// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright (C) 2005-2011, Jari Sundell <jaris@ifi.uio.no>

// A simple, and not guaranteed atomic, lockfile implementation. It
// saves the hostname and pid in the lock file, which may be accessed
// by Lockfile::locked_by(). If the path is an empty string then no
// lockfile will be created when Lockfile::try_lock() is called, still
// it will set the locked state of the Lockfile instance.

#ifndef RTORRENT_UTILS_LOCKFILE_H
#define RTORRENT_UTILS_LOCKFILE_H

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

namespace utils {

class Lockfile {
public:
  using process_type = std::pair<std::string, pid_t>;

  bool is_locked() const {
    return m_locked;
  }
  bool is_stale();

  // If the path is empty no lock file will be created, although
  // is_locked() will return true.
  bool try_lock();
  bool unlock();

  const std::string& path() const {
    return m_path;
  }
  void set_path(const std::string& path) {
    m_path = path;
  }

  std::string  locked_by_as_string() const;
  process_type locked_by() const;

private:
  std::string m_path;
  bool        m_locked{ false };
};

}

#endif
