C++ STAmount类代码示例

TER SetTrust::doApply ()
{
    TER terResult = tesSUCCESS;

    STAmount const saLimitAmount (mTxn.getFieldAmount (sfLimitAmount));
    bool const bQualityIn (mTxn.isFieldPresent (sfQualityIn));
    bool const bQualityOut (mTxn.isFieldPresent (sfQualityOut));

    Currency const currency (saLimitAmount.getCurrency ());
    Account uDstAccountID (saLimitAmount.getIssuer ());

    // true, iff current is high account.
    bool const bHigh = mTxnAccountID > uDstAccountID;

    std::uint32_t uQualityIn (bQualityIn ? mTxn.getFieldU32 (sfQualityIn) : 0);
    std::uint32_t uQualityOut (bQualityOut ? mTxn.getFieldU32 (sfQualityOut) : 0);

    if (!saLimitAmount.isLegalNet ())
        return temBAD_AMOUNT;

    if (bQualityIn && QUALITY_ONE == uQualityIn)
        uQualityIn = 0;

    if (bQualityOut && QUALITY_ONE == uQualityOut)
        uQualityOut = 0;

    std::uint32_t const uTxFlags = mTxn.getFlags ();

    if (uTxFlags & tfTrustSetMask)
    {
        m_journal.trace <<
            "Malformed transaction: Invalid flags set.";
        return temINVALID_FLAG;
    }

    bool const bSetAuth = (uTxFlags & tfSetfAuth);
    bool const bSetNoRipple = (uTxFlags & tfSetNoRipple);
    bool const bClearNoRipple  = (uTxFlags & tfClearNoRipple);
    bool const bSetFreeze = (uTxFlags & tfSetFreeze);
    bool const bClearFreeze = (uTxFlags & tfClearFreeze);

    if (bSetAuth && !(mTxnAccount->getFieldU32 (sfFlags) & lsfRequireAuth))
    {
        m_journal.trace <<
            "Retry: Auth not required.";
        return tefNO_AUTH_REQUIRED;
    }

    if (saLimitAmount.isNative ())
    {
        m_journal.trace <<
            "Malformed transaction: Native credit limit: " <<
            saLimitAmount.getFullText ();
        return temBAD_LIMIT;
    }

    if (saLimitAmount < zero)
    {
        m_journal.trace <<
            "Malformed transaction: Negative credit limit.";
        return temBAD_LIMIT;
    }

    // Check if destination makes sense.
    if (!uDstAccountID || uDstAccountID == noAccount())
    {
        m_journal.trace <<
            "Malformed transaction: Destination account not specified.";

        return temDST_NEEDED;
    }

    if (mTxnAccountID == uDstAccountID)
    {
        SLE::pointer selDelete (
            mEngine->entryCache (ltRIPPLE_STATE,
                Ledger::getRippleStateIndex (
                    mTxnAccountID, uDstAccountID, currency)));

        if (selDelete)
        {
            m_journal.warning <<
                "Clearing redundant line.";

            return mEngine->view ().trustDelete (
                selDelete, mTxnAccountID, uDstAccountID);
        }
        else
        {
            m_journal.trace <<
                "Malformed transaction: Can not extend credit to self.";
            return temDST_IS_SRC;
        }
    }

    SLE::pointer sleDst (mEngine->entryCache (
        ltACCOUNT_ROOT, Ledger::getAccountRootIndex (uDstAccountID)));

    if (!sleDst)
    {
//.........这里部分代码省略.........

TER PathCursor::reverseLiquidityForAccount () const
{
    TER terResult = tesSUCCESS;
    auto const lastNodeIndex = nodeSize () - 1;
    auto const isFinalNode = (nodeIndex_ == lastNodeIndex);

    // 0 quality means none has yet been determined.
    std::uint64_t uRateMax = 0;

    // Current is allowed to redeem to next.
    const bool previousNodeIsAccount = !nodeIndex_ ||
            previousNode().isAccount();

    const bool nextNodeIsAccount = isFinalNode || nextNode().isAccount();

    AccountID const& previousAccountID = previousNodeIsAccount
        ? previousNode().account_ : node().account_;
    AccountID const& nextAccountID = nextNodeIsAccount ? nextNode().account_
        : node().account_;   // Offers are always issue.

    // This is the quality from from the previous node to this one.
    auto const qualityIn
         = (nodeIndex_ != 0)
            ? quality_in (view(),
                node().account_,
                previousAccountID,
                node().issue_.currency)
            : parityRate;

    // And this is the quality from the next one to this one.
    auto const qualityOut
        = (nodeIndex_ != lastNodeIndex)
            ? quality_out (view(),
                node().account_,
                nextAccountID,
                node().issue_.currency)
            : parityRate;

    // For previousNodeIsAccount:
    // Previous account is already owed.
    const STAmount saPrvOwed = (previousNodeIsAccount && nodeIndex_ != 0)
        ? creditBalance (view(),
            node().account_,
            previousAccountID,
            node().issue_.currency)
        : STAmount (node().issue_);

    // The limit amount that the previous account may owe.
    const STAmount saPrvLimit = (previousNodeIsAccount && nodeIndex_ != 0)
        ? creditLimit (view(),
            node().account_,
            previousAccountID,
            node().issue_.currency)
        : STAmount (node().issue_);

    // Next account is owed.
    const STAmount saNxtOwed = (nextNodeIsAccount && nodeIndex_ != lastNodeIndex)
        ? creditBalance (view(),
            node().account_,
            nextAccountID,
            node().issue_.currency)
        : STAmount (node().issue_);

    JLOG (j_.trace())
        << "reverseLiquidityForAccount>"
        << " nodeIndex_=" << nodeIndex_ << "/" << lastNodeIndex
        << " previousAccountID=" << previousAccountID
        << " node.account_=" << node().account_
        << " nextAccountID=" << nextAccountID
        << " currency=" << node().issue_.currency
        << " qualityIn=" << qualityIn
        << " qualityOut=" << qualityOut
        << " saPrvOwed=" << saPrvOwed
        << " saPrvLimit=" << saPrvLimit;

    // Requests are computed to be the maximum flow possible.
    // Previous can redeem the owed IOUs it holds.
    const STAmount saPrvRedeemReq  = (saPrvOwed > beast::zero)
        ? saPrvOwed
        : STAmount (saPrvOwed.issue ());

    // Previous can issue up to limit minus whatever portion of limit already
    // used (not including redeemable amount) - another "maximum flow".
    const STAmount saPrvIssueReq = (saPrvOwed < beast::zero)
        ? saPrvLimit + saPrvOwed : saPrvLimit;

    // Precompute these values in case we have an order book.
    auto deliverCurrency = previousNode().saRevDeliver.getCurrency ();
    const STAmount saPrvDeliverReq (
        {deliverCurrency, previousNode().saRevDeliver.getIssuer ()}, -1);
    // -1 means unlimited delivery.

