mempool: Add explicit max_descendants

TransactionWithinChainLimits would take a 'limit' and check it against ascendants and descendants. This is changed to take an explicit
max ancestors and max descendants value, and to test the corresponding value against its corresponding max.

Author: kallewoof

src/txmempool.cpp

@@ -1055,11 +1055,11 @@ void CTxMemPool::TrimToSize(size_t sizelimit, std::vector<COutPoint>* pvNoSpends
     }
 }
 
-bool CTxMemPool::TransactionWithinChainLimit(const uint256& txid, size_t chainLimit) const {
+bool CTxMemPool::TransactionWithinChainLimit(const uint256& txid, size_t ancestor_limit, size_t descendant_limit) const {
     LOCK(cs);
     auto it = mapTx.find(txid);
-    return it == mapTx.end() || (it->GetCountWithAncestors() < chainLimit &&
-       it->GetCountWithDescendants() < chainLimit);
+    return it == mapTx.end() || (it->GetCountWithAncestors() < ancestor_limit &&
+       it->GetCountWithDescendants() < descendant_limit);
 }
 
 SaltedTxidHasher::SaltedTxidHasher() : k0(GetRand(std::numeric_limits<uint64_t>::max())), k1(GetRand(std::numeric_limits<uint64_t>::max())) {}

src/txmempool.h

@@ -620,7 +620,7 @@ class CTxMemPool
     int Expire(int64_t time);
 
     /** Returns false if the transaction is in the mempool and not within the chain limit specified. */
-    bool TransactionWithinChainLimit(const uint256& txid, size_t chainLimit) const;
+    bool TransactionWithinChainLimit(const uint256& txid, size_t ancestor_limit, size_t descendant_limit) const;
 
     unsigned long size()
     {

src/wallet/wallet.cpp

@@ -2469,7 +2469,7 @@ bool CWallet::OutputEligibleForSpending(const COutput& output, const CoinEligibi
     if (output.nDepth < (output.tx->IsFromMe(ISMINE_ALL) ? eligibility_filter.conf_mine : eligibility_filter.conf_theirs))
         return false;
 
-    if (!mempool.TransactionWithinChainLimit(output.tx->GetHash(), eligibility_filter.max_ancestors))
+    if (!mempool.TransactionWithinChainLimit(output.tx->GetHash(), eligibility_filter.max_ancestors, eligibility_filter.max_descendants))
         return false;
 
     return true;

src/wallet/wallet.h

@@ -662,8 +662,10 @@ struct CoinEligibilityFilter
     const int conf_mine;
     const int conf_theirs;
     const uint64_t max_ancestors;
+    const uint64_t max_descendants;
 
-    CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors) {}
+    CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors), max_descendants(max_ancestors) {}
+    CoinEligibilityFilter(int conf_mine, int conf_theirs, uint64_t max_ancestors, uint64_t max_descendants) : conf_mine(conf_mine), conf_theirs(conf_theirs), max_ancestors(max_ancestors), max_descendants(max_descendants) {}
 };
 
 class WalletRescanReserver; //forward declarations for ScanForWalletTransactions/RescanFromTime