Class DummyFileFormat

cpp/src/arrow/dataset/test_util_internal.h:1577–1614

\brief A dummy FileFormat implementation

/// \brief A dummy FileFormat implementation
class DummyFileFormat : public FileFormat {
 public:
  explicit DummyFileFormat(std::shared_ptr<Schema> schema = NULLPTR)
      : FileFormat(/*default_fragment_scan_options=*/nullptr),
        schema_(std::move(schema)) {}

  std::string type_name() const override { return "dummy"; }

  bool Equals(const FileFormat& other) const override {
    return type_name() == other.type_name() &&
           schema_->Equals(checked_cast<const DummyFileFormat&>(other).schema_);
  }

  Result<bool> IsSupported(const FileSource& source) const override { return true; }

  Result<std::shared_ptr<Schema>> Inspect(const FileSource& source) const override {
    return schema_;
  }

  /// \brief Open a file for scanning (always returns an empty generator)
  Result<RecordBatchGenerator> ScanBatchesAsync(
      const std::shared_ptr<ScanOptions>& options,
      const std::shared_ptr<FileFragment>& fragment) const override {
    return MakeEmptyGenerator<std::shared_ptr<RecordBatch>>();
  }

  Result<std::shared_ptr<FileWriter>> MakeWriter(
      std::shared_ptr<io::OutputStream> destination, std::shared_ptr<Schema> schema,
      std::shared_ptr<FileWriteOptions> options,
      fs::FileLocator destination_locator) const override {
    return Status::NotImplemented("writing fragment of DummyFileFormat");
  }

  std::shared_ptr<FileWriteOptions> DefaultWriteOptions() override { return nullptr; }

 protected:
  std::shared_ptr<Schema> schema_;
};

class JSONRecordBatchFileFormat : public FileFormat {
 public: