src/txmempool.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2016 The Bitcoin Core developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #include "txmempool.h"
   7
   8 #include "consensus/consensus.h"
   9 #include "consensus/tx_verify.h"
  10 #include "consensus/validation.h"
  11 #include "validation.h"
  12 #include "policy/policy.h"
  13 #include "policy/fees.h"
  14 #include "streams.h"
  15 #include "timedata.h"
  16 #include "util.h"
  17 #include "utilmoneystr.h"
  18 #include "utiltime.h"
  19
  20 CTxMemPoolEntry::CTxMemPoolEntry(const CTransactionRef& _tx, const CAmount& _nFee,
  21                                  int64_t _nTime, unsigned int _entryHeight,
  22                                  bool _spendsCoinbase, int64_t _sigOpsCost, LockPoints lp):
  23     tx(_tx), nFee(_nFee), nTime(_nTime), entryHeight(_entryHeight),
  24     spendsCoinbase(_spendsCoinbase), sigOpCost(_sigOpsCost), lockPoints(lp)
  25 {
  26     nTxWeight = GetTransactionWeight(*tx);
  27     nUsageSize = RecursiveDynamicUsage(*tx) + memusage::DynamicUsage(tx);
  28
  29     nCountWithDescendants = 1;
  30     nSizeWithDescendants = GetTxSize();
  31     nModFeesWithDescendants = nFee;
  32
  33     feeDelta = 0;
  34
  35     nCountWithAncestors = 1;
  36     nSizeWithAncestors = GetTxSize();
  37     nModFeesWithAncestors = nFee;
  38     nSigOpCostWithAncestors = sigOpCost;
  39 }
  40
  41 CTxMemPoolEntry::CTxMemPoolEntry(const CTxMemPoolEntry& other)
  42 {
  43     *this = other;
  44 }
  45
  46 void CTxMemPoolEntry::UpdateFeeDelta(int64_t newFeeDelta)
  47 {
  48     nModFeesWithDescendants += newFeeDelta - feeDelta;
  49     nModFeesWithAncestors += newFeeDelta - feeDelta;
  50     feeDelta = newFeeDelta;
  51 }
  52
  53 void CTxMemPoolEntry::UpdateLockPoints(const LockPoints& lp)
  54 {
  55     lockPoints = lp;
  56 }
  57
  58 size_t CTxMemPoolEntry::GetTxSize() const
  59 {
  60     return GetVirtualTransactionSize(nTxWeight, sigOpCost);
  61 }
  62
  63 // Update the given tx for any in-mempool descendants.
  64 // Assumes that setMemPoolChildren is correct for the given tx and all
  65 // descendants.
  66 void CTxMemPool::UpdateForDescendants(txiter updateIt, cacheMap &cachedDescendants, const std::set<uint256> &setExclude)
  67 {
  68     setEntries stageEntries, setAllDescendants;
  69     stageEntries = GetMemPoolChildren(updateIt);
  70
  71     while (!stageEntries.empty()) {
  72         const txiter cit = *stageEntries.begin();
  73         setAllDescendants.insert(cit);
  74         stageEntries.erase(cit);
  75         const setEntries &setChildren = GetMemPoolChildren(cit);
  76         BOOST_FOREACH(const txiter childEntry, setChildren) {
  77             cacheMap::iterator cacheIt = cachedDescendants.find(childEntry);
  78             if (cacheIt != cachedDescendants.end()) {
  79                 // We've already calculated this one, just add the entries for this set
  80                 // but don't traverse again.
  81                 BOOST_FOREACH(const txiter cacheEntry, cacheIt->second) {
  82                     setAllDescendants.insert(cacheEntry);
  83                 }
  84             } else if (!setAllDescendants.count(childEntry)) {
  85                 // Schedule for later processing
  86                 stageEntries.insert(childEntry);
  87             }
  88         }
  89     }
  90     // setAllDescendants now contains all in-mempool descendants of updateIt.
  91     // Update and add to cached descendant map
  92     int64_t modifySize = 0;
  93     CAmount modifyFee = 0;
  94     int64_t modifyCount = 0;
  95     BOOST_FOREACH(txiter cit, setAllDescendants) {
  96         if (!setExclude.count(cit->GetTx().GetHash())) {
  97             modifySize += cit->GetTxSize();
  98             modifyFee += cit->GetModifiedFee();
  99             modifyCount++;
 100             cachedDescendants[updateIt].insert(cit);
 101             // Update ancestor state for each descendant
 102             mapTx.modify(cit, update_ancestor_state(updateIt->GetTxSize(), updateIt->GetModifiedFee(), 1, updateIt->GetSigOpCost()));
 103         }
 104     }
 105     mapTx.modify(updateIt, update_descendant_state(modifySize, modifyFee, modifyCount));
 106 }
 107
 108 // vHashesToUpdate is the set of transaction hashes from a disconnected block
 109 // which has been re-added to the mempool.
 110 // for each entry, look for descendants that are outside vHashesToUpdate, and
 111 // add fee/size information for such descendants to the parent.
 112 // for each such descendant, also update the ancestor state to include the parent.
 113 void CTxMemPool::UpdateTransactionsFromBlock(const std::vector<uint256> &vHashesToUpdate)
 114 {
 115     LOCK(cs);
 116     // For each entry in vHashesToUpdate, store the set of in-mempool, but not
 117     // in-vHashesToUpdate transactions, so that we don't have to recalculate
 118     // descendants when we come across a previously seen entry.
 119     cacheMap mapMemPoolDescendantsToUpdate;
 120
 121     // Use a set for lookups into vHashesToUpdate (these entries are already
 122     // accounted for in the state of their ancestors)
 123     std::set<uint256> setAlreadyIncluded(vHashesToUpdate.begin(), vHashesToUpdate.end());
 124
 125     // Iterate in reverse, so that whenever we are looking at at a transaction
 126     // we are sure that all in-mempool descendants have already been processed.
 127     // This maximizes the benefit of the descendant cache and guarantees that
 128     // setMemPoolChildren will be updated, an assumption made in
 129     // UpdateForDescendants.
 130     BOOST_REVERSE_FOREACH(const uint256 &hash, vHashesToUpdate) {
 131         // we cache the in-mempool children to avoid duplicate updates
 132         setEntries setChildren;
 133         // calculate children from mapNextTx
 134         txiter it = mapTx.find(hash);
 135         if (it == mapTx.end()) {
 136             continue;
 137         }
 138         auto iter = mapNextTx.lower_bound(COutPoint(hash, 0));
 139         // First calculate the children, and update setMemPoolChildren to
 140         // include them, and update their setMemPoolParents to include this tx.