    // Set to zero, because we're trying to hit the previous node.
    auto saCurRedeemAct = node().saRevRedeem.zeroed();

    // Track the amount we actually redeem.
    auto saCurIssueAct = node().saRevIssue.zeroed();

    // For !nextNodeIsAccount
    auto saCurDeliverAct  = node().saRevDeliver.zeroed();
//.........这里部分代码省略.........

TER PaymentTransactor::doApply ()
{
    // Ripple if source or destination is non-native or if there are paths.
    std::uint32_t const uTxFlags = mTxn.getFlags ();
	//bool const bPartialPayment = is_bit_set(uTxFlags, tfPartialPayment);
    bool const bLimitQuality = is_bit_set (uTxFlags, tfLimitQuality);
    bool const bNoRippleDirect = is_bit_set (uTxFlags, tfNoRippleDirect);
    bool const bPaths = mTxn.isFieldPresent (sfPaths);
    bool const bMax = mTxn.isFieldPresent (sfSendMax);
    uint160 const uDstAccountID = mTxn.getFieldAccount160 (sfDestination);
    STAmount const saDstAmount = mTxn.getFieldAmount (sfAmount);
    STAmount const saMaxAmount = bMax
                                   ? mTxn.getFieldAmount (sfSendMax)
                                   : saDstAmount.isNative ()
                                   ? saDstAmount
                                   : STAmount (saDstAmount.getCurrency (),
                                        mTxnAccountID,
                                        saDstAmount.getMantissa (),
                                        saDstAmount.getExponent (),
                                        saDstAmount < zero);
    uint160 const uSrcCurrency = saMaxAmount.getCurrency ();
    uint160 const uDstCurrency = saDstAmount.getCurrency ();
    bool const bSTRDirect = uSrcCurrency.isZero () && uDstCurrency.isZero ();

	
    m_journal.trace <<
        "saMaxAmount=" << saMaxAmount.getFullText () <<
        " saDstAmount=" << saDstAmount.getFullText ();

    if (!saDstAmount.isLegalNet () || !saMaxAmount.isLegalNet ())
        return temBAD_AMOUNT;

    if (uTxFlags & tfPaymentMask)
    {
        m_journal.trace <<
            "Malformed transaction: Invalid flags set.";

        return temINVALID_FLAG;
    }
    else if (!uDstAccountID)
    {
        m_journal.trace <<
            "Malformed transaction: Payment destination account not specified.";

        return temDST_NEEDED;
    }
    else if (bMax && saMaxAmount <= zero)
    {
        m_journal.trace <<
            "Malformed transaction: bad max amount: " << saMaxAmount.getFullText ();

        return temBAD_AMOUNT;
    }
    else if (saDstAmount <= zero)
    {
        m_journal.trace <<
            "Malformed transaction: bad dst amount: " << saDstAmount.getFullText ();

        return temBAD_AMOUNT;
    }
    else if (CURRENCY_BAD == uSrcCurrency || CURRENCY_BAD == uDstCurrency)
    {
        m_journal.trace <<
            "Malformed transaction: Bad currency.";

        return temBAD_CURRENCY;
    }
    else if (mTxnAccountID == uDstAccountID && uSrcCurrency == uDstCurrency && !bPaths)
    {
        m_journal.trace <<
            "Malformed transaction: Redundant transaction:" <<
            " src=" << to_string (mTxnAccountID) <<
            " dst=" << to_string (uDstAccountID) <<
            " src_cur=" << to_string (uSrcCurrency) <<
            " dst_cur=" << to_string (uDstCurrency);

        return temREDUNDANT;
    }
    else if (bMax && saMaxAmount == saDstAmount && saMaxAmount.getCurrency () == saDstAmount.getCurrency ())
    {
        m_journal.trace <<
            "Malformed transaction: Redundant SendMax.";

        return temREDUNDANT_SEND_MAX;
    }
    else if (bSTRDirect && bMax)
    {
        m_journal.trace <<
            "Malformed transaction: SendMax specified for STR to STR.";

        return temBAD_SEND_STR_MAX;
    }
    else if (bSTRDirect && bPaths)
    {
        m_journal.trace <<
            "Malformed transaction: Paths specified for STR to STR.";

        return temBAD_SEND_STR_PATHS;
    }
    else if (bSTRDirect && bLimitQuality)
//.........这里部分代码省略.........

TER
SetTrust::doApply ()
{
    TER terResult = tesSUCCESS;

    STAmount const saLimitAmount (tx().getFieldAmount (sfLimitAmount));
    bool const bQualityIn (tx().isFieldPresent (sfQualityIn));
    bool const bQualityOut (tx().isFieldPresent (sfQualityOut));

    Currency const currency (saLimitAmount.getCurrency ());
    AccountID uDstAccountID (saLimitAmount.getIssuer ());

    // true, iff current is high account.
    bool const bHigh = account_ > uDstAccountID;

    auto const sle = view().peek(
        keylet::account(account_));

    std::uint32_t const uOwnerCount = sle->getFieldU32 (sfOwnerCount);

    // The reserve required to create the line. Note that we allow up to
    // two trust lines without requiring a reserve because being able to
    // exchange currencies is a powerful Ripple feature.
    //
    // This is also a security feature: if you're a gateway and you want to
    // be able to let someone use your services, you would otherwise have to
    // give them enough XRP to cover the incremental reserve for their trust
    // line. If they had no intention of using your services, they could use
    // the XRP for their own purposes. So we make it possible for gateways
    // to fund accounts in a way where there's no incentive to trick them
    // into creating an account you have no intention of using.

    XRPAmount const reserveCreate ((uOwnerCount < 2)
        ? XRPAmount (zero)
        : view().fees().accountReserve(uOwnerCount + 1));

    std::uint32_t uQualityIn (bQualityIn ? tx().getFieldU32 (sfQualityIn) : 0);
    std::uint32_t uQualityOut (bQualityOut ? tx().getFieldU32 (sfQualityOut) : 0);

    if (bQualityOut && QUALITY_ONE == uQualityOut)
        uQualityOut = 0;

    std::uint32_t const uTxFlags = tx().getFlags ();

    bool const bSetAuth = (uTxFlags & tfSetfAuth);
    bool const bSetNoRipple = (uTxFlags & tfSetNoRipple);
    bool const bClearNoRipple  = (uTxFlags & tfClearNoRipple);
    bool const bSetFreeze = (uTxFlags & tfSetFreeze);
    bool const bClearFreeze = (uTxFlags & tfClearFreeze);

    auto viewJ = ctx_.app.journal ("View");

    if (bSetAuth && !(sle->getFieldU32 (sfFlags) & lsfRequireAuth))
    {
        j_.trace <<
            "Retry: Auth not required.";
        return tefNO_AUTH_REQUIRED;
    }

    if (account_ == uDstAccountID)
    {
        // The only purpose here is to allow a mistakenly created
        // trust line to oneself to be deleted. If no such trust
        // lines exist now, why not remove this code and simply
        // return an error?
        SLE::pointer sleDelete = view().peek (
            keylet::line(account_, uDstAccountID, currency));

        if (sleDelete)
        {
            j_.warning <<
                "Clearing redundant line.";

            return trustDelete (view(),
                sleDelete, account_, uDstAccountID, viewJ);
        }
        else
        {
            j_.trace <<
                "Malformed transaction: Can not extend credit to self.";
            return temDST_IS_SRC;
        }
    }

