Program Listing for File file_fifo_mutex.hpp

            

            
/*
* SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
* SPDX-License-Identifier: Apache-2.0
*
* 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 HOLOSCAN_CORE_FILE_FIFO_MUTEX_HPP
#define HOLOSCAN_CORE_FILE_FIFO_MUTEX_HPP

#include <sys/types.h>
#include <memory>
#include <string>
#include <utility>

namespace holoscan {
constexpr int DEFAULT_FIFOMUTEX_WAIT_TIME_MS = 10;

class ScopedFlock {
 public:
  // Deleting default constructors
  ScopedFlock() = delete;
  ScopedFlock(const ScopedFlock&) = delete;
  ScopedFlock& operator=(const ScopedFlock&) = delete;

  ScopedFlock(int fd, int lock_type, int unlock_type);
  ~ScopedFlock();
  bool locked() const { return locked_; }

 private:
  int fd_ = -1;
  int unlock_type_;
  bool locked_ = false;
};

class ScopedWaitedFlock {
 public:
  // Deleting default constructors
  ScopedWaitedFlock() = delete;
  ScopedWaitedFlock(const ScopedWaitedFlock&) = delete;
  ScopedWaitedFlock& operator=(const ScopedWaitedFlock&) = delete;

  ScopedWaitedFlock(int fd, int lock_type, int unlock_type,
                    int wait_time_ms = DEFAULT_FIFOMUTEX_WAIT_TIME_MS);
  ~ScopedWaitedFlock() = default;

  bool locked() const { return scoped_lock_ && scoped_lock_->locked(); }

 private:
  std::unique_ptr<ScopedFlock> scoped_lock_;
};

class FileFIFOMutex {
 public:
  // Delete default, copy and assignment constructors
  FileFIFOMutex(const FileFIFOMutex&) = delete;
  FileFIFOMutex& operator=(const FileFIFOMutex&) = delete;
  FileFIFOMutex() = delete;
  explicit FileFIFOMutex(std::string file_path);

  ~FileFIFOMutex();
  void set_wait_time_ms(int wait_time_ms);

  void lock();
  void unlock();
  bool locked() const;

 private:
  std::unique_ptr<ScopedFlock> main_lock_;
  int fd_ = -1;
  int queue_fd_ = -1;
  pid_t pid_;
  bool locked_ = false;
  int wait_time_ms_ = DEFAULT_FIFOMUTEX_WAIT_TIME_MS;
};
}  // namespace holoscan

#endif/* HOLOSCAN_CORE_FILE_FIFO_MUTEX_HPP */