 141         for (; iter != mapNextTx.end() && iter->first->hash == hash; ++iter) {
 142             const uint256 &childHash = iter->second->GetHash();
 143             txiter childIter = mapTx.find(childHash);
 144             assert(childIter != mapTx.end());
 145             // We can skip updating entries we've encountered before or that
 146             // are in the block (which are already accounted for).
 147             if (setChildren.insert(childIter).second && !setAlreadyIncluded.count(childHash)) {
 148                 UpdateChild(it, childIter, true);
 149                 UpdateParent(childIter, it, true);
 150             }
 151         }
 152         UpdateForDescendants(it, mapMemPoolDescendantsToUpdate, setAlreadyIncluded);
 153     }
 154 }
 155
 156 bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntries &setAncestors, uint64_t limitAncestorCount, uint64_t limitAncestorSize, uint64_t limitDescendantCount, uint64_t limitDescendantSize, std::string &errString, bool fSearchForParents /* = true */) const
 157 {
 158     LOCK(cs);
 159
 160     setEntries parentHashes;
 161     const CTransaction &tx = entry.GetTx();
 162
 163     if (fSearchForParents) {
 164         // Get parents of this transaction that are in the mempool
 165         // GetMemPoolParents() is only valid for entries in the mempool, so we
 166         // iterate mapTx to find parents.
 167         for (unsigned int i = 0; i < tx.vin.size(); i++) {
 168             txiter piter = mapTx.find(tx.vin[i].prevout.hash);
 169             if (piter != mapTx.end()) {
 170                 parentHashes.insert(piter);
 171                 if (parentHashes.size() + 1 > limitAncestorCount) {
 172                     errString = strprintf("too many unconfirmed parents [limit: %u]", limitAncestorCount);
 173                     return false;
 174                 }
 175             }
 176         }
 177     } else {
 178         // If we're not searching for parents, we require this to be an
 179         // entry in the mempool already.
 180         txiter it = mapTx.iterator_to(entry);
 181         parentHashes = GetMemPoolParents(it);
 182     }
 183
 184     size_t totalSizeWithAncestors = entry.GetTxSize();
 185
 186     while (!parentHashes.empty()) {
 187         txiter stageit = *parentHashes.begin();
 188
 189         setAncestors.insert(stageit);
 190         parentHashes.erase(stageit);
 191         totalSizeWithAncestors += stageit->GetTxSize();
 192
 193         if (stageit->GetSizeWithDescendants() + entry.GetTxSize() > limitDescendantSize) {
 194             errString = strprintf("exceeds descendant size limit for tx %s [limit: %u]", stageit->GetTx().GetHash().ToString(), limitDescendantSize);
 195             return false;
 196         } else if (stageit->GetCountWithDescendants() + 1 > limitDescendantCount) {
 197             errString = strprintf("too many descendants for tx %s [limit: %u]", stageit->GetTx().GetHash().ToString(), limitDescendantCount);
 198             return false;
 199         } else if (totalSizeWithAncestors > limitAncestorSize) {
 200             errString = strprintf("exceeds ancestor size limit [limit: %u]", limitAncestorSize);
 201             return false;
 202         }
 203
 204         const setEntries & setMemPoolParents = GetMemPoolParents(stageit);
 205         BOOST_FOREACH(const txiter &phash, setMemPoolParents) {
 206             // If this is a new ancestor, add it.
 207             if (setAncestors.count(phash) == 0) {
 208                 parentHashes.insert(phash);
 209             }
 210             if (parentHashes.size() + setAncestors.size() + 1 > limitAncestorCount) {
 211                 errString = strprintf("too many unconfirmed ancestors [limit: %u]", limitAncestorCount);
 212                 return false;
 213             }
 214         }
 215     }
 216
 217     return true;
 218 }
 219
 220 void CTxMemPool::UpdateAncestorsOf(bool add, txiter it, setEntries &setAncestors)
 221 {
 222     setEntries parentIters = GetMemPoolParents(it);
 223     // add or remove this tx as a child of each parent
 224     BOOST_FOREACH(txiter piter, parentIters) {
 225         UpdateChild(piter, it, add);
 226     }
 227     const int64_t updateCount = (add ? 1 : -1);
 228     const int64_t updateSize = updateCount * it->GetTxSize();
 229     const CAmount updateFee = updateCount * it->GetModifiedFee();
 230     BOOST_FOREACH(txiter ancestorIt, setAncestors) {
 231         mapTx.modify(ancestorIt, update_descendant_state(updateSize, updateFee, updateCount));
 232     }
 233 }
 234
 235 void CTxMemPool::UpdateEntryForAncestors(txiter it, const setEntries &setAncestors)
 236 {
 237     int64_t updateCount = setAncestors.size();
 238     int64_t updateSize = 0;
 239     CAmount updateFee = 0;
 240     int64_t updateSigOpsCost = 0;
 241     BOOST_FOREACH(txiter ancestorIt, setAncestors) {
 242         updateSize += ancestorIt->GetTxSize();
 243         updateFee += ancestorIt->GetModifiedFee();
 244         updateSigOpsCost += ancestorIt->GetSigOpCost();
 245     }
 246     mapTx.modify(it, update_ancestor_state(updateSize, updateFee, updateCount, updateSigOpsCost));
 247 }
 248
 249 void CTxMemPool::UpdateChildrenForRemoval(txiter it)
 250 {
 251     const setEntries &setMemPoolChildren = GetMemPoolChildren(it);
 252     BOOST_FOREACH(txiter updateIt, setMemPoolChildren) {
 253         UpdateParent(updateIt, it, false);
 254     }
 255 }
 256
 257 void CTxMemPool::UpdateForRemoveFromMempool(const setEntries &entriesToRemove, bool updateDescendants)
 258 {
 259     // For each entry, walk back all ancestors and decrement size associated with this
 260     // transaction
 261     const uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
 262     if (updateDescendants) {
 263         // updateDescendants should be true whenever we're not recursively
 264         // removing a tx and all its descendants, eg when a transaction is
 265         // confirmed in a block.
 266         // Here we only update statistics and not data in mapLinks (which
 267         // we need to preserve until we're finished with all operations that
 268         // need to traverse the mempool).
