validation.cpp

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2017 The Bitcoin Core developers
// Copyright (c) 2020 The SmartUSD Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <validation.h>

#include <arith_uint256.h>
#include <auxpow.h>
#include <importcoin.h>
#include <chain.h>
#include <chainparams.h>
#include <checkpoints.h>
#include <checkqueue.h>
#include <consensus/consensus.h>
#include <consensus/merkle.h>
#include <consensus/tx_verify.h>
#include <consensus/validation.h>
#include <cuckoocache.h>
#include <hash.h>
#include <init.h>
#include <policy/fees.h>
#include <policy/policy.h>
#include <policy/rbf.h>
#include <pow.h>
#include <primitives/block.h>
#include <primitives/transaction.h>
#include <random.h>
#include <reverse_iterator.h>
#include <script/script.h>
#include <script/sigcache.h>
#include <script/standard.h>
#include <timedata.h>
#include <tinyformat.h>
#include <txdb.h>
#include <txmempool.h>
#include <ui_interface.h>
#include <undo.h>
#include <util.h>
#include <utilmoneystr.h>
#include <utilstrencodings.h>
#include <validationinterface.h>
#include <warnings.h>
#include <net.h>
#include <net_processing.h>
#include <komodo_validation016.h>

#include <future>
#include <sstream>

#include <boost/algorithm/string/replace.hpp>
#include <boost/algorithm/string/join.hpp>
#include <boost/thread.hpp>
#include <boost/foreach.hpp>

#if BOOST_VERSION >= 107300
#if !defined(BOOST_BIND_GLOBAL_PLACEHOLDERS)
using boost::placeholders::_1;
using boost::placeholders::_2;
#endif
#endif

#if defined(NDEBUG)
# error "Bitcoin cannot be compiled without assertions."
#endif

#define MICRO 0.000001
#define MILLI 0.001

#ifndef _BITS256
#define _BITS256
    union _bits256 { uint8_t bytes[32]; uint16_t ushorts[16]; uint32_t uints[8]; uint64_t ulongs[4]; uint64_t txid; };
    typedef union _bits256 bits256;
#endif

extern int32_t ASSETCHAINS_BLOCKTIME;
extern uint32_t ASSETCHAINS_CC;
extern pthread_mutex_t pricemutex;
extern void vcalc_sha256(char hashstr[(256 >> 3) * 2 + 1],uint8_t hash[256 >> 3],uint8_t *src,int32_t len);

#define PRICES_MAXDATAPOINTS 8
#define PRICES_DAYWINDOW ((3600*24/ASSETCHAINS_BLOCKTIME) + 1) // defined in komodo_defs.h
#define SMARTUSD_MAXPRICES 2048 // must be power of 2 and less than 8192
#define PRICES_ERRORRATE (COIN / 100)	  // maximum acceptable change, set at 1%
#define PRICES_SIZEBIT0 (sizeof(uint32_t) * 4) // 4 uint32_t unixtimestamp, BTCUSD, BTCGBP and BTCEUR

extern struct priceinfo
{
    FILE *fp;
    char symbol[64];
} PRICES[SMARTUSD_MAXPRICES];

/**
 * Global state
 */
namespace {
    struct CBlockIndexWorkComparator
    {
        bool operator()(const CBlockIndex *pa, const CBlockIndex *pb) const {
            // First sort by most total work, ...
            if (pa->nChainWork > pb->nChainWork) return false;
            if (pa->nChainWork < pb->nChainWork) return true;

            // ... then by earliest time received, ...
            if (pa->nSequenceId < pb->nSequenceId) return false;
            if (pa->nSequenceId > pb->nSequenceId) return true;

            // Use pointer address as tie breaker (should only happen with blocks
            // loaded from disk, as those all have id 0).
            if (pa < pb) return false;
            if (pa > pb) return true;

            // Identical blocks.
            return false;
        }
    };
} // anon namespace

class ConnectTrace;

/**
 * CChainState stores and provides an API to update our local knowledge of the
 * current best chain and header tree.
 *
 * It generally provides access to the current block tree, as well as functions
 * to provide new data, which it will appropriately validate and incorporate in
 * its state as necessary.
 *
 * Eventually, the API here is targeted at being exposed externally as a
 * consumable libconsensus library, so any functions added must only call
 * other class member functions, pure functions in other parts of the consensus
 * library, callbacks via the validation interface, or read/write-to-disk
 * functions (eventually this will also be via callbacks).
 */
class CChainState {
private:
    /**
     * The set of all CBlockIndex entries with BLOCK_VALID_TRANSACTIONS (for itself and all ancestors) and
     * as good as our current tip or better. Entries may be failed, though, and pruning nodes may be
     * missing the data for the block.
     */
    std::set<CBlockIndex*, CBlockIndexWorkComparator> setBlockIndexCandidates;

    /**
     * Every received block is assigned a unique and increasing identifier, so we
     * know which one to give priority in case of a fork.
     */
    CCriticalSection cs_nBlockSequenceId;
    /** Blocks loaded from disk are assigned id 0, so start the counter at 1. */
    int32_t nBlockSequenceId = 1;
    /** Decreasing counter (used by subsequent preciousblock calls). */
    int32_t nBlockReverseSequenceId = -1;
    /** chainwork for the last block that preciousblock has been applied to. */
    arith_uint256 nLastPreciousChainwork = 0;

    /** In order to efficiently track invalidity of headers, we keep the set of
      * blocks which we tried to connect and found to be invalid here (ie which
      * were set to BLOCK_FAILED_VALID since the last restart). We can then
      * walk this set and check if a new header is a descendant of something in
      * this set, preventing us from having to walk mapBlockIndex when we try
      * to connect a bad block and fail.
      *
      * While this is more complicated than marking everything which descends
      * from an invalid block as invalid at the time we discover it to be
      * invalid, doing so would require walking all of mapBlockIndex to find all
      * descendants. Since this case should be very rare, keeping track of all
      * BLOCK_FAILED_VALID blocks in a set should be just fine and work just as
      * well.
      *
      * Because we already walk mapBlockIndex in height-order at startup, we go
      * ahead and mark descendants of invalid blocks as FAILED_CHILD at that time,
      * instead of putting things in this set.
      */
    std::set<CBlockIndex*> g_failed_blocks;

    /**
     * the ChainState CriticalSection
     * A lock that must be held when modifying this ChainState - held in ActivateBestChain()
     */
    CCriticalSection m_cs_chainstate;

public:
    CChain chainActive;
    BlockMap mapBlockIndex;
    std::multimap<CBlockIndex*, CBlockIndex*> mapBlocksUnlinked;
    CBlockIndex *pindexBestInvalid = nullptr;

    bool LoadBlockIndex(const Consensus::Params& consensus_params, CBlockTreeDB& blocktree);

    bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock);

    bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex);
    bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const CDiskBlockPos* dbp, bool* fNewBlock);

    // Block (dis)connection on a given view:
    DisconnectResult DisconnectBlock(const CBlock& block, const CBlockIndex* pindex, CCoinsViewCache& view, bool fJustCheck = false);
    bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex,
                    CCoinsViewCache& view,
                    const CChainParams& chainparams, bool fJustCheck = false);

    // Block disconnection on our pcoinsTip:
    bool DisconnectTip(CValidationState& state, const CChainParams& chainparams, DisconnectedBlockTransactions *disconnectpool);

    // Manual block validity manipulation:
    bool PreciousBlock(CValidationState& state, const CChainParams& params, CBlockIndex *pindex);
    bool InvalidateBlock(CValidationState& state, const CChainParams& chainparams, CBlockIndex *pindex);
    bool ResetBlockFailureFlags(CBlockIndex *pindex);

    bool ReplayBlocks(const CChainParams& params, CCoinsView* view);
    bool RewindBlockIndex(const CChainParams& params);
    bool LoadGenesisBlock(const CChainParams& chainparams);

    void PruneBlockIndexCandidates();

    void UnloadBlockIndex();

private:
    bool ActivateBestChainStep(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace);
    bool ConnectTip(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexNew, const std::shared_ptr<const CBlock>& pblock, ConnectTrace& connectTrace, DisconnectedBlockTransactions &disconnectpool);

    CBlockIndex* AddToBlockIndex(const CBlockHeader& block);
    /** Create a new block index entry for a given block hash */
    CBlockIndex * InsertBlockIndex(const uint256& hash);
    void CheckBlockIndex(const Consensus::Params& consensusParams);

    void InvalidBlockFound(CBlockIndex *pindex, const CValidationState &state);
    CBlockIndex* FindMostWorkChain();
    bool ReceivedBlockTransactions(const CBlock &block, CValidationState& state, CBlockIndex *pindexNew, const CDiskBlockPos& pos, const Consensus::Params& consensusParams);


    bool RollforwardBlock(const CBlockIndex* pindex, CCoinsViewCache& inputs, const CChainParams& params);
} g_chainstate;



CCriticalSection cs_main;

BlockMap& mapBlockIndex = g_chainstate.mapBlockIndex;
CChain& chainActive = g_chainstate.chainActive;
CBlockIndex *pindexBestHeader = nullptr;
CWaitableCriticalSection csBestBlock;
CConditionVariable cvBlockChange;
uint256 hashBestBlock;
int nScriptCheckThreads = 0;
std::atomic_bool fImporting(false);
std::atomic_bool fReindex(false);
bool fTxIndex = false;
bool fAddressIndex = false;
bool fTimestampIndex = false;
bool fSpentIndex = false;
bool fHavePruned = false;
bool fPruneMode = false;
bool fIsBareMultisigStd = DEFAULT_PERMIT_BAREMULTISIG;
bool fRequireStandard = true;
bool fCheckBlockIndex = false;
bool fCheckpointsEnabled = DEFAULT_CHECKPOINTS_ENABLED;
size_t nCoinCacheUsage = 5000 * 300;
uint64_t nPruneTarget = 0;
int64_t nMaxTipAge = DEFAULT_MAX_TIP_AGE;
bool fEnableReplacement = DEFAULT_ENABLE_REPLACEMENT;

uint256 hashAssumeValid;
arith_uint256 nMinimumChainWork;

CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE);
CAmount maxTxFee = DEFAULT_TRANSACTION_MAXFEE;

CBlockPolicyEstimator feeEstimator;
CTxMemPool mempool(&feeEstimator);
//CTxMemPool tmpmempool(&feeEstimator); //

/** Constant stuff for coinbase transactions we create: */
CScript COINBASE_FLAGS;

const std::string strMessageMagic = "Bitcoin Signed Message:\n";

// Internal stuff
namespace {
    CBlockIndex *&pindexBestInvalid = g_chainstate.pindexBestInvalid;

    /** All pairs A->B, where A (or one of its ancestors) misses transactions, but B has transactions.
     * Pruned nodes may have entries where B is missing data.
     */
    std::multimap<CBlockIndex*, CBlockIndex*>& mapBlocksUnlinked = g_chainstate.mapBlocksUnlinked;

    CCriticalSection cs_LastBlockFile;
    std::vector<CBlockFileInfo> vinfoBlockFile;
    int nLastBlockFile = 0;
    /** Global flag to indicate we should check to see if there are
     *  block/undo files that should be deleted.  Set on startup
     *  or if we allocate more file space when we're in prune mode
     */
    bool fCheckForPruning = false;

    /** Dirty block index entries. */
    std::set<CBlockIndex*> setDirtyBlockIndex;

    /** Dirty block file entries. */
    std::set<int> setDirtyFileInfo;
} // anon namespace

CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator)
{
    // Find the first block the caller has in the main chain
    for (const uint256& hash : locator.vHave) {
        BlockMap::iterator mi = mapBlockIndex.find(hash);
        if (mi != mapBlockIndex.end())
        {
            CBlockIndex* pindex = (*mi).second;
            if (chain.Contains(pindex))
                return pindex;
            if (pindex->GetAncestor(chain.Height()) == chain.Tip()) {
                return chain.Tip();
            }
        }
    }
    return chain.Genesis();
}

std::unique_ptr<CCoinsViewDB> pcoinsdbview;
std::unique_ptr<CCoinsViewCache> pcoinsTip;
std::unique_ptr<CBlockTreeDB> pblocktree;

enum FlushStateMode {
    FLUSH_STATE_NONE,
    FLUSH_STATE_IF_NEEDED,
    FLUSH_STATE_PERIODIC,
    FLUSH_STATE_ALWAYS
};

// See definition for documentation
static bool FlushStateToDisk(const CChainParams& chainParams, CValidationState &state, FlushStateMode mode, int nManualPruneHeight=0);
static void FindFilesToPruneManual(std::set<int>& setFilesToPrune, int nManualPruneHeight);
static void FindFilesToPrune(std::set<int>& setFilesToPrune, uint64_t nPruneAfterHeight);
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, BlockTxnsPtr _connectingBlockTxns, std::vector<CScriptCheck> *pvChecks = nullptr);
static FILE* OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly = false);

char ASSETCHAINS_SYMBOL[65] = { "SFUSD" };

UniValue smartusd_snapshot(int top)
{
    LOCK(cs_main);
    int64_t total = -1;
    UniValue result(UniValue::VOBJ);

    if (fAddressIndex) {
	    if ( pblocktree != 0 ) {
		result = pblocktree->Snapshot(top);
	    } else {
		LogPrintf("null pblocktree start with -addressindex=1\n");
	    }
    } else {
	    LogPrintf("getsnapshot requires -addressindex=1\n");
    }
    return(result);
}

bool CheckFinalTx(const CTransaction &tx, int flags)
{
    AssertLockHeld(cs_main);

    // By convention a negative value for flags indicates that the
    // current network-enforced consensus rules should be used. In
    // a future soft-fork scenario that would mean checking which
    // rules would be enforced for the next block and setting the
    // appropriate flags. At the present time no soft-forks are
    // scheduled, so no flags are set.
    flags = std::max(flags, 0);

    // CheckFinalTx() uses chainActive.Height()+1 to evaluate
    // nLockTime because when IsFinalTx() is called within
    // CBlock::AcceptBlock(), the height of the block *being*
    // evaluated is what is used. Thus if we want to know if a
    // transaction can be part of the *next* block, we need to call
    // IsFinalTx() with one more than chainActive.Height().
    const int nBlockHeight = chainActive.Height() + 1;

    // BIP113 requires that time-locked transactions have nLockTime set to
    // less than the median time of the previous block they're contained in.
    // When the next block is created its previous block will be the current
    // chain tip, so we use that to calculate the median time passed to
    // IsFinalTx() if LOCKTIME_MEDIAN_TIME_PAST is set.
    const int64_t nBlockTime = (flags & LOCKTIME_MEDIAN_TIME_PAST)
                             ? chainActive.Tip()->GetMedianTimePast()
                             : GetAdjustedTime();

    return IsFinalTx(tx, nBlockHeight, nBlockTime);
}

bool TestLockPointValidity(const LockPoints* lp)
{
    AssertLockHeld(cs_main);
    assert(lp);
    // If there are relative lock times then the maxInputBlock will be set
    // If there are no relative lock times, the LockPoints don't depend on the chain
    if (lp->maxInputBlock) {
        // Check whether chainActive is an extension of the block at which the LockPoints
        // calculation was valid.  If not LockPoints are no longer valid
        if (!chainActive.Contains(lp->maxInputBlock)) {
            return false;
        }
    }

    // LockPoints still valid
    return true;
}

bool CheckSequenceLocks(const CTransaction &tx, int flags, LockPoints* lp, bool useExistingLockPoints)
{
    AssertLockHeld(cs_main);
    AssertLockHeld(mempool.cs);

    CBlockIndex* tip = chainActive.Tip();
    assert(tip != nullptr);

    CBlockIndex index;
    index.pprev = tip;
    // CheckSequenceLocks() uses chainActive.Height()+1 to evaluate
    // height based locks because when SequenceLocks() is called within
    // ConnectBlock(), the height of the block *being*
    // evaluated is what is used.
    // Thus if we want to know if a transaction can be part of the
    // *next* block, we need to use one more than chainActive.Height()
    index.nHeight = tip->nHeight + 1;

    std::pair<int, int64_t> lockPair;
    if (useExistingLockPoints) {
        assert(lp);
        lockPair.first = lp->height;
        lockPair.second = lp->time;
    }
    else {
        // pcoinsTip contains the UTXO set for chainActive.Tip()
        CCoinsViewMemPool viewMemPool(pcoinsTip.get(), mempool);
        std::vector<int> prevheights;
        prevheights.resize(tx.vin.size());
        for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
            const CTxIn& txin = tx.vin[txinIndex];
            Coin coin;
            if (!viewMemPool.GetCoin(txin.prevout, coin)) {
                return error("%s: Missing input", __func__);
            }
            if (coin.nHeight == MEMPOOL_HEIGHT) {
                // Assume all mempool transaction confirm in the next block
                prevheights[txinIndex] = tip->nHeight + 1;
            } else {
                prevheights[txinIndex] = coin.nHeight;
            }
        }
        lockPair = CalculateSequenceLocks(tx, flags, &prevheights, index);
        if (lp) {
            lp->height = lockPair.first;
            lp->time = lockPair.second;
            // Also store the hash of the block with the highest height of
            // all the blocks which have sequence locked prevouts.
            // This hash needs to still be on the chain
            // for these LockPoint calculations to be valid
            // Note: It is impossible to correctly calculate a maxInputBlock
            // if any of the sequence locked inputs depend on unconfirmed txs,
            // except in the special case where the relative lock time/height
            // is 0, which is equivalent to no sequence lock. Since we assume
            // input height of tip+1 for mempool txs and test the resulting
            // lockPair from CalculateSequenceLocks against tip+1.  We know
            // EvaluateSequenceLocks will fail if there was a non-zero sequence
            // lock on a mempool input, so we can use the return value of
            // CheckSequenceLocks to indicate the LockPoints validity
            int maxInputHeight = 0;
            for (int height : prevheights) {
                // Can ignore mempool inputs since we'll fail if they had non-zero locks
                if (height != tip->nHeight+1) {
                    maxInputHeight = std::max(maxInputHeight, height);
                }
            }
            lp->maxInputBlock = tip->GetAncestor(maxInputHeight);
        }
    }
    return EvaluateSequenceLocks(index, lockPair);
}

// Returns the script flags which should be checked for a given block
static unsigned int GetBlockScriptFlags(const CBlockIndex* pindex, const Consensus::Params& chainparams);

static void LimitMempoolSize(CTxMemPool& pool, size_t limit, unsigned long age) {
    int expired = pool.Expire(GetTime() - age);
    if (expired != 0) {
        LogPrint(BCLog::MEMPOOL, "Expired %i transactions from the memory pool\n", expired);
    }

    std::vector<COutPoint> vNoSpendsRemaining;
    pool.TrimToSize(limit, &vNoSpendsRemaining);
    for (const COutPoint& removed : vNoSpendsRemaining)
        pcoinsTip->Uncache(removed);
}

/** Convert CValidationState to a human-readable message for logging */
std::string FormatStateMessage(const CValidationState &state)
{
    return strprintf("%s%s (code %i)",
        state.GetRejectReason(),
        state.GetDebugMessage().empty() ? "" : ", "+state.GetDebugMessage(),
        state.GetRejectCode());
}

static bool IsCurrentForFeeEstimation()
{
    AssertLockHeld(cs_main);
    if (IsInitialBlockDownload())
        return false;
    if (chainActive.Tip()->GetBlockTime() < (GetTime() - MAX_FEE_ESTIMATION_TIP_AGE))
        return false;
    if (chainActive.Height() < pindexBestHeader->nHeight - 1)
        return false;
    return true;
}

/* Make mempool consistent after a reorg, by re-adding or recursively erasing
 * disconnected block transactions from the mempool, and also removing any
 * other transactions from the mempool that are no longer valid given the new
 * tip/height.
 *
 * Note: we assume that disconnectpool only contains transactions that are NOT
 * confirmed in the current chain nor already in the mempool (otherwise,
 * in-mempool descendants of such transactions would be removed).
 *
 * Passing fAddToMempool=false will skip trying to add the transactions back,
 * and instead just erase from the mempool as needed.
 */

void UpdateMempoolForReorg(DisconnectedBlockTransactions &disconnectpool, bool fAddToMempool)
{
    AssertLockHeld(cs_main);
    std::vector<uint256> vHashUpdate;
    // disconnectpool's insertion_order index sorts the entries from
    // oldest to newest, but the oldest entry will be the last tx from the
    // latest mined block that was disconnected.
    // Iterate disconnectpool in reverse, so that we add transactions
    // back to the mempool starting with the earliest transaction that had
    // been previously seen in a block.
    auto it = disconnectpool.queuedTx.get<insertion_order>().rbegin();
    while (it != disconnectpool.queuedTx.get<insertion_order>().rend()) {
        // ignore validation errors in resurrected transactions
        CValidationState stateDummy;
        if (!fAddToMempool || (*it)->IsCoinBase() ||
            !AcceptToMemoryPool(mempool, stateDummy, *it, nullptr /* pfMissingInputs */,
                                nullptr /* plTxnReplaced */, true /* bypass_limits */, 0 /* nAbsurdFee */)) {
            // If the transaction doesn't make it in to the mempool, remove any
            // transactions that depend on it (which would now be orphans).
            mempool.removeRecursive(**it, MemPoolRemovalReason::REORG);
        } else if (mempool.exists((*it)->GetHash())) {
            vHashUpdate.push_back((*it)->GetHash());
        }
        ++it;
    }
    disconnectpool.queuedTx.clear();
    // AcceptToMemoryPool/addUnchecked all assume that new mempool entries have
    // no in-mempool children, which is generally not true when adding
    // previously-confirmed transactions back to the mempool.
    // UpdateTransactionsFromBlock finds descendants of any transactions in
    // the disconnectpool that were added back and cleans up the mempool state.
    mempool.UpdateTransactionsFromBlock(vHashUpdate);

    // We also need to remove any now-immature transactions
    mempool.removeForReorg(pcoinsTip.get(), chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
    // Re-limit mempool size, in case we added any transactions
    LimitMempoolSize(mempool, gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, gArgs.GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
}

// Used to avoid mempool polluting consensus critical paths if CCoinsViewMempool
// were somehow broken and returning the wrong scriptPubKeys
static bool CheckInputsFromMempoolAndCache(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &view, CTxMemPool& pool,
                 unsigned int flags, bool cacheSigStore, PrecomputedTransactionData& txdata) {
    AssertLockHeld(cs_main);

    // pool.cs should be locked already, but go ahead and re-take the lock here
    // to enforce that mempool doesn't change between when we check the view
    // and when we actually call through to CheckInputs
    LOCK(pool.cs);

    assert(!tx.IsCoinBase());
    for (const CTxIn& txin : tx.vin) {
        const Coin& coin = view.AccessCoin(txin.prevout);

        // At this point we haven't actually checked if the coins are all
        // available (or shouldn't assume we have, since CheckInputs does).
        // So we just return failure if the inputs are not available here,
        // and then only have to check equivalence for available inputs.
        if (coin.IsSpent()) return false;

        const CTransactionRef& txFrom = pool.get(txin.prevout.hash);
        if (txFrom) {
            assert(txFrom->GetHash() == txin.prevout.hash);
            assert(txFrom->vout.size() > txin.prevout.n);
            assert(txFrom->vout[txin.prevout.n] == coin.out);
        } else {
            const Coin& coinFromDisk = pcoinsTip->AccessCoin(txin.prevout);
            assert(!coinFromDisk.IsSpent());
            assert(coinFromDisk.out == coin.out);
        }
    }

    return CheckInputs(tx, state, view, true, flags, cacheSigStore, true, txdata, NULL);
}

static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool& pool, CValidationState& state, const CTransactionRef& ptx,
                              bool* pfMissingInputs, int64_t nAcceptTime, std::list<CTransactionRef>* plTxnReplaced,
                              bool bypass_limits, const CAmount& nAbsurdFee, std::vector<COutPoint>& coins_to_uncache)
{
    const CTransaction& tx = *ptx;
    const uint256 hash = tx.GetHash();
    int flag=0;
    AssertLockHeld(cs_main);
    LOCK(pool.cs); // mempool "read lock" (held through GetMainSignals().TransactionAddedToMempool())
    if (pfMissingInputs) {
        *pfMissingInputs = false;
    }

    if (!CheckTransaction(tx, state))
        return false; // state filled in by CheckTransaction

    // Coinbase is only valid in a block, not as a loose transaction
    if (tx.IsCoinBase())
        return state.DoS(100, false, REJECT_INVALID, "coinbase");

    // Reject transactions with witness before segregated witness activates (override with -prematurewitness)
    bool witnessEnabled = IsWitnessEnabled(chainActive.Tip(), chainparams.GetConsensus());
    if (!gArgs.GetBoolArg("-prematurewitness", false) && tx.HasWitness() && !witnessEnabled) {
        return state.DoS(0, false, REJECT_NONSTANDARD, "no-witness-yet", true);
    }

    // Rather not work on nonstandard transactions (unless -testnet/-regtest)
    std::string reason;
    if (fRequireStandard && !IsStandardTx(tx, reason, witnessEnabled))
        return state.DoS(0, false, REJECT_NONSTANDARD, reason);

    // Do not work on transactions that are too small.
    // A transaction with 1 segwit input and 1 P2WPHK output has non-witness size of 82 bytes.
    // Transactions smaller than this are not relayed to reduce unnecessary malloc overhead.
    if (::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) < MIN_STANDARD_TX_NONWITNESS_SIZE)
        return state.DoS(0, false, REJECT_NONSTANDARD, "tx-size-small");

    // Only accept nLockTime-using transactions that can be mined in the next
    // block; we don't want our mempool filled up with transactions that can't
    // be mined yet.
    if (!CheckFinalTx(tx, STANDARD_LOCKTIME_VERIFY_FLAGS))
        return state.DoS(0, false, REJECT_NONSTANDARD, "non-final");

    // is it already in the memory pool?
    if (pool.exists(hash)) {
        return state.Invalid(false, REJECT_DUPLICATE, "txn-already-in-mempool");
    }

    // Check for conflicts with in-memory transactions
    std::set<uint256> setConflicts;
    for (const CTxIn &txin : tx.vin)
    {
        auto itConflicting = pool.mapNextTx.find(txin.prevout);
        if (itConflicting != pool.mapNextTx.end())
        {
            const CTransaction *ptxConflicting = itConflicting->second;
            if (!setConflicts.count(ptxConflicting->GetHash()))
            {
                // Allow opt-out of transaction replacement by setting
                // nSequence > MAX_BIP125_RBF_SEQUENCE (SEQUENCE_FINAL-2) on all inputs.
                //
                // SEQUENCE_FINAL-1 is picked to still allow use of nLockTime by
                // non-replaceable transactions. All inputs rather than just one
                // is for the sake of multi-party protocols, where we don't
                // want a single party to be able to disable replacement.
                //
                // The opt-out ignores descendants as anyone relying on
                // first-seen mempool behavior should be checking all
                // unconfirmed ancestors anyway; doing otherwise is hopelessly
                // insecure.
                bool fReplacementOptOut = true;
                if (fEnableReplacement)
                {
                    for (const CTxIn &_txin : ptxConflicting->vin)
                    {
                        if (_txin.nSequence <= MAX_BIP125_RBF_SEQUENCE)
                        {
                            fReplacementOptOut = false;
                            break;
                        }
                    }
                }
                if (fReplacementOptOut) {
                    return state.Invalid(false, REJECT_DUPLICATE, "txn-mempool-conflict");
                }

                setConflicts.insert(ptxConflicting->GetHash());
            }
        }
    }


    {
        CCoinsView dummy;
        CCoinsViewCache view(&dummy);

        LockPoints lp;
        CCoinsViewMemPool viewMemPool(pcoinsTip.get(), pool);
        view.SetBackend(viewMemPool);

        if (tx.IsCoinImport() || tx.IsPegsImport())
        {
            // Inverse of normal case; if input exists, it's been spent
            if (ExistsImportTombstone(tx, view))
                return state.Invalid(false, REJECT_DUPLICATE, "import tombstone exists");
        }
        else
        {
            // do all inputs exist?
            for (const CTxIn txin : tx.vin) {
                if (!pcoinsTip->HaveCoinInCache(txin.prevout)) {
                    coins_to_uncache.push_back(txin.prevout);
                }
                if (!view.HaveCoin(txin.prevout)) {
                    // Are inputs missing because we already have the tx?
                    for (size_t out = 0; out < tx.vout.size(); out++) {
                        // Optimistically just do efficient check of cache for outputs
                        if (pcoinsTip->HaveCoinInCache(COutPoint(hash, out))) {
                            return state.Invalid(false, REJECT_DUPLICATE, "txn-already-known");
                        }
                    }
                    // Otherwise assume this might be an orphan tx for which we just haven't seen parents yet
                    if (pfMissingInputs) {
                        *pfMissingInputs = true;
                    }
                    return false; // fMissingInputs and !state.IsInvalid() is used to detect this condition, don't set state.Invalid()
                }
            }
        }

        // Bring the best block into scope
        view.GetBestBlock();

        // we have all inputs cached now, so switch back to dummy, so we don't need to keep lock on mempool
        view.SetBackend(dummy);

        // Only accept BIP68 sequence locked transactions that can be mined in the next
        // block; we don't want our mempool filled up with transactions that can't
        // be mined yet.
        // Must keep pool.cs for this unless we change CheckSequenceLocks to take a
        // CoinsViewCache instead of create its own
        if (!CheckSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp))
            return state.DoS(0, false, REJECT_NONSTANDARD, "non-BIP68-final");

        CAmount nFees = 0;
        if (!Consensus::CheckTxInputs(tx, state, view, GetSpendHeight(view), nFees)) {
            return error("%s: Consensus::CheckTxInputs: %s, %s", __func__, tx.GetHash().ToString(), FormatStateMessage(state));
        }

        // Check for non-standard pay-to-script-hash in inputs
        if (fRequireStandard && !AreInputsStandard(tx, view))
            return state.Invalid(false, REJECT_NONSTANDARD, "bad-txns-nonstandard-inputs");

        // Check for non-standard witness in P2WSH
        if (tx.HasWitness() && fRequireStandard && !IsWitnessStandard(tx, view))
            return state.DoS(0, false, REJECT_NONSTANDARD, "bad-witness-nonstandard", true);

        int64_t nSigOpsCost = GetTransactionSigOpCost(tx, view, STANDARD_SCRIPT_VERIFY_FLAGS);

        // nModifiedFees includes any fee deltas from PrioritiseTransaction
        CAmount nModifiedFees = nFees;
        pool.ApplyDelta(hash, nModifiedFees);

        // Keep track of transactions that spend a coinbase, which we re-scan
        // during reorgs to ensure COINBASE_MATURITY is still met.
        bool fSpendsCoinbase = false;
        if (!tx.IsCoinImport() && !tx.IsPegsImport()) {
            for (const CTxIn &txin : tx.vin) {
                const Coin &coin = view.AccessCoin(txin.prevout);
                if (coin.IsCoinBase()) {
                    fSpendsCoinbase = true;
                    break;
                }
            }
        }

        CTxMemPoolEntry entry(ptx, nFees, nAcceptTime, chainActive.Height(),
                              fSpendsCoinbase, nSigOpsCost, lp);
        unsigned int nSize = entry.GetTxSize();

        // Check that the transaction doesn't have an excessive number of
        // sigops, making it impossible to mine. Since the coinbase transaction
        // itself can contain sigops MAX_STANDARD_TX_SIGOPS is less than
        // MAX_BLOCK_SIGOPS; we still consider this an invalid rather than
        // merely non-standard transaction.
        if (nSigOpsCost > MAX_STANDARD_TX_SIGOPS_COST)
            return state.DoS(0, false, REJECT_NONSTANDARD, "bad-txns-too-many-sigops", false,
                strprintf("%d", nSigOpsCost));

