Files
rippled/src/libxrpl/tx/paths/AMMOffer.cpp
2026-04-01 15:46:14 +00:00

142 lines
4.9 KiB
C++

#include <xrpl/protocol/QualityFunction.h>
#include <xrpl/tx/paths/AMMLiquidity.h>
#include <xrpl/tx/paths/AMMOffer.h>
namespace xrpl {
template <typename TIn, typename TOut>
AMMOffer<TIn, TOut>::AMMOffer(
AMMLiquidity<TIn, TOut> const& ammLiquidity,
TAmounts<TIn, TOut> const& amounts,
TAmounts<TIn, TOut> const& balances,
Quality const& quality)
: ammLiquidity_(ammLiquidity), amounts_(amounts), balances_(balances), quality_(quality)
{
}
template <typename TIn, typename TOut>
Issue const&
AMMOffer<TIn, TOut>::issueIn() const
{
return ammLiquidity_.issueIn();
}
template <typename TIn, typename TOut>
AccountID const&
AMMOffer<TIn, TOut>::owner() const
{
return ammLiquidity_.ammAccount();
}
template <typename TIn, typename TOut>
TAmounts<TIn, TOut> const&
AMMOffer<TIn, TOut>::amount() const
{
return amounts_;
}
template <typename TIn, typename TOut>
void
AMMOffer<TIn, TOut>::consume(ApplyView& view, TAmounts<TIn, TOut> const& consumed)
{
// Consumed offer must be less or equal to the original
if (consumed.in > amounts_.in || consumed.out > amounts_.out)
Throw<std::logic_error>("Invalid consumed AMM offer.");
// AMM pool is updated when the amounts are transferred
// in BookStep::consumeOffer().
consumed_ = true;
// Let the context know AMM offer is consumed
ammLiquidity_.context().setAMMUsed();
}
template <typename TIn, typename TOut>
TAmounts<TIn, TOut>
AMMOffer<TIn, TOut>::limitOut(
TAmounts<TIn, TOut> const& offerAmount,
TOut const& limit,
bool roundUp) const
{
// Change the offer size proportionally to the original offer quality
// to keep the strands quality order unchanged. The taker pays slightly
// more for the offer in this case, which results in a slightly higher
// pool product than the original pool product. I.e. if the original
// pool is poolPays, poolGets and the offer is assetIn, assetOut then
// poolPays * poolGets < (poolPays - assetOut) * (poolGets + assetIn)
if (ammLiquidity_.multiPath())
{
// It turns out that the ceil_out implementation has some slop in
// it, which ceil_out_strict removes.
return quality().ceil_out_strict(offerAmount, limit, roundUp);
}
// Change the offer size according to the conservation function. The offer
// quality is increased in this case, but it doesn't matter since there is
// only one path.
return {swapAssetOut(balances_, limit, ammLiquidity_.tradingFee()), limit};
}
template <typename TIn, typename TOut>
TAmounts<TIn, TOut>
AMMOffer<TIn, TOut>::limitIn(TAmounts<TIn, TOut> const& offerAmount, TIn const& limit, bool roundUp)
const
{
// See the comments above in limitOut().
if (ammLiquidity_.multiPath())
{
if (auto const& rules = getCurrentTransactionRules();
rules && rules->enabled(fixReducedOffersV2))
return quality().ceil_in_strict(offerAmount, limit, roundUp);
return quality().ceil_in(offerAmount, limit);
}
return {limit, swapAssetIn(balances_, limit, ammLiquidity_.tradingFee())};
}
template <typename TIn, typename TOut>
QualityFunction
AMMOffer<TIn, TOut>::getQualityFunc() const
{
if (ammLiquidity_.multiPath())
return QualityFunction{quality(), QualityFunction::CLOBLikeTag{}};
return QualityFunction{balances_, ammLiquidity_.tradingFee(), QualityFunction::AMMTag{}};
}
template <typename TIn, typename TOut>
bool
AMMOffer<TIn, TOut>::checkInvariant(TAmounts<TIn, TOut> const& consumed, beast::Journal j) const
{
if (consumed.in > amounts_.in || consumed.out > amounts_.out)
{
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;
}
Number const product = balances_.in * balances_.out;
auto const newBalances =
TAmounts<TIn, TOut>{balances_.in + consumed.in, balances_.out - consumed.out};
Number const newProduct = newBalances.in * newBalances.out;
if (newProduct >= product || withinRelativeDistance(product, newProduct, Number{1, -7}))
return true;
JLOG(j.error()) << "AMMOffer::checkInvariant failed: balances " << to_string(balances_.in)
<< " " << to_string(balances_.out) << " new balances "
<< to_string(newBalances.in) << " " << to_string(newBalances.out)
<< " product/newProduct " << product << " " << newProduct << " diff "
<< (product != Number{0} ? to_string((product - newProduct) / product)
: "undefined");
return false;
}
template class AMMOffer<STAmount, STAmount>;
template class AMMOffer<IOUAmount, IOUAmount>;
template class AMMOffer<XRPAmount, IOUAmount>;
template class AMMOffer<IOUAmount, XRPAmount>;
} // namespace xrpl