Method UpdateTransactionsFromBlock

src/txmempool.cpp:109–150

vHashesToUpdate is the set of transaction hashes from a disconnected block which has been re-added to the mempool. for each entry, look for descendants that are outside vHashesToUpdate, and add fee/size information for such descendants to the parent. for each such descendant, also update the ancestor state to include the parent.

// add fee/size information for such descendants to the parent.
// for each such descendant, also update the ancestor state to include the parent.
void CTxMemPool::UpdateTransactionsFromBlock(const std::vector<uint256> &vHashesToUpdate)
{
    LOCK(cs);
    // For each entry in vHashesToUpdate, store the set of in-mempool, but not
    // in-vHashesToUpdate transactions, so that we don't have to recalculate
    // descendants when we come across a previously seen entry.
    cacheMap mapMemPoolDescendantsToUpdate;

    // Use a set for lookups into vHashesToUpdate (these entries are already
    // accounted for in the state of their ancestors)
    std::set<uint256> setAlreadyIncluded(vHashesToUpdate.begin(), vHashesToUpdate.end());

    // Iterate in reverse, so that whenever we are looking at a transaction
    // we are sure that all in-mempool descendants have already been processed.
    // This maximizes the benefit of the descendant cache and guarantees that
    // setMemPoolChildren will be updated, an assumption made in
    // UpdateForDescendants.
    for (const uint256 &hash : reverse_iterate(vHashesToUpdate)) {
        // we cache the in-mempool children to avoid duplicate updates
        setEntries setChildren;
        // calculate children from mapNextTx
        txiter it = mapTx.find(hash);
        if (it == mapTx.end()) {
            continue;
        }
        auto iter = mapNextTx.lower_bound(COutPoint(hash, 0));
        // First calculate the children, and update setMemPoolChildren to
        // include them, and update their setMemPoolParents to include this tx.
        for (; iter != mapNextTx.end() && iter->first->hash == hash; ++iter) {
            const uint256 &childHash = iter->second->GetHash();
            txiter childIter = mapTx.find(childHash);
            assert(childIter != mapTx.end());
            // We can skip updating entries we've encountered before or that
            // are in the block (which are already accounted for).
            if (setChildren.insert(childIter).second && !setAlreadyIncluded.count(childHash)) {
                UpdateChild(it, childIter, true);
                UpdateParent(childIter, it, true);
            }
        }
        UpdateForDescendants(it, mapMemPoolDescendantsToUpdate, setAlreadyIncluded);
    }
}

bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntries &setAncestors, uint64_t limitAncestorCount, uint64_t limitAncestorSize, uint64_t limitDescendantCount, uint64_t limitDescendantSize, std::string &errString, bool fSearchForParents /* = true */) const
{