        CAmount mempoolRejectFee = pool.GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFee(nSize);
        if (!bypass_limits && mempoolRejectFee > 0 && nModifiedFees < mempoolRejectFee && !tx.IsCoinImport() && !tx.IsPegsImport()) {
            return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool min fee not met", false, strprintf("%d < %d", nFees, mempoolRejectFee));
        }

        // No transactions are allowed below minRelayTxFee except from disconnected blocks
        if (!bypass_limits && nModifiedFees < ::minRelayTxFee.GetFee(nSize) && !tx.IsCoinImport() && !tx.IsPegsImport()) {
            return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "min relay fee not met");
        }

        if (!tx.IsCoinImport() && !tx.IsPegsImport() && nAbsurdFee && nFees > nAbsurdFee)
            return state.Invalid(false,
                REJECT_HIGHFEE, "absurdly-high-fee",
                strprintf("%d > %d", nFees, nAbsurdFee));

        // Calculate in-mempool ancestors, up to a limit.
        CTxMemPool::setEntries setAncestors;
        size_t nLimitAncestors = gArgs.GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
        size_t nLimitAncestorSize = gArgs.GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT)*1000;
        size_t nLimitDescendants = gArgs.GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT);
        size_t nLimitDescendantSize = gArgs.GetArg("-limitdescendantsize", DEFAULT_DESCENDANT_SIZE_LIMIT)*1000;
        std::string errString;
        if (!pool.CalculateMemPoolAncestors(entry, setAncestors, nLimitAncestors, nLimitAncestorSize, nLimitDescendants, nLimitDescendantSize, errString)) {
            return state.DoS(0, false, REJECT_NONSTANDARD, "too-long-mempool-chain", false, errString);
        }

        // A transaction that spends outputs that would be replaced by it is invalid. Now
        // that we have the set of all ancestors we can detect this
        // pathological case by making sure setConflicts and setAncestors don't
        // intersect.
        for (CTxMemPool::txiter ancestorIt : setAncestors)
        {
            const uint256 &hashAncestor = ancestorIt->GetTx().GetHash();
            if (setConflicts.count(hashAncestor))
            {
                return state.DoS(10, false,
                                 REJECT_INVALID, "bad-txns-spends-conflicting-tx", false,
                                 strprintf("%s spends conflicting transaction %s",
                                           hash.ToString(),
                                           hashAncestor.ToString()));
            }
        }

        // Check if it's economically rational to mine this transaction rather
        // than the ones it replaces.
        CAmount nConflictingFees = 0;
        size_t nConflictingSize = 0;
        uint64_t nConflictingCount = 0;
        CTxMemPool::setEntries allConflicting;

        // If we don't hold the lock allConflicting might be incomplete; the
        // subsequent RemoveStaged() and addUnchecked() calls don't guarantee
        // mempool consistency for us.
        const bool fReplacementTransaction = setConflicts.size();
        if (fReplacementTransaction)
        {
            CFeeRate newFeeRate(nModifiedFees, nSize);
            std::set<uint256> setConflictsParents;
            const int maxDescendantsToVisit = 100;
            CTxMemPool::setEntries setIterConflicting;
            for (const uint256 &hashConflicting : setConflicts)
            {
                CTxMemPool::txiter mi = pool.mapTx.find(hashConflicting);
                if (mi == pool.mapTx.end())
                    continue;

                // Save these to avoid repeated lookups
                setIterConflicting.insert(mi);

                // Don't allow the replacement to reduce the feerate of the
                // mempool.
                //
                // We usually don't want to accept replacements with lower
                // feerates than what they replaced as that would lower the
                // feerate of the next block. Requiring that the feerate always
                // be increased is also an easy-to-reason about way to prevent
                // DoS attacks via replacements.
                //
                // The mining code doesn't (currently) take children into
                // account (CPFP) so we only consider the feerates of
                // transactions being directly replaced, not their indirect
                // descendants. While that does mean high feerate children are
                // ignored when deciding whether or not to replace, we do
                // require the replacement to pay more overall fees too,
                // mitigating most cases.
                CFeeRate oldFeeRate(mi->GetModifiedFee(), mi->GetTxSize());
                if (newFeeRate <= oldFeeRate)
                {
                    return state.DoS(0, false,
                            REJECT_INSUFFICIENTFEE, "insufficient fee", false,
                            strprintf("rejecting replacement %s; new feerate %s <= old feerate %s",
                                  hash.ToString(),
                                  newFeeRate.ToString(),
                                  oldFeeRate.ToString()));
                }

                for (const CTxIn &txin : mi->GetTx().vin)
                {
                    setConflictsParents.insert(txin.prevout.hash);
                }

                nConflictingCount += mi->GetCountWithDescendants();
            }
            // This potentially overestimates the number of actual descendants
            // but we just want to be conservative to avoid doing too much
            // work.
            if (nConflictingCount <= maxDescendantsToVisit) {
                // If not too many to replace, then calculate the set of
                // transactions that would have to be evicted
                for (CTxMemPool::txiter it : setIterConflicting) {
                    pool.CalculateDescendants(it, allConflicting);
                }
                for (CTxMemPool::txiter it : allConflicting) {
                    nConflictingFees += it->GetModifiedFee();
                    nConflictingSize += it->GetTxSize();
                }
            } else {
                return state.DoS(0, false,
                        REJECT_NONSTANDARD, "too many potential replacements", false,
                        strprintf("rejecting replacement %s; too many potential replacements (%d > %d)\n",
                            hash.ToString(),
                            nConflictingCount,
                            maxDescendantsToVisit));
            }

            for (unsigned int j = 0; j < tx.vin.size(); j++)
            {
                // We don't want to accept replacements that require low
                // feerate junk to be mined first. Ideally we'd keep track of
                // the ancestor feerates and make the decision based on that,
                // but for now requiring all new inputs to be confirmed works.
                if (!setConflictsParents.count(tx.vin[j].prevout.hash))
                {
                    // Rather than check the UTXO set - potentially expensive -
                    // it's cheaper to just check if the new input refers to a
                    // tx that's in the mempool.
                    if (pool.mapTx.find(tx.vin[j].prevout.hash) != pool.mapTx.end())
                        return state.DoS(0, false,
                                         REJECT_NONSTANDARD, "replacement-adds-unconfirmed", false,
                                         strprintf("replacement %s adds unconfirmed input, idx %d",
                                                  hash.ToString(), j));
                }
            }

            // The replacement must pay greater fees than the transactions it
            // replaces - if we did the bandwidth used by those conflicting
            // transactions would not be paid for.
            if (nModifiedFees < nConflictingFees)
            {
                return state.DoS(0, false,
                                 REJECT_INSUFFICIENTFEE, "insufficient fee", false,
                                 strprintf("rejecting replacement %s, less fees than conflicting txs; %s < %s",
                                          hash.ToString(), FormatMoney(nModifiedFees), FormatMoney(nConflictingFees)));
            }

            // Finally in addition to paying more fees than the conflicts the
            // new transaction must pay for its own bandwidth.
            CAmount nDeltaFees = nModifiedFees - nConflictingFees;
            if (nDeltaFees < ::incrementalRelayFee.GetFee(nSize))
            {
                return state.DoS(0, false,
                        REJECT_INSUFFICIENTFEE, "insufficient fee", false,
                        strprintf("rejecting replacement %s, not enough additional fees to relay; %s < %s",
                              hash.ToString(),
                              FormatMoney(nDeltaFees),
                              FormatMoney(::incrementalRelayFee.GetFee(nSize))));
            }
        }

        unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS;
        if (!chainparams.RequireStandard()) {
            scriptVerifyFlags = gArgs.GetArg("-promiscuousmempoolflags", scriptVerifyFlags);
        }

        // Check against previous transactions
        // This is done last to help prevent CPU exhaustion denial-of-service attacks.
        PrecomputedTransactionData txdata(tx);
        if (!CheckInputs(tx, state, view, true, scriptVerifyFlags, true, false, txdata, NULL)) {
            // SCRIPT_VERIFY_CLEANSTACK requires SCRIPT_VERIFY_WITNESS, so we
            // need to turn both off, and compare against just turning off CLEANSTACK
            // to see if the failure is specifically due to witness validation.
            CValidationState stateDummy; // Want reported failures to be from first CheckInputs
            if (!tx.HasWitness() && CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, false, txdata, NULL) &&
                !CheckInputs(tx, stateDummy, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, false, txdata, NULL)) {
                // Only the witness is missing, so the transaction itself may be fine.
                state.SetCorruptionPossible();
            }
            return false; // state filled in by CheckInputs
        }

        // Check again against the current block tip's script verification
        // flags to cache our script execution flags. This is, of course,
        // useless if the next block has different script flags from the
        // previous one, but because the cache tracks script flags for us it
        // will auto-invalidate and we'll just have a few blocks of extra
        // misses on soft-fork activation.
        //
        // This is also useful in case of bugs in the standard flags that cause
        // transactions to pass as valid when they're actually invalid. For
        // instance the STRICTENC flag was incorrectly allowing certain
        // CHECKSIG NOT scripts to pass, even though they were invalid.
        //
        // There is a similar check in CreateNewBlock() to prevent creating
        // invalid blocks (using TestBlockValidity), however allowing such
        // transactions into the mempool can be exploited as a DoS attack.
        unsigned int currentBlockScriptVerifyFlags = GetBlockScriptFlags(chainActive.Tip(), Params().GetConsensus());
        if (!CheckInputsFromMempoolAndCache(tx, state, view, pool, currentBlockScriptVerifyFlags, true, txdata))
        {
            // If we're using promiscuousmempoolflags, we may hit this normally
            // Check if current block has some flags that scriptVerifyFlags
            // does not before printing an ominous warning
            if (!(~scriptVerifyFlags & currentBlockScriptVerifyFlags)) {
                return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed against latest-block but not STANDARD flags %s, %s",
                    __func__, hash.ToString(), FormatStateMessage(state));
            } else {
                if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true, false, txdata, NULL)) {
                    return error("%s: ConnectInputs failed against MANDATORY but not STANDARD flags due to promiscuous mempool %s, %s",
                        __func__, hash.ToString(), FormatStateMessage(state));
                } else {
                    LogPrintf("Warning: -promiscuousmempool flags set to not include currently enforced soft forks, this may break mining or otherwise cause instability!\n");
                }
            }
        }

        /* not used, SCRIPT_VERIFY_HEAVY_CC_EVAL used instead
        if ( SMARTUSD_CONNECTING <= 0 && chainActive.LastTip() != 0 )
        {
            flag = 1;
            SMARTUSD_CONNECTING = (1<<30) + (int32_t)chainActive.LastTip()->GetHeight() + 1;
        }

        if ( flag != 0 ) SMARTUSD_CONNECTING = -1; */

        // Remove conflicting transactions from the mempool
        for (const CTxMemPool::txiter it : allConflicting)
        {
            LogPrint(BCLog::MEMPOOL, "replacing tx %s with %s for %s BTC additional fees, %d delta bytes\n",
                    it->GetTx().GetHash().ToString(),
                    hash.ToString(),
                    FormatMoney(nModifiedFees - nConflictingFees),
                    (int)nSize - (int)nConflictingSize);
            if (plTxnReplaced)
                plTxnReplaced->push_back(it->GetSharedTx());
        }
        pool.RemoveStaged(allConflicting, false, MemPoolRemovalReason::REPLACED);

        // This transaction should only count for fee estimation if:
        // - it isn't a BIP 125 replacement transaction (may not be widely supported)
        // - it's not being readded during a reorg which bypasses typical mempool fee limits
        // - the node is not behind
        // - the transaction is not dependent on any other transactions in the mempool
        bool validForFeeEstimation = !fReplacementTransaction && !bypass_limits && IsCurrentForFeeEstimation() && pool.HasNoInputsOf(tx);

        // Store transaction in memory
        pool.addUnchecked(hash, entry, setAncestors, validForFeeEstimation);

        // Add memory address index
        if (fAddressIndex) {
            pool.addAddressIndex(entry, view);
        }

        // Add memory spent index
        if (fSpentIndex) {
            pool.addSpentIndex(entry, view);
        }

        // trim mempool and check if tx was trimmed
        if (!bypass_limits) {
            LimitMempoolSize(pool, gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, gArgs.GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
            if (!pool.exists(hash))
                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool full");
        }
    }

    GetMainSignals().TransactionAddedToMempool(ptx);

    return true;
}

/** (try to) add transaction to memory pool with a specified acceptance time **/
static bool AcceptToMemoryPoolWithTime(const CChainParams& chainparams, CTxMemPool& pool, CValidationState &state, const CTransactionRef &tx,
                        bool* pfMissingInputs, int64_t nAcceptTime, std::list<CTransactionRef>* plTxnReplaced,
                        bool bypass_limits, const CAmount nAbsurdFee)
{
    std::vector<COutPoint> coins_to_uncache;
    bool res = AcceptToMemoryPoolWorker(chainparams, pool, state, tx, pfMissingInputs, nAcceptTime, plTxnReplaced, bypass_limits, nAbsurdFee, coins_to_uncache);
    if (!res) {
        for (const COutPoint& hashTx : coins_to_uncache)
            pcoinsTip->Uncache(hashTx);
    }
    // After we've (potentially) uncached entries, ensure our coins cache is still within its size limits
    CValidationState stateDummy;
    FlushStateToDisk(chainparams, stateDummy, FLUSH_STATE_PERIODIC);
    return res;
}

bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransactionRef &tx,
                        bool* pfMissingInputs, std::list<CTransactionRef>* plTxnReplaced,
                        bool bypass_limits, const CAmount nAbsurdFee)
{
    const CChainParams& chainparams = Params();
    return AcceptToMemoryPoolWithTime(chainparams, pool, state, tx, pfMissingInputs, GetTime(), plTxnReplaced, bypass_limits, nAbsurdFee);
}

bool GetTimestampIndex(const unsigned int &high, const unsigned int &low, const bool fActiveOnly, std::vector<std::pair<uint256, unsigned int> > &hashes)
{
    if (!fTimestampIndex)
        return error("Timestamp index not enabled");

    if (!pblocktree->ReadTimestampIndex(high, low, fActiveOnly, hashes))
        return error("Unable to get hashes for timestamps");

    return true;
}

bool GetSpentIndex(CSpentIndexKey &key, CSpentIndexValue &value)
{
    if (!fSpentIndex)
        return false;

    if (mempool.getSpentIndex(key, value))
        return true;

    if (!pblocktree->ReadSpentIndex(key, value))
        return false;

    return true;
}

bool GetAddressIndex(uint160 addressHash, int type,
                     std::vector<std::pair<CAddressIndexKey, CAmount> > &addressIndex, int start, int end)
{
    if (!fAddressIndex)
        return error("address index not enabled");

    if (!pblocktree->ReadAddressIndex(addressHash, type, addressIndex, start, end))
        return error("unable to get txids for address");

    return true;
}

bool GetAddressUnspent(uint160 addressHash, int type,
                       std::vector<std::pair<CAddressUnspentKey, CAddressUnspentValue> > &unspentOutputs)
{
    if (!fAddressIndex)
        return error("address index not enabled");

    if (!pblocktree->ReadAddressUnspentIndex(addressHash, type, unspentOutputs))
        return error("unable to get txids for address");

    return true;
}

/**
 * Return transaction in txOut, and if it was found inside a block, its hash is placed in hashBlock.
 * If blockIndex is provided, the transaction is fetched from the corresponding block.
 */
bool GetTransaction(const uint256& hash, CTransactionRef& txOut, const Consensus::Params& consensusParams, uint256& hashBlock, bool fAllowSlow, CBlockIndex* blockIndex)
{
    CBlockIndex* pindexSlow = blockIndex;

    LOCK(cs_main);

    if (!blockIndex) {
        CTransactionRef ptx = mempool.get(hash);
        if (ptx) {
            txOut = ptx;
            return true;
        }

        if (fTxIndex) {
            CDiskTxPos postx;
            if (pblocktree->ReadTxIndex(hash, postx)) {
                CAutoFile file(OpenBlockFile(postx, true), SER_DISK, CLIENT_VERSION);
                if (file.IsNull())
                    return error("%s: OpenBlockFile failed", __func__);
                CBlockHeader header;
                try {
                    file >> header;
                    fseek(file.Get(), postx.nTxOffset, SEEK_CUR);
                    file >> txOut;
                } catch (const std::exception& e) {
                    return error("%s: Deserialize or I/O error - %s", __func__, e.what());
                }
                hashBlock = header.GetHash();
                if (txOut->GetHash() != hash)
                    return error("%s: txid mismatch", __func__);
                return true;
            }

            // transaction not found in index, nothing more can be done
            return false;
        }

        if (fAllowSlow) { // use coin database to locate block that contains transaction, and scan it
            const Coin& coin = AccessByTxid(*pcoinsTip, hash);
            if (!coin.IsSpent()) pindexSlow = chainActive[coin.nHeight];
        }
    }

    if (pindexSlow) {
        CBlock block;
        if (ReadBlockFromDisk(block, pindexSlow, consensusParams)) {
            for (const auto& tx : block.vtx) {
                if (tx->GetHash() == hash) {
                    txOut = tx;
                    hashBlock = pindexSlow->GetBlockHash();
                    return true;
                }
            }
        }
    }

    return false;
}






//////////////////////////////////////////////////////////////////////////////
//
// CBlock and CBlockIndex
//

bool CheckProofOfWork(const CBlockHeader& block, const Consensus::Params& params)
{
    /* Except for legacy blocks with full version 1, ensure that
       the chain ID is correct.  Legacy blocks are not allowed since
       the merge-mining start, which is checked in AcceptBlockHeader
       where the height is known.  */
    if (!block.IsLegacy() && params.fStrictChainId
        && block.GetChainId() != params.nAuxpowChainId)
        return error("%s : block does not have our chain ID"
                     " (got %d, expected %d, full nVersion %d)",
                     __func__, block.GetChainId(),
                     params.nAuxpowChainId, block.nVersion);

    /* If there is no auxpow, just check the block hash.  */
    if (!block.auxpow)
    {
        if (block.IsAuxpow())
            return error("%s : no auxpow on block with auxpow version",
                         __func__);

        if (!CheckProofOfWork(block.GetHash(), block.nBits, params))
            return error("%s : non-AUX proof of work failed", __func__);

        return true;
    }

    /* We have auxpow.  Check it.  */

    if (!block.IsAuxpow())
        return error("%s : auxpow on block with non-auxpow version", __func__);

    /* Temporary check:  Disallow parent blocks with auxpow version.  This is
       for compatibility with the old client.  */
    /* FIXME: Remove this check with a hardfork later on.  */
    if (block.auxpow->getParentBlock().IsAuxpow())
        return error("%s : auxpow parent block has auxpow version", __func__);

    if (!block.auxpow->check(block.GetHash(), block.GetChainId(), params))
        return error("%s : AUX POW is not valid", __func__);
    if (!CheckProofOfWork(block.auxpow->getParentBlockHash(), block.nBits, params))
        return error("%s : AUX proof of work failed", __func__);

    return true;
}

static bool WriteBlockToDisk(const CBlock& block, CDiskBlockPos& pos, const CMessageHeader::MessageStartChars& messageStart)
{
    // Open history file to append
    CAutoFile fileout(OpenBlockFile(pos), SER_DISK, CLIENT_VERSION);
    if (fileout.IsNull())
        return error("WriteBlockToDisk: OpenBlockFile failed");

    // Write index header
    unsigned int nSize = GetSerializeSize(fileout, block);
    fileout << FLATDATA(messageStart) << nSize;

    // Write block
    long fileOutPos = ftell(fileout.Get());
    if (fileOutPos < 0)
        return error("WriteBlockToDisk: ftell failed");
    pos.nPos = (unsigned int)fileOutPos;
    fileout << block;

    return true;
}

/* Generic implementation of block reading that can handle
   both a block and its header.  */

template<typename T>
static bool ReadBlockOrHeader(T& block, const CDiskBlockPos& pos, const Consensus::Params& consensusParams)
{
    block.SetNull();

    // Open history file to read
    CAutoFile filein(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION);
    if (filein.IsNull())
        return error("ReadBlockFromDisk: OpenBlockFile failed for %s", pos.ToString());

    // Read block
    try {
        filein >> block;
    }
    catch (const std::exception& e) {
        return error("%s: Deserialize or I/O error - %s at %s", __func__, e.what(), pos.ToString());
    }

    // Check the header
    if (!CheckProofOfWork(block, consensusParams))
        return error("ReadBlockFromDisk: Errors in block header at %s", pos.ToString());

    return true;
}

template<typename T>
static bool ReadBlockOrHeader(T& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
{
    CDiskBlockPos blockPos;
    {
        LOCK(cs_main);
        blockPos = pindex->GetBlockPos();
    }

    if (!ReadBlockOrHeader(block, blockPos, consensusParams))
        return false;
    if (block.GetHash() != pindex->GetBlockHash())
        return error("ReadBlockFromDisk(CBlock&, CBlockIndex*): GetHash() doesn't match index for %s at %s",
                pindex->ToString(), pindex->GetBlockPos().ToString());
    return true;
}

bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos, const Consensus::Params& consensusParams)
{
    return ReadBlockOrHeader(block, pos, consensusParams);
}

bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
{
    return ReadBlockOrHeader(block, pindex, consensusParams);
}

bool ReadBlockHeaderFromDisk(CBlockHeader& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
{
    return ReadBlockOrHeader(block, pindex, consensusParams);
}

CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams)
{
    // currently we haven't any halvings (could be changed in future), fixed miner reward is 0 SFUSD per block (empty blocks)
    // this likely undergoing update with custom distribution algorithm and loan CC
    // pre-mint for SmartFi platform is in block from nheight 1
    CAmount nSubsidy = 0 * COIN;
    if (1 == nHeight) {
        nSubsidy = 90000000000LL * COIN ; // updated for SmartFi (SFUSD) relaunch
    }
    return nSubsidy;
}

bool IsInitialBlockDownload()
{
    // Once this function has returned false, it must remain false.
    static std::atomic<bool> latchToFalse{false};
    // Optimization: pre-test latch before taking the lock.
    if (latchToFalse.load(std::memory_order_relaxed))
        return false;

    LOCK(cs_main);
    if (latchToFalse.load(std::memory_order_relaxed))
        return false;
    if (fImporting || fReindex)
        return true;
    if (chainActive.Tip() == nullptr)
        return true;
    if (chainActive.Tip()->nChainWork < nMinimumChainWork)
        return true;
    if (chainActive.Tip()->GetBlockTime() < (GetTime() - nMaxTipAge))
        return true;
    LogPrintf("Leaving InitialBlockDownload (latching to false)\n");
    latchToFalse.store(true, std::memory_order_relaxed);
    return false;
}

CBlockIndex *pindexBestForkTip = nullptr, *pindexBestForkBase = nullptr;

static void AlertNotify(const std::string& strMessage)
{
    uiInterface.NotifyAlertChanged();
    std::string strCmd = gArgs.GetArg("-alertnotify", "");
    if (strCmd.empty()) return;

    // Alert text should be plain ascii coming from a trusted source, but to
    // be safe we first strip anything not in safeChars, then add single quotes around
    // the whole string before passing it to the shell:
    std::string singleQuote("'");
    std::string safeStatus = SanitizeString(strMessage);
    safeStatus = singleQuote+safeStatus+singleQuote;
    boost::replace_all(strCmd, "%s", safeStatus);

    boost::thread t(runCommand, strCmd); // thread runs free
}

static void CheckForkWarningConditions()
{
    AssertLockHeld(cs_main);
    // Before we get past initial download, we cannot reliably alert about forks
    // (we assume we don't get stuck on a fork before finishing our initial sync)
    if (IsInitialBlockDownload())
        return;

    // If our best fork is no longer within 72 blocks (+/- 12 hours if no one mines it)
    // of our head, drop it
    if (pindexBestForkTip && chainActive.Height() - pindexBestForkTip->nHeight >= 72)
        pindexBestForkTip = nullptr;

    if (pindexBestForkTip || (pindexBestInvalid && pindexBestInvalid->nChainWork > chainActive.Tip()->nChainWork + (GetBlockProof(*chainActive.Tip()) * 6)))
    {
        if (!GetfLargeWorkForkFound() && pindexBestForkBase)
        {
            std::string warning = std::string("'Warning: Large-work fork detected, forking after block ") +
                pindexBestForkBase->phashBlock->ToString() + std::string("'");
            AlertNotify(warning);
        }
        if (pindexBestForkTip && pindexBestForkBase)
        {
            LogPrintf("%s: Warning: Large valid fork found\n  forking the chain at height %d (%s)\n  lasting to height %d (%s).\nChain state database corruption likely.\n", __func__,
                   pindexBestForkBase->nHeight, pindexBestForkBase->phashBlock->ToString(),
                   pindexBestForkTip->nHeight, pindexBestForkTip->phashBlock->ToString());
            SetfLargeWorkForkFound(true);
        }
        else
        {
            LogPrintf("%s: Warning: Found invalid chain at least ~6 blocks longer than our best chain.\nChain state database corruption likely.\n", __func__);
            SetfLargeWorkInvalidChainFound(true);
        }
    }
    else
    {
        SetfLargeWorkForkFound(false);
        SetfLargeWorkInvalidChainFound(false);
    }
}

static void CheckForkWarningConditionsOnNewFork(CBlockIndex* pindexNewForkTip)
{
    AssertLockHeld(cs_main);
    // If we are on a fork that is sufficiently large, set a warning flag
    CBlockIndex* pfork = pindexNewForkTip;
    CBlockIndex* plonger = chainActive.Tip();
    while (pfork && pfork != plonger)
    {
        while (plonger && plonger->nHeight > pfork->nHeight)
            plonger = plonger->pprev;
        if (pfork == plonger)
            break;
        pfork = pfork->pprev;
    }

    // We define a condition where we should warn the user about as a fork of at least 7 blocks
    // with a tip within 72 blocks (+/- 12 hours if no one mines it) of ours
    // We use 7 blocks rather arbitrarily as it represents just under 10% of sustained network
    // hash rate operating on the fork.
    // or a chain that is entirely longer than ours and invalid (note that this should be detected by both)
    // We define it this way because it allows us to only store the highest fork tip (+ base) which meets
    // the 7-block condition and from this always have the most-likely-to-cause-warning fork
    if (pfork && (!pindexBestForkTip || pindexNewForkTip->nHeight > pindexBestForkTip->nHeight) &&
            pindexNewForkTip->nChainWork - pfork->nChainWork > (GetBlockProof(*pfork) * 7) &&
            chainActive.Height() - pindexNewForkTip->nHeight < 72)
    {
        pindexBestForkTip = pindexNewForkTip;
        pindexBestForkBase = pfork;
    }

    CheckForkWarningConditions();
}

void static InvalidChainFound(CBlockIndex* pindexNew)
{
    if (!pindexBestInvalid || pindexNew->nChainWork > pindexBestInvalid->nChainWork)
        pindexBestInvalid = pindexNew;

    LogPrintf("%s: invalid block=%s  height=%d  log2_work=%.8g  date=%s\n", __func__,
      pindexNew->GetBlockHash().ToString(), pindexNew->nHeight,
      log(pindexNew->nChainWork.getdouble())/log(2.0), DateTimeStrFormat("%Y-%m-%d %H:%M:%S",
      pindexNew->GetBlockTime()));
    CBlockIndex *tip = chainActive.Tip();
    assert (tip);
    LogPrintf("%s:  current best=%s  height=%d  log2_work=%.8g  date=%s\n", __func__,
      tip->GetBlockHash().ToString(), chainActive.Height(), log(tip->nChainWork.getdouble())/log(2.0),
      DateTimeStrFormat("%Y-%m-%d %H:%M:%S", tip->GetBlockTime()));
    CheckForkWarningConditions();
}

void CChainState::InvalidBlockFound(CBlockIndex *pindex, const CValidationState &state) {
    if (!state.CorruptionPossible()) {
        pindex->nStatus |= BLOCK_FAILED_VALID;
        g_failed_blocks.insert(pindex);
        setDirtyBlockIndex.insert(pindex);
        setBlockIndexCandidates.erase(pindex);
        InvalidChainFound(pindex);
    }
}

void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, CTxUndo &txundo, int nHeight)
{
    // mark inputs spent
    if (!tx.IsCoinBase()) {
        txundo.vprevout.reserve(tx.vin.size());
        for (const CTxIn &txin : tx.vin) {
            if (tx.IsPegsImport() && txin.prevout.n==10e8) continue;
            txundo.vprevout.emplace_back();
            bool is_spent = inputs.SpendCoin(txin.prevout, &txundo.vprevout.back());
            assert(is_spent);
        }
    }
    // add outputs
    AddCoins(inputs, tx, nHeight);

    // Unorthodox state
    if (tx.IsCoinImport() || tx.IsPegsImport()) {
        // add a tombstone for the burnTx
        AddImportTombstone(tx, inputs, nHeight);
    }
}

void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, int nHeight)
{
    CTxUndo txundo;
    UpdateCoins(tx, inputs, txundo, nHeight);
}

bool CScriptCheck::operator()() {
    const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
    const CScriptWitness *witness = &ptxTo->vin[nIn].scriptWitness;

    ServerTransactionSignatureChecker checker(ptxTo, nIn, m_tx_out.nValue, cacheStore, *txdata);
    checker.bRunHeavyCCEval = nFlags & SCRIPT_VERIFY_HEAVY_CCEVAL;
    checker.blockTxns = connectingBlockTxns;
    return VerifyScript(scriptSig, m_tx_out.scriptPubKey, witness, nFlags, checker, &error);
}

int GetSpendHeight(const CCoinsViewCache& inputs)
{
    LOCK(cs_main);
    CBlockIndex* pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
    return pindexPrev->nHeight + 1;
}


static CuckooCache::cache<uint256, SignatureCacheHasher> scriptExecutionCache;
static uint256 scriptExecutionCacheNonce(GetRandHash());

void InitScriptExecutionCache() {
    // nMaxCacheSize is unsigned. If -maxsigcachesize is set to zero,
    // setup_bytes creates the minimum possible cache (2 elements).
    size_t nMaxCacheSize = std::min(std::max((int64_t)0, gArgs.GetArg("-maxsigcachesize", DEFAULT_MAX_SIG_CACHE_SIZE) / 2), MAX_MAX_SIG_CACHE_SIZE) * ((size_t) 1 << 20);
    size_t nElems = scriptExecutionCache.setup_bytes(nMaxCacheSize);
    LogPrintf("Using %zu MiB out of %zu/2 requested for script execution cache, able to store %zu elements\n",
            (nElems*sizeof(uint256)) >>20, (nMaxCacheSize*2)>>20, nElems);
}

/**
 * Check whether all inputs of this transaction are valid (no double spends, scripts & sigs, amounts)
 * This does not modify the UTXO set.
 *
 * If pvChecks is not nullptr, script checks are pushed onto it instead of being performed inline. Any
 * script checks which are not necessary (eg due to script execution cache hits) are, obviously,
 * not pushed onto pvChecks/run.
 *
 * Setting cacheSigStore/cacheFullScriptStore to false will remove elements from the corresponding cache
 * which are matched. This is useful for checking blocks where we will likely never need the cache
 * entry again.
 *
 * Non-static (and re-declared) in src/test/txvalidationcache_tests.cpp
 */
bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheSigStore, bool cacheFullScriptStore, PrecomputedTransactionData& txdata, BlockTxnsPtr _connectingBlockTxns, std::vector<CScriptCheck> *pvChecks)
{
    if (!tx.IsCoinBase())
    {
        if (pvChecks)
            pvChecks->reserve(tx.vin.size());

        // The first loop above does all the inexpensive checks.
        // Only if ALL inputs pass do we perform expensive ECDSA signature checks.
        // Helps prevent CPU exhaustion attacks.

