rippled/include/xrpl/protocol/Asset.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2024 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_PROTOCOL_ASSET_H_INCLUDED
#define RIPPLE_PROTOCOL_ASSET_H_INCLUDED

#include <xrpl/basics/Number.h>
#include <xrpl/basics/base_uint.h>
#include <xrpl/protocol/Issue.h>
#include <xrpl/protocol/MPTIssue.h>

namespace ripple {

class Asset;
class STAmount;

template <typename TIss>
concept ValidIssueType =
    std::is_same_v<TIss, Issue> || std::is_same_v<TIss, MPTIssue>;

template <typename A>
concept AssetType =
    std::is_convertible_v<A, Asset> || std::is_convertible_v<A, Issue> ||
    std::is_convertible_v<A, MPTIssue> || std::is_convertible_v<A, MPTID>;

/* Asset is an abstraction of three different issue types: XRP, IOU, MPT.
 * For historical reasons, two issue types XRP and IOU are wrapped in Issue
 * type. Many functions and classes there were first written for Issue
 * have been rewritten for Asset.
 */
class Asset
{
public:
    using value_type = std::variant<Issue, MPTIssue>;

private:
    value_type issue_;

public:
    Asset() = default;

    /** Conversions to Asset are implicit and conversions to specific issue
     *  type are explicit. This design facilitates the use of Asset.
     */
    Asset(Issue const& issue) : issue_(issue)
    {
    }

    Asset(MPTIssue const& mptIssue) : issue_(mptIssue)
    {
    }

    Asset(MPTID const& issuanceID) : issue_(MPTIssue{issuanceID})
    {
    }

    AccountID const&
    getIssuer() const;

    template <ValidIssueType TIss>
    constexpr TIss const&
    get() const;

    template <ValidIssueType TIss>
    TIss&
    get();

    template <ValidIssueType TIss>
    constexpr bool
    holds() const;

    std::string
    getText() const;

    constexpr value_type const&
    value() const;

    void
    setJson(Json::Value& jv) const;

    STAmount
    operator()(Number const&) const;

    bool
    native() const
    {
        return holds<Issue>() && get<Issue>().native();
    }

    friend constexpr bool
    operator==(Asset const& lhs, Asset const& rhs);

    friend constexpr std::weak_ordering
    operator<=>(Asset const& lhs, Asset const& rhs);

    friend constexpr bool
    operator==(Currency const& lhs, Asset const& rhs);

    /** Return true if both assets refer to the same currency (regardless of
     * issuer) or MPT issuance. Otherwise return false.
     */
    friend constexpr bool
    equalTokens(Asset const& lhs, Asset const& rhs);
};

inline Json::Value
to_json(Asset const& asset)
{
    Json::Value jv;
    asset.setJson(jv);
    return jv;
}

template <ValidIssueType TIss>
constexpr bool
Asset::holds() const
{
    return std::holds_alternative<TIss>(issue_);
}

template <ValidIssueType TIss>
constexpr TIss const&
Asset::get() const
{
    if (!std::holds_alternative<TIss>(issue_))
        Throw<std::logic_error>("Asset is not a requested issue");
    return std::get<TIss>(issue_);
}

template <ValidIssueType TIss>
TIss&
Asset::get()
{
    if (!std::holds_alternative<TIss>(issue_))
        Throw<std::logic_error>("Asset is not a requested issue");
    return std::get<TIss>(issue_);
}

constexpr Asset::value_type const&
Asset::value() const
{
    return issue_;
}

constexpr bool
operator==(Asset const& lhs, Asset const& rhs)
{
    return std::visit(
        [&]<typename TLhs, typename TRhs>(
            TLhs const& issLhs, TRhs const& issRhs) {
            if constexpr (std::is_same_v<TLhs, TRhs>)
                return issLhs == issRhs;
            else
                return false;
        },
        lhs.issue_,
        rhs.issue_);
}

constexpr std::weak_ordering
operator<=>(Asset const& lhs, Asset const& rhs)
{
    return std::visit(
        []<ValidIssueType TLhs, ValidIssueType TRhs>(
            TLhs const& lhs_, TRhs const& rhs_) {
            if constexpr (std::is_same_v<TLhs, TRhs>)
                return std::weak_ordering(lhs_ <=> rhs_);
            else if constexpr (
                std::is_same_v<TLhs, Issue> && std::is_same_v<TRhs, MPTIssue>)
                return std::weak_ordering::greater;
            else
                return std::weak_ordering::less;
        },
        lhs.issue_,
        rhs.issue_);
}

constexpr bool
operator==(Currency const& lhs, Asset const& rhs)
{
    return rhs.holds<Issue>() && rhs.get<Issue>().currency == lhs;
}

constexpr bool
equalTokens(Asset const& lhs, Asset const& rhs)
{
    return std::visit(
        [&]<typename TLhs, typename TRhs>(
            TLhs const& issLhs, TRhs const& issRhs) {
            if constexpr (
                std::is_same_v<TLhs, Issue> && std::is_same_v<TRhs, Issue>)
                return issLhs.currency == issRhs.currency;
            else if constexpr (
                std::is_same_v<TLhs, MPTIssue> &&
                std::is_same_v<TRhs, MPTIssue>)
                return issLhs.getMptID() == issRhs.getMptID();
            else
                return false;
        },
        lhs.issue_,
        rhs.issue_);
}

inline bool
isXRP(Asset const& asset)
{
    return asset.native();
}

std::string
to_string(Asset const& asset);

bool
validJSONAsset(Json::Value const& jv);

Asset
assetFromJson(Json::Value const& jv);

}  // namespace ripple

#endif  // RIPPLE_PROTOCOL_ASSET_H_INCLUDED