 269         BOOST_FOREACH(txiter removeIt, entriesToRemove) {
 270             setEntries setDescendants;
 271             CalculateDescendants(removeIt, setDescendants);
 272             setDescendants.erase(removeIt); // don't update state for self
 273             int64_t modifySize = -((int64_t)removeIt->GetTxSize());
 274             CAmount modifyFee = -removeIt->GetModifiedFee();
 275             int modifySigOps = -removeIt->GetSigOpCost();
 276             BOOST_FOREACH(txiter dit, setDescendants) {
 277                 mapTx.modify(dit, update_ancestor_state(modifySize, modifyFee, -1, modifySigOps));
 278             }
 279         }
 280     }
 281     BOOST_FOREACH(txiter removeIt, entriesToRemove) {
 282         setEntries setAncestors;
 283         const CTxMemPoolEntry &entry = *removeIt;
 284         std::string dummy;
 285         // Since this is a tx that is already in the mempool, we can call CMPA
 286         // with fSearchForParents = false.  If the mempool is in a consistent
 287         // state, then using true or false should both be correct, though false
 288         // should be a bit faster.
 289         // However, if we happen to be in the middle of processing a reorg, then
 290         // the mempool can be in an inconsistent state.  In this case, the set
 291         // of ancestors reachable via mapLinks will be the same as the set of
 292         // ancestors whose packages include this transaction, because when we
 293         // add a new transaction to the mempool in addUnchecked(), we assume it
 294         // has no children, and in the case of a reorg where that assumption is
 295         // false, the in-mempool children aren't linked to the in-block tx's
 296         // until UpdateTransactionsFromBlock() is called.
 297         // So if we're being called during a reorg, ie before
 298         // UpdateTransactionsFromBlock() has been called, then mapLinks[] will
 299         // differ from the set of mempool parents we'd calculate by searching,
 300         // and it's important that we use the mapLinks[] notion of ancestor
 301         // transactions as the set of things to update for removal.
 302         CalculateMemPoolAncestors(entry, setAncestors, nNoLimit, nNoLimit, nNoLimit, nNoLimit, dummy, false);
 303         // Note that UpdateAncestorsOf severs the child links that point to
 304         // removeIt in the entries for the parents of removeIt.
 305         UpdateAncestorsOf(false, removeIt, setAncestors);
 306     }
 307     // After updating all the ancestor sizes, we can now sever the link between each
 308     // transaction being removed and any mempool children (ie, update setMemPoolParents
 309     // for each direct child of a transaction being removed).
 310     BOOST_FOREACH(txiter removeIt, entriesToRemove) {
 311         UpdateChildrenForRemoval(removeIt);
 312     }
 313 }
 314
 315 void CTxMemPoolEntry::UpdateDescendantState(int64_t modifySize, CAmount modifyFee, int64_t modifyCount)
 316 {
 317     nSizeWithDescendants += modifySize;
 318     assert(int64_t(nSizeWithDescendants) > 0);
 319     nModFeesWithDescendants += modifyFee;
 320     nCountWithDescendants += modifyCount;
 321     assert(int64_t(nCountWithDescendants) > 0);
 322 }
 323
 324 void CTxMemPoolEntry::UpdateAncestorState(int64_t modifySize, CAmount modifyFee, int64_t modifyCount, int modifySigOps)
 325 {
 326     nSizeWithAncestors += modifySize;
 327     assert(int64_t(nSizeWithAncestors) > 0);
 328     nModFeesWithAncestors += modifyFee;
 329     nCountWithAncestors += modifyCount;
 330     assert(int64_t(nCountWithAncestors) > 0);
 331     nSigOpCostWithAncestors += modifySigOps;
 332     assert(int(nSigOpCostWithAncestors) >= 0);
 333 }
 334
 335 CTxMemPool::CTxMemPool(CBlockPolicyEstimator* estimator) :
 336     nTransactionsUpdated(0), minerPolicyEstimator(estimator)
 337 {
 338     _clear(); //lock free clear
 339
 340     // Sanity checks off by default for performance, because otherwise
 341     // accepting transactions becomes O(N^2) where N is the number
 342     // of transactions in the pool
 343     nCheckFrequency = 0;
 344 }
 345
 346 void CTxMemPool::pruneSpent(const uint256 &hashTx, CCoins &coins)
 347 {
 348     LOCK(cs);
 349
 350     auto it = mapNextTx.lower_bound(COutPoint(hashTx, 0));
 351
 352     // iterate over all COutPoints in mapNextTx whose hash equals the provided hashTx
 353     while (it != mapNextTx.end() && it->first->hash == hashTx) {
 354         coins.Spend(it->first->n); // and remove those outputs from coins
 355         it++;
 356     }
 357 }
 358
 359 unsigned int CTxMemPool::GetTransactionsUpdated() const
 360 {
 361     LOCK(cs);
 362     return nTransactionsUpdated;
 363 }
 364
 365 void CTxMemPool::AddTransactionsUpdated(unsigned int n)
 366 {
 367     LOCK(cs);
 368     nTransactionsUpdated += n;
 369 }
 370
 371 bool CTxMemPool::addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry, setEntries &setAncestors, bool validFeeEstimate)
 372 {
 373     NotifyEntryAdded(entry.GetSharedTx());
 374     // Add to memory pool without checking anything.
 375     // Used by AcceptToMemoryPool(), which DOES do
 376     // all the appropriate checks.
 377     LOCK(cs);
 378     indexed_transaction_set::iterator newit = mapTx.insert(entry).first;
 379     mapLinks.insert(make_pair(newit, TxLinks()));
 380
 381     // Update transaction for any feeDelta created by PrioritiseTransaction
 382     // TODO: refactor so that the fee delta is calculated before inserting
 383     // into mapTx.
 384     std::map<uint256, CAmount>::const_iterator pos = mapDeltas.find(hash);
 385     if (pos != mapDeltas.end()) {
 386         const CAmount &delta = pos->second;
 387         if (delta) {
 388             mapTx.modify(newit, update_fee_delta(delta));
 389         }
 390     }
 391
 392     // Update cachedInnerUsage to include contained transaction's usage.
 393     // (When we update the entry for in-mempool parents, memory usage will be
 394     // further updated.)
