Method ActivateBestChain

src/validation.cpp:3333–3498

}

bool Chainstate::ActivateBestChain(BlockValidationState& state, std::shared_ptr<const CBlock> pblock)
{
    AssertLockNotHeld(m_chainstate_mutex);

    // Note that while we're often called here from ProcessNewBlock, this is
    // far from a guarantee. Things in the P2P/RPC will often end up calling
    // us in the middle of ProcessNewBlock - do not assume pblock is set
    // sanely for performance or correctness!
    AssertLockNotHeld(::cs_main);

    // ABC maintains a fair degree of expensive-to-calculate internal state
    // because this function periodically releases cs_main so that it does not lock up other threads for too long
    // during large connects - and to allow for e.g. the callback queue to drain
    // we use m_chainstate_mutex to enforce mutual exclusion so that only one caller may execute this function at a time
    LOCK(m_chainstate_mutex);

    // Belt-and-suspenders check that we aren't attempting to advance the
    // chainstate past the target block.
    if (WITH_LOCK(::cs_main, return m_target_utxohash)) {
        LogError("%s", STR_INTERNAL_BUG("m_target_utxohash is set - this chainstate should not be in operation."));
        return Assume(false);
    }

    CBlockIndex *pindexMostWork = nullptr;
    CBlockIndex *pindexNewTip = nullptr;
    bool exited_ibd{false};
    do {
        // Block until the validation queue drains. This should largely
        // never happen in normal operation, however may happen during
        // reindex, causing memory blowup if we run too far ahead.
        // Note that if a validationinterface callback ends up calling
        // ActivateBestChain this may lead to a deadlock! We should
        // probably have a DEBUG_LOCKORDER test for this in the future.
        if (m_chainman.m_options.signals) LimitValidationInterfaceQueue(*m_chainman.m_options.signals);

        {
            LOCK(cs_main);
            {
            // Lock transaction pool for at least as long as it takes for connected_blocks to be consumed
            LOCK(MempoolMutex());
            const bool was_in_ibd = m_chainman.IsInitialBlockDownload();
            CBlockIndex* starting_tip = m_chain.Tip();
            bool blocks_connected = false;
            do {
                // We absolutely may not unlock cs_main until we've made forward progress
                // (with the exception of shutdown due to hardware issues, low disk space, etc).
                std::vector<ConnectedBlock> connected_blocks; // Destructed before cs_main is unlocked

                if (pindexMostWork == nullptr) {
                    pindexMostWork = FindMostWorkChain();
                }

                // Whether we have anything to do at all.
                if (pindexMostWork == nullptr || pindexMostWork == m_chain.Tip()) {
                    break;
                }

                bool fInvalidFound = false;