Function DisconnectTip

src/main.cpp:1344–1389

Disconnect chainActive's tip.

// Disconnect chainActive's tip.
bool DisconnectTip(CValidationState &state) {
    auto bmTx = MAKE_BENCHMARK("DisconnectTip");
    CBlockIndex *pBlockIndexToDelete = chainActive.Tip();
    assert(pBlockIndexToDelete);
    // Read block from disk.
    CBlock block;
    if (!ReadBlockFromDisk(pBlockIndexToDelete, block))
        return state.Abort(_("Failed to read blocks from disk."));
    // Apply the block atomically to the chain state.
    auto spCW = std::make_shared<CCacheWrapper>(pCdMan);

    if (!DisconnectBlock(block, *spCW, pBlockIndexToDelete, state))
        return ERRORMSG("DisconnectBlock %s failed", pBlockIndexToDelete->GetBlockHash().ToString());

    // Need to re-sync all to global cache layer.
    spCW->Flush();

    // Attention: need to reset the lastest block price median
    CBlockIndex *pPreBlockIndex = pBlockIndexToDelete->pprev;
    CBlock preBlock;
    if (pPreBlockIndex) {
        if (!ReadBlockFromDisk(pPreBlockIndex, preBlock))
            return ERRORMSG("failed to read block [%d]: %s", pPreBlockIndex->height,
                            pPreBlockIndex->GetBlockHash().ToString());
    }

    // Write the chain state to disk, if necessary.
    if (!WriteChainState(state))
        return false;
    // Update chainActive and related variables.
    UpdateTip(pBlockIndexToDelete->pprev, block);
    // Resurrect mempool transactions from the disconnected block.
    for (const auto &pTx : block.vptx) {
        list<std::shared_ptr<CBaseTx> > removed;
        CValidationState stateDummy;
        if (!pTx->IsRelayForbidden()) {
            if (!AcceptToMemoryPool(mempool, stateDummy, pTx.get(), false)) {
                mempool.Remove(pTx.get(), removed, true);
            }
        } else {
            EraseTransactionFromWallet(pTx->GetHash());
        }
    }

    return true;
}

// Connect a new block to chainActive.
bool static ConnectTip(CValidationState &state, CBlockIndex *pIndexNew) {