    SLE::pointer sleDst =
        view().peek (keylet::account(uDstAccountID));

    if (!sleDst)
    {
        j_.trace <<
            "Delay transaction: Destination account does not exist.";
        return tecNO_DST;
    }

    STAmount saLimitAllow = saLimitAmount;
    saLimitAllow.setIssuer (account_);

    SLE::pointer sleRippleState = view().peek (
        keylet::line(account_, uDstAccountID, currency));

//.........这里部分代码省略.........

// Make sure an offer is still valid. If not, mark it unfunded.
bool OfferCreateTransactor::bValidOffer (
    SLE::ref            sleOffer,
    uint256 const&      uOfferIndex,
    const uint160&      uOfferOwnerID,
    const STAmount&     saOfferPays,
    const STAmount&     saOfferGets,
    const uint160&      uTakerAccountID,
    boost::unordered_set<uint256>&  usOfferUnfundedFound,
    boost::unordered_set<uint256>&  usOfferUnfundedBecame,
    boost::unordered_set<uint160>&  usAccountTouched,
    STAmount&           saOfferFunds)                       // <--
{
    bool bValid = false;

    if (sleOffer->isFieldPresent (sfExpiration) && sleOffer->getFieldU32 (sfExpiration) <= mEngine->getLedger ()->getParentCloseTimeNC ())
    {
        // Offer is expired. Expired offers are considered unfunded. Delete it.
        WriteLog (lsINFO, OfferCreateTransactor) << "bValidOffer: encountered expired offer";

        usOfferUnfundedFound.insert (uOfferIndex);

        bValid  = false;
    }
    else if (uOfferOwnerID == uTakerAccountID)
    {
        // Would take own offer. Consider old offer expired. Delete it.
        WriteLog (lsINFO, OfferCreateTransactor) << "bValidOffer: encountered taker's own old offer";

        usOfferUnfundedFound.insert (uOfferIndex);

        bValid  = false;
    }
    else if (!saOfferGets.isPositive () || !saOfferPays.isPositive ())
    {
        // Offer has bad amounts. Consider offer expired. Delete it.
        WriteLog (lsWARNING, OfferCreateTransactor) << boost::str (boost::format ("bValidOffer: BAD OFFER: saOfferPays=%s saOfferGets=%s")
                % saOfferPays % saOfferGets);

        usOfferUnfundedFound.insert (uOfferIndex);

        bValid = false;
    }
    else
    {
        WriteLog (lsTRACE, OfferCreateTransactor) << "bValidOffer: saOfferPays=" << saOfferPays.getFullText ();

        saOfferFunds    = mEngine->getNodes ().accountFunds (uOfferOwnerID, saOfferPays);

        if (!saOfferFunds.isPositive ())
        {
            // Offer is unfunded, possibly due to previous balance action.
            WriteLog (lsDEBUG, OfferCreateTransactor) << "bValidOffer: offer unfunded: delete";

            boost::unordered_set<uint160>::iterator account = usAccountTouched.find (uOfferOwnerID);

            if (account != usAccountTouched.end ())
            {
                // Previously touched account.
                usOfferUnfundedBecame.insert (uOfferIndex); // Delete unfunded offer on success.
            }
            else
            {
                // Never touched source account.
                usOfferUnfundedFound.insert (uOfferIndex);  // Delete found unfunded offer when possible.
            }

            bValid  = false;
        }
        else
        {
            bValid  = true;
        }
    }

    return bValid;
}

path::RippleCalc::Output
flow (
    PaymentSandbox& sb,
    STAmount const& deliver,
    AccountID const& src,
    AccountID const& dst,
    STPathSet const& paths,
    bool defaultPaths,
    bool partialPayment,
    bool ownerPaysTransferFee,
    boost::optional<Quality> const& limitQuality,
    boost::optional<STAmount> const& sendMax,
    beast::Journal j,
    path::detail::FlowDebugInfo* flowDebugInfo)
{
    Issue const srcIssue = [&] {
        if (sendMax)
            return sendMax->issue ();
        if (!isXRP (deliver.issue ().currency))
            return Issue (deliver.issue ().currency, src);
        return xrpIssue ();
    }();

    Issue const dstIssue = deliver.issue ();

    boost::optional<Issue> sendMaxIssue;
    if (sendMax)
        sendMaxIssue = sendMax->issue ();

    // convert the paths to a collection of strands. Each strand is the collection
    // of account->account steps and book steps that may be used in this payment.
    auto sr = toStrands (sb, src, dst, dstIssue, sendMaxIssue, paths,
        defaultPaths, ownerPaysTransferFee, j);

    if (sr.first != tesSUCCESS)
    {
        path::RippleCalc::Output result;
        result.setResult (sr.first);
        return result;
    }

    auto& strands = sr.second;

    if (j.trace())
    {
        j.trace() << "\nsrc: " << src << "\ndst: " << dst
            << "\nsrcIssue: " << srcIssue << "\ndstIssue: " << dstIssue;
        j.trace() << "\nNumStrands: " << strands.size ();
        for (auto const& curStrand : strands)
        {
            j.trace() << "NumSteps: " << curStrand.size ();
            for (auto const& step : curStrand)
            {
                j.trace() << '\n' << *step << '\n';
            }
        }
    }

    const bool srcIsXRP = isXRP (srcIssue.currency);
    const bool dstIsXRP = isXRP (dstIssue.currency);

    auto const asDeliver = toAmountSpec (deliver);