        // Skip script verification when connecting blocks under the
        // assumevalid block. Assuming the assumevalid block is valid this
        // is safe because block merkle hashes are still computed and checked,
        // Of course, if an assumed valid block is invalid due to false scriptSigs
        // this optimization would allow an invalid chain to be accepted.
        if (fScriptChecks) {
            // First check if script executions have been cached with the same
            // flags. Note that this assumes that the inputs provided are
            // correct (ie that the transaction hash which is in tx's prevouts
            // properly commits to the scriptPubKey in the inputs view of that
            // transaction).
            uint256 hashCacheEntry;
            // We only use the first 19 bytes of nonce to avoid a second SHA
            // round - giving us 19 + 32 + 4 = 55 bytes (+ 8 + 1 = 64)
            static_assert(55 - sizeof(flags) - 32 >= 128/8, "Want at least 128 bits of nonce for script execution cache");
            CSHA256().Write(scriptExecutionCacheNonce.begin(), 55 - sizeof(flags) - 32).Write(tx.GetWitnessHash().begin(), 32).Write((unsigned char*)&flags, sizeof(flags)).Finalize(hashCacheEntry.begin());
            AssertLockHeld(cs_main); //TODO: Remove this requirement by making CuckooCache not require external locks
            if (scriptExecutionCache.contains(hashCacheEntry, !cacheFullScriptStore)) {
                return true;
            }

            for (unsigned int i = 0; i < tx.vin.size(); i++) {
                const COutPoint &prevout = tx.vin[i].prevout;
                const Coin& coin = inputs.AccessCoin(prevout);
                assert(!coin.IsSpent());

                // We very carefully only pass in things to CScriptCheck which
                // are clearly committed to by tx' witness hash. This provides
                // a sanity check that our caching is not introducing consensus
                // failures through additional data in, eg, the coins being
                // spent being checked as a part of CScriptCheck.

                // Verify signature
                CScriptCheck check(coin.out, tx, i, flags, cacheSigStore, &txdata, _connectingBlockTxns);
                if (pvChecks) {
                    pvChecks->push_back(CScriptCheck());
                    check.swap(pvChecks->back());
                } else if (!check()) {
                    if (flags & STANDARD_NOT_MANDATORY_VERIFY_FLAGS) {
                        // Check whether the failure was caused by a
                        // non-mandatory script verification check, such as
                        // non-standard DER encodings or non-null dummy
                        // arguments; if so, don't trigger DoS protection to
                        // avoid splitting the network between upgraded and
                        // non-upgraded nodes.
                        CScriptCheck check2(coin.out, tx, i,
                                flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheSigStore, &txdata, _connectingBlockTxns);
                        if (check2())
                            return state.Invalid(false, REJECT_NONSTANDARD, strprintf("non-mandatory-script-verify-flag (%s)", ScriptErrorString(check.GetScriptError())));
                    }
                    // Failures of other flags indicate a transaction that is
                    // invalid in new blocks, e.g. an invalid P2SH. We DoS ban
                    // such nodes as they are not following the protocol. That
                    // said during an upgrade careful thought should be taken
                    // as to the correct behavior - we may want to continue
                    // peering with non-upgraded nodes even after soft-fork
                    // super-majority signaling has occurred.
                    return state.DoS(100,false, REJECT_INVALID, strprintf("mandatory-script-verify-flag-failed (%s)", ScriptErrorString(check.GetScriptError())));
                }
            }

            if (cacheFullScriptStore && !pvChecks) {
                // We executed all of the provided scripts, and were told to
                // cache the result. Do so now.
                scriptExecutionCache.insert(hashCacheEntry);
            }
        }
    }

    return true;
}

namespace {

bool UndoWriteToDisk(const CBlockUndo& blockundo, CDiskBlockPos& pos, const uint256& hashBlock, const CMessageHeader::MessageStartChars& messageStart)
{
    // Open history file to append
    CAutoFile fileout(OpenUndoFile(pos), SER_DISK, CLIENT_VERSION);
    if (fileout.IsNull())
        return error("%s: OpenUndoFile failed", __func__);

    // Write index header
    unsigned int nSize = GetSerializeSize(fileout, blockundo);
    fileout << FLATDATA(messageStart) << nSize;

    // Write undo data
    long fileOutPos = ftell(fileout.Get());
    if (fileOutPos < 0)
        return error("%s: ftell failed", __func__);
    pos.nPos = (unsigned int)fileOutPos;
    fileout << blockundo;

    // calculate & write checksum
    CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
    hasher << hashBlock;
    hasher << blockundo;
    fileout << hasher.GetHash();

    return true;
}

static bool UndoReadFromDisk(CBlockUndo& blockundo, const CBlockIndex *pindex)
{
    CDiskBlockPos pos = pindex->GetUndoPos();
    if (pos.IsNull()) {
        return error("%s: no undo data available", __func__);
    }

    // Open history file to read
    CAutoFile filein(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
    if (filein.IsNull())
        return error("%s: OpenUndoFile failed", __func__);

    // Read block
    uint256 hashChecksum;
    CHashVerifier<CAutoFile> verifier(&filein); // We need a CHashVerifier as reserializing may lose data
    try {
        verifier << pindex->pprev->GetBlockHash();
        verifier >> blockundo;
        filein >> hashChecksum;
    }
    catch (const std::exception& e) {
        return error("%s: Deserialize or I/O error - %s", __func__, e.what());
    }

    // Verify checksum
    if (hashChecksum != verifier.GetHash())
        return error("%s: Checksum mismatch", __func__);

    return true;
}

/** Abort with a message */
bool AbortNode(const std::string& strMessage, const std::string& userMessage="")
{
    SetMiscWarning(strMessage);
    LogPrintf("*** %s\n", strMessage);
    uiInterface.ThreadSafeMessageBox(
        userMessage.empty() ? _("Error: A fatal internal error occurred, see debug.log for details") : userMessage,
        "", CClientUIInterface::MSG_ERROR);
    StartShutdown();
    return false;
}

bool AbortNode(CValidationState& state, const std::string& strMessage, const std::string& userMessage="")
{
    AbortNode(strMessage, userMessage);
    return state.Error(strMessage);
}

} // namespace

/**
 * Restore the UTXO in a Coin at a given COutPoint
 * @param undo The Coin to be restored.
 * @param view The coins view to which to apply the changes.
 * @param out The out point that corresponds to the tx input.
 * @return A DisconnectResult as an int
 */
int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out)
{
    bool fClean = true;

    if (view.HaveCoin(out)) fClean = false; // overwriting transaction output

    if (undo.nHeight == 0) {
        // Missing undo metadata (height and coinbase). Older versions included this
        // information only in undo records for the last spend of a transactions'
        // outputs. This implies that it must be present for some other output of the same tx.
        const Coin& alternate = AccessByTxid(view, out.hash);
        if (!alternate.IsSpent()) {
            undo.nHeight = alternate.nHeight;
            undo.fCoinBase = alternate.fCoinBase;
        } else {
            return DISCONNECT_FAILED; // adding output for transaction without known metadata
        }
    }
    // The potential_overwrite parameter to AddCoin is only allowed to be false if we know for
    // sure that the coin did not already exist in the cache. As we have queried for that above
    // using HaveCoin, we don't need to guess. When fClean is false, a coin already existed and
    // it is an overwrite.
    view.AddCoin(out, std::move(undo), !fClean);

    return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN;
}

int8_t GetAddressType(const CScript &scriptPubKey, CTxDestination &vDest, txnouttype &txType, std::vector<std::vector<unsigned char>> &vSols)
{
    int8_t keyType = 0;
    // some non-standard types, like time lock coinbases, don't solve, but do extract
    if ( (Solver(scriptPubKey, txType, vSols) || ExtractDestination(scriptPubKey, vDest)) )
    {
//It's impossible that vDest found without corresponding vSols with GetKeyType is not null
//        if (vDest.which())
//        {
            // if we failed to solve, and got a vDest, assume P2PKH or P2PK address returned
//            CKeyID kid;
//            if (CBitcoinAddress(vDest).GetKeyID(kid))
//            {
//                vSols.push_back(std::vector<unsigned char>(kid.begin(), kid.end()));
//            }
//        }

         keyType = GetKeyType(txType);
    }
    return keyType;
}

/** Undo the effects of this block (with given index) on the UTXO set represented by coins.
 *  When FAILED is returned, view is left in an indeterminate state. */
DisconnectResult CChainState::DisconnectBlock(const CBlock& block, const CBlockIndex* pindex, CCoinsViewCache& view, bool fJustCheck)
{
    bool fClean = true;

    CBlockUndo blockUndo;
    if (!UndoReadFromDisk(blockUndo, pindex)) {
        error("DisconnectBlock(): failure reading undo data");
        return DISCONNECT_FAILED;
    }

    if (blockUndo.vtxundo.size() + 1 != block.vtx.size()) {
        error("DisconnectBlock(): block and undo data inconsistent");
        return DISCONNECT_FAILED;
    }
    std::vector<std::pair<CAddressIndexKey, CAmount> > addressIndex;
    std::vector<std::pair<CAddressUnspentKey, CAddressUnspentValue> > addressUnspentIndex;
    std::vector<std::pair<CSpentIndexKey, CSpentIndexValue> > spentIndex;

    // undo transactions in reverse order
    for (int i = block.vtx.size() - 1; i >= 0; i--) {
        const CTransaction &tx = *(block.vtx[i]);
        uint256 hash = tx.GetHash();

        if (fAddressIndex) {

            for (unsigned int k = tx.vout.size(); k-- > 0;) {
                const CTxOut &out = tx.vout[k];

                std::vector<std::vector<unsigned char>> vSols;
                CTxDestination vDest;
                txnouttype txType = TX_PUBKEYHASH;
                int keyType = GetAddressType(out.scriptPubKey, vDest, txType, vSols);
                if ( keyType != 0 )
                {
                    for (auto addr : vSols)
                    {
                        uint160 addrHash = addr.size() == 20 ? uint160(addr) : Hash160(addr);
                        addressIndex.push_back(std::make_pair(CAddressIndexKey(keyType, addrHash, pindex->GetHeight(), i, hash, k, false), out.nValue));
                        addressUnspentIndex.push_back(std::make_pair(CAddressUnspentKey(keyType, addrHash, hash, k), CAddressUnspentValue()));
                    }
                }
            }
        }

        bool is_coinbase = tx.IsCoinBase();

        // Check that all outputs are available and match the outputs in the block itself
        // exactly.
        for (size_t o = 0; o < tx.vout.size(); o++) {
            if (!tx.vout[o].scriptPubKey.IsUnspendable()) {
                COutPoint out(hash, o);
                Coin coin;
                bool is_spent = view.SpendCoin(out, &coin);
                if (!is_spent || tx.vout[o] != coin.out || pindex->nHeight != coin.nHeight || is_coinbase != coin.fCoinBase) {
                    /* This may be due to a historic bug.  For them, some names
                       are marked immediately as unspendable.  They fail this check
                       when undoing, thus ignore them here.  */
                    CChainParams::BugType type;
                    if (!Params ().IsHistoricBug (tx.GetHash (), pindex->nHeight, type) || type != CChainParams::BUG_FULLY_IGNORE) {
                        fClean = false; // transaction output mismatch
                    }
                }
            }
        }

        // restore inputs
        if (i > 0) { // not coinbases
            CTxUndo &txundo = blockUndo.vtxundo[i-1];
            if (tx.IsPegsImport()) txundo.vprevout.insert(txundo.vprevout.begin(),Coin());
            if (txundo.vprevout.size() != tx.vin.size()) {
                error("DisconnectBlock(): transaction and undo data inconsistent");
                return DISCONNECT_FAILED;
            }
            for (unsigned int j = tx.vin.size(); j-- > 0;) {
                if (tx.IsPegsImport() && j==0)  continue;
                const COutPoint &out = tx.vin[j].prevout;
                const Coin &undo = txundo.vprevout[j];
                int res = ApplyTxInUndo(std::move(txundo.vprevout[j]), view, out);
                if (res == DISCONNECT_FAILED) return DISCONNECT_FAILED;
                fClean = fClean && res != DISCONNECT_UNCLEAN;

                const CTxIn input = tx.vin[j];

                if (fSpentIndex) {
                    // undo and delete the spent index
                    spentIndex.push_back(std::make_pair(CSpentIndexKey(input.prevout.hash, input.prevout.n), CSpentIndexValue()));
                }

                if (fAddressIndex) {
                    const CTxOut &prevout = view.GetOutputFor(tx.vin[j]);

                    std::vector<std::vector<unsigned char>> vSols;
                    CTxDestination vDest;
                    txnouttype txType = TX_PUBKEYHASH;
                    int keyType = GetAddressType(prevout.scriptPubKey, vDest, txType, vSols);
                    if ( keyType != 0 )
                    {
                        for (auto addr : vSols)
                        {
                            uint160 addrHash = addr.size() == 20 ? uint160(addr) : Hash160(addr);
                            // undo spending activity
                            addressIndex.push_back(std::make_pair(CAddressIndexKey(keyType, addrHash, pindex->GetHeight(), i, hash, j, true), prevout.nValue * -1));

                            // restore unspent index
                            addressUnspentIndex.push_back(std::make_pair(CAddressUnspentKey(keyType, addrHash, input.prevout.hash, input.prevout.n), CAddressUnspentValue(prevout.nValue, prevout.scriptPubKey, undo.nHeight)));
                        }
                    }
                }
            }
            // At this point, all of txundo.vprevout should have been moved out.
        }
        else if (tx.IsCoinImport() || tx.IsPegsImport())
        {
            RemoveImportTombstone(tx, view);
        }
    }

    komodo_disconnect((CBlockIndex *)pindex,(CBlock *)&block);

    // move best block pointer to prevout block
    view.SetBestBlock(pindex->pprev->GetBlockHash());

    // if fJustCheck passed, this is a call from CVerifyDB::VerifyDB (check level 3) - we shouldn't
    // erase indexes, otherwise we will need reindex
    if (fJustCheck) {
        return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN;
    }

    if (fAddressIndex) {
        if (!pblocktree->EraseAddressIndex(addressIndex)) {
            AbortNode("Failed to delete address index");
            return DISCONNECT_FAILED;
        }
        if (!pblocktree->UpdateAddressUnspentIndex(addressUnspentIndex)) {
            AbortNode("Failed to write address unspent index");
            return DISCONNECT_FAILED;
        }
    }

    return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN;
}

void static FlushBlockFile(bool fFinalize = false)
{
    LOCK(cs_LastBlockFile);

    CDiskBlockPos posOld(nLastBlockFile, 0);

    FILE *fileOld = OpenBlockFile(posOld);
    if (fileOld) {
        if (fFinalize)
            TruncateFile(fileOld, vinfoBlockFile[nLastBlockFile].nSize);
        FileCommit(fileOld);
        fclose(fileOld);
    }

    fileOld = OpenUndoFile(posOld);
    if (fileOld) {
        if (fFinalize)
            TruncateFile(fileOld, vinfoBlockFile[nLastBlockFile].nUndoSize);
        FileCommit(fileOld);
        fclose(fileOld);
    }
}

static bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos, unsigned int nAddSize);

static bool WriteUndoDataForBlock(const CBlockUndo& blockundo, CValidationState& state, CBlockIndex* pindex, const CChainParams& chainparams)
{
    // Write undo information to disk
    if (pindex->GetUndoPos().IsNull()) {
        CDiskBlockPos _pos;
        if (!FindUndoPos(state, pindex->nFile, _pos, ::GetSerializeSize(blockundo, SER_DISK, 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");

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

    return true;
}

static bool WriteTxIndexDataForBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex)
{
    if (!fTxIndex) return true;

    CDiskTxPos pos(pindex->GetBlockPos(), GetSizeOfCompactSize(block.vtx.size()));
    std::vector<std::pair<uint256, CDiskTxPos> > vPos;
    vPos.reserve(block.vtx.size());
    for (const CTransactionRef& tx : block.vtx)
    {
        vPos.push_back(std::make_pair(tx->GetHash(), pos));
        pos.nTxOffset += ::GetSerializeSize(*tx, SER_DISK, CLIENT_VERSION);
    }

    if (!pblocktree->WriteTxIndex(vPos)) {
        return AbortNode(state, "Failed to write transaction index");
    }

    return true;
}

static CCheckQueue<CScriptCheck> scriptcheckqueue(128);

void ThreadScriptCheck() {
    RenameThread("bitcoin-scriptch");
    scriptcheckqueue.Thread();
}

// Protected by cs_main
VersionBitsCache versionbitscache;

int32_t ComputeBlockVersion(const CBlockIndex* pindexPrev, const Consensus::Params& params)
{
    LOCK(cs_main);
    int32_t nVersion = VERSIONBITS_TOP_BITS;

    for (int i = 0; i < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; i++) {
        ThresholdState state = VersionBitsState(pindexPrev, params, static_cast<Consensus::DeploymentPos>(i), versionbitscache);
        if (state == THRESHOLD_LOCKED_IN || state == THRESHOLD_STARTED) {
            nVersion |= VersionBitsMask(params, static_cast<Consensus::DeploymentPos>(i));
        }
    }

    return nVersion;
}

/**
 * Threshold condition checker that triggers when unknown versionbits are seen on the network.
 */
class WarningBitsConditionChecker : public AbstractThresholdConditionChecker
{
private:
    int bit;

public:
    explicit WarningBitsConditionChecker(int bitIn) : bit(bitIn) {}

    int64_t BeginTime(const Consensus::Params& params) const override { return 0; }
    int64_t EndTime(const Consensus::Params& params) const override { return std::numeric_limits<int64_t>::max(); }
    int Period(const Consensus::Params& params) const override { return params.nMinerConfirmationWindow; }
    int Threshold(const Consensus::Params& params) const override { return params.nRuleChangeActivationThreshold; }

    bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const override
    {
        return ((pindex->nVersion & VERSIONBITS_TOP_MASK) == VERSIONBITS_TOP_BITS) &&
               ((pindex->nVersion >> bit) & 1) != 0 &&
               ((ComputeBlockVersion(pindex->pprev, params) >> bit) & 1) == 0;
    }
};

// Protected by cs_main
static ThresholdConditionCache warningcache[VERSIONBITS_NUM_BITS];

static unsigned int GetBlockScriptFlags(const CBlockIndex* pindex, const Consensus::Params& consensusparams) {
    AssertLockHeld(cs_main);

    unsigned int flags = SCRIPT_VERIFY_NONE;

    // Start enforcing P2SH (BIP16)
    if (pindex->nHeight >= consensusparams.BIP16Height) {
        flags |= SCRIPT_VERIFY_P2SH;
    }

    // Start enforcing the DERSIG (BIP66) rule
    if (pindex->nHeight >= consensusparams.BIP66Height) {
        flags |= SCRIPT_VERIFY_DERSIG;
    }

    // Start enforcing CHECKLOCKTIMEVERIFY (BIP65) rule
    if (pindex->nHeight >= consensusparams.BIP65Height) {
        flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
    }

    // Start enforcing BIP68 (sequence locks) and BIP112 (CHECKSEQUENCEVERIFY) using versionbits logic.
    if (VersionBitsState(pindex->pprev, consensusparams, Consensus::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
        flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
    }

    // Start enforcing WITNESS rules using versionbits logic.
    if (IsWitnessEnabled(pindex->pprev, consensusparams)) {
        flags |= SCRIPT_VERIFY_WITNESS;
        flags |= SCRIPT_VERIFY_NULLDUMMY;
    }

    if (IsCryptoConditionsEnabled())
        flags |= SCRIPT_VERIFY_HEAVY_CCEVAL;

    return flags;
}



static int64_t nTimeCheck = 0;
static int64_t nTimeForks = 0;
static int64_t nTimeVerify = 0;
static int64_t nTimeConnect = 0;
static int64_t nTimeIndex = 0;
static int64_t nTimeCallbacks = 0;
static int64_t nTimeTotal = 0;
static int64_t nBlocksTotal = 0;


// #pragma GCC push_options
// #pragma GCC optimize ("O0")

/** Apply the effects of this block (with given index) on the UTXO set represented by coins.
 *  Validity checks that depend on the UTXO set are also done; ConnectBlock()
 *  can fail if those validity checks fail (among other reasons). */
bool CChainState::ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex,
                  CCoinsViewCache& view,
                  const CChainParams& chainparams, bool fJustCheck)
{
    AssertLockHeld(cs_main);
    assert(pindex);
    // pindex->phashBlock can be null if called by CreateNewBlock/TestBlockValidity
    assert((pindex->phashBlock == nullptr) ||
           (*pindex->phashBlock == block.GetHash()));
    int64_t nTimeStart = GetTimeMicros();

    // Check it again in case a previous version let a bad block in
    // NOTE: We don't currently (re-)invoke ContextualCheckBlock() or
    // ContextualCheckBlockHeader() here. This means that if we add a new
    // consensus rule that is enforced in one of those two functions, then we
    // may have let in a block that violates the rule prior to updating the
    // software, and we would NOT be enforcing the rule here. Fully solving
    // upgrade from one software version to the next after a consensus rule
    // change is potentially tricky and issue-specific (see RewindBlockIndex()
    // for one general approach that was used for BIP 141 deployment).
    // Also, currently the rule against blocks more than 2 hours in the future
    // is enforced in ContextualCheckBlockHeader(); we wouldn't want to
    // re-enforce that rule here (at least until we make it impossible for
    // GetAdjustedTime() to go backward).
    if (!CheckBlock(block, state, chainparams.GetConsensus(), !fJustCheck, !fJustCheck))
        return error("%s: Consensus::CheckBlock: %s", __func__, FormatStateMessage(state));

    // verify that the view's current state corresponds to the previous block
    uint256 hashPrevBlock = pindex->pprev == nullptr ? uint256() : pindex->pprev->GetBlockHash();
    assert(hashPrevBlock == view.GetBestBlock());

    // Special case for the genesis block, skipping connection of its transactions
    // (its coinbase is unspendable)
    if (block.GetHash() == chainparams.GetConsensus().hashGenesisBlock) {
        if (!fJustCheck)
            view.SetBestBlock(pindex->GetBlockHash());
        return true;
    }

    nBlocksTotal++;

    bool fScriptChecks = true;
    if (!hashAssumeValid.IsNull()) {
        // We've been configured with the hash of a block which has been externally verified to have a valid history.
        // A suitable default value is included with the software and updated from time to time.  Because validity
        //  relative to a piece of software is an objective fact these defaults can be easily reviewed.
        // This setting doesn't force the selection of any particular chain but makes validating some faster by
        //  effectively caching the result of part of the verification.
        BlockMap::const_iterator  it = mapBlockIndex.find(hashAssumeValid);
        if (it != mapBlockIndex.end()) {
            if (it->second->GetAncestor(pindex->nHeight) == pindex &&
                pindexBestHeader->GetAncestor(pindex->nHeight) == pindex &&
                pindexBestHeader->nChainWork >= nMinimumChainWork) {
                // This block is a member of the assumed verified chain and an ancestor of the best header.
                // The equivalent time check discourages hash power from extorting the network via DOS attack
                //  into accepting an invalid block through telling users they must manually set assumevalid.
                //  Requiring a software change or burying the invalid block, regardless of the setting, makes
                //  it hard to hide the implication of the demand.  This also avoids having release candidates
                //  that are hardly doing any signature verification at all in testing without having to
                //  artificially set the default assumed verified block further back.
                // The test against nMinimumChainWork prevents the skipping when denied access to any chain at
                //  least as good as the expected chain.
                fScriptChecks = (GetBlockProofEquivalentTime(*pindexBestHeader, *pindex, *pindexBestHeader, chainparams.GetConsensus()) <= 60 * 60 * 24 * 7 * 2);
            }
        }
    }

    int64_t nTime1 = GetTimeMicros(); nTimeCheck += nTime1 - nTimeStart;
    LogPrint(BCLog::BENCH, "    - Sanity checks: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime1 - nTimeStart), nTimeCheck * MICRO, nTimeCheck * MILLI / nBlocksTotal);

    // Do not allow blocks that contain transactions which 'overwrite' older transactions,
    // unless those are already completely spent.
    // If such overwrites are allowed, coinbases and transactions depending upon those
    // can be duplicated to remove the ability to spend the first instance -- even after
    // being sent to another address.
    // See BIP30 and http://r6.ca/blog/20120206T005236Z.html for more information.
    // This logic is not necessary for memory pool transactions, as AcceptToMemoryPool
    // already refuses previously-known transaction ids entirely.
    // FIXME: Enable strict check after appropriate fork.
    bool fEnforceBIP30 = (!pindex->phashBlock) || // Enforce on CreateNewBlock invocations which don't have a hash.
                          !(true);

    // Once BIP34 activated it was not possible to create new duplicate coinbases and thus other than starting
    // with the 2 existing duplicate coinbase pairs, not possible to create overwriting txs.  But by the
    // time BIP34 activated, in each of the existing pairs the duplicate coinbase had overwritten the first
    // before the first had been spent.  Since those coinbases are sufficiently buried its no longer possible to create further
    // duplicate transactions descending from the known pairs either.
    // If we're on the known chain at height greater than where BIP34 activated, we can save the db accesses needed for the BIP30 check.
    assert(pindex->pprev);
    CBlockIndex *pindexBIP34height = pindex->pprev->GetAncestor(chainparams.GetConsensus().BIP34Height);
    //Only continue to enforce if we're below BIP34 activation height or the block hash at that height doesn't correspond.
    fEnforceBIP30 = fEnforceBIP30 && (!pindexBIP34height || !(pindexBIP34height->GetBlockHash() == chainparams.GetConsensus().BIP34Hash));

    if (fEnforceBIP30) {
        for (const auto& tx : block.vtx) {
            for (size_t o = 0; o < tx->vout.size(); o++) {
                if (view.HaveCoin(COutPoint(tx->GetHash(), o))) {
                    return state.DoS(100, error("ConnectBlock(): tried to overwrite transaction"),
                                     REJECT_INVALID, "bad-txns-BIP30");
                }
            }
        }
    }

    // Start enforcing BIP68 (sequence locks) and BIP112 (CHECKSEQUENCEVERIFY) using versionbits logic.
    int nLockTimeFlags = 0;
    if (VersionBitsState(pindex->pprev, chainparams.GetConsensus(), Consensus::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
        nLockTimeFlags |= LOCKTIME_VERIFY_SEQUENCE;
    }

    // Get the script flags for this block
    unsigned int flags = GetBlockScriptFlags(pindex, chainparams.GetConsensus());

    int64_t nTime2 = GetTimeMicros(); nTimeForks += nTime2 - nTime1;
    LogPrint(BCLog::BENCH, "    - Fork checks: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime2 - nTime1), nTimeForks * MICRO, nTimeForks * MILLI / nBlocksTotal);

    CBlockUndo blockundo;

    if ( scriptcheckqueue.IsIdle() == 0 )
    {
        LogPrintf("scriptcheckqueue isnt idle\n");
#ifdef WIN32
        boost::this_thread::sleep(boost::posix_time::milliseconds(1000));
#else
        sleep(1);
#endif
    }

    CCheckQueueControl<CScriptCheck> control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : nullptr);

    std::vector<int> prevheights;
    CAmount nFees = 0;
    int nInputs = 0;
    int64_t nSigOpsCost = 0;
    blockundo.vtxundo.reserve(block.vtx.size() - 1);
    std::vector<std::pair<CAddressIndexKey, CAmount> > addressIndex;
    std::vector<std::pair<CAddressUnspentKey, CAddressUnspentValue> > addressUnspentIndex;
    std::vector<std::pair<CSpentIndexKey, CSpentIndexValue> > spentIndex;
    std::vector<PrecomputedTransactionData> txdata;

    // store current block txns to allow to refer them from validation code
    MapBlockTxns *pBlockTxns = new MapBlockTxns();
    for (auto const &ptx : block.vtx)  {
        if (ptx->IsCoinBase())
            continue;
        (*pBlockTxns)[ptx->GetHash()] = *ptx;
    }
    BlockTxnsPtr connectingBlockTxns(pBlockTxns); // use auto deleting object-pointer

    txdata.reserve(block.vtx.size()); // Required so that pointers to individual PrecomputedTransactionData don't get invalidated
    for (unsigned int i = 0; i < block.vtx.size(); i++)
    {
        const CTransaction &tx = *(block.vtx[i]);
        const uint256 txhash = tx.GetHash();

        nInputs += tx.vin.size();

        if (!tx.IsCoinBase())
        {
            CAmount txfee = 0;
            if (!Consensus::CheckTxInputs(tx, state, view, pindex->nHeight, txfee)) {
                return error("%s: Consensus::CheckTxInputs: %s, %s", __func__, tx.GetHash().ToString(), FormatStateMessage(state));
            }
            nFees += txfee;
            if (!MoneyRange(nFees)) {
                return state.DoS(100, error("%s: accumulated fee in the block out of range.", __func__),
                                 REJECT_INVALID, "bad-txns-accumulated-fee-outofrange");
            }

            // Check that transaction is BIP68 final
            // BIP68 lock checks (as opposed to nLockTime checks) must
            // be in ConnectBlock because they require the UTXO set
            prevheights.resize(tx.vin.size());
            for (size_t j = 0; j < tx.vin.size(); j++) {
                prevheights[j] = view.AccessCoin(tx.vin[j].prevout).nHeight;
            }

            if (!SequenceLocks(tx, nLockTimeFlags, &prevheights, *pindex)) {
                return state.DoS(100, error("%s: contains a non-BIP68-final transaction", __func__),
                                 REJECT_INVALID, "bad-txns-nonfinal");
            }

            if (fAddressIndex || fSpentIndex)
            {
                for (size_t j = 0; j < tx.vin.size(); j++)
                {
                    if (tx.IsPegsImport() && j==0) continue;
                    const CTxIn input = tx.vin[j];
                    const CTxOut &prevout = view.GetOutputFor(tx.vin[j]);

                    std::vector<std::vector<unsigned char>> vSols;
                    CTxDestination vDest;
                    txnouttype txType = TX_PUBKEYHASH;
                    uint160 addrHash;
                    int keyType = GetAddressType(prevout.scriptPubKey, vDest, txType, vSols);
                    if ( keyType != 0 )
                    {
                        for (auto addr : vSols)
                        {
                            addrHash = addr.size() == 20 ? uint160(addr) : Hash160(addr);
                            // record spending activity
                            addressIndex.push_back(std::make_pair(CAddressIndexKey(keyType, addrHash, pindex->GetHeight(), i, txhash, j, true), prevout.nValue * -1));

                            // remove address from unspent index
                            addressUnspentIndex.push_back(std::make_pair(CAddressUnspentKey(keyType, addrHash, input.prevout.hash, input.prevout.n), CAddressUnspentValue()));
                        }

                        if (fSpentIndex) {
                            // add the spent index to determine the txid and input that spent an output
                            // and to find the amount and address from an input
                            spentIndex.push_back(std::make_pair(CSpentIndexKey(input.prevout.hash, input.prevout.n), CSpentIndexValue(txhash, j, pindex->GetHeight(), prevout.nValue, keyType, addrHash)));
                        }
                    }
                }
            }
        }

