AccountChannels.cpp

#include <xrpld/rpc/Context.h>
#include <xrpld/rpc/detail/RPCHelpers.h>
#include <xrpld/rpc/detail/RPCLedgerHelpers.h>
#include <xrpld/rpc/detail/Tuning.h>
 
#include <xrpl/basics/StringUtilities.h>
#include <xrpl/basics/base_uint.h>
#include <xrpl/basics/strHex.h>
#include <xrpl/beast/utility/Zero.h>
#include <xrpl/beast/utility/instrumentation.h>
#include <xrpl/core/ServiceRegistry.h>
#include <xrpl/json/json_value.h>
#include <xrpl/ledger/ReadView.h>
#include <xrpl/ledger/helpers/DirectoryHelpers.h>
#include <xrpl/protocol/AccountID.h>
#include <xrpl/protocol/ErrorCodes.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/LedgerFormats.h>
#include <xrpl/protocol/PublicKey.h>
#include <xrpl/protocol/RPCErr.h>
#include <xrpl/protocol/SField.h>
#include <xrpl/protocol/jss.h>
#include <xrpl/protocol/tokens.h>
#include <xrpl/resource/Fees.h>
 
#include <cstdint>
#include <memory>
#include <optional>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
 
namespace xrpl {
 
void
addChannel(json::Value& jsonLines, SLE const& line)
{
    json::Value& jDst(jsonLines.append(json::ValueType::Object));
    jDst[jss::channel_id] = to_string(line.key());
    jDst[jss::account] = to_string(line[sfAccount]);
    jDst[jss::destination_account] = to_string(line[sfDestination]);
    jDst[jss::amount] = line[sfAmount].getText();
    jDst[jss::balance] = line[sfBalance].getText();
    if (publicKeyType(line[sfPublicKey]))
    {
        PublicKey const pk(line[sfPublicKey]);
        jDst[jss::public_key] = toBase58(TokenType::AccountPublic, pk);
        jDst[jss::public_key_hex] = strHex(pk);
    }
    jDst[jss::settle_delay] = line[sfSettleDelay];
    if (auto const& v = line[~sfExpiration])
        jDst[jss::expiration] = *v;
    if (auto const& v = line[~sfCancelAfter])
        jDst[jss::cancel_after] = *v;
    if (auto const& v = line[~sfSourceTag])
        jDst[jss::source_tag] = *v;
    if (auto const& v = line[~sfDestinationTag])
        jDst[jss::destination_tag] = *v;
}
 
// {
//   account: <account>
//   ledger_hash : <ledger>
//   ledger_index : <ledger_index>
//   limit: integer                 // optional
//   marker: opaque                 // optional, resume previous query
// }
json::Value
doAccountChannels(rpc::JsonContext& context)
{
    auto const& params(context.params);
    if (!params.isMember(jss::account))
        return rpc::missingFieldError(jss::account);
 
    if (!params[jss::account].isString())
        return rpc::invalidFieldError(jss::account);
 
    std::shared_ptr<ReadView const> ledger;
    auto result = rpc::lookupLedger(ledger, context);
    if (!ledger)
        return result;
 
    auto id = parseBase58<AccountID>(params[jss::account].asString());
    if (!id)
    {
        return rpcError(RpcActMalformed);
    }
    AccountID const accountID{id.value()};
 
    if (!ledger->exists(keylet::account(accountID)))
        return rpcError(RpcActNotFound);
 
    std::string strDst;
    if (params.isMember(jss::destination_account))
    {
        if (!params[jss::destination_account].isString())
            return rpc::invalidFieldError(jss::destination_account);
        strDst = params[jss::destination_account].asString();
    }
 
    auto const raDstAccount = [&]() -> std::optional<AccountID> {
        return strDst.empty() ? std::nullopt : parseBase58<AccountID>(strDst);
    }();
    if (!strDst.empty() && !raDstAccount)
        return rpcError(RpcActMalformed);
 
    unsigned int limit = 0;
    if (auto err = readLimitField(limit, rpc::tuning::kAccountChannels, context))
        return *err;
 
    json::Value jsonChannels{json::ValueType::Array};
    struct VisitData
    {
        std::vector<SLE::const_pointer> items;
        AccountID const& accountID;
        std::optional<AccountID> const& raDstAccount;
    };
    VisitData visitData = {.items = {}, .accountID = accountID, .raDstAccount = raDstAccount};
    visitData.items.reserve(limit);
    uint256 startAfter = beast::kZero;
    std::uint64_t startHint = 0;
 
    if (params.isMember(jss::marker))
    {
        if (!params[jss::marker].isString())
            return rpc::expectedFieldError(jss::marker, "string");
 
        // Marker is composed of a comma separated index and start hint. The
        // former will be read as hex, and the latter as a decimal integer.
        std::stringstream marker(params[jss::marker].asString());
        std::string value;
        if (!std::getline(marker, value, ','))
            return rpcError(RpcInvalidParams);
 
        if (!startAfter.parseHex(value))
            return rpcError(RpcInvalidParams);
 
        if (!std::getline(marker, value, ','))
            return rpcError(RpcInvalidParams);
 
        auto const hint = toUInt64(value);
        if (!hint.has_value())
            return rpcError(RpcInvalidParams);
        startHint = *hint;
 
        // We then must check if the object pointed to by the marker is actually
        // owned by the account in the request.
        auto const sle = ledger->read({ltANY, startAfter});
 
        if (!sle)
            return rpcError(RpcInvalidParams);
 
        if (!rpc::isRelatedToAccount(*ledger, sle, accountID))
            return rpcError(RpcInvalidParams);
    }
 
    auto count = 0;
    std::optional<uint256> marker = {};
    std::uint64_t nextHint = 0;
    if (!forEachItemAfter(
            *ledger,
            accountID,
            startAfter,
            startHint,
            limit + 1,
            [&visitData, &accountID, &count, &limit, &marker, &nextHint](SLE::const_ref sleCur) {
                if (!sleCur)
                {
                    // LCOV_EXCL_START
                    UNREACHABLE("xrpl::doAccountChannels : null SLE");
                    return false;
                    // LCOV_EXCL_STOP
                }
 
                if (++count == limit)
                {
                    marker = sleCur->key();
                    nextHint = rpc::getStartHint(sleCur, visitData.accountID);
                }
 
                if (count <= limit && sleCur->getType() == ltPAYCHAN &&
                    (*sleCur)[sfAccount] == accountID &&
                    (!visitData.raDstAccount ||
                     *visitData.raDstAccount == (*sleCur)[sfDestination]))
                {
                    visitData.items.emplace_back(sleCur);
                }
 
                return true;
            }))
    {
        return rpcError(RpcInvalidParams);
    }
 
    // Both conditions need to be checked because marker is set on the limit-th
    // item, but if there is no item on the limit + 1 iteration, then there is
    // no need to return a marker.
    if (count == limit + 1 && marker)
    {
        result[jss::limit] = limit;
        result[jss::marker] = to_string(*marker) + "," + std::to_string(nextHint);
    }
 
    result[jss::account] = toBase58(accountID);
 
    for (auto const& item : visitData.items)
        addChannel(jsonChannels, *item);
 
    context.loadType = resource::kFeeMediumBurdenRpc;
    result[jss::channels] = std::move(jsonChannels);
    return result;
}
 
}  // namespace xrpl