Merge #8498: Near-Bugfix: Optimization: Minimize the number of times it is checked that no money...

4e955c5 Near-Bugfix: Reestablish consensus check removed in 8d7849b (Jorge Timón)
3e8c916 Introduce CheckInputsAndUpdateCoins static wrapper in txmempool.cpp (Jorge Timón)
832e074 Optimization: Minimize the number of times it is checked that no money is created (Jorge Timón)
3f0ee3e Proper indentation for CheckTxInputs and other minor fixes (Jorge Timón)

Pull request description:

  ...is created by individual transactions to 2 places (but call only once in each):

  - ConnectBlock ( before calculated fees per txs twice )
  - AcceptToMemoryPoolWorker ( before called CheckTxInputs 4 times and calculated
     fees per tx one extra time )

  Also call tx.GetValueOut() only once per call of CheckTxInputs (instead of 2)

  For more motivation:

  ~~https://github.com/bitcoin/bitcoin/blob/master/src/main.cpp#L1493~~
  https://github.com/jtimon/bitcoin/compare/0.13-consensus-inputs...jtimon:0.13-consensus-inputs-comments

  EDIT: partially replaces #6445

  Near-Bugfix as pointed out in https://github.com/bitcoin/bitcoin/pull/8498#discussion_r124346132

Tree-SHA512: c71188e7c7c2425c9170ed7b803896755a92fd22f43b136eedaa6e554106696f0b10271d0ef0d0127c1eaafbc31d12eb19143df4f1b6882feecedf6ef05ea346

1 files changed, 15 insertions, 13 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index e098de5d3d..a073e3d1c0 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -534,7 +534,6 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
         CCoinsView dummy;
         CCoinsViewCache view(&dummy);
 
-        CAmount nValueIn = 0;
         LockPoints lp;
         {
         LOCK(pool.cs);
@@ -565,8 +564,6 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
         // Bring the best block into scope
         view.GetBestBlock();
 
-        nValueIn = view.GetValueIn(tx);
-
         // we have all inputs cached now, so switch back to dummy, so we don't need to keep lock on mempool
         view.SetBackend(dummy);
 
@@ -577,6 +574,12 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
         // CoinsViewCache instead of create its own
         if (!CheckSequenceLocks(tx, STANDARD_LOCKTIME_VERIFY_FLAGS, &lp))
             return state.DoS(0, false, REJECT_NONSTANDARD, "non-BIP68-final");
+
+        } // end LOCK(pool.cs)
+
+        CAmount nFees = 0;
+        if (!Consensus::CheckTxInputs(tx, state, view, GetSpendHeight(view), nFees)) {
+            return error("%s: Consensus::CheckTxInputs: %s, %s", __func__, tx.GetHash().ToString(), FormatStateMessage(state));
         }
 
         // Check for non-standard pay-to-script-hash in inputs
@@ -589,8 +592,6 @@ static bool AcceptToMemoryPoolWorker(const CChainParams& chainparams, CTxMemPool
 
         int64_t nSigOpsCost = GetTransactionSigOpCost(tx, view, STANDARD_SCRIPT_VERIFY_FLAGS);
 
-        CAmount nValueOut = tx.GetValueOut();
-        CAmount nFees = nValueIn-nValueOut;
         // nModifiedFees includes any fee deltas from PrioritiseTransaction
         CAmount nModifiedFees = nFees;
         pool.ApplyDelta(hash, nModifiedFees);
@@ -1247,9 +1248,6 @@ bool CheckInputs(const CTransaction& tx, CValidationState &state, const CCoinsVi
 {
     if (!tx.IsCoinBase())
     {
-        if (!Consensus::CheckTxInputs(tx, state, inputs, GetSpendHeight(inputs)))
-            return false;
-
         if (pvChecks)
             pvChecks->reserve(tx.vin.size());
 
@@ -1762,9 +1760,15 @@ static bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockInd
 
         if (!tx.IsCoinBase())
         {
-            if (!view.HaveInputs(tx))
-                return state.DoS(100, error("ConnectBlock(): inputs missing/spent"),
-                                 REJECT_INVALID, "bad-txns-inputs-missingorspent");
+            CAmount txfee = 0;
+            if (!Consensus::CheckTxInputs(tx, state, view, pindex->nHeight, txfee)) {
+                return error("%s: Consensus::CheckTxInputs: %s, %s", __func__, tx.GetHash().ToString(), FormatStateMessage(state));
+            }
+            nFees += txfee;
+            if (!MoneyRange(nFees)) {
+                return state.DoS(100, error("%s: accumulated fee in the block out of range.", __func__),
+                                 REJECT_INVALID, "bad-txns-accumulated-fee-outofrange");
+            }
 
             // Check that transaction is BIP68 final
             // BIP68 lock checks (as opposed to nLockTime checks) must
@@ -1792,8 +1796,6 @@ static bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockInd
         txdata.emplace_back(tx);
         if (!tx.IsCoinBase())
         {
-            nFees += view.GetValueIn(tx)-tx.GetValueOut();
-
             std::vector<CScriptCheck> vChecks;
             bool fCacheResults = fJustCheck; /* Don't cache results if we're actually connecting blocks (still consult the cache, though) */
             if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : nullptr))