 395     cachedInnerUsage += entry.DynamicMemoryUsage();
 396
 397     const CTransaction& tx = newit->GetTx();
 398     std::set<uint256> setParentTransactions;
 399     for (unsigned int i = 0; i < tx.vin.size(); i++) {
 400         mapNextTx.insert(std::make_pair(&tx.vin[i].prevout, &tx));
 401         setParentTransactions.insert(tx.vin[i].prevout.hash);
 402     }
 403     // Don't bother worrying about child transactions of this one.
 404     // Normal case of a new transaction arriving is that there can't be any
 405     // children, because such children would be orphans.
 406     // An exception to that is if a transaction enters that used to be in a block.
 407     // In that case, our disconnect block logic will call UpdateTransactionsFromBlock
 408     // to clean up the mess we're leaving here.
 409
 410     // Update ancestors with information about this tx
 411     BOOST_FOREACH (const uint256 &phash, setParentTransactions) {
 412         txiter pit = mapTx.find(phash);
 413         if (pit != mapTx.end()) {
 414             UpdateParent(newit, pit, true);
 415         }
 416     }
 417     UpdateAncestorsOf(true, newit, setAncestors);
 418     UpdateEntryForAncestors(newit, setAncestors);
 419
 420     nTransactionsUpdated++;
 421     totalTxSize += entry.GetTxSize();
 422     if (minerPolicyEstimator) {minerPolicyEstimator->processTransaction(entry, validFeeEstimate);}
 423
 424     vTxHashes.emplace_back(tx.GetWitnessHash(), newit);
 425     newit->vTxHashesIdx = vTxHashes.size() - 1;
 426
 427     return true;
 428 }
 429
 430 void CTxMemPool::removeUnchecked(txiter it, MemPoolRemovalReason reason)
 431 {
 432     NotifyEntryRemoved(it->GetSharedTx(), reason);
 433     const uint256 hash = it->GetTx().GetHash();
 434     BOOST_FOREACH(const CTxIn& txin, it->GetTx().vin)
 435         mapNextTx.erase(txin.prevout);
 436
 437     if (vTxHashes.size() > 1) {
 438         vTxHashes[it->vTxHashesIdx] = std::move(vTxHashes.back());
 439         vTxHashes[it->vTxHashesIdx].second->vTxHashesIdx = it->vTxHashesIdx;
 440         vTxHashes.pop_back();
 441         if (vTxHashes.size() * 2 < vTxHashes.capacity())
 442             vTxHashes.shrink_to_fit();
 443     } else
 444         vTxHashes.clear();
 445
 446     totalTxSize -= it->GetTxSize();
 447     cachedInnerUsage -= it->DynamicMemoryUsage();
 448     cachedInnerUsage -= memusage::DynamicUsage(mapLinks[it].parents) + memusage::DynamicUsage(mapLinks[it].children);
 449     mapLinks.erase(it);
 450     mapTx.erase(it);
 451     nTransactionsUpdated++;
 452     if (minerPolicyEstimator) {minerPolicyEstimator->removeTx(hash, false);}
 453 }
 454
 455 // Calculates descendants of entry that are not already in setDescendants, and adds to
 456 // setDescendants. Assumes entryit is already a tx in the mempool and setMemPoolChildren
 457 // is correct for tx and all descendants.
 458 // Also assumes that if an entry is in setDescendants already, then all
 459 // in-mempool descendants of it are already in setDescendants as well, so that we
 460 // can save time by not iterating over those entries.
 461 void CTxMemPool::CalculateDescendants(txiter entryit, setEntries &setDescendants)
 462 {
 463     setEntries stage;
 464     if (setDescendants.count(entryit) == 0) {
 465         stage.insert(entryit);
 466     }
 467     // Traverse down the children of entry, only adding children that are not
 468     // accounted for in setDescendants already (because those children have either
 469     // already been walked, or will be walked in this iteration).
 470     while (!stage.empty()) {
 471         txiter it = *stage.begin();
 472         setDescendants.insert(it);
 473         stage.erase(it);
 474
 475         const setEntries &setChildren = GetMemPoolChildren(it);
 476         BOOST_FOREACH(const txiter &childiter, setChildren) {
 477             if (!setDescendants.count(childiter)) {
 478                 stage.insert(childiter);
 479             }
 480         }
 481     }
 482 }
 483
 484 void CTxMemPool::removeRecursive(const CTransaction &origTx, MemPoolRemovalReason reason)
 485 {
 486     // Remove transaction from memory pool
 487     {
 488         LOCK(cs);
 489         setEntries txToRemove;
 490         txiter origit = mapTx.find(origTx.GetHash());
 491         if (origit != mapTx.end()) {
 492             txToRemove.insert(origit);
 493         } else {
 494             // When recursively removing but origTx isn't in the mempool
 495             // be sure to remove any children that are in the pool. This can
 496             // happen during chain re-orgs if origTx isn't re-accepted into
 497             // the mempool for any reason.
 498             for (unsigned int i = 0; i < origTx.vout.size(); i++) {
 499                 auto it = mapNextTx.find(COutPoint(origTx.GetHash(), i));
 500                 if (it == mapNextTx.end())
 501                     continue;
 502                 txiter nextit = mapTx.find(it->second->GetHash());
 503                 assert(nextit != mapTx.end());
 504                 txToRemove.insert(nextit);
 505             }
 506         }
 507         setEntries setAllRemoves;
 508         BOOST_FOREACH(txiter it, txToRemove) {
 509             CalculateDescendants(it, setAllRemoves);
 510         }
 511
 512         RemoveStaged(setAllRemoves, false, reason);
 513     }
 514 }
 515
 516 void CTxMemPool::removeForReorg(const CCoinsViewCache *pcoins, unsigned int nMemPoolHeight, int flags)
 517 {
 518     // Remove transactions spending a coinbase which are now immature and no-longer-final transactions
 519     LOCK(cs);
 520     setEntries txToRemove;
 521     for (indexed_transaction_set::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
 522         const CTransaction& tx = it->GetTx();
 523         LockPoints lp = it->GetLockPoints();
 524         bool validLP =  TestLockPointValidity(&lp);
 525         if (!CheckFinalTx(tx, flags) || !CheckSequenceLocks(tx, flags, &lp, validLP)) {
 526             // Note if CheckSequenceLocks fails the LockPoints may still be invalid
 527             // So it's critical that we remove the tx and not depend on the LockPoints.