        // GetTransactionSigOpCost counts 3 types of sigops:
        // * legacy (always)
        // * p2sh (when P2SH enabled in flags and excludes coinbase)
        // * witness (when witness enabled in flags and excludes coinbase)
        nSigOpsCost += GetTransactionSigOpCost(tx, view, flags);
        if (nSigOpsCost > MAX_BLOCK_SIGOPS_COST)
            return state.DoS(100, error("ConnectBlock(): too many sigops"),
                             REJECT_INVALID, "bad-blk-sigops");

        txdata.emplace_back(tx);
        if (!tx.IsCoinBase())
        {
            std::vector<CScriptCheck> vChecks;
            bool fCacheResults = fJustCheck; /* Don't cache results if we're actually connecting blocks (still consult the cache, though) */
            if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, fCacheResults, txdata[i], connectingBlockTxns, nScriptCheckThreads ? &vChecks : nullptr))
                return error("ConnectBlock(): CheckInputs on %s failed with %s",
                    tx.GetHash().ToString(), FormatStateMessage(state));
            control.Add(vChecks);
        }

        if (fAddressIndex) {
            for (unsigned int k = 0; k < tx.vout.size(); k++) {
                const CTxOut &out = tx.vout[k];

                uint160 addrHash;

                std::vector<std::vector<unsigned char>> vSols;
                CTxDestination vDest;
                txnouttype txType = TX_PUBKEYHASH;
                int keyType = GetAddressType(out.scriptPubKey, vDest, txType, vSols);

                if ( keyType != 0 )
                {
                    for (auto addr : vSols)
                    {
                        // in case of keyType == 1 and txType == TX_PUBKEY, vSols[0] will contain pubkey itself
                        // (for compressed - 33 bytes), so, Hash160(pubkey) will give us addrHash which we want
                        // TODO: check TX_CRYPTOCONDITION, TX_WITNESS_V0_SCRIPTHASH and TX_WITNESS_V0_KEYHASH
                        // behavior

                        addrHash = addr.size() == 20 ? uint160(addr) : Hash160(addr);
                        // record receiving activity
                        addressIndex.push_back(std::make_pair(CAddressIndexKey(keyType, addrHash, pindex->GetHeight(), i, txhash, k, false), out.nValue));

                        // record unspent output
                        addressUnspentIndex.push_back(std::make_pair(CAddressUnspentKey(keyType, addrHash, txhash, k), CAddressUnspentValue(out.nValue, out.scriptPubKey, pindex->GetHeight())));
                    }
                }
            }
        }

        CTxUndo undoDummy;
        if (i > 0) {
            blockundo.vtxundo.push_back(CTxUndo());
        }
        UpdateCoins(tx, view, i == 0 ? undoDummy : blockundo.vtxundo.back(), pindex->nHeight);
        assert(pindex->nHeight != MEMPOOL_HEIGHT);
    }
    int64_t nTime3 = GetTimeMicros(); nTimeConnect += nTime3 - nTime2;
    LogPrint(BCLog::BENCH, "      - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) [%.2fs (%.2fms/blk)]\n", (unsigned)block.vtx.size(), MILLI * (nTime3 - nTime2), MILLI * (nTime3 - nTime2) / block.vtx.size(), nInputs <= 1 ? 0 : MILLI * (nTime3 - nTime2) / (nInputs-1), nTimeConnect * MICRO, nTimeConnect * MILLI / nBlocksTotal);

    // Licensed miners check
    bool fCBMinerAllowed = true;

    if (pindex->nHeight > chainparams.UseLicensedMinersAfterHeight()) {
        const std::set<CScript>& setAllowedCBScripts = chainparams.GetAllowedLicensedMinersScriptsAtHeight(pindex->nHeight);
        if (setAllowedCBScripts.size())
        {
            CScript scriptDummy = CScript() << OP_TRUE;

            if (!block.vtx.empty())
            {
                if (!(block.vtx[0]->vout.size() == 1 && block.vtx[0]->vout[0].scriptPubKey == scriptDummy)) // look at getblocktemplate (mining.cpp), allowing blocktemplate creation
                {
                    for (size_t o = 0; o < block.vtx[0]->vout.size(); o++) {
                        if (!setAllowedCBScripts.count(block.vtx[0]->vout[o].scriptPubKey))
                        {
                            fCBMinerAllowed = false; // one of cb-scripts not found in allowed
                            break;
                        }
                    }
                }
            }
        }
    }

    if (!fCBMinerAllowed) {
        CTxDestination addressInCB; std::string strAddressInCB = "< unknown >";
        if ((!block.vtx.empty()) && (block.vtx[0]->vout.size() >= 1))
        {
            if (ExtractDestination(block.vtx[0]->vout[0].scriptPubKey, addressInCB)) {
                strAddressInCB = EncodeDestination(addressInCB);
            }
        }
        return state.DoS(100, error("ConnectBlock(): %s -> not licensed miner in coinbase: %s", block.GetHash().ToString(), strAddressInCB), REJECT_INVALID, "bad-cb-miner", false, "not licensed miner in coinbase");
    }

    CAmount blockReward = nFees + GetBlockSubsidy(pindex->nHeight, chainparams.GetConsensus());
    if (block.vtx[0]->GetValueOut() > blockReward)
        return state.DoS(100,
                         error("ConnectBlock(): coinbase pays too much (actual=%d vs limit=%d)",
                               block.vtx[0]->GetValueOut(), blockReward),
                               REJECT_INVALID, "bad-cb-amount");

    if (!control.Wait())
        return state.DoS(100, error("%s: CheckQueue failed", __func__), REJECT_INVALID, "block-validation-failed");
    int64_t nTime4 = GetTimeMicros(); nTimeVerify += nTime4 - nTime2;
    LogPrint(BCLog::BENCH, "    - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs (%.2fms/blk)]\n", nInputs - 1, MILLI * (nTime4 - nTime2), nInputs <= 1 ? 0 : MILLI * (nTime4 - nTime2) / (nInputs-1), nTimeVerify * MICRO, nTimeVerify * MILLI / nBlocksTotal);

    if (fJustCheck)
        return true;

    if (!WriteUndoDataForBlock(blockundo, state, pindex, chainparams))
        return false;

    if (!pindex->IsValid(BLOCK_VALID_SCRIPTS)) {
        pindex->RaiseValidity(BLOCK_VALID_SCRIPTS);
        setDirtyBlockIndex.insert(pindex);
    }

    if (!WriteTxIndexDataForBlock(block, state, pindex))
        return false;

    assert(pindex->phashBlock);

    if (fAddressIndex) {
        if (!pblocktree->WriteAddressIndex(addressIndex)) {
            return AbortNode(state, "Failed to write address index");
        }

        if (!pblocktree->UpdateAddressUnspentIndex(addressUnspentIndex)) {
            return AbortNode(state, "Failed to write address unspent index");
        }
    }

    if (fSpentIndex)
        if (!pblocktree->UpdateSpentIndex(spentIndex))
            return AbortNode(state, "Failed to write transaction index");

    if (fTimestampIndex)
    {
        unsigned int logicalTS = pindex->nTime;
        unsigned int prevLogicalTS = 0;

        // retrieve logical timestamp of the previous block
        if (pindex->pprev)
            if (!pblocktree->ReadTimestampBlockIndex(pindex->pprev->GetBlockHash(), prevLogicalTS))
                LogPrintf("%s: Failed to read previous block's logical timestamp\n", __func__);

        if (logicalTS <= prevLogicalTS) {
            logicalTS = prevLogicalTS + 1;
            LogPrintf("%s: Previous logical timestamp is newer Actual[%d] prevLogical[%d] Logical[%d]\n", __func__, pindex->nTime, prevLogicalTS, logicalTS);
        }

        if (!pblocktree->WriteTimestampIndex(CTimestampIndexKey(logicalTS, pindex->GetBlockHash())))
            return AbortNode(state, "Failed to write timestamp index");

        if (!pblocktree->WriteTimestampBlockIndex(CTimestampBlockIndexKey(pindex->GetBlockHash()), CTimestampBlockIndexValue(logicalTS)))
            return AbortNode(state, "Failed to write blockhash index");
    }

    // add this block to the view's block chain
    view.SetBestBlock(pindex->GetBlockHash());

    int64_t nTime5 = GetTimeMicros(); nTimeIndex += nTime5 - nTime4;
    LogPrint(BCLog::BENCH, "    - Index writing: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime5 - nTime4), nTimeIndex * MICRO, nTimeIndex * MILLI / nBlocksTotal);

    int64_t nTime6 = GetTimeMicros(); nTimeCallbacks += nTime6 - nTime5;
    LogPrint(BCLog::BENCH, "    - Callbacks: %.2fms [%.2fs (%.2fms/blk)]\n", MILLI * (nTime6 - nTime5), nTimeCallbacks * MICRO, nTimeCallbacks * MILLI / nBlocksTotal);

    return true;
}

// #pragma GCC pop_options

/**
 * Update the on-disk chain state.
 * The caches and indexes are flushed depending on the mode we're called with
 * if they're too large, if it's been a while since the last write,
 * or always and in all cases if we're in prune mode and are deleting files.
 */
bool static FlushStateToDisk(const CChainParams& chainparams, CValidationState &state, FlushStateMode mode, int nManualPruneHeight) {
    int64_t nMempoolUsage = mempool.DynamicMemoryUsage();
    LOCK(cs_main);
    static int64_t nLastWrite = 0;
    static int64_t nLastFlush = 0;
    static int64_t nLastSetChain = 0;
    std::set<int> setFilesToPrune;
    bool fFlushForPrune = false;
    bool fDoFullFlush = false;
    int64_t nNow = 0;
    try {
    {
        LOCK(cs_LastBlockFile);
        if (fPruneMode && (fCheckForPruning || nManualPruneHeight > 0) && !fReindex) {
            if (nManualPruneHeight > 0) {
                FindFilesToPruneManual(setFilesToPrune, nManualPruneHeight);
            } else {
                FindFilesToPrune(setFilesToPrune, chainparams.PruneAfterHeight());
                fCheckForPruning = false;
            }
            if (!setFilesToPrune.empty()) {
                fFlushForPrune = true;
                if (!fHavePruned) {
                    pblocktree->WriteFlag("prunedblockfiles", true);
                    fHavePruned = true;
                }
            }
        }
        nNow = GetTimeMicros();
        // Avoid writing/flushing immediately after startup.
        if (nLastWrite == 0) {
            nLastWrite = nNow;
        }
        if (nLastFlush == 0) {
            nLastFlush = nNow;
        }
        if (nLastSetChain == 0) {
            nLastSetChain = nNow;
        }
        int64_t nMempoolSizeMax = gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
        int64_t cacheSize = pcoinsTip->DynamicMemoryUsage();
        int64_t nTotalSpace = nCoinCacheUsage + std::max<int64_t>(nMempoolSizeMax - nMempoolUsage, 0);
        // The cache is large and we're within 10% and 10 MiB of the limit, but we have time now (not in the middle of a block processing).
        bool fCacheLarge = mode == FLUSH_STATE_PERIODIC && cacheSize > std::max((9 * nTotalSpace) / 10, nTotalSpace - MAX_BLOCK_COINSDB_USAGE * 1024 * 1024);
        // The cache is over the limit, we have to write now.
        bool fCacheCritical = mode == FLUSH_STATE_IF_NEEDED && cacheSize > nTotalSpace;
        // It's been a while since we wrote the block index to disk. Do this frequently, so we don't need to redownload after a crash.
        bool fPeriodicWrite = mode == FLUSH_STATE_PERIODIC && nNow > nLastWrite + (int64_t)DATABASE_WRITE_INTERVAL * 1000000;
        // It's been very long since we flushed the cache. Do this infrequently, to optimize cache usage.
        bool fPeriodicFlush = mode == FLUSH_STATE_PERIODIC && nNow > nLastFlush + (int64_t)DATABASE_FLUSH_INTERVAL * 1000000;
        // Combine all conditions that result in a full cache flush.
        fDoFullFlush = (mode == FLUSH_STATE_ALWAYS) || fCacheLarge || fCacheCritical || fPeriodicFlush || fFlushForPrune;
        // Write blocks and block index to disk.
        if (fDoFullFlush || fPeriodicWrite) {
            // Depend on nMinDiskSpace to ensure we can write block index
            if (!CheckDiskSpace(0))
                return state.Error("out of disk space");
            // First make sure all block and undo data is flushed to disk.
            FlushBlockFile();
            // Then update all block file information (which may refer to block and undo files).
            {
                std::vector<std::pair<int, const CBlockFileInfo*> > vFiles;
                vFiles.reserve(setDirtyFileInfo.size());
                for (std::set<int>::iterator it = setDirtyFileInfo.begin(); it != setDirtyFileInfo.end(); ) {
                    vFiles.push_back(std::make_pair(*it, &vinfoBlockFile[*it]));
                    setDirtyFileInfo.erase(it++);
                }
                std::vector<const CBlockIndex*> vBlocks;
                vBlocks.reserve(setDirtyBlockIndex.size());
                for (std::set<CBlockIndex*>::iterator it = setDirtyBlockIndex.begin(); it != setDirtyBlockIndex.end(); ) {
                    vBlocks.push_back(*it);
                    setDirtyBlockIndex.erase(it++);
                }
                if (!pblocktree->WriteBatchSync(vFiles, nLastBlockFile, vBlocks)) {
                    return AbortNode(state, "Failed to write to block index database");
                }
            }
            // Finally remove any pruned files
            if (fFlushForPrune)
                UnlinkPrunedFiles(setFilesToPrune);
            nLastWrite = nNow;
        }
        // Flush best chain related state. This can only be done if the blocks / block index write was also done.
        if (fDoFullFlush && !pcoinsTip->GetBestBlock().IsNull()) {
            // Typical Coin structures on disk are around 48 bytes in size.
            // Pushing a new one to the database can cause it to be written
            // twice (once in the log, and once in the tables). This is already
            // an overestimation, as most will delete an existing entry or
            // overwrite one. Still, use a conservative safety factor of 2.
            if (!CheckDiskSpace(48 * 2 * 2 * pcoinsTip->GetCacheSize()))
                return state.Error("out of disk space");
            // Flush the chainstate (which may refer to block index entries).
            if (!pcoinsTip->Flush())
                return AbortNode(state, "Failed to write to coin database");
            nLastFlush = nNow;
        }
    }
    if (fDoFullFlush || ((mode == FLUSH_STATE_ALWAYS || mode == FLUSH_STATE_PERIODIC) && nNow > nLastSetChain + (int64_t)DATABASE_WRITE_INTERVAL * 1000000)) {
        // Update best block in wallet (so we can detect restored wallets).
        GetMainSignals().SetBestChain(chainActive.GetLocator());
        nLastSetChain = nNow;
    }
    } catch (const std::runtime_error& e) {
        return AbortNode(state, std::string("System error while flushing: ") + e.what());
    }
    return true;
}

void FlushStateToDisk() {
    CValidationState state;
    const CChainParams& chainparams = Params();
    FlushStateToDisk(chainparams, state, FLUSH_STATE_ALWAYS);
}

void PruneAndFlush() {
    CValidationState state;
    fCheckForPruning = true;
    const CChainParams& chainparams = Params();
    FlushStateToDisk(chainparams, state, FLUSH_STATE_NONE);
}

static void DoWarning(const std::string& strWarning)
{
    static bool fWarned = false;
    SetMiscWarning(strWarning);
    if (!fWarned) {
        AlertNotify(strWarning);
        fWarned = true;
    }
}

/** Check warning conditions and do some notifications on new chain tip set. */
void static UpdateTip(const CBlockIndex *pindexNew, const CChainParams& chainParams) {
    // New best block
    mempool.AddTransactionsUpdated(1);

    {
        WaitableLock lock(csBestBlock);
        hashBestBlock = pindexNew->GetBlockHash();
        cvBlockChange.notify_all();
    }

    std::vector<std::string> warningMessages;
    if (!IsInitialBlockDownload())
    {
        int nUpgraded = 0;
        const CBlockIndex* pindex = pindexNew;
        for (int bit = 0; bit < VERSIONBITS_NUM_BITS; bit++) {
            WarningBitsConditionChecker checker(bit);
            ThresholdState state = checker.GetStateFor(pindex, chainParams.GetConsensus(), warningcache[bit]);
            if (state == THRESHOLD_ACTIVE || state == THRESHOLD_LOCKED_IN) {
                const std::string strWarning = strprintf(_("Warning: unknown new rules activated (versionbit %i)"), bit);
                if (state == THRESHOLD_ACTIVE) {
                    DoWarning(strWarning);
                } else {
                    warningMessages.push_back(strWarning);
                }
            }
        }
        // Check the version of the last 100 blocks to see if we need to upgrade:
        for (int i = 0; i < 100 && pindex != nullptr; i++)
        {
            int32_t nExpectedVersion = ComputeBlockVersion(pindex->pprev, chainParams.GetConsensus());
            if (pindex->GetBaseVersion() > VERSIONBITS_LAST_OLD_BLOCK_VERSION && (pindex->GetBaseVersion() & ~nExpectedVersion) != 0)
                ++nUpgraded;
            pindex = pindex->pprev;
        }
        if (nUpgraded > 0)
            warningMessages.push_back(strprintf(_("%d of last 100 blocks have unexpected version"), nUpgraded));
        if (nUpgraded > 100/2)
        {
            std::string strWarning = _("Warning: Unknown block versions being mined! It's possible unknown rules are in effect");
            // notify GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
            DoWarning(strWarning);
        }
    }
    LogPrintf("%s: new best=%s height=%d version=0x%08x log2_work=%.8g tx=%lu date='%s' progress=%f cache=%.1fMiB(%utxo)", __func__,
      pindexNew->GetBlockHash().ToString(), pindexNew->nHeight, pindexNew->nVersion,
      log(pindexNew->nChainWork.getdouble())/log(2.0), (unsigned long)pindexNew->nChainTx,
      DateTimeStrFormat("%Y-%m-%d %H:%M:%S", pindexNew->GetBlockTime()),
      GuessVerificationProgress(chainParams.TxData(), pindexNew), pcoinsTip->DynamicMemoryUsage() * (1.0 / (1<<20)), pcoinsTip->GetCacheSize());
    if (!warningMessages.empty())
        LogPrintf(" warning='%s'", boost::algorithm::join(warningMessages, ", "));
    LogPrintf("\n");

}

/** Disconnect chainActive's tip.
  * After calling, the mempool will be in an inconsistent state, with
  * transactions from disconnected blocks being added to disconnectpool.  You
  * should make the mempool consistent again by calling UpdateMempoolForReorg.
  * with cs_main held.
  *
  * If disconnectpool is nullptr, then no disconnected transactions are added to
  * disconnectpool (note that the caller is responsible for mempool consistency
  * in any case).
  */
bool CChainState::DisconnectTip(CValidationState& state, const CChainParams& chainparams, DisconnectedBlockTransactions *disconnectpool)
{
    CBlockIndex *pindexDelete = chainActive.Tip();
    assert(pindexDelete);
    // Read block from disk.
    std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
    CBlock& block = *pblock;
    if (!ReadBlockFromDisk(block, pindexDelete, chainparams.GetConsensus()))
        return AbortNode(state, "Failed to read block");
    // Apply the block atomically to the chain state.
    int64_t nStart = GetTimeMicros();
    {
        CCoinsViewCache view(pcoinsTip.get());
        assert(view.GetBestBlock() == pindexDelete->GetBlockHash());
        if (DisconnectBlock(block, pindexDelete, view) != DISCONNECT_OK)
            return error("DisconnectTip(): DisconnectBlock %s failed", pindexDelete->GetBlockHash().ToString());
        bool flushed = view.Flush();
        assert(flushed);
    }
    LogPrint(BCLog::BENCH, "- Disconnect block: %.2fms\n", (GetTimeMicros() - nStart) * MILLI);
    // Write the chain state to disk, if necessary.
    if (!FlushStateToDisk(chainparams, state, FLUSH_STATE_IF_NEEDED))
        return false;

    AssertLockHeld(cs_main);

    if (disconnectpool) {
        // Save transactions to re-add to mempool at end of reorg
        for (auto it = block.vtx.rbegin(); it != block.vtx.rend(); ++it) {
            disconnectpool->addTransaction(*it);
        }
        while (disconnectpool->DynamicMemoryUsage() > MAX_DISCONNECTED_TX_POOL_SIZE * 1000) {
            // Drop the earliest entry, and remove its children from the mempool.
            auto it = disconnectpool->queuedTx.get<insertion_order>().begin();
            mempool.removeRecursive(**it, MemPoolRemovalReason::REORG);
            disconnectpool->removeEntry(it);
        }
    }

    chainActive.SetTip(pindexDelete->pprev);

    UpdateTip(pindexDelete->pprev, chainparams);
    // Let wallets know transactions went from 1-confirmed to
    // 0-confirmed or conflicted:
    GetMainSignals().BlockDisconnected(pblock, pindexDelete);
    return true;
}

static int64_t nTimeReadFromDisk = 0;
static int64_t nTimeConnectTotal = 0;
static int64_t nTimeFlush = 0;
static int64_t nTimeChainState = 0;
static int64_t nTimePostConnect = 0;

struct PerBlockConnectTrace {
    CBlockIndex* pindex = nullptr;
    std::shared_ptr<const CBlock> pblock;
    std::shared_ptr<std::vector<CTransactionRef>> conflictedTxs;
    PerBlockConnectTrace() : conflictedTxs(std::make_shared<std::vector<CTransactionRef>>()) {}
};
/**
 * Used to track blocks whose transactions were applied to the UTXO state as a
 * part of a single ActivateBestChainStep call.
 *
 * This class also tracks transactions that are removed from the mempool as
 * conflicts (per block) and can be used to pass all those transactions
 * through SyncTransaction.
 *
 * This class assumes (and asserts) that the conflicted transactions for a given
 * block are added via mempool callbacks prior to the BlockConnected() associated
 * with those transactions. If any transactions are marked conflicted, it is
 * assumed that an associated block will always be added.
 *
 * This class is single-use, once you call GetBlocksConnected() you have to throw
 * it away and make a new one.
 */
class ConnectTrace {
private:
    std::vector<PerBlockConnectTrace> blocksConnected;
    CTxMemPool &pool;

public:
    explicit ConnectTrace(CTxMemPool &_pool) : blocksConnected(1), pool(_pool) {
        pool.NotifyEntryRemoved.connect(boost::bind(&ConnectTrace::NotifyEntryRemoved, this, _1, _2));
    }

    ~ConnectTrace() {
        pool.NotifyEntryRemoved.disconnect(boost::bind(&ConnectTrace::NotifyEntryRemoved, this, _1, _2));
    }

    void BlockConnected(CBlockIndex* pindex, std::shared_ptr<const CBlock> pblock) {
        assert(!blocksConnected.back().pindex);
        assert(pindex);
        assert(pblock);
        blocksConnected.back().pindex = pindex;
        blocksConnected.back().pblock = std::move(pblock);
        blocksConnected.emplace_back();
    }

    std::vector<PerBlockConnectTrace>& GetBlocksConnected() {
        // We always keep one extra block at the end of our list because
        // blocks are added after all the conflicted transactions have
        // been filled in. Thus, the last entry should always be an empty
        // one waiting for the transactions from the next block. We pop
        // the last entry here to make sure the list we return is sane.
        assert(!blocksConnected.back().pindex);
        assert(blocksConnected.back().conflictedTxs->empty());
        blocksConnected.pop_back();
        return blocksConnected;
    }

    void NotifyEntryRemoved(CTransactionRef txRemoved, MemPoolRemovalReason reason) {
        assert(!blocksConnected.back().pindex);
        switch (reason) {
          case MemPoolRemovalReason::CONFLICT:
            blocksConnected.back().conflictedTxs->emplace_back(std::move(txRemoved));
            break;
          default:
            break;
        }
    }
};

/**
 * Connect a new block to chainActive. pblock is either nullptr or a pointer to a CBlock
 * corresponding to pindexNew, to bypass loading it again from disk.
 *
 * The block is added to connectTrace if connection succeeds.
 */
bool CChainState::ConnectTip(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexNew, const std::shared_ptr<const CBlock>& pblock, ConnectTrace& connectTrace, DisconnectedBlockTransactions &disconnectpool)
{
    assert(pindexNew->pprev == chainActive.Tip());
    // Read block from disk.
    int64_t nTime1 = GetTimeMicros();
    std::shared_ptr<const CBlock> pthisBlock;
    if (!pblock) {
        std::shared_ptr<CBlock> pblockNew = std::make_shared<CBlock>();
        if (!ReadBlockFromDisk(*pblockNew, pindexNew, chainparams.GetConsensus()))
            return AbortNode(state, "Failed to read block");
        pthisBlock = pblockNew;
    } else {
        pthisBlock = pblock;
    }
    const CBlock& blockConnecting = *pthisBlock;
    // Apply the block atomically to the chain state.
    int64_t nTime2 = GetTimeMicros(); nTimeReadFromDisk += nTime2 - nTime1;
    int64_t nTime3;
    LogPrint(BCLog::BENCH, "  - Load block from disk: %.2fms [%.2fs]\n", (nTime2 - nTime1) * MILLI, nTimeReadFromDisk * MICRO);
    {
        CCoinsViewCache view(pcoinsTip.get());
        bool rv = ConnectBlock(blockConnecting, state, pindexNew, view, chainparams);
        GetMainSignals().BlockChecked(blockConnecting, state);
        if (!rv) {
            if (state.IsInvalid())
                InvalidBlockFound(pindexNew, state);
            return error("ConnectTip(): ConnectBlock %s failed", pindexNew->GetBlockHash().ToString());
        }
        nTime3 = GetTimeMicros(); nTimeConnectTotal += nTime3 - nTime2;
        LogPrint(BCLog::BENCH, "  - Connect total: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime3 - nTime2) * MILLI, nTimeConnectTotal * MICRO, nTimeConnectTotal * MILLI / nBlocksTotal);
        bool flushed = view.Flush();
        assert(flushed);
    }
    int64_t nTime4 = GetTimeMicros(); nTimeFlush += nTime4 - nTime3;
    LogPrint(BCLog::BENCH, "  - Flush: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime4 - nTime3) * MILLI, nTimeFlush * MICRO, nTimeFlush * MILLI / nBlocksTotal);
    // Write the chain state to disk, if necessary.
    if (!FlushStateToDisk(chainparams, state, FLUSH_STATE_IF_NEEDED))
        return false;
    int64_t nTime5 = GetTimeMicros(); nTimeChainState += nTime5 - nTime4;
    LogPrint(BCLog::BENCH, "  - Writing chainstate: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime5 - nTime4) * MILLI, nTimeChainState * MICRO, nTimeChainState * MILLI / nBlocksTotal);
    // Remove conflicting transactions from the mempool.;
    mempool.removeForBlock(blockConnecting.vtx, pindexNew->nHeight);
    disconnectpool.removeForBlock(blockConnecting.vtx);
    // Update chainActive & related variables.
    chainActive.SetTip(pindexNew);
    UpdateTip(pindexNew, chainparams);

    int64_t nTime6 = GetTimeMicros(); nTimePostConnect += nTime6 - nTime5; nTimeTotal += nTime6 - nTime1;
    LogPrint(BCLog::BENCH, "  - Connect postprocess: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime6 - nTime5) * MILLI, nTimePostConnect * MICRO, nTimePostConnect * MILLI / nBlocksTotal);
    LogPrint(BCLog::BENCH, "- Connect block: %.2fms [%.2fs (%.2fms/blk)]\n", (nTime6 - nTime1) * MILLI, nTimeTotal * MICRO, nTimeTotal * MILLI / nBlocksTotal);

    connectTrace.BlockConnected(pindexNew, std::move(pthisBlock));
    komodo_connectblock(pindexNew,*(CBlock *)&blockConnecting);
    return true;
}

/**
 * Return the tip of the chain with the most work in it, that isn't
 * known to be invalid (it's however far from certain to be valid).
 */
CBlockIndex* CChainState::FindMostWorkChain() {
    do {
        CBlockIndex *pindexNew = nullptr;

        // Find the best candidate header.
        {
            std::set<CBlockIndex*, CBlockIndexWorkComparator>::reverse_iterator it = setBlockIndexCandidates.rbegin();
            if (it == setBlockIndexCandidates.rend())
                return nullptr;
            pindexNew = *it;
        }

        // Check whether all blocks on the path between the currently active chain and the candidate are valid.
        // Just going until the active chain is an optimization, as we know all blocks in it are valid already.
        CBlockIndex *pindexTest = pindexNew;
        bool fInvalidAncestor = false;
        while (pindexTest && !chainActive.Contains(pindexTest)) {
            assert(pindexTest->nChainTx || pindexTest->nHeight == 0);

            // Pruned nodes may have entries in setBlockIndexCandidates for
            // which block files have been deleted.  Remove those as candidates
            // for the most work chain if we come across them; we can't switch
            // to a chain unless we have all the non-active-chain parent blocks.
            bool fFailedChain = pindexTest->nStatus & BLOCK_FAILED_MASK;
            bool fMissingData = !(pindexTest->nStatus & BLOCK_HAVE_DATA);
            if (fFailedChain || fMissingData) {
                // Candidate chain is not usable (either invalid or missing data)
                if (fFailedChain && (pindexBestInvalid == nullptr || pindexNew->nChainWork > pindexBestInvalid->nChainWork))
                    pindexBestInvalid = pindexNew;
                CBlockIndex *pindexFailed = pindexNew;
                // Remove the entire chain from the set.
                while (pindexTest != pindexFailed) {
                    if (fFailedChain) {
                        pindexFailed->nStatus |= BLOCK_FAILED_CHILD;
                    } else if (fMissingData) {
                        // If we're missing data, then add back to mapBlocksUnlinked,
                        // so that if the block arrives in the future we can try adding
                        // to setBlockIndexCandidates again.
                        mapBlocksUnlinked.insert(std::make_pair(pindexFailed->pprev, pindexFailed));
                    }
                    setBlockIndexCandidates.erase(pindexFailed);
                    pindexFailed = pindexFailed->pprev;
                }
                setBlockIndexCandidates.erase(pindexTest);
                fInvalidAncestor = true;
                break;
            }
            pindexTest = pindexTest->pprev;
        }
        if (!fInvalidAncestor)
            return pindexNew;
    } while(true);
}

/** Delete all entries in setBlockIndexCandidates that are worse than the current tip. */
void CChainState::PruneBlockIndexCandidates() {
    // Note that we can't delete the current block itself, as we may need to return to it later in case a
    // reorganization to a better block fails.
    std::set<CBlockIndex*, CBlockIndexWorkComparator>::iterator it = setBlockIndexCandidates.begin();
    while (it != setBlockIndexCandidates.end() && setBlockIndexCandidates.value_comp()(*it, chainActive.Tip())) {
        setBlockIndexCandidates.erase(it++);
    }
    // Either the current tip or a successor of it we're working towards is left in setBlockIndexCandidates.
    assert(!setBlockIndexCandidates.empty());
}

/**
 * Try to make some progress towards making pindexMostWork the active block.
 * pblock is either nullptr or a pointer to a CBlock corresponding to pindexMostWork.
 */
bool CChainState::ActivateBestChainStep(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexMostWork, const std::shared_ptr<const CBlock>& pblock, bool& fInvalidFound, ConnectTrace& connectTrace)
{
    AssertLockHeld(cs_main);

    const CBlockIndex *pindexOldTip = chainActive.Tip();
    const CBlockIndex *pindexFork = chainActive.FindFork(pindexMostWork);

    // Disconnect active blocks which are no longer in the best chain.
    bool fBlocksDisconnected = false;
    DisconnectedBlockTransactions disconnectpool;
    while (chainActive.Tip() && chainActive.Tip() != pindexFork) {
        if (!DisconnectTip(state, chainparams, &disconnectpool)) {
            // This is likely a fatal error, but keep the mempool consistent,
            // just in case. Only remove from the mempool in this case.
            UpdateMempoolForReorg(disconnectpool, false);
            return false;
        }
        fBlocksDisconnected = true;
    }

