Rename the remaining main.{h,cpp} to validation.{h,cpp}

1 files changed, 4190 insertions, 0 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
new file mode 100644
index 0000000000..9cfb5221a6
--- /dev/null
+++ b/src/validation.cpp
@@ -0,0 +1,4190 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2016 The Bitcoin 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 "chainparams.h"
+#include "checkpoints.h"
+#include "checkqueue.h"
+#include "consensus/consensus.h"
+#include "consensus/merkle.h"
+#include "consensus/validation.h"
+#include "hash.h"
+#include "init.h"
+#include "policy/fees.h"
+#include "policy/policy.h"
+#include "pow.h"
+#include "primitives/block.h"
+#include "primitives/transaction.h"
+#include "random.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 "versionbits.h"
+
+#include <atomic>
+#include <sstream>
+
+#include <boost/algorithm/string/replace.hpp>
+#include <boost/algorithm/string/join.hpp>
+#include <boost/filesystem.hpp>
+#include <boost/filesystem/fstream.hpp>
+#include <boost/math/distributions/poisson.hpp>
+#include <boost/thread.hpp>
+
+using namespace std;
+
+#if defined(NDEBUG)
+# error "Bitcoin cannot be compiled without assertions."
+#endif
+
+/**
+ * Global state
+ */
+
+CCriticalSection cs_main;
+
+BlockMap mapBlockIndex;
+CChain chainActive;
+CBlockIndex *pindexBestHeader = NULL;
+CWaitableCriticalSection csBestBlock;
+CConditionVariable cvBlockChange;
+int nScriptCheckThreads = 0;
+std::atomic_bool fImporting(false);
+bool fReindex = false;
+bool fTxIndex = 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;
+
+
+CFeeRate minRelayTxFee = CFeeRate(DEFAULT_MIN_RELAY_TX_FEE);
+CAmount maxTxFee = DEFAULT_TRANSACTION_MAXFEE;
+
+CTxMemPool mempool(::minRelayTxFee);
+
+static void CheckBlockIndex(const Consensus::Params& consensusParams);
+
+/** Constant stuff for coinbase transactions we create: */
+CScript COINBASE_FLAGS;
+
+const string strMessageMagic = "Bitcoin Signed Message:\n";
+
+// Internal stuff
+namespace {
+
+    struct CBlockIndexWorkComparator
+    {
+        bool operator()(CBlockIndex *pa, 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;
+        }
+    };
+
+    CBlockIndex *pindexBestInvalid;
+
+    /**
+     * 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.
+     */
+    set<CBlockIndex*, CBlockIndexWorkComparator> setBlockIndexCandidates;
+    /** 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.
+     */
+    multimap<CBlockIndex*, CBlockIndex*> 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;
+
+    /**
+     * 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;
+
+    /** Dirty block index entries. */
+    set<CBlockIndex*> setDirtyBlockIndex;
+
+    /** Dirty block file entries. */
+    set<int> setDirtyFileInfo;
+} // anon namespace
+
+CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator)
+{
+    // Find the first block the caller has in the main chain
+    BOOST_FOREACH(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();
+}
+
+CCoinsViewCache *pcoinsTip = NULL;
+CBlockTreeDB *pblocktree = NULL;
+
+enum FlushStateMode {
+    FLUSH_STATE_NONE,
+    FLUSH_STATE_IF_NEEDED,
+    FLUSH_STATE_PERIODIC,
+    FLUSH_STATE_ALWAYS
+};
+
+// See definition for documentation
+bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode);
+
+bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime)
+{
+    if (tx.nLockTime == 0)
+        return true;
+    if ((int64_t)tx.nLockTime < ((int64_t)tx.nLockTime < LOCKTIME_THRESHOLD ? (int64_t)nBlockHeight : nBlockTime))
+        return true;
+    for (const auto& txin : tx.vin) {
+        if (!(txin.nSequence == CTxIn::SEQUENCE_FINAL))
+            return false;
+    }
+    return true;
+}
+
+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 will require 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);
+}
+
+/**
+ * Calculates the block height and previous block's median time past at
+ * which the transaction will be considered final in the context of BIP 68.
+ * Also removes from the vector of input heights any entries which did not
+ * correspond to sequence locked inputs as they do not affect the calculation.
+ */
+static std::pair<int, int64_t> CalculateSequenceLocks(const CTransaction &tx, int flags, std::vector<int>* prevHeights, const CBlockIndex& block)
+{
+    assert(prevHeights->size() == tx.vin.size());
+
+    // Will be set to the equivalent height- and time-based nLockTime
+    // values that would be necessary to satisfy all relative lock-
+    // time constraints given our view of block chain history.
+    // The semantics of nLockTime are the last invalid height/time, so
+    // use -1 to have the effect of any height or time being valid.
+    int nMinHeight = -1;
+    int64_t nMinTime = -1;
+
+    // tx.nVersion is signed integer so requires cast to unsigned otherwise
+    // we would be doing a signed comparison and half the range of nVersion
+    // wouldn't support BIP 68.
+    bool fEnforceBIP68 = static_cast<uint32_t>(tx.nVersion) >= 2
+                      && flags & LOCKTIME_VERIFY_SEQUENCE;
+
+    // Do not enforce sequence numbers as a relative lock time
+    // unless we have been instructed to
+    if (!fEnforceBIP68) {
+        return std::make_pair(nMinHeight, nMinTime);
+    }
+
+    for (size_t txinIndex = 0; txinIndex < tx.vin.size(); txinIndex++) {
+        const CTxIn& txin = tx.vin[txinIndex];
+
+        // Sequence numbers with the most significant bit set are not
+        // treated as relative lock-times, nor are they given any
+        // consensus-enforced meaning at this point.
+        if (txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_DISABLE_FLAG) {
+            // The height of this input is not relevant for sequence locks
+            (*prevHeights)[txinIndex] = 0;
+            continue;
+        }
+
+        int nCoinHeight = (*prevHeights)[txinIndex];
+
+        if (txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_TYPE_FLAG) {
+            int64_t nCoinTime = block.GetAncestor(std::max(nCoinHeight-1, 0))->GetMedianTimePast();
+            // NOTE: Subtract 1 to maintain nLockTime semantics
+            // BIP 68 relative lock times have the semantics of calculating
+            // the first block or time at which the transaction would be
+            // valid. When calculating the effective block time or height
+            // for the entire transaction, we switch to using the
+            // semantics of nLockTime which is the last invalid block
+            // time or height.  Thus we subtract 1 from the calculated
+            // time or height.
+
+            // Time-based relative lock-times are measured from the
+            // smallest allowed timestamp of the block containing the
+            // txout being spent, which is the median time past of the
+            // block prior.
+            nMinTime = std::max(nMinTime, nCoinTime + (int64_t)((txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_MASK) << CTxIn::SEQUENCE_LOCKTIME_GRANULARITY) - 1);
+        } else {
+            nMinHeight = std::max(nMinHeight, nCoinHeight + (int)(txin.nSequence & CTxIn::SEQUENCE_LOCKTIME_MASK) - 1);
+        }
+    }
+
+    return std::make_pair(nMinHeight, nMinTime);
+}
+
+static bool EvaluateSequenceLocks(const CBlockIndex& block, std::pair<int, int64_t> lockPair)
+{
+    assert(block.pprev);
+    int64_t nBlockTime = block.pprev->GetMedianTimePast();
+    if (lockPair.first >= block.nHeight || lockPair.second >= nBlockTime)
+        return false;
+
+    return true;
+}
+
+bool SequenceLocks(const CTransaction &tx, int flags, std::vector<int>* prevHeights, const CBlockIndex& block)
+{
+    return EvaluateSequenceLocks(block, CalculateSequenceLocks(tx, flags, prevHeights, block));
+}
+
+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();
+    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, 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];
+            CCoins coins;
+            if (!viewMemPool.GetCoins(txin.prevout.hash, coins)) {
+                return error("%s: Missing input", __func__);
+            }
+            if (coins.nHeight == MEMPOOL_HEIGHT) {
+                // Assume all mempool transaction confirm in the next block
+                prevheights[txinIndex] = tip->nHeight + 1;
+            } else {
+                prevheights[txinIndex] = coins.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;
+            BOOST_FOREACH(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);
+}
+
+
+unsigned int GetLegacySigOpCount(const CTransaction& tx)
+{
+    unsigned int nSigOps = 0;
+    for (const auto& txin : tx.vin)
+    {
+        nSigOps += txin.scriptSig.GetSigOpCount(false);
+    }
+    for (const auto& txout : tx.vout)
+    {
+        nSigOps += txout.scriptPubKey.GetSigOpCount(false);
+    }
+    return nSigOps;
+}
+
+unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& inputs)
+{
+    if (tx.IsCoinBase())
+        return 0;
+
+    unsigned int nSigOps = 0;
+    for (unsigned int i = 0; i < tx.vin.size(); i++)
+    {
+        const CTxOut &prevout = inputs.GetOutputFor(tx.vin[i]);
+        if (prevout.scriptPubKey.IsPayToScriptHash())
+            nSigOps += prevout.scriptPubKey.GetSigOpCount(tx.vin[i].scriptSig);
+    }
+    return nSigOps;
+}
+
+int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, int flags)
+{
+    int64_t nSigOps = GetLegacySigOpCount(tx) * WITNESS_SCALE_FACTOR;
+
+    if (tx.IsCoinBase())
+        return nSigOps;
+
+    if (flags & SCRIPT_VERIFY_P2SH) {
+        nSigOps += GetP2SHSigOpCount(tx, inputs) * WITNESS_SCALE_FACTOR;
+    }
+
+    for (unsigned int i = 0; i < tx.vin.size(); i++)
+    {
+        const CTxOut &prevout = inputs.GetOutputFor(tx.vin[i]);
+        nSigOps += CountWitnessSigOps(tx.vin[i].scriptSig, prevout.scriptPubKey, i < tx.wit.vtxinwit.size() ? &tx.wit.vtxinwit[i].scriptWitness : NULL, flags);
+    }
+    return nSigOps;
+}
+
+
+
+
+
+bool CheckTransaction(const CTransaction& tx, CValidationState &state, bool fCheckDuplicateInputs)
+{
+    // Basic checks that don't depend on any context
+    if (tx.vin.empty())
+        return state.DoS(10, false, REJECT_INVALID, "bad-txns-vin-empty");
+    if (tx.vout.empty())
+        return state.DoS(10, false, REJECT_INVALID, "bad-txns-vout-empty");
+    // Size limits (this doesn't take the witness into account, as that hasn't been checked for malleability)
+    if (::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) > MAX_BLOCK_BASE_SIZE)
+        return state.DoS(100, false, REJECT_INVALID, "bad-txns-oversize");
+
+    // Check for negative or overflow output values
+    CAmount nValueOut = 0;
+    for (const auto& txout : tx.vout)
+    {
+        if (txout.nValue < 0)
+            return state.DoS(100, false, REJECT_INVALID, "bad-txns-vout-negative");
+        if (txout.nValue > MAX_MONEY)
+            return state.DoS(100, false, REJECT_INVALID, "bad-txns-vout-toolarge");
+        nValueOut += txout.nValue;
+        if (!MoneyRange(nValueOut))
+            return state.DoS(100, false, REJECT_INVALID, "bad-txns-txouttotal-toolarge");
+    }
+
+    // Check for duplicate inputs - note that this check is slow so we skip it in CheckBlock
+    if (fCheckDuplicateInputs) {
+        set<COutPoint> vInOutPoints;
+        for (const auto& txin : tx.vin)
+        {
+            if (!vInOutPoints.insert(txin.prevout).second)
+                return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputs-duplicate");
+        }
+    }
+
+    if (tx.IsCoinBase())
+    {
+        if (tx.vin[0].scriptSig.size() < 2 || tx.vin[0].scriptSig.size() > 100)
+            return state.DoS(100, false, REJECT_INVALID, "bad-cb-length");
+    }
+    else
+    {
+        for (const auto& txin : tx.vin)
+            if (txin.prevout.IsNull())
+                return state.DoS(10, false, REJECT_INVALID, "bad-txns-prevout-null");
+    }
+
+    return true;
+}
+
+void LimitMempoolSize(CTxMemPool& pool, size_t limit, unsigned long age) {
+    int expired = pool.Expire(GetTime() - age);
+    if (expired != 0)
+        LogPrint("mempool", "Expired %i transactions from the memory pool\n", expired);
+
+    std::vector<uint256> vNoSpendsRemaining;
+    pool.TrimToSize(limit, &vNoSpendsRemaining);
+    BOOST_FOREACH(const uint256& 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());
+}
+
+bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const CTransaction& tx, bool fLimitFree,
+                              bool* pfMissingInputs, int64_t nAcceptTime, bool fOverrideMempoolLimit, const CAmount& nAbsurdFee,
+                              std::vector<uint256>& vHashTxnToUncache)
+{
+    const uint256 hash = tx.GetHash();
+    AssertLockHeld(cs_main);
+    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");
+
+    // Don't relay version 2 transactions until CSV is active, and we can be
+    // sure that such transactions will be mined (unless we're on
+    // -testnet/-regtest).
