src/test/jtx/amount.h

#pragma once
 
#include <test/jtx/Account.h>
#include <test/jtx/tags.h>
 
#include <xrpl/basics/contract.h>
#include <xrpl/protocol/Issue.h>
#include <xrpl/protocol/STAmount.h>
#include <xrpl/protocol/Units.h>
 
#include <cstdint>
#include <ostream>
#include <string>
#include <type_traits>
 
namespace xrpl {
namespace detail {
 
struct epsilon_multiple
{
    std::size_t n;
};
 
}  // namespace detail
 
namespace test {
namespace jtx {
 
/*
 
The decision was made to accept amounts of drops and XRP
using an int type, since the range of XRP is 100 billion
and having both signed and unsigned overloads creates
tricky code leading to overload resolution ambiguities.
 
*/
 
struct AnyAmount;
 
// Represents "no amount" of a currency
// This is distinct from zero or a balance.
// For example, no USD means the trust line
// doesn't even exist. Using this in an
// inappropriate context will generate a
// compile error.
//
struct None
{
    Asset asset;
};
 
//------------------------------------------------------------------------------
 
// This value is also defined in SystemParameters.h. It's
// duplicated here to catch any possible future errors that
// could change that value (however unlikely).
constexpr XRPAmount dropsPerXRP{1'000'000};
 
struct PrettyAmount
{
private:
    // VFALCO TODO should be Amount
    STAmount amount_;
    std::string name_;
 
public:
    PrettyAmount() = default;
    PrettyAmount(PrettyAmount const&) = default;
    PrettyAmount&
    operator=(PrettyAmount const&) = default;
 
    PrettyAmount(STAmount const& amount, std::string const& name) : amount_(amount), name_(name)
    {
    }
 
    template <class T>
    PrettyAmount(
        T v,
        std::enable_if_t<
            sizeof(T) >= sizeof(int) && std::is_integral_v<T> && std::is_signed_v<T>>* = nullptr)
        : amount_((v > 0) ? v : -v, v < 0)
    {
    }
 
    template <class T>
    PrettyAmount(
        T v,
        std::enable_if_t<sizeof(T) >= sizeof(int) && std::is_unsigned_v<T>>* = nullptr)
        : amount_(v)
    {
    }
 
    PrettyAmount(XRPAmount v) : amount_(v)
    {
    }
 
    std::string const&
    name() const
    {
        return name_;
    }
 
    STAmount const&
    value() const
    {
        return amount_;
    }
 
    Number
    number() const
    {
        return amount_;
    }
 
    inline int
    signum() const
    {
        return amount_.signum();
    }
 
    operator STAmount const&() const
    {
        return amount_;
    }
 
    operator AnyAmount() const;
 
    operator Json::Value() const
    {
        return to_json(value());
    }
};
 
inline bool
operator==(PrettyAmount const& lhs, PrettyAmount const& rhs)
{
    return lhs.value() == rhs.value();
}
 
inline bool
operator!=(PrettyAmount const& lhs, PrettyAmount const& rhs)
{
    return !operator==(lhs, rhs);
}
 
std::ostream&
operator<<(std::ostream& os, PrettyAmount const& amount);
 
struct PrettyAsset
{
private:
    Asset asset_;
    std::uint32_t scale_;
 
public:
    template <typename A>
        requires std::convertible_to<A, Asset>
    PrettyAsset(A const& asset, std::uint32_t scale = 1) : PrettyAsset{Asset{asset}, scale}
    {
    }
 
    PrettyAsset(Asset const& asset, std::uint32_t scale = 1) : asset_(asset), scale_(scale)
    {
    }
 
    Asset const&
    raw() const
    {
        return asset_;
    }
 
    operator Asset const&() const
    {
        return asset_;
    }
 
    operator Json::Value() const
    {
        return to_json(asset_);
    }
 
    template <std::integral T>
    PrettyAmount
    operator()(T v, Number::rounding_mode rounding = Number::getround()) const
    {
        return operator()(Number(v), rounding);
    }
 
    PrettyAmount
    operator()(Number v, Number::rounding_mode rounding = Number::getround()) const
    {
        NumberRoundModeGuard const mg(rounding);
        STAmount const amount{asset_, v * scale_};
        return {amount, ""};
    }
 
    None
    operator()(none_t) const
    {
        return {asset_};
    }
 
    bool
    integral() const
    {
        return asset_.integral();
    }
 
    bool
    native() const
    {
        return asset_.native();
    }
 
    template <ValidIssueType TIss>
    bool
    holds() const
    {
        return asset_.holds<TIss>();
    }
};
//------------------------------------------------------------------------------
 
// Specifies an order book
struct BookSpec
{
    AccountID account;
    xrpl::Currency currency;
 
    BookSpec(AccountID const& account_, xrpl::Currency const& currency_)
        : account(account_), currency(currency_)
    {
    }
};
 
//------------------------------------------------------------------------------
 
struct XRP_t
{
    operator Issue() const
    {
        return xrpIssue();
    }
 
    bool
    integral() const
    {
        return true;
    }
 
    template <class T, class = std::enable_if_t<std::is_integral_v<T>>>
    PrettyAmount
    operator()(T v) const
    {
        using TOut = std::conditional_t<std::is_signed_v<T>, std::int64_t, std::uint64_t>;
        return {TOut{v} * dropsPerXRP};
    }
 
