Method AcceptBlock

src/validation.cpp:4308–4413

Store block on disk. If dbp is non-nullptr, the file is known to already reside on disk */

/** Store block on disk. If dbp is non-nullptr, the file is known to already reside on disk */
bool ChainstateManager::AcceptBlock(const std::shared_ptr<const CBlock>& pblock, BlockValidationState& state, CBlockIndex** ppindex, bool fRequested, const FlatFilePos* dbp, bool* fNewBlock, bool min_pow_checked)
{
    const CBlock& block = *pblock;

    if (fNewBlock) *fNewBlock = false;
    AssertLockHeld(cs_main);

    CBlockIndex *pindexDummy = nullptr;
    CBlockIndex *&pindex = ppindex ? *ppindex : pindexDummy;

    bool accepted_header{AcceptBlockHeader(block, state, &pindex, min_pow_checked)};
    CheckBlockIndex();

    if (!accepted_header)
        return false;

    // Check all requested blocks that we do not already have for validity and
    // save them to disk. Skip processing of unrequested blocks as an anti-DoS
    // measure, unless the blocks have more work than the active chain tip, and
    // aren't too far ahead of it, so are likely to be attached soon.
    bool fAlreadyHave = pindex->nStatus & BLOCK_HAVE_DATA;
    bool fHasMoreOrSameWork = (ActiveTip() ? pindex->nChainWork >= ActiveTip()->nChainWork : true);
    // Blocks that are too out-of-order needlessly limit the effectiveness of
    // pruning, because pruning will not delete block files that contain any
    // blocks which are too close in height to the tip.  Apply this test
    // regardless of whether pruning is enabled; it should generally be safe to
    // not process unrequested blocks.
    bool fTooFarAhead{pindex->nHeight > ActiveHeight() + int(MIN_BLOCKS_TO_KEEP)};

    // TODO: Decouple this function from the block download logic by removing fRequested
    // This requires some new chain data structure to efficiently look up if a
    // block is in a chain leading to a candidate for best tip, despite not
    // being such a candidate itself.
    // Note that this would break the getblockfrompeer RPC

    // TODO: deal better with return value and error conditions for duplicate
    // and unrequested blocks.
    if (fAlreadyHave) return true;
    if (!fRequested) {  // If we didn't ask for it:
        if (pindex->nTx != 0) return true;    // This is a previously-processed block that was pruned
        if (!fHasMoreOrSameWork) return true; // Don't process less-work chains
        if (fTooFarAhead) return true;        // Block height is too high

        // Protect against DoS attacks from low-work chains.
        // If our tip is behind, a peer could try to send us
        // low-work blocks on a fake chain that we would never
        // request; don't process these.
        if (pindex->nChainWork < MinimumChainWork()) return true;
    }

    const CChainParams& params{GetParams()};

    if (!CheckBlock(block, state, params.GetConsensus()) ||
        !ContextualCheckBlock(block, state, *this, pindex->pprev)) {
        if (Assume(state.IsInvalid())) {
            ActiveChainstate().InvalidBlockFound(pindex, state);
        }
        LogError("%s: %s\n", __func__, state.ToString());