EscrowFinish.cpp

#include <xrpl/tx/transactors/escrow/EscrowFinish.h>
 
#include <xrpl/basics/Log.h>
#include <xrpl/basics/Slice.h>
#include <xrpl/basics/chrono.h>
#include <xrpl/conditions/Condition.h>
#include <xrpl/conditions/Fulfillment.h>
#include <xrpl/core/HashRouter.h>
#include <xrpl/ledger/ApplyView.h>
#include <xrpl/ledger/ReadView.h>
#include <xrpl/ledger/View.h>
#include <xrpl/ledger/helpers/AccountRootHelpers.h>
#include <xrpl/ledger/helpers/CredentialHelpers.h>
#include <xrpl/ledger/helpers/EscrowHelpers.h>
#include <xrpl/ledger/helpers/MPTokenHelpers.h>
#include <xrpl/ledger/helpers/RippleStateHelpers.h>
#include <xrpl/ledger/helpers/TokenHelpers.h>
#include <xrpl/protocol/AccountID.h>
#include <xrpl/protocol/Concepts.h>
#include <xrpl/protocol/Feature.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/Issue.h>
#include <xrpl/protocol/MPTIssue.h>
#include <xrpl/protocol/Rate.h>
#include <xrpl/protocol/SField.h>
#include <xrpl/protocol/STAmount.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <xrpl/protocol/STTx.h>
#include <xrpl/protocol/SeqProxy.h>
#include <xrpl/protocol/TER.h>
#include <xrpl/protocol/XRPAmount.h>
#include <xrpl/tx/Transactor.h>
 
#include <system_error>
#include <variant>
 
namespace xrpl {
 
// During an EscrowFinish, the transaction must specify both
// a condition and a fulfillment. We track whether that
// fulfillment matches and validates the condition.
constexpr HashRouterFlags kSfCfInvalid = HashRouterFlags::PRIVATE5;
constexpr HashRouterFlags kSfCfValid = HashRouterFlags::PRIVATE6;
 
//------------------------------------------------------------------------------
 
static bool
checkCondition(Slice f, Slice c)
{
    using namespace xrpl::cryptoconditions;
 
    std::error_code ec;
 
    auto condition = Condition::deserialize(c, ec);
    if (!condition)
        return false;
 
    auto fulfillment = Fulfillment::deserialize(f, ec);
    if (!fulfillment)
        return false;
 
    return validate(*fulfillment, *condition);
}
 
bool
EscrowFinish::checkExtraFeatures(PreflightContext const& ctx)
{
    return !ctx.tx.isFieldPresent(sfCredentialIDs) || ctx.rules.enabled(featureCredentials);
}
 
NotTEC
EscrowFinish::preflight(PreflightContext const& ctx)
{
    auto const cb = ctx.tx[~sfCondition];
    auto const fb = ctx.tx[~sfFulfillment];
 
    // If you specify a condition, then you must also specify
    // a fulfillment.
    if (static_cast<bool>(cb) != static_cast<bool>(fb))
        return temMALFORMED;
 
    return tesSUCCESS;
}
 
NotTEC
EscrowFinish::preflightSigValidated(PreflightContext const& ctx)
{
    auto const cb = ctx.tx[~sfCondition];
    auto const fb = ctx.tx[~sfFulfillment];
 
    if (cb && fb)
    {
        auto& router = ctx.registry.get().getHashRouter();
 
        auto const id = ctx.tx.getTransactionID();
        auto const flags = router.getFlags(id);
 
        // If we haven't checked the condition, check it
        // now. Whether it passes or not isn't important
        // in preflight.
        if (!any(flags & (kSfCfInvalid | kSfCfValid)))
        {
            if (checkCondition(*fb, *cb))
            {
                router.setFlags(id, kSfCfValid);
            }
            else
            {
                router.setFlags(id, kSfCfInvalid);
            }
        }
    }
 
    if (auto const err = credentials::checkFields(ctx.tx, ctx.rules, ctx.j); !isTesSuccess(err))
        return err;
 
    return tesSUCCESS;
}
 
XRPAmount
EscrowFinish::calculateBaseFee(ReadView const& view, STTx const& tx)
{
    XRPAmount extraFee{0};
 
    if (auto const fb = tx[~sfFulfillment])
    {
        extraFee += view.fees().base * (32 + (fb->size() / 16));
    }
 
    return Transactor::calculateBaseFee(view, tx) + extraFee;
}
 
template <ValidIssueType T>
static TER
escrowFinishPreclaimHelper(
    PreclaimContext const& ctx,
    AccountID const& dest,
    STAmount const& amount);
 
template <>
TER
escrowFinishPreclaimHelper<Issue>(
    PreclaimContext const& ctx,
    AccountID const& dest,
    STAmount const& amount)
{
    AccountID const& issuer = amount.getIssuer();
    // If the issuer is the same as the account, return tesSUCCESS
    if (issuer == dest)
        return tesSUCCESS;
 
