Cache transaction validation successes

Conflicts:
	src/main.cpp
	src/test/test_bitcoin.cpp

Github-Pull: #6077
Rebased-From: 17b11428c135203342aff38cabc8047e673f38ac 517e6dd25618522c716e64859554b0f29c6e65d0

src/main.cpp

@@ -1397,10 +1397,24 @@ bool CScriptCheck::operator()() {
     return true;
 }
 
+static mrumap<uint256, unsigned int> cacheCheck(2 * MAX_BLOCK_SIZE / CTransaction().GetSerializeSize(SER_NETWORK, PROTOCOL_VERSION));
+static boost::mutex cs_cacheCheck;
+
 bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsViewCache &inputs, bool fScriptChecks, unsigned int flags, bool cacheStore, std::vector<CScriptCheck> *pvChecks)
 {
     if (!tx.IsCoinBase())
     {
+        if (fScriptChecks) {
+            boost::unique_lock<boost::mutex> lock(cs_cacheCheck);
+            mrumap<uint256, unsigned int>::const_iterator iter = cacheCheck.find(tx.GetHash());
+            if (iter != cacheCheck.end()) {
+                // The following test relies on the fact that all script validation flags are softforks (i.e. an extra bit set cannot cause a false result to become true).
+                if ((iter->second & flags) == flags) {
+                    return true;
+                }
+            }
+        }
+
         if (pvChecks)
             pvChecks->reserve(tx.vin.size());
 
@@ -1496,6 +1510,11 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
         }
     }
 
+    if (cacheStore && fScriptChecks && pvChecks == NULL) {
+        boost::unique_lock<boost::mutex> lock(cs_cacheCheck);
+        cacheCheck.insert(tx.GetHash(), flags);
+    }
+
     return true;
 }
 
@@ -2210,6 +2229,13 @@ bool static ConnectTip(CValidationState &state, CBlockIndex *pindexNew, CBlock *
     BOOST_FOREACH(const CTransaction &tx, pblock->vtx) {
         SyncWithWallets(tx, pblock);
     }
+    // Erase block's transactions from the validation cache
+    {
+        boost::unique_lock<boost::mutex> lock(cs_cacheCheck);
+        BOOST_FOREACH(const CTransaction &tx, pblock->vtx) {
+            cacheCheck.erase(tx.GetHash());
+        }
+    }
 
     int64_t nTime6 = GetTimeMicros(); nTimePostConnect += nTime6 - nTime5; nTimeTotal += nTime6 - nTime1;
     LogPrint("bench", "  - Connect postprocess: %.2fms [%.2fs]\n", (nTime6 - nTime5) * 0.001, nTimePostConnect * 0.000001);