    // The src account may send either xrp or iou. The dst account may receive
    // either xrp or iou. Since XRP and IOU amounts are represented by different
    // types, use templates to tell `flow` about the amount types.
    if (srcIsXRP && dstIsXRP)
    {
        return finishFlow (sb, srcIssue, dstIssue,
            flow<XRPAmount, XRPAmount> (
                sb, strands, asDeliver.xrp, defaultPaths, partialPayment,
                limitQuality, sendMax, j, flowDebugInfo));
    }

    if (srcIsXRP && !dstIsXRP)
    {
        return finishFlow (sb, srcIssue, dstIssue,
            flow<XRPAmount, IOUAmount> (
                sb, strands, asDeliver.iou, defaultPaths, partialPayment,
                limitQuality, sendMax, j, flowDebugInfo));
    }

    if (!srcIsXRP && dstIsXRP)
    {
        return finishFlow (sb, srcIssue, dstIssue,
            flow<IOUAmount, XRPAmount> (
                sb, strands, asDeliver.xrp, defaultPaths, partialPayment,
                limitQuality, sendMax, j, flowDebugInfo));
    }

    assert (!srcIsXRP && !dstIsXRP);
    return finishFlow (sb, srcIssue, dstIssue,
        flow<IOUAmount, IOUAmount> (
            sb, strands, asDeliver.iou, defaultPaths, partialPayment,
            limitQuality, sendMax, j, flowDebugInfo));

}

static Json::Value signPayment(
    Json::Value const& params,
    Json::Value& tx_json,
    RippleAddress const& raSrcAddressID,
    RPCDetail::LedgerFacade& ledgerFacade,
    Role role)
{
    RippleAddress dstAccountID;

    if (!tx_json.isMember ("Amount"))
        return RPC::missing_field_error ("tx_json.Amount");

    STAmount amount;

    if (! amountFromJsonNoThrow (amount, tx_json ["Amount"]))
        return RPC::invalid_field_error ("tx_json.Amount");

    if (!tx_json.isMember ("Destination"))
        return RPC::missing_field_error ("tx_json.Destination");

    if (!dstAccountID.setAccountID (tx_json["Destination"].asString ()))
        return RPC::invalid_field_error ("tx_json.Destination");

    if (tx_json.isMember ("Paths") && params.isMember ("build_path"))
        return RPC::make_error (rpcINVALID_PARAMS,
            "Cannot specify both 'tx_json.Paths' and 'build_path'");

    if (!tx_json.isMember ("Paths")
        && tx_json.isMember ("Amount")
        && params.isMember ("build_path"))
    {
        // Need a ripple path.
        Currency uSrcCurrencyID;
        Account uSrcIssuerID;

        STAmount    saSendMax;

        if (tx_json.isMember ("SendMax"))
        {
            if (! amountFromJsonNoThrow (saSendMax, tx_json ["SendMax"]))
                return RPC::invalid_field_error ("tx_json.SendMax");
        }
        else
        {
            // If no SendMax, default to Amount with sender as issuer.
            saSendMax = amount;
            saSendMax.setIssuer (raSrcAddressID.getAccountID ());
        }

        if (saSendMax.isNative () && amount.isNative ())
            return RPC::make_error (rpcINVALID_PARAMS,
                "Cannot build XRP to XRP paths.");

        {
            LegacyPathFind lpf (role == Role::ADMIN);
            if (!lpf.isOk ())
                return rpcError (rpcTOO_BUSY);

            STPathSet spsPaths;
            STPath fullLiquidityPath;
            bool valid = ledgerFacade.findPathsForOneIssuer (
                dstAccountID,
                saSendMax.issue (),
                amount,
                getConfig ().PATH_SEARCH_OLD,
                4,  // iMaxPaths
                spsPaths,
                fullLiquidityPath);


            if (!valid)
            {
                WriteLog (lsDEBUG, RPCHandler)
                        << "transactionSign: build_path: No paths found.";
                return rpcError (rpcNO_PATH);
            }
            WriteLog (lsDEBUG, RPCHandler)
                    << "transactionSign: build_path: "
                    << spsPaths.getJson (0);

            if (!spsPaths.empty ())
                tx_json["Paths"] = spsPaths.getJson (0);
        }
    }
    return Json::Value();
}

TER computeReverseLiquidityForAccount (
    RippleCalc& rippleCalc,
    const unsigned int nodeIndex, PathState& pathState,
    const bool bMultiQuality)
{
    TER terResult = tesSUCCESS;
    auto const lastNodeIndex = pathState.nodes().size () - 1;
    auto const isFinalNode = (nodeIndex == lastNodeIndex);

    // 0 quality means none has yet been determined.
    std::uint64_t uRateMax = 0;

    auto& previousNode = pathState.nodes()[nodeIndex ? nodeIndex - 1 : 0];
    auto& node = pathState.nodes()[nodeIndex];
    auto& nextNode = pathState.nodes()[isFinalNode ? lastNodeIndex : nodeIndex + 1];

    // Current is allowed to redeem to next.
    const bool previousNodeIsAccount = !nodeIndex || previousNode.isAccount();
    const bool nextNodeIsAccount = isFinalNode || nextNode.isAccount();

    const uint160& previousAccountID = previousNodeIsAccount
        ? previousNode.account_ : node.account_;
    const uint160& nextAccountID = nextNodeIsAccount ? nextNode.account_
        : node.account_;   // Offers are always issue.

    // This is the quality from from the previous node to this one.
    const std::uint32_t uQualityIn
         = (nodeIndex != 0)
            ? rippleCalc.mActiveLedger.rippleQualityIn (
                node.account_, previousAccountID, node.currency_)
            : QUALITY_ONE;

    // And this is the quality from the next one to this one.
    const std::uint32_t uQualityOut
        = (nodeIndex != lastNodeIndex)
            ? rippleCalc.mActiveLedger.rippleQualityOut (
                node.account_, nextAccountID, node.currency_)
            : QUALITY_ONE;

    // For previousNodeIsAccount:
    // Previous account is already owed.
    const STAmount saPrvOwed = (previousNodeIsAccount && nodeIndex != 0)
        ? rippleCalc.mActiveLedger.rippleOwed (
            node.account_, previousAccountID, node.currency_)
        : STAmount (node.currency_, node.account_);

    // The limit amount that the previous account may owe.
    const STAmount saPrvLimit = (previousNodeIsAccount && nodeIndex != 0)
        ? rippleCalc.mActiveLedger.rippleLimit (
            node.account_, previousAccountID, node.currency_)
        : STAmount (node.currency_, node.account_);

    // Next account is owed.
    const STAmount saNxtOwed = (nextNodeIsAccount && nodeIndex != lastNodeIndex)
        ? rippleCalc.mActiveLedger.rippleOwed (
            node.account_, nextAccountID, node.currency_)
        : STAmount (node.currency_, node.account_);

    WriteLog (lsTRACE, RippleCalc)
        << "computeReverseLiquidityForAccount>"
        << " nodeIndex=%d/%d" << nodeIndex << "/" << lastNodeIndex
        << " previousAccountID=" << previousAccountID
        << " node.account_=" << node.account_
        << " nextAccountID=" << nextAccountID
        << " currency_=" << node.currency_
        << " uQualityIn=" << uQualityIn
        << " uQualityOut=" << uQualityOut
        << " saPrvOwed=" << saPrvOwed
        << " saPrvLimit=" << saPrvLimit;

    // Requests are computed to be the maximum flow possible.
    // Previous can redeem the owed IOUs it holds.
    const STAmount saPrvRedeemReq  = (saPrvOwed > zero)
        ? saPrvOwed
        : STAmount (saPrvOwed.getCurrency (), saPrvOwed.getIssuer ());

    // This is the amount we're actually going to be setting for the previous
    // node.
    STAmount& saPrvRedeemAct = previousNode.saRevRedeem;

    // Previous can issue up to limit minus whatever portion of limit already
    // used (not including redeemable amount) - another "maximum flow".
    const STAmount saPrvIssueReq = (saPrvOwed < zero)
        ? saPrvLimit + saPrvOwed : saPrvLimit;
    STAmount& saPrvIssueAct = previousNode.saRevIssue;

    // Precompute these values in case we have an order book.
    auto deliverCurrency = previousNode.saRevDeliver.getCurrency ();
    const STAmount saPrvDeliverReq (
        deliverCurrency, previousNode.saRevDeliver.getIssuer (), -1);
    // Unlimited delivery.

