Merge #21166: Introduce DeferredSignatureChecker and have SignatureExtractorClass subclass it

a97a9298ce Test that signrawtx works when a signed CSV and CLTV inputs are present (Andrew Chow)
6965456c10 Introduce DeferringSignatureChecker and inherit with SignatureExtractor (Andrew Chow)

Pull request description:

  Previously SignatureExtractorChecker took a MutableTransactionSignatureChecker and passed through function calls to that. However not all functions were implemented so not everything passed through as it should have. To solve this, SignatureExctractorChecker now implements all of those functions via a new class - DeferredSignatureChecker. DeferredSignatureChecker is introduced to allow for future signature checkers which use another SignatureChecker but need to be able to do somethings outside of just the signature checking.

  Fixes #21151

ACKs for top commit:
  sipa:
    utACK a97a9298ce
  meshcollider:
    Code review ACK a97a9298ce
  instagibbs:
    utACK a97a9298ce

Tree-SHA512: bca784c75c2fc3fcb74e81f4e3ff516699e8debaa2db81e12843abdfe9cf265dac11db8619751cb9b3e9bbe779805d029fabe5f3cbca5e86bfd72de3664b0b94

src/script/interpreter.h

@@ -272,6 +272,34 @@ public:
 using TransactionSignatureChecker = GenericTransactionSignatureChecker<CTransaction>;
 using MutableTransactionSignatureChecker = GenericTransactionSignatureChecker<CMutableTransaction>;
 
+class DeferringSignatureChecker : public BaseSignatureChecker
+{
+protected:
+    BaseSignatureChecker& m_checker;
+
+public:
+    DeferringSignatureChecker(BaseSignatureChecker& checker) : m_checker(checker) {}
+
+    bool CheckECDSASignature(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const override
+    {
+        return m_checker.CheckECDSASignature(scriptSig, vchPubKey, scriptCode, sigversion);
+    }
+
+    bool CheckSchnorrSignature(Span<const unsigned char> sig, Span<const unsigned char> pubkey, SigVersion sigversion, const ScriptExecutionData& execdata, ScriptError* serror = nullptr) const override
+    {
+        return m_checker.CheckSchnorrSignature(sig, pubkey, sigversion, execdata, serror);
+    }
+
+    bool CheckLockTime(const CScriptNum& nLockTime) const override
+    {
+        return m_checker.CheckLockTime(nLockTime);
+    }
+    bool CheckSequence(const CScriptNum& nSequence) const override
+    {
+        return m_checker.CheckSequence(nSequence);
+    }
+};
+
 bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* error = nullptr);
 bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* error = nullptr);
 bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror = nullptr);

src/script/sign.cpp

@@ -250,17 +250,17 @@ bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreato
 }
 
 namespace {
-class SignatureExtractorChecker final : public BaseSignatureChecker
+class SignatureExtractorChecker final : public DeferringSignatureChecker
 {
 private:
     SignatureData& sigdata;
-    BaseSignatureChecker& checker;
 
 public:
-    SignatureExtractorChecker(SignatureData& sigdata, BaseSignatureChecker& checker) : sigdata(sigdata), checker(checker) {}
+    SignatureExtractorChecker(SignatureData& sigdata, BaseSignatureChecker& checker) : DeferringSignatureChecker(checker), sigdata(sigdata) {}
+
     bool CheckECDSASignature(const std::vector<unsigned char>& scriptSig, const std::vector<unsigned char>& vchPubKey, const CScript& scriptCode, SigVersion sigversion) const override
     {
-        if (checker.CheckECDSASignature(scriptSig, vchPubKey, scriptCode, sigversion)) {
+        if (m_checker.CheckECDSASignature(scriptSig, vchPubKey, scriptCode, sigversion)) {
             CPubKey pubkey(vchPubKey);
             sigdata.signatures.emplace(pubkey.GetID(), SigPair(pubkey, scriptSig));
             return true;