ", ");
                    // TODO: Maybe transform using to_short_string once #5126 is
                    // merged
                    //
                    // iter->second.upVotes |
                    // boost::adaptors::transformed(to_short_string<256, void>)
                }
                else
                {
                    // This validator does not upVote any amendments right now.
                    iter->second.upVotes.clear();
                    JLOG(j.debug()) << "recordVotes: Validation from trusted "
                                    << pkHuman << " has no amendment votes.";
                }
            }
            else
            {
                JLOG(j.debug())
                    << "recordVotes: Ignoring validation from untrusted "
                    << pkHuman;
            }
        }
 
        // Now remove any expired records from recordedVotes_.
        std::for_each(
            recordedVotes_.begin(),
            recordedVotes_.end(),
            [&closeTime, newTimeout, &j](
                decltype(recordedVotes_)::value_type& votes) {
                auto const pkHuman =
                    toBase58(TokenType::NodePublic, votes.first);
                if (!votes.second.timeout)
                {
                    XRPL_ASSERT(
                        votes.second.upVotes.empty(),
                        "ripple::TrustedVotes::recordVotes : received no "
                        "upvotes");
                    JLOG(j.debug())
                        << "recordVotes: Have not received any "
                           "amendment votes from "
                        << pkHuman << " since last timeout or startup";
                }
                else if (closeTime > votes.second.timeout)
                {
                    JLOG(j.debug())
                        << "recordVotes: Timeout: Clearing votes from "
                        << pkHuman;
                    votes.second.timeout.reset();
                    votes.second.upVotes.clear();
                }
                else if (votes.second.timeout != newTimeout)
                {
                    XRPL_ASSERT(
                        votes.second.timeout < newTimeout,
                        "ripple::TrustedVotes::recordVotes : votes not "
                        "expired");
                    using namespace std::chrono;
                    auto const age = duration_cast<minutes>(
                        newTimeout - *votes.second.timeout);
                    JLOG(j.debug()) << "recordVotes: Using " << age.count()
                                    << "min old cached votes from " << pkHuman;
                }
            });
    }
 
    // Return the information needed by AmendmentSet to determine votes.
    //
    // Call with AmendmentTable::mutex_ locked.
    [[nodiscard]] std::pair<int, hash_map<uint256, int>>
    getVotes(Rules const& rules, std::lock_guard<std::mutex> const& lock) const
    {
        hash_map<uint256, int> ret;
        int available = 0;
        for (auto& validatorVotes : recordedVotes_)
        {
            XRPL_ASSERT(
                validatorVotes.second.timeout ||
                    validatorVotes.second.upVotes.empty(),
                "ripple::TrustedVotes::getVotes : valid votes");
            if (validatorVotes.second.timeout)
                ++available;
            for (uint256 const& amendment : validatorVotes.second.upVotes)
            {
                ret[amendment] += 1;
            }
        }
        return {available, ret};
    }
};
 
struct AmendmentState
{
    AmendmentVote vote = AmendmentVote::down;
 
    bool enabled = false;
 
    bool supported = false;
 
    std::string name;
 
    explicit AmendmentState() = default;
};
 
class AmendmentSet
{
private:
    // How many yes votes each amendment received
    hash_map<uint256, int> votes_;
    // number of trusted validations
    int trustedValidations_ = 0;
    // number of votes needed
    int threshold_ = 0;
 
public:
    AmendmentSet(
        Rules const& rules,
        TrustedVotes const& trustedVotes,
        std::lock_guard<std::mutex> const& lock)
    {
        // process validations for ledger before flag ledger.
        auto [trustedCount, newVotes] = trustedVotes.getVotes(rules, lock);
 
        trustedValidations_ = trustedCount;
        votes_.swap(newVotes);
 
        threshold_ = std::max(
            1L,
            static_cast<long>(
                (trustedValidations_ * amendmentMajorityCalcThreshold.num) /
                amendmentMajorityCalcThreshold.den));
    }
 
    bool
    passes(uint256 const& amendment) const
    {
        auto const& it = votes_.find(amendment);
 
        if (it == votes_.end())
            return false;
 