    // If the issuer has requireAuth set, check if the destination is authorized
    if (auto const ter = requireAuth(ctx.view, amount.get<Issue>(), dest); !isTesSuccess(ter))
        return ter;
 
    // If the issuer has deep frozen the destination, return tecFROZEN
    if (isDeepFrozen(ctx.view, dest, amount.get<Issue>().currency, amount.getIssuer()))
        return tecFROZEN;
 
    return tesSUCCESS;
}
 
template <>
TER
escrowFinishPreclaimHelper<MPTIssue>(
    PreclaimContext const& ctx,
    AccountID const& dest,
    STAmount const& amount)
{
    AccountID const& issuer = amount.getIssuer();
    // If the issuer is the same as the dest, return tesSUCCESS
    if (issuer == dest)
        return tesSUCCESS;
 
    // If the mpt does not exist, return tecOBJECT_NOT_FOUND
    auto const issuanceKey = keylet::mptokenIssuance(amount.get<MPTIssue>().getMptID());
    auto const sleIssuance = ctx.view.read(issuanceKey);
    if (!sleIssuance)
        return tecOBJECT_NOT_FOUND;
 
    // If the issuer has requireAuth set, check if the destination is
    // authorized
    auto const& mptIssue = amount.get<MPTIssue>();
    if (auto const ter = requireAuth(ctx.view, mptIssue, dest, AuthType::WeakAuth);
        !isTesSuccess(ter))
        return ter;
 
    // If the issuer has frozen the destination, return tecLOCKED
    if (isFrozen(ctx.view, dest, mptIssue))
        return tecLOCKED;
 
    return tesSUCCESS;
}
 
TER
EscrowFinish::preclaim(PreclaimContext const& ctx)
{
    if (ctx.view.rules().enabled(featureCredentials))
    {
        if (auto const err = credentials::valid(ctx.tx, ctx.view, ctx.tx[sfAccount], ctx.j);
            !isTesSuccess(err))
            return err;
    }
 
    if (ctx.view.rules().enabled(featureTokenEscrow))
    {
        auto const seqProxy = SeqProxy::rawSequence(ctx.tx[sfOfferSequence]);
        auto const k = keylet::escrow(ctx.tx[sfOwner], seqProxy);
        auto const slep = ctx.view.read(k);
        if (!slep)
            return tecNO_TARGET;
 
        AccountID const dest = (*slep)[sfDestination];
        STAmount const amount = (*slep)[sfAmount];
 
        if (!isXRP(amount))
        {
            if (auto const ret = std::visit(
                    [&]<typename T>(T const&) {
                        return escrowFinishPreclaimHelper<T>(ctx, dest, amount);
                    },
                    amount.asset().value());
                !isTesSuccess(ret))
                return ret;
        }
    }
    return tesSUCCESS;
}
 
TER
EscrowFinish::doApply()
{
    auto const seqProxy = SeqProxy::rawSequence(ctx_.tx[sfOfferSequence]);
    auto const k = keylet::escrow(ctx_.tx[sfOwner], seqProxy);
    auto const slep = ctx_.view().peek(k);
    if (!slep)
    {
        if (ctx_.view().rules().enabled(featureTokenEscrow))
            return tecINTERNAL;  // LCOV_EXCL_LINE
 
        return tecNO_TARGET;
    }
 
    // If a cancel time is present, a finish operation should only succeed prior
    // to that time.
    auto const now = ctx_.view().header().parentCloseTime;
 
    // Too soon: can't execute before the finish time
    if ((*slep)[~sfFinishAfter] && !after(now, (*slep)[sfFinishAfter]))
        return tecNO_PERMISSION;
 
    // Too late: can't execute after the cancel time
    if ((*slep)[~sfCancelAfter] && after(now, (*slep)[sfCancelAfter]))
        return tecNO_PERMISSION;
 
    // Check cryptocondition fulfillment
    {
        auto const id = ctx_.tx.getTransactionID();
        auto flags = ctx_.registry.get().getHashRouter().getFlags(id);
 
        auto const cb = ctx_.tx[~sfCondition];
 
        // It's unlikely that the results of the check will
        // expire from the hash router, but if it happens,
        // simply re-run the check.
        if (cb && !any(flags & (kSfCfInvalid | kSfCfValid)))
        {
            // LCOV_EXCL_START
            auto const fb = ctx_.tx[~sfFulfillment];
 
            if (!fb)
                return tecINTERNAL;
 
            if (checkCondition(*fb, *cb))
            {
                flags = kSfCfValid;
            }
            else
            {
                flags = kSfCfInvalid;
            }
 
            ctx_.registry.get().getHashRouter().setFlags(id, flags);
            // LCOV_EXCL_STOP
        }
 