 528             txToRemove.insert(it);
 529         } else if (it->GetSpendsCoinbase()) {
 530             BOOST_FOREACH(const CTxIn& txin, tx.vin) {
 531                 indexed_transaction_set::const_iterator it2 = mapTx.find(txin.prevout.hash);
 532                 if (it2 != mapTx.end())
 533                     continue;
 534                 const CCoins *coins = pcoins->AccessCoins(txin.prevout.hash);
 535                 if (nCheckFrequency != 0) assert(coins);
 536                 if (!coins || (coins->IsCoinBase() && ((signed long)nMemPoolHeight) - coins->nHeight < COINBASE_MATURITY)) {
 537                     txToRemove.insert(it);
 538                     break;
 539                 }
 540             }
 541         }
 542         if (!validLP) {
 543             mapTx.modify(it, update_lock_points(lp));
 544         }
 545     }
 546     setEntries setAllRemoves;
 547     for (txiter it : txToRemove) {
 548         CalculateDescendants(it, setAllRemoves);
 549     }
 550     RemoveStaged(setAllRemoves, false, MemPoolRemovalReason::REORG);
 551 }
 552
 553 void CTxMemPool::removeConflicts(const CTransaction &tx)
 554 {
 555     // Remove transactions which depend on inputs of tx, recursively
 556     LOCK(cs);
 557     BOOST_FOREACH(const CTxIn &txin, tx.vin) {
 558         auto it = mapNextTx.find(txin.prevout);
 559         if (it != mapNextTx.end()) {
 560             const CTransaction &txConflict = *it->second;
 561             if (txConflict != tx)
 562             {
 563                 ClearPrioritisation(txConflict.GetHash());
 564                 removeRecursive(txConflict, MemPoolRemovalReason::CONFLICT);
 565             }
 566         }
 567     }
 568 }
 569
 570 /**
 571  * Called when a block is connected. Removes from mempool and updates the miner fee estimator.
 572  */
 573 void CTxMemPool::removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight)
 574 {
 575     LOCK(cs);
 576     std::vector<const CTxMemPoolEntry*> entries;
 577     for (const auto& tx : vtx)
 578     {
 579         uint256 hash = tx->GetHash();
 580
 581         indexed_transaction_set::iterator i = mapTx.find(hash);
 582         if (i != mapTx.end())
 583             entries.push_back(&*i);
 584     }
 585     // Before the txs in the new block have been removed from the mempool, update policy estimates
 586     if (minerPolicyEstimator) {minerPolicyEstimator->processBlock(nBlockHeight, entries);}
 587     for (const auto& tx : vtx)
 588     {
 589         txiter it = mapTx.find(tx->GetHash());
 590         if (it != mapTx.end()) {
 591             setEntries stage;
 592             stage.insert(it);
 593             RemoveStaged(stage, true, MemPoolRemovalReason::BLOCK);
 594         }
 595         removeConflicts(*tx);
 596         ClearPrioritisation(tx->GetHash());
 597     }
 598     lastRollingFeeUpdate = GetTime();
 599     blockSinceLastRollingFeeBump = true;
 600 }
 601
 602 void CTxMemPool::_clear()
 603 {
 604     mapLinks.clear();
 605     mapTx.clear();
 606     mapNextTx.clear();
 607     totalTxSize = 0;
 608     cachedInnerUsage = 0;
 609     lastRollingFeeUpdate = GetTime();
 610     blockSinceLastRollingFeeBump = false;
 611     rollingMinimumFeeRate = 0;
 612     ++nTransactionsUpdated;
 613 }
 614
 615 void CTxMemPool::clear()
 616 {
 617     LOCK(cs);
 618     _clear();
 619 }
 620
 621 void CTxMemPool::check(const CCoinsViewCache *pcoins) const
 622 {
 623     if (nCheckFrequency == 0)
 624         return;
 625
 626     if (GetRand(std::numeric_limits<uint32_t>::max()) >= nCheckFrequency)
 627         return;
 628
 629     LogPrint(BCLog::MEMPOOL, "Checking mempool with %u transactions and %u inputs\n", (unsigned int)mapTx.size(), (unsigned int)mapNextTx.size());
 630
 631     uint64_t checkTotal = 0;
 632     uint64_t innerUsage = 0;
 633
 634     CCoinsViewCache mempoolDuplicate(const_cast<CCoinsViewCache*>(pcoins));
 635     const int64_t nSpendHeight = GetSpendHeight(mempoolDuplicate);
 636
 637     LOCK(cs);
 638     std::list<const CTxMemPoolEntry*> waitingOnDependants;
 639     for (indexed_transaction_set::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
 640         unsigned int i = 0;
 641         checkTotal += it->GetTxSize();
 642         innerUsage += it->DynamicMemoryUsage();
 643         const CTransaction& tx = it->GetTx();
 644         txlinksMap::const_iterator linksiter = mapLinks.find(it);
 645         assert(linksiter != mapLinks.end());
 646         const TxLinks &links = linksiter->second;
 647         innerUsage += memusage::DynamicUsage(links.parents) + memusage::DynamicUsage(links.children);
 648         bool fDependsWait = false;
 649         setEntries setParentCheck;
 650         int64_t parentSizes = 0;
 651         int64_t parentSigOpCost = 0;
 652         BOOST_FOREACH(const CTxIn &txin, tx.vin) {
 653             // Check that every mempool transaction's inputs refer to available coins, or other mempool tx's.
 654             indexed_transaction_set::const_iterator it2 = mapTx.find(txin.prevout.hash);
 655             if (it2 != mapTx.end()) {
 656                 const CTransaction& tx2 = it2->GetTx();
 657                 assert(tx2.vout.size() > txin.prevout.n && !tx2.vout[txin.prevout.n].IsNull());
 658                 fDependsWait = true;
 659                 if (setParentCheck.insert(it2).second) {
 660                     parentSizes += it2->GetTxSize();
 661                     parentSigOpCost += it2->GetSigOpCost();
 662                 }
 663             } else {
 664                 const CCoins* coins = pcoins->AccessCoins(txin.prevout.hash);
 665                 assert(coins && coins->IsAvailable(txin.prevout.n));
 666             }
 667             // Check whether its inputs are marked in mapNextTx.
 668             auto it3 = mapNextTx.find(txin.prevout);
 669             assert(it3 != mapNextTx.end());
 670             assert(it3->first == &txin.prevout);
 671             assert(it3->second == &tx);
 672             i++;
 673         }
 674         assert(setParentCheck == GetMemPoolParents(it));
 675         // Verify ancestor state is correct.
