Give high priority to zerocoinspends to make it into the next block.

Prevent zerocoinspends from remaining in the mempool for extended periods of time to prevent their serial numbers from floating in the mempool instead of being solidified into the blockchain and unable to be trolled.

src/main.cpp

@@ -97,6 +97,7 @@ struct COrphanTx {
 map<uint256, COrphanTx> mapOrphanTransactions;
 map<uint256, set<uint256> > mapOrphanTransactionsByPrev;
 map<uint256, int64_t> mapRejectedBlocks;
+map<uint256, int64_t> mapZerocoinspends; //txid, time received
 
 
 void EraseOrphansFor(NodeId peer);
@@ -1822,6 +1823,10 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState& state, const CTransa
 
     SyncWithWallets(tx, NULL);
 
+    //Track zerocoinspends and ensure that they are given priority to make it into the blockchain
+    if (tx.IsZerocoinSpend())
+        mapZerocoinspends[tx.GetHash()] = GetAdjustedTime();
+
     return true;
 }
 
@@ -3340,6 +3345,7 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
     CAmount nValueOut = 0;
     CAmount nValueIn = 0;
     unsigned int nMaxBlockSigOps = MAX_BLOCK_SIGOPS_CURRENT;
+    vector<uint256> vSpendsInBlock;
     for (unsigned int i = 0; i < block.vtx.size(); i++) {
         const CTransaction& tx = block.vtx[i];
 
@@ -3355,7 +3361,9 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
         }
         if (tx.IsZerocoinSpend()) {
             int nHeightTx = 0;
-            if (IsTransactionInChain(tx.GetHash(), nHeightTx)) {
+            uint256 txid = tx.GetHash();
+            vSpendsInBlock.emplace_back(txid);
+            if (IsTransactionInChain(txid, nHeightTx)) {
                 //when verifying blocks on init, the blocks are scanned without being disconnected - prevent that from causing an error
                 if (!fVerifyingBlocks || (fVerifyingBlocks && pindex->nHeight > nHeightTx))
                     return state.DoS(100, error("%s : txid %s already exists in block %d , trying to include it again in block %d", __func__,
@@ -3600,6 +3608,13 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
     if (pindex->nHeight >= Params().Zerocoin_Block_FirstFraudulent() && pindex->nHeight <= Params().Zerocoin_Block_RecalculateAccumulators() + 1)
         AddInvalidSpendsToMap(block);
 
+    //Remove zerocoinspends from the pending map
+    for (const uint256& txid : vSpendsInBlock) {
+        auto it = mapZerocoinspends.find(txid);
+        if (it != mapZerocoinspends.end())
+            mapZerocoinspends.erase(it);
+    }
+
     return true;
 }
 

src/main.h

@@ -159,6 +159,7 @@ extern std::map<unsigned int, unsigned int> mapHashedBlocks;
 extern std::map<COutPoint, COutPoint> mapInvalidOutPoints;
 extern std::map<CBigNum, CAmount> mapInvalidSerials;
 extern std::set<std::pair<COutPoint, unsigned int> > setStakeSeen;
+extern std::map<uint256, int64_t> mapZerocoinspends; //txid, time received
 
 /** Best header we've seen so far (used for getheaders queries' starting points). */
 extern CBlockIndex* pindexBestHeader;

src/miner.cpp

@@ -199,11 +199,42 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn, CWallet* pwallet,
             double dPriority = 0;
             CAmount nTotalIn = 0;
             bool fMissingInputs = false;
+            uint256 txid = tx.GetHash();
             for (const CTxIn& txin : tx.vin) {
                 //zerocoinspend has special vin
                 if (tx.IsZerocoinSpend()) {
                     nTotalIn = tx.GetZerocoinSpent();
-                    break;
+
+                    //Give a high priority to zerocoinspends to get into the next block
+                    //Priority = (age^6+100000)*amount - gives higher priority to zpivs that have been in mempool long
+                    //and higher priority to zpivs that are large in value
+                    int64_t nTimeSeen = GetAdjustedTime();
+                    double nConfs = 100000;
+                    double dPriorityPrev = dPriority;
+
+                    auto it = mapZerocoinspends.find(txid);
+                    if (it != mapZerocoinspends.end()) {
+                        nTimeSeen = it->second;
+                    } else {
+                        //for some reason not in map, add it
+                        mapZerocoinspends[txid] = nTimeSeen;
+                    }
+
+                    //zPIV spends can have very large priority, prevent datatype problems
+                    double nTimePriority = std::pow(GetAdjustedTime() - nTimeSeen, 6);
+                    double fLimit = std::numeric_limits<double>::max() - dPriority;
+                    if (fLimit > (nTimePriority * nConfs))
+                        dPriority += nTimePriority * nConfs;
+                    else
+                        dPriority = std::numeric_limits<double>::max();
+
+                    fLimit = std::numeric_limits<double>::max() / dPriority;
+                    if (fLimit > nTotalIn)
+                        dPriority *= nTotalIn;
+                    else
+                        dPriority = std::numeric_limits<double>::max();
+
+                    continue;
                 }
 
                 // Read prev transaction
@@ -247,7 +278,13 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn, CWallet* pwallet,
 
                 int nConf = nHeight - coins->nHeight;
 
-                dPriority += (double)nValueIn * nConf;
+                //zPIV spends can have very large priority, prevent datatype problems
+                double fLimit = std::numeric_limits<double>::max() - dPriority;
+
+                if (fLimit > ((double)nValueIn * nConf))
+                    dPriority += (double)nValueIn * nConf;
+                else
+                    dPriority = std::numeric_limits<double>::max();
             }
             if (fMissingInputs) continue;