+    const CChainParams& chainparams = Params();
+    if (fRequireStandard && tx.nVersion >= 2 && VersionBitsTipState(chainparams.GetConsensus(), Consensus::DEPLOYMENT_CSV) != THRESHOLD_ACTIVE) {
+        return state.DoS(0, false, REJECT_NONSTANDARD, "premature-version2-tx");
+    }
+
+    // Reject transactions with witness before segregated witness activates (override with -prematurewitness)
+    bool witnessEnabled = IsWitnessEnabled(chainActive.Tip(), Params().GetConsensus());
+    if (!GetBoolArg("-prematurewitness",false) && !tx.wit.IsNull() && !witnessEnabled) {
+        return state.DoS(0, false, REJECT_NONSTANDARD, "no-witness-yet", true);
+    }
+
+    // Rather not work on nonstandard transactions (unless -testnet/-regtest)
+    string reason;
+    if (fRequireStandard && !IsStandardTx(tx, reason, witnessEnabled))
+        return state.DoS(0, false, REJECT_NONSTANDARD, reason);
+
+    // 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_ALREADY_KNOWN, "txn-already-in-mempool");
+
+    // Check for conflicts with in-memory transactions
+    set<uint256> setConflicts;
+    {
+    LOCK(pool.cs); // protect pool.mapNextTx
+    BOOST_FOREACH(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 >= maxint-1 on all inputs.
+                //
+                // maxint-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)
+                {
+                    BOOST_FOREACH(const CTxIn &_txin, ptxConflicting->vin)
+                    {
+                        if (_txin.nSequence < std::numeric_limits<unsigned int>::max()-1)
+                        {
+                            fReplacementOptOut = false;
+                            break;
+                        }
+                    }
+                }
+                if (fReplacementOptOut)
+                    return state.Invalid(false, REJECT_CONFLICT, "txn-mempool-conflict");
+
+                setConflicts.insert(ptxConflicting->GetHash());
+            }
+        }
+    }
+    }
+
+    {
+        CCoinsView dummy;
+        CCoinsViewCache view(&dummy);
+
+        CAmount nValueIn = 0;
+        LockPoints lp;
+        {
+        LOCK(pool.cs);
+        CCoinsViewMemPool viewMemPool(pcoinsTip, pool);
+        view.SetBackend(viewMemPool);
+
+        // do we already have it?
+        bool fHadTxInCache = pcoinsTip->HaveCoinsInCache(hash);
+        if (view.HaveCoins(hash)) {
+            if (!fHadTxInCache)
+                vHashTxnToUncache.push_back(hash);
+            return state.Invalid(false, REJECT_ALREADY_KNOWN, "txn-already-known");
+        }
+
+        // do all inputs exist?
+        // Note that this does not check for the presence of actual outputs (see the next check for that),
+        // and only helps with filling in pfMissingInputs (to determine missing vs spent).
+        BOOST_FOREACH(const CTxIn txin, tx.vin) {
+            if (!pcoinsTip->HaveCoinsInCache(txin.prevout.hash))
+                vHashTxnToUncache.push_back(txin.prevout.hash);
+            if (!view.HaveCoins(txin.prevout.hash)) {
+                if (pfMissingInputs)
+                    *pfMissingInputs = true;
+                return false; // fMissingInputs and !state.IsInvalid() is used to detect this condition, don't set state.Invalid()
+            }
+        }
+
+        // are the actual inputs available?
+        if (!view.HaveInputs(tx))
+            return state.Invalid(false, REJECT_DUPLICATE, "bad-txns-inputs-spent");
+
+        // Bring the best block into scope
+        view.GetBestBlock();
+
+        nValueIn = view.GetValueIn(tx);
+
+        // 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");
+        }
+
+        // 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.wit.IsNull() && 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);
+
+        CAmount nValueOut = tx.GetValueOut();
+        CAmount nFees = nValueIn-nValueOut;
+        // nModifiedFees includes any fee deltas from PrioritiseTransaction
+        CAmount nModifiedFees = nFees;
+        double nPriorityDummy = 0;
+        pool.ApplyDeltas(hash, nPriorityDummy, nModifiedFees);
+
+        CAmount inChainInputValue;
+        double dPriority = view.GetPriority(tx, chainActive.Height(), inChainInputValue);
+
+        // Keep track of transactions that spend a coinbase, which we re-scan
+        // during reorgs to ensure COINBASE_MATURITY is still met.
+        bool fSpendsCoinbase = false;
+        BOOST_FOREACH(const CTxIn &txin, tx.vin) {
+            const CCoins *coins = view.AccessCoins(txin.prevout.hash);
+            if (coins->IsCoinBase()) {
+                fSpendsCoinbase = true;
+                break;
+            }
+        }
+
+        CTxMemPoolEntry entry(tx, nFees, nAcceptTime, dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, 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(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFee(nSize);
+        if (mempoolRejectFee > 0 && nModifiedFees < mempoolRejectFee) {
+            return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool min fee not met", false, strprintf("%d < %d", nFees, mempoolRejectFee));
+        } else if (GetBoolArg("-relaypriority", DEFAULT_RELAYPRIORITY) && nModifiedFees < ::minRelayTxFee.GetFee(nSize) && !AllowFree(entry.GetPriority(chainActive.Height() + 1))) {
+            // Require that free transactions have sufficient priority to be mined in the next block.
+            return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "insufficient priority");
+        }
+
+        // Continuously rate-limit free (really, very-low-fee) transactions
+        // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
+        // be annoying or make others' transactions take longer to confirm.
+        if (fLimitFree && nModifiedFees < ::minRelayTxFee.GetFee(nSize))
+        {
+            static CCriticalSection csFreeLimiter;
+            static double dFreeCount;
+            static int64_t nLastTime;
+            int64_t nNow = GetTime();
+
+            LOCK(csFreeLimiter);
+
+            // Use an exponentially decaying ~10-minute window:
+            dFreeCount *= pow(1.0 - 1.0/600.0, (double)(nNow - nLastTime));
+            nLastTime = nNow;
+            // -limitfreerelay unit is thousand-bytes-per-minute
+            // At default rate it would take over a month to fill 1GB
+            if (dFreeCount + nSize >= GetArg("-limitfreerelay", DEFAULT_LIMITFREERELAY) * 10 * 1000)
+                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "rate limited free transaction");
+            LogPrint("mempool", "Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize);
+            dFreeCount += nSize;
+        }
+
+        if (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 = GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
+        size_t nLimitAncestorSize = GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT)*1000;
+        size_t nLimitDescendants = GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT);
+        size_t nLimitDescendantSize = 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.
+        BOOST_FOREACH(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.
+        LOCK(pool.cs);
+        if (setConflicts.size())
+        {
+            CFeeRate newFeeRate(nModifiedFees, nSize);
+            set<uint256> setConflictsParents;
+            const int maxDescendantsToVisit = 100;
+            CTxMemPool::setEntries setIterConflicting;
+            BOOST_FOREACH(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()));
+                }
+
+                BOOST_FOREACH(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
+                BOOST_FOREACH(CTxMemPool::txiter it, setIterConflicting) {
+                    pool.CalculateDescendants(it, allConflicting);
+                }
+                BOOST_FOREACH(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 < ::minRelayTxFee.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(::minRelayTxFee.GetFee(nSize))));
+            }
+        }
+
+        unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS;
+        if (!Params().RequireStandard()) {
+            scriptVerifyFlags = 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, txdata)) {
+            // 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.
+            if (tx.wit.IsNull() && CheckInputs(tx, state, view, true, scriptVerifyFlags & ~(SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_CLEANSTACK), true, txdata) &&
+                !CheckInputs(tx, state, view, true, scriptVerifyFlags & ~SCRIPT_VERIFY_CLEANSTACK, true, txdata)) {
+                // Only the witness is missing, so the transaction itself may be fine.
+                state.SetCorruptionPossible();
+            }
+            return false;
+        }
+
+        // Check again against just the consensus-critical mandatory script
+        // verification flags, 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, however allowing such transactions into the mempool
+        // can be exploited as a DoS attack.