        // One validator is an exception, otherwise it is not possible
        // to gain majority.
        if (trustedValidations_ == 1)
            return it->second >= threshold_;
 
        return it->second > threshold_;
    }
 
    int
    votes(uint256 const& amendment) const
    {
        auto const& it = votes_.find(amendment);
 
        if (it == votes_.end())
            return 0;
 
        return it->second;
    }
 
    int
    trustedValidations() const
    {
        return trustedValidations_;
    }
 
    int
    threshold() const
    {
        return threshold_;
    }
};
 
//------------------------------------------------------------------------------
 
class AmendmentTableImpl final : public AmendmentTable
{
private:
    mutable std::mutex mutex_;
 
    hash_map<uint256, AmendmentState> amendmentMap_;
    std::uint32_t lastUpdateSeq_;
 
    // Record of the last votes seen from trusted validators.
    TrustedVotes previousTrustedVotes_;
 
    // Time that an amendment must hold a majority for
    std::chrono::seconds const majorityTime_;
 
    // The results of the last voting round - may be empty if
    // we haven't participated in one yet.
    std::unique_ptr<AmendmentSet> lastVote_;
 
    // True if an unsupported amendment is enabled
    bool unsupportedEnabled_;
 
    // Unset if no unsupported amendments reach majority,
    // else set to the earliest time an unsupported amendment
    // will be enabled.
    std::optional<NetClock::time_point> firstUnsupportedExpected_;
 
    beast::Journal const j_;
 
    // Database which persists veto/unveto vote
    DatabaseCon& db_;
 
    // Finds or creates state.  Must be called with mutex_ locked.
    AmendmentState&
    add(uint256 const& amendment, std::lock_guard<std::mutex> const& lock);
 
    // Finds existing state.  Must be called with mutex_ locked.
    AmendmentState*
    get(uint256 const& amendment, std::lock_guard<std::mutex> const& lock);
 
    AmendmentState const*
    get(uint256 const& amendment,
        std::lock_guard<std::mutex> const& lock) const;
 
    // Injects amendment json into v.  Must be called with mutex_ locked.
    void
    injectJson(
        Json::Value& v,
        uint256 const& amendment,
        AmendmentState const& state,
        bool isAdmin,
        std::lock_guard<std::mutex> const& lock) const;
 
    void
    persistVote(
        uint256 const& amendment,
        std::string const& name,
        AmendmentVote vote) const;
 
public:
    AmendmentTableImpl(
        Application& app,
        std::chrono::seconds majorityTime,
        std::vector<FeatureInfo> const& supported,
        Section const& enabled,
        Section const& vetoed,
        beast::Journal journal);
 
    uint256
    find(std::string const& name) const override;
 
    bool
    veto(uint256 const& amendment) override;
    bool
    unVeto(uint256 const& amendment) override;
 
    bool
    enable(uint256 const& amendment) override;
 
    bool
    isEnabled(uint256 const& amendment) const override;
    bool
    isSupported(uint256 const& amendment) const override;
 
    bool
    hasUnsupportedEnabled() const override;
 
    std::optional<NetClock::time_point>
    firstUnsupportedExpected() const override;
 
    Json::Value
    getJson(bool isAdmin) const override;
    Json::Value
    getJson(uint256 const&, bool isAdmin) const override;
 
    bool
    needValidatedLedger(LedgerIndex seq) const override;
 
    void
    doValidatedLedger(
        LedgerIndex seq,
        std::set<uint256> const& enabled,
        majorityAmendments_t const& majority) override;
 
    void
    trustChanged(hash_set<PublicKey> const& allTrusted) override;
 
    std::vector<uint256>
    doValidation(std::set<uint256> const& enabledAmendments) const override;
 
    std::vector<uint256>
    getDesired() const override;
 
    std::map<uint256, std::uint32_t>
    doVoting(
        Rules const& rules,
        NetClock::time_point closeTime,
        std::set<uint256> const& enabledAmendments,
        majorityAmendments_t const& majorityAmendments,
        std::vector<std::shared_ptr<STValidation>> const& validations) override;
};
 
