Offer.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2014 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_APP_BOOK_OFFER_H_INCLUDED
#define RIPPLE_APP_BOOK_OFFER_H_INCLUDED
 
#include <xrpld/ledger/View.h>
#include <xrpl/basics/contract.h>
#include <xrpl/protocol/Quality.h>
#include <xrpl/protocol/Rules.h>
#include <xrpl/protocol/SField.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <ostream>
#include <stdexcept>
 
namespace ripple {
 
template <class TIn, class TOut>
class TOfferBase
{
protected:
    Issue issIn_;
    Issue issOut_;
};
 
template <>
class TOfferBase<STAmount, STAmount>
{
public:
    explicit TOfferBase() = default;
};
 
template <class TIn = STAmount, class TOut = STAmount>
class TOffer : private TOfferBase<TIn, TOut>
{
private:
    SLE::pointer m_entry;
    Quality m_quality;
    AccountID m_account;
 
    TAmounts<TIn, TOut> m_amounts;
    void
    setFieldAmounts();
 
public:
    TOffer() = default;
 
    TOffer(SLE::pointer const& entry, Quality quality);
 
    Quality
    quality() const noexcept
    {
        return m_quality;
    }
 
    AccountID const&
    owner() const
    {
        return m_account;
    }
 
    TAmounts<TIn, TOut> const&
    amount() const
    {
        return m_amounts;
    }
 
    bool
    fully_consumed() const
    {
        if (m_amounts.in <= beast::zero)
            return true;
        if (m_amounts.out <= beast::zero)
            return true;
        return false;
    }
 
    void
    consume(ApplyView& view, TAmounts<TIn, TOut> const& consumed)
    {
        if (consumed.in > m_amounts.in)
            Throw<std::logic_error>("can't consume more than is available.");
 
        if (consumed.out > m_amounts.out)
            Throw<std::logic_error>("can't produce more than is available.");
 
        m_amounts -= consumed;
        setFieldAmounts();
        view.update(m_entry);
    }
 
    std::string
    id() const
    {
        return to_string(m_entry->key());
    }
 
    std::optional<uint256>
    key() const
    {
        return m_entry->key();
    }
 
    Issue const&
    issueIn() const;
    Issue const&
    issueOut() const;
 
    TAmounts<TIn, TOut>
    limitOut(
        TAmounts<TIn, TOut> const& offrAmt,
        TOut const& limit,
        bool roundUp) const;
 
    TAmounts<TIn, TOut>
    limitIn(TAmounts<TIn, TOut> const& offrAmt, TIn const& limit, bool roundUp)
        const;
 
    template <typename... Args>
    static TER
    send(Args&&... args);
 
    bool
    isFunded() const
    {
        // Offer owner is issuer; they have unlimited funds
        return m_account == issueOut().account;
    }
 
    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};
    }
 
    bool
    checkInvariant(TAmounts<TIn, TOut> const&, beast::Journal j) const
    {
        return true;
    }
};
 
using Offer = TOffer<>;
 
template <class TIn, class TOut>
TOffer<TIn, TOut>::TOffer(SLE::pointer const& entry, Quality quality)
    : m_entry(entry)
    , m_quality(quality)
    , m_account(m_entry->getAccountID(sfAccount))
{
    auto const tp = m_entry->getFieldAmount(sfTakerPays);
    auto const tg = m_entry->getFieldAmount(sfTakerGets);
    m_amounts.in = toAmount<TIn>(tp);
    m_amounts.out = toAmount<TOut>(tg);
    this->issIn_ = tp.issue();
    this->issOut_ = tg.issue();
}
 
template <>
inline TOffer<STAmount, STAmount>::TOffer(
    SLE::pointer const& entry,
    Quality quality)
    : m_entry(entry)
    , m_quality(quality)
    , m_account(m_entry->getAccountID(sfAccount))
    , m_amounts(
          m_entry->getFieldAmount(sfTakerPays),
          m_entry->getFieldAmount(sfTakerGets))
{
}
 
template <class TIn, class TOut>
void
TOffer<TIn, TOut>::setFieldAmounts()
{
#ifdef _MSC_VER
    UNREACHABLE("ripple::TOffer::setFieldAmounts : must be specialized");
#else
    static_assert(sizeof(TOut) == -1, "Must be specialized");
#endif
}
 
template <class TIn, class TOut>
TAmounts<TIn, TOut>
TOffer<TIn, TOut>::limitOut(
    TAmounts<TIn, TOut> const& offrAmt,
    TOut const& limit,
    bool roundUp) const
{
    if (auto const& rules = getCurrentTransactionRules();
        rules && rules->enabled(fixReducedOffersV1))
        // It turns out that the ceil_out implementation has some slop in
        // it.  ceil_out_strict removes that slop.  But removing that slop
        // affects transaction outcomes, so the change must be made using
        // an amendment.
        return quality().ceil_out_strict(offrAmt, limit, roundUp);
    return m_quality.ceil_out(offrAmt, limit);
}
 
template <class TIn, class TOut>
TAmounts<TIn, TOut>
TOffer<TIn, TOut>::limitIn(
    TAmounts<TIn, TOut> const& offrAmt,
    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().ceil_in_strict(offrAmt, limit, roundUp);
    return m_quality.ceil_in(offrAmt, limit);
}
 
template <class TIn, class TOut>
template <typename... Args>
TER
TOffer<TIn, TOut>::send(Args&&... args)
{
    return accountSend(std::forward<Args>(args)...);
}
 
template <>
inline void
TOffer<STAmount, STAmount>::setFieldAmounts()
{
    m_entry->setFieldAmount(sfTakerPays, m_amounts.in);
    m_entry->setFieldAmount(sfTakerGets, m_amounts.out);
}
 
template <>
inline void
TOffer<IOUAmount, IOUAmount>::setFieldAmounts()
{
    m_entry->setFieldAmount(sfTakerPays, toSTAmount(m_amounts.in, issIn_));
    m_entry->setFieldAmount(sfTakerGets, toSTAmount(m_amounts.out, issOut_));
}
 
template <>
inline void
TOffer<IOUAmount, XRPAmount>::setFieldAmounts()
{
    m_entry->setFieldAmount(sfTakerPays, toSTAmount(m_amounts.in, issIn_));
    m_entry->setFieldAmount(sfTakerGets, toSTAmount(m_amounts.out));
}
 
template <>
inline void
TOffer<XRPAmount, IOUAmount>::setFieldAmounts()
{
    m_entry->setFieldAmount(sfTakerPays, toSTAmount(m_amounts.in));
    m_entry->setFieldAmount(sfTakerGets, toSTAmount(m_amounts.out, issOut_));
}
 
template <class TIn, class TOut>
Issue const&
TOffer<TIn, TOut>::issueIn() const
{
    return this->issIn_;
}
 
template <>
inline Issue const&
TOffer<STAmount, STAmount>::issueIn() const
{
    return m_amounts.in.issue();
}
 
template <class TIn, class TOut>
Issue const&
TOffer<TIn, TOut>::issueOut() const
{
    return this->issOut_;
}
 
template <>
inline Issue const&
TOffer<STAmount, STAmount>::issueOut() const
{
    return m_amounts.out.issue();
}
 
template <class TIn, class TOut>
inline std::ostream&
operator<<(std::ostream& os, TOffer<TIn, TOut> const& offer)
{
    return os << offer.id();
}
 
}  // namespace ripple
 
#endif