rippled/src/libxrpl/ledger/helpers/VaultHelpers.cpp

#include <xrpl/ledger/helpers/VaultHelpers.h>

#include <xrpl/basics/Number.h>
#include <xrpl/beast/utility/instrumentation.h>
#include <xrpl/ledger/ReadView.h>
#include <xrpl/protocol/AccountID.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/LedgerFormats.h>
#include <xrpl/protocol/SField.h>
#include <xrpl/protocol/STAmount.h>
#include <xrpl/protocol/STLedgerEntry.h>
#include <xrpl/protocol/STNumber.h>  // IWYU pragma: keep

#include <cstdint>
#include <memory>
#include <optional>

namespace xrpl {

[[nodiscard]] std::optional<STAmount>
assetsToSharesDeposit(
    std::shared_ptr<SLE const> const& vault,
    std::shared_ptr<SLE const> const& issuance,
    STAmount const& assets)
{
    XRPL_ASSERT(!assets.negative(), "xrpl::assetsToSharesDeposit : non-negative assets");
    XRPL_ASSERT(
        assets.asset() == vault->at(sfAsset),
        "xrpl::assetsToSharesDeposit : assets and vault match");
    if (assets.negative() || assets.asset() != vault->at(sfAsset))
        return std::nullopt;  // LCOV_EXCL_LINE

    Number const assetTotal = vault->at(sfAssetsTotal);
    STAmount shares{vault->at(sfShareMPTID)};
    if (assetTotal == 0)
    {
        return STAmount{
            shares.asset(),
            Number(assets.mantissa(), assets.exponent() + vault->at(sfScale)).truncate()};
    }

    Number const shareTotal = issuance->at(sfOutstandingAmount);
    shares = ((shareTotal * assets) / assetTotal).truncate();
    return shares;
}

[[nodiscard]] std::optional<STAmount>
sharesToAssetsDeposit(
    std::shared_ptr<SLE const> const& vault,
    std::shared_ptr<SLE const> const& issuance,
    STAmount const& shares)
{
    XRPL_ASSERT(!shares.negative(), "xrpl::sharesToAssetsDeposit : non-negative shares");
    XRPL_ASSERT(
        shares.asset() == vault->at(sfShareMPTID),
        "xrpl::sharesToAssetsDeposit : shares and vault match");
    if (shares.negative() || shares.asset() != vault->at(sfShareMPTID))
        return std::nullopt;  // LCOV_EXCL_LINE

    Number const assetTotal = vault->at(sfAssetsTotal);
    STAmount assets{vault->at(sfAsset)};
    if (assetTotal == 0)
    {
        return STAmount{
            assets.asset(), shares.mantissa(), shares.exponent() - vault->at(sfScale), false};
    }

    Number const shareTotal = issuance->at(sfOutstandingAmount);
    assets = (assetTotal * shares) / shareTotal;
    return assets;
}

[[nodiscard]] std::optional<STAmount>
assetsToSharesWithdraw(
    std::shared_ptr<SLE const> const& vault,
    std::shared_ptr<SLE const> const& issuance,
    STAmount const& assets,
    TruncateShares truncate,
    WaiveUnrealizedLoss waive)
{
    XRPL_ASSERT(!assets.negative(), "xrpl::assetsToSharesWithdraw : non-negative assets");
    XRPL_ASSERT(
        assets.asset() == vault->at(sfAsset),
        "xrpl::assetsToSharesWithdraw : assets and vault match");
    if (assets.negative() || assets.asset() != vault->at(sfAsset))
        return std::nullopt;  // LCOV_EXCL_LINE

    Number assetTotal = vault->at(sfAssetsTotal);
    if (waive == WaiveUnrealizedLoss::No)
        assetTotal -= vault->at(sfLossUnrealized);
    STAmount shares{vault->at(sfShareMPTID)};
    if (assetTotal == 0)
        return shares;
    Number const shareTotal = issuance->at(sfOutstandingAmount);
    Number result = (shareTotal * assets) / assetTotal;
    if (truncate == TruncateShares::Yes)
        result = result.truncate();
    shares = result;
    return shares;
}

[[nodiscard]] std::optional<STAmount>
sharesToAssetsWithdraw(
    std::shared_ptr<SLE const> const& vault,
    std::shared_ptr<SLE const> const& issuance,
    STAmount const& shares,
    WaiveUnrealizedLoss waive)
{
    XRPL_ASSERT(!shares.negative(), "xrpl::sharesToAssetsWithdraw : non-negative shares");
    XRPL_ASSERT(
        shares.asset() == vault->at(sfShareMPTID),
        "xrpl::sharesToAssetsWithdraw : shares and vault match");
    if (shares.negative() || shares.asset() != vault->at(sfShareMPTID))
        return std::nullopt;  // LCOV_EXCL_LINE

    Number assetTotal = vault->at(sfAssetsTotal);
    if (waive == WaiveUnrealizedLoss::No)
        assetTotal -= vault->at(sfLossUnrealized);
    STAmount assets{vault->at(sfAsset)};
    if (assetTotal == 0)
        return assets;
    Number const shareTotal = issuance->at(sfOutstandingAmount);
    assets = (assetTotal * shares) / shareTotal;
    return assets;
}

[[nodiscard]] bool
isSoleShareholder(ReadView const& view, AccountID const& account, SLE::const_ref issuance)
{
    XRPL_ASSERT(
        issuance && issuance->getType() == ltMPTOKEN_ISSUANCE,
        "xrpl::isSoleShareholder : valid issuance SLE");

    std::uint64_t const outstanding = issuance->at(sfOutstandingAmount);
    if (outstanding == 0)
        return false;

    auto const shareMPTID =
        makeMptID(issuance->getFieldU32(sfSequence), issuance->getAccountID(sfIssuer));
    auto const sleToken = view.read(keylet::mptoken(shareMPTID, account));
    if (!sleToken)
        return false;  // LCOV_EXCL_LINE

    return sleToken->getFieldU64(sfMPTAmount) == outstanding;
}

}  // namespace xrpl