//------------------------------------------------------------------------------
 
AmendmentTableImpl::AmendmentTableImpl(
    Application& app,
    std::chrono::seconds majorityTime,
    std::vector<FeatureInfo> const& supported,
    Section const& enabled,
    Section const& vetoed,
    beast::Journal journal)
    : lastUpdateSeq_(0)
    , majorityTime_(majorityTime)
    , unsupportedEnabled_(false)
    , j_(journal)
    , db_(app.getWalletDB())
{
    std::lock_guard lock(mutex_);
 
    // Find out if the FeatureVotes table exists in WalletDB
    bool const featureVotesExist = [this]() {
        auto db = db_.checkoutDb();
        return createFeatureVotes(*db);
    }();
 
    // Parse supported amendments
    for (auto const& [name, amendment, votebehavior] : supported)
    {
        AmendmentState& s = add(amendment, lock);
 
        s.name = name;
        s.supported = true;
        switch (votebehavior)
        {
            case VoteBehavior::DefaultYes:
                s.vote = AmendmentVote::up;
                break;
 
            case VoteBehavior::DefaultNo:
                s.vote = AmendmentVote::down;
                break;
 
            case VoteBehavior::Obsolete:
                s.vote = AmendmentVote::obsolete;
                break;
        }
 
        JLOG(j_.debug()) << "Amendment " << amendment << " (" << s.name
                         << ") is supported and will be "
                         << (s.vote == AmendmentVote::up ? "up" : "down")
                         << " voted by default if not enabled on the ledger.";
    }
 
    hash_set<uint256> detect_conflict;
    // Parse enabled amendments from config
    for (std::pair<uint256, std::string> const& a : parseSection(enabled))
    {
        if (featureVotesExist)
        {  // If the table existed, warn about duplicate config info
            JLOG(j_.warn()) << "[amendments] section in config file ignored"
                               " in favor of data in db/wallet.db.";
            break;
        }
        else
        {  // Otherwise transfer config data into the table
            detect_conflict.insert(a.first);
            persistVote(a.first, a.second, AmendmentVote::up);
        }
    }
 
    // Parse vetoed amendments from config
    for (auto const& a : parseSection(vetoed))
    {
        if (featureVotesExist)
        {  // If the table existed, warn about duplicate config info
            JLOG(j_.warn())
                << "[veto_amendments] section in config file ignored"
                   " in favor of data in db/wallet.db.";
            break;
        }
        else
        {  // Otherwise transfer config data into the table
            if (detect_conflict.count(a.first) == 0)
            {
                persistVote(a.first, a.second, AmendmentVote::down);
            }
            else
            {
                JLOG(j_.warn())
                    << "[veto_amendments] section in config has amendment "
                    << '(' << a.first << ", " << a.second
                    << ") both [veto_amendments] and [amendments].";
            }
        }
    }
 
    // Read amendment votes from wallet.db
    auto db = db_.checkoutDb();
    readAmendments(
        *db,
        [&](boost::optional<std::string> amendment_hash,
            boost::optional<std::string> amendment_name,
            boost::optional<AmendmentVote> vote) {
            uint256 amend_hash;
            if (!amendment_hash || !amendment_name || !vote)
            {
                // These fields should never have nulls, but check
                Throw<std::runtime_error>(
                    "Invalid FeatureVotes row in wallet.db");
            }
            if (!amend_hash.parseHex(*amendment_hash))
            {
                Throw<std::runtime_error>(
                    "Invalid amendment ID '" + *amendment_hash +
                    " in wallet.db");
            }
            if (*vote == AmendmentVote::down)
            {
                // Unknown amendments are effectively vetoed already
                if (auto s = get(amend_hash, lock))
                {
                    JLOG(j_.info()) << "Amendment {" << *amendment_name << ", "
                                    << amend_hash << "} is downvoted.";
                    if (!amendment_name->empty())
                        s->name = *amendment_name;
                    // An obsolete amendment's vote can never be changed
                    if (s->vote != AmendmentVote::obsolete)
                        s->vote = *vote;
                }
            }
            else  // up-vote
            {
                AmendmentState& s = add(amend_hash, lock);
 
