Class DatasetVariantWrapper

tensorflow/core/framework/dataset.cc:41–87

A wrapper class for storing a `DatasetBase` instance in a DT_VARIANT tensor. Objects of the wrapper class own a reference on an instance of `DatasetBase`, and the wrapper's copy constructor and destructor take care of managing the reference count. NOTE(mrry): This is not a feature-complete implementation of the DT_VARIANT specification. In particular, we cannot currently serialize an arbitrary `D

// `DatasetBase` object, so the `Encode()` and `Decode()` methods are not
// implemented.
class DatasetVariantWrapper {
 public:
  DatasetVariantWrapper() : dataset_(nullptr) {}

  // Transfers ownership of `dataset` to `*this`.
  explicit DatasetVariantWrapper(DatasetBase* dataset) : dataset_(dataset) {}

  DatasetVariantWrapper(const DatasetVariantWrapper& other)
      : dataset_(other.dataset_) {
    if (dataset_) dataset_->Ref();
  }

  DatasetVariantWrapper& operator=(DatasetVariantWrapper&& other) {
    if (&other == this) return *this;
    std::swap(dataset_, other.dataset_);
    return *this;
  }

  DatasetVariantWrapper& operator=(const DatasetVariantWrapper& other) = delete;

  ~DatasetVariantWrapper() {
    if (dataset_) dataset_->Unref();
  }

  DatasetBase* get() const { return dataset_; }

  string TypeName() const { return "tensorflow::DatasetVariantWrapper"; }
  string DebugString() const {
    if (dataset_) {
      return dataset_->DebugString();
    } else {
      return "<Uninitialized DatasetVariantWrapper>";
    }
  }
  void Encode(VariantTensorData* data) const {
    LOG(ERROR) << "The Encode() method is not implemented for "
                  "DatasetVariantWrapper objects.";
  }
  bool Decode(const VariantTensorData& data) {
    LOG(ERROR) << "The Decode() method is not implemented for "
                  "DatasetVariantWrapper objects.";
    return false;
  }

 private:
  DatasetBase* dataset_;  // Owns one reference.
};

const char kWrappedDatasetVariantTypeName[] =
    "tensorflow::data::WrappedDatasetVariant";