 676         setEntries setAncestors;
 677         uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
 678         std::string dummy;
 679         CalculateMemPoolAncestors(*it, setAncestors, nNoLimit, nNoLimit, nNoLimit, nNoLimit, dummy);
 680         uint64_t nCountCheck = setAncestors.size() + 1;
 681         uint64_t nSizeCheck = it->GetTxSize();
 682         CAmount nFeesCheck = it->GetModifiedFee();
 683         int64_t nSigOpCheck = it->GetSigOpCost();
 684
 685         BOOST_FOREACH(txiter ancestorIt, setAncestors) {
 686             nSizeCheck += ancestorIt->GetTxSize();
 687             nFeesCheck += ancestorIt->GetModifiedFee();
 688             nSigOpCheck += ancestorIt->GetSigOpCost();
 689         }
 690
 691         assert(it->GetCountWithAncestors() == nCountCheck);
 692         assert(it->GetSizeWithAncestors() == nSizeCheck);
 693         assert(it->GetSigOpCostWithAncestors() == nSigOpCheck);
 694         assert(it->GetModFeesWithAncestors() == nFeesCheck);
 695
 696         // Check children against mapNextTx
 697         CTxMemPool::setEntries setChildrenCheck;
 698         auto iter = mapNextTx.lower_bound(COutPoint(it->GetTx().GetHash(), 0));
 699         int64_t childSizes = 0;
 700         for (; iter != mapNextTx.end() && iter->first->hash == it->GetTx().GetHash(); ++iter) {
 701             txiter childit = mapTx.find(iter->second->GetHash());
 702             assert(childit != mapTx.end()); // mapNextTx points to in-mempool transactions
 703             if (setChildrenCheck.insert(childit).second) {
 704                 childSizes += childit->GetTxSize();
 705             }
 706         }
 707         assert(setChildrenCheck == GetMemPoolChildren(it));
 708         // Also check to make sure size is greater than sum with immediate children.
 709         // just a sanity check, not definitive that this calc is correct...
 710         assert(it->GetSizeWithDescendants() >= childSizes + it->GetTxSize());
 711
 712         if (fDependsWait)
 713             waitingOnDependants.push_back(&(*it));
 714         else {
 715             CValidationState state;
 716             bool fCheckResult = tx.IsCoinBase() ||
 717                 Consensus::CheckTxInputs(tx, state, mempoolDuplicate, nSpendHeight);
 718             assert(fCheckResult);
 719             UpdateCoins(tx, mempoolDuplicate, 1000000);
 720         }
 721     }
 722     unsigned int stepsSinceLastRemove = 0;
 723     while (!waitingOnDependants.empty()) {
 724         const CTxMemPoolEntry* entry = waitingOnDependants.front();
 725         waitingOnDependants.pop_front();
 726         CValidationState state;
 727         if (!mempoolDuplicate.HaveInputs(entry->GetTx())) {
 728             waitingOnDependants.push_back(entry);
 729             stepsSinceLastRemove++;
 730             assert(stepsSinceLastRemove < waitingOnDependants.size());
 731         } else {
 732             bool fCheckResult = entry->GetTx().IsCoinBase() ||
 733                 Consensus::CheckTxInputs(entry->GetTx(), state, mempoolDuplicate, nSpendHeight);
 734             assert(fCheckResult);
 735             UpdateCoins(entry->GetTx(), mempoolDuplicate, 1000000);
 736             stepsSinceLastRemove = 0;
 737         }
 738     }
 739     for (auto it = mapNextTx.cbegin(); it != mapNextTx.cend(); it++) {
 740         uint256 hash = it->second->GetHash();
 741         indexed_transaction_set::const_iterator it2 = mapTx.find(hash);
 742         const CTransaction& tx = it2->GetTx();
 743         assert(it2 != mapTx.end());
 744         assert(&tx == it->second);
 745     }
 746
 747     assert(totalTxSize == checkTotal);
 748     assert(innerUsage == cachedInnerUsage);
 749 }
 750
 751 bool CTxMemPool::CompareDepthAndScore(const uint256& hasha, const uint256& hashb)
 752 {
 753     LOCK(cs);
 754     indexed_transaction_set::const_iterator i = mapTx.find(hasha);
 755     if (i == mapTx.end()) return false;
 756     indexed_transaction_set::const_iterator j = mapTx.find(hashb);
 757     if (j == mapTx.end()) return true;
 758     uint64_t counta = i->GetCountWithAncestors();
 759     uint64_t countb = j->GetCountWithAncestors();
 760     if (counta == countb) {
 761         return CompareTxMemPoolEntryByScore()(*i, *j);
 762     }
 763     return counta < countb;
 764 }
 765
 766 namespace {
 767 class DepthAndScoreComparator
 768 {
 769 public:
 770     bool operator()(const CTxMemPool::indexed_transaction_set::const_iterator& a, const CTxMemPool::indexed_transaction_set::const_iterator& b)
 771     {
 772         uint64_t counta = a->GetCountWithAncestors();
 773         uint64_t countb = b->GetCountWithAncestors();
 774         if (counta == countb) {
 775             return CompareTxMemPoolEntryByScore()(*a, *b);
 776         }
 777         return counta < countb;
 778     }
 779 };
 780 }
 781
 782 std::vector<CTxMemPool::indexed_transaction_set::const_iterator> CTxMemPool::GetSortedDepthAndScore() const
 783 {
 784     std::vector<indexed_transaction_set::const_iterator> iters;