+        if (!CheckInputs(tx, state, view, true, MANDATORY_SCRIPT_VERIFY_FLAGS, true, txdata))
+        {
+            return error("%s: BUG! PLEASE REPORT THIS! ConnectInputs failed against MANDATORY but not STANDARD flags %s, %s",
+                __func__, hash.ToString(), FormatStateMessage(state));
+        }
+
+        // Remove conflicting transactions from the mempool
+        BOOST_FOREACH(const CTxMemPool::txiter it, allConflicting)
+        {
+            LogPrint("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);
+        }
+        pool.RemoveStaged(allConflicting, false);
+
+        // Store transaction in memory
+        pool.addUnchecked(hash, entry, setAncestors, !IsInitialBlockDownload());
+
+        // trim mempool and check if tx was trimmed
+        if (!fOverrideMempoolLimit) {
+            LimitMempoolSize(pool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
+            if (!pool.exists(hash))
+                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool full");
+        }
+    }
+
+    GetMainSignals().SyncTransaction(tx, NULL, CMainSignals::SYNC_TRANSACTION_NOT_IN_BLOCK);
+
+    return true;
+}
+
+bool AcceptToMemoryPoolWithTime(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
+                        bool* pfMissingInputs, int64_t nAcceptTime, bool fOverrideMempoolLimit, const CAmount nAbsurdFee)
+{
+    std::vector<uint256> vHashTxToUncache;
+    bool res = AcceptToMemoryPoolWorker(pool, state, tx, fLimitFree, pfMissingInputs, nAcceptTime, fOverrideMempoolLimit, nAbsurdFee, vHashTxToUncache);
+    if (!res) {
+        BOOST_FOREACH(const uint256& hashTx, vHashTxToUncache)
+            pcoinsTip->Uncache(hashTx);
+    }
+    // After we've (potentially) uncached entries, ensure our coins cache is still within its size limits
+    CValidationState stateDummy;
+    FlushStateToDisk(stateDummy, FLUSH_STATE_PERIODIC);
+    return res;
+}
+
+bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
+                        bool* pfMissingInputs, bool fOverrideMempoolLimit, const CAmount nAbsurdFee)
+{
+    return AcceptToMemoryPoolWithTime(pool, state, tx, fLimitFree, pfMissingInputs, GetTime(), fOverrideMempoolLimit, nAbsurdFee);
+}
+
+/** Return transaction in txOut, and if it was found inside a block, its hash is placed in hashBlock */
+bool GetTransaction(const uint256 &hash, CTransaction &txOut, const Consensus::Params& consensusParams, uint256 &hashBlock, bool fAllowSlow)
+{
+    CBlockIndex *pindexSlow = NULL;
+
+    LOCK(cs_main);
+
+    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;
+        }
+    }
+
+    if (fAllowSlow) { // use coin database to locate block that contains transaction, and scan it
+        int nHeight = -1;
+        {
+            const CCoinsViewCache& view = *pcoinsTip;
+            const CCoins* coins = view.AccessCoins(hash);
+            if (coins)
+                nHeight = coins->nHeight;
+        }
+        if (nHeight > 0)
+            pindexSlow = chainActive[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 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;
+}
+
+bool ReadBlockFromDisk(CBlock& 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.GetHash(), block.nBits, consensusParams))
+        return error("ReadBlockFromDisk: Errors in block header at %s", pos.ToString());
+
+    return true;
+}
+
+bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
+{
+    if (!ReadBlockFromDisk(block, pindex->GetBlockPos(), 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;
+}
+
+CAmount GetBlockSubsidy(int nHeight, const Consensus::Params& consensusParams)
+{
+    int halvings = nHeight / consensusParams.nSubsidyHalvingInterval;
+    // Force block reward to zero when right shift is undefined.
+    if (halvings >= 64)
+        return 0;
+
+    CAmount nSubsidy = 50 * COIN;
+    // Subsidy is cut in half every 210,000 blocks which will occur approximately every 4 years.
+    nSubsidy >>= halvings;
+    return nSubsidy;
+}
+
+bool IsInitialBlockDownload()
+{
+    const CChainParams& chainParams = Params();
+
+    // 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() == NULL)
+        return true;
+    if (chainActive.Tip()->nChainWork < UintToArith256(chainParams.GetConsensus().nMinimumChainWork))
+        return true;
+    if (chainActive.Tip()->GetBlockTime() < (GetTime() - nMaxTipAge))
+        return true;
+    latchToFalse.store(true, std::memory_order_relaxed);
+    return false;
+}
+
+bool fLargeWorkForkFound = false;
+bool fLargeWorkInvalidChainFound = false;
+CBlockIndex *pindexBestForkTip = NULL, *pindexBestForkBase = NULL;
+
+static void AlertNotify(const std::string& strMessage)
+{
+    uiInterface.NotifyAlertChanged();
+    std::string strCmd = 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
+}
+
+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 = NULL;
+
+    if (pindexBestForkTip || (pindexBestInvalid && pindexBestInvalid->nChainWork > chainActive.Tip()->nChainWork + (GetBlockProof(*chainActive.Tip()) * 6)))
+    {
+        if (!fLargeWorkForkFound && 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());
+            fLargeWorkForkFound = true;
+        }
+        else
+        {
+            LogPrintf("%s: Warning: Found invalid chain at least ~6 blocks longer than our best chain.\nChain state database corruption likely.\n", __func__);
+            fLargeWorkInvalidChainFound = true;
+        }
+    }
+    else
+    {
+        fLargeWorkForkFound = false;
+        fLargeWorkInvalidChainFound = false;
+    }
+}
+
+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 || (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 static InvalidBlockFound(CBlockIndex *pindex, const CValidationState &state) {
+    if (!state.CorruptionPossible()) {
+        pindex->nStatus |= BLOCK_FAILED_VALID;
+        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());
+        BOOST_FOREACH(const CTxIn &txin, tx.vin) {
+            CCoinsModifier coins = inputs.ModifyCoins(txin.prevout.hash);
+            unsigned nPos = txin.prevout.n;
+
+            if (nPos >= coins->vout.size() || coins->vout[nPos].IsNull())
+                assert(false);
+            // mark an outpoint spent, and construct undo information
+            txundo.vprevout.push_back(CTxInUndo(coins->vout[nPos]));
+            coins->Spend(nPos);
+            if (coins->vout.size() == 0) {
+                CTxInUndo& undo = txundo.vprevout.back();
+                undo.nHeight = coins->nHeight;
+                undo.fCoinBase = coins->fCoinBase;
+                undo.nVersion = coins->nVersion;
+            }
+        }
+    }
+    // add outputs
+    inputs.ModifyNewCoins(tx.GetHash(), tx.IsCoinBase())->FromTx(tx, 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 = (nIn < ptxTo->wit.vtxinwit.size()) ? &ptxTo->wit.vtxinwit[nIn].scriptWitness : NULL;
+    if (!VerifyScript(scriptSig, scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, amount, cacheStore, *txdata), &error)) {
+        return false;
+    }
+    return true;
+}
+
+int GetSpendHeight(const CCoinsViewCache& inputs)
+{
+    LOCK(cs_main);
+    CBlockIndex* pindexPrev = mapBlockIndex.find(inputs.GetBestBlock())->second;
+    return pindexPrev->nHeight + 1;
+}
+
+namespace Consensus {
+bool CheckTxInputs(const CTransaction& tx, CValidationState& state, const CCoinsViewCache& inputs, int nSpendHeight)
+{
+        // This doesn't trigger the DoS code on purpose; if it did, it would make it easier
+        // for an attacker to attempt to split the network.
+        if (!inputs.HaveInputs(tx))
+            return state.Invalid(false, 0, "", "Inputs unavailable");
+
+        CAmount nValueIn = 0;
+        CAmount nFees = 0;
+        for (unsigned int i = 0; i < tx.vin.size(); i++)
+        {
+            const COutPoint &prevout = tx.vin[i].prevout;
+            const CCoins *coins = inputs.AccessCoins(prevout.hash);
+            assert(coins);
+
+            // If prev is coinbase, check that it's matured
+            if (coins->IsCoinBase()) {
+                if (nSpendHeight - coins->nHeight < COINBASE_MATURITY)
+                    return state.Invalid(false,
+                        REJECT_INVALID, "bad-txns-premature-spend-of-coinbase",
+                        strprintf("tried to spend coinbase at depth %d", nSpendHeight - coins->nHeight));
+            }
+
+            // Check for negative or overflow input values
+            nValueIn += coins->vout[prevout.n].nValue;
+            if (!MoneyRange(coins->vout[prevout.n].nValue) || !MoneyRange(nValueIn))
+                return state.DoS(100, false, REJECT_INVALID, "bad-txns-inputvalues-outofrange");
+
+        }
+
+        if (nValueIn < tx.GetValueOut())
+            return state.DoS(100, false, REJECT_INVALID, "bad-txns-in-belowout", false,
+                strprintf("value in (%s) < value out (%s)", FormatMoney(nValueIn), FormatMoney(tx.GetValueOut())));
+
+        // Tally transaction fees
+        CAmount nTxFee = nValueIn - tx.GetValueOut();
+        if (nTxFee < 0)
+            return state.DoS(100, false, REJECT_INVALID, "bad-txns-fee-negative");
+        nFees += nTxFee;
+        if (!MoneyRange(nFees))
+            return state.DoS(100, false, REJECT_INVALID, "bad-txns-fee-outofrange");
+    return true;
+}
+}// namespace Consensus
+
+bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, PrecomputedTransactionData& txdata, std::vector<CScriptCheck> *pvChecks)
+{
+    if (!tx.IsCoinBase())
+    {
+        if (!Consensus::CheckTxInputs(tx, state, inputs, GetSpendHeight(inputs)))
+            return false;
+
+        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 ECDSA signature verification when connecting blocks before the
+        // last block chain checkpoint. Assuming the checkpoints are valid this
+        // is safe because block merkle hashes are still computed and checked,
+        // and any change will be caught at the next checkpoint. Of course, if
+        // the checkpoint is for a chain that's invalid due to false scriptSigs
+        // this optimization would allow an invalid chain to be accepted.
+        if (fScriptChecks) {
+            for (unsigned int i = 0; i < tx.vin.size(); i++) {
+                const COutPoint &prevout = tx.vin[i].prevout;
+                const CCoins* coins = inputs.AccessCoins(prevout.hash);
+                assert(coins);
+
+                // Verify signature
+                CScriptCheck check(*coins, tx, i, flags, cacheStore, &txdata);
+                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(*coins, tx, i,
+                                flags & ~STANDARD_NOT_MANDATORY_VERIFY_FLAGS, cacheStore, &txdata);
+                        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. a 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())));
+                }
+            }
+        }
+    }
+
+    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;
+}
+
+bool UndoReadFromDisk(CBlockUndo& blockundo, const CDiskBlockPos& pos, const uint256& hashBlock)
+{
+    // 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;
+    try {
+        filein >> blockundo;
+        filein >> hashChecksum;
+    }
+    catch (const std::exception& e) {
+        return error("%s: Deserialize or I/O error - %s", __func__, e.what());
+    }
+
+    // Verify checksum
+    CHashWriter hasher(SER_GETHASH, PROTOCOL_VERSION);
+    hasher << hashBlock;
+    hasher << blockundo;
+    if (hashChecksum != hasher.GetHash())
+        return error("%s: Checksum mismatch", __func__);
+
+    return true;
+}
+
+/** Abort with a message */
+bool AbortNode(const std::string& strMessage, const std::string& userMessage="")
+{
+    strMiscWarning = 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);
+}
+
+} // anon namespace
+
+/**
+ * Apply the undo operation of a CTxInUndo to the given chain state.
+ * @param undo The undo object.
+ * @param view The coins view to which to apply the changes.
+ * @param out The out point that corresponds to the tx input.
+ * @return True on success.
+ */
+static bool ApplyTxInUndo(const CTxInUndo& undo, CCoinsViewCache& view, const COutPoint& out)
+{
+    bool fClean = true;
+
+    CCoinsModifier coins = view.ModifyCoins(out.hash);
+    if (undo.nHeight != 0) {
+        // undo data contains height: this is the last output of the prevout tx being spent
+        if (!coins->IsPruned())
+            fClean = fClean && error("%s: undo data overwriting existing transaction", __func__);
+        coins->Clear();
+        coins->fCoinBase = undo.fCoinBase;
+        coins->nHeight = undo.nHeight;
+        coins->nVersion = undo.nVersion;
+    } else {
+        if (coins->IsPruned())
+            fClean = fClean && error("%s: undo data adding output to missing transaction", __func__);
+    }
+    if (coins->IsAvailable(out.n))
+        fClean = fClean && error("%s: undo data overwriting existing output", __func__);
+    if (coins->vout.size() < out.n+1)
+        coins->vout.resize(out.n+1);
+    coins->vout[out.n] = undo.txout;
+
+    return fClean;
+}
+
+bool DisconnectBlock(const CBlock& block, CValidationState& state, const CBlockIndex* pindex, CCoinsViewCache& view, bool* pfClean)
+{
+    assert(pindex->GetBlockHash() == view.GetBestBlock());
+
+    if (pfClean)
+        *pfClean = false;
+
+    bool fClean = true;
+
+    CBlockUndo blockUndo;
+    CDiskBlockPos pos = pindex->GetUndoPos();
+    if (pos.IsNull())
+        return error("DisconnectBlock(): no undo data available");
+    if (!UndoReadFromDisk(blockUndo, pos, pindex->pprev->GetBlockHash()))
+        return error("DisconnectBlock(): failure reading undo data");
+
+    if (blockUndo.vtxundo.size() + 1 != block.vtx.size())
+        return error("DisconnectBlock(): block and undo data inconsistent");
+
+    // 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();
+
+        // Check that all outputs are available and match the outputs in the block itself
+        // exactly.