    PrettyAmount
    operator()(Number v) const
    {
        auto const c = dropsPerXRP.drops();
        auto const d = std::int64_t(v * c);
        if (Number(d) / c != v)
            Throw<std::domain_error>("unrepresentable");
        return {d};
    }
 
    PrettyAmount
    operator()(double v) const
    {
        auto const c = dropsPerXRP.drops();
        if (v >= 0)
        {
            auto const d = std::uint64_t(std::round(v * c));
            if (double(d) / c != v)
                Throw<std::domain_error>("unrepresentable");
            return {d};
        }
        auto const d = std::int64_t(std::round(v * c));
        if (double(d) / c != v)
            Throw<std::domain_error>("unrepresentable");
        return {d};
    }
    None
    operator()(none_t) const
    {
        return {xrpIssue()};
    }
 
    friend BookSpec
    operator~(XRP_t const&)
    {
        return BookSpec(xrpAccount(), xrpCurrency());
    }
};
 
extern XRP_t const XRP;
 
template <class Integer, class = std::enable_if_t<std::is_integral_v<Integer>>>
PrettyAmount
drops(Integer i)
{
    return {i};
}
 
inline PrettyAmount
drops(XRPAmount i)
{
    return {i};
}
 
//------------------------------------------------------------------------------
 
// The smallest possible IOU STAmount
struct epsilon_t
{
    epsilon_t()
    {
    }
 
    detail::epsilon_multiple
    operator()(std::size_t n) const
    {
        return {n};
    }
};
 
static epsilon_t const epsilon;
 
class IOU
{
public:
    Account account;
    xrpl::Currency currency;
 
    IOU(Account const& account_, xrpl::Currency const& currency_)
        : account(account_), currency(currency_)
    {
    }
 
    Issue
    issue() const
    {
        return {currency, account.id()};
    }
    Asset
    asset() const
    {
        return issue();
    }
    bool
    integral() const
    {
        return issue().integral();
    }
 
    operator Issue() const
    {
        return issue();
    }
    operator PrettyAsset() const
    {
        return asset();
    }
 
    template <
        class T,
        class = std::enable_if_t<sizeof(T) >= sizeof(int) && std::is_arithmetic<T>::value>>
    PrettyAmount
    operator()(T v) const
    {
        // VFALCO NOTE Should throw if the
        //             representation of v is not exact.
        return {amountFromString(issue(), std::to_string(v)), account.name()};
    }
 
    PrettyAmount
    operator()(epsilon_t) const;
    PrettyAmount
    operator()(detail::epsilon_multiple) const;
 
    // VFALCO TODO
    // STAmount operator()(char const* s) const;
 
    None
    operator()(none_t) const
    {
        return {issue()};
    }
 
    friend BookSpec
    operator~(IOU const& iou)
    {
        return BookSpec(iou.account.id(), iou.currency);
    }
};
 
std::ostream&
operator<<(std::ostream& os, IOU const& iou);
 
//------------------------------------------------------------------------------
 
class MPT
{
public:
    std::string name;
    xrpl::MPTID issuanceID;
 
    MPT(std::string const& n, xrpl::MPTID const& issuanceID_) : name(n), issuanceID(issuanceID_)
    {
    }
 
    xrpl::MPTID const&
    mpt() const
    {
        return issuanceID;
    }
 
    xrpl::MPTIssue
    mptIssue() const
    {
        return MPTIssue{issuanceID};
    }
    Asset
    asset() const
    {
        return mptIssue();
    }
    bool
    integral() const
    {
        return true;
    }
 
    operator xrpl::MPTIssue() const
    {
        return mptIssue();
    }
 
    operator PrettyAsset() const
    {
        return asset();
    }
 
    template <class T>
        requires(sizeof(T) >= sizeof(int) && std::is_arithmetic_v<T>)
    PrettyAmount
    operator()(T v) const
    {
        return {amountFromString(mpt(), std::to_string(v)), name};
    }
 
    PrettyAmount
    operator()(epsilon_t) const;
    PrettyAmount
    operator()(detail::epsilon_multiple) const;
 
    None
    operator()(none_t) const
    {
        return {mptIssue()};
    }
 
    friend BookSpec
    operator~(MPT const& mpt)
    {
        assert(false);
        Throw<std::logic_error>("MPT is not supported");
        return BookSpec{beast::zero, noCurrency()};
    }
};
 
std::ostream&
operator<<(std::ostream& os, MPT const& mpt);
 
//------------------------------------------------------------------------------
 
struct any_t
{
    inline AnyAmount
    operator()(STAmount const& sta) const;
};
 
struct AnyAmount
{
    bool is_any;
    STAmount value;
 
    AnyAmount() = delete;
    AnyAmount(AnyAmount const&) = default;
    AnyAmount&
    operator=(AnyAmount const&) = default;
 
    AnyAmount(STAmount const& amount) : is_any(false), value(amount)
    {
    }
 
    AnyAmount(STAmount const& amount, any_t const*) : is_any(true), value(amount)
    {
    }
 
    // Reset the issue to a specific account
    void
    to(AccountID const& id)
    {
        if (!is_any)
            return;
        value.setIssuer(id);
    }
};
 
inline AnyAmount
any_t::operator()(STAmount const& sta) const
{
    return AnyAmount(sta, this);
}
 
extern any_t const any;
 
}  // namespace jtx
}  // namespace test
}  // namespace xrpl