virtual bool HasCustomDeviceInput() const = 0;

  virtual const tensorflow::OpDef* OpDef() const = 0;

  virtual Status InputLength(const char* input_name, int* length) = 0;
  virtual Status OutputLength(const char* output_name, int* length) = 0;

  // Set stack trace to be used for potential async error reporting.
  virtual void SetStackTrace(ManagedStackTrace stack_trace) = 0;

}  // namespace tf_writable_file

namespace tf_read_only_memory_region {
void Cleanup(TF_ReadOnlyMemoryRegion* region);
const void* Data(const TF_ReadOnlyMemoryRegion* region);
uint64_t Length(const TF_ReadOnlyMemoryRegion* region);
}  // namespace tf_read_only_memory_region

namespace tf_gcs_filesystem {
typedef struct GcsFileStat {
  TF_FileStatistics base;
  int64_t generation_number;
} GcsFileStat;

// status.
TF_CAPI_EXPORT extern void TF_AppendWritableFile(TF_WritableFileHandle* handle,
                                                 const char* data,
                                                 size_t length,
                                                 TF_Status* status);

// Deletes the named file and indicates whether successful in *status.
TF_CAPI_EXPORT extern void TF_DeleteFile(const char* filename,

  Status SetAttrFunctionName(const char* attr_name, const char* value,
                             size_t length) override;
  Status SetAttrTensor(const char* attr_name,
                       AbstractTensorInterface* tensor) override;
  Status SetAttrStringList(const char* attr_name, const void* const* values,
                           const size_t* lengths, int num_values) override;
  Status SetAttrFloatList(const char* attr_name, const float* values,

  std::vector<size_t> lengths;
  raw_strs.reserve(values.size());
  lengths.reserve(values.size());
  for (const auto& s : values) {
    raw_strs.emplace_back(s.data());
    lengths.emplace_back(s.size());
  }
  return SetAttrStringList(attr_name,
                           reinterpret_cast<const void**>(raw_strs.data()),
                           lengths.data(), values.size());
}

    return 1;
  }

  char file_name[100];
  time_t t = time(NULL);
  snprintf(file_name, sizeof(file_name), "test-%d-%ld.txt", getpid(), t);

  size_t length = 2 + strlen(path) + strlen(file_name);
  char* full_path = malloc(length);
  snprintf(full_path, length, "%s/%s", path, file_name);

  TF_WritableFileHandle* h;
  TF_Status* status = TF_NewStatus();
  TF_NewWritableFile(full_path, &h, status);

                           const char* value, size_t length, ForwardOperation*);
Status SetAttrTensor(AbstractOperation*, const char* attr_name,
                     AbstractTensorInterface* tensor, ForwardOperation*);
Status SetAttrStringList(AbstractOperation*, const char* attr_name,
                         const void* const* values, const size_t* lengths,
                         int num_values, ForwardOperation*);

      : region_(std::move(region)), ops_(ops) {}

  ~ModularReadOnlyMemoryRegion() override { ops_->cleanup(region_.get()); };

  const void* data() override { return ops_->data(region_.get()); }
  uint64 length() override { return ops_->length(region_.get()); }

 private:
  std::unique_ptr<TF_ReadOnlyMemoryRegion> region_;
  const TF_ReadOnlyMemoryRegionOps* ops_;  // not owned

namespace tensorflow {

// Set the shapes and types of the output's handle.
//
// The lengths of the arrays pointed to by `shapes`, `ranks`, and `types` must
// all be equal to `num_shapes_and_types`. If `ranks[i] != -1`, (i.e., if the
// rank is known), then it must be equal to the length of `shapes[i]`; if
// `ranks[i] == 1`, then `shapes[i]` may be nullptr.
//

  // Returns number of elements across all dimensions.
  virtual Status NumElements(int64_t* num_elements) const = 0;
  // Returns size of specified dimension
  //
  // -1 indicates an unknown axis length; this is unreachable for most standard
  // ImmediateExecutionTensorHandles, but comes up for example when computing
  // the shape of a parallel tensor with component shapes differing across
  // devices.