 785     AssertLockHeld(cs);
 786
 787     iters.reserve(mapTx.size());
 788
 789     for (indexed_transaction_set::iterator mi = mapTx.begin(); mi != mapTx.end(); ++mi) {
 790         iters.push_back(mi);
 791     }
 792     std::sort(iters.begin(), iters.end(), DepthAndScoreComparator());
 793     return iters;
 794 }
 795
 796 void CTxMemPool::queryHashes(std::vector<uint256>& vtxid)
 797 {
 798     LOCK(cs);
 799     auto iters = GetSortedDepthAndScore();
 800
 801     vtxid.clear();
 802     vtxid.reserve(mapTx.size());
 803
 804     for (auto it : iters) {
 805         vtxid.push_back(it->GetTx().GetHash());
 806     }
 807 }
 808
 809 static TxMempoolInfo GetInfo(CTxMemPool::indexed_transaction_set::const_iterator it) {
 810     return TxMempoolInfo{it->GetSharedTx(), it->GetTime(), CFeeRate(it->GetFee(), it->GetTxSize()), it->GetModifiedFee() - it->GetFee()};
 811 }
 812
 813 std::vector<TxMempoolInfo> CTxMemPool::infoAll() const
 814 {
 815     LOCK(cs);
 816     auto iters = GetSortedDepthAndScore();
 817
 818     std::vector<TxMempoolInfo> ret;
 819     ret.reserve(mapTx.size());
 820     for (auto it : iters) {
 821         ret.push_back(GetInfo(it));
 822     }
 823
 824     return ret;
 825 }
 826
 827 CTransactionRef CTxMemPool::get(const uint256& hash) const
 828 {
 829     LOCK(cs);
 830     indexed_transaction_set::const_iterator i = mapTx.find(hash);
 831     if (i == mapTx.end())
 832         return nullptr;
 833     return i->GetSharedTx();
 834 }
 835
 836 TxMempoolInfo CTxMemPool::info(const uint256& hash) const
 837 {
 838     LOCK(cs);
 839     indexed_transaction_set::const_iterator i = mapTx.find(hash);
 840     if (i == mapTx.end())
 841         return TxMempoolInfo();
 842     return GetInfo(i);
 843 }
 844
 845 void CTxMemPool::PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta)
 846 {
 847     {
 848         LOCK(cs);
 849         CAmount &delta = mapDeltas[hash];
 850         delta += nFeeDelta;
 851         txiter it = mapTx.find(hash);
 852         if (it != mapTx.end()) {
 853             mapTx.modify(it, update_fee_delta(delta));
 854             // Now update all ancestors' modified fees with descendants
 855             setEntries setAncestors;
 856             uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
 857             std::string dummy;
 858             CalculateMemPoolAncestors(*it, setAncestors, nNoLimit, nNoLimit, nNoLimit, nNoLimit, dummy, false);
 859             BOOST_FOREACH(txiter ancestorIt, setAncestors) {
 860                 mapTx.modify(ancestorIt, update_descendant_state(0, nFeeDelta, 0));
 861             }
 862             // Now update all descendants' modified fees with ancestors
 863             setEntries setDescendants;
 864             CalculateDescendants(it, setDescendants);
 865             setDescendants.erase(it);
 866             BOOST_FOREACH(txiter descendantIt, setDescendants) {
 867                 mapTx.modify(descendantIt, update_ancestor_state(0, nFeeDelta, 0, 0));
 868             }
 869             ++nTransactionsUpdated;
 870         }
 871     }
 872     LogPrintf("PrioritiseTransaction: %s feerate += %s\n", hash.ToString(), FormatMoney(nFeeDelta));
 873 }
 874
 875 void CTxMemPool::ApplyDelta(const uint256 hash, CAmount &nFeeDelta) const
 876 {
 877     LOCK(cs);
 878     std::map<uint256, CAmount>::const_iterator pos = mapDeltas.find(hash);
 879     if (pos == mapDeltas.end())
 880         return;
 881     const CAmount &delta = pos->second;
 882     nFeeDelta += delta;
 883 }
 884
 885 void CTxMemPool::ClearPrioritisation(const uint256 hash)
 886 {
 887     LOCK(cs);
 888     mapDeltas.erase(hash);
 889 }
 890
 891 bool CTxMemPool::HasNoInputsOf(const CTransaction &tx) const
 892 {
 893     for (unsigned int i = 0; i < tx.vin.size(); i++)
 894         if (exists(tx.vin[i].prevout.hash))
 895             return false;
 896     return true;
 897 }
 898
 899 CCoinsViewMemPool::CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn) : CCoinsViewBacked(baseIn), mempool(mempoolIn) { }
 900
 901 bool CCoinsViewMemPool::GetCoins(const uint256 &txid, CCoins &coins) const {
 902     // If an entry in the mempool exists, always return that one, as it's guaranteed to never
 903     // conflict with the underlying cache, and it cannot have pruned entries (as it contains full)
 904     // transactions. First checking the underlying cache risks returning a pruned entry instead.
 905     CTransactionRef ptx = mempool.get(txid);
 906     if (ptx) {
 907         coins = CCoins(*ptx, MEMPOOL_HEIGHT);
 908         return true;
 909     }
 910     return (base->GetCoins(txid, coins) && !coins.IsPruned());
 911 }
 912
 913 bool CCoinsViewMemPool::HaveCoins(const uint256 &txid) const {
 914     return mempool.exists(txid) || base->HaveCoins(txid);
 915 }
 916
 917 size_t CTxMemPool::DynamicMemoryUsage() const {
 918     LOCK(cs);
 919     // Estimate the overhead of mapTx to be 15 pointers + an allocation, as no exact formula for boost::multi_index_contained is implemented.