+        {
+        CCoinsModifier outs = view.ModifyCoins(hash);
+        outs->ClearUnspendable();
+
+        CCoins outsBlock(tx, pindex->nHeight);
+        // The CCoins serialization does not serialize negative numbers.
+        // No network rules currently depend on the version here, so an inconsistency is harmless
+        // but it must be corrected before txout nversion ever influences a network rule.
+        if (outsBlock.nVersion < 0)
+            outs->nVersion = outsBlock.nVersion;
+        if (*outs != outsBlock)
+            fClean = fClean && error("DisconnectBlock(): added transaction mismatch? database corrupted");
+
+        // remove outputs
+        outs->Clear();
+        }
+
+        // restore inputs
+        if (i > 0) { // not coinbases
+            const CTxUndo &txundo = blockUndo.vtxundo[i-1];
+            if (txundo.vprevout.size() != tx.vin.size())
+                return error("DisconnectBlock(): transaction and undo data inconsistent");
+            for (unsigned int j = tx.vin.size(); j-- > 0;) {
+                const COutPoint &out = tx.vin[j].prevout;
+                const CTxInUndo &undo = txundo.vprevout[j];
+                if (!ApplyTxInUndo(undo, view, out))
+                    fClean = false;
+            }
+        }
+    }
+
+    // move best block pointer to prevout block
+    view.SetBestBlock(pindex->pprev->GetBlockHash());
+
+    if (pfClean) {
+        *pfClean = fClean;
+        return true;
+    }
+
+    return fClean;
+}
+
+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);
+    }
+}
+
+bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos, unsigned int nAddSize);
+
+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, (Consensus::DeploymentPos)i, versionbitscache);
+        if (state == THRESHOLD_LOCKED_IN || state == THRESHOLD_STARTED) {
+            nVersion |= VersionBitsMask(params, (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:
+    WarningBitsConditionChecker(int bitIn) : bit(bitIn) {}
+
+    int64_t BeginTime(const Consensus::Params& params) const { return 0; }
+    int64_t EndTime(const Consensus::Params& params) const { return std::numeric_limits<int64_t>::max(); }
+    int Period(const Consensus::Params& params) const { return params.nMinerConfirmationWindow; }
+    int Threshold(const Consensus::Params& params) const { return params.nRuleChangeActivationThreshold; }
+
+    bool Condition(const CBlockIndex* pindex, const Consensus::Params& params) const
+    {
+        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 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;
+
+bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex,
+                  CCoinsViewCache& view, const CChainParams& chainparams, bool fJustCheck)
+{
+    AssertLockHeld(cs_main);
+
+    int64_t nTimeStart = GetTimeMicros();
+
+    // Check it again in case a previous version let a bad block in
+    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 == NULL ? 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;
+    }
+
+    bool fScriptChecks = true;
+    if (fCheckpointsEnabled) {
+        CBlockIndex *pindexLastCheckpoint = Checkpoints::GetLastCheckpoint(chainparams.Checkpoints());
+        if (pindexLastCheckpoint && pindexLastCheckpoint->GetAncestor(pindex->nHeight) == pindex) {
+            // This block is an ancestor of a checkpoint: disable script checks
+            fScriptChecks = false;
+        }
+    }
+
+    int64_t nTime1 = GetTimeMicros(); nTimeCheck += nTime1 - nTimeStart;
+    LogPrint("bench", "    - Sanity checks: %.2fms [%.2fs]\n", 0.001 * (nTime1 - nTimeStart), nTimeCheck * 0.000001);
+
+    // 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.
+    // This rule was originally applied to all blocks with a timestamp after March 15, 2012, 0:00 UTC.
+    // Now that the whole chain is irreversibly beyond that time it is applied to all blocks except the
+    // two in the chain that violate it. This prevents exploiting the issue against nodes during their
+    // initial block download.
+    bool fEnforceBIP30 = (!pindex->phashBlock) || // Enforce on CreateNewBlock invocations which don't have a hash.
+                          !((pindex->nHeight==91842 && pindex->GetBlockHash() == uint256S("0x00000000000a4d0a398161ffc163c503763b1f4360639393e0e4c8e300e0caec")) ||
+                           (pindex->nHeight==91880 && pindex->GetBlockHash() == uint256S("0x00000000000743f190a18c5577a3c2d2a1f610ae9601ac046a38084ccb7cd721")));
+
+    // 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.
+    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) {
+            const CCoins* coins = view.AccessCoins(tx->GetHash());
+            if (coins && !coins->IsPruned())
+                return state.DoS(100, error("ConnectBlock(): tried to overwrite transaction"),
+                                 REJECT_INVALID, "bad-txns-BIP30");
+        }
+    }
+
+    // BIP16 didn't become active until Apr 1 2012
+    int64_t nBIP16SwitchTime = 1333238400;
+    bool fStrictPayToScriptHash = (pindex->GetBlockTime() >= nBIP16SwitchTime);
+
+    unsigned int flags = fStrictPayToScriptHash ? SCRIPT_VERIFY_P2SH : SCRIPT_VERIFY_NONE;
+
+    // Start enforcing the DERSIG (BIP66) rule
+    if (pindex->nHeight >= chainparams.GetConsensus().BIP66Height) {
+        flags |= SCRIPT_VERIFY_DERSIG;
+    }
+
+    // Start enforcing CHECKLOCKTIMEVERIFY (BIP65) rule
+    if (pindex->nHeight >= chainparams.GetConsensus().BIP65Height) {
+        flags |= SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY;
+    }
+
+    // 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) {
+        flags |= SCRIPT_VERIFY_CHECKSEQUENCEVERIFY;
+        nLockTimeFlags |= LOCKTIME_VERIFY_SEQUENCE;
+    }
+
+    // Start enforcing WITNESS rules using versionbits logic.
+    if (IsWitnessEnabled(pindex->pprev, chainparams.GetConsensus())) {
+        flags |= SCRIPT_VERIFY_WITNESS;
+        flags |= SCRIPT_VERIFY_NULLDUMMY;
+    }
+
+    int64_t nTime2 = GetTimeMicros(); nTimeForks += nTime2 - nTime1;
+    LogPrint("bench", "    - Fork checks: %.2fms [%.2fs]\n", 0.001 * (nTime2 - nTime1), nTimeForks * 0.000001);
+
+    CBlockUndo blockundo;
+
+    CCheckQueueControl<CScriptCheck> control(fScriptChecks && nScriptCheckThreads ? &scriptcheckqueue : NULL);
+
+    std::vector<int> prevheights;
+    CAmount nFees = 0;
+    int nInputs = 0;
+    int64_t nSigOpsCost = 0;
+    CDiskTxPos pos(pindex->GetBlockPos(), GetSizeOfCompactSize(block.vtx.size()));
+    std::vector<std::pair<uint256, CDiskTxPos> > vPos;
+    vPos.reserve(block.vtx.size());
+    blockundo.vtxundo.reserve(block.vtx.size() - 1);
+    std::vector<PrecomputedTransactionData> txdata;
+    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]);
+
+        nInputs += tx.vin.size();
+
+        if (!tx.IsCoinBase())
+        {
+            if (!view.HaveInputs(tx))
+                return state.DoS(100, error("ConnectBlock(): inputs missing/spent"),
+                                 REJECT_INVALID, "bad-txns-inputs-missingorspent");
+
+            // 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.AccessCoins(tx.vin[j].prevout.hash)->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");
+            }
+        }
+
+        // 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())
+        {
+            nFees += view.GetValueIn(tx)-tx.GetValueOut();
+
+            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, txdata[i], nScriptCheckThreads ? &vChecks : NULL))
+                return error("ConnectBlock(): CheckInputs on %s failed with %s",
+                    tx.GetHash().ToString(), FormatStateMessage(state));
+            control.Add(vChecks);
+        }
+
+        CTxUndo undoDummy;
+        if (i > 0) {
+            blockundo.vtxundo.push_back(CTxUndo());
+        }
+        UpdateCoins(tx, view, i == 0 ? undoDummy : blockundo.vtxundo.back(), pindex->nHeight);
+
+        vPos.push_back(std::make_pair(tx.GetHash(), pos));
+        pos.nTxOffset += ::GetSerializeSize(tx, SER_DISK, CLIENT_VERSION);
+    }
+    int64_t nTime3 = GetTimeMicros(); nTimeConnect += nTime3 - nTime2;
+    LogPrint("bench", "      - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) [%.2fs]\n", (unsigned)block.vtx.size(), 0.001 * (nTime3 - nTime2), 0.001 * (nTime3 - nTime2) / block.vtx.size(), nInputs <= 1 ? 0 : 0.001 * (nTime3 - nTime2) / (nInputs-1), nTimeConnect * 0.000001);
+
+    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, false);
+    int64_t nTime4 = GetTimeMicros(); nTimeVerify += nTime4 - nTime2;
+    LogPrint("bench", "    - Verify %u txins: %.2fms (%.3fms/txin) [%.2fs]\n", nInputs - 1, 0.001 * (nTime4 - nTime2), nInputs <= 1 ? 0 : 0.001 * (nTime4 - nTime2) / (nInputs-1), nTimeVerify * 0.000001);
+
+    if (fJustCheck)
+        return true;
+
+    // Write undo information to disk
+    if (pindex->GetUndoPos().IsNull() || !pindex->IsValid(BLOCK_VALID_SCRIPTS))
+    {
+        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;
+        }
+
+        pindex->RaiseValidity(BLOCK_VALID_SCRIPTS);
+        setDirtyBlockIndex.insert(pindex);
+    }
+
+    if (fTxIndex)
+        if (!pblocktree->WriteTxIndex(vPos))
+            return AbortNode(state, "Failed to write transaction index");
+
+    // add this block to the view's block chain
+    view.SetBestBlock(pindex->GetBlockHash());
+
+    int64_t nTime5 = GetTimeMicros(); nTimeIndex += nTime5 - nTime4;
+    LogPrint("bench", "    - Index writing: %.2fms [%.2fs]\n", 0.001 * (nTime5 - nTime4), nTimeIndex * 0.000001);
+
+    // Watch for changes to the previous coinbase transaction.
