Class AttributeQualifierStringPrinter

base/attribute.cc:75–112

Visitor for appending string representation for different qualifier kinds.

// Visitor for appending string representation for different qualifier kinds.
class AttributeQualifierStringPrinter {
 public:
  // String representation for the given qualifier is appended to output.
  explicit AttributeQualifierStringPrinter(std::string* absl_nonnull output,
                                           Kind type)
      : output_(*output), type_(type) {}

  absl::Status operator()(const Kind& ignored) const {
    // Attributes are represented as a variant, with illegal attribute
    // qualifiers represented with their type as the first alternative.
    return absl::InvalidArgumentError(
        absl::StrCat("Unsupported attribute qualifier ", KindToString(type_)));
  }

  absl::Status operator()(int64_t index) {
    absl::StrAppend(&output_, index);
    return absl::OkStatus();
  }

  absl::Status operator()(uint64_t index) {
    absl::StrAppend(&output_, index);
    return absl::OkStatus();
  }

  absl::Status operator()(bool bool_key) {
    absl::StrAppend(&output_, (bool_key) ? "true" : "false");
    return absl::OkStatus();
  }

  absl::Status operator()(const std::string& field) {
    absl::StrAppend(&output_, field);
    return absl::OkStatus();
  }

 private:
  std::string& output_;
  Kind type_;
};

struct AttributeQualifierTypeVisitor final {
  Kind operator()(const Kind& type) const { return type; }