[backport#10953] [Refactor] Combine scriptPubKey and amount as CTxOut…

… in CScriptCheck

Summary:
3a131b7 Rename out to m_tx_out in CScriptCheck (Johnson Lau)
e912118 [Refactor] Combine scriptPubKey and amount as CTxOut in CScriptCheck (Johnson Lau)

Pull request description:

  This simplifies CScriptCheck by combining scriptPubKey and amount

---

Backport of Core [[bitcoin/bitcoin#10953 | PR10953]]

Test Plan:
  ninja check && ninja check-functional

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D6932

src/test/script_p2sh_tests.cpp

@@ -115,12 +115,12 @@ BOOST_AUTO_TEST_CASE(sign) {
         for (int j = 0; j < 8; j++) {
             CScript sigSave = txTo[i].vin[0].scriptSig;
             txTo[i].vin[0].scriptSig = txTo[j].vin[0].scriptSig;
-            const CTxOut &output = txFrom.vout[txTo[i].vin[0].prevout.GetN()];
-            bool sigOK = CScriptCheck(
-                output.scriptPubKey, output.nValue, CTransaction(txTo[i]), 0,
-                SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC |
-                    SCRIPT_ENABLE_SIGHASH_FORKID,
-                false, txdata)();
+            bool sigOK =
+                CScriptCheck(txFrom.vout[txTo[i].vin[0].prevout.GetN()],
+                             CTransaction(txTo[i]), 0,
+                             SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC |
+                                 SCRIPT_ENABLE_SIGHASH_FORKID,
+                             false, txdata)();
             if (i == j) {
                 BOOST_CHECK_MESSAGE(sigOK,
                                     strprintf("VerifySignature %d %d", i, j));

src/test/transaction_tests.cpp

@@ -488,8 +488,7 @@ BOOST_AUTO_TEST_CASE(test_big_transaction) {
 
     for (size_t i = 0; i < mtx.vin.size(); i++) {
         std::vector<CScriptCheck> vChecks;
-        CTxOut &out = coins[tx.vin[i].prevout.GetN()].GetTxOut();
-        CScriptCheck check(out.scriptPubKey, out.nValue, tx, i,
+        CScriptCheck check(coins[tx.vin[i].prevout.GetN()].GetTxOut(), tx, i,
                            STANDARD_SCRIPT_VERIFY_FLAGS, false, txdata);
         vChecks.push_back(CScriptCheck());
         check.swap(vChecks.back());

src/validation.cpp

@@ -996,9 +996,9 @@ void UpdateCoins(CCoinsViewCache &view, const CTransaction &tx, int nHeight) {
 
 bool CScriptCheck::operator()() {
     const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
-    if (!VerifyScript(scriptSig, scriptPubKey, nFlags,
-                      CachingTransactionSignatureChecker(ptxTo, nIn, amount,
-                                                         cacheStore, txdata),
+    if (!VerifyScript(scriptSig, m_tx_out.scriptPubKey, nFlags,
+                      CachingTransactionSignatureChecker(
+                          ptxTo, nIn, m_tx_out.nValue, cacheStore, txdata),
                       metrics, &error)) {
         return false;
     }
@@ -1072,12 +1072,10 @@ bool CheckInputs(const CTransaction &tx, TxValidationState &state,
         // check that our caching is not introducing consensus failures through
         // additional data in, eg, the coins being spent being checked as a part
         // of CScriptCheck.
-        const CScript &scriptPubKey = coin.GetTxOut().scriptPubKey;
-        const Amount amount = coin.GetTxOut().nValue;
 
         // Verify signature
-        CScriptCheck check(scriptPubKey, amount, tx, i, flags, sigCacheStore,
-                           txdata, &txLimitSigChecks, pBlockLimitSigChecks);
+        CScriptCheck check(coin.GetTxOut(), tx, i, flags, sigCacheStore, txdata,
+                           &txLimitSigChecks, pBlockLimitSigChecks);
         if (pvChecks) {
             pvChecks->push_back(std::move(check));
         } else if (!check()) {
@@ -1094,7 +1092,7 @@ bool CheckInputs(const CTransaction &tx, TxValidationState &state,
                 // NOT_STANDARD instead of CONSENSUS to avoid downstream users
                 // splitting the network between upgraded and non-upgraded nodes
                 // by banning CONSENSUS-failing data providers.
-                CScriptCheck check2(scriptPubKey, amount, tx, i, mandatoryFlags,
+                CScriptCheck check2(coin.GetTxOut(), tx, i, mandatoryFlags,
                                     sigCacheStore, txdata);
                 if (check2()) {
                     return state.Invalid(

src/validation.h

@@ -581,8 +581,7 @@ bool CheckSequenceLocks(const CTxMemPool &pool, const CTransaction &tx,
  */
 class CScriptCheck {
 private:
-    CScript scriptPubKey;
-    Amount amount;
+    CTxOut m_tx_out;
     const CTransaction *ptxTo;
     unsigned int nIn;
     uint32_t nFlags;
@@ -595,28 +594,25 @@ class CScriptCheck {
 
 public:
     CScriptCheck()
-        : amount(), ptxTo(nullptr), nIn(0), nFlags(0), cacheStore(false),
+        : ptxTo(nullptr), nIn(0), nFlags(0), cacheStore(false),
           error(ScriptError::UNKNOWN), txdata(), pTxLimitSigChecks(nullptr),
           pBlockLimitSigChecks(nullptr) {}
 
-    CScriptCheck(const CScript &scriptPubKeyIn, const Amount amountIn,
-                 const CTransaction &txToIn, unsigned int nInIn,
-                 uint32_t nFlagsIn, bool cacheIn,
+    CScriptCheck(const CTxOut &outIn, const CTransaction &txToIn,
+                 unsigned int nInIn, uint32_t nFlagsIn, bool cacheIn,
                  const PrecomputedTransactionData &txdataIn,
                  TxSigCheckLimiter *pTxLimitSigChecksIn = nullptr,
                  CheckInputsLimiter *pBlockLimitSigChecksIn = nullptr)
-        : scriptPubKey(scriptPubKeyIn), amount(amountIn), ptxTo(&txToIn),
-          nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn),
-          error(ScriptError::UNKNOWN), txdata(txdataIn),
+        : m_tx_out(outIn), ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn),
+          cacheStore(cacheIn), error(ScriptError::UNKNOWN), txdata(txdataIn),
           pTxLimitSigChecks(pTxLimitSigChecksIn),
           pBlockLimitSigChecks(pBlockLimitSigChecksIn) {}
 
     bool operator()();
 
     void swap(CScriptCheck &check) {
-        scriptPubKey.swap(check.scriptPubKey);
         std::swap(ptxTo, check.ptxTo);
-        std::swap(amount, check.amount);
+        std::swap(m_tx_out, check.m_tx_out);
         std::swap(nIn, check.nIn);
         std::swap(nFlags, check.nFlags);
         std::swap(cacheStore, check.cacheStore);