    STAmount&       saPrvDeliverAct = previousNode.saRevDeliver;

    // For nextNodeIsAccount
    const STAmount& saCurRedeemReq  = node.saRevRedeem;

    // Set to zero, because we're trying to hit the previous node.
    STAmount saCurRedeemAct (
        saCurRedeemReq.getCurrency (), saCurRedeemReq.getIssuer ());
//.........这里部分代码省略.........

// This interface is deprecated.
Json::Value doRipplePathFind (RPC::Context& context)
{
    RPC::LegacyPathFind lpf (context.role == Role::ADMIN);
    if (!lpf.isOk ())
        return rpcError (rpcTOO_BUSY);

    context.loadType = Resource::feeHighBurdenRPC;

    RippleAddress raSrc;
    RippleAddress raDst;
    STAmount saDstAmount;
    Ledger::pointer lpLedger;

    Json::Value jvResult;

    if (getConfig().RUN_STANDALONE ||
        context.params.isMember(jss::ledger) ||
        context.params.isMember(jss::ledger_index) ||
        context.params.isMember(jss::ledger_hash))
    {
        // The caller specified a ledger
        jvResult = RPC::lookupLedger (
            context.params, lpLedger, context.netOps);
        if (!lpLedger)
            return jvResult;
    }

    if (!context.params.isMember (jss::source_account))
    {
        jvResult = rpcError (rpcSRC_ACT_MISSING);
    }
    else if (!context.params[jss::source_account].isString ()
             || !raSrc.setAccountID (
                 context.params[jss::source_account].asString ()))
    {
        jvResult = rpcError (rpcSRC_ACT_MALFORMED);
    }
    else if (!context.params.isMember (jss::destination_account))
    {
        jvResult = rpcError (rpcDST_ACT_MISSING);
    }
    else if (!context.params[jss::destination_account].isString ()
             || !raDst.setAccountID (
                 context.params[jss::destination_account].asString ()))
    {
        jvResult = rpcError (rpcDST_ACT_MALFORMED);
    }
    else if (
        // Parse saDstAmount.
        !context.params.isMember (jss::destination_amount)
        || ! amountFromJsonNoThrow(saDstAmount, context.params[jss::destination_amount])
        || saDstAmount <= zero
        || (!isXRP(saDstAmount.getCurrency ())
            && (!saDstAmount.getIssuer () ||
                noAccount() == saDstAmount.getIssuer ())))
    {
        WriteLog (lsINFO, RPCHandler) << "Bad destination_amount.";
        jvResult    = rpcError (rpcINVALID_PARAMS);
    }
    else if (
        // Checks on source_currencies.
        context.params.isMember (jss::source_currencies)
        && (!context.params[jss::source_currencies].isArray ()
            || !context.params[jss::source_currencies].size ())
        // Don't allow empty currencies.
    )
    {
        WriteLog (lsINFO, RPCHandler) << "Bad source_currencies.";
        jvResult    = rpcError (rpcINVALID_PARAMS);
    }
    else
    {
        context.loadType = Resource::feeHighBurdenRPC;
        RippleLineCache::pointer cache;

        if (lpLedger)
        {
            // The caller specified a ledger
            lpLedger = std::make_shared<Ledger> (std::ref (*lpLedger), false);
            cache = std::make_shared<RippleLineCache>(lpLedger);
        }
        else
        {
            // The closed ledger is recent and any nodes made resident
            // have the best chance to persist
            lpLedger = context.netOps.getClosedLedger();
            cache = getApp().getPathRequests().getLineCache(lpLedger, false);
        }

        Json::Value     jvSrcCurrencies;

        if (context.params.isMember (jss::source_currencies))
        {
            jvSrcCurrencies = context.params[jss::source_currencies];
        }
        else
        {
            jvSrcCurrencies = buildSrcCurrencies(raSrc, cache);
        }
//.........这里部分代码省略.........

/** Fill in the fee on behalf of the client.
    This is called when the client does not explicitly specify the fee.
    The client may also put a ceiling on the amount of the fee. This ceiling
    is expressed as a multiplier based on the current ledger's fee schedule.

    JSON fields

    "Fee"   The fee paid by the transaction. Omitted when the client
            wants the fee filled in.

    "fee_mult_max"  A multiplier applied to the current ledger's transaction
                    fee that caps the maximum the fee server should auto fill.
                    If this optional field is not specified, then a default
                    multiplier is used.

    @param tx       The JSON corresponding to the transaction to fill in
    @param ledger   A ledger for retrieving the current fee schedule
    @param result   A JSON object for injecting error results, if any
    @param admin    `true` if this is called by an administrative endpoint.
*/
static void autofill_fee (
    Json::Value& request,
    RPCDetail::LedgerFacade& ledgerFacade,
    Json::Value& result,
    bool admin)
{
    Json::Value& tx (request["tx_json"]);
    if (tx.isMember ("Fee"))
        return;

    std::uint64_t feeByTrans = 0;
    if (tx.isMember("TransactionType") && tx["TransactionType"].asString() == "Payment")
    {
        if (!tx.isMember("Destination"))
        {
            RPC::inject_error (rpcINVALID_PARAMS, "no destination account", result);
            return;
        }
        Config d;
        std::string dstAccountID = tx["Destination"].asString();
        RippleAddress dstAddress;
        if (!dstAddress.setAccountID(dstAccountID))
        {
            RPC::inject_error (rpcINVALID_PARAMS, "invalid account id", result);
            return;
        }

        //dst account not exist yet, charge a fix amount of fee(0.01) for creating
        if (!ledgerFacade.isAccountExist(dstAddress.getAccountID()))
        {
            feeByTrans = d.FEE_DEFAULT_CREATE;
        }

