Migrate syntax reflection to new feature-based system.

PiperOrigin-RevId: 513358980

src/google/protobuf/compiler/cpp/helpers.cc

@@ -1092,10 +1092,6 @@ bool ShouldVerify(const FileDescriptor* file, const Options& options,
   return false;
 }
 
-bool IsUtf8String(const FieldDescriptor* field) {
-  return IsProto3(field->file()) &&
-         field->type() == FieldDescriptor::TYPE_STRING;
-}
 
 VerifySimpleType ShouldVerifySimple(const Descriptor* descriptor) {
   (void)descriptor;

src/google/protobuf/compiler/cpp/helpers.h

@@ -465,10 +465,6 @@ bool IsStringOrMessage(const FieldDescriptor* field);
 std::string UnderscoresToCamelCase(absl::string_view input,
                                    bool cap_next_letter);
 
-inline bool IsProto3(const FileDescriptor* file) {
-  return file->syntax() == FileDescriptor::SYNTAX_PROTO3;
-}
-
 inline bool IsCrossFileMessage(const FieldDescriptor* field) {
   return field->type() == FieldDescriptor::TYPE_MESSAGE &&
          field->message_type()->file() != field->file();
@@ -1045,8 +1041,6 @@ enum class VerifySimpleType {
 // Returns VerifySimpleType if messages can be verified by predefined methods.
 VerifySimpleType ShouldVerifySimple(const Descriptor* descriptor);
 
-bool IsUtf8String(const FieldDescriptor* field);
-
 bool HasMessageFieldOrExtension(const Descriptor* desc);
 
 // Generates a vector of substitutions for use with Printer::WithVars that

src/google/protobuf/compiler/cpp/message.cc

@@ -252,18 +252,6 @@ bool EmitFieldNonDefaultCondition(io::Printer* p, const std::string& prefix,
   return false;
 }
 
-// Does the given field have a has_$name$() method?
-bool HasHasMethod(const FieldDescriptor* field) {
-  if (!IsProto3(field->file())) {
-    // In proto1/proto2, every field has a has_$name$() method.
-    return true;
-  }
-  // For message types without true field presence, only fields with a message
-  // type or inside an one-of have a has_$name$() method.
-  return field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE ||
-         field->has_optional_keyword() || field->real_containing_oneof();
-}
-
 bool HasInternalHasMethod(const FieldDescriptor* field) {
   return !HasHasbit(field) &&
          field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE;
@@ -1040,7 +1028,7 @@ void MessageGenerator::GenerateOneofMemberHasBits(const FieldDescriptor* field,
   // N.B.: Without field presence, we do not use has-bits or generate
   // has_$name$() methods, but oneofs still have set_has_$name$().
   // Oneofs also have private _internal_has_$name$() a helper method.
-  if (HasHasMethod(field)) {
+  if (field->has_presence()) {
     format(
         "inline bool $classname$::has_$name$() const {\n"
         "$annotate_has$"
@@ -3651,7 +3639,8 @@ void MessageGenerator::GenerateSerializeWithCachedSizesBody(io::Printer* p) {
     LazySerializerEmitter(MessageGenerator* mg, io::Printer* p)
         : mg_(mg),
           p_(p),
-          eager_(IsProto3(mg->descriptor_->file())),
+          eager_(mg->descriptor_->file()->syntax() ==
+                 FileDescriptor::SYNTAX_PROTO3),
           cached_has_bit_index_(kNoHasbit) {}
 
     ~LazySerializerEmitter() { Flush(); }