    // Build list of new blocks to connect.
    std::vector<CBlockIndex*> vpindexToConnect;
    bool fContinue = true;
    int nHeight = pindexFork ? pindexFork->nHeight : -1;
    while (fContinue && nHeight != pindexMostWork->nHeight) {
        // Don't iterate the entire list of potential improvements toward the best tip, as we likely only need
        // a few blocks along the way.
        int nTargetHeight = std::min(nHeight + 32, pindexMostWork->nHeight);
        vpindexToConnect.clear();
        vpindexToConnect.reserve(nTargetHeight - nHeight);
        CBlockIndex *pindexIter = pindexMostWork->GetAncestor(nTargetHeight);
        while (pindexIter && pindexIter->nHeight != nHeight) {
            vpindexToConnect.push_back(pindexIter);
            pindexIter = pindexIter->pprev;
        }
        nHeight = nTargetHeight;

        // Connect new blocks.
        for (CBlockIndex *pindexConnect : reverse_iterate(vpindexToConnect)) {
            if (!ConnectTip(state, chainparams, pindexConnect, pindexConnect == pindexMostWork ? pblock : std::shared_ptr<const CBlock>(), connectTrace, disconnectpool)) {
                if (state.IsInvalid()) {
                    // The block violates a consensus rule.
                    if (!state.CorruptionPossible())
                        InvalidChainFound(vpindexToConnect.back());
                    state = CValidationState();
                    fInvalidFound = true;
                    fContinue = false;
                    break;
                } else {
                    // A system error occurred (disk space, database error, ...).
                    // Make the mempool consistent with the current tip, just in case
                    // any observers try to use it before shutdown.
                    UpdateMempoolForReorg(disconnectpool, false);
                    return false;
                }
            } else {
                PruneBlockIndexCandidates();
                if (!pindexOldTip || chainActive.Tip()->nChainWork > pindexOldTip->nChainWork) {
                    // We're in a better position than we were. Return temporarily to release the lock.
                    fContinue = false;
                    break;
                }
            }
        }
    }

    if (fBlocksDisconnected) {
        // If any blocks were disconnected, disconnectpool may be non empty.  Add
        // any disconnected transactions back to the mempool.
        UpdateMempoolForReorg(disconnectpool, true);
    }
    mempool.check(pcoinsTip.get());

    // Callbacks/notifications for a new best chain.
    if (fInvalidFound)
        CheckForkWarningConditionsOnNewFork(vpindexToConnect.back());
    else
        CheckForkWarningConditions();

    return true;
}

static void NotifyHeaderTip() {
    bool fNotify = false;
    bool fInitialBlockDownload = false;
    static CBlockIndex* pindexHeaderOld = nullptr;
    CBlockIndex* pindexHeader = nullptr;
    {
        LOCK(cs_main);
        pindexHeader = pindexBestHeader;

        if (pindexHeader != pindexHeaderOld) {
            fNotify = true;
            fInitialBlockDownload = IsInitialBlockDownload();
            pindexHeaderOld = pindexHeader;
        }
    }
    // Send block tip changed notifications without cs_main
    if (fNotify) {
        uiInterface.NotifyHeaderTip(fInitialBlockDownload, pindexHeader);
    }
}

/**
 * Make the best chain active, in multiple steps. The result is either failure
 * or an activated best chain. pblock is either nullptr or a pointer to a block
 * that is already loaded (to avoid loading it again from disk).
 */
bool CChainState::ActivateBestChain(CValidationState &state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock) {
    // 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_cs_chainstate to enforce mutual exclusion so that only one caller may execute this function at a time
    LOCK(m_cs_chainstate);

    CBlockIndex *pindexMostWork = nullptr;
    CBlockIndex *pindexNewTip = nullptr;
    int nStopAtHeight = gArgs.GetArg("-stopatheight", DEFAULT_STOPATHEIGHT);
    do {
        boost::this_thread::interruption_point();

        if (GetMainSignals().CallbacksPending() > 10) {
            // 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.
            SyncWithValidationInterfaceQueue();
        }

        {
            LOCK(cs_main);
            CBlockIndex* starting_tip = chainActive.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).
                ConnectTrace connectTrace(mempool); // Destructed before cs_main is unlocked

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

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

                bool fInvalidFound = false;
                std::shared_ptr<const CBlock> nullBlockPtr;
                if (!ActivateBestChainStep(state, chainparams, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : nullBlockPtr, fInvalidFound, connectTrace))
                    return false;
                blocks_connected = true;

                if (fInvalidFound) {
                    // Wipe cache, we may need another branch now.
                    pindexMostWork = nullptr;
                }
                pindexNewTip = chainActive.Tip();

                for (const PerBlockConnectTrace& trace : connectTrace.GetBlocksConnected()) {
                    assert(trace.pblock && trace.pindex);
                    GetMainSignals().BlockConnected(trace.pblock, trace.pindex, trace.conflictedTxs);
                }
            } while (!chainActive.Tip() || (starting_tip && CBlockIndexWorkComparator()(chainActive.Tip(), starting_tip)));
            if (!blocks_connected) return true;

            const CBlockIndex* pindexFork = chainActive.FindFork(starting_tip);
            bool fInitialDownload = IsInitialBlockDownload();

            // Notify external listeners about the new tip.
            // Enqueue while holding cs_main to ensure that UpdatedBlockTip is called in the order in which blocks are connected
            if (pindexFork != pindexNewTip) {
                // Notify ValidationInterface subscribers
                GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload);

                // Always notify the UI if a new block tip was connected
                uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
            }
        }
        // When we reach this point, we switched to a new tip (stored in pindexNewTip).

        if (nStopAtHeight && pindexNewTip && pindexNewTip->nHeight >= nStopAtHeight) StartShutdown();

        // We check shutdown only after giving ActivateBestChainStep a chance to run once so that we
        // never shutdown before connecting the genesis block during LoadChainTip(). Previously this
        // caused an assert() failure during shutdown in such cases as the UTXO DB flushing checks
        // that the best block hash is non-null.
        if (ShutdownRequested())
            break;
    } while (pindexNewTip != pindexMostWork);
    CheckBlockIndex(chainparams.GetConsensus());

    // Write changes periodically to disk, after relay.
    if (!FlushStateToDisk(chainparams, state, FLUSH_STATE_PERIODIC)) {
        return false;
    }

    return true;
}

bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams, std::shared_ptr<const CBlock> pblock) {
    return g_chainstate.ActivateBestChain(state, chainparams, std::move(pblock));
}

bool CChainState::PreciousBlock(CValidationState& state, const CChainParams& params, CBlockIndex *pindex)
{
    {
        LOCK(cs_main);
        if (pindex->nChainWork < chainActive.Tip()->nChainWork) {
            // Nothing to do, this block is not at the tip.
            return true;
        }
        if (chainActive.Tip()->nChainWork > nLastPreciousChainwork) {
            // The chain has been extended since the last call, reset the counter.
            nBlockReverseSequenceId = -1;
        }
        nLastPreciousChainwork = chainActive.Tip()->nChainWork;
        setBlockIndexCandidates.erase(pindex);
        pindex->nSequenceId = nBlockReverseSequenceId;
        if (nBlockReverseSequenceId > std::numeric_limits<int32_t>::min()) {
            // We can't keep reducing the counter if somebody really wants to
            // call preciousblock 2**31-1 times on the same set of tips...
            nBlockReverseSequenceId--;
        }
        if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && pindex->nChainTx) {
            setBlockIndexCandidates.insert(pindex);
            PruneBlockIndexCandidates();
        }
    }

    return ActivateBestChain(state, params, std::shared_ptr<const CBlock>());
}
bool PreciousBlock(CValidationState& state, const CChainParams& params, CBlockIndex *pindex) {
    return g_chainstate.PreciousBlock(state, params, pindex);
}

bool CChainState::InvalidateBlock(CValidationState& state, const CChainParams& chainparams, CBlockIndex *pindex)
{
    AssertLockHeld(cs_main);

    // We first disconnect backwards and then mark the blocks as invalid.
    // This prevents a case where pruned nodes may fail to invalidateblock
    // and be left unable to start as they have no tip candidates (as there
    // are no blocks that meet the "have data and are not invalid per
    // nStatus" criteria for inclusion in setBlockIndexCandidates).

    bool pindex_was_in_chain = false;
    CBlockIndex *invalid_walk_tip = chainActive.Tip();

    DisconnectedBlockTransactions disconnectpool;
    while (chainActive.Contains(pindex)) {
        pindex_was_in_chain = true;
        // ActivateBestChain considers blocks already in chainActive
        // unconditionally valid already, so force disconnect away from it.
        if (!DisconnectTip(state, chainparams, &disconnectpool)) {
            // It's probably hopeless to try to make the mempool consistent
            // here if DisconnectTip failed, but we can try.
            UpdateMempoolForReorg(disconnectpool, false);
            return false;
        }
    }

    // Now mark the blocks we just disconnected as descendants invalid
    // (note this may not be all descendants).
    while (pindex_was_in_chain && invalid_walk_tip != pindex) {
        invalid_walk_tip->nStatus |= BLOCK_FAILED_CHILD;
        setDirtyBlockIndex.insert(invalid_walk_tip);
        setBlockIndexCandidates.erase(invalid_walk_tip);
        invalid_walk_tip = invalid_walk_tip->pprev;
    }

    // Mark the block itself as invalid.
    pindex->nStatus |= BLOCK_FAILED_VALID;
    setDirtyBlockIndex.insert(pindex);
    setBlockIndexCandidates.erase(pindex);
    g_failed_blocks.insert(pindex);

    // DisconnectTip will add transactions to disconnectpool; try to add these
    // back to the mempool.
    UpdateMempoolForReorg(disconnectpool, true);

    // The resulting new best tip may not be in setBlockIndexCandidates anymore, so
    // add it again.
    BlockMap::iterator it = mapBlockIndex.begin();
    while (it != mapBlockIndex.end()) {
        if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && !setBlockIndexCandidates.value_comp()(it->second, chainActive.Tip())) {
            setBlockIndexCandidates.insert(it->second);
        }
        it++;
    }

    InvalidChainFound(pindex);
    uiInterface.NotifyBlockTip(IsInitialBlockDownload(), pindex->pprev);
    return true;
}
bool InvalidateBlock(CValidationState& state, const CChainParams& chainparams, CBlockIndex *pindex) {
    return g_chainstate.InvalidateBlock(state, chainparams, pindex);
}

bool CChainState::ResetBlockFailureFlags(CBlockIndex *pindex) {
    AssertLockHeld(cs_main);

    int nHeight = pindex->nHeight;

    // Remove the invalidity flag from this block and all its descendants.
    BlockMap::iterator it = mapBlockIndex.begin();
    while (it != mapBlockIndex.end()) {
        if (!it->second->IsValid() && it->second->GetAncestor(nHeight) == pindex) {
            it->second->nStatus &= ~BLOCK_FAILED_MASK;
            setDirtyBlockIndex.insert(it->second);
            if (it->second->IsValid(BLOCK_VALID_TRANSACTIONS) && it->second->nChainTx && setBlockIndexCandidates.value_comp()(chainActive.Tip(), it->second)) {
                setBlockIndexCandidates.insert(it->second);
            }
            if (it->second == pindexBestInvalid) {
                // Reset invalid block marker if it was pointing to one of those.
                pindexBestInvalid = nullptr;
            }
            g_failed_blocks.erase(it->second);
        }
        it++;
    }

    // Remove the invalidity flag from all ancestors too.
    while (pindex != nullptr) {
        if (pindex->nStatus & BLOCK_FAILED_MASK) {
            pindex->nStatus &= ~BLOCK_FAILED_MASK;
            setDirtyBlockIndex.insert(pindex);
            g_failed_blocks.erase(pindex);
        }
        pindex = pindex->pprev;
    }
    return true;
}
bool ResetBlockFailureFlags(CBlockIndex *pindex) {
    return g_chainstate.ResetBlockFailureFlags(pindex);
}

CBlockIndex* CChainState::AddToBlockIndex(const CBlockHeader& block)
{
    // Check for duplicate
    uint256 hash = block.GetHash();
    BlockMap::iterator it = mapBlockIndex.find(hash);
    if (it != mapBlockIndex.end())
        return it->second;

    // Construct new block index object
    CBlockIndex* pindexNew = new CBlockIndex(block);
    // We assign the sequence id to blocks only when the full data is available,
    // to avoid miners withholding blocks but broadcasting headers, to get a
    // competitive advantage.
    pindexNew->nSequenceId = 0;
    BlockMap::iterator mi = mapBlockIndex.insert(std::make_pair(hash, pindexNew)).first;
    pindexNew->phashBlock = &((*mi).first);
    BlockMap::iterator miPrev = mapBlockIndex.find(block.hashPrevBlock);
    if (miPrev != mapBlockIndex.end())
    {
        pindexNew->pprev = (*miPrev).second;
        pindexNew->nHeight = pindexNew->pprev->nHeight + 1;
        pindexNew->BuildSkip();
    }
    pindexNew->nTimeMax = (pindexNew->pprev ? std::max(pindexNew->pprev->nTimeMax, pindexNew->nTime) : pindexNew->nTime);
    pindexNew->nChainWork = (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) + GetBlockProof(*pindexNew);
    pindexNew->RaiseValidity(BLOCK_VALID_TREE);
    if (pindexBestHeader == nullptr || pindexBestHeader->nChainWork < pindexNew->nChainWork)
        pindexBestHeader = pindexNew;

    setDirtyBlockIndex.insert(pindexNew);

    return pindexNew;
}

/** Mark a block as having its data received and checked (up to BLOCK_VALID_TRANSACTIONS). */
bool CChainState::ReceivedBlockTransactions(const CBlock &block, CValidationState& state, CBlockIndex *pindexNew, const CDiskBlockPos& pos, const Consensus::Params& consensusParams)
{
    pindexNew->nTx = block.vtx.size();
    pindexNew->nChainTx = 0;
    pindexNew->nFile = pos.nFile;
    pindexNew->nDataPos = pos.nPos;
    pindexNew->nUndoPos = 0;
    pindexNew->nStatus |= BLOCK_HAVE_DATA;
    if (IsWitnessEnabled(pindexNew->pprev, consensusParams)) {
        pindexNew->nStatus |= BLOCK_OPT_WITNESS;
    }
    pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS);
    setDirtyBlockIndex.insert(pindexNew);

    if (pindexNew->pprev == nullptr || pindexNew->pprev->nChainTx) {
        // If pindexNew is the genesis block or all parents are BLOCK_VALID_TRANSACTIONS.
        std::deque<CBlockIndex*> queue;
        queue.push_back(pindexNew);

        // Recursively process any descendant blocks that now may be eligible to be connected.
        while (!queue.empty()) {
            CBlockIndex *pindex = queue.front();
            queue.pop_front();
            pindex->nChainTx = (pindex->pprev ? pindex->pprev->nChainTx : 0) + pindex->nTx;
            {
                LOCK(cs_nBlockSequenceId);
                pindex->nSequenceId = nBlockSequenceId++;
            }
            if (chainActive.Tip() == nullptr || !setBlockIndexCandidates.value_comp()(pindex, chainActive.Tip())) {
                setBlockIndexCandidates.insert(pindex);
            }
            std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = mapBlocksUnlinked.equal_range(pindex);
            while (range.first != range.second) {
                std::multimap<CBlockIndex*, CBlockIndex*>::iterator it = range.first;
                queue.push_back(it->second);
                range.first++;
                mapBlocksUnlinked.erase(it);
            }
        }
    } else {
        if (pindexNew->pprev && pindexNew->pprev->IsValid(BLOCK_VALID_TREE)) {
            mapBlocksUnlinked.insert(std::make_pair(pindexNew->pprev, pindexNew));
        }
    }

    return true;
}

static bool FindBlockPos(CDiskBlockPos &pos, unsigned int nAddSize, unsigned int nHeight, uint64_t nTime, bool fKnown = false)
{
    LOCK(cs_LastBlockFile);

    unsigned int nFile = fKnown ? pos.nFile : nLastBlockFile;
    if (vinfoBlockFile.size() <= nFile) {
        vinfoBlockFile.resize(nFile + 1);
    }

    if (!fKnown) {
        while (vinfoBlockFile[nFile].nSize + nAddSize >= MAX_BLOCKFILE_SIZE) {
            nFile++;
            if (vinfoBlockFile.size() <= nFile) {
                vinfoBlockFile.resize(nFile + 1);
            }
        }
        pos.nFile = nFile;
        pos.nPos = vinfoBlockFile[nFile].nSize;
    }

    if ((int)nFile != nLastBlockFile) {
        if (!fKnown) {
            LogPrintf("Leaving block file %i: %s\n", nLastBlockFile, vinfoBlockFile[nLastBlockFile].ToString());
        }
        FlushBlockFile(!fKnown);
        nLastBlockFile = nFile;
    }

    vinfoBlockFile[nFile].AddBlock(nHeight, nTime);
    if (fKnown)
        vinfoBlockFile[nFile].nSize = std::max(pos.nPos + nAddSize, vinfoBlockFile[nFile].nSize);
    else
        vinfoBlockFile[nFile].nSize += nAddSize;

    if (!fKnown) {
        unsigned int nOldChunks = (pos.nPos + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
        unsigned int nNewChunks = (vinfoBlockFile[nFile].nSize + BLOCKFILE_CHUNK_SIZE - 1) / BLOCKFILE_CHUNK_SIZE;
        if (nNewChunks > nOldChunks) {
            if (fPruneMode)
                fCheckForPruning = true;
            if (CheckDiskSpace(nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos)) {
                FILE *file = OpenBlockFile(pos);
                if (file) {
                    LogPrintf("Pre-allocating up to position 0x%x in blk%05u.dat\n", nNewChunks * BLOCKFILE_CHUNK_SIZE, pos.nFile);
                    AllocateFileRange(file, pos.nPos, nNewChunks * BLOCKFILE_CHUNK_SIZE - pos.nPos);
                    fclose(file);
                }
            }
            else
                return error("out of disk space");
        }
    }

    setDirtyFileInfo.insert(nFile);
    return true;
}

static bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos, unsigned int nAddSize)
{
    pos.nFile = nFile;

    LOCK(cs_LastBlockFile);

    unsigned int nNewSize;
    pos.nPos = vinfoBlockFile[nFile].nUndoSize;
    nNewSize = vinfoBlockFile[nFile].nUndoSize += nAddSize;
    setDirtyFileInfo.insert(nFile);

    unsigned int nOldChunks = (pos.nPos + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
    unsigned int nNewChunks = (nNewSize + UNDOFILE_CHUNK_SIZE - 1) / UNDOFILE_CHUNK_SIZE;
    if (nNewChunks > nOldChunks) {
        if (fPruneMode)
            fCheckForPruning = true;
        if (CheckDiskSpace(nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos)) {
            FILE *file = OpenUndoFile(pos);
            if (file) {
                LogPrintf("Pre-allocating up to position 0x%x in rev%05u.dat\n", nNewChunks * UNDOFILE_CHUNK_SIZE, pos.nFile);
                AllocateFileRange(file, pos.nPos, nNewChunks * UNDOFILE_CHUNK_SIZE - pos.nPos);
                fclose(file);
            }
        }
        else
            return state.Error("out of disk space");
    }

    return true;
}

/* Temporary check that blocks are compatible with BDB's 10,000 lock limit.
   This is based on Bitcoin's commit 8c222dca4f961ad13ec64d690134a40d09b20813.
   Each "object" touched in the DB may cause two locks (one read and one
   write lock).  Objects are transaction IDs and names.  Thus, count the
   total number of transaction IDs (tx themselves plus all distinct inputs).
   In addition, each SmartUSD transaction could touch at most one name,
   so add them as well.  */
bool CheckDbLockLimit(const std::vector<CTransactionRef>& vtx)
{
    std::set<uint256> setTxIds;
    unsigned nNames = 0;
    for (const auto& tx : vtx)
    {
        setTxIds.insert(tx->GetHash());

        for (const auto& txIn : tx->vin)
            setTxIds.insert(txIn.prevout.hash);
    }

    const unsigned nTotalIds = setTxIds.size() + nNames;
    if (nTotalIds > 4500)
        return error("%s : %u locks estimated, that is too much for BDB",
                     __func__, nTotalIds);

    //LogPrintf ("%s : need %u locks\n", __func__, nTotalIds);
    return true;
}

static bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW = true)
{
    // Check proof of work matches claimed amount
    if (fCheckPOW && !CheckProofOfWork(block, consensusParams))
        return state.DoS(50, false, REJECT_INVALID, "high-hash", false, "proof of work failed");

    return true;
}

bool CCTxFixAcceptToMemPoolUnchecked(CTxMemPool& pool, const CTransactionRef &tx)
{
    // called from CheckBlock which is in cs_main and mempool.cs locks already.
    LockPoints lp;
    CTxMemPoolEntry entry(tx, 0, GetTime(), chainActive.Height(), false, 4, lp);
    // LogPrintf( "adding %s to mempool from block %d\n",tx.GetHash().ToString().c_str(),chainActive.GetHeight());
    // std::cerr << __func__ << "adding " << tx->GetHash().ToString() << "to mempool from block " << chainActive.Tip()->GetHeight() << std::endl;
    pool.addUnchecked(tx->GetHash(), entry, false);
    return true;
}

bool myAddtomempool(CTransaction &tx, CValidationState *pstate, bool fSkipExpiry)
{
    CValidationState state;
    if (!pstate)
        pstate = &state;
    CTransaction Ltx; bool fMissingInputs,fOverrideFees = false;
    if ( mempool.lookup(tx.GetHash(),Ltx) == 0 )
    {
        if ( !fSkipExpiry )
            return(AcceptToMemoryPool(mempool, *pstate, MakeTransactionRef(tx), &fMissingInputs, nullptr, true, 0));
        else
            return(CCTxFixAcceptToMemPoolUnchecked(mempool,MakeTransactionRef(tx)));
    }
    else return(true);
}

bool CheckBlock(const CBlock& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW, bool fCheckMerkleRoot)
{
    // These are checks that are independent of context.

    if (block.fChecked)
        return true;

    // Check that the header is valid (particularly PoW).  This is mostly
    // redundant with the call in AcceptBlockHeader.
    if (!CheckBlockHeader(block, state, consensusParams, fCheckPOW))
        return false;

    // Check the merkle root.
    if (fCheckMerkleRoot) {
        bool mutated;
        uint256 hashMerkleRoot2 = BlockMerkleRoot(block, &mutated);
        if (block.hashMerkleRoot != hashMerkleRoot2)
            return state.DoS(100, false, REJECT_INVALID, "bad-txnmrklroot", true, "hashMerkleRoot mismatch");

        // Check for merkle tree malleability (CVE-2012-2459): repeating sequences
        // of transactions in a block without affecting the merkle root of a block,
        // while still invalidating it.
        if (mutated)
            return state.DoS(100, false, REJECT_INVALID, "bad-txns-duplicate", true, "duplicate transaction");
    }

    // All potential-corruption validation must be done before we do any
    // transaction validation, as otherwise we may mark the header as invalid
    // because we receive the wrong transactions for it.
    // Note that witness malleability is checked in ContextualCheckBlock, so no
    // checks that use witness data may be performed here.

    // Size limits
    if (block.vtx.empty() || block.vtx.size() * WITNESS_SCALE_FACTOR > MAX_BLOCK_WEIGHT || ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) * WITNESS_SCALE_FACTOR > MAX_BLOCK_WEIGHT)
        return state.DoS(100, false, REJECT_INVALID, "bad-blk-length", false, "size limits failed");

    // Enforce the temporary DB lock limit.
    // TODO: Remove with a hardfork in the future.
    if (!CheckDbLockLimit(block.vtx))
        return state.DoS(100, error("%s : DB lock limit failed", __func__),
                         REJECT_INVALID, "bad-db-locks");

    // First transaction must be coinbase, the rest must not be
    if (block.vtx.empty() || !block.vtx[0]->IsCoinBase())
        return state.DoS(100, false, REJECT_INVALID, "bad-cb-missing", false, "first tx is not coinbase");
    for (unsigned int i = 1; i < block.vtx.size(); i++)
        if (block.vtx[i]->IsCoinBase())
            return state.DoS(100, false, REJECT_INVALID, "bad-cb-multiple", false, "more than one coinbase");

    // Check transactions
    CTransaction sTx;
    CTransaction *ptx = NULL;
    if ( ASSETCHAINS_CC != 0 && !fCheckPOW )
        return true;

    /*
    if ( ASSETCHAINS_CC != 0 ) // CC contracts might refer to transactions in the current block, from a CC spend within the same block and out of order
    {
        int32_t i,j,rejects=0,lastrejects=0;
        //LogPrintf("put block's tx into mempool\n");
        // Copy all non Z-txs in mempool to temporary mempool because there can be tx in local mempool that make the block invalid.
        LOCK2(cs_main,mempool.cs);
        //LogPrintf( "starting... mempoolsize.%ld\n",mempool.size());
        std::list<CTransaction> transactionsToRemove;
        BOOST_FOREACH(const CTxMemPoolEntry& e, mempool.mapTx) {
            const CTransaction &tx = e.GetTx();
            const uint256 &hash = tx.GetHash();
            transactionsToRemove.push_back(tx);
            tmpmempool.addUnchecked(hash,e,true);
        }
        BOOST_FOREACH(const CTransaction& tx, transactionsToRemove) {
            std::list<CTransaction> removed;
            mempool.remove(tx, removed, false);
        }
        // add all the txs in the block to the empty mempool.
        // CC validation shouldnt (cant) depend on the state of mempool!

        // TODO: myAddtomempool -> CCTxFixAcceptToMemPoolUnchecked -> pool.addUnchecked ->
        // bool CTxMemPool::addUnchecked(...) cause crash bcz of bad entries in mapLinks map.
        // Code above and below and probably CCTxFixAcceptToMemPoolUnchecked should be
        // re-factored / re-written to correct handle / deal with mapLinks.  For now change (A)
        // is done to prevent call CCTxFixAcceptToMemPoolUnchecked.

        while ( 1 )
        {
            std::list<CTransaction> removed;
            for (i=0; i<block.vtx.size(); i++)
            {
                CValidationState state; CTransaction Tx;
                const CTransaction &tx = *(block.vtx[i].get());
                if ( tx.IsCoinBase() )
                    continue;
                Tx = tx;
                // if ( myAddtomempool(Tx, &state, true) == false ) // happens with out of order tx in block on resync
                if ( myAddtomempool(Tx, &state, false) == false ) // change (A)
                {
                    //LogPrintf("Rejected by mempool, reason: .%s.\n", state.GetRejectReason().c_str());
                    // take advantage of other checks, but if we were only rejected because it is a valid staking
                    // transaction, sync with wallets and don't mark as a reject
                    rejects++;
                }
                // here we remove any txs in the temp mempool that were included in the block.
                tmpmempool.remove(tx, removed, false);
            }
            //LogPrintf( "removed.%ld\n",removed.size());
            if ( rejects == 0 || rejects == lastrejects )
            {
                if ( 0 && lastrejects != 0 )
                    LogPrintf("lastrejects.%d -> all tx in mempool\n",lastrejects);
                break;
            }
            //LogPrintf("addtomempool ht.%d for CC checking: n.%d rejects.%d last.%d\n",height,(int32_t)block.vtx.size(),rejects,lastrejects);
            lastrejects = rejects;
            rejects = 0;
        }
        //LogPrintf("done putting block's tx into mempool\n");
    }
    */

    for (const auto& tx : block.vtx)
        if (!CheckTransaction(*tx, state, true))
            return state.Invalid(false, state.GetRejectCode(), state.GetRejectReason(),
                                 strprintf("Transaction check failed (tx hash %s) %s", tx->GetHash().ToString(), state.GetDebugMessage()));

    unsigned int nSigOps = 0;
    for (const auto& tx : block.vtx)
    {
        nSigOps += GetLegacySigOpCount(*tx);
    }
    if (nSigOps * WITNESS_SCALE_FACTOR > MAX_BLOCK_SIGOPS_COST)
        return state.DoS(100, false, REJECT_INVALID, "bad-blk-sigops", false, "out-of-bounds SigOpCount");

    if (fCheckPOW && fCheckMerkleRoot)
        block.fChecked = true;

    /*
    if ( ASSETCHAINS_CC != 0 )
    {
        LOCK2(cs_main,mempool.cs);
        // here we add back all txs from the temp mempool to the main mempool.
        BOOST_FOREACH(const CTxMemPoolEntry& e, tmpmempool.mapTx)
        {
            const CTransaction &tx = e.GetTx();
            const uint256 &hash = tx.GetHash();
            CTransaction resulttx;
            if (!mempool.lookup(hash, resulttx))
                mempool.addUnchecked(hash,e,true);
        }
        //LogPrintf( "finished adding back. mempoolsize.%ld\n",mempool.size());
        // empty the temp mempool for next time.
        tmpmempool.clear();
    }
    */

    return true;
}

bool IsWitnessEnabled(const CBlockIndex* pindexPrev, const Consensus::Params& params)
{
    LOCK(cs_main);
    return (VersionBitsState(pindexPrev, params, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == THRESHOLD_ACTIVE);
}

// Compute at which vout of the block's coinbase transaction the witness
// commitment occurs, or -1 if not found.
static int GetWitnessCommitmentIndex(const CBlock& block)
{
    int commitpos = -1;
    if (!block.vtx.empty()) {
        for (size_t o = 0; o < block.vtx[0]->vout.size(); o++) {
            if (block.vtx[0]->vout[o].scriptPubKey.size() >= 38 && block.vtx[0]->vout[o].scriptPubKey[0] == OP_RETURN && block.vtx[0]->vout[o].scriptPubKey[1] == 0x24 && block.vtx[0]->vout[o].scriptPubKey[2] == 0xaa && block.vtx[0]->vout[o].scriptPubKey[3] == 0x21 && block.vtx[0]->vout[o].scriptPubKey[4] == 0xa9 && block.vtx[0]->vout[o].scriptPubKey[5] == 0xed) {
                commitpos = o;
            }
        }
    }
    return commitpos;
}

void UpdateUncommittedBlockStructures(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams)
{
    int commitpos = GetWitnessCommitmentIndex(block);
    static const std::vector<unsigned char> nonce(32, 0x00);
    if (commitpos != -1 && IsWitnessEnabled(pindexPrev, consensusParams) && !block.vtx[0]->HasWitness()) {
        CMutableTransaction tx(*block.vtx[0]);
        tx.vin[0].scriptWitness.stack.resize(1);
        tx.vin[0].scriptWitness.stack[0] = nonce;
        block.vtx[0] = MakeTransactionRef(std::move(tx));
    }
}

std::vector<unsigned char> GenerateCoinbaseCommitment(CBlock& block, const CBlockIndex* pindexPrev, const Consensus::Params& consensusParams)
{
    std::vector<unsigned char> commitment;
    int commitpos = GetWitnessCommitmentIndex(block);
    std::vector<unsigned char> ret(32, 0x00);
    if (consensusParams.vDeployments[Consensus::DEPLOYMENT_SEGWIT].nTimeout != 0) {
        if (commitpos == -1) {
            uint256 witnessroot = BlockWitnessMerkleRoot(block, nullptr);
            CHash256().Write(witnessroot.begin(), 32).Write(ret.data(), 32).Finalize(witnessroot.begin());
            CTxOut out;
            out.nValue = 0;
            out.scriptPubKey.resize(38);
            out.scriptPubKey[0] = OP_RETURN;
            out.scriptPubKey[1] = 0x24;
            out.scriptPubKey[2] = 0xaa;
            out.scriptPubKey[3] = 0x21;
            out.scriptPubKey[4] = 0xa9;
            out.scriptPubKey[5] = 0xed;
            memcpy(&out.scriptPubKey[6], witnessroot.begin(), 32);
            commitment = std::vector<unsigned char>(out.scriptPubKey.begin(), out.scriptPubKey.end());
            CMutableTransaction tx(*block.vtx[0]);
            tx.vout.push_back(out);
            block.vtx[0] = MakeTransactionRef(std::move(tx));
        }
    }
    UpdateUncommittedBlockStructures(block, pindexPrev, consensusParams);
    return commitment;
}

