src: use more explicit return type in Sign::SignFinal()

src/node_crypto.cc

@@ -3553,22 +3553,20 @@ static MallocedBuffer<unsigned char> Node_SignFinal(EVPMDPointer&& mdctx,
  return MallocedBuffer<unsigned char>();
 }
 
-std::pair<SignBase::Error, MallocedBuffer<unsigned char>> Sign::SignFinal(
+Sign::SignResult Sign::SignFinal(
  const char* key_pem,
  int key_pem_len,
  const char* passphrase,
  int padding,
  int salt_len) {
- MallocedBuffer<unsigned char> buffer;
-
  if (!mdctx_)
- return std::make_pair(kSignNotInitialised, std::move(buffer));
+ return SignResult(kSignNotInitialised);
 
  EVPMDPointer mdctx = std::move(mdctx_);
 
  BIOPointer bp(BIO_new_mem_buf(const_cast<char*>(key_pem), key_pem_len));
  if (!bp)
- return std::make_pair(kSignPrivateKey, std::move(buffer));
+ return SignResult(kSignPrivateKey);
 
  EVPKeyPointer pkey(PEM_read_bio_PrivateKey(bp.get(),
  nullptr,
@@ -3579,7 +3577,7 @@ std::pair<SignBase::Error, MallocedBuffer<unsigned char>> Sign::SignFinal(
  // without `pkey` being set to nullptr;
  // cf. the test of `test_bad_rsa_privkey.pem` for an example.
  if (!pkey || 0 != ERR_peek_error())
- return std::make_pair(kSignPrivateKey, std::move(buffer));
+ return SignResult(kSignPrivateKey);
 
 #ifdef NODE_FIPS_MODE
  /* Validate DSA2 parameters from FIPS 186-4 */
@@ -3603,9 +3601,10 @@ std::pair<SignBase::Error, MallocedBuffer<unsigned char>> Sign::SignFinal(
  }
 #endif // NODE_FIPS_MODE
 
- buffer = Node_SignFinal(std::move(mdctx), pkey, padding, salt_len);
+ MallocedBuffer<unsigned char> buffer =
+ Node_SignFinal(std::move(mdctx), pkey, padding, salt_len);
  Error error = buffer.is_empty() ? kSignPrivateKey : kSignOk;
- return std::make_pair(error, std::move(buffer));
+ return SignResult(error, std::move(buffer));
 }
 
 
@@ -3630,18 +3629,18 @@ void Sign::SignFinal(const FunctionCallbackInfo<Value>& args) {
 
  ClearErrorOnReturn clear_error_on_return;
 
- std::pair<Error, MallocedBuffer<unsigned char>> ret = sign->SignFinal(
+ SignResult ret = sign->SignFinal(
  buf,
  buf_len,
  len >= 2 && !args[1]->IsNull() ? *passphrase : nullptr,
  padding,
  salt_len);
 
- if (std::get<Error>(ret) != kSignOk)
- return sign->CheckThrow(std::get<Error>(ret));
+ if (ret.error != kSignOk)
+ return sign->CheckThrow(ret.error);
 
  MallocedBuffer<unsigned char> sig =
- std::move(std::get<MallocedBuffer<unsigned char>>(ret));
+ std::move(ret.signature);
 
  Local<Object> rc =
  Buffer::New(env, reinterpret_cast<char*>(sig.release()), sig.size)

src/node_crypto.h

@@ -518,7 +518,17 @@ class Sign : public SignBase {
  public:
  static void Initialize(Environment* env, v8::Local<v8::Object> target);
 
- std::pair<Error, MallocedBuffer<unsigned char>> SignFinal(
+ struct SignResult {
+ Error error;
+ MallocedBuffer<unsigned char> signature;
+
+ explicit SignResult(
+ Error err,
+ MallocedBuffer<unsigned char>&& sig = MallocedBuffer<unsigned char>())
+ : error(err), signature(std::move(sig)) {}
+ };
+
+ SignResult SignFinal(
  const char* key_pem,
  int key_pem_len,
  const char* passphrase,