+    static uint256 hashPrevBestCoinBase;
+    GetMainSignals().UpdatedTransaction(hashPrevBestCoinBase);
+    hashPrevBestCoinBase = block.vtx[0]->GetHash();
+
+
+    int64_t nTime6 = GetTimeMicros(); nTimeCallbacks += nTime6 - nTime5;
+    LogPrint("bench", "    - Callbacks: %.2fms [%.2fs]\n", 0.001 * (nTime6 - nTime5), nTimeCallbacks * 0.000001);
+
+    return true;
+}
+
+/**
+ * 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(CValidationState &state, FlushStateMode mode) {
+    const CChainParams& chainparams = Params();
+    LOCK2(cs_main, cs_LastBlockFile);
+    static int64_t nLastWrite = 0;
+    static int64_t nLastFlush = 0;
+    static int64_t nLastSetChain = 0;
+    std::set<int> setFilesToPrune;
+    bool fFlushForPrune = false;
+    try {
+    if (fPruneMode && fCheckForPruning && !fReindex) {
+        FindFilesToPrune(setFilesToPrune, chainparams.PruneAfterHeight());
+        fCheckForPruning = false;
+        if (!setFilesToPrune.empty()) {
+            fFlushForPrune = true;
+            if (!fHavePruned) {
+                pblocktree->WriteFlag("prunedblockfiles", true);
+                fHavePruned = true;
+            }
+        }
+    }
+    int64_t nNow = GetTimeMicros();
+    // Avoid writing/flushing immediately after startup.
+    if (nLastWrite == 0) {
+        nLastWrite = nNow;
+    }
+    if (nLastFlush == 0) {
+        nLastFlush = nNow;
+    }
+    if (nLastSetChain == 0) {
+        nLastSetChain = nNow;
+    }
+    size_t cacheSize = pcoinsTip->DynamicMemoryUsage();
+    // The cache is large and close to the limit, but we have time now (not in the middle of a block processing).
+    bool fCacheLarge = mode == FLUSH_STATE_PERIODIC && cacheSize * (10.0/9) > nCoinCacheUsage;
+    // The cache is over the limit, we have to write now.
+    bool fCacheCritical = mode == FLUSH_STATE_IF_NEEDED && cacheSize > nCoinCacheUsage;
+    // 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.
+    bool 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 (set<int>::iterator it = setDirtyFileInfo.begin(); it != setDirtyFileInfo.end(); ) {
+                vFiles.push_back(make_pair(*it, &vinfoBlockFile[*it]));
+                setDirtyFileInfo.erase(it++);
+            }
+            std::vector<const CBlockIndex*> vBlocks;
+            vBlocks.reserve(setDirtyBlockIndex.size());
+            for (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, "Files 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) {
+        // Typical CCoins structures on disk are around 128 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(128 * 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;
+    FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
+}
+
+void PruneAndFlush() {
+    CValidationState state;
+    fCheckForPruning = true;
+    FlushStateToDisk(state, FLUSH_STATE_NONE);
+}
+
+/** Update chainActive and related internal data structures. */
+void static UpdateTip(CBlockIndex *pindexNew, const CChainParams& chainParams) {
+    chainActive.SetTip(pindexNew);
+
+    // New best block
+    mempool.AddTransactionsUpdated(1);
+
+    cvBlockChange.notify_all();
+
+    static bool fWarned = false;
+    std::vector<std::string> warningMessages;
+    if (!IsInitialBlockDownload())
+    {
+        int nUpgraded = 0;
+        const CBlockIndex* pindex = chainActive.Tip();
+        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) {
+                if (state == THRESHOLD_ACTIVE) {
+                    strMiscWarning = strprintf(_("Warning: unknown new rules activated (versionbit %i)"), bit);
+                    if (!fWarned) {
+                        AlertNotify(strMiscWarning);
+                        fWarned = true;
+                    }
+                } else {
+                    warningMessages.push_back(strprintf("unknown new rules are about to activate (versionbit %i)", bit));
+                }
+            }
+        }
+        // Check the version of the last 100 blocks to see if we need to upgrade:
+        for (int i = 0; i < 100 && pindex != NULL; i++)
+        {
+            int32_t nExpectedVersion = ComputeBlockVersion(pindex->pprev, chainParams.GetConsensus());
+            if (pindex->nVersion > VERSIONBITS_LAST_OLD_BLOCK_VERSION && (pindex->nVersion & ~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)
+        {
+            // strMiscWarning is read by GetWarnings(), called by Qt and the JSON-RPC code to warn the user:
+            strMiscWarning = _("Warning: Unknown block versions being mined! It's possible unknown rules are in effect");
+            if (!fWarned) {
+                AlertNotify(strMiscWarning);
+                fWarned = true;
+            }
+        }
+    }
+    LogPrintf("%s: new best=%s height=%d version=0x%08x log2_work=%.8g tx=%lu date='%s' progress=%f cache=%.1fMiB(%utx)", __func__,
+      chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(), chainActive.Tip()->nVersion,
+      log(chainActive.Tip()->nChainWork.getdouble())/log(2.0), (unsigned long)chainActive.Tip()->nChainTx,
+      DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
+      Checkpoints::GuessVerificationProgress(chainParams.Checkpoints(), chainActive.Tip()), pcoinsTip->DynamicMemoryUsage() * (1.0 / (1<<20)), pcoinsTip->GetCacheSize());
+    if (!warningMessages.empty())
+        LogPrintf(" warning='%s'", boost::algorithm::join(warningMessages, ", "));
+    LogPrintf("\n");
+
+}
+
+/** Disconnect chainActive's tip. You probably want to call mempool.removeForReorg and manually re-limit mempool size after this, with cs_main held. */
+bool static DisconnectTip(CValidationState& state, const CChainParams& chainparams, bool fBare = false)
+{
+    CBlockIndex *pindexDelete = chainActive.Tip();
+    assert(pindexDelete);
+    // Read block from disk.
+    CBlock block;
+    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);
+        if (!DisconnectBlock(block, state, pindexDelete, view))
+            return error("DisconnectTip(): DisconnectBlock %s failed", pindexDelete->GetBlockHash().ToString());
+        assert(view.Flush());
+    }
+    LogPrint("bench", "- Disconnect block: %.2fms\n", (GetTimeMicros() - nStart) * 0.001);
+    // Write the chain state to disk, if necessary.
+    if (!FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED))
+        return false;
+
+    if (!fBare) {
+        // Resurrect mempool transactions from the disconnected block.
+        std::vector<uint256> vHashUpdate;
+        for (const auto& it : block.vtx) {
+            const CTransaction& tx = *it;
+            // ignore validation errors in resurrected transactions
+            CValidationState stateDummy;
+            if (tx.IsCoinBase() || !AcceptToMemoryPool(mempool, stateDummy, tx, false, NULL, true)) {
+                mempool.removeRecursive(tx);
+            } else if (mempool.exists(tx.GetHash())) {
+                vHashUpdate.push_back(tx.GetHash());
+            }
+        }
+        // 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 this
+        // block that were added back and cleans up the mempool state.
+        mempool.UpdateTransactionsFromBlock(vHashUpdate);
+    }
+
+    // Update chainActive and related variables.
+    UpdateTip(pindexDelete->pprev, chainparams);
+    // Let wallets know transactions went from 1-confirmed to
+    // 0-confirmed or conflicted:
+    for (const auto& tx : block.vtx) {
+        GetMainSignals().SyncTransaction(*tx, pindexDelete->pprev, CMainSignals::SYNC_TRANSACTION_NOT_IN_BLOCK);
+    }
+    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;
+
+/**
+ * Connect a new block to chainActive. pblock is either NULL or a pointer to a CBlock
+ * corresponding to pindexNew, to bypass loading it again from disk.
+ */
+bool static ConnectTip(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexNew, const CBlock* pblock, std::vector<CTransactionRef> &txConflicted, std::vector<std::tuple<CTransactionRef,CBlockIndex*,int>> &txChanged)
+{
+    assert(pindexNew->pprev == chainActive.Tip());
+    // Read block from disk.
+    int64_t nTime1 = GetTimeMicros();
+    CBlock block;
+    if (!pblock) {
+        if (!ReadBlockFromDisk(block, pindexNew, chainparams.GetConsensus()))
+            return AbortNode(state, "Failed to read block");
+        pblock = &block;
+    }
+    // Apply the block atomically to the chain state.
+    int64_t nTime2 = GetTimeMicros(); nTimeReadFromDisk += nTime2 - nTime1;
+    int64_t nTime3;
+    LogPrint("bench", "  - Load block from disk: %.2fms [%.2fs]\n", (nTime2 - nTime1) * 0.001, nTimeReadFromDisk * 0.000001);
+    {
+        CCoinsViewCache view(pcoinsTip);
+        bool rv = ConnectBlock(*pblock, state, pindexNew, view, chainparams);
+        GetMainSignals().BlockChecked(*pblock, state);
+        if (!rv) {
+            if (state.IsInvalid())
+                InvalidBlockFound(pindexNew, state);
+            return error("ConnectTip(): ConnectBlock %s failed", pindexNew->GetBlockHash().ToString());
+        }
+        nTime3 = GetTimeMicros(); nTimeConnectTotal += nTime3 - nTime2;
+        LogPrint("bench", "  - Connect total: %.2fms [%.2fs]\n", (nTime3 - nTime2) * 0.001, nTimeConnectTotal * 0.000001);
+        assert(view.Flush());
+    }
+    int64_t nTime4 = GetTimeMicros(); nTimeFlush += nTime4 - nTime3;
+    LogPrint("bench", "  - Flush: %.2fms [%.2fs]\n", (nTime4 - nTime3) * 0.001, nTimeFlush * 0.000001);
+    // Write the chain state to disk, if necessary.
+    if (!FlushStateToDisk(state, FLUSH_STATE_IF_NEEDED))
+        return false;
+    int64_t nTime5 = GetTimeMicros(); nTimeChainState += nTime5 - nTime4;
+    LogPrint("bench", "  - Writing chainstate: %.2fms [%.2fs]\n", (nTime5 - nTime4) * 0.001, nTimeChainState * 0.000001);
+    // Remove conflicting transactions from the mempool.;
+    mempool.removeForBlock(pblock->vtx, pindexNew->nHeight, &txConflicted, !IsInitialBlockDownload());
+    // Update chainActive & related variables.
+    UpdateTip(pindexNew, chainparams);
+
+    for (unsigned int i=0; i < pblock->vtx.size(); i++)
+        txChanged.emplace_back(pblock->vtx[i], pindexNew, i);
+
+    int64_t nTime6 = GetTimeMicros(); nTimePostConnect += nTime6 - nTime5; nTimeTotal += nTime6 - nTime1;
+    LogPrint("bench", "  - Connect postprocess: %.2fms [%.2fs]\n", (nTime6 - nTime5) * 0.001, nTimePostConnect * 0.000001);
+    LogPrint("bench", "- Connect block: %.2fms [%.2fs]\n", (nTime6 - nTime1) * 0.001, nTimeTotal * 0.000001);
+    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).
+ */
+static CBlockIndex* FindMostWorkChain() {
+    do {
+        CBlockIndex *pindexNew = NULL;
+
+        // Find the best candidate header.
+        {
+            std::set<CBlockIndex*, CBlockIndexWorkComparator>::reverse_iterator it = setBlockIndexCandidates.rbegin();
+            if (it == setBlockIndexCandidates.rend())
+                return NULL;
+            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 == NULL || 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. */
+static void 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 NULL or a pointer to a CBlock corresponding to pindexMostWork.
+ */
+static bool ActivateBestChainStep(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexMostWork, const CBlock* pblock, bool& fInvalidFound, std::vector<CTransactionRef>& txConflicted, std::vector<std::tuple<CTransactionRef,CBlockIndex*,int>>& txChanged)
+{
+    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;
+    while (chainActive.Tip() && chainActive.Tip() != pindexFork) {
+        if (!DisconnectTip(state, chainparams))
+            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.