/** Context-dependent validity checks.
 *  By "context", we mean only the previous block headers, but not the UTXO
 *  set; UTXO-related validity checks are done in ConnectBlock().
 *  NOTE: This function is not currently invoked by ConnectBlock(), so we
 *  should consider upgrade issues if we change which consensus rules are
 *  enforced in this function (eg by adding a new consensus rule). See comment
 *  in ConnectBlock().
 *  Note that -reindex-chainstate skips the validation that happens here!
 */
static bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, const CChainParams& params, const CBlockIndex* pindexPrev, int64_t nAdjustedTime)
{
    assert(pindexPrev != nullptr);
    const int nHeight = pindexPrev->nHeight + 1;

    //Komodo dPoW
    uint256 hash = block.GetHash();
    int32_t notarized_height;

    // Disallow legacy blocks after merge-mining start.
    const Consensus::Params& consensusParams = params.GetConsensus();
    if (!consensusParams.AllowLegacyBlocks(nHeight) && block.IsLegacy())
        return state.DoS(100, error("%s : legacy block after auxpow start",
                                    __func__),
                         REJECT_INVALID, "late-legacy-block");

    // Check proof of work
    if (block.nBits != GetNextWorkRequired(pindexPrev, &block, consensusParams))
        return state.DoS(100, false, REJECT_INVALID, "bad-diffbits", false, "incorrect proof of work");

    // Check against checkpoints
    if (fCheckpointsEnabled)
    {
        // Don't accept any forks from the main chain prior to last checkpoint.
        // GetLastCheckpoint finds the last checkpoint in MapCheckpoints that's in our
        // MapBlockIndex.
        CBlockIndex *pcheckpoint = Checkpoints::GetLastCheckpoint(params.Checkpoints());
        if (pcheckpoint && nHeight < pcheckpoint->nHeight)
            return state.DoS(100, error("%s: forked chain older than last checkpoint (height %d)", __func__, nHeight), REJECT_CHECKPOINT, "bad-fork-prior-to-checkpoint");
        else if ( komodo_checkpoint(&notarized_height,(int32_t)nHeight,hash) < 0 )
        {
            CBlockIndex *heightblock = chainActive[nHeight];
            if ( heightblock != 0 && heightblock->GetBlockHash() == hash )
            {
                //fprintf(stderr,"got a pre notarization block that matches height.%d\n",(int32_t)nHeight);
                return true;
            } else return state.DoS(100, error("%s: forked chain %d older than last notarized (height %d) vs %d", __func__,nHeight, notarized_height));
        }
    }

    // Check timestamp against prev
    if (block.GetBlockTime() <= pindexPrev->GetMedianTimePast())
        return state.Invalid(false, REJECT_INVALID, "time-too-old", "block's timestamp is too early");

    // Check timestamp
    if (block.GetBlockTime() > nAdjustedTime + MAX_FUTURE_BLOCK_TIME)
        return state.Invalid(false, REJECT_INVALID, "time-too-new", "block timestamp too far in the future");

    // Reject outdated version blocks when 95% (75% on testnet) of the network has upgraded:
    // check for version 2, 3 and 4 upgrades
    if((block.GetBaseVersion() < 2 && nHeight >= consensusParams.BIP34Height) ||
       (block.GetBaseVersion() < 3 && nHeight >= consensusParams.BIP66Height) ||
       (block.GetBaseVersion() < 4 && nHeight >= consensusParams.BIP65Height))
            return state.Invalid(false, REJECT_OBSOLETE, strprintf("bad-version(0x%08x)", block.nVersion),
                                 strprintf("rejected nVersion=0x%08x block", block.nVersion));

    return true;
}

/** NOTE: This function is not currently invoked by ConnectBlock(), so we
 *  should consider upgrade issues if we change which consensus rules are
 *  enforced in this function (eg by adding a new consensus rule). See comment
 *  in ConnectBlock().
 *  Note that -reindex-chainstate skips the validation that happens here!
 */
static bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
{
    const int nHeight = pindexPrev == nullptr ? 0 : pindexPrev->nHeight + 1;

    // Start enforcing BIP113 (Median Time Past) using versionbits logic.
    int nLockTimeFlags = 0;
    if (VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_CSV, versionbitscache) == THRESHOLD_ACTIVE) {
        nLockTimeFlags |= LOCKTIME_MEDIAN_TIME_PAST;
    }

    int64_t nLockTimeCutoff = (nLockTimeFlags & LOCKTIME_MEDIAN_TIME_PAST)
                              ? pindexPrev->GetMedianTimePast()
                              : block.GetBlockTime();

    // Check that all transactions are finalized
    for (const auto& tx : block.vtx) {
        if (!IsFinalTx(*tx, nHeight, nLockTimeCutoff)) {
            return state.DoS(10, false, REJECT_INVALID, "bad-txns-nonfinal", false, "non-final transaction");
        }
    }

    // Enforce rule that the coinbase starts with serialized block height
    if (nHeight >= consensusParams.BIP34Height)
    {
        CScript expect = CScript() << nHeight;
        if (block.vtx[0]->vin[0].scriptSig.size() < expect.size() ||
            !std::equal(expect.begin(), expect.end(), block.vtx[0]->vin[0].scriptSig.begin())) {
            return state.DoS(100, false, REJECT_INVALID, "bad-cb-height", false, "block height mismatch in coinbase");
        }
    }

    // Validation for witness commitments.
    // * We compute the witness hash (which is the hash including witnesses) of all the block's transactions, except the
    //   coinbase (where 0x0000....0000 is used instead).
    // * The coinbase scriptWitness is a stack of a single 32-byte vector, containing a witness nonce (unconstrained).
    // * We build a merkle tree with all those witness hashes as leaves (similar to the hashMerkleRoot in the block header).
    // * There must be at least one output whose scriptPubKey is a single 36-byte push, the first 4 bytes of which are
    //   {0xaa, 0x21, 0xa9, 0xed}, and the following 32 bytes are SHA256^2(witness root, witness nonce). In case there are
    //   multiple, the last one is used.
    bool fHaveWitness = false;
    if (VersionBitsState(pindexPrev, consensusParams, Consensus::DEPLOYMENT_SEGWIT, versionbitscache) == THRESHOLD_ACTIVE) {
        int commitpos = GetWitnessCommitmentIndex(block);
        if (commitpos != -1) {
            bool malleated = false;
            uint256 hashWitness = BlockWitnessMerkleRoot(block, &malleated);
            // The malleation check is ignored; as the transaction tree itself
            // already does not permit it, it is impossible to trigger in the
            // witness tree.
            if (block.vtx[0]->vin[0].scriptWitness.stack.size() != 1 || block.vtx[0]->vin[0].scriptWitness.stack[0].size() != 32) {
                return state.DoS(100, false, REJECT_INVALID, "bad-witness-nonce-size", true, strprintf("%s : invalid witness nonce size", __func__));
            }
            CHash256().Write(hashWitness.begin(), 32).Write(&block.vtx[0]->vin[0].scriptWitness.stack[0][0], 32).Finalize(hashWitness.begin());
            if (memcmp(hashWitness.begin(), &block.vtx[0]->vout[commitpos].scriptPubKey[6], 32)) {
                return state.DoS(100, false, REJECT_INVALID, "bad-witness-merkle-match", true, strprintf("%s : witness merkle commitment mismatch", __func__));
            }
            fHaveWitness = true;
        }
    }

    // No witness data is allowed in blocks that don't commit to witness data, as this would otherwise leave room for spam
    if (!fHaveWitness) {
      for (const auto& tx : block.vtx) {
            if (tx->HasWitness()) {
                return state.DoS(100, false, REJECT_INVALID, "unexpected-witness", true, strprintf("%s : unexpected witness data found", __func__));
            }
        }
    }

    // After the coinbase witness nonce and commitment are verified,
    // we can check if the block weight passes (before we've checked the
    // coinbase witness, it would be possible for the weight to be too
    // large by filling up the coinbase witness, which doesn't change
    // the block hash, so we couldn't mark the block as permanently
    // failed).
    if (GetBlockWeight(block) > MAX_BLOCK_WEIGHT) {
        return state.DoS(100, false, REJECT_INVALID, "bad-blk-weight", false, strprintf("%s : weight limit failed", __func__));
    }

    return true;
}

bool CChainState::AcceptBlockHeader(const CBlockHeader& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex)
{
    AssertLockHeld(cs_main);
    // Check for duplicate
    uint256 hash = block.GetHash();
    BlockMap::iterator miSelf = mapBlockIndex.find(hash);
    CBlockIndex *pindex = nullptr;
    if (hash != chainparams.GetConsensus().hashGenesisBlock) {

        if (miSelf != mapBlockIndex.end()) {
            // Block header is already known.
            pindex = miSelf->second;
            if (ppindex)
                *ppindex = pindex;
            if (pindex->nStatus & BLOCK_FAILED_MASK)
            {
                LogPrintf("reconsider block %s\n",hash.GetHex().c_str());
                pindex->nStatus &= ~BLOCK_FAILED_MASK;
            }
            return true;
        }

        if (!CheckBlockHeader(block, state, chainparams.GetConsensus()))
            return error("%s: Consensus::CheckBlockHeader: %s, %s", __func__, hash.ToString(), FormatStateMessage(state));

        // Get prev block index
        CBlockIndex* pindexPrev = nullptr;
        BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
        if (mi == mapBlockIndex.end())
            return state.DoS(10, error("%s: prev block not found", __func__), 0, "prev-blk-not-found");
        pindexPrev = (*mi).second;
        if (pindexPrev->nStatus & BLOCK_FAILED_MASK)
            return state.DoS(100, error("%s: prev block invalid", __func__), REJECT_INVALID, "bad-prevblk");
        if (!ContextualCheckBlockHeader(block, state, chainparams, pindexPrev, GetAdjustedTime()))
            return error("%s: Consensus::ContextualCheckBlockHeader: %s, %s", __func__, hash.ToString(), FormatStateMessage(state));

        if (!pindexPrev->IsValid(BLOCK_VALID_SCRIPTS)) {
            for (const CBlockIndex* failedit : g_failed_blocks) {
                if (pindexPrev->GetAncestor(failedit->nHeight) == failedit) {
                    assert(failedit->nStatus & BLOCK_FAILED_VALID);
                    CBlockIndex* invalid_walk = pindexPrev;
                    while (invalid_walk != failedit) {
                        invalid_walk->nStatus |= BLOCK_FAILED_CHILD;
                        setDirtyBlockIndex.insert(invalid_walk);
                        invalid_walk = invalid_walk->pprev;
                    }
                    return state.DoS(100, error("%s: prev block invalid", __func__), REJECT_INVALID, "bad-prevblk");
                }
            }
        }
    }
    if (pindex == nullptr)
        pindex = AddToBlockIndex(block);

    if (ppindex)
        *ppindex = pindex;

    CheckBlockIndex(chainparams.GetConsensus());

    return true;
}

// Exposed wrapper for AcceptBlockHeader
bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& headers, CValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex, CBlockHeader *first_invalid)
{
    if (first_invalid != nullptr) first_invalid->SetNull();
    {
        LOCK(cs_main);
        for (const CBlockHeader& header : headers) {
            CBlockIndex *pindex = nullptr; // Use a temp pindex instead of ppindex to avoid a const_cast
            if (!g_chainstate.AcceptBlockHeader(header, state, chainparams, &pindex)) {
                if (first_invalid) *first_invalid = header;
                return false;
            }
            if (ppindex) {
                *ppindex = pindex;
            }
        }
    }
    NotifyHeaderTip();
    return true;
}

/** Store block on disk. If dbp is non-nullptr, the file is known to already reside on disk */
static CDiskBlockPos SaveBlockToDisk(const CBlock& block, int nHeight, const CChainParams& chainparams, const CDiskBlockPos* dbp) {
    unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
    CDiskBlockPos blockPos;
    if (dbp != nullptr)
        blockPos = *dbp;
    if (!FindBlockPos(blockPos, nBlockSize+8, nHeight, block.GetBlockTime(), dbp != nullptr)) {
        error("%s: FindBlockPos failed", __func__);
        return CDiskBlockPos();
    }
    if (dbp == nullptr) {
        if (!WriteBlockToDisk(block, blockPos, chainparams.MessageStart())) {
            AbortNode("Failed to write block");
            return CDiskBlockPos();
        }
    }
    return blockPos;
}

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

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

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

    if (!AcceptBlockHeader(block, state, chainparams, &pindex))
        return false;

    // Try to process all requested blocks that we don't have, but only
    // process an unrequested block if it's new and has enough work to
    // advance our tip, and isn't too many blocks ahead.
    bool fAlreadyHave = pindex->nStatus & BLOCK_HAVE_DATA;
    bool fHasMoreOrSameWork = (chainActive.Tip() ? pindex->nChainWork >= chainActive.Tip()->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 > int(chainActive.Height() + 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.

    // 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 < nMinimumChainWork) return true;
    }
    if (fNewBlock) *fNewBlock = true;

    if (!CheckBlock(block, state, chainparams.GetConsensus()) ||
        !ContextualCheckBlock(block, state, chainparams.GetConsensus(), pindex->pprev)) {
        if (state.IsInvalid() && !state.CorruptionPossible()) {
            pindex->nStatus |= BLOCK_FAILED_VALID;
            setDirtyBlockIndex.insert(pindex);
        }
        return error("%s: %s", __func__, FormatStateMessage(state));
    }

    // Header is valid/has work, merkle tree and segwit merkle tree are good...RELAY NOW
    // (but if it does not build on our best tip, let the SendMessages loop relay it)
    if (!IsInitialBlockDownload() && chainActive.Tip() == pindex->pprev)
        GetMainSignals().NewPoWValidBlock(pindex, pblock);

    // Write block to history file
    try {
        CDiskBlockPos blockPos = SaveBlockToDisk(block, pindex->nHeight, chainparams, dbp);
        if (blockPos.IsNull()) {
            state.Error(strprintf("%s: Failed to find position to write new block to disk", __func__));
            return false;
        }
        if (!ReceivedBlockTransactions(block, state, pindex, blockPos, chainparams.GetConsensus()))
            return error("AcceptBlock(): ReceivedBlockTransactions failed");
    } catch (const std::runtime_error& e) {
        return AbortNode(state, std::string("System error: ") + e.what());
    }

    if (fCheckForPruning)
        FlushStateToDisk(chainparams, state, FLUSH_STATE_NONE); // we just allocated more disk space for block files

    CheckBlockIndex(chainparams.GetConsensus());

    return true;
}

bool ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<const CBlock> pblock, bool fForceProcessing, bool *fNewBlock)
{
    AssertLockNotHeld(cs_main);

    {
        CBlockIndex *pindex = nullptr;
        if (fNewBlock) *fNewBlock = false;
        CValidationState state;
        // Ensure that CheckBlock() passes before calling AcceptBlock, as
        // belt-and-suspenders.
        bool ret = CheckBlock(*pblock, state, chainparams.GetConsensus());

        LOCK(cs_main);

        if (ret) {
            // Store to disk
            ret = g_chainstate.AcceptBlock(pblock, state, chainparams, &pindex, fForceProcessing, nullptr, fNewBlock);
        }
        if (!ret) {
            GetMainSignals().BlockChecked(*pblock, state);
            return error("%s: AcceptBlock FAILED (%s)", __func__, state.GetDebugMessage());
        }
    }

    NotifyHeaderTip();

    CValidationState state; // Only used to report errors, not invalidity - ignore it
    if (!g_chainstate.ActivateBestChain(state, chainparams, pblock))
        return error("%s: ActivateBestChain failed", __func__);

    return true;
}

bool TestBlockValidity(CValidationState& state, const CChainParams& chainparams, const CBlock& block, CBlockIndex* pindexPrev, bool fCheckPOW, bool fCheckMerkleRoot)
{
    AssertLockHeld(cs_main);
    assert(pindexPrev && pindexPrev == chainActive.Tip());
    CCoinsViewCache viewNew(pcoinsTip.get());
    CBlockIndex indexDummy(block);
    indexDummy.pprev = pindexPrev;
    indexDummy.nHeight = pindexPrev->nHeight + 1;

    // NOTE: CheckBlockHeader is called by CheckBlock
    if (!ContextualCheckBlockHeader(block, state, chainparams, pindexPrev, GetAdjustedTime()))
        return error("%s: Consensus::ContextualCheckBlockHeader: %s", __func__, FormatStateMessage(state));
    if (!CheckBlock(block, state, chainparams.GetConsensus(), fCheckPOW, fCheckMerkleRoot))
        return error("%s: Consensus::CheckBlock: %s", __func__, FormatStateMessage(state));
    if (!ContextualCheckBlock(block, state, chainparams.GetConsensus(), pindexPrev))
        return error("%s: Consensus::ContextualCheckBlock: %s", __func__, FormatStateMessage(state));
    if (!g_chainstate.ConnectBlock(block, state, &indexDummy, viewNew, chainparams, true))
        return false;
    assert(state.IsValid());

    return true;
}

/**
 * BLOCK PRUNING CODE
 */

/* Calculate the amount of disk space the block & undo files currently use */
uint64_t CalculateCurrentUsage()
{
    LOCK(cs_LastBlockFile);

    uint64_t retval = 0;
    for (const CBlockFileInfo &file : vinfoBlockFile) {
        retval += file.nSize + file.nUndoSize;
    }
    return retval;
}

/* Prune a block file (modify associated database entries)*/
void PruneOneBlockFile(const int fileNumber)
{
    LOCK(cs_LastBlockFile);

    for (const auto& entry : mapBlockIndex) {
        CBlockIndex* pindex = entry.second;
        if (pindex->nFile == fileNumber) {
            pindex->nStatus &= ~BLOCK_HAVE_DATA;
            pindex->nStatus &= ~BLOCK_HAVE_UNDO;
            pindex->nFile = 0;
            pindex->nDataPos = 0;
            pindex->nUndoPos = 0;
            setDirtyBlockIndex.insert(pindex);

            // Prune from mapBlocksUnlinked -- any block we prune would have
            // to be downloaded again in order to consider its chain, at which
            // point it would be considered as a candidate for
            // mapBlocksUnlinked or setBlockIndexCandidates.
            std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> range = mapBlocksUnlinked.equal_range(pindex->pprev);
            while (range.first != range.second) {
                std::multimap<CBlockIndex *, CBlockIndex *>::iterator _it = range.first;
                range.first++;
                if (_it->second == pindex) {
                    mapBlocksUnlinked.erase(_it);
                }
            }
        }
    }

    vinfoBlockFile[fileNumber].SetNull();
    setDirtyFileInfo.insert(fileNumber);
}


void UnlinkPrunedFiles(const std::set<int>& setFilesToPrune)
{
    for (std::set<int>::iterator it = setFilesToPrune.begin(); it != setFilesToPrune.end(); ++it) {
        CDiskBlockPos pos(*it, 0);
        fs::remove(GetBlockPosFilename(pos, "blk"));
        fs::remove(GetBlockPosFilename(pos, "rev"));
        LogPrintf("Prune: %s deleted blk/rev (%05u)\n", __func__, *it);
    }
}

/* Calculate the block/rev files to delete based on height specified by user with RPC command pruneblockchain */
static void FindFilesToPruneManual(std::set<int>& setFilesToPrune, int nManualPruneHeight)
{
    assert(fPruneMode && nManualPruneHeight > 0);

    LOCK2(cs_main, cs_LastBlockFile);
    if (chainActive.Tip() == nullptr)
        return;

    // last block to prune is the lesser of (user-specified height, MIN_BLOCKS_TO_KEEP from the tip)
    unsigned int nLastBlockWeCanPrune = std::min((unsigned)nManualPruneHeight, chainActive.Tip()->nHeight - MIN_BLOCKS_TO_KEEP);
    int count=0;
    for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
        if (vinfoBlockFile[fileNumber].nSize == 0 || vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune)
            continue;
        PruneOneBlockFile(fileNumber);
        setFilesToPrune.insert(fileNumber);
        count++;
    }
    LogPrintf("Prune (Manual): prune_height=%d removed %d blk/rev pairs\n", nLastBlockWeCanPrune, count);
}

/* This function is called from the RPC code for pruneblockchain */
void PruneBlockFilesManual(int nManualPruneHeight)
{
    CValidationState state;
    const CChainParams& chainparams = Params();
    FlushStateToDisk(chainparams, state, FLUSH_STATE_NONE, nManualPruneHeight);
}

/**
 * Prune block and undo files (blk???.dat and undo???.dat) so that the disk space used is less than a user-defined target.
 * The user sets the target (in MB) on the command line or in config file.  This will be run on startup and whenever new
 * space is allocated in a block or undo file, staying below the target. Changing back to unpruned requires a reindex
 * (which in this case means the blockchain must be re-downloaded.)
 *
 * Pruning functions are called from FlushStateToDisk when the global fCheckForPruning flag has been set.
 * Block and undo files are deleted in lock-step (when blk00003.dat is deleted, so is rev00003.dat.)
 * Pruning cannot take place until the longest chain is at least a certain length (100000 on mainnet, 1000 on testnet, 1000 on regtest).
 * Pruning will never delete a block within a defined distance (currently 288) from the active chain's tip.
 * The block index is updated by unsetting HAVE_DATA and HAVE_UNDO for any blocks that were stored in the deleted files.
 * A db flag records the fact that at least some block files have been pruned.
 *
 * @param[out]   setFilesToPrune   The set of file indices that can be unlinked will be returned
 */
static void FindFilesToPrune(std::set<int>& setFilesToPrune, uint64_t nPruneAfterHeight)
{
    LOCK2(cs_main, cs_LastBlockFile);
    if (chainActive.Tip() == nullptr || nPruneTarget == 0) {
        return;
    }
    if ((uint64_t)chainActive.Tip()->nHeight <= nPruneAfterHeight) {
        return;
    }

    unsigned int nLastBlockWeCanPrune = chainActive.Tip()->nHeight - MIN_BLOCKS_TO_KEEP;
    uint64_t nCurrentUsage = CalculateCurrentUsage();
    // We don't check to prune until after we've allocated new space for files
    // So we should leave a buffer under our target to account for another allocation
    // before the next pruning.
    uint64_t nBuffer = BLOCKFILE_CHUNK_SIZE + UNDOFILE_CHUNK_SIZE;
    uint64_t nBytesToPrune;
    int count=0;

    if (nCurrentUsage + nBuffer >= nPruneTarget) {
        for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
            nBytesToPrune = vinfoBlockFile[fileNumber].nSize + vinfoBlockFile[fileNumber].nUndoSize;

            if (vinfoBlockFile[fileNumber].nSize == 0)
                continue;

            if (nCurrentUsage + nBuffer < nPruneTarget)  // are we below our target?
                break;

            // don't prune files that could have a block within MIN_BLOCKS_TO_KEEP of the main chain's tip but keep scanning
            if (vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune)
                continue;

            PruneOneBlockFile(fileNumber);
            // Queue up the files for removal
            setFilesToPrune.insert(fileNumber);
            nCurrentUsage -= nBytesToPrune;
            count++;
        }
    }

    LogPrint(BCLog::PRUNE, "Prune: target=%dMiB actual=%dMiB diff=%dMiB max_prune_height=%d removed %d blk/rev pairs\n",
           nPruneTarget/1024/1024, nCurrentUsage/1024/1024,
           ((int64_t)nPruneTarget - (int64_t)nCurrentUsage)/1024/1024,
           nLastBlockWeCanPrune, count);
}

bool CheckDiskSpace(uint64_t nAdditionalBytes)
{
    uint64_t nFreeBytesAvailable = fs::space(GetDataDir()).available;

    // Check for nMinDiskSpace bytes (currently 50MB)
    if (nFreeBytesAvailable < nMinDiskSpace + nAdditionalBytes)
        return AbortNode("Disk space is low!", _("Error: Disk space is low!"));

    return true;
}

static FILE* OpenDiskFile(const CDiskBlockPos &pos, const char *prefix, bool fReadOnly)
{
    if (pos.IsNull())
        return nullptr;
    fs::path path = GetBlockPosFilename(pos, prefix);
    fs::create_directories(path.parent_path());
    FILE* file = fsbridge::fopen(path, fReadOnly ? "rb": "rb+");
    if (!file && !fReadOnly)
        file = fsbridge::fopen(path, "wb+");
    if (!file) {
        LogPrintf("Unable to open file %s\n", path.string());
        return nullptr;
    }
    if (pos.nPos) {
        if (fseek(file, pos.nPos, SEEK_SET)) {
            LogPrintf("Unable to seek to position %u of %s\n", pos.nPos, path.string());
            fclose(file);
            return nullptr;
        }
    }
    return file;
}

FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly) {
    return OpenDiskFile(pos, "blk", fReadOnly);
}

/** Open an undo file (rev?????.dat) */
static FILE* OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly) {
    return OpenDiskFile(pos, "rev", fReadOnly);
}

fs::path GetBlockPosFilename(const CDiskBlockPos &pos, const char *prefix)
{
    return GetDataDir() / "blocks" / strprintf("%s%05u.dat", prefix, pos.nFile);
}

CBlockIndex * CChainState::InsertBlockIndex(const uint256& hash)
{
    if (hash.IsNull())
        return nullptr;

    // Return existing
    BlockMap::iterator mi = mapBlockIndex.find(hash);
    if (mi != mapBlockIndex.end())
        return (*mi).second;

    // Create new
    CBlockIndex* pindexNew = new CBlockIndex();
    mi = mapBlockIndex.insert(std::make_pair(hash, pindexNew)).first;
    pindexNew->phashBlock = &((*mi).first);

    return pindexNew;
}

bool CChainState::LoadBlockIndex(const Consensus::Params& consensus_params, CBlockTreeDB& blocktree)
{
    if (!blocktree.LoadBlockIndexGuts(consensus_params, [this](const uint256& hash){ return this->InsertBlockIndex(hash); }))
        return false;

    boost::this_thread::interruption_point();

    // Calculate nChainWork
    std::vector<std::pair<int, CBlockIndex*> > vSortedByHeight;
    vSortedByHeight.reserve(mapBlockIndex.size());
    for (const std::pair<uint256, CBlockIndex*>& item : mapBlockIndex)
    {
        CBlockIndex* pindex = item.second;
        vSortedByHeight.push_back(std::make_pair(pindex->nHeight, pindex));
    }
    sort(vSortedByHeight.begin(), vSortedByHeight.end());
    for (const std::pair<int, CBlockIndex*>& item : vSortedByHeight)
    {
        CBlockIndex* pindex = item.second;
        pindex->nChainWork = (pindex->pprev ? pindex->pprev->nChainWork : 0) + GetBlockProof(*pindex);
        pindex->nTimeMax = (pindex->pprev ? std::max(pindex->pprev->nTimeMax, pindex->nTime) : pindex->nTime);
        // We can link the chain of blocks for which we've received transactions at some point.
        // Pruned nodes may have deleted the block.
        if (pindex->nTx > 0) {
            if (pindex->pprev) {
                if (pindex->pprev->nChainTx) {
                    pindex->nChainTx = pindex->pprev->nChainTx + pindex->nTx;
                } else {
                    pindex->nChainTx = 0;
                    mapBlocksUnlinked.insert(std::make_pair(pindex->pprev, pindex));
                }
            } else {
                pindex->nChainTx = pindex->nTx;
            }
        }
        if (!(pindex->nStatus & BLOCK_FAILED_MASK) && pindex->pprev && (pindex->pprev->nStatus & BLOCK_FAILED_MASK)) {
            pindex->nStatus |= BLOCK_FAILED_CHILD;
            setDirtyBlockIndex.insert(pindex);
        }
        if (pindex->IsValid(BLOCK_VALID_TRANSACTIONS) && (pindex->nChainTx || pindex->pprev == nullptr))
            setBlockIndexCandidates.insert(pindex);
        if (pindex->nStatus & BLOCK_FAILED_MASK && (!pindexBestInvalid || pindex->nChainWork > pindexBestInvalid->nChainWork))
            pindexBestInvalid = pindex;
        if (pindex->pprev)
            pindex->BuildSkip();
        if (pindex->IsValid(BLOCK_VALID_TREE) && (pindexBestHeader == nullptr || CBlockIndexWorkComparator()(pindexBestHeader, pindex)))
            pindexBestHeader = pindex;
    }

    return true;
}

bool static LoadBlockIndexDB(const CChainParams& chainparams)
{
    if (!g_chainstate.LoadBlockIndex(chainparams.GetConsensus(), *pblocktree))
        return false;

    // Load block file info
    pblocktree->ReadLastBlockFile(nLastBlockFile);
    vinfoBlockFile.resize(nLastBlockFile + 1);
    LogPrintf("%s: last block file = %i\n", __func__, nLastBlockFile);
    for (int nFile = 0; nFile <= nLastBlockFile; nFile++) {
        pblocktree->ReadBlockFileInfo(nFile, vinfoBlockFile[nFile]);
    }
    LogPrintf("%s: last block file info: %s\n", __func__, vinfoBlockFile[nLastBlockFile].ToString());
    for (int nFile = nLastBlockFile + 1; true; nFile++) {
        CBlockFileInfo info;
        if (pblocktree->ReadBlockFileInfo(nFile, info)) {
            vinfoBlockFile.push_back(info);
        } else {
            break;
        }
    }

    // Check presence of blk files
    LogPrintf("Checking all blk files are present...\n");
    std::set<int> setBlkDataFiles;
    for (const std::pair<uint256, CBlockIndex*>& item : mapBlockIndex)
    {
        CBlockIndex* pindex = item.second;
        if (pindex->nStatus & BLOCK_HAVE_DATA) {
            setBlkDataFiles.insert(pindex->nFile);
        }
    }
    for (std::set<int>::iterator it = setBlkDataFiles.begin(); it != setBlkDataFiles.end(); it++)
    {
        CDiskBlockPos pos(*it, 0);
        if (CAutoFile(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION).IsNull()) {
            return false;
        }
    }

    // Check whether we have ever pruned block & undo files
    pblocktree->ReadFlag("prunedblockfiles", fHavePruned);
    if (fHavePruned)
        LogPrintf("LoadBlockIndexDB(): Block files have previously been pruned\n");

    // Check whether we need to continue reindexing
    bool fReindexing = false;
    pblocktree->ReadReindexing(fReindexing);
    if(fReindexing) fReindex = true;

    // Check whether we have a transaction index
    pblocktree->ReadFlag("txindex", fTxIndex);
    LogPrintf("%s: transaction index %s\n", __func__, fTxIndex ? "enabled" : "disabled");

    // Check whether we have an address index
    pblocktree->ReadFlag("addressindex", fAddressIndex);
    LogPrintf("%s: address index %s\n", __func__, fAddressIndex ? "enabled" : "disabled");

    // Check whether we have a timestamp index
    pblocktree->ReadFlag("timestampindex", fTimestampIndex);
    LogPrintf("%s: timestamp index %s\n", __func__, fTimestampIndex ? "enabled" : "disabled");

    // Check whether we have a spent index
    pblocktree->ReadFlag("spentindex", fSpentIndex);
    LogPrintf("%s: spent index %s\n", __func__, fSpentIndex ? "enabled" : "disabled");

    return true;
}

bool LoadChainTip(const CChainParams& chainparams)
{
    if (chainActive.Tip() && chainActive.Tip()->GetBlockHash() == pcoinsTip->GetBestBlock()) return true;

    if (pcoinsTip->GetBestBlock().IsNull() && mapBlockIndex.size() == 1) {
        // In case we just added the genesis block, connect it now, so
        // that we always have a chainActive.Tip() when we return.
        LogPrintf("%s: Connecting genesis block...\n", __func__);
        CValidationState state;
        if (!ActivateBestChain(state, chainparams)) {
            return false;
        }
    }

