1 files changed, 46 insertions, 23 deletions

diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 083022fbdd..23d5b72a5c 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -1,5 +1,5 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
-// Copyright (c) 2009-2019 The Bitcoin Core developers
+// Copyright (c) 2009-2020 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -342,6 +342,35 @@ public:
 };
 }
 
+/** Helper for OP_CHECKSIG and OP_CHECKSIGVERIFY
+ *
+ * A return value of false means the script fails entirely. When true is returned, the
+ * fSuccess variable indicates whether the signature check itself succeeded.
+ */
+static bool EvalChecksig(const valtype& vchSig, const valtype& vchPubKey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& fSuccess)
+{
+    // Subset of script starting at the most recent codeseparator
+    CScript scriptCode(pbegincodehash, pend);
+
+    // Drop the signature in pre-segwit scripts but not segwit scripts
+    if (sigversion == SigVersion::BASE) {
+        int found = FindAndDelete(scriptCode, CScript() << vchSig);
+        if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
+            return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE);
+    }
+
+    if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
+        //serror is set
+        return false;
+    }
+    fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion);
+
+    if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size())
+        return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);
+
+    return true;
+}
+
 bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)
 {
     static const CScriptNum bnZero(0);
@@ -985,25 +1014,8 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
                     valtype& vchSig    = stacktop(-2);
                     valtype& vchPubKey = stacktop(-1);
 
-                    // Subset of script starting at the most recent codeseparator
-                    CScript scriptCode(pbegincodehash, pend);
-
-                    // Drop the signature in pre-segwit scripts but not segwit scripts
-                    if (sigversion == SigVersion::BASE) {
-                        int found = FindAndDelete(scriptCode, CScript() << vchSig);
-                        if (found > 0 && (flags & SCRIPT_VERIFY_CONST_SCRIPTCODE))
-                            return set_error(serror, SCRIPT_ERR_SIG_FINDANDDELETE);
-                    }
-
-                    if (!CheckSignatureEncoding(vchSig, flags, serror) || !CheckPubKeyEncoding(vchPubKey, flags, sigversion, serror)) {
-                        //serror is set
-                        return false;
-                    }
-                    bool fSuccess = checker.CheckSig(vchSig, vchPubKey, scriptCode, sigversion);
-
-                    if (!fSuccess && (flags & SCRIPT_VERIFY_NULLFAIL) && vchSig.size())
-                        return set_error(serror, SCRIPT_ERR_SIG_NULLFAIL);
-
+                    bool fSuccess = true;
+                    if (!EvalChecksig(vchSig, vchPubKey, pbegincodehash, pend, flags, checker, sigversion, serror, fSuccess)) return false;
                     popstack(stack);
                     popstack(stack);
                     stack.push_back(fSuccess ? vchTrue : vchFalse);
@@ -1279,18 +1291,29 @@ uint256 GetOutputsHash(const T& txTo)
 } // namespace
 
 template <class T>
-PrecomputedTransactionData::PrecomputedTransactionData(const T& txTo)
+void PrecomputedTransactionData::Init(const T& txTo)
 {
+    assert(!m_ready);
+
     // Cache is calculated only for transactions with witness
     if (txTo.HasWitness()) {
         hashPrevouts = GetPrevoutHash(txTo);
         hashSequence = GetSequenceHash(txTo);
         hashOutputs = GetOutputsHash(txTo);
-        ready = true;
     }
+
+    m_ready = true;
+}
+
+template <class T>
+PrecomputedTransactionData::PrecomputedTransactionData(const T& txTo)
+{
+    Init(txTo);
 }
 
 // explicit instantiation
+template void PrecomputedTransactionData::Init(const CTransaction& txTo);
+template void PrecomputedTransactionData::Init(const CMutableTransaction& txTo);
 template PrecomputedTransactionData::PrecomputedTransactionData(const CTransaction& txTo);
 template PrecomputedTransactionData::PrecomputedTransactionData(const CMutableTransaction& txTo);
 
@@ -1303,7 +1326,7 @@ uint256 SignatureHash(const CScript& scriptCode, const T& txTo, unsigned int nIn
         uint256 hashPrevouts;
         uint256 hashSequence;
         uint256 hashOutputs;
-        const bool cacheready = cache && cache->ready;
+        const bool cacheready = cache && cache->m_ready;
 
         if (!(nHashType & SIGHASH_ANYONECANPAY)) {
             hashPrevouts = cacheready ? cache->hashPrevouts : GetPrevoutHash(txTo);