+        BOOST_REVERSE_FOREACH(CBlockIndex *pindexConnect, vpindexToConnect) {
+            if (!ConnectTip(state, chainparams, pindexConnect, pindexConnect == pindexMostWork ? pblock : NULL, txConflicted, txChanged)) {
+                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, ...).
+                    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) {
+        mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
+        LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
+    }
+    mempool.check(pcoinsTip);
+
+    // 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 = NULL;
+    CBlockIndex* pindexHeader = NULL;
+    {
+        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 NULL or a pointer to a block
+ * that is already loaded (to avoid loading it again from disk).
+ */
+bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams, const CBlock *pblock) {
+    CBlockIndex *pindexMostWork = NULL;
+    CBlockIndex *pindexNewTip = NULL;
+    std::vector<std::tuple<CTransactionRef,CBlockIndex*,int>> txChanged;
+    if (pblock)
+        txChanged.reserve(pblock->vtx.size());
+    do {
+        txChanged.clear();
+        boost::this_thread::interruption_point();
+        if (ShutdownRequested())
+            break;
+
+        const CBlockIndex *pindexFork;
+        std::vector<CTransactionRef> txConflicted;
+        bool fInitialDownload;
+        {
+            LOCK(cs_main);
+            CBlockIndex *pindexOldTip = chainActive.Tip();
+            if (pindexMostWork == NULL) {
+                pindexMostWork = FindMostWorkChain();
+            }
+
+            // Whether we have anything to do at all.
+            if (pindexMostWork == NULL || pindexMostWork == chainActive.Tip())
+                return true;
+
+            bool fInvalidFound = false;
+            if (!ActivateBestChainStep(state, chainparams, pindexMostWork, pblock && pblock->GetHash() == pindexMostWork->GetBlockHash() ? pblock : NULL, fInvalidFound, txConflicted, txChanged))
+                return false;
+
+            if (fInvalidFound) {
+                // Wipe cache, we may need another branch now.
+                pindexMostWork = NULL;
+            }
+            pindexNewTip = chainActive.Tip();
+            pindexFork = chainActive.FindFork(pindexOldTip);
+            fInitialDownload = IsInitialBlockDownload();
+        }
+        // When we reach this point, we switched to a new tip (stored in pindexNewTip).
+
+        // Notifications/callbacks that can run without cs_main
+
+        // throw all transactions though the signal-interface
+        // while _not_ holding the cs_main lock
+        for (const auto& tx : txConflicted)
+        {
+            GetMainSignals().SyncTransaction(*tx, pindexNewTip, CMainSignals::SYNC_TRANSACTION_NOT_IN_BLOCK);
+        }
+        // ... and about transactions that got confirmed:
+        for (unsigned int i = 0; i < txChanged.size(); i++)
+            GetMainSignals().SyncTransaction(*std::get<0>(txChanged[i]), std::get<1>(txChanged[i]), std::get<2>(txChanged[i]));
+
+        // Notify external listeners about the new tip.
+        GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload);
+
+        // Always notify the UI if a new block tip was connected
+        if (pindexFork != pindexNewTip) {
+            uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
+        }
+    } while (pindexNewTip != pindexMostWork);
+    CheckBlockIndex(chainparams.GetConsensus());
+
+    // Write changes periodically to disk, after relay.
+    if (!FlushStateToDisk(state, FLUSH_STATE_PERIODIC)) {
+        return false;
+    }
+
+    return true;
+}
+
+
+bool 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);
+}
+
+bool InvalidateBlock(CValidationState& state, const CChainParams& chainparams, CBlockIndex *pindex)
+{
+    AssertLockHeld(cs_main);
+
+    // Mark the block itself as invalid.
+    pindex->nStatus |= BLOCK_FAILED_VALID;
+    setDirtyBlockIndex.insert(pindex);
+    setBlockIndexCandidates.erase(pindex);
+
+    while (chainActive.Contains(pindex)) {
+        CBlockIndex *pindexWalk = chainActive.Tip();
+        pindexWalk->nStatus |= BLOCK_FAILED_CHILD;
+        setDirtyBlockIndex.insert(pindexWalk);
+        setBlockIndexCandidates.erase(pindexWalk);
+        // ActivateBestChain considers blocks already in chainActive
+        // unconditionally valid already, so force disconnect away from it.
+        if (!DisconnectTip(state, chainparams)) {
+            mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
+            return false;
+        }
+    }
+
+    LimitMempoolSize(mempool, GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000, GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60);
+
+    // 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);
+    mempool.removeForReorg(pcoinsTip, chainActive.Tip()->nHeight + 1, STANDARD_LOCKTIME_VERIFY_FLAGS);
+    uiInterface.NotifyBlockTip(IsInitialBlockDownload(), pindex->pprev);
+    return true;
+}
+
+bool 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 = NULL;
+            }
+        }
+        it++;
+    }
+
+    // Remove the invalidity flag from all ancestors too.
+    while (pindex != NULL) {
+        if (pindex->nStatus & BLOCK_FAILED_MASK) {
+            pindex->nStatus &= ~BLOCK_FAILED_MASK;
+            setDirtyBlockIndex.insert(pindex);
+        }
+        pindex = pindex->pprev;
+    }
+    return true;
+}
+
+CBlockIndex* 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);
+    assert(pindexNew);
+    // 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(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->nChainWork = (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) + GetBlockProof(*pindexNew);
+    pindexNew->RaiseValidity(BLOCK_VALID_TREE);
+    if (pindexBestHeader == NULL || 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 ReceivedBlockTransactions(const CBlock &block, CValidationState& state, CBlockIndex *pindexNew, const CDiskBlockPos& pos)
+{
+    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, Params().GetConsensus())) {
+        pindexNew->nStatus |= BLOCK_OPT_WITNESS;
+    }
+    pindexNew->RaiseValidity(BLOCK_VALID_TRANSACTIONS);
+    setDirtyBlockIndex.insert(pindexNew);
+
+    if (pindexNew->pprev == NULL || pindexNew->pprev->nChainTx) {
+        // If pindexNew is the genesis block or all parents are BLOCK_VALID_TRANSACTIONS.
+        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() == NULL || !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;
+}
+
+bool FindBlockPos(CValidationState &state, 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 state.Error("out of disk space");
+        }
+    }
+
+    setDirtyFileInfo.insert(nFile);
+    return true;
+}
+
+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;
+}
+
+bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW)
+{
+    // Check proof of work matches claimed amount
+    if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
+        return state.DoS(50, false, REJECT_INVALID, "high-hash", false, "proof of work failed");
+
+    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() > MAX_BLOCK_BASE_SIZE || ::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS) > MAX_BLOCK_BASE_SIZE)
+        return state.DoS(100, false, REJECT_INVALID, "bad-blk-length", false, "size limits failed");
+
+    // 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
+    for (const auto& tx : block.vtx)
+        if (!CheckTransaction(*tx, state, false))
+            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;
+
+    return true;
+}
+
+static bool CheckIndexAgainstCheckpoint(const CBlockIndex* pindexPrev, CValidationState& state, const CChainParams& chainparams, const uint256& hash)
+{
+    if (*pindexPrev->phashBlock == chainparams.GetConsensus().hashGenesisBlock)
+        return true;
+
+    int nHeight = pindexPrev->nHeight+1;
+    // Don't accept any forks from the main chain prior to last checkpoint
+    CBlockIndex* pcheckpoint = Checkpoints::GetLastCheckpoint(chainparams.Checkpoints());
+    if (pcheckpoint && nHeight < pcheckpoint->nHeight)
+        return state.DoS(100, error("%s: forked chain older than last checkpoint (height %d)", __func__, nHeight));
+
+    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;
+    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]->wit.IsEmpty()) {
+        CMutableTransaction tx(*block.vtx[0]);
+        tx.wit.vtxinwit.resize(1);
+        tx.wit.vtxinwit[0].scriptWitness.stack.resize(1);
+        tx.wit.vtxinwit[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, NULL);
+            CHash256().Write(witnessroot.begin(), 32).Write(&ret[0], 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());
+            const_cast<std::vector<CTxOut>*>(&block.vtx[0]->vout)->push_back(out);
+            block.vtx[0]->UpdateHash();
+        }
+    }
+    UpdateUncommittedBlockStructures(block, pindexPrev, consensusParams);
+    return commitment;
+}
+
+bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev, int64_t nAdjustedTime)
+{
+    const int nHeight = pindexPrev == NULL ? 0 : pindexPrev->nHeight + 1;
+    // 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 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 + 2 * 60 * 60)
+        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.nVersion < 2 && nHeight >= consensusParams.BIP34Height) ||
+       (block.nVersion < 3 && nHeight >= consensusParams.BIP66Height) ||
+       (block.nVersion < 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;
+}
+
+bool ContextualCheckBlock(const CBlock& block, CValidationState& state, const Consensus::Params& consensusParams, const CBlockIndex* pindexPrev)
+{
+    const int nHeight = pindexPrev == NULL ? 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]->wit.vtxinwit.size() != 1 || block.vtx[0]->wit.vtxinwit[0].scriptWitness.stack.size() != 1 || block.vtx[0]->wit.vtxinwit[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]->wit.vtxinwit[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 (size_t i = 0; i < block.vtx.size(); i++) {
+            if (!block.vtx[i]->wit.IsNull()) {
+                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;
+}
+
+static bool 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 = NULL;
+    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)
+                return state.Invalid(error("%s: block %s is marked invalid", __func__, hash.ToString()), 0, "duplicate");
+            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 = NULL;
+        BlockMap::iterator mi = mapBlockIndex.find(block.hashPrevBlock);
+        if (mi == mapBlockIndex.end())
+            return state.DoS(10, error("%s: prev block not found", __func__), 0, "bad-prevblk");
+        pindexPrev = (*mi).second;
+        if (pindexPrev->nStatus & BLOCK_FAILED_MASK)
+            return state.DoS(100, error("%s: prev block invalid", __func__), REJECT_INVALID, "bad-prevblk");
+
+        assert(pindexPrev);
