Function LoadChainstate

src/node/chainstate.cpp:12–126

namespace node {
std::optional<ChainstateLoadingError> LoadChainstate(bool fReset,
                                                     ChainstateManager& chainman,
                                                     CTxMemPool* mempool,
                                                     bool fPruneMode,
                                                     const Consensus::Params& consensus_params,
                                                     bool fReindexChainState,
                                                     int64_t nBlockTreeDBCache,
                                                     int64_t nCoinDBCache,
                                                     int64_t nCoinCacheUsage,
                                                     bool block_tree_db_in_memory,
                                                     bool coins_db_in_memory,
                                                     std::function<bool()> shutdown_requested,
                                                     std::function<void()> coins_error_cb)
{
    auto is_coinsview_empty = [&](CChainState* chainstate) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
        return fReset || fReindexChainState || chainstate->CoinsTip().GetBestBlock().IsNull();
    };

    LOCK(cs_main);
    chainman.InitializeChainstate(mempool);
    chainman.m_total_coinstip_cache = nCoinCacheUsage;
    chainman.m_total_coinsdb_cache = nCoinDBCache;

    UnloadBlockIndex(mempool, chainman);

    auto& pblocktree{chainman.m_blockman.m_block_tree_db};
    // new CBlockTreeDB tries to delete the existing file, which
    // fails if it's still open from the previous loop. Close it first:
    pblocktree.reset();
    pblocktree.reset(new CBlockTreeDB(nBlockTreeDBCache, block_tree_db_in_memory, fReset));

    if (fReset) {
        pblocktree->WriteReindexing(true);
        //If we're reindexing in prune mode, wipe away unusable block files and all undo data files
        if (fPruneMode)
            CleanupBlockRevFiles();
    }

    if (shutdown_requested && shutdown_requested()) return ChainstateLoadingError::SHUTDOWN_PROBED;

    // LoadBlockIndex will load fHavePruned if we've ever removed a
    // block file from disk.
    // Note that it also sets fReindex based on the disk flag!
    // From here on out fReindex and fReset mean something different!
    if (!chainman.LoadBlockIndex()) {
        if (shutdown_requested && shutdown_requested()) return ChainstateLoadingError::SHUTDOWN_PROBED;
        return ChainstateLoadingError::ERROR_LOADING_BLOCK_DB;
    }

    if (!chainman.BlockIndex().empty() &&
            !chainman.m_blockman.LookupBlockIndex(consensus_params.hashGenesisBlock)) {
        return ChainstateLoadingError::ERROR_BAD_GENESIS_BLOCK;
    }

    // Check for changed -prune state.  What we are concerned about is a user who has pruned blocks
    // in the past, but is now trying to run unpruned.
    if (fHavePruned && !fPruneMode) {
        return ChainstateLoadingError::ERROR_PRUNED_NEEDS_REINDEX;