        //if currency is native(VRP/VBC), charge 1/1000 of transfer amount,
        //otherwise charge a fix amount of fee(0.001)
        if (tx.isMember("Amount"))
        {
            STAmount amount;
            if (!amountFromJsonNoThrow(amount, tx["Amount"]))
            {
                RPC::inject_error (rpcINVALID_PARAMS, "wrong amount format", result);
                return;
            }
            feeByTrans += amount.isNative() ? amount.getNValue() * d.FEE_DEFAULT_RATE_NATIVE : d.FEE_DEFAULT_NONE_NATIVE;
        }
    }
    
    int mult = Tuning::defaultAutoFillFeeMultiplier;
    if (request.isMember ("fee_mult_max"))
    {
        if (request["fee_mult_max"].isNumeric ())
        {
            mult = request["fee_mult_max"].asInt();
        }
        else
        {
            RPC::inject_error (rpcHIGH_FEE, RPC::expected_field_message (
                "fee_mult_max", "a number"), result);
            return;
        }
    }

    // Default fee in fee units.
    std::uint64_t const feeDefault = getConfig().TRANSACTION_FEE_BASE;

    // Administrative endpoints are exempt from local fees.
    std::uint64_t const fee = ledgerFacade.scaleFeeLoad (feeDefault, admin);
    std::uint64_t const limit = mult * ledgerFacade.scaleFeeBase (feeDefault);

    if (fee > limit)
    {
        std::stringstream ss;
        ss <<
            "Fee of " << fee <<
            " exceeds the requested tx limit of " << limit;
        RPC::inject_error (rpcHIGH_FEE, ss.str(), result);
        return;
    }
    
    std::stringstream ss;
//.........这里部分代码省略.........

void rippleLiquidity (
    RippleCalc& rippleCalc,
    std::uint32_t const uQualityIn,
    std::uint32_t const uQualityOut,
    STAmount const& saPrvReq,   // --> in limit including fees, <0 = unlimited
    STAmount const& saCurReq,   // --> out limit
    STAmount& saPrvAct,  // <-> in limit including achieved so far: <-- <= -->
    STAmount& saCurAct,  // <-> out limit including achieved so far: <-- <= -->
    std::uint64_t& uRateMax)
{
    WriteLog (lsTRACE, RippleCalc)
        << "rippleLiquidity>"
        << " uQualityIn=" << uQualityIn
        << " uQualityOut=" << uQualityOut
        << " saPrvReq=" << saPrvReq
        << " saCurReq=" << saCurReq
        << " saPrvAct=" << saPrvAct
        << " saCurAct=" << saCurAct;

    // saCurAct was once zero in a production server.
    assert (saCurReq != zero);
    assert (saCurReq > zero);

    assert (saPrvReq.getCurrency () == saCurReq.getCurrency ());
    assert (saPrvReq.getCurrency () == saPrvAct.getCurrency ());
    assert (saPrvReq.getIssuer () == saPrvAct.getIssuer ());

    const bool bPrvUnlimited = (saPrvReq < zero);  // -1 means unlimited.

    // Unlimited stays unlimited - don't do calculations.

    // How much could possibly flow through the previous node?
    const STAmount saPrv = bPrvUnlimited ? saPrvReq : saPrvReq - saPrvAct;

    // How much could possibly flow through the current node?
    const STAmount  saCur = saCurReq - saCurAct;

    WriteLog (lsTRACE, RippleCalc)
        << "rippleLiquidity: "
        << " bPrvUnlimited=" << bPrvUnlimited
        << " saPrv=" << saPrv
        << " saCur=" << saCur;

    // If nothing can flow, we might as well not do any work.
    if (saPrv == zero || saCur == zero)
        return;

    if (uQualityIn >= uQualityOut)
    {
        // You're getting better quality than you asked for, so no fee.
        WriteLog (lsTRACE, RippleCalc) << "rippleLiquidity: No fees";

        // Only process if the current rate, 1:1, is not worse than the previous
        // rate, uRateMax - otherwise there is no flow.
        if (!uRateMax || STAmount::uRateOne <= uRateMax)
        {
            // Limit amount to transfer if need - the minimum of amount being
            // paid and the amount that's wanted.
            STAmount saTransfer = bPrvUnlimited ? saCur
                : std::min (saPrv, saCur);

            // In reverse, we want to propagate the limited cur to prv and set
            // actual cur.
            //
            // In forward, we want to propagate the limited prv to cur and set
            // actual prv.
            //
            // This is the actual flow.
            saPrvAct += saTransfer;
            saCurAct += saTransfer;

            // If no rate limit, set rate limit to avoid combining with
            // something with a worse rate.
            if (uRateMax == 0)
                uRateMax = STAmount::uRateOne;
        }
    }
    else
    {
        // If the quality is worse than the previous
        WriteLog (lsTRACE, RippleCalc) << "rippleLiquidity: Fee";

        std::uint64_t uRate = getRate (
            STAmount (uQualityOut), STAmount (uQualityIn));

        // If the next rate is at least as good as the current rate, process.
        if (!uRateMax || uRate <= uRateMax)
        {
            auto currency = saCur.getCurrency ();
            auto uCurIssuerID = saCur.getIssuer ();

            // current actual = current request * (quality out / quality in).
            auto numerator = mulRound (
                saCur, uQualityOut, {currency, uCurIssuerID}, true);
            // True means "round up" to get best flow.

            STAmount saCurIn = divRound (
                numerator, uQualityIn, {currency, uCurIssuerID}, true);

            WriteLog (lsTRACE, RippleCalc)
//.........这里部分代码省略.........

TER WalletAddTransactor::doApply ()
{
    std::uint32_t const uTxFlags = mTxn.getFlags ();

    if (uTxFlags & tfUniversalMask)
    {
        m_journal.trace <<
            "Malformed transaction: Invalid flags set.";

        return temINVALID_FLAG;
    }

    Blob const vucPubKey    = mTxn.getFieldVL (sfPublicKey);
    Blob const vucSignature = mTxn.getFieldVL (sfSignature);

    uint160 const uAuthKeyID (mTxn.getFieldAccount160 (sfRegularKey));
    RippleAddress const naMasterPubKey (
        RippleAddress::createAccountPublic (vucPubKey));
    uint160 const uDstAccountID (naMasterPubKey.getAccountID ());

    // FIXME: This should be moved to the transaction's signature check logic and cached
	if (!naMasterPubKey.verifySignature(
        Serializer::getSHA512Half (uAuthKeyID.begin (), uAuthKeyID.size ()), 
        vucSignature))
    {
        m_journal.trace <<
            "Unauthorized: bad signature ";
        return tefBAD_ADD_AUTH;
    }

    SLE::pointer sleDst (mEngine->entryCache (
        ltACCOUNT_ROOT, Ledger::getAccountRootIndex (uDstAccountID)));

    if (sleDst)
    {
        m_journal.trace <<
            "account already created";
        return tefCREATED;
    }

    // Direct STR payment.

