From 1b0bcc5f9573406bff1c3ffaf73826b0142d23cc Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Fri, 10 Jun 2016 16:07:14 +0200
Subject: [PATCH] Track orphan by prev COutPoint rather than prev hash

---
 src/main.cpp | 58 ++++++++++++++++++++++++++++++++--------------------
 1 file changed, 36 insertions(+), 22 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 6d006e878..17867c869 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -88,12 +88,21 @@ CAmount maxTxFee = DEFAULT_TRANSACTION_MAXFEE;
 CTxMemPool mempool(::minRelayTxFee);
 FeeFilterRounder filterRounder(::minRelayTxFee);
 
+struct IteratorComparator
+{
+    template<typename I>
+    bool operator()(const I& a, const I& b)
+    {
+        return &(*a) < &(*b);
+    }
+};
+
 struct COrphanTx {
     CTransaction tx;
     NodeId fromPeer;
 };
 map<uint256, COrphanTx> mapOrphanTransactions GUARDED_BY(cs_main);
-map<uint256, set<uint256> > mapOrphanTransactionsByPrev GUARDED_BY(cs_main);
+map<COutPoint, set<map<uint256, COrphanTx>::iterator, IteratorComparator>> mapOrphanTransactionsByPrev GUARDED_BY(cs_main);
 void EraseOrphansFor(NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
 
 /**
@@ -632,31 +641,33 @@ bool AddOrphanTx(const CTransaction& tx, NodeId peer) EXCLUSIVE_LOCKS_REQUIRED(c
         return false;
     }
 
-    mapOrphanTransactions[hash].tx = tx;
-    mapOrphanTransactions[hash].fromPeer = peer;
-    BOOST_FOREACH(const CTxIn& txin, tx.vin)
-        mapOrphanTransactionsByPrev[txin.prevout.hash].insert(hash);
+    auto ret = mapOrphanTransactions.emplace(hash, COrphanTx{tx, peer});
+    assert(ret.second);
+    BOOST_FOREACH(const CTxIn& txin, tx.vin) {
+        mapOrphanTransactionsByPrev[txin.prevout].insert(ret.first);
+    }
 
-    LogPrint("mempool", "stored orphan tx %s (mapsz %u prevsz %u)\n", hash.ToString(),
+    LogPrint("mempool", "stored orphan tx %s (mapsz %u outsz %u)\n", hash.ToString(),
              mapOrphanTransactions.size(), mapOrphanTransactionsByPrev.size());
     return true;
 }
 
-void static EraseOrphanTx(uint256 hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
+int static EraseOrphanTx(uint256 hash) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
     map<uint256, COrphanTx>::iterator it = mapOrphanTransactions.find(hash);
     if (it == mapOrphanTransactions.end())
-        return;
+        return 0;
     BOOST_FOREACH(const CTxIn& txin, it->second.tx.vin)
     {
-        map<uint256, set<uint256> >::iterator itPrev = mapOrphanTransactionsByPrev.find(txin.prevout.hash);
+        auto itPrev = mapOrphanTransactionsByPrev.find(txin.prevout);
         if (itPrev == mapOrphanTransactionsByPrev.end())
             continue;
-        itPrev->second.erase(hash);
+        itPrev->second.erase(it);
         if (itPrev->second.empty())
             mapOrphanTransactionsByPrev.erase(itPrev);
     }
     mapOrphanTransactions.erase(it);
+    return 1;
 }
 
 void EraseOrphansFor(NodeId peer)
@@ -668,8 +679,7 @@ void EraseOrphansFor(NodeId peer)
         map<uint256, COrphanTx>::iterator maybeErase = iter++; // increment to avoid iterator becoming invalid
         if (maybeErase->second.fromPeer == peer)
         {
-            EraseOrphanTx(maybeErase->second.tx.GetHash());
-            ++nErased;
+            nErased += EraseOrphanTx(maybeErase->second.tx.GetHash());
         }
     }
     if (nErased > 0) LogPrint("mempool", "Erased %d orphan tx from peer %d\n", nErased, peer);
@@ -5019,7 +5029,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
             return true;
         }
 
-        vector<uint256> vWorkQueue;
+        deque<COutPoint> vWorkQueue;
         vector<uint256> vEraseQueue;
         CTransaction tx;
         vRecv >> tx;
@@ -5038,7 +5048,9 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
         if (!AlreadyHave(inv) && AcceptToMemoryPool(mempool, state, tx, true, &fMissingInputs)) {
             mempool.check(pcoinsTip);
             RelayTransaction(tx);
-            vWorkQueue.push_back(inv.hash);
+            for (unsigned int i = 0; i < tx.vout.size(); i++) {
+                vWorkQueue.emplace_back(inv.hash, i);
+            }
 
             LogPrint("mempool", "AcceptToMemoryPool: peer=%d: accepted %s (poolsz %u txn, %u kB)\n",
                 pfrom->id,
@@ -5047,18 +5059,18 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
 
             // Recursively process any orphan transactions that depended on this one
             set<NodeId> setMisbehaving;
-            for (unsigned int i = 0; i < vWorkQueue.size(); i++)
-            {
-                map<uint256, set<uint256> >::iterator itByPrev = mapOrphanTransactionsByPrev.find(vWorkQueue[i]);
+            while (!vWorkQueue.empty()) {
+                auto itByPrev = mapOrphanTransactionsByPrev.find(vWorkQueue.front());
+                vWorkQueue.pop_front();
                 if (itByPrev == mapOrphanTransactionsByPrev.end())
                     continue;
-                for (set<uint256>::iterator mi = itByPrev->second.begin();
+                for (auto mi = itByPrev->second.begin();
                      mi != itByPrev->second.end();
                      ++mi)
                 {
-                    const uint256& orphanHash = *mi;
-                    const CTransaction& orphanTx = mapOrphanTransactions[orphanHash].tx;
-                    NodeId fromPeer = mapOrphanTransactions[orphanHash].fromPeer;
+                    const CTransaction& orphanTx = (*mi)->second.tx;
+                    const uint256& orphanHash = orphanTx.GetHash();
+                    NodeId fromPeer = (*mi)->second.fromPeer;
                     bool fMissingInputs2 = false;
                     // Use a dummy CValidationState so someone can't setup nodes to counter-DoS based on orphan
                     // resolution (that is, feeding people an invalid transaction based on LegitTxX in order to get
@@ -5071,7 +5083,9 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     if (AcceptToMemoryPool(mempool, stateDummy, orphanTx, true, &fMissingInputs2)) {
                         LogPrint("mempool", "   accepted orphan tx %s\n", orphanHash.ToString());
                         RelayTransaction(orphanTx);
-                        vWorkQueue.push_back(orphanHash);
+                        for (unsigned int i = 0; i < orphanTx.vout.size(); i++) {
+                            vWorkQueue.emplace_back(orphanHash, i);
+                        }
                         vEraseQueue.push_back(orphanHash);
                     }
                     else if (!fMissingInputs2)