Method WriteUndoDataForBlock

src/node/blockstorage.cpp:725–753

}

bool BlockManager::WriteUndoDataForBlock(const CBlockUndo& blockundo, BlockValidationState& state, CBlockIndex* pindex, const CChainParams& chainparams)
{
    AssertLockHeld(::cs_main);
    // Write undo information to disk
    if (pindex->GetUndoPos().IsNull()) {
        FlatFilePos _pos;
        if (!FindUndoPos(state, pindex->nFile, _pos, ::GetSerializeSize(blockundo, CLIENT_VERSION) + 40)) {
            return error("ConnectBlock(): FindUndoPos failed");
        }
        if (!UndoWriteToDisk(blockundo, _pos, pindex->pprev->GetBlockHash(), chainparams.MessageStart())) {
            return AbortNode(state, "Failed to write undo data");
        }
        // rev files are written in block height order, whereas blk files are written as blocks come in (often out of order)
        // we want to flush the rev (undo) file once we've written the last block, which is indicated by the last height
        // in the block file info as below; note that this does not catch the case where the undo writes are keeping up
        // with the block writes (usually when a synced up node is getting newly mined blocks) -- this case is caught in
        // the FindBlockPos function
        if (_pos.nFile < m_last_blockfile && static_cast<uint32_t>(pindex->nHeight) == m_blockfile_info[_pos.nFile].nHeightLast) {
            FlushUndoFile(_pos.nFile, true);
        }

        // update nUndoPos in block index
        pindex->nUndoPos = _pos.nPos;
        pindex->nStatus |= BLOCK_HAVE_UNDO;
        m_dirty_blockindex.insert(pindex);
    }

    return true;
}

bool ReadBlockFromDisk(CBlock& block, const FlatFilePos& pos, const Consensus::Params& consensusParams)
{