mindspore2022/mindspore/ccsrc/minddata/dataset/callback/callback_manager.h

/**
 * Copyright 2020 Huawei Technologies Co., Ltd
 *
 * 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.
 */

#ifndef MINDSPORE_CCSRC_MINDDATA_DATASET_CALLBACK_MANAGER_H
#define MINDSPORE_CCSRC_MINDDATA_DATASET_CALLBACK_MANAGER_H

#include <memory>
#include <vector>

#include "minddata/dataset/callback/ds_callback.h"
#include "minddata/dataset/util/status.h"

namespace mindspore {
namespace dataset {

// forward declare to avoid cyclic include of dataset_op.h
class DatasetOp;

/// This class manages all the callbacks that are associated with a single DatasetOp. For now, only MapOp supports this.
class CallbackManager {
 public:
  /// \brief CallbackManager default constructor. Init needs to be called before using the created instance.
  CallbackManager() : enabled_(false) {}

  ~CallbackManager() = default;

  /// \brief
  /// \param [in] callbacks list of callbacks to perform
  void AddCallbacks(std::vector<std::shared_ptr<DSCallback>> callbacks);

  /// \brief set callbacks to empty
  void ClearCallbacks() { callbacks_.clear(); }

  /// \brief DatasetOp needs to call Init if it wishes to use callback, Init will set enabled_ to true
  /// \param[in] op, this pointer is used for Callback Manager to Pause Worker threads
  /// \return Status
  Status Init(DatasetOp *op);

  /// \brief callback function called at the start of the first row
  /// \return Status
  Status Begin(const CallbackParam &);

  /// \brief callback function called at the start of each epoch
  /// \return Status
  Status EpochBegin(const CallbackParam &);

  /// \brief callback function called at the start of each row
  /// \return Status
  Status StepBegin(const CallbackParam &);

  /// \brief callback function called after the last row is processed
  /// \return Status
  Status End(const CallbackParam &);

  /// \brief callback function called at the end of each epoch
  /// \return Status
  Status EpochEnd(const CallbackParam &);

  /// \brief callback function called at the the end of each row
  /// \return Status
  Status StepEnd(const CallbackParam &);

 private:
  bool enabled_;   // flag to enable callback, if false, all functions would return immediately
  DatasetOp *op_;  // back pointer to DatasetOp, raw pointer to avoid circular ownership
  std::vector<std::shared_ptr<DSCallback>> callbacks_;  // list of callbacks the  DatasetOp needs to call
};
}  // namespace dataset
}  // namespace mindspore

#endif  // MINDSPORE_CCSRC_MINDDATA_DATASET_CALLBACK_MANAGER_H