Function WrapFieldImpl

common/value.cc:1497–1631

template <typename Unsafe>
Value WrapFieldImpl(
    ProtoWrapperTypeOptions wrapper_type_options,
    const google::protobuf::Message* absl_nonnull message ABSL_ATTRIBUTE_LIFETIME_BOUND,
    const google::protobuf::FieldDescriptor* absl_nonnull field
        ABSL_ATTRIBUTE_LIFETIME_BOUND,
    const google::protobuf::DescriptorPool* absl_nonnull descriptor_pool
        ABSL_ATTRIBUTE_LIFETIME_BOUND,
    google::protobuf::MessageFactory* absl_nonnull message_factory
        ABSL_ATTRIBUTE_LIFETIME_BOUND,
    google::protobuf::Arena* absl_nonnull arena ABSL_ATTRIBUTE_LIFETIME_BOUND) {
  ABSL_DCHECK(field != nullptr);
  ABSL_DCHECK_EQ(message->GetDescriptor(), field->containing_type());
  ABSL_DCHECK(descriptor_pool != nullptr);
  ABSL_DCHECK(message_factory != nullptr);
  ABSL_DCHECK(!IsWellKnownMessageType(message->GetDescriptor()));

  const auto* reflection = message->GetReflection();
  if (field->is_map()) {
    if (reflection->FieldSize(*message, field) == 0) {
      return MapValue();
    }
    if constexpr (Unsafe::value) {
      return UnsafeParsedMapFieldValue(message, field);
    } else {
      return ParsedMapFieldValue(message, field,
                                 MessageArenaOr(message, arena));
    }
  }
  if (field->is_repeated()) {
    if (reflection->FieldSize(*message, field) == 0) {
      return ListValue();
    }
    if constexpr (Unsafe::value) {
      return UnsafeParsedRepeatedFieldValue(message, field);
    } else {
      return ParsedRepeatedFieldValue(message, field,
                                      MessageArenaOr(message, arena));
    }
  }
  switch (field->type()) {
    case google::protobuf::FieldDescriptor::TYPE_DOUBLE:
      return DoubleValue(reflection->GetDouble(*message, field));
    case google::protobuf::FieldDescriptor::TYPE_FLOAT:
      return DoubleValue(reflection->GetFloat(*message, field));
    case google::protobuf::FieldDescriptor::TYPE_INT64:
      return IntValue(reflection->GetInt64(*message, field));
    case google::protobuf::FieldDescriptor::TYPE_UINT64:
      return UintValue(reflection->GetUInt64(*message, field));
    case google::protobuf::FieldDescriptor::TYPE_INT32:
      return IntValue(reflection->GetInt32(*message, field));
    case google::protobuf::FieldDescriptor::TYPE_FIXED64:
      return UintValue(reflection->GetUInt64(*message, field));
    case google::protobuf::FieldDescriptor::TYPE_FIXED32:
      return UintValue(reflection->GetUInt32(*message, field));
    case google::protobuf::FieldDescriptor::TYPE_BOOL:
      return BoolValue(reflection->GetBool(*message, field));
    case google::protobuf::FieldDescriptor::TYPE_STRING: {
      std::string scratch;