        // If the check failed, then simply return an error
        // and don't look at anything else.
        if (any(flags & kSfCfInvalid))
            return tecCRYPTOCONDITION_ERROR;
 
        // Check against condition in the ledger entry:
        auto const cond = (*slep)[~sfCondition];
 
        // If a condition wasn't specified during creation,
        // one shouldn't be included now.
        if (!cond && cb)
            return tecCRYPTOCONDITION_ERROR;
 
        // If a condition was specified during creation of
        // the suspended payment, the identical condition
        // must be presented again. We don't check if the
        // fulfillment matches the condition since we did
        // that in preflight.
        if (cond && (cond != cb))
            return tecCRYPTOCONDITION_ERROR;
    }
 
    // NOTE: Escrow payments cannot be used to fund accounts.
    AccountID const destID = (*slep)[sfDestination];
    auto const sled = ctx_.view().peek(keylet::account(destID));
    if (!sled)
        return tecNO_DST;
 
    if (auto err =
            verifyDepositPreauth(ctx_.tx, ctx_.view(), accountID_, destID, sled, ctx_.journal);
        !isTesSuccess(err))
        return err;
 
    AccountID const account = (*slep)[sfAccount];
 
    // Remove escrow from owner directory
    {
        auto const page = (*slep)[sfOwnerNode];
        if (!ctx_.view().dirRemove(keylet::ownerDir(account), page, k.key, true))
        {
            // LCOV_EXCL_START
            JLOG(j_.fatal()) << "Unable to delete Escrow from owner.";
            return tefBAD_LEDGER;
            // LCOV_EXCL_STOP
        }
    }
 
    // Remove escrow from recipient's owner directory, if present.
    if (auto const optPage = (*slep)[~sfDestinationNode])
    {
        if (!ctx_.view().dirRemove(keylet::ownerDir(destID), *optPage, k.key, true))
        {
            // LCOV_EXCL_START
            JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
            return tefBAD_LEDGER;
            // LCOV_EXCL_STOP
        }
    }
 
    // With the Sponsor amendment, release the escrow reserve before delivery.
    // Token delivery can auto-create a destination holding, and the same
    // sponsor (or the same account, for a self-escrow) may cover both the
    // escrow being removed and the holding being created. Without the
    // amendment, keep the legacy order: releasing early changes the reserve
    // arithmetic for self-escrows and would break consensus if not gated.
    bool const sponsorEnabled = ctx_.view().rules().enabled(featureSponsor);
    if (sponsorEnabled)
        decreaseOwnerCountForObject(ctx_.view(), account, slep, 1, ctx_.journal);
 
    STAmount const amount = slep->getFieldAmount(sfAmount);
    // Transfer amount to destination
    if (isXRP(amount))
    {
        (*sled)[sfBalance] = (*sled)[sfBalance] + amount;
    }
    else
    {
        if (!ctx_.view().rules().enabled(featureTokenEscrow))
            return temDISABLED;  // LCOV_EXCL_LINE
 
        Rate lockedRate = slep->isFieldPresent(sfTransferRate)
            ? xrpl::Rate(slep->getFieldU32(sfTransferRate))
            : kParityRate;
        auto const issuer = amount.getIssuer();
        bool const createAsset = destID == accountID_;
        if (auto const ret = std::visit(
                [&]<typename T>(T const&) {
                    return escrowUnlockApplyHelper<T>(
                        ctx_.getApplyViewContext(),
                        lockedRate,
                        sled,
                        preFeeBalance_,
                        amount,
                        issuer,
                        account,
                        destID,
                        createAsset,
                        j_);
                },
                amount.asset().value());
            !isTesSuccess(ret))
            return ret;
 
        // Remove escrow from issuers owner directory, if present.
        if (auto const optPage = (*slep)[~sfIssuerNode]; optPage)
        {
            if (!ctx_.view().dirRemove(keylet::ownerDir(issuer), *optPage, k.key, true))
            {
                // LCOV_EXCL_START
                JLOG(j_.fatal()) << "Unable to delete Escrow from recipient.";
                return tefBAD_LEDGER;
                // LCOV_EXCL_STOP
            }
        }
    }
 
    ctx_.view().update(sled);
 
    // Adjust source owner count (legacy position, pre-Sponsor)
    if (!sponsorEnabled)
        decreaseOwnerCountForObject(ctx_.view(), account, slep, 1, ctx_.journal);
 
    // Remove escrow from ledger
    ctx_.view().erase(slep);
    return tesSUCCESS;
}
 
void
EscrowFinish::visitInvariantEntry(bool, SLE::const_ref, SLE::const_ref)
{
    // No transaction-specific invariants yet (future work).
}
 
bool
EscrowFinish::finalizeInvariants(
    STTx const&,
    TER,
    XRPAmount,
    ReadView const&,
    beast::Journal const&)
{
    // No transaction-specific invariants yet (future work).
    return true;
}
}  // namespace xrpl