tx/paths/Offer.h

#pragma once
 
#include <xrpl/basics/Log.h>
#include <xrpl/basics/base_uint.h>
#include <xrpl/basics/contract.h>
#include <xrpl/beast/utility/Journal.h>
#include <xrpl/beast/utility/Zero.h>
#include <xrpl/ledger/ApplyView.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/Quality.h>
#include <xrpl/protocol/Rules.h>
#include <xrpl/protocol/SField.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <xrpl/protocol/TER.h>
 
#include <cstdint>
#include <optional>
#include <ostream>
#include <stdexcept>
#include <string>
#include <utility>
 
namespace xrpl {
 
template <StepAmount TIn, StepAmount TOut>
class TOffer
{
private:
    SLE::pointer entry_;
    Quality quality_{};
    AccountID accountID_;
    Asset assetIn_;
    Asset assetOut_;
 
    TAmounts<TIn, TOut> amounts_{};
    void
    setFieldAmounts();
 
public:
    TOffer() = default;
 
    TOffer(SLE::pointer entry, Quality quality);

    [[nodiscard]] Quality
    quality() const noexcept
    {
        return quality_;
    }

    [[nodiscard]] AccountID const&
    owner() const
    {
        return accountID_;
    }

    [[nodiscard]] TAmounts<TIn, TOut> const&
    amount() const
    {
        return amounts_;
    }

    [[nodiscard]] bool
    fullyConsumed() const
    {
        if (amounts_.in <= beast::kZero)
            return true;
        if (amounts_.out <= beast::kZero)
            return true;
        return false;
    }

    void
    consume(ApplyView& view, TAmounts<TIn, TOut> const& consumed)
    {
        if (consumed.in > amounts_.in)
            Throw<std::logic_error>("can't consume more than is available.");
 
        if (consumed.out > amounts_.out)
            Throw<std::logic_error>("can't produce more than is available.");
 
        amounts_ -= consumed;
        setFieldAmounts();
        view.update(entry_);
    }
 
    [[nodiscard]] std::string
    id() const
    {
        return to_string(entry_->key());
    }
 
    [[nodiscard]] std::optional<uint256>
    key() const
    {
        return entry_->key();
    }
 
    [[nodiscard]] Asset const&
    assetIn() const;
    [[nodiscard]] Asset const&
    assetOut() const;
 
    [[nodiscard]] TAmounts<TIn, TOut>
    limitOut(TAmounts<TIn, TOut> const& offerAmount, TOut const& limit, bool roundUp) const;
 
    [[nodiscard]] TAmounts<TIn, TOut>
    limitIn(TAmounts<TIn, TOut> const& offerAmount, TIn const& limit, bool roundUp) const;
 
    template <typename... Args>
    static TER
    send(Args&&... args);
 
    [[nodiscard]] bool
    isFunded() const
    {
        // Offer owner is issuer; they have unlimited funds if IOU
        return accountID_ == assetOut_.getIssuer() && assetOut_.holds<Issue>();
    }
 
    static std::pair<std::uint32_t, std::uint32_t>
    adjustRates(std::uint32_t ofrInRate, std::uint32_t ofrOutRate)
    {
        // CLOB offer pays the transfer fee
        return {ofrInRate, ofrOutRate};
    }

    [[nodiscard]] bool
    checkInvariant(TAmounts<TIn, TOut> const& consumed, beast::Journal j) const
    {
        if (!isFeatureEnabled(fixAMMv1_3))
            return true;
 
        if (consumed.in > amounts_.in || consumed.out > amounts_.out)
        {
            // LCOV_EXCL_START
            JLOG(j.error()) << "AMMOffer::checkInvariant failed: consumed "
                            << to_string(consumed.in) << " " << to_string(consumed.out)
                            << " amounts " << to_string(amounts_.in) << " "
                            << to_string(amounts_.out);
 
            return false;
            // LCOV_EXCL_STOP
        }
 
        return true;
    }
};
 
template <StepAmount TIn, StepAmount TOut>
TOffer<TIn, TOut>::TOffer(SLE::pointer entry, Quality quality)
    : entry_(std::move(entry)), quality_(quality), accountID_(entry_->getAccountID(sfAccount))
{
    auto const tp = entry_->getFieldAmount(sfTakerPays);
    auto const tg = entry_->getFieldAmount(sfTakerGets);
    amounts_.in = toAmount<TIn>(tp);
    amounts_.out = toAmount<TOut>(tg);
    assetIn_ = tp.asset();
    assetOut_ = tg.asset();
}
 
template <StepAmount TIn, StepAmount TOut>
void
TOffer<TIn, TOut>::setFieldAmounts()
{
    if constexpr (std::is_same_v<TIn, XRPAmount>)
    {
        entry_->setFieldAmount(sfTakerPays, toSTAmount(amounts_.in));
    }
    else
    {
        entry_->setFieldAmount(sfTakerPays, toSTAmount(amounts_.in, assetIn_));
    }
 
    if constexpr (std::is_same_v<TOut, XRPAmount>)
    {
        entry_->setFieldAmount(sfTakerGets, toSTAmount(amounts_.out));
    }
    else
    {
        entry_->setFieldAmount(sfTakerGets, toSTAmount(amounts_.out, assetOut_));
    }
}
 
template <StepAmount TIn, StepAmount TOut>
TAmounts<TIn, TOut>
TOffer<TIn, TOut>::limitOut(TAmounts<TIn, TOut> const& offerAmount, TOut const& limit, bool roundUp)
    const
{
    // It turns out that the ceil_out implementation has some slop in
    // it, which ceil_out_strict removes.
    return quality().ceilOutStrict(offerAmount, limit, roundUp);
}
 
template <StepAmount TIn, StepAmount TOut>
TAmounts<TIn, TOut>
TOffer<TIn, TOut>::limitIn(TAmounts<TIn, TOut> const& offerAmount, TIn const& limit, bool roundUp)
    const
{
    if (auto const& rules = getCurrentTransactionRules();
        rules && rules->enabled(fixReducedOffersV2))
    {
        // It turns out that the ceil_in implementation has some slop in
        // it.  ceil_in_strict removes that slop.  But removing that slop
        // affects transaction outcomes, so the change must be made using
        // an amendment.
        return quality().ceilInStrict(offerAmount, limit, roundUp);
    }
    return quality_.ceilIn(offerAmount, limit);
}
 
template <StepAmount TIn, StepAmount TOut>
template <typename... Args>
TER
TOffer<TIn, TOut>::send(Args&&... args)
{
    return accountSend(
        std::forward<Args>(args)..., SLE::pointer(), WaiveTransferFee::No, AllowMPTOverflow::Yes);
}
 
template <StepAmount TIn, StepAmount TOut>
Asset const&
TOffer<TIn, TOut>::assetIn() const
{
    return assetIn_;
}
 
template <StepAmount TIn, StepAmount TOut>
Asset const&
TOffer<TIn, TOut>::assetOut() const
{
    return assetOut_;
}
 
template <StepAmount TIn, StepAmount TOut>
inline std::ostream&
operator<<(std::ostream& os, TOffer<TIn, TOut> const& offer)
{
    return os << offer.id();
}
 
}  // namespace xrpl