Automatically add any matching outputs to a filter during matching.

src/bloom.cpp

@@ -88,16 +88,21 @@ bool CBloomFilter::IsWithinSizeConstraints() const
     return vData.size() <= MAX_BLOOM_FILTER_SIZE && nHashFuncs <= MAX_HASH_FUNCS;
 }
 
-bool CBloomFilter::IsTransactionRelevantToFilter(const CTransaction& tx, const uint256& hash) const
+bool CBloomFilter::IsRelevantAndUpdate(const CTransaction& tx, const uint256& hash)
 {
+    bool fFound = false;
     // Match if the filter contains the hash of tx
     //  for finding tx when they appear in a block
     if (contains(hash))
-        return true;
+        fFound = true;
 
-    BOOST_FOREACH(const CTxOut& txout, tx.vout)
+    for (unsigned int i = 0; i < tx.vout.size(); i++)
     {
+        const CTxOut& txout = tx.vout[i];
         // Match if the filter contains any arbitrary script data element in any scriptPubKey in tx
+        // If this matches, also add the specific output that was matched.
+        // This means clients don't have to update the filter themselves when a new relevant tx 
+        // is discovered in order to find spending transactions, which avoids round-tripping and race conditions.
         CScript::const_iterator pc = txout.scriptPubKey.begin();
         vector<unsigned char> data;
         while (pc < txout.scriptPubKey.end())
@@ -106,9 +111,16 @@ bool CBloomFilter::IsTransactionRelevantToFilter(const CTransaction& tx, const u
             if (!txout.scriptPubKey.GetOp(pc, opcode, data))
                 break;
             if (data.size() != 0 && contains(data))
+            {
+                fFound = true;
+                insert(COutPoint(hash, i));
+                break;
+            }
+        }
+    }
+
+    if (fFound)
         return true;
-        }
-    }
 
     BOOST_FOREACH(const CTxIn& txin, tx.vin)
     {

src/bloom.h

@@ -64,7 +64,8 @@ public:
     // (catch a filter which was just deserialized which was too big)
     bool IsWithinSizeConstraints() const;
 
-    bool IsTransactionRelevantToFilter(const CTransaction& tx, const uint256& hash) const;
+    // Also adds any outputs which match the filter to the filter (to match their spending txes)
+    bool IsRelevantAndUpdate(const CTransaction& tx, const uint256& hash);
 };
 
 #endif /* BITCOIN_BLOOM_H */

src/net.cpp

@@ -2034,7 +2034,7 @@ void RelayTransaction(const CTransaction& tx, const uint256& hash, const CDataSt
         LOCK(pnode->cs_filter);
         if (pnode->pfilter)
         {
-            if (pnode->pfilter->IsTransactionRelevantToFilter(tx, hash))
+            if (pnode->pfilter->IsRelevantAndUpdate(tx, hash))
                 pnode->PushInventory(inv);
         } else
             pnode->PushInventory(inv);