    STAmount saDstAmount = mTxn.getFieldAmount (sfAmount);
    STAmount saPaid = mTxn.getTransactionFee ();
    STAmount const saSrcBalance = mTxnAccount->getFieldAmount (sfBalance);
    std::uint32_t const uOwnerCount = mTxnAccount->getFieldU32 (sfOwnerCount);
    std::uint64_t const uReserve = mEngine->getLedger ()->getReserve (uOwnerCount);
    

    // Make sure have enough reserve to send. Allow final spend to use reserve
    // for fee.
    // Note: Reserve is not scaled by fee.
    if (saSrcBalance + saPaid < saDstAmount + uReserve)
    {
        // Vote no. However, transaction might succeed, if applied in a
        // different order.
        m_journal.trace <<
            "Delay transaction: Insufficient funds: %s / %s (%d)" <<
            saSrcBalance.getText () << " / " <<
            (saDstAmount + uReserve).getText () << " with reserve = " <<
            uReserve;
        return tecUNFUNDED_ADD;
    }

    // Deduct initial balance from source account.
    mTxnAccount->setFieldAmount (sfBalance, saSrcBalance - saDstAmount);

    // Create the account.
    sleDst  = mEngine->entryCreate (ltACCOUNT_ROOT,
        Ledger::getAccountRootIndex (uDstAccountID));

    sleDst->setFieldAccount (sfAccount, uDstAccountID);
    sleDst->setFieldU32 (sfSequence, 1);
    sleDst->setFieldAmount (sfBalance, saDstAmount);
    sleDst->setFieldAccount (sfRegularKey, uAuthKeyID);

    return tesSUCCESS;
}

static Json::Value signPayment(
    Json::Value const& params,
    Json::Value& tx_json,
    RippleAddress const& raSrcAddressID,
    Ledger::pointer lSnapshot,
    int role)
{
    RippleAddress dstAccountID;

    if (!tx_json.isMember ("Amount"))
        return RPC::missing_field_error ("tx_json.Amount");

    STAmount amount;

    if (!amount.bSetJson (tx_json ["Amount"]))
        return RPC::invalid_field_error ("tx_json.Amount");

    if (!tx_json.isMember ("Destination"))
        return RPC::missing_field_error ("tx_json.Destination");

    if (!dstAccountID.setAccountID (tx_json["Destination"].asString ()))
        return RPC::invalid_field_error ("tx_json.Destination");

    if (tx_json.isMember ("Paths") && params.isMember ("build_path"))
        return RPC::make_error (rpcINVALID_PARAMS,
            "Cannot specify both 'tx_json.Paths' and 'tx_json.build_path'");

    if (!tx_json.isMember ("Paths")
        && tx_json.isMember ("Amount")
        && params.isMember ("build_path"))
    {
        // Need a ripple path.
        STPathSet   spsPaths;
        uint160     uSrcCurrencyID;
        uint160     uSrcIssuerID;

        STAmount    saSendMax;

        if (tx_json.isMember ("SendMax"))
        {
            if (!saSendMax.bSetJson (tx_json ["SendMax"]))
                return RPC::invalid_field_error ("tx_json.SendMax");
        }
        else
        {
            // If no SendMax, default to Amount with sender as issuer.
            saSendMax = amount;
            saSendMax.setIssuer (raSrcAddressID.getAccountID ());
        }

        if (saSendMax.isNative () && amount.isNative ())
            return RPC::make_error (rpcINVALID_PARAMS,
                "Cannot build STR to STR paths.");

        {
            LegacyPathFind lpf (role == Config::ADMIN);
            if (!lpf.isOk ())
                return rpcError (rpcTOO_BUSY);

            bool bValid;
            auto cache = boost::make_shared<RippleLineCache> (lSnapshot);
            Pathfinder pf (cache, raSrcAddressID, dstAccountID,
                           saSendMax.getCurrency (), saSendMax.getIssuer (),
                           amount, bValid);

            STPath extraPath;
            if (!bValid || !pf.findPaths (getConfig ().PATH_SEARCH_OLD, 4, spsPaths, extraPath))
            {
                WriteLog (lsDEBUG, RPCHandler)
                        << "transactionSign: build_path: No paths found.";
                return rpcError (rpcNO_PATH);
            }
            WriteLog (lsDEBUG, RPCHandler)
                    << "transactionSign: build_path: "
                    << spsPaths.getJson (0);

            if (!spsPaths.isEmpty ())
                tx_json["Paths"] = spsPaths.getJson (0);
        }
    }
    return Json::Value();
}

    TER doApply () override
    {
        // Ripple if source or destination is non-native or if there are paths.
        std::uint32_t const uTxFlags = mTxn.getFlags ();
        bool const partialPaymentAllowed = uTxFlags & tfPartialPayment;
        bool const limitQuality = uTxFlags & tfLimitQuality;
        bool const defaultPathsAllowed = !(uTxFlags & tfNoRippleDirect);
        bool const bPaths = mTxn.isFieldPresent (sfPaths);
        bool const bMax = mTxn.isFieldPresent (sfSendMax);
        Account const uDstAccountID (mTxn.getFieldAccount160 (sfDestination));
        STAmount const saDstAmount (mTxn.getFieldAmount (sfAmount));
        STAmount maxSourceAmount;
        if (bMax)
            maxSourceAmount = mTxn.getFieldAmount (sfSendMax);
        else if (saDstAmount.isNative ())
            maxSourceAmount = saDstAmount;
        else
          maxSourceAmount = STAmount (
              {saDstAmount.getCurrency (), mTxnAccountID},
              saDstAmount.mantissa(), saDstAmount.exponent (),
              saDstAmount < zero);
        auto const& uSrcCurrency = maxSourceAmount.getCurrency ();
        auto const& uDstCurrency = saDstAmount.getCurrency ();