                JLOG(j_.debug()) << "Amendment {" << *amendment_name << ", "
                                 << amend_hash << "} is upvoted.";
                if (!amendment_name->empty())
                    s.name = *amendment_name;
                // An obsolete amendment's vote can never be changed
                if (s.vote != AmendmentVote::obsolete)
                    s.vote = *vote;
            }
        });
}
 
AmendmentState&
AmendmentTableImpl::add(
    uint256 const& amendmentHash,
    std::lock_guard<std::mutex> const&)
{
    // call with the mutex held
    return amendmentMap_[amendmentHash];
}
 
AmendmentState*
AmendmentTableImpl::get(
    uint256 const& amendmentHash,
    std::lock_guard<std::mutex> const& lock)
{
    // Forward to the const version of get.
    return const_cast<AmendmentState*>(
        std::as_const(*this).get(amendmentHash, lock));
}
 
AmendmentState const*
AmendmentTableImpl::get(
    uint256 const& amendmentHash,
    std::lock_guard<std::mutex> const&) const
{
    // call with the mutex held
    auto ret = amendmentMap_.find(amendmentHash);
 
    if (ret == amendmentMap_.end())
        return nullptr;
 
    return &ret->second;
}
 
uint256
AmendmentTableImpl::find(std::string const& name) const
{
    std::lock_guard lock(mutex_);
 
    for (auto const& e : amendmentMap_)
    {
        if (name == e.second.name)
            return e.first;
    }
 
    return {};
}
 
void
AmendmentTableImpl::persistVote(
    uint256 const& amendment,
    std::string const& name,
    AmendmentVote vote) const
{
    XRPL_ASSERT(
        vote != AmendmentVote::obsolete,
        "ripple::AmendmentTableImpl::persistVote : valid vote input");
    auto db = db_.checkoutDb();
    voteAmendment(*db, amendment, name, vote);
}
 
bool
AmendmentTableImpl::veto(uint256 const& amendment)
{
    std::lock_guard lock(mutex_);
    AmendmentState& s = add(amendment, lock);
 
    if (s.vote != AmendmentVote::up)
        return false;
    s.vote = AmendmentVote::down;
    persistVote(amendment, s.name, s.vote);
    return true;
}
 
bool
AmendmentTableImpl::unVeto(uint256 const& amendment)
{
    std::lock_guard lock(mutex_);
    AmendmentState* const s = get(amendment, lock);
 
    if (!s || s->vote != AmendmentVote::down)
        return false;
    s->vote = AmendmentVote::up;
    persistVote(amendment, s->name, s->vote);
    return true;
}
 
bool
AmendmentTableImpl::enable(uint256 const& amendment)
{
    std::lock_guard lock(mutex_);
    AmendmentState& s = add(amendment, lock);
 
    if (s.enabled)
        return false;
 
    s.enabled = true;
 
    if (!s.supported)
    {
        JLOG(j_.error()) << "Unsupported amendment " << amendment
                         << " activated.";
        unsupportedEnabled_ = true;
    }
 
    return true;
}
 
bool
AmendmentTableImpl::isEnabled(uint256 const& amendment) const
{
    std::lock_guard lock(mutex_);
    AmendmentState const* s = get(amendment, lock);
    return s && s->enabled;
}
 
bool
AmendmentTableImpl::isSupported(uint256 const& amendment) const
{
    std::lock_guard lock(mutex_);
    AmendmentState const* s = get(amendment, lock);
    return s && s->supported;
}
 
bool
AmendmentTableImpl::hasUnsupportedEnabled() const
{
    std::lock_guard lock(mutex_);
    return unsupportedEnabled_;
}
 
std::optional<NetClock::time_point>
AmendmentTableImpl::firstUnsupportedExpected() const
{
    std::lock_guard lock(mutex_);
    return firstUnsupportedExpected_;
}
 
std::vector<uint256>
AmendmentTableImpl::doValidation(std::set<uint256> const& enabled) const
{
    // Get the list of amendments we support and do not
    // veto, but that are not already enabled
    std::vector<uint256> amendments;
 