+        if (fCheckpointsEnabled && !CheckIndexAgainstCheckpoint(pindexPrev, state, chainparams, hash))
+            return error("%s: CheckIndexAgainstCheckpoint(): %s", __func__, state.GetRejectReason().c_str());
+
+        if (!ContextualCheckBlockHeader(block, state, chainparams.GetConsensus(), pindexPrev, GetAdjustedTime()))
+            return error("%s: Consensus::ContextualCheckBlockHeader: %s, %s", __func__, hash.ToString(), FormatStateMessage(state));
+    }
+    if (pindex == NULL)
+        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, CBlockIndex** ppindex)
+{
+    {
+        LOCK(cs_main);
+        for (const CBlockHeader& header : headers) {
+            if (!AcceptBlockHeader(header, state, chainparams, ppindex)) {
+                return false;
+            }
+        }
+    }
+    NotifyHeaderTip();
+    return true;
+}
+
+/** Store block on disk. If dbp is non-NULL, the file is known to already reside on disk */
+static bool AcceptBlock(const CBlock& block, CValidationState& state, const CChainParams& chainparams, CBlockIndex** ppindex, bool fRequested, const CDiskBlockPos* dbp, bool* fNewBlock)
+{
+    if (fNewBlock) *fNewBlock = false;
+    AssertLockHeld(cs_main);
+
+    CBlockIndex *pindexDummy = NULL;
+    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 fHasMoreWork = (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 datastructure 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 (!fHasMoreWork) return true;     // Don't process less-work chains
+        if (fTooFarAhead) return true;      // Block height is too high
+    }
+    if (fNewBlock) *fNewBlock = true;
+
+    if (!CheckBlock(block, state, chainparams.GetConsensus(), GetAdjustedTime()) ||
+        !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));
+    }
+
+    int nHeight = pindex->nHeight;
+
+    // Write block to history file
+    try {
+        unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
+        CDiskBlockPos blockPos;
+        if (dbp != NULL)
+            blockPos = *dbp;
+        if (!FindBlockPos(state, blockPos, nBlockSize+8, nHeight, block.GetBlockTime(), dbp != NULL))
+            return error("AcceptBlock(): FindBlockPos failed");
+        if (dbp == NULL)
+            if (!WriteBlockToDisk(block, blockPos, chainparams.MessageStart()))
+                AbortNode(state, "Failed to write block");
+        if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
+            return error("AcceptBlock(): ReceivedBlockTransactions failed");
+    } catch (const std::runtime_error& e) {
+        return AbortNode(state, std::string("System error: ") + e.what());
+    }
+
+    if (fCheckForPruning)
+        FlushStateToDisk(state, FLUSH_STATE_NONE); // we just allocated more disk space for block files
+
+    return true;
+}
+
+bool ProcessNewBlock(const CChainParams& chainparams, const CBlock* pblock, bool fForceProcessing, const CDiskBlockPos* dbp, bool *fNewBlock)
+{
+    {
+        LOCK(cs_main);
+
+        // Store to disk
+        CBlockIndex *pindex = NULL;
+        if (fNewBlock) *fNewBlock = false;
+        CValidationState state;
+        bool ret = AcceptBlock(*pblock, state, chainparams, &pindex, fForceProcessing, dbp, fNewBlock);
+        CheckBlockIndex(chainparams.GetConsensus());
+        if (!ret) {
+            GetMainSignals().BlockChecked(*pblock, state);
+            return error("%s: AcceptBlock FAILED", __func__);
+        }
+    }
+
+    NotifyHeaderTip();
+
+    CValidationState state; // Only used to report errors, not invalidity - ignore it
+    if (!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());
+    if (fCheckpointsEnabled && !CheckIndexAgainstCheckpoint(pindexPrev, state, chainparams, block.GetHash()))
+        return error("%s: CheckIndexAgainstCheckpoint(): %s", __func__, state.GetRejectReason().c_str());
+
+    CCoinsViewCache viewNew(pcoinsTip);
+    CBlockIndex indexDummy(block);
+    indexDummy.pprev = pindexPrev;
+    indexDummy.nHeight = pindexPrev->nHeight + 1;
+
+    // NOTE: CheckBlockHeader is called by CheckBlock
+    if (!ContextualCheckBlockHeader(block, state, chainparams.GetConsensus(), 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 (!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()
+{
+    uint64_t retval = 0;
+    BOOST_FOREACH(const CBlockFileInfo &file, vinfoBlockFile) {
+        retval += file.nSize + file.nUndoSize;
+    }
+    return retval;
+}
+
+/* Prune a block file (modify associated database entries)*/
+void PruneOneBlockFile(const int fileNumber)
+{
+    for (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); ++it) {
+        CBlockIndex* pindex = it->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(std::set<int>& setFilesToPrune)
+{
+    for (set<int>::iterator it = setFilesToPrune.begin(); it != setFilesToPrune.end(); ++it) {
+        CDiskBlockPos pos(*it, 0);
+        boost::filesystem::remove(GetBlockPosFilename(pos, "blk"));
+        boost::filesystem::remove(GetBlockPosFilename(pos, "rev"));
+        LogPrintf("Prune: %s deleted blk/rev (%05u)\n", __func__, *it);
+    }
+}
+
+/* Calculate the block/rev files that should be deleted to remain under target*/
+void FindFilesToPrune(std::set<int>& setFilesToPrune, uint64_t nPruneAfterHeight)
+{
+    LOCK2(cs_main, cs_LastBlockFile);
+    if (chainActive.Tip() == NULL || 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("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 = boost::filesystem::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;
+}
+
+FILE* OpenDiskFile(const CDiskBlockPos &pos, const char *prefix, bool fReadOnly)
+{
+    if (pos.IsNull())
+        return NULL;
+    boost::filesystem::path path = GetBlockPosFilename(pos, prefix);
+    boost::filesystem::create_directories(path.parent_path());
+    FILE* file = fopen(path.string().c_str(), "rb+");
+    if (!file && !fReadOnly)
+        file = fopen(path.string().c_str(), "wb+");
+    if (!file) {
+        LogPrintf("Unable to open file %s\n", path.string());
+        return NULL;
+    }
+    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 NULL;
+        }
+    }
+    return file;
+}
+
+FILE* OpenBlockFile(const CDiskBlockPos &pos, bool fReadOnly) {
+    return OpenDiskFile(pos, "blk", fReadOnly);
+}
+
+FILE* OpenUndoFile(const CDiskBlockPos &pos, bool fReadOnly) {
+    return OpenDiskFile(pos, "rev", fReadOnly);
+}
+
+boost::filesystem::path GetBlockPosFilename(const CDiskBlockPos &pos, const char *prefix)
+{
+    return GetDataDir() / "blocks" / strprintf("%s%05u.dat", prefix, pos.nFile);
+}
+
+CBlockIndex * InsertBlockIndex(uint256 hash)
+{
+    if (hash.IsNull())
+        return NULL;
+
+    // Return existing
+    BlockMap::iterator mi = mapBlockIndex.find(hash);
+    if (mi != mapBlockIndex.end())
+        return (*mi).second;
+
+    // Create new
+    CBlockIndex* pindexNew = new CBlockIndex();
+    if (!pindexNew)
+        throw runtime_error(std::string(__func__) + ": new CBlockIndex failed");
+    mi = mapBlockIndex.insert(make_pair(hash, pindexNew)).first;
+    pindexNew->phashBlock = &((*mi).first);
+
+    return pindexNew;
+}
+
+bool static LoadBlockIndexDB(const CChainParams& chainparams)
+{
+    if (!pblocktree->LoadBlockIndexGuts(InsertBlockIndex))
+        return false;
+
+    boost::this_thread::interruption_point();
+
+    // Calculate nChainWork
+    vector<pair<int, CBlockIndex*> > vSortedByHeight;
+    vSortedByHeight.reserve(mapBlockIndex.size());
+    BOOST_FOREACH(const PAIRTYPE(uint256, CBlockIndex*)& item, mapBlockIndex)
+    {
+        CBlockIndex* pindex = item.second;
+        vSortedByHeight.push_back(make_pair(pindex->nHeight, pindex));
+    }
+    sort(vSortedByHeight.begin(), vSortedByHeight.end());
+    BOOST_FOREACH(const PAIRTYPE(int, CBlockIndex*)& item, vSortedByHeight)
+    {
+        CBlockIndex* pindex = item.second;
+        pindex->nChainWork = (pindex->pprev ? pindex->pprev->nChainWork : 0) + GetBlockProof(*pindex);
+        // 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->IsValid(BLOCK_VALID_TRANSACTIONS) && (pindex->nChainTx || pindex->pprev == NULL))
+            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 == NULL || CBlockIndexWorkComparator()(pindexBestHeader, pindex)))
+            pindexBestHeader = pindex;
+    }
+
+    // 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");
+    set<int> setBlkDataFiles;
+    BOOST_FOREACH(const PAIRTYPE(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);
+    fReindex |= fReindexing;
+
+    // Check whether we have a transaction index
+    pblocktree->ReadFlag("txindex", fTxIndex);
+    LogPrintf("%s: transaction index %s\n", __func__, fTxIndex ? "enabled" : "disabled");
+
+    // Load pointer to end of best chain
+    BlockMap::iterator it = mapBlockIndex.find(pcoinsTip->GetBestBlock());
+    if (it == mapBlockIndex.end())
+        return true;
+    chainActive.SetTip(it->second);
+
+    PruneBlockIndexCandidates();
+
+    LogPrintf("%s: hashBestChain=%s height=%d date=%s progress=%f\n", __func__,
+        chainActive.Tip()->GetBlockHash().ToString(), chainActive.Height(),
+        DateTimeStrFormat("%Y-%m-%d %H:%M:%S", chainActive.Tip()->GetBlockTime()),
+        Checkpoints::GuessVerificationProgress(chainparams.Checkpoints(), chainActive.Tip()));
+
+    return true;
+}
+
+CVerifyDB::CVerifyDB()
+{
+    uiInterface.ShowProgress(_("Verifying blocks..."), 0);
+}
+
+CVerifyDB::~CVerifyDB()
+{
+    uiInterface.ShowProgress("", 100);
+}
+
+bool CVerifyDB::VerifyDB(const CChainParams& chainparams, CCoinsView *coinsview, int nCheckLevel, int nCheckDepth)
+{
+    LOCK(cs_main);
+    if (chainActive.Tip() == NULL || chainActive.Tip()->pprev == NULL)
+        return true;
+
+    // Verify blocks in the best chain
+    if (nCheckDepth <= 0)
+        nCheckDepth = 1000000000; // suffices until the year 19000
+    if (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 = NULL;
+    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);
+        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;
+            CDiskBlockPos pos = pindex->GetUndoPos();
+            if (!pos.IsNull()) {
+                if (!UndoReadFromDisk(undo, pos, pindex->pprev->GetBlockHash()))
+                    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) {
+            bool fClean = true;
+            if (!DisconnectBlock(block, state, pindex, coins, &fClean))
+                return error("VerifyDB(): *** irrecoverable inconsistency in block data at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
+            pindexState = pindex->pprev;
+            if (!fClean) {
+                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))));
+            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 (!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;
+}
+
+bool RewindBlockIndex(const CChainParams& params)
+{
+    LOCK(cs_main);
+
+    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, true)) {
+            return error("RewindBlockIndex: unable to disconnect block at height %i", pindex->nHeight);
+        }
+        // Occasionally flush state to disk.
