BuildLedger.cpp

#include <xrpld/app/ledger/BuildLedger.h>
 
#include <xrpld/app/ledger/LedgerReplay.h>
#include <xrpld/app/ledger/OpenLedger.h>
#include <xrpld/app/main/Application.h>
 
#include <xrpl/basics/Log.h>
#include <xrpl/basics/chrono.h>
#include <xrpl/beast/utility/Journal.h>
#include <xrpl/beast/utility/instrumentation.h>
#include <xrpl/ledger/ApplyView.h>
#include <xrpl/ledger/CanonicalTXSet.h>
#include <xrpl/ledger/Ledger.h>
#include <xrpl/ledger/OpenView.h>
#include <xrpl/nodestore/NodeObject.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/LedgerHeader.h>
#include <xrpl/protocol/Protocol.h>
#include <xrpl/protocol/SystemParameters.h>
#include <xrpl/tx/apply.h>
 
#include <cstddef>
#include <exception>
#include <memory>
#include <set>
 
namespace xrpl {
 
/* Generic buildLedgerImpl that dispatches to ApplyTxs invocable with signature
    void(OpenView&, std::shared_ptr<Ledger> const&)
   It is responsible for adding transactions to the open view to generate the
   new ledger. It is generic since the mechanics differ for consensus
   generated ledgers versus replayed ledgers.
*/
template <class ApplyTxs>
std::shared_ptr<Ledger>
buildLedgerImpl(
    std::shared_ptr<Ledger const> const& parent,
    NetClock::time_point closeTime,
    bool const closeTimeCorrect,
    NetClock::duration closeResolution,
    Application& app,
    beast::Journal j,
    ApplyTxs&& applyTxs)
{
    auto built = std::make_shared<Ledger>(*parent, closeTime);
 
    if (built->isFlagLedger())
    {
        built->updateNegativeUNL();
    }
 
    // Set up to write SHAMap changes to our database,
    //   perform updates, extract changes
 
    {
        OpenView accum(&*built);
        XRPL_ASSERT(!accum.open(), "xrpl::buildLedgerImpl : valid ledger state");
        applyTxs(accum, built);
        accum.apply(*built);
    }
 
    built->updateSkipList();
    {
        // Write the final version of all modified SHAMap
        // nodes to the node store to preserve the new LCL
 
        int const asf = built->stateMap().flushDirty(NodeObjectType::AccountNode);
        int const tmf = built->txMap().flushDirty(NodeObjectType::TransactionNode);
        JLOG(j.debug()) << "Flushed " << asf << " accounts and " << tmf << " transaction nodes";
    }
    built->unshare();
 
    // Accept ledger
    XRPL_ASSERT(
        built->header().seq < kXrpLedgerEarliestFees || built->read(keylet::feeSettings()),
        "xrpl::buildLedgerImpl : valid ledger fees");
    built->setAccepted(closeTime, closeResolution, closeTimeCorrect);
 
    return built;
}

 
std::size_t
applyTransactions(
    Application& app,
    std::shared_ptr<Ledger const> const& built,
    CanonicalTXSet& txns,
    std::set<TxID>& failed,
    OpenView& view,
    beast::Journal j)
{
    bool certainRetry = true;
    std::size_t count = 0;
 
    // Attempt to apply all of the retriable transactions
    for (int pass = 0; pass < LEDGER_TOTAL_PASSES; ++pass)
    {
        JLOG(j.debug()) << (certainRetry ? "Pass: " : "Final pass: ") << pass << " begins ("
                        << txns.size() << " transactions)";
        int changes = 0;
 
        auto it = txns.begin();
 
        while (it != txns.end())
        {
            auto const txid = it->first.getTXID();
 
            try
            {
                if (pass == 0 && built->txExists(txid))
                {
                    it = txns.erase(it);
                    continue;
                }
 
                switch (applyTransaction(app, view, *it->second, certainRetry, TapNone, j))
                {
                    case ApplyTransactionResult::Success:
                        it = txns.erase(it);
                        ++changes;
                        break;
 
                    case ApplyTransactionResult::Fail:
                        failed.insert(txid);
                        it = txns.erase(it);
                        break;
 
                    case ApplyTransactionResult::Retry:
                        ++it;
                }
            }
            catch (std::exception const& ex)
            {
                JLOG(j.warn()) << "Transaction " << txid << " throws: " << ex.what();
                failed.insert(txid);
                it = txns.erase(it);
            }
        }
 
        JLOG(j.debug()) << (certainRetry ? "Pass: " : "Final pass: ") << pass << " completed ("
                        << changes << " changes)";
 
        // Accumulate changes.
        count += changes;
 
        // A non-retry pass made no changes
        if ((changes == 0) && !certainRetry)
            break;
 
        // Stop retriable passes
        if ((changes == 0) || (pass >= LEDGER_RETRY_PASSES))
            certainRetry = false;
    }
 
    // If there are any transactions left, we must have
    // tried them in at least one final pass
    XRPL_ASSERT(txns.empty() || !certainRetry, "xrpl::applyTransactions : retry transactions");
    return count;
}
 
// Build a ledger from consensus transactions
std::shared_ptr<Ledger>
buildLedger(
    std::shared_ptr<Ledger const> const& parent,
    NetClock::time_point closeTime,
    bool const closeTimeCorrect,
    NetClock::duration closeResolution,
    Application& app,
    CanonicalTXSet& txns,
    std::set<TxID>& failedTxns,
    beast::Journal j)
{
    JLOG(j.debug()) << "Report: Transaction Set = " << txns.key() << ", close "
                    << closeTime.time_since_epoch().count()
                    << (closeTimeCorrect ? "" : " (incorrect)");
 
    return buildLedgerImpl(
        parent,
        closeTime,
        closeTimeCorrect,
        closeResolution,
        app,
        j,
        [&](OpenView& accum, std::shared_ptr<Ledger> const& built) {
            JLOG(j.debug()) << "Attempting to apply " << txns.size() << " transactions";
 
            auto const applied = applyTransactions(app, built, txns, failedTxns, accum, j);
 
            if (!txns.empty() || !failedTxns.empty())
            {
                JLOG(j.debug()) << "Applied " << applied << " transactions; " << failedTxns.size()
                                << " failed and " << txns.size() << " will be retried. "
                                << "Total transactions in ledger (including Inner Batch): "
                                << accum.txCount();
            }
            else
            {
                JLOG(j.debug()) << "Applied " << applied << " transactions. "
                                << "Total transactions in ledger (including Inner Batch): "
                                << accum.txCount();
            }
        });
}
 
// Build a ledger by replaying
std::shared_ptr<Ledger>
buildLedger(
    LedgerReplay const& replayData,
    ApplyFlags applyFlags,
    Application& app,
    beast::Journal j)
{
    auto const& replayLedger = replayData.replay();
 
    JLOG(j.debug()) << "Report: Replay Ledger " << replayLedger->header().hash;
 
    return buildLedgerImpl(
        replayData.parent(),
        replayLedger->header().closeTime,
        ((replayLedger->header().closeFlags & kSLcfNoConsensusTime) == 0),
        replayLedger->header().closeTimeResolution,
        app,
        j,
        [&](OpenView& accum, std::shared_ptr<Ledger> const& built) {
            for (auto& tx : replayData.orderedTxns())
                applyTransaction(app, accum, *tx.second, false, applyFlags, j);
        });
}
 
}  // namespace xrpl