    {
        std::lock_guard lock(mutex_);
        amendments.reserve(amendmentMap_.size());
        for (auto const& e : amendmentMap_)
        {
            if (e.second.supported && e.second.vote == AmendmentVote::up &&
                (enabled.count(e.first) == 0))
            {
                amendments.push_back(e.first);
                JLOG(j_.info()) << "Voting for amendment " << e.second.name;
            }
        }
    }
 
    if (!amendments.empty())
        std::sort(amendments.begin(), amendments.end());
 
    return amendments;
}
 
std::vector<uint256>
AmendmentTableImpl::getDesired() const
{
    // Get the list of amendments we support and do not veto
    return doValidation({});
}
 
std::map<uint256, std::uint32_t>
AmendmentTableImpl::doVoting(
    Rules const& rules,
    NetClock::time_point closeTime,
    std::set<uint256> const& enabledAmendments,
    majorityAmendments_t const& majorityAmendments,
    std::vector<std::shared_ptr<STValidation>> const& valSet)
{
    JLOG(j_.trace()) << "voting at " << closeTime.time_since_epoch().count()
                     << ": " << enabledAmendments.size() << ", "
                     << majorityAmendments.size() << ", " << valSet.size();
 
    std::lock_guard lock(mutex_);
 
    // Keep a record of the votes we received.
    previousTrustedVotes_.recordVotes(rules, valSet, closeTime, j_, lock);
 
    // Tally the most recent votes.
    auto vote =
        std::make_unique<AmendmentSet>(rules, previousTrustedVotes_, lock);
    JLOG(j_.debug()) << "Counted votes from " << vote->trustedValidations()
                     << " valid trusted validations, threshold is: "
                     << vote->threshold();
 
    // Map of amendments to the action to be taken for each one. The action is
    // the value of the flags in the pseudo-transaction
    std::map<uint256, std::uint32_t> actions;
 
    // process all amendments we know of
    for (auto const& entry : amendmentMap_)
    {
        if (enabledAmendments.contains(entry.first))
        {
            JLOG(j_.trace()) << entry.first << ": amendment already enabled";
 
            continue;
        }
 
        bool const hasValMajority = vote->passes(entry.first);
 
        auto const majorityTime = [&]() -> std::optional<NetClock::time_point> {
            auto const it = majorityAmendments.find(entry.first);
            if (it != majorityAmendments.end())
                return it->second;
            return std::nullopt;
        }();
 
        bool const hasLedgerMajority = majorityTime.has_value();
 
        auto const logStr = [&entry, &vote]() {
            std::stringstream ss;
            ss << entry.first << " (" << entry.second.name << ") has "
               << vote->votes(entry.first) << " votes";
            return ss.str();
        }();
 
        if (hasValMajority && !hasLedgerMajority &&
            entry.second.vote == AmendmentVote::up)
        {
            // Ledger says no majority, validators say yes, and voting yes
            // locally
            JLOG(j_.debug()) << logStr << ": amendment got majority";
            actions[entry.first] = tfGotMajority;
        }
        else if (!hasValMajority && hasLedgerMajority)
        {
            // Ledger says majority, validators say no
            JLOG(j_.debug()) << logStr << ": amendment lost majority";
            actions[entry.first] = tfLostMajority;
        }
        else if (
            hasLedgerMajority &&
            ((*majorityTime + majorityTime_) <= closeTime) &&
            entry.second.vote == AmendmentVote::up)
        {
            // Ledger says majority held
            JLOG(j_.debug()) << logStr << ": amendment majority held";
            actions[entry.first] = 0;
        }
        // Logging only below this point
        else if (hasValMajority && hasLedgerMajority)
        {
            JLOG(j_.debug())
                << logStr
                << ": amendment holding majority, waiting to be enabled";
        }
        else if (!hasValMajority)
        {
            JLOG(j_.debug()) << logStr << ": amendment does not have majority";
        }
    }
 
    // Stash for reporting
    lastVote_ = std::move(vote);
    return actions;
}
 
bool
AmendmentTableImpl::needValidatedLedger(LedgerIndex ledgerSeq) const
{
    std::lock_guard lock(mutex_);
 