    // Load pointer to end of best chain
    BlockMap::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
    if (it == mapBlockIndex.end())
        return false;
    chainActive.SetTip(it->second);

    g_chainstate.PruneBlockIndexCandidates();

    LogPrintf("Loaded best chain: hashBestChain=%s height=%d date=%s progress=%f\n",
        chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(),
        DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
        GuessVerificationProgress(chainparams.TxData(), chainActive.Tip()));
    return true;
}

CVerifyDB::CVerifyDB()
{
    uiInterface.ShowProgress(_("Verifying blocks..."), 0, false);
}

CVerifyDB::~CVerifyDB()
{
    uiInterface.ShowProgress("", 100, false);
}

bool CVerifyDB::VerifyDB(const CChainParams& chainparams, CCoinsView *coinsview, int nCheckLevel, int nCheckDepth)
{
    LOCK(cs_main);
    if (chainActive.Tip() == nullptr || chainActive.Tip()->pprev == nullptr)
        return true;

    // Verify blocks in the best chain
    if (nCheckDepth <= 0 || nCheckDepth > chainActive.Height())
        nCheckDepth = chainActive.Height();
    nCheckLevel = std::max(0, std::min(4, nCheckLevel));
    LogPrintf("Verifying last %i blocks at level %i\n", nCheckDepth, nCheckLevel);
    CCoinsViewCache coins(coinsview);
    CBlockIndex* pindexState = chainActive.Tip();
    CBlockIndex* pindexFailure = nullptr;
    int nGoodTransactions = 0;
    CValidationState state;
    int reportDone = 0;
    LogPrintf("[0%%]...");
    for (CBlockIndex* pindex = chainActive.Tip(); pindex && pindex->pprev; pindex = pindex->pprev)
    {
        boost::this_thread::interruption_point();
        int percentageDone = std::max(1, std::min(99, (int)(((double)(chainActive.Height() - pindex->nHeight)) / (double)nCheckDepth * (nCheckLevel >= 4 ? 50 : 100))));
        if (reportDone < percentageDone/10) {
            // report every 10% step
            LogPrintf("[%d%%]...", percentageDone);
            reportDone = percentageDone/10;
        }
        uiInterface.ShowProgress(_("Verifying blocks..."), percentageDone, false);
        if (pindex->nHeight < chainActive.Height()-nCheckDepth)
            break;
        if (fPruneMode && !(pindex->nStatus & BLOCK_HAVE_DATA)) {
            // If pruning, only go back as far as we have data.
            LogPrintf("VerifyDB(): block verification stopping at height %d (pruning, no data)\n", pindex->nHeight);
            break;
        }
        CBlock block;
        // check level 0: read from disk
        if (!ReadBlockFromDisk(block, pindex, chainparams.GetConsensus()))
            return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
        // check level 1: verify block validity
        if (nCheckLevel >= 1 && !CheckBlock(block, state, chainparams.GetConsensus()))
            return error("%s: *** found bad block at %d, hash=%s (%s)\n", __func__,
                         pindex->nHeight, pindex->GetBlockHash().ToString(), FormatStateMessage(state));
        // check level 2: verify undo validity
        if (nCheckLevel >= 2 && pindex) {
            CBlockUndo undo;
            if (!pindex->GetUndoPos().IsNull()) {
                if (!UndoReadFromDisk(undo, pindex)) {
                    return error("VerifyDB(): *** found bad undo data at %d, hash=%s\n", pindex->nHeight, pindex->GetBlockHash().ToString());
                }
            }
        }
        // check level 3: check for inconsistencies during memory-only disconnect of tip blocks
        if (nCheckLevel >= 3 && pindex == pindexState && (coins.DynamicMemoryUsage() + pcoinsTip->DynamicMemoryUsage()) <= nCoinCacheUsage) {
            assert(coins.GetBestBlock() == pindex->GetBlockHash());
            DisconnectResult res = g_chainstate.DisconnectBlock(block, pindex, coins, true);
            if (res == DISCONNECT_FAILED) {
                return error("VerifyDB(): *** irrecoverable inconsistency in block data at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
            }
            pindexState = pindex->pprev;
            if (res == DISCONNECT_UNCLEAN) {
                nGoodTransactions = 0;
                pindexFailure = pindex;
            } else {
                nGoodTransactions += block.vtx.size();
            }
        }
        if (ShutdownRequested())
            return true;
    }
    if (pindexFailure)
        return error("VerifyDB(): *** coin database inconsistencies found (last %i blocks, %i good transactions before that)\n", chainActive.Height() - pindexFailure->nHeight + 1, nGoodTransactions);

    // check level 4: try reconnecting blocks
    if (nCheckLevel >= 4) {
        CBlockIndex *pindex = pindexState;
        while (pindex != chainActive.Tip()) {
            boost::this_thread::interruption_point();
            uiInterface.ShowProgress(_("Verifying blocks..."), std::max(1, std::min(99, 100 - (int)(((double)(chainActive.Height() - pindex->nHeight)) / (double)nCheckDepth * 50))), false);
            pindex = chainActive.Next(pindex);
            CBlock block;
            if (!ReadBlockFromDisk(block, pindex, chainparams.GetConsensus()))
                return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
            if (!g_chainstate.ConnectBlock(block, state, pindex, coins, chainparams))
                return error("VerifyDB(): *** found unconnectable block at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
        }
    }

    LogPrintf("[DONE].\n");
    LogPrintf("No coin database inconsistencies in last %i blocks (%i transactions)\n", chainActive.Height() - pindexState->nHeight, nGoodTransactions);

    return true;
}

/** Apply the effects of a block on the utxo cache, ignoring that it may already have been applied. */
bool CChainState::RollforwardBlock(const CBlockIndex* pindex, CCoinsViewCache& inputs, const CChainParams& params)
{
    // TODO: merge with ConnectBlock
    CBlock block;
    if (!ReadBlockFromDisk(block, pindex, params.GetConsensus())) {
        return error("ReplayBlock(): ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
    }

    for (const CTransactionRef& tx : block.vtx) {
        if (!tx->IsCoinBase()) {
            for (const CTxIn &txin : tx->vin) {
                inputs.SpendCoin(txin.prevout);
            }
        }
        // Pass check = true as every addition may be an overwrite.
        AddCoins(inputs, *tx, pindex->nHeight, true);
    }
    return true;
}

bool CChainState::ReplayBlocks(const CChainParams& params, CCoinsView* view)
{
    LOCK(cs_main);

    CCoinsViewCache cache(view);

    std::vector<uint256> hashHeads = view->GetHeadBlocks();
    if (hashHeads.empty()) return true; // We're already in a consistent state.
    if (hashHeads.size() != 2) return error("ReplayBlocks(): unknown inconsistent state");

    uiInterface.ShowProgress(_("Replaying blocks..."), 0, false);
    LogPrintf("Replaying blocks\n");

    const CBlockIndex* pindexOld = nullptr;  // Old tip during the interrupted flush.
    const CBlockIndex* pindexNew;            // New tip during the interrupted flush.
    const CBlockIndex* pindexFork = nullptr; // Latest block common to both the old and the new tip.

    if (mapBlockIndex.count(hashHeads[0]) == 0) {
        return error("ReplayBlocks(): reorganization to unknown block requested");
    }
    pindexNew = mapBlockIndex[hashHeads[0]];

    if (!hashHeads[1].IsNull()) { // The old tip is allowed to be 0, indicating it's the first flush.
        if (mapBlockIndex.count(hashHeads[1]) == 0) {
            return error("ReplayBlocks(): reorganization from unknown block requested");
        }
        pindexOld = mapBlockIndex[hashHeads[1]];
        pindexFork = LastCommonAncestor(pindexOld, pindexNew);
        assert(pindexFork != nullptr);
    }

    // Rollback along the old branch.
    while (pindexOld != pindexFork) {
        if (pindexOld->nHeight > 0) { // Never disconnect the genesis block.
            CBlock block;
            if (!ReadBlockFromDisk(block, pindexOld, params.GetConsensus())) {
                return error("RollbackBlock(): ReadBlockFromDisk() failed at %d, hash=%s", pindexOld->nHeight, pindexOld->GetBlockHash().ToString());
            }
            LogPrintf("Rolling back %s (%i)\n", pindexOld->GetBlockHash().ToString(), pindexOld->nHeight);
            DisconnectResult res = DisconnectBlock(block, pindexOld, cache);
            if (res == DISCONNECT_FAILED) {
                return error("RollbackBlock(): DisconnectBlock failed at %d, hash=%s", pindexOld->nHeight, pindexOld->GetBlockHash().ToString());
            }
            // If DISCONNECT_UNCLEAN is returned, it means a non-existing UTXO was deleted, or an existing UTXO was
            // overwritten. It corresponds to cases where the block-to-be-disconnect never had all its operations
            // applied to the UTXO set. However, as both writing a UTXO and deleting a UTXO are idempotent operations,
            // the result is still a version of the UTXO set with the effects of that block undone.
        }
        pindexOld = pindexOld->pprev;
    }

    // Roll forward from the forking point to the new tip.
    int nForkHeight = pindexFork ? pindexFork->nHeight : 0;
    for (int nHeight = nForkHeight + 1; nHeight <= pindexNew->nHeight; ++nHeight) {
        const CBlockIndex* pindex = pindexNew->GetAncestor(nHeight);
        LogPrintf("Rolling forward %s (%i)\n", pindex->GetBlockHash().ToString(), nHeight);
        if (!RollforwardBlock(pindex, cache, params)) return false;
    }

    cache.SetBestBlock(pindexNew->GetBlockHash());
    cache.Flush();
    uiInterface.ShowProgress("", 100, false);
    return true;
}

bool ReplayBlocks(const CChainParams& params, CCoinsView* view) {
    return g_chainstate.ReplayBlocks(params, view);
}

bool CChainState::RewindBlockIndex(const CChainParams& params)
{
    LOCK(cs_main);

    // Note that during -reindex-chainstate we are called with an empty chainActive!

    int nHeight = 1;
    while (nHeight <= chainActive.Height()) {
        if (IsWitnessEnabled(chainActive[nHeight - 1], params.GetConsensus()) && !(chainActive[nHeight]->nStatus & BLOCK_OPT_WITNESS)) {
            break;
        }
        nHeight++;
    }

    // nHeight is now the height of the first insufficiently-validated block, or tipheight + 1
    CValidationState state;
    CBlockIndex* pindex = chainActive.Tip();
    while (chainActive.Height() >= nHeight) {
        if (fPruneMode && !(chainActive.Tip()->nStatus & BLOCK_HAVE_DATA)) {
            // If pruning, don't try rewinding past the HAVE_DATA point;
            // since older blocks can't be served anyway, there's
            // no need to walk further, and trying to DisconnectTip()
            // will fail (and require a needless reindex/redownload
            // of the blockchain).
            break;
        }
        if (!DisconnectTip(state, params, nullptr)) {
            return error("RewindBlockIndex: unable to disconnect block at height %i", pindex->nHeight);
        }
        // Occasionally flush state to disk.
        if (!FlushStateToDisk(params, state, FLUSH_STATE_PERIODIC))
            return false;
    }

    // Reduce validity flag and have-data flags.
    // We do this after actual disconnecting, otherwise we'll end up writing the lack of data
    // to disk before writing the chainstate, resulting in a failure to continue if interrupted.
    for (const auto& entry : mapBlockIndex) {
        CBlockIndex* pindexIter = entry.second;

        // Note: If we encounter an insufficiently validated block that
        // is on chainActive, it must be because we are a pruning node, and
        // this block or some successor doesn't HAVE_DATA, so we were unable to
        // rewind all the way.  Blocks remaining on chainActive at this point
        // must not have their validity reduced.
        if (IsWitnessEnabled(pindexIter->pprev, params.GetConsensus()) && !(pindexIter->nStatus & BLOCK_OPT_WITNESS) && !chainActive.Contains(pindexIter)) {
            // Reduce validity
            pindexIter->nStatus = std::min<unsigned int>(pindexIter->nStatus & BLOCK_VALID_MASK, BLOCK_VALID_TREE) | (pindexIter->nStatus & ~BLOCK_VALID_MASK);
            // Remove have-data flags.
            pindexIter->nStatus &= ~(BLOCK_HAVE_DATA | BLOCK_HAVE_UNDO);
            // Remove storage location.
            pindexIter->nFile = 0;
            pindexIter->nDataPos = 0;
            pindexIter->nUndoPos = 0;
            // Remove various other things
            pindexIter->nTx = 0;
            pindexIter->nChainTx = 0;
            pindexIter->nSequenceId = 0;
            // Make sure it gets written.
            setDirtyBlockIndex.insert(pindexIter);
            // Update indexes
            setBlockIndexCandidates.erase(pindexIter);
            std::pair<std::multimap<CBlockIndex*, CBlockIndex*>::iterator, std::multimap<CBlockIndex*, CBlockIndex*>::iterator> ret = mapBlocksUnlinked.equal_range(pindexIter->pprev);
            while (ret.first != ret.second) {
                if (ret.first->second == pindexIter) {
                    mapBlocksUnlinked.erase(ret.first++);
                } else {
                    ++ret.first;
                }
            }
        } else if (pindexIter->IsValid(BLOCK_VALID_TRANSACTIONS) && pindexIter->nChainTx) {
            setBlockIndexCandidates.insert(pindexIter);
        }
    }

    if (chainActive.Tip() != nullptr) {
        // We can't prune block index candidates based on our tip if we have
        // no tip due to chainActive being empty!
        PruneBlockIndexCandidates();

        CheckBlockIndex(params.GetConsensus());
    }

    return true;
}

bool RewindBlockIndex(const CChainParams& params) {
    if (!g_chainstate.RewindBlockIndex(params)) {
        return false;
    }

    if (chainActive.Tip() != nullptr) {
        // FlushStateToDisk can possibly read chainActive. Be conservative
        // and skip it here, we're about to -reindex-chainstate anyway, so
        // it'll get called a bunch real soon.
        CValidationState state;
        if (!FlushStateToDisk(params, state, FLUSH_STATE_ALWAYS)) {
            return false;
        }
    }

    return true;
}

void CChainState::UnloadBlockIndex() {
    nBlockSequenceId = 1;
    g_failed_blocks.clear();
    setBlockIndexCandidates.clear();
}

// May NOT be used after any connections are up as much
// of the peer-processing logic assumes a consistent
// block index state
void UnloadBlockIndex()
{
    LOCK(cs_main);
    chainActive.SetTip(nullptr);
    pindexBestInvalid = nullptr;
    pindexBestHeader = nullptr;
    mempool.clear();
    mapBlocksUnlinked.clear();
    vinfoBlockFile.clear();
    nLastBlockFile = 0;
    setDirtyBlockIndex.clear();
    setDirtyFileInfo.clear();
    versionbitscache.Clear();
    for (int b = 0; b < VERSIONBITS_NUM_BITS; b++) {
        warningcache[b].clear();
    }

    for (BlockMap::value_type& entry : mapBlockIndex) {
        delete entry.second;
    }
    mapBlockIndex.clear();
    fHavePruned = false;

    g_chainstate.UnloadBlockIndex();
}

bool LoadBlockIndex(const CChainParams& chainparams)
{
    // Load block index from databases
    bool needs_init = fReindex;
    if (!fReindex) {
        bool ret = LoadBlockIndexDB(chainparams);
        if (!ret) return false;
        needs_init = mapBlockIndex.empty();
    }

    if (needs_init) {
        // Everything here is for *new* reindex/DBs. Thus, though
        // LoadBlockIndexDB may have set fReindex if we shut down
        // mid-reindex previously, we don't check fReindex and
        // instead only check it prior to LoadBlockIndexDB to set
        // needs_init.

        LogPrintf("Initializing databases...\n");
        // Use the provided setting for -txindex in the new database
        fTxIndex = gArgs.GetBoolArg("-txindex", DEFAULT_TXINDEX);
        pblocktree->WriteFlag("txindex", fTxIndex);

        // Use the provided setting for -addressindex in the new database
        fAddressIndex = gArgs.GetBoolArg("-addressindex", DEFAULT_ADDRESSINDEX);
        pblocktree->WriteFlag("addressindex", fAddressIndex);

        // Use the provided setting for -timestampindex in the new database
        fTimestampIndex = gArgs.GetBoolArg("-timestampindex", DEFAULT_TIMESTAMPINDEX);
        pblocktree->WriteFlag("timestampindex", fTimestampIndex);

        fSpentIndex = gArgs.GetBoolArg("-spentindex", DEFAULT_SPENTINDEX);
        pblocktree->WriteFlag("spentindex", fSpentIndex);
        fprintf(stderr,"fAddressIndex.%d/%d fSpentIndex.%d/%d\n",fAddressIndex,DEFAULT_ADDRESSINDEX,fSpentIndex,DEFAULT_SPENTINDEX);
    }
    return true;
}

bool CChainState::LoadGenesisBlock(const CChainParams& chainparams)
{
    LOCK(cs_main);

    // Check whether we're already initialized by checking for genesis in
    // mapBlockIndex. Note that we can't use chainActive here, since it is
    // set based on the coins db, not the block index db, which is the only
    // thing loaded at this point.
    if (mapBlockIndex.count(chainparams.GenesisBlock().GetHash()))
        return true;

    try {
        CBlock &block = const_cast<CBlock&>(chainparams.GenesisBlock());
        CDiskBlockPos blockPos = SaveBlockToDisk(block, 0, chainparams, nullptr);
        if (blockPos.IsNull())
            return error("%s: writing genesis block to disk failed", __func__);
        CBlockIndex *pindex = AddToBlockIndex(block);
        CValidationState state;
        if (!ReceivedBlockTransactions(block, state, pindex, blockPos, chainparams.GetConsensus()))
            return error("%s: genesis block not accepted", __func__);
    } catch (const std::runtime_error& e) {
        return error("%s: failed to write genesis block: %s", __func__, e.what());
    }

    return true;
}

bool LoadGenesisBlock(const CChainParams& chainparams)
{
    return g_chainstate.LoadGenesisBlock(chainparams);
}

bool LoadExternalBlockFile(const CChainParams& chainparams, FILE* fileIn, CDiskBlockPos *dbp)
{
    // Map of disk positions for blocks with unknown parent (only used for reindex)
    static std::multimap<uint256, CDiskBlockPos> mapBlocksUnknownParent;
    int64_t nStart = GetTimeMillis();

    int nLoaded = 0;
    try {
        // This takes over fileIn and calls fclose() on it in the CBufferedFile destructor
        CBufferedFile blkdat(fileIn, 2*MAX_BLOCK_SERIALIZED_SIZE, MAX_BLOCK_SERIALIZED_SIZE+8, SER_DISK, CLIENT_VERSION);
        uint64_t nRewind = blkdat.GetPos();
        while (!blkdat.eof()) {
            boost::this_thread::interruption_point();

            blkdat.SetPos(nRewind);
            nRewind++; // start one byte further next time, in case of failure
            blkdat.SetLimit(); // remove former limit
            unsigned int nSize = 0;
            try {
                // locate a header
                unsigned char buf[CMessageHeader::MESSAGE_START_SIZE];
                blkdat.FindByte(chainparams.MessageStart()[0]);
                nRewind = blkdat.GetPos()+1;
                blkdat >> FLATDATA(buf);
                if (memcmp(buf, chainparams.MessageStart(), CMessageHeader::MESSAGE_START_SIZE))
                    continue;
                // read size
                blkdat >> nSize;
                if (nSize < 80 || nSize > MAX_BLOCK_SERIALIZED_SIZE)
                    continue;
            } catch (const std::exception&) {
                // no valid block header found; don't complain
                break;
            }
            try {
                // read block
                uint64_t nBlockPos = blkdat.GetPos();
                if (dbp)
                    dbp->nPos = nBlockPos;
                blkdat.SetLimit(nBlockPos + nSize);
                blkdat.SetPos(nBlockPos);
                std::shared_ptr<CBlock> pblock = std::make_shared<CBlock>();
                CBlock& block = *pblock;
                blkdat >> block;
                nRewind = blkdat.GetPos();

                // detect out of order blocks, and store them for later
                uint256 hash = block.GetHash();
                if (hash != chainparams.GetConsensus().hashGenesisBlock && mapBlockIndex.find(block.hashPrevBlock) == mapBlockIndex.end()) {
                    LogPrint(BCLog::REINDEX, "%s: Out of order block %s, parent %s not known\n", __func__, hash.ToString(),
                            block.hashPrevBlock.ToString());
                    if (dbp)
                        mapBlocksUnknownParent.insert(std::make_pair(block.hashPrevBlock, *dbp));
                    continue;
                }

                // process in case the block isn't known yet
                if (mapBlockIndex.count(hash) == 0 || (mapBlockIndex[hash]->nStatus & BLOCK_HAVE_DATA) == 0) {
                    LOCK(cs_main);
                    CValidationState state;
                    if (g_chainstate.AcceptBlock(pblock, state, chainparams, nullptr, true, dbp, nullptr))
                        nLoaded++;
                    if (state.IsError())
                        break;
                } else if (hash != chainparams.GetConsensus().hashGenesisBlock && mapBlockIndex[hash]->nHeight % 1000 == 0) {
                    LogPrint(BCLog::REINDEX, "Block Import: already had block %s at height %d\n", hash.ToString(), mapBlockIndex[hash]->nHeight);
                }

                // Activate the genesis block so normal node progress can continue
                if (hash == chainparams.GetConsensus().hashGenesisBlock) {
                    CValidationState state;
                    if (!ActivateBestChain(state, chainparams)) {
                        break;
                    }
                }

                NotifyHeaderTip();

                // Recursively process earlier encountered successors of this block
                std::deque<uint256> queue;
                queue.push_back(hash);
                while (!queue.empty()) {
                    uint256 head = queue.front();
                    queue.pop_front();
                    std::pair<std::multimap<uint256, CDiskBlockPos>::iterator, std::multimap<uint256, CDiskBlockPos>::iterator> range = mapBlocksUnknownParent.equal_range(head);
                    while (range.first != range.second) {
                        std::multimap<uint256, CDiskBlockPos>::iterator it = range.first;
                        std::shared_ptr<CBlock> pblockrecursive = std::make_shared<CBlock>();
                        if (ReadBlockFromDisk(*pblockrecursive, it->second, chainparams.GetConsensus()))
                        {
                            LogPrint(BCLog::REINDEX, "%s: Processing out of order child %s of %s\n", __func__, pblockrecursive->GetHash().ToString(),
                                    head.ToString());
                            LOCK(cs_main);
                            CValidationState dummy;
                            if (g_chainstate.AcceptBlock(pblockrecursive, dummy, chainparams, nullptr, true, &it->second, nullptr))
                            {
                                nLoaded++;
                                queue.push_back(pblockrecursive->GetHash());
                            }
                        }
                        range.first++;
                        mapBlocksUnknownParent.erase(it);
                        NotifyHeaderTip();
                    }
                }
            } catch (const std::exception& e) {
                LogPrintf("%s: Deserialize or I/O error - %s\n", __func__, e.what());
            }
        }
    } catch (const std::runtime_error& e) {
        AbortNode(std::string("System error: ") + e.what());
    }
    if (nLoaded > 0)
        LogPrintf("Loaded %i blocks from external file in %dms\n", nLoaded, GetTimeMillis() - nStart);
    return nLoaded > 0;
}

void CChainState::CheckBlockIndex(const Consensus::Params& consensusParams)
{
    if (!fCheckBlockIndex) {
        return;
    }

    LOCK(cs_main);

    // During a reindex, we read the genesis block and call CheckBlockIndex before ActivateBestChain,
    // so we have the genesis block in mapBlockIndex but no active chain.  (A few of the tests when
    // iterating the block tree require that chainActive has been initialized.)
    if (chainActive.Height() < 0) {
        assert(mapBlockIndex.size() <= 1);
        return;
    }

    // Build forward-pointing map of the entire block tree.
    std::multimap<CBlockIndex*,CBlockIndex*> forward;
    for (auto& entry : mapBlockIndex) {
        forward.insert(std::make_pair(entry.second->pprev, entry.second));
    }

    assert(forward.size() == mapBlockIndex.size());

    std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeGenesis = forward.equal_range(nullptr);
    CBlockIndex *pindex = rangeGenesis.first->second;
    rangeGenesis.first++;
    assert(rangeGenesis.first == rangeGenesis.second); // There is only one index entry with parent nullptr.

    // Iterate over the entire block tree, using depth-first search.
    // Along the way, remember whether there are blocks on the path from genesis
    // block being explored which are the first to have certain properties.
    size_t nNodes = 0;
    int nHeight = 0;
    CBlockIndex* pindexFirstInvalid = nullptr; // Oldest ancestor of pindex which is invalid.
    CBlockIndex* pindexFirstMissing = nullptr; // Oldest ancestor of pindex which does not have BLOCK_HAVE_DATA.
    CBlockIndex* pindexFirstNeverProcessed = nullptr; // Oldest ancestor of pindex for which nTx == 0.
    CBlockIndex* pindexFirstNotTreeValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE (regardless of being valid or not).
    CBlockIndex* pindexFirstNotTransactionsValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS (regardless of being valid or not).
    CBlockIndex* pindexFirstNotChainValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN (regardless of being valid or not).
    CBlockIndex* pindexFirstNotScriptsValid = nullptr; // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS (regardless of being valid or not).
    while (pindex != nullptr) {
        nNodes++;
        if (pindexFirstInvalid == nullptr && pindex->nStatus & BLOCK_FAILED_VALID) pindexFirstInvalid = pindex;
        if (pindexFirstMissing == nullptr && !(pindex->nStatus & BLOCK_HAVE_DATA)) pindexFirstMissing = pindex;
        if (pindexFirstNeverProcessed == nullptr && pindex->nTx == 0) pindexFirstNeverProcessed = pindex;
        if (pindex->pprev != nullptr && pindexFirstNotTreeValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TREE) pindexFirstNotTreeValid = pindex;
        if (pindex->pprev != nullptr && pindexFirstNotTransactionsValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TRANSACTIONS) pindexFirstNotTransactionsValid = pindex;
        if (pindex->pprev != nullptr && pindexFirstNotChainValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_CHAIN) pindexFirstNotChainValid = pindex;
        if (pindex->pprev != nullptr && pindexFirstNotScriptsValid == nullptr && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS) pindexFirstNotScriptsValid = pindex;

        // Begin: actual consistency checks.
        if (pindex->pprev == nullptr) {
            // Genesis block checks.
            assert(pindex->GetBlockHash() == consensusParams.hashGenesisBlock); // Genesis block's hash must match.
            assert(pindex == chainActive.Genesis()); // The current active chain's genesis block must be this block.
        }
        if (pindex->nChainTx == 0) assert(pindex->nSequenceId <= 0);  // nSequenceId can't be set positive for blocks that aren't linked (negative is used for preciousblock)
        // VALID_TRANSACTIONS is equivalent to nTx > 0 for all nodes (whether or not pruning has occurred).
        // HAVE_DATA is only equivalent to nTx > 0 (or VALID_TRANSACTIONS) if no pruning has occurred.
        if (!fHavePruned) {
            // If we've never pruned, then HAVE_DATA should be equivalent to nTx > 0
            assert(!(pindex->nStatus & BLOCK_HAVE_DATA) == (pindex->nTx == 0));
            assert(pindexFirstMissing == pindexFirstNeverProcessed);
        } else {
            // If we have pruned, then we can only say that HAVE_DATA implies nTx > 0
            if (pindex->nStatus & BLOCK_HAVE_DATA) assert(pindex->nTx > 0);
        }
        if (pindex->nStatus & BLOCK_HAVE_UNDO) assert(pindex->nStatus & BLOCK_HAVE_DATA);
        assert(((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TRANSACTIONS) == (pindex->nTx > 0)); // This is pruning-independent.
        // All parents having had data (at some point) is equivalent to all parents being VALID_TRANSACTIONS, which is equivalent to nChainTx being set.
        assert((pindexFirstNeverProcessed != nullptr) == (pindex->nChainTx == 0)); // nChainTx != 0 is used to signal that all parent blocks have been processed (but may have been pruned).
        assert((pindexFirstNotTransactionsValid != nullptr) == (pindex->nChainTx == 0));
        assert(pindex->nHeight == nHeight); // nHeight must be consistent.
        assert(pindex->pprev == nullptr || pindex->nChainWork >= pindex->pprev->nChainWork); // For every block except the genesis block, the chainwork must be larger than the parent's.
        assert(nHeight < 2 || (pindex->pskip && (pindex->pskip->nHeight < nHeight))); // The pskip pointer must point back for all but the first 2 blocks.
        assert(pindexFirstNotTreeValid == nullptr); // All mapBlockIndex entries must at least be TREE valid
        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE) assert(pindexFirstNotTreeValid == nullptr); // TREE valid implies all parents are TREE valid
        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_CHAIN) assert(pindexFirstNotChainValid == nullptr); // CHAIN valid implies all parents are CHAIN valid
        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_SCRIPTS) assert(pindexFirstNotScriptsValid == nullptr); // SCRIPTS valid implies all parents are SCRIPTS valid
        if (pindexFirstInvalid == nullptr) {
            // Checks for not-invalid blocks.
            assert((pindex->nStatus & BLOCK_FAILED_MASK) == 0); // The failed mask cannot be set for blocks without invalid parents.
        }
        if (!CBlockIndexWorkComparator()(pindex, chainActive.Tip()) && pindexFirstNeverProcessed == nullptr) {
            if (pindexFirstInvalid == nullptr) {
                // If this block sorts at least as good as the current tip and
                // is valid and we have all data for its parents, it must be in
                // setBlockIndexCandidates.  chainActive.Tip() must also be there
                // even if some data has been pruned.
                if (pindexFirstMissing == nullptr || pindex == chainActive.Tip()) {
                    assert(setBlockIndexCandidates.count(pindex));
                }
                // If some parent is missing, then it could be that this block was in
                // setBlockIndexCandidates but had to be removed because of the missing data.
                // In this case it must be in mapBlocksUnlinked -- see test below.
            }
        } else { // If this block sorts worse than the current tip or some ancestor's block has never been seen, it cannot be in setBlockIndexCandidates.
            assert(setBlockIndexCandidates.count(pindex) == 0);
        }
        // Check whether this block is in mapBlocksUnlinked.
        std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeUnlinked = mapBlocksUnlinked.equal_range(pindex->pprev);
        bool foundInUnlinked = false;
        while (rangeUnlinked.first != rangeUnlinked.second) {
            assert(rangeUnlinked.first->first == pindex->pprev);
            if (rangeUnlinked.first->second == pindex) {
                foundInUnlinked = true;
                break;
            }
            rangeUnlinked.first++;
        }
        if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed != nullptr && pindexFirstInvalid == nullptr) {
            // If this block has block data available, some parent was never received, and has no invalid parents, it must be in mapBlocksUnlinked.
            assert(foundInUnlinked);
        }
        if (!(pindex->nStatus & BLOCK_HAVE_DATA)) assert(!foundInUnlinked); // Can't be in mapBlocksUnlinked if we don't HAVE_DATA
        if (pindexFirstMissing == nullptr) assert(!foundInUnlinked); // We aren't missing data for any parent -- cannot be in mapBlocksUnlinked.
        if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed == nullptr && pindexFirstMissing != nullptr) {
            // We HAVE_DATA for this block, have received data for all parents at some point, but we're currently missing data for some parent.
            assert(fHavePruned); // We must have pruned.
            // This block may have entered mapBlocksUnlinked if:
            //  - it has a descendant that at some point had more work than the
            //    tip, and
            //  - we tried switching to that descendant but were missing
            //    data for some intermediate block between chainActive and the
            //    tip.
            // So if this block is itself better than chainActive.Tip() and it wasn't in
            // setBlockIndexCandidates, then it must be in mapBlocksUnlinked.
            if (!CBlockIndexWorkComparator()(pindex, chainActive.Tip()) && setBlockIndexCandidates.count(pindex) == 0) {
                if (pindexFirstInvalid == nullptr) {
                    assert(foundInUnlinked);
                }
            }
        }
        // assert(pindex->GetBlockHash() == pindex->GetBlockHeader().GetHash()); // Perhaps too slow
        // End: actual consistency checks.

