Function IsTopoSortedPackage

src/policy/packages.cpp:19–41

IsTopoSortedPackage where a set of txids has been pre-populated. The set is assumed to be correct and * is mutated within this function (even if return value is false). */

/** IsTopoSortedPackage where a set of txids has been pre-populated. The set is assumed to be correct and
 * is mutated within this function (even if return value is false). */
bool IsTopoSortedPackage(const Package& txns, std::unordered_set<Txid, SaltedTxidHasher>& later_txids)
{
    // Avoid misusing this function: later_txids should contain the txids of txns.
    Assume(txns.size() == later_txids.size());

    // later_txids always contains the txids of this transaction and the ones that come later in
    // txns. If any transaction's input spends a tx in that set, we've found a parent placed later
    // than its child.
    for (const auto& tx : txns) {
        for (const auto& input : tx->vin) {
            if (later_txids.contains(input.prevout.hash)) {
                // The parent is a subsequent transaction in the package.
                return false;
            }
        }
        // Avoid misusing this function: later_txids must contain every tx.
        Assume(later_txids.erase(tx->GetHash()) == 1);
    }

    // Avoid misusing this function: later_txids should have contained the txids of txns.
    Assume(later_txids.empty());
    return true;
}

bool IsTopoSortedPackage(const Package& txns)
{