/* Copyright 2016 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

/// SavedModel loading functions and SavedModelBundle struct.

#ifndef TENSORFLOW_CC_SAVED_MODEL_LOADER_H_
#define TENSORFLOW_CC_SAVED_MODEL_LOADER_H_

#include <string>
#include <unordered_set>

#include "tensorflow/core/lib/core/status.h"
#include "tensorflow/core/protobuf/meta_graph.pb.h"
#include "tensorflow/core/public/session.h"

namespace tensorflow {

/// SavedModel representation once the SavedModel is loaded from storage.
struct SavedModelBundle {
  std::unique_ptr<Session> session;
  MetaGraphDef meta_graph_def;

  /// A TensorFlow Session does not Close itself on destruction. To avoid
  /// resource leaks, we explicitly call Close on Sessions that we create.
  ~SavedModelBundle() {
    if (session) {
      session->Close().IgnoreError();
    }
  }

  SavedModelBundle() = default;
};

/// Loads a SavedModel from the specified export directory. The meta graph def
/// to be loaded is identified by the supplied tags, corresponding exactly to
/// the set of tags used at SavedModel build time. Returns a SavedModel bundle
/// with a session and the requested meta graph def, if found.
Status LoadSavedModel(const SessionOptions& session_options,
                      const RunOptions& run_options, const string& export_dir,
                      const std::unordered_set<string>& tags,
                      SavedModelBundle* const bundle);

/// Checks whether the provided directory could contain a SavedModel. Note that
/// the method does not load any data by itself. If the method returns `false`,
/// the export directory definitely does not contain a SavedModel. If the method
/// returns `true`, the export directory may contain a SavedModel but provides
/// no guarantee that it can be loaded.
bool MaybeSavedModelDirectory(const string& export_dir);

}  // namespace tensorflow

#endif  // TENSORFLOW_CC_SAVED_MODEL_LOADER_H_