 920     return memusage::MallocUsage(sizeof(CTxMemPoolEntry) + 15 * sizeof(void*)) * mapTx.size() + memusage::DynamicUsage(mapNextTx) + memusage::DynamicUsage(mapDeltas) + memusage::DynamicUsage(mapLinks) + memusage::DynamicUsage(vTxHashes) + cachedInnerUsage;
 921 }
 922
 923 void CTxMemPool::RemoveStaged(setEntries &stage, bool updateDescendants, MemPoolRemovalReason reason) {
 924     AssertLockHeld(cs);
 925     UpdateForRemoveFromMempool(stage, updateDescendants);
 926     BOOST_FOREACH(const txiter& it, stage) {
 927         removeUnchecked(it, reason);
 928     }
 929 }
 930
 931 int CTxMemPool::Expire(int64_t time) {
 932     LOCK(cs);
 933     indexed_transaction_set::index<entry_time>::type::iterator it = mapTx.get<entry_time>().begin();
 934     setEntries toremove;
 935     while (it != mapTx.get<entry_time>().end() && it->GetTime() < time) {
 936         toremove.insert(mapTx.project<0>(it));
 937         it++;
 938     }
 939     setEntries stage;
 940     BOOST_FOREACH(txiter removeit, toremove) {
 941         CalculateDescendants(removeit, stage);
 942     }
 943     RemoveStaged(stage, false, MemPoolRemovalReason::EXPIRY);
 944     return stage.size();
 945 }
 946
 947 bool CTxMemPool::addUnchecked(const uint256&hash, const CTxMemPoolEntry &entry, bool validFeeEstimate)
 948 {
 949     LOCK(cs);
 950     setEntries setAncestors;
 951     uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
 952     std::string dummy;
 953     CalculateMemPoolAncestors(entry, setAncestors, nNoLimit, nNoLimit, nNoLimit, nNoLimit, dummy);
 954     return addUnchecked(hash, entry, setAncestors, validFeeEstimate);
 955 }
 956
 957 void CTxMemPool::UpdateChild(txiter entry, txiter child, bool add)
 958 {
 959     setEntries s;
 960     if (add && mapLinks[entry].children.insert(child).second) {
 961         cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
 962     } else if (!add && mapLinks[entry].children.erase(child)) {
 963         cachedInnerUsage -= memusage::IncrementalDynamicUsage(s);
 964     }
 965 }
 966
 967 void CTxMemPool::UpdateParent(txiter entry, txiter parent, bool add)
 968 {
 969     setEntries s;
 970     if (add && mapLinks[entry].parents.insert(parent).second) {
 971         cachedInnerUsage += memusage::IncrementalDynamicUsage(s);
 972     } else if (!add && mapLinks[entry].parents.erase(parent)) {
 973         cachedInnerUsage -= memusage::IncrementalDynamicUsage(s);
 974     }
 975 }
 976
 977 const CTxMemPool::setEntries & CTxMemPool::GetMemPoolParents(txiter entry) const
 978 {
 979     assert (entry != mapTx.end());
 980     txlinksMap::const_iterator it = mapLinks.find(entry);
 981     assert(it != mapLinks.end());
 982     return it->second.parents;
 983 }
 984
 985 const CTxMemPool::setEntries & CTxMemPool::GetMemPoolChildren(txiter entry) const
 986 {
 987     assert (entry != mapTx.end());
 988     txlinksMap::const_iterator it = mapLinks.find(entry);
 989     assert(it != mapLinks.end());
 990     return it->second.children;
 991 }
 992
 993 CFeeRate CTxMemPool::GetMinFee(size_t sizelimit) const {
 994     LOCK(cs);
 995     if (!blockSinceLastRollingFeeBump || rollingMinimumFeeRate == 0)
 996         return CFeeRate(rollingMinimumFeeRate);
 997
 998     int64_t time = GetTime();
 999     if (time > lastRollingFeeUpdate + 10) {
1000         double halflife = ROLLING_FEE_HALFLIFE;
1001         if (DynamicMemoryUsage() < sizelimit / 4)
1002             halflife /= 4;
1003         else if (DynamicMemoryUsage() < sizelimit / 2)
1004             halflife /= 2;
1005
1006         rollingMinimumFeeRate = rollingMinimumFeeRate / pow(2.0, (time - lastRollingFeeUpdate) / halflife);
1007         lastRollingFeeUpdate = time;
1008
1009         if (rollingMinimumFeeRate < (double)incrementalRelayFee.GetFeePerK() / 2) {
1010             rollingMinimumFeeRate = 0;
1011             return CFeeRate(0);
1012         }
1013     }
1014     return std::max(CFeeRate(rollingMinimumFeeRate), incrementalRelayFee);
1015 }
1016
1017 void CTxMemPool::trackPackageRemoved(const CFeeRate& rate) {
1018     AssertLockHeld(cs);
1019     if (rate.GetFeePerK() > rollingMinimumFeeRate) {
1020         rollingMinimumFeeRate = rate.GetFeePerK();
1021         blockSinceLastRollingFeeBump = false;
1022     }
1023 }
1024
1025 void CTxMemPool::TrimToSize(size_t sizelimit, std::vector<uint256>* pvNoSpendsRemaining) {
1026     LOCK(cs);
1027
1028     unsigned nTxnRemoved = 0;
1029     CFeeRate maxFeeRateRemoved(0);
1030     while (!mapTx.empty() && DynamicMemoryUsage() > sizelimit) {
1031         indexed_transaction_set::index<descendant_score>::type::iterator it = mapTx.get<descendant_score>().begin();
1032
1033         // We set the new mempool min fee to the feerate of the removed set, plus the
1034         // "minimum reasonable fee rate" (ie some value under which we consider txn
1035         // to have 0 fee). This way, we don't allow txn to enter mempool with feerate
1036         // equal to txn which were removed with no block in between.
1037         CFeeRate removed(it->GetModFeesWithDescendants(), it->GetSizeWithDescendants());
1038         removed += incrementalRelayFee;
1039         trackPackageRemoved(removed);
1040         maxFeeRateRemoved = std::max(maxFeeRateRemoved, removed);
1041
1042         setEntries stage;
1043         CalculateDescendants(mapTx.project<0>(it), stage);
1044         nTxnRemoved += stage.size();
1045
1046         std::vector<CTransaction> txn;
1047         if (pvNoSpendsRemaining) {
1048             txn.reserve(stage.size());
1049             BOOST_FOREACH(txiter iter, stage)
1050                 txn.push_back(iter->GetTx());
1051         }
1052         RemoveStaged(stage, false, MemPoolRemovalReason::SIZELIMIT);
1053         if (pvNoSpendsRemaining) {
1054             BOOST_FOREACH(const CTransaction& tx, txn) {
1055                 BOOST_FOREACH(const CTxIn& txin, tx.vin) {
1056                     if (exists(txin.prevout.hash))
1057                         continue;
1058                     auto iter = mapNextTx.lower_bound(COutPoint(txin.prevout.hash, 0));
1059                     if (iter == mapNextTx.end() || iter->first->hash != txin.prevout.hash)
1060                         pvNoSpendsRemaining->push_back(txin.prevout.hash);
1061                 }
1062             }
1063         }
1064     }
1065
1066     if (maxFeeRateRemoved > CFeeRate(0)) {
1067         LogPrint(BCLog::MEMPOOL, "Removed %u txn, rolling minimum fee bumped to %s\n", nTxnRemoved, maxFeeRateRemoved.ToString());
1068     }
1069 }
1070
1071 bool CTxMemPool::TransactionWithinChainLimit(const uint256& txid, size_t chainLimit) const {
1072     LOCK(cs);
1073     auto it = mapTx.find(txid);
1074     return it == mapTx.end() || (it->GetCountWithAncestors() < chainLimit &&
1075        it->GetCountWithDescendants() < chainLimit);
1076 }