script/interpreter: introduce script_verify_flags typename

Previously the SCRIPT_VERIFY_* flags were specified as either uint32_t,
unsigned int, or unsigned. This converts them to a common type alias in
preparation for changing the underlying type.

Author: ajtowns

src/bench/verify_script.cpp

@@ -24,7 +24,7 @@ static void VerifyScriptBench(benchmark::Bench& bench)
 {
     ECC_Context ecc_context{};
 
-    const uint32_t flags{SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH};
+    const script_verify_flags flags{SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH};
     const int witnessversion = 0;
 
     // Key pair.

src/consensus/params.h

@@ -6,6 +6,7 @@
 #ifndef BITCOIN_CONSENSUS_PARAMS_H
 #define BITCOIN_CONSENSUS_PARAMS_H
 
+#include <script/verify_flags.h>
 #include <uint256.h>
 
 #include <array>
@@ -89,7 +90,7 @@ struct Params {
      * - buried in the chain, and
      * - fail if the default script verify flags are applied.
      */
-    std::map<uint256, uint32_t> script_flag_exceptions;
+    std::map<uint256, script_verify_flags> script_flag_exceptions;
     /** Block height and hash at which BIP34 becomes active */
     int BIP34Height;
     uint256 BIP34Hash;

src/consensus/tx_verify.cpp

@@ -140,7 +140,7 @@ unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& in
     return nSigOps;
 }
 
-int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, uint32_t flags)
+int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, script_verify_flags flags)
 {
     int64_t nSigOps = GetLegacySigOpCount(tx) * WITNESS_SCALE_FACTOR;
 

src/consensus/tx_verify.h

@@ -6,6 +6,7 @@
 #define BITCOIN_CONSENSUS_TX_VERIFY_H
 
 #include <consensus/amount.h>
+#include <script/verify_flags.h>
 
 #include <cstdint>
 #include <vector>
@@ -52,7 +53,7 @@ unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& ma
  * @param[in] flags Script verification flags
  * @return Total signature operation cost of tx
  */
-int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, uint32_t flags);
+int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, script_verify_flags flags);
 
 /**
  * Check if transaction is final and can be included in a block with the

src/policy/policy.h

@@ -98,7 +98,7 @@ static constexpr unsigned int MAX_DUST_OUTPUTS_PER_TX{1};
  * Note that this does not affect consensus validity; see GetBlockScriptFlags()
  * for that.
  */
-static constexpr unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS{SCRIPT_VERIFY_P2SH |
+static constexpr script_verify_flags MANDATORY_SCRIPT_VERIFY_FLAGS{SCRIPT_VERIFY_P2SH |
                                                              SCRIPT_VERIFY_DERSIG |
                                                              SCRIPT_VERIFY_NULLDUMMY |
                                                              SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY |
@@ -112,7 +112,7 @@ static constexpr unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS{SCRIPT_VERIFY_P2SH |
  * the additional (non-mandatory) rules here, to improve forwards and
  * backwards compatibility.
  */
-static constexpr unsigned int STANDARD_SCRIPT_VERIFY_FLAGS{MANDATORY_SCRIPT_VERIFY_FLAGS |
+static constexpr script_verify_flags STANDARD_SCRIPT_VERIFY_FLAGS{MANDATORY_SCRIPT_VERIFY_FLAGS |
                                                              SCRIPT_VERIFY_STRICTENC |
                                                              SCRIPT_VERIFY_MINIMALDATA |
                                                              SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS |
@@ -128,7 +128,7 @@ static constexpr unsigned int STANDARD_SCRIPT_VERIFY_FLAGS{MANDATORY_SCRIPT_VERI
                                                              SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE};
 
 /** For convenience, standard but not mandatory verify flags. */
-static constexpr unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS{STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS};
+static constexpr script_verify_flags STANDARD_NOT_MANDATORY_VERIFY_FLAGS{STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS};
 
 /** Used as the flags parameter to sequence and nLocktime checks in non-consensus code. */
 static constexpr unsigned int STANDARD_LOCKTIME_VERIFY_FLAGS{LOCKTIME_VERIFY_SEQUENCE};

src/script/interpreter.cpp

@@ -198,7 +198,7 @@ bool static IsDefinedHashtypeSignature(const valtype &vchSig) {
     return true;
 }
 
-bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror) {
+bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, script_verify_flags flags, ScriptError* serror) {
     // Empty signature. Not strictly DER encoded, but allowed to provide a
     // compact way to provide an invalid signature for use with CHECK(MULTI)SIG
     if (vchSig.size() == 0) {
@@ -215,7 +215,7 @@ bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned i
     return true;
 }
 
-bool static CheckPubKeyEncoding(const valtype &vchPubKey, unsigned int flags, const SigVersion &sigversion, ScriptError* serror) {
+bool static CheckPubKeyEncoding(const valtype &vchPubKey, script_verify_flags flags, const SigVersion &sigversion, ScriptError* serror) {
     if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsCompressedOrUncompressedPubKey(vchPubKey)) {
         return set_error(serror, SCRIPT_ERR_PUBKEYTYPE);
     }
@@ -318,7 +318,7 @@ class ConditionStack {
 };
 }
 
-static bool EvalChecksigPreTapscript(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)
+static bool EvalChecksigPreTapscript(const valtype& vchSig, const valtype& vchPubKey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& fSuccess)
 {
     assert(sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0);
 
@@ -344,7 +344,7 @@ static bool EvalChecksigPreTapscript(const valtype& vchSig, const valtype& vchPu
     return true;
 }
 
-static bool EvalChecksigTapscript(const valtype& sig, const valtype& pubkey, ScriptExecutionData& execdata, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success)
+static bool EvalChecksigTapscript(const valtype& sig, const valtype& pubkey, ScriptExecutionData& execdata, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success)
 {
     assert(sigversion == SigVersion::TAPSCRIPT);
 
@@ -389,7 +389,7 @@ static bool EvalChecksigTapscript(const valtype& sig, const valtype& pubkey, Scr
  * A return value of false means the script fails entirely. When true is returned, the
  * success variable indicates whether the signature check itself succeeded.
  */
-static bool EvalChecksig(const valtype& sig, const valtype& pubkey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, ScriptExecutionData& execdata, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success)
+static bool EvalChecksig(const valtype& sig, const valtype& pubkey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, ScriptExecutionData& execdata, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success)
 {
     switch (sigversion) {
     case SigVersion::BASE:
@@ -404,7 +404,7 @@ static bool EvalChecksig(const valtype& sig, const valtype& pubkey, CScript::con
     assert(false);
 }
 
-bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror)
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror)
 {
     static const CScriptNum bnZero(0);
     static const CScriptNum bnOne(1);
@@ -1234,7 +1234,7 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
     return set_success(serror);
 }
 
-bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)
 {
     ScriptExecutionData execdata;
     return EvalScript(stack, script, flags, checker, sigversion, execdata, serror);
@@ -1825,7 +1825,7 @@ bool GenericTransactionSignatureChecker<T>::CheckSequence(const CScriptNum& nSeq
 template class GenericTransactionSignatureChecker<CTransaction>;
 template class GenericTransactionSignatureChecker<CMutableTransaction>;
 
-static bool ExecuteWitnessScript(const std::span<const valtype>& stack_span, const CScript& exec_script, unsigned int flags, SigVersion sigversion, const BaseSignatureChecker& checker, ScriptExecutionData& execdata, ScriptError* serror)
+static bool ExecuteWitnessScript(const std::span<const valtype>& stack_span, const CScript& exec_script, script_verify_flags flags, SigVersion sigversion, const BaseSignatureChecker& checker, ScriptExecutionData& execdata, ScriptError* serror)
 {
     std::vector<valtype> stack{stack_span.begin(), stack_span.end()};
 
@@ -1910,7 +1910,7 @@ static bool VerifyTaprootCommitment(const std::vector<unsigned char>& control, c
     return q.CheckTapTweak(p, merkle_root, control[0] & 1);
 }
 
-static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion, const std::vector<unsigned char>& program, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror, bool is_p2sh)
+static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion, const std::vector<unsigned char>& program, script_verify_flags flags, const BaseSignatureChecker& checker, ScriptError* serror, bool is_p2sh)
 {
     CScript exec_script; //!< Actually executed script (last stack item in P2WSH; implied P2PKH script in P2WPKH; leaf script in P2TR)
     std::span stack{witness.stack};
@@ -1995,7 +1995,7 @@ static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion,
     // There is intentionally no return statement here, to be able to use "control reaches end of non-void function" warnings to detect gaps in the logic above.
 }
 
-bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror)
+bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, script_verify_flags flags, const BaseSignatureChecker& checker, ScriptError* serror)
 {
     static const CScriptWitness emptyWitness;
     if (witness == nullptr) {
@@ -2132,7 +2132,7 @@ size_t static WitnessSigOps(int witversion, const std::vector<unsigned char>& wi
     return 0;
 }
 
-size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags)
+size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, script_verify_flags flags)
 {
     static const CScriptWitness witnessEmpty;
 
@@ -2189,13 +2189,13 @@ const std::map<std::string, uint32_t> g_verify_flag_names{
 };
 #undef FLAG_NAME
 
-std::vector<std::string> GetScriptFlagNames(uint32_t flags)
+std::vector<std::string> GetScriptFlagNames(script_verify_flags flags)
 {
     std::vector<std::string> res;
     if (flags == SCRIPT_VERIFY_NONE) {
         return res;
     }
-    uint32_t leftover = flags;
+    script_verify_flags leftover = flags;
     for (const auto& [name, flag] : g_verify_flag_names) {
         if ((flags & flag) != 0) {
             res.push_back(name);

src/script/interpreter.h

@@ -10,6 +10,7 @@
 #include <hash.h>
 #include <primitives/transaction.h>
 #include <script/script_error.h> // IWYU pragma: export
+#include <script/verify_flags.h> // IWYU pragma: export
 #include <span.h>
 #include <uint256.h>
 
@@ -148,7 +149,7 @@ enum : uint32_t {
     SCRIPT_VERIFY_END_MARKER
 };
 
-bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror);
+bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, script_verify_flags flags, ScriptError* serror);
 
 struct PrecomputedTransactionData
 {
@@ -363,16 +364,16 @@ uint256 ComputeTapbranchHash(std::span<const unsigned char> a, std::span<const u
  *  Requires control block to have valid length (33 + k*32, with k in {0,1,..,128}). */
 uint256 ComputeTaprootMerkleRoot(std::span<const unsigned char> control, const uint256& tapleaf_hash);
 
-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);
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* error = nullptr);
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* error = nullptr);
+bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, script_verify_flags flags, const BaseSignatureChecker& checker, ScriptError* serror = nullptr);
 
-size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags);
+size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, script_verify_flags flags);
 
 int FindAndDelete(CScript& script, const CScript& b);
 
 extern const std::map<std::string, uint32_t> g_verify_flag_names;
 
-std::vector<std::string> GetScriptFlagNames(uint32_t flags);
+std::vector<std::string> GetScriptFlagNames(script_verify_flags flags);
 
 #endif // BITCOIN_SCRIPT_INTERPRETER_H

src/script/verify_flags.h

@@ -0,0 +1,13 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-present The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_SCRIPT_VERIFY_FLAGS_H
+#define BITCOIN_SCRIPT_VERIFY_FLAGS_H
+
+#include <cstdint>
+
+using script_verify_flags = uint32_t;
+
+#endif // BITCOIN_SCRIPT_VERIFY_FLAGS_H

src/signet.cpp

@@ -26,7 +26,7 @@
 
 static constexpr uint8_t SIGNET_HEADER[4] = {0xec, 0xc7, 0xda, 0xa2};
 
-static constexpr unsigned int BLOCK_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_NULLDUMMY;
+static constexpr script_verify_flags BLOCK_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_NULLDUMMY;
 
 static bool FetchAndClearCommitmentSection(const std::span<const uint8_t> header, CScript& witness_commitment, std::vector<uint8_t>& result)
 {

src/test/fuzz/eval_script.cpp

@@ -12,7 +12,7 @@
 FUZZ_TARGET(eval_script)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-    const unsigned int flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
+    const script_verify_flags flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
     const std::vector<uint8_t> script_bytes = [&] {
         if (fuzzed_data_provider.remaining_bytes() != 0) {
             return fuzzed_data_provider.ConsumeRemainingBytes<uint8_t>();