    // Is there a ledger in which an amendment could have been enabled
    // between these two ledger sequences?
 
    return ((ledgerSeq - 1) / 256) != ((lastUpdateSeq_ - 1) / 256);
}
 
void
AmendmentTableImpl::doValidatedLedger(
    LedgerIndex ledgerSeq,
    std::set<uint256> const& enabled,
    majorityAmendments_t const& majority)
{
    for (auto& e : enabled)
        enable(e);
 
    std::lock_guard lock(mutex_);
 
    // Remember the ledger sequence of this update.
    lastUpdateSeq_ = ledgerSeq;
 
    // Since we have the whole list in `majority`, reset the time flag, even
    // if it's currently set. If it's not set when the loop is done, then any
    // prior unknown amendments have lost majority.
    firstUnsupportedExpected_.reset();
    for (auto const& [hash, time] : majority)
    {
        AmendmentState& s = add(hash, lock);
 
        if (s.enabled)
            continue;
 
        if (!s.supported)
        {
            JLOG(j_.info()) << "Unsupported amendment " << hash
                            << " reached majority at " << to_string(time);
            if (!firstUnsupportedExpected_ || firstUnsupportedExpected_ > time)
                firstUnsupportedExpected_ = time;
        }
    }
    if (firstUnsupportedExpected_)
        firstUnsupportedExpected_ = *firstUnsupportedExpected_ + majorityTime_;
}
 
void
AmendmentTableImpl::trustChanged(hash_set<PublicKey> const& allTrusted)
{
    std::lock_guard lock(mutex_);
    previousTrustedVotes_.trustChanged(allTrusted, lock);
}
 
void
AmendmentTableImpl::injectJson(
    Json::Value& v,
    uint256 const& id,
    AmendmentState const& fs,
    bool isAdmin,
    std::lock_guard<std::mutex> const&) const
{
    if (!fs.name.empty())
        v[jss::name] = fs.name;
 
    v[jss::supported] = fs.supported;
    if (!fs.enabled && isAdmin)
    {
        if (fs.vote == AmendmentVote::obsolete)
            v[jss::vetoed] = "Obsolete";
        else
            v[jss::vetoed] = fs.vote == AmendmentVote::down;
    }
    v[jss::enabled] = fs.enabled;
 
    if (!fs.enabled && lastVote_ && isAdmin)
    {
        auto const votesTotal = lastVote_->trustedValidations();
        auto const votesNeeded = lastVote_->threshold();
        auto const votesFor = lastVote_->votes(id);
 
        v[jss::count] = votesFor;
        v[jss::validations] = votesTotal;
 
        if (votesNeeded)
            v[jss::threshold] = votesNeeded;
    }
}
 
Json::Value
AmendmentTableImpl::getJson(bool isAdmin) const
{
    Json::Value ret(Json::objectValue);
    {
        std::lock_guard lock(mutex_);
        for (auto const& e : amendmentMap_)
        {
            injectJson(
                ret[to_string(e.first)] = Json::objectValue,
                e.first,
                e.second,
                isAdmin,
                lock);
        }
    }
    return ret;
}
 
Json::Value
AmendmentTableImpl::getJson(uint256 const& amendmentID, bool isAdmin) const
{
    Json::Value ret = Json::objectValue;
 
    {
        std::lock_guard lock(mutex_);
        AmendmentState const* a = get(amendmentID, lock);
        if (a)
        {
            Json::Value& jAmendment =
                (ret[to_string(amendmentID)] = Json::objectValue);
            injectJson(jAmendment, amendmentID, *a, isAdmin, lock);
        }
    }
 
    return ret;
}
 
std::unique_ptr<AmendmentTable>
make_AmendmentTable(
    Application& app,
    std::chrono::seconds majorityTime,
    std::vector<AmendmentTable::FeatureInfo> const& supported,
    Section const& enabled,
    Section const& vetoed,
    beast::Journal journal)
{
    return std::make_unique<AmendmentTableImpl>(
        app, majorityTime, supported, enabled, vetoed, journal);
}
 
}  // namespace ripple