+        if (!FlushStateToDisk(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 (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); it++) {
+        CBlockIndex* pindexIter = it->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);
+        }
+    }
+
+    PruneBlockIndexCandidates();
+
+    CheckBlockIndex(params.GetConsensus());
+
+    if (!FlushStateToDisk(state, FLUSH_STATE_ALWAYS)) {
+        return false;
+    }
+
+    return true;
+}
+
+// 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);
+    setBlockIndexCandidates.clear();
+    chainActive.SetTip(NULL);
+    pindexBestInvalid = NULL;
+    pindexBestHeader = NULL;
+    mempool.clear();
+    mapBlocksUnlinked.clear();
+    vinfoBlockFile.clear();
+    nLastBlockFile = 0;
+    nBlockSequenceId = 1;
+    setDirtyBlockIndex.clear();
+    setDirtyFileInfo.clear();
+    versionbitscache.Clear();
+    for (int b = 0; b < VERSIONBITS_NUM_BITS; b++) {
+        warningcache[b].clear();
+    }
+
+    BOOST_FOREACH(BlockMap::value_type& entry, mapBlockIndex) {
+        delete entry.second;
+    }
+    mapBlockIndex.clear();
+    fHavePruned = false;
+}
+
+bool LoadBlockIndex(const CChainParams& chainparams)
+{
+    // Load block index from databases
+    if (!fReindex && !LoadBlockIndexDB(chainparams))
+        return false;
+    return true;
+}
+
+bool InitBlockIndex(const CChainParams& chainparams) 
+{
+    LOCK(cs_main);
+
+    // Check whether we're already initialized
+    if (chainActive.Genesis() != NULL)
+        return true;
+
+    // Use the provided setting for -txindex in the new database
+    fTxIndex = GetBoolArg("-txindex", DEFAULT_TXINDEX);
+    pblocktree->WriteFlag("txindex", fTxIndex);
+    LogPrintf("Initializing databases...\n");
+
+    // Only add the genesis block if not reindexing (in which case we reuse the one already on disk)
+    if (!fReindex) {
+        try {
+            CBlock &block = const_cast<CBlock&>(chainparams.GenesisBlock());
+            // Start new block file
+            unsigned int nBlockSize = ::GetSerializeSize(block, SER_DISK, CLIENT_VERSION);
+            CDiskBlockPos blockPos;
+            CValidationState state;
+            if (!FindBlockPos(state, blockPos, nBlockSize+8, 0, block.GetBlockTime()))
+                return error("LoadBlockIndex(): FindBlockPos failed");
+            if (!WriteBlockToDisk(block, blockPos, chainparams.MessageStart()))
+                return error("LoadBlockIndex(): writing genesis block to disk failed");
+            CBlockIndex *pindex = AddToBlockIndex(block);
+            if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
+                return error("LoadBlockIndex(): genesis block not accepted");
+            // Force a chainstate write so that when we VerifyDB in a moment, it doesn't check stale data
+            return FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
+        } catch (const std::runtime_error& e) {
+            return error("LoadBlockIndex(): failed to initialize block database: %s", e.what());
+        }
+    }
+
+    return true;
+}
+
+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);
+                CBlock block;
+                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("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 (AcceptBlock(block, state, chainparams, NULL, true, dbp, NULL))
+                        nLoaded++;
+                    if (state.IsError())
+                        break;
+                } else if (hash != chainparams.GetConsensus().hashGenesisBlock && mapBlockIndex[hash]->nHeight % 1000 == 0) {
+                    LogPrint("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
+                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;
+                        if (ReadBlockFromDisk(block, it->second, chainparams.GetConsensus()))
+                        {
+                            LogPrint("reindex", "%s: Processing out of order child %s of %s\n", __func__, block.GetHash().ToString(),
+                                    head.ToString());
+                            LOCK(cs_main);
+                            CValidationState dummy;
+                            if (AcceptBlock(block, dummy, chainparams, NULL, true, &it->second, NULL))
+                            {
+                                nLoaded++;
+                                queue.push_back(block.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 static 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 (BlockMap::iterator it = mapBlockIndex.begin(); it != mapBlockIndex.end(); it++) {
+        forward.insert(std::make_pair(it->second->pprev, it->second));
+    }
+
+    assert(forward.size() == mapBlockIndex.size());
+
+    std::pair<std::multimap<CBlockIndex*,CBlockIndex*>::iterator,std::multimap<CBlockIndex*,CBlockIndex*>::iterator> rangeGenesis = forward.equal_range(NULL);
+    CBlockIndex *pindex = rangeGenesis.first->second;
+    rangeGenesis.first++;
+    assert(rangeGenesis.first == rangeGenesis.second); // There is only one index entry with parent NULL.
+
+    // 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 = NULL; // Oldest ancestor of pindex which is invalid.
+    CBlockIndex* pindexFirstMissing = NULL; // Oldest ancestor of pindex which does not have BLOCK_HAVE_DATA.
+    CBlockIndex* pindexFirstNeverProcessed = NULL; // Oldest ancestor of pindex for which nTx == 0.
+    CBlockIndex* pindexFirstNotTreeValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_TREE (regardless of being valid or not).
+    CBlockIndex* pindexFirstNotTransactionsValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_TRANSACTIONS (regardless of being valid or not).
+    CBlockIndex* pindexFirstNotChainValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_CHAIN (regardless of being valid or not).
+    CBlockIndex* pindexFirstNotScriptsValid = NULL; // Oldest ancestor of pindex which does not have BLOCK_VALID_SCRIPTS (regardless of being valid or not).
+    while (pindex != NULL) {
+        nNodes++;
+        if (pindexFirstInvalid == NULL && pindex->nStatus & BLOCK_FAILED_VALID) pindexFirstInvalid = pindex;
+        if (pindexFirstMissing == NULL && !(pindex->nStatus & BLOCK_HAVE_DATA)) pindexFirstMissing = pindex;
+        if (pindexFirstNeverProcessed == NULL && pindex->nTx == 0) pindexFirstNeverProcessed = pindex;
+        if (pindex->pprev != NULL && pindexFirstNotTreeValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TREE) pindexFirstNotTreeValid = pindex;
+        if (pindex->pprev != NULL && pindexFirstNotTransactionsValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_TRANSACTIONS) pindexFirstNotTransactionsValid = pindex;
+        if (pindex->pprev != NULL && pindexFirstNotChainValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_CHAIN) pindexFirstNotChainValid = pindex;
+        if (pindex->pprev != NULL && pindexFirstNotScriptsValid == NULL && (pindex->nStatus & BLOCK_VALID_MASK) < BLOCK_VALID_SCRIPTS) pindexFirstNotScriptsValid = pindex;
+
+        // Begin: actual consistency checks.
+        if (pindex->pprev == NULL) {
+            // 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 != NULL) == (pindex->nChainTx == 0)); // nChainTx != 0 is used to signal that all parent blocks have been processed (but may have been pruned).
+        assert((pindexFirstNotTransactionsValid != NULL) == (pindex->nChainTx == 0));
+        assert(pindex->nHeight == nHeight); // nHeight must be consistent.
+        assert(pindex->pprev == NULL || 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 == NULL); // All mapBlockIndex entries must at least be TREE valid
+        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_TREE) assert(pindexFirstNotTreeValid == NULL); // TREE valid implies all parents are TREE valid
+        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_CHAIN) assert(pindexFirstNotChainValid == NULL); // CHAIN valid implies all parents are CHAIN valid
+        if ((pindex->nStatus & BLOCK_VALID_MASK) >= BLOCK_VALID_SCRIPTS) assert(pindexFirstNotScriptsValid == NULL); // SCRIPTS valid implies all parents are SCRIPTS valid
+        if (pindexFirstInvalid == NULL) {
+            // 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 == NULL) {
+            if (pindexFirstInvalid == NULL) {
+                // 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 == NULL || 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 != NULL && pindexFirstInvalid == NULL) {
+            // 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 == NULL) assert(!foundInUnlinked); // We aren't missing data for any parent -- cannot be in mapBlocksUnlinked.
+        if (pindex->pprev && (pindex->nStatus & BLOCK_HAVE_DATA) && pindexFirstNeverProcessed == NULL && pindexFirstMissing != NULL) {
+            // 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 == NULL) {
+                    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 = NULL;
+            if (pindex == pindexFirstMissing) pindexFirstMissing = NULL;
+            if (pindex == pindexFirstNeverProcessed) pindexFirstNeverProcessed = NULL;
+            if (pindex == pindexFirstNotTreeValid) pindexFirstNotTreeValid = NULL;
+            if (pindex == pindexFirstNotTransactionsValid) pindexFirstNotTransactionsValid = NULL;
+            if (pindex == pindexFirstNotChainValid) pindexFirstNotChainValid = NULL;
+            if (pindex == pindexFirstNotScriptsValid) pindexFirstNotScriptsValid = NULL;
+            // 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 GetWarnings(const std::string& strFor)
+{
+    string strStatusBar;
+    string strRPC;
+    string strGUI;
+    const string uiAlertSeperator = "<hr />";
+
+    if (!CLIENT_VERSION_IS_RELEASE) {
+        strStatusBar = "This is a pre-release test build - use at your own risk - do not use for mining or merchant applications";
+        strGUI = _("This is a pre-release test build - use at your own risk - do not use for mining or merchant applications");
+    }
+
+    if (GetBoolArg("-testsafemode", DEFAULT_TESTSAFEMODE))
+        strStatusBar = strRPC = strGUI = "testsafemode enabled";
+
+    // Misc warnings like out of disk space and clock is wrong
+    if (strMiscWarning != "")
+    {
+        strStatusBar = strMiscWarning;
+        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + strMiscWarning;
+    }
+
+    if (fLargeWorkForkFound)
+    {
+        strStatusBar = strRPC = "Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.";
+        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + _("Warning: The network does not appear to fully agree! Some miners appear to be experiencing issues.");
+    }
+    else if (fLargeWorkInvalidChainFound)
+    {
+        strStatusBar = strRPC = "Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.";
+        strGUI += (strGUI.empty() ? "" : uiAlertSeperator) + _("Warning: We do not appear to fully agree with our peers! You may need to upgrade, or other nodes may need to upgrade.");
+    }
+
+    if (strFor == "gui")
+        return strGUI;
+    else if (strFor == "statusbar")
+        return strStatusBar;
+    else if (strFor == "rpc")
+        return strRPC;
+    assert(!"GetWarnings(): invalid parameter");
+    return "error";
+}
+ 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));
+ }
+
+ThresholdState VersionBitsTipState(const Consensus::Params& params, Consensus::DeploymentPos pos)
+{
+    LOCK(cs_main);
+    return VersionBitsState(chainActive.Tip(), params, pos, versionbitscache);
+}
+
+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)
+{
+    int64_t nExpiryTimeout = GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60;
+    FILE* filestr = fopen((GetDataDir() / "mempool.dat").string().c_str(), "r");
+    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 skipped = 0;
+    int64_t failed = 0;
+    int64_t nNow = GetTime();
+
+    try {
+        uint64_t version;
+        file >> version;
+        if (version != MEMPOOL_DUMP_VERSION) {
+            return false;
+        }
+        uint64_t num;
+        file >> num;
+        double prioritydummy = 0;
+        while (num--) {
+            CTransaction tx;
+            int64_t nTime;
+            int64_t nFeeDelta;
+            file >> tx;
+            file >> nTime;
+            file >> nFeeDelta;
+
+            CAmount amountdelta = nFeeDelta;
+            if (amountdelta) {
+                mempool.PrioritiseTransaction(tx.GetHash(), tx.GetHash().ToString(), prioritydummy, amountdelta);
+            }
+            CValidationState state;
+            if (nTime + nExpiryTimeout > nNow) {
+                LOCK(cs_main);
+                AcceptToMemoryPoolWithTime(mempool, state, tx, true, NULL, nTime);
+                if (state.IsValid()) {
+                    ++count;
+                } else {
+                    ++failed;
+                }
+            } else {
+                ++skipped;
+            }
+        }
+        std::map<uint256, CAmount> mapDeltas;
+        file >> mapDeltas;
+
+        for (const auto& i : mapDeltas) {
+            mempool.PrioritiseTransaction(i.first, i.first.ToString(), prioritydummy, 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 successes, %i failed, %i expired\n", count, failed, skipped);
+    return true;
+}
+
+void 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.first;
+        }
+        vinfo = mempool.infoAll();
+    }
+
+    int64_t mid = GetTimeMicros();
+
+    try {
+        FILE* filestr = fopen((GetDataDir() / "mempool.dat.new").string().c_str(), "w");
+        if (!filestr) {
+            return;
+        }
+
+        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)*0.000001, (last-mid)*0.000001);
+    } catch (const std::exception& e) {
+        LogPrintf("Failed to dump mempool: %s. Continuing anyway.\n", e.what());
+    }
+}
+
+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;