        // Try descending into the first subnode.
        std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> range = forward.equal_range(pindex);
        if (range.first != range.second) {
            // A subnode was found.
            pindex = range.first->second;
            nHeight++;
            continue;
        }
        // This is a leaf node.
        // Move upwards until we reach a node of which we have not yet visited the last child.
        while (pindex) {
            // We are going to either move to a parent or a sibling of pindex.
            // If pindex was the first with a certain property, unset the corresponding variable.
            if (pindex == pindexFirstInvalid) pindexFirstInvalid = nullptr;
            if (pindex == pindexFirstMissing) pindexFirstMissing = nullptr;
            if (pindex == pindexFirstNeverProcessed) pindexFirstNeverProcessed = nullptr;
            if (pindex == pindexFirstNotTreeValid) pindexFirstNotTreeValid = nullptr;
            if (pindex == pindexFirstNotTransactionsValid) pindexFirstNotTransactionsValid = nullptr;
            if (pindex == pindexFirstNotChainValid) pindexFirstNotChainValid = nullptr;
            if (pindex == pindexFirstNotScriptsValid) pindexFirstNotScriptsValid = nullptr;
            // Find our parent.
            CBlockIndex* pindexPar = pindex->pprev;
            // Find which child we just visited.
            std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangePar = forward.equal_range(pindexPar);
            while (rangePar.first->second != pindex) {
                assert(rangePar.first != rangePar.second); // Our parent must have at least the node we're coming from as child.
                rangePar.first++;
            }
            // Proceed to the next one.
            rangePar.first++;
            if (rangePar.first != rangePar.second) {
                // Move to the sibling.
                pindex = rangePar.first->second;
                break;
            } else {
                // Move up further.
                pindex = pindexPar;
                nHeight--;
                continue;
            }
        }
    }

    // Check that we actually traversed the entire map.
    assert(nNodes == forward.size());
}

std::string CBlockFileInfo::ToString() const
{
    return strprintf("CBlockFileInfo(blocks=%u, size=%u, heights=%u...%u, time=%s...%s)", nBlocks, nSize, nHeightFirst, nHeightLast, DateTimeStrFormat("%Y-%m-%d", nTimeFirst), DateTimeStrFormat("%Y-%m-%d", nTimeLast));
}

CBlockFileInfo* GetBlockFileInfo(size_t n)
{
    LOCK(cs_LastBlockFile);

    return &vinfoBlockFile.at(n);
}

ThresholdState VersionBitsTipState(const Consensus::Params& params, Consensus::DeploymentPos pos)
{
    LOCK(cs_main);
    return VersionBitsState(chainActive.Tip(), params, pos, versionbitscache);
}

BIP9Stats VersionBitsTipStatistics(const Consensus::Params& params, Consensus::DeploymentPos pos)
{
    LOCK(cs_main);
    return VersionBitsStatistics(chainActive.Tip(), params, pos);
}

int VersionBitsTipStateSinceHeight(const Consensus::Params& params, Consensus::DeploymentPos pos)
{
    LOCK(cs_main);
    return VersionBitsStateSinceHeight(chainActive.Tip(), params, pos, versionbitscache);
}

static const uint64_t MEMPOOL_DUMP_VERSION = 1;

bool LoadMempool(void)
{
    const CChainParams& chainparams = Params();
    int64_t nExpiryTimeout = gArgs.GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60;
    FILE* filestr = fsbridge::fopen(GetDataDir() / "mempool.dat", "rb");
    CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
    if (file.IsNull()) {
        LogPrintf("Failed to open mempool file from disk. Continuing anyway.\n");
        return false;
    }

    int64_t count = 0;
    int64_t expired = 0;
    int64_t failed = 0;
    int64_t already_there = 0;
    int64_t nNow = GetTime();

    try {
        uint64_t version;
        file >> version;
        if (version != MEMPOOL_DUMP_VERSION) {
            return false;
        }
        uint64_t num;
        file >> num;
        while (num--) {
            CTransactionRef tx;
            int64_t nTime;
            int64_t nFeeDelta;
            file >> tx;
            file >> nTime;
            file >> nFeeDelta;

            CAmount amountdelta = nFeeDelta;
            if (amountdelta) {
                mempool.PrioritiseTransaction(tx->GetHash(), amountdelta);
            }
            CValidationState state;
            if (nTime + nExpiryTimeout > nNow) {
                LOCK(cs_main);
                AcceptToMemoryPoolWithTime(chainparams, mempool, state, tx, nullptr /* pfMissingInputs */, nTime,
                                           nullptr /* plTxnReplaced */, false /* bypass_limits */, 0 /* nAbsurdFee */);
                if (state.IsValid()) {
                    ++count;
                } else {
                    // mempool may contain the transaction already, e.g. from
                    // wallet(s) having loaded it while we were processing
                    // mempool transactions; consider these as valid, instead of
                    // failed, but mark them as 'already there'
                    if (mempool.exists(tx->GetHash())) {
                        ++already_there;
                    } else {
                        ++failed;
                    }
                }
            } else {
                ++expired;
            }
            if (ShutdownRequested())
                return false;
        }
        std::map<uint256, CAmount> mapDeltas;
        file >> mapDeltas;

        for (const auto& i : mapDeltas) {
            mempool.PrioritiseTransaction(i.first, i.second);
        }
    } catch (const std::exception& e) {
        LogPrintf("Failed to deserialize mempool data on disk: %s. Continuing anyway.\n", e.what());
        return false;
    }

    LogPrintf("Imported mempool transactions from disk: %i succeeded, %i failed, %i expired, %i already there\n", count, failed, expired, already_there);
    return true;
}

bool DumpMempool(void)
{
    int64_t start = GetTimeMicros();

    std::map<uint256, CAmount> mapDeltas;
    std::vector<TxMempoolInfo> vinfo;

    {
        LOCK(mempool.cs);
        for (const auto &i : mempool.mapDeltas) {
            mapDeltas[i.first] = i.second;
        }
        vinfo = mempool.infoAll();
    }

    int64_t mid = GetTimeMicros();

    try {
        FILE* filestr = fsbridge::fopen(GetDataDir() / "mempool.dat.new", "wb");
        if (!filestr) {
            return false;
        }

        CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);

        uint64_t version = MEMPOOL_DUMP_VERSION;
        file << version;

        file << (uint64_t)vinfo.size();
        for (const auto& i : vinfo) {
            file << *(i.tx);
            file << (int64_t)i.nTime;
            file << (int64_t)i.nFeeDelta;
            mapDeltas.erase(i.tx->GetHash());
        }

        file << mapDeltas;
        FileCommit(file.Get());
        file.fclose();
        RenameOver(GetDataDir() / "mempool.dat.new", GetDataDir() / "mempool.dat");
        int64_t last = GetTimeMicros();
        LogPrintf("Dumped mempool: %gs to copy, %gs to dump\n", (mid-start)*MICRO, (last-mid)*MICRO);
    } catch (const std::exception& e) {
        LogPrintf("Failed to dump mempool: %s. Continuing anyway.\n", e.what());
        return false;
    }
    return true;
}

//! Guess how far we are in the verification process at the given block index
double GuessVerificationProgress(const ChainTxData& data, const CBlockIndex *pindex) {
    if (pindex == nullptr)
        return 0.0;

    int64_t nNow = time(nullptr);

    double fTxTotal;

    if (pindex->nChainTx <= data.nTxCount) {
        fTxTotal = data.nTxCount + (nNow - data.nTime) * data.dTxRate;
    } else {
        fTxTotal = pindex->nChainTx + (nNow - pindex->GetBlockTime()) * data.dTxRate;
    }

    return pindex->nChainTx / fTxTotal;
}

class CMainCleanup
{
public:
    CMainCleanup() {}
    ~CMainCleanup() {
        // block headers
        BlockMap::iterator it1 = mapBlockIndex.begin();
        for (; it1 != mapBlockIndex.end(); it1++)
            delete (*it1).second;
        mapBlockIndex.clear();
    }
} instance_of_cmaincleanup;

CBlockIndex *getblockindex(uint256 hash)
{
    BlockMap::const_iterator it = mapBlockIndex.find(hash);
    return((it != mapBlockIndex.end()) ? it->second : NULL);
}

uint32_t chainactive_timestamp()
{
    if ( chainActive.LastTip() != 0 )
        return((uint32_t)chainActive.LastTip()->GetBlockTime());
    else return(0);
}

int32_t currentheight()
{
    if ( chainActive.LastTip() != 0 )
        return((int32_t)chainActive.LastTip()->GetHeight());
    else return(0);
}

int32_t SMARTUSD_LONGESTCHAIN;
int32_t longestchain()
{
    static int32_t depth;
    int32_t ht,n=0,num=0,maxheight=0,height = 0;
    if ( depth < 0 )
        depth = 0;
    if ( depth == 0 )
    {
        depth++;
        std::vector<CNodeStats> vstats;
        {
            //LOCK(cs_main);
            g_connman->CopyNodeStats(vstats);
        }
        BOOST_FOREACH(const CNodeStats& stats, vstats)
        {
            //fprintf(stderr,"longestchain iter.%d\n",n);
            CNodeStateStats statestats;
            bool fStateStats = GetNodeStateStats(stats.nodeid,statestats);
            if ( statestats.nSyncHeight < 0 )
                continue;
            ht = 0;
            if ( stats.nStartingHeight > ht )
                ht = stats.nStartingHeight;
            if ( statestats.nSyncHeight > ht )
                ht = statestats.nSyncHeight;
            if ( statestats.nCommonHeight > ht )
                ht = statestats.nCommonHeight;
            if ( maxheight == 0 || ht > maxheight*1.01 )
                maxheight = ht, num = 1;
            else if ( ht > maxheight*0.99 )
                num++;
            if ( ht > height )
                height = ht;
        }
        depth--;
        if ( num > (n >> 1) )
        {
            if ( 0 && height != SMARTUSD_LONGESTCHAIN )
                fprintf(stderr,"set %s SMARTUSD_LONGESTCHAIN <- %d\n",ASSETCHAINS_SYMBOL,height);
            SMARTUSD_LONGESTCHAIN = height;
            return(height);
        }
        SMARTUSD_LONGESTCHAIN = 0;
    }
    return(SMARTUSD_LONGESTCHAIN);
}

int32_t smartusd_nextheight()
{
    CBlockIndex *pindex; int32_t ht;
    if ( (pindex= chainActive.LastTip()) != 0 && (ht= pindex->GetHeight()) > 0 )
        return(ht+1);
    else return(longestchain() + 1);
}

int32_t _smartusd_heightpricebits(uint64_t *seedp,uint32_t *heightbits,CBlock *block)
{
    CTransaction tx; int32_t numvouts; std::vector<uint8_t> vopret;
    tx = *(block->vtx[0].get());
    numvouts = (int32_t)tx.vout.size();
    GetOpReturnData(tx.vout[numvouts-1].scriptPubKey,vopret);
    if ( vopret.size() >= PRICES_SIZEBIT0 )
    {
        if ( seedp != 0 )
            memcpy(seedp,&block->hashMerkleRoot,sizeof(*seedp));
        memcpy(heightbits,vopret.data(),vopret.size());
        return((int32_t)(vopret.size()/sizeof(uint32_t)));
    }
    return(-1);
}

CBlockIndex *smartusd_chainactive(int32_t height)
{
    if ( chainActive.LastTip() != 0 )
    {
        if ( height <= chainActive.LastTip()->GetHeight() )
            return(chainActive[height]);
        // else LogPrintf("komodo_chainactive height %d > active.%d\n",height,chainActive.LastTip()->GetHeight());
    }
    //LogPrintf("komodo_chainactive null chainActive.LastTip() height %d\n",height);
    return(0);
}

int32_t smartusd_blockload(CBlock& block,CBlockIndex *pindex)
{
    block.SetNull();
    // Open history file to read
    CAutoFile filein(OpenBlockFile(pindex->GetBlockPos(),true),SER_DISK,CLIENT_VERSION);
    if (filein.IsNull())
        return(-1);
    // Read block
    try { filein >> block; }
    catch (const std::exception& e)
    {
        LogPrintf("readblockfromdisk err B\n");
        return(-1);
    }
    return(0);
}

int32_t smartusd_heightpricebits(uint64_t *seedp,uint32_t *heightbits,int32_t nHeight)
{
    CBlockIndex *pindex; CBlock block;
    if ( seedp != 0 )
        *seedp = 0;
    if ( (pindex= smartusd_chainactive(nHeight)) != 0 )
    {
        if ( smartusd_blockload(block,pindex) == 0 )
        {
            return(_smartusd_heightpricebits(seedp,heightbits,&block));
        }
    }
    LogPrintf("couldnt get pricebits for %d\n",nHeight);
    return(-1);
}

char *smartusd_pricename(char *name, size_t name_size, int32_t ind)
{
    strlcpy(name,"error",name_size);
    return(0);
}

// returns price value which is in a 10% interval for more than 50% points for the preceding 24 hours
int64_t smartusd_pricecorrelated(uint64_t seed,int32_t ind,uint32_t *rawprices,int32_t rawskip,uint32_t *nonzprices,int32_t smoothwidth)
{
    int32_t i,j,k,n,iter,correlation,maxcorrelation=0; int64_t firstprice,price,sum,den,mult,refprice,lowprice,highprice;
    if ( PRICES_DAYWINDOW < 2 || ind >= SMARTUSD_MAXPRICES )
        return(-1);
    mult = smartusd_pricemult(ind);
    if ( nonzprices != 0 )
        memset(nonzprices,0,sizeof(*nonzprices)*PRICES_DAYWINDOW);
    //for (i=0; i<PRICES_DAYWINDOW; i++)
    //    LogPrintf("%u ",rawprices[i*rawskip]);
    //LogPrintf("ind.%d\n",ind);
    for (iter=0; iter<PRICES_DAYWINDOW; iter++)
    {
        correlation = 0;
        i = (iter + seed) % PRICES_DAYWINDOW;
        refprice = rawprices[i*rawskip];
        highprice = (refprice * (COIN + PRICES_ERRORRATE*5)) / COIN;
        lowprice = (refprice * (COIN - PRICES_ERRORRATE*5)) / COIN;
        if ( highprice == refprice )
            highprice++;
        if ( lowprice == refprice )
            lowprice--;
        sum = 0;
        //LogPrintf("firsti.%d: ",i);
        for (j=0; j<PRICES_DAYWINDOW; j++,i++)
        {
            if ( i >= PRICES_DAYWINDOW )
                i = 0;
            if ( (price= rawprices[i*rawskip]) == 0 )
            {
                LogPrintf("null rawprice.[%d]\n",i);
                return(-1);
            }
            if ( price >= lowprice && price <= highprice )
            {
                //LogPrintf("%.1f ",(double)price/10000);
                sum += price;
                correlation++;
                if ( correlation > (PRICES_DAYWINDOW>>1) )
                {
                    if ( nonzprices == 0 )
                        return(refprice * mult);
                    //LogPrintf("-> %.4f\n",(double)sum*mult/correlation);
                    //return(sum*mult/correlation);
                    n = 0;
                    i = (iter + seed) % PRICES_DAYWINDOW;
                    for (k=0; k<PRICES_DAYWINDOW; k++,i++)
                    {
                        if ( i >= PRICES_DAYWINDOW )
                            i = 0;
                        if ( n > (PRICES_DAYWINDOW>>1) )
                            nonzprices[i] = 0;
                        else
                        {
                            price = rawprices[i*rawskip];
                            if ( price < lowprice || price > highprice )
                                nonzprices[i] = 0;
                            else
                            {
                                nonzprices[i] = price;
                                //LogPrintf("(%d %u) ",i,rawprices[i*rawskip]);
                                n++;
                            }
                        }
                    }
                    //LogPrintf("ind.%d iter.%d j.%d i.%d n.%d correlation.%d ref %llu -> %llu\n",ind,iter,j,i,n,correlation,(long long)refprice,(long long)sum/correlation);
                    if ( n != correlation )
                        return(-1);
                    sum = den = n = 0;
                    for (i=0; i<PRICES_DAYWINDOW; i++)
                        if ( nonzprices[i] != 0 )
                            break;
                    firstprice = nonzprices[i];
                    //LogPrintf("firsti.%d: ",i);
                    for (i=0; i<PRICES_DAYWINDOW; i++)
                    {
                        if ( (price= nonzprices[i]) != 0 )
                        {
                            den += (PRICES_DAYWINDOW - i);
                            sum += ((PRICES_DAYWINDOW - i) * (price + firstprice*4)) / 5;
                            n++;
                        }
                    }
                    if ( n != correlation || sum == 0 || den == 0 )
                    {
                        LogPrintf("seed.%llu n.%d vs correlation.%d sum %llu, den %llu\n",(long long)seed,n,correlation,(long long)sum,(long long)den);
                        return(-1);
                    }
                    //LogPrintf("firstprice.%llu weighted -> %.8f\n",(long long)firstprice,((double)(sum*mult) / den) / COIN);
                    return((sum * mult) / den);
                }
            }
        }
        if ( correlation > maxcorrelation )
            maxcorrelation = correlation;
    }
    LogPrintf("ind.%d iter.%d maxcorrelation.%d ref.%llu high.%llu low.%llu\n",ind,iter,maxcorrelation,(long long)refprice,(long long)highprice,(long long)lowprice);
    return(0);
}

int64_t smartusd_pricemult(int32_t ind)
{
    return(0);
}

// http://www.holoborodko.com/pavel/numerical-methods/noise-robust-smoothing-filter/
//const int64_t coeffs[7] = { -2, 0, 18, 32, 18, 0, -2 };
static int cmp_llu(const void *a, const void*b)
{
    if(*(int64_t *)a < *(int64_t *)b) return -1;
    else if(*(int64_t *)a > *(int64_t *)b) return 1;
    else if ( (uint64_t)a < (uint64_t)b ) // jl777 prevent nondeterminism
        return(-1);
    else return(1);
}

static int revcmp_llu(const void *a, const void*b)
{
    if(*(int64_t *)a < *(int64_t *)b) return 1;
    else if(*(int64_t *)a > *(int64_t *)b) return -1;
    else if ( (uint64_t)a < (uint64_t)b ) // jl777 prevent nondeterminism
        return(-1);
    else return(1);
}

static void sort64(int64_t *l, int32_t llen)
{
    qsort(l,llen,sizeof(uint64_t),cmp_llu);
}

static void revsort64(int64_t *l, int32_t llen)
{
    qsort(l,llen,sizeof(uint64_t),revcmp_llu);
}

int64_t smartusd_priceave(int64_t *buf,int64_t *correlated,int32_t cskip)
{
    int32_t i,dir=0; int64_t sum=0,nonzprice,price,halfave,thirdave,fourthave,decayprice;
    if ( PRICES_DAYWINDOW < 2 )
        return(0);
    for (i=0; i<PRICES_DAYWINDOW; i++)
    {
        if ( (nonzprice= correlated[i*cskip]) != 0 )
            break;
    }
    if ( nonzprice == 0 )
        return(-1);
    for (i=0; i<PRICES_DAYWINDOW; i++)
    {
        if ( (price= correlated[i*cskip]) != 0 )
            nonzprice = price;
        buf[PRICES_DAYWINDOW+i] = nonzprice;
        sum += nonzprice;
        if ( i == PRICES_DAYWINDOW/2 )
            halfave = (sum / (PRICES_DAYWINDOW/2));
        else if ( i == PRICES_DAYWINDOW/3 )
            thirdave = (sum / (PRICES_DAYWINDOW/3));
        else if ( i == PRICES_DAYWINDOW/4 )
            fourthave = (sum / (PRICES_DAYWINDOW/4));
    }
    memcpy(buf,&buf[PRICES_DAYWINDOW],PRICES_DAYWINDOW*sizeof(*buf));
    price = sum / PRICES_DAYWINDOW;
    return(price);
    if ( halfave == price )
        return(price);
    else if ( halfave > price ) // rising prices
        sort64(buf,PRICES_DAYWINDOW);
    else revsort64(buf,PRICES_DAYWINDOW);
    decayprice = buf[0];
    for (i=0; i<PRICES_DAYWINDOW; i++)
    {
        decayprice = ((decayprice * 97) + (buf[i] * 3)) / 100;
        //LogPrintf("%.4f ",(double)buf[i]/COIN);
    }
    LogPrintf("%ssort half %.8f %.8f %.8f %.8f %.8f %.8f -> %.8f\n",halfave<price?"rev":"",(double)price/COIN,(double)halfave/COIN,(double)thirdave/COIN,(double)fourthave/COIN,(double)decayprice/COIN,(double)buf[PRICES_DAYWINDOW-1]/COIN,(double)(price*7 + halfave*5 + thirdave*3 + fourthave*2 + decayprice + buf[PRICES_DAYWINDOW-1])/(19*COIN));
    return((price*7 + halfave*5 + thirdave*3 + fourthave*2 + decayprice + buf[PRICES_DAYWINDOW-1]) / 19);
}

int32_t smartusd_priceget(int64_t *buf64,int32_t ind,int32_t height,int32_t numblocks)
{
    FILE *fp; int32_t retval = PRICES_MAXDATAPOINTS;
    pthread_mutex_lock(&pricemutex);
    if ( ind < SMARTUSD_MAXPRICES && (fp= PRICES[ind].fp) != 0 )
    {
        fseek(fp,height * PRICES_MAXDATAPOINTS * sizeof(int64_t),SEEK_SET);
        if ( fread(buf64,sizeof(int64_t),numblocks*PRICES_MAXDATAPOINTS,fp) != numblocks*PRICES_MAXDATAPOINTS )
            retval = -1;
    }
    pthread_mutex_unlock(&pricemutex);
    return(retval);
}

// for convenience, calls eval's get transaction version if eval is set
bool myGetTransactionEval(Eval *eval, const uint256 &hash, CTransaction &txOut, uint256 &hashBlock)
{
    if (eval)
        return eval->GetTxUnconfirmed(hash, txOut, hashBlock);
    else
        return myGetTransaction(hash, txOut, hashBlock);
}

// Extra GetTransaction version that looks into current block txns or in mempool
// for use in cc validation code
bool myGetTransactionBlockTxns(const uint256 &hash, CTransaction &txOut, uint256 &hashBlock, BlockTxnsPtr blockTxns)
{
    CTransactionRef ptxOutRef;

    memset(&hashBlock,0,sizeof(hashBlock));
    // need a GetTransaction without lock so the validation code for assets can run without deadlock
    {
        if (blockTxns != nullptr)
        {
            // if a block is connecting then search in its txns instead of mempool
            // as mempool txns should not affect the txns from a connecting block
            auto foundit = blockTxns->find(hash);
            if (foundit != blockTxns->end())
            {
                txOut = foundit->second;
                return true;
            }
        }
        else
        {
            //LogPrintf("check mempool %s\n",hash.GetHex().c_str());
            if (mempool.lookup(hash, txOut))
            {
                //LogPrintf("found in mempool\n");
                return true;
            }
        }
    }
    //LogPrintf("check disk %s\n",hash.GetHex().c_str());

    if (fTxIndex) {
        CDiskTxPos postx;
        //LogPrintf("ReadTxIndex\n");
        if (pblocktree->ReadTxIndex(hash, postx)) {
            //LogPrintf("OpenBlockFile\n");
            CAutoFile file(OpenBlockFile(postx, true), SER_DISK, CLIENT_VERSION);
            if (file.IsNull())
                return error("%s: OpenBlockFile failed", __func__);
            CBlockHeader header;
            //LogPrintf("seek and read\n");
            try {
                file >> header;
                fseek(file.Get(), postx.nTxOffset, SEEK_CUR);
                // file >> txOut;

                /*
                TODO: somehow after file >> txOut (where txOut is CTransaction and not CTransactionRef), txOut.GetHash gives
                wrong result. Here it fixed by adding ptxOutRef (CTransactionRef), but better to change input params of
                myGetTransaction from CTransaction on CTransactionRef in future and modify all related code! Also, we should
                sort out that ptxOutRef->GetHash() and txOut.GetHash() mystery!
                */

                file >> ptxOutRef;
            } catch (const std::exception& e) {
                return error("%s: Deserialize or I/O error - %s", __func__, e.what());
            }
            hashBlock = header.GetHash();
            //std::cerr << __func__ << ": " << hashBlock.ToString() << " - " << ptxOutRef->GetHash().ToString() << std::endl;
            if (ptxOutRef->GetHash() != hash)
                return error("%s: txid mismatch", __func__);
            txOut = *ptxOutRef.get();
            //LogPrintf("found on disk %s\n",hash.GetHex().c_str());
            return true;
        }
    }
    //fprintf(stderr,"not found on disk %s\n",hash.GetHex().c_str());
    return false;
}

// non-blocking GetTransaction version
bool myGetTransaction(const uint256 &hash, CTransaction &txOut, uint256 &hashBlock)
{
    return myGetTransactionBlockTxns(hash, txOut, hashBlock, nullptr);
}

uint32_t ASSETCHAINS_MAGIC = 2387029918;

// get a pseudo random number that is the same for each block individually at all times and different
// from all other blocks. the sequence is extremely likely, but not guaranteed to be unique for each block chain
uint64_t smartusd_block_prg(uint32_t nHeight)
{
        int i;
        uint8_t hashSrc[8];
        uint64_t result=0, hashSrc64 = (uint64_t)ASSETCHAINS_MAGIC << 32 + nHeight;
        bits256 hashResult;

        for ( i = 0; i < sizeof(hashSrc); i++ )
        {
            hashSrc[i] = hashSrc64 & 0xff;
            hashSrc64 >>= 8;
            int8_t b = hashSrc[i];
        }

        vcalc_sha256(0, hashResult.bytes, hashSrc, sizeof(hashSrc));
        for ( i = 0; i < 8; i++ )
        {
            result = (result << 8) + hashResult.bytes[i];
        }
        return result;
}

int32_t iguana_rwnum(int32_t rwflag,uint8_t *serialized,int32_t len,void *endianedp)
{
    int32_t i; uint64_t x;
    if ( rwflag == 0 )
    {
        x = 0;
        for (i=len-1; i>=0; i--)
        {
            x <<= 8;
            x |= serialized[i];
        }
        switch ( len )
        {
            case 1: *(uint8_t *)endianedp = (uint8_t)x; break;
            case 2: *(uint16_t *)endianedp = (uint16_t)x; break;
            case 4: *(uint32_t *)endianedp = (uint32_t)x; break;
            case 8: *(uint64_t *)endianedp = (uint64_t)x; break;
        }
    }
    else
    {
        x = 0;
        switch ( len )
        {
            case 1: x = *(uint8_t *)endianedp; break;
            case 2: x = *(uint16_t *)endianedp; break;
            case 4: x = *(uint32_t *)endianedp; break;
            case 8: x = *(uint64_t *)endianedp; break;
        }
        for (i=0; i<len; i++,x >>= 8)
            serialized[i] = (uint8_t)(x & 0xff);
    }
    return(len);
}

int32_t iguana_rwbignum(int32_t rwflag,uint8_t *serialized,int32_t len,uint8_t *endianedp)
{
    int32_t i;
    if ( rwflag == 0 )
    {
        for (i=0; i<len; i++)
            endianedp[i] = serialized[i];
    }
    else
    {
        for (i=0; i<len; i++)
            serialized[i] = endianedp[i];
    }
    return(len);
}

uint256 smartusd_calcMoM(int32_t height,int32_t MoMdepth)
{
    static uint256 zero; CBlockIndex *pindex; int32_t i; std::vector<uint256> tree, leaves;
    bool fMutated;
    MoMdepth &= 0xffff;  // In case it includes the ccid
    if ( MoMdepth >= height )
        return(zero);
    for (i=0; i<MoMdepth; i++)
    {
        if ( (pindex= smartusd_chainactive(height - i)) != 0 )
            leaves.push_back(pindex->hashMerkleRoot);
        else
            return(zero);
    }
    return BuildMerkleTree(&fMutated, leaves, tree);
}

int32_t smartusd_MoM(int32_t *notarized_heightp,uint256 *MoMp,uint256 *kmdtxidp,int32_t nHeight,uint256 *MoMoMp,int32_t *MoMoMoffsetp,int32_t *MoMoMdepthp,int32_t *kmdstartip,int32_t *kmdendip)
{
    int32_t depth,notarized_ht; uint256 MoM,kmdtxid;
    depth = smartusd_MoMdata(&notarized_ht,&MoM,&kmdtxid,nHeight,MoMoMp,MoMoMoffsetp,MoMoMdepthp,kmdstartip,kmdendip);
    memset(MoMp,0,sizeof(*MoMp));
    memset(kmdtxidp,0,sizeof(*kmdtxidp));
    *notarized_heightp = 0;
    if ( depth != 0 && notarized_ht > 0 && nHeight > notarized_ht-depth && nHeight <= notarized_ht )
    {
        *MoMp = MoM;
        *notarized_heightp = notarized_ht;
        *kmdtxidp = kmdtxid;
    }
    return(depth);
}

int32_t smartusd_MoMdata(int32_t *notarized_htp,uint256 *MoMp,uint256 *kmdtxidp,int32_t height,uint256 *MoMoMp,int32_t *MoMoMoffsetp,int32_t *MoMoMdepthp,int32_t *kmdstartip,int32_t *kmdendip)
{
    struct notarized_checkpoint *np = 0;
//No notarization now
/*
    if ( (np= komodo_npptr(height)) != 0 )
    {
        *notarized_htp = np->notarized_height;
        *MoMp = np->MoM;
        *kmdtxidp = np->notarized_desttxid;
        *MoMoMp = np->MoMoM;
        *MoMoMoffsetp = np->MoMoMoffset;
        *MoMoMdepthp = np->MoMoMdepth;
        *kmdstartip = np->kmdstarti;
        *kmdendip = np->kmdendi;
        return(np->MoMdepth & 0xffff);
    }
*/
    *notarized_htp = *MoMoMoffsetp = *MoMoMdepthp = *kmdstartip = *kmdendip = 0;
    memset(MoMp,0,sizeof(*MoMp));
    memset(MoMoMp,0,sizeof(*MoMoMp));
    memset(kmdtxidp,0,sizeof(*kmdtxidp));
    return(0);
}

int32_t smartusd_notaries(uint8_t pubkeys[64][33],int32_t height,uint32_t timestamp)
{
//No notarization now
    return(0);
}

bool GetNotarisationNotaries(uint8_t notarypubkeys[64][33], int8_t &numNN, const std::vector<CTxIn> &vin, std::vector<int8_t> &NotarisationNotaries)
{
    uint8_t *script; int32_t scriptlen;
    if ( notarypubkeys[0][0] == 0 )
        return false;
    BOOST_FOREACH(const CTxIn& txin, vin)
    {
        uint256 hash; CTransactionRef tx1;
        if ( GetTransaction(txin.prevout.hash,tx1,Params().GetConsensus(),hash,false) )
        {
            for (int8_t i = 0; i < numNN; i++)
            {
                script = (uint8_t *)&tx1->vout[txin.prevout.n].scriptPubKey[0];
                scriptlen = (int32_t)tx1->vout[txin.prevout.n].scriptPubKey.size();
                if ( scriptlen == 35 && script[0] == 33 && script[34] == OP_CHECKSIG && memcmp(script+1,notarypubkeys[i],33) == 0 )
                    NotarisationNotaries.push_back(i);
            }
        } else return false;
    }
    return true;
}