        // isZero() is XRP.  FIX!
        bool const bXRPDirect = uSrcCurrency.isZero () && uDstCurrency.isZero ();

        m_journal.trace <<
            "maxSourceAmount=" << maxSourceAmount.getFullText () <<
            " saDstAmount=" << saDstAmount.getFullText ();

        if (!isLegalNet (saDstAmount) || !isLegalNet (maxSourceAmount))
            return temBAD_AMOUNT;

        if (uTxFlags & tfPaymentMask)
        {
            m_journal.trace <<
                "Malformed transaction: Invalid flags set.";

            return temINVALID_FLAG;
        }
        else if (!uDstAccountID)
        {
            m_journal.trace <<
                "Malformed transaction: Payment destination account not specified.";

            return temDST_NEEDED;
        }
        else if (bMax && maxSourceAmount <= zero)
        {
            m_journal.trace <<
                "Malformed transaction: bad max amount: " << maxSourceAmount.getFullText ();

            return temBAD_AMOUNT;
        }
        else if (saDstAmount <= zero)
        {
            m_journal.trace <<
                "Malformed transaction: bad dst amount: " << saDstAmount.getFullText ();

            return temBAD_AMOUNT;
        }
        else if (badCurrency() == uSrcCurrency || badCurrency() == uDstCurrency)
        {
            m_journal.trace <<
                "Malformed transaction: Bad currency.";

            return temBAD_CURRENCY;
        }
        else if (mTxnAccountID == uDstAccountID && uSrcCurrency == uDstCurrency && !bPaths)
        {
            // You're signing yourself a payment.
            // If bPaths is true, you might be trying some arbitrage.
            m_journal.trace <<
                "Malformed transaction: Redundant transaction:" <<
                " src=" << to_string (mTxnAccountID) <<
                " dst=" << to_string (uDstAccountID) <<
                " src_cur=" << to_string (uSrcCurrency) <<
                " dst_cur=" << to_string (uDstCurrency);

            return temREDUNDANT;
        }
        else if (bMax && maxSourceAmount == saDstAmount &&
                 maxSourceAmount.getCurrency () == saDstAmount.getCurrency ())
        {
            // Consistent but redundant transaction.
            m_journal.trace <<
                "Malformed transaction: Redundant SendMax.";

            return temREDUNDANT_SEND_MAX;
        }
        else if (bXRPDirect && bMax)
        {
            // Consistent but redundant transaction.
            m_journal.trace <<
                "Malformed transaction: SendMax specified for XRP to XRP.";

            return temBAD_SEND_XRP_MAX;
        }
        else if (bXRPDirect && bPaths)
//.........这里部分代码省略.........

// Take as much as possible. Adjusts account balances. Charges fees on top to taker.
// -->    uBookBase: The order book to take against.
// -->  saTakerPays: What the taker offers (w/ issuer)
// -->  saTakerGets: What the taker wanted (w/ issuer)
// <--  saTakerPaid: What taker could have paid including saved not including fees. To reduce an offer.
// <--   saTakerGot: What taker got not including fees. To reduce an offer.
// <--    terResult: tesSUCCESS, terNO_ACCOUNT, telFAILED_PROCESSING, or tecFAILED_PROCESSING
// <--    bUnfunded: if tesSUCCESS, consider offer unfunded after taking.
TER OfferCreateTransactor::takeOffers (
    const bool          bOpenLedger,
    const bool          bPassive,
    const bool          bSell,
    uint256 const&      uBookBase,
    const uint160&      uTakerAccountID,
    SLE::ref            sleTakerAccount,
    const STAmount&     saTakerPays,
    const STAmount&     saTakerGets,
    STAmount&           saTakerPaid,
    STAmount&           saTakerGot,
    bool&               bUnfunded)
{
    // The book has the most elements. Take the perspective of the book.
    // Book is ordered for taker: taker pays / taker gets (smaller is better)

    // The order is for the other books currencys for get and pays are opposites.
    // We want the same ratio for the respective currencies.
    // So we swap paid and gets for determing take quality.

    assert (saTakerPays && saTakerGets);

    WriteLog (lsDEBUG, OfferCreateTransactor) << "takeOffers: bSell: " << bSell << ": against book: " << uBookBase.ToString ();

    LedgerEntrySet&         lesActive           = mEngine->getNodes ();
    uint256                 uTipIndex           = uBookBase;
    const uint256           uBookEnd            = Ledger::getQualityNext (uBookBase);
    const uint64            uTakeQuality        = STAmount::getRate (saTakerGets, saTakerPays);
    STAmount                saTakerRate         = STAmount::setRate (uTakeQuality);
    const uint160           uTakerPaysAccountID = saTakerPays.getIssuer ();
    const uint160           uTakerGetsAccountID = saTakerGets.getIssuer ();
    TER                     terResult           = temUNCERTAIN;

    boost::unordered_set<uint256>   usOfferUnfundedBecame;  // Offers that became unfunded.
    boost::unordered_set<uint160>   usAccountTouched;       // Accounts touched.

    saTakerPaid     = STAmount (saTakerPays.getCurrency (), saTakerPays.getIssuer ());
    saTakerGot      = STAmount (saTakerGets.getCurrency (), saTakerGets.getIssuer ());
    bUnfunded       = false;

    while (temUNCERTAIN == terResult)
    {
        SLE::pointer    sleOfferDir;
        uint64          uTipQuality     = 0;
        STAmount        saTakerFunds    = lesActive.accountFunds (uTakerAccountID, saTakerPays);
        STAmount        saSubTakerPays  = saTakerPays - saTakerPaid; // How much more to spend.
        STAmount        saSubTakerGets  = saTakerGets - saTakerGot; // How much more is wanted.

        // Figure out next offer to take, if needed.
        if (saTakerFunds.isPositive ()          // Taker has funds available.
                && saSubTakerPays.isPositive ()
                && saSubTakerGets.isPositive ())
        {
            sleOfferDir     = mEngine->entryCache (ltDIR_NODE, lesActive.getNextLedgerIndex (uTipIndex, uBookEnd));

            if (sleOfferDir)
            {
                uTipIndex       = sleOfferDir->getIndex ();
                uTipQuality     = Ledger::getQuality (uTipIndex);

                WriteLog (lsDEBUG, OfferCreateTransactor) << boost::str (boost::format ("takeOffers: possible counter offer found: uTipQuality=%d uTipIndex=%s")
                        % uTipQuality
                        % uTipIndex.ToString ());

            }
            else
            {
                WriteLog (lsTRACE, OfferCreateTransactor) << "takeOffers: counter offer book is empty: "
                        << uTipIndex.ToString ()
                        << " ... "
                        << uBookEnd.ToString ();
            }
        }

        if (!saTakerFunds.isPositive ())                    // Taker has no funds.
        {
            // Done. Ran out of funds on previous round. As fees aren't calculated directly in this routine, funds are checked here.
            WriteLog (lsDEBUG, OfferCreateTransactor) << "takeOffers: done: taker unfunded.";

            bUnfunded   = true;                             // Don't create an order.
            terResult   = tesSUCCESS;
        }
        else if (!sleOfferDir                               // No offer directory to take.
                 || uTakeQuality < uTipQuality                   // No offers of sufficient quality available.
                 || (bPassive && uTakeQuality == uTipQuality))
        {
            // Done.
            STAmount    saTipRate           = sleOfferDir ? STAmount::setRate (uTipQuality) : saTakerRate;

            WriteLog (lsDEBUG, OfferCreateTransactor) << boost::str (boost::format ("takeOffers: done: dir=%d uTakeQuality=%d %c uTipQuality=%d saTakerRate=%s %c saTipRate=%s bPassive=%d")
                    % !!sleOfferDir
                    % uTakeQuality
//.........这里部分代码省略.........