tlbmc/utils/inotify_watcher.h

#ifndef THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_UTILS_INOTIFY_WATCHER_H_
#define THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_UTILS_INOTIFY_WATCHER_H_

#include <atomic>
#include <cstdint>
#include <functional>
#include <memory>
#include <string>
#include <vector>

#include "absl/base/thread_annotations.h"
#include "absl/container/flat_hash_map.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/string_view.h"
#include "absl/synchronization/mutex.h"
#include "boost/asio.hpp"  // NOLINT

namespace milotic_tlbmc {

class InotifyWatcher : public std::enable_shared_from_this<InotifyWatcher> {
 public:
  using EventCallback = std::function<void(
      absl::string_view dir_path, absl::string_view filename, uint32_t mask)>;

  static absl::StatusOr<std::shared_ptr<InotifyWatcher>> Create(
      std::shared_ptr<boost::asio::io_context> io_context,
      EventCallback callback);

  ~InotifyWatcher();

  absl::Status WatchDirectory(std::string dir_path, uint32_t event_mask);
  void Stop();

 private:
  InotifyWatcher(std::shared_ptr<boost::asio::io_context> io_context,
                 EventCallback callback, int fd);

  void StartAsyncRead();
  void HandleRead(const boost::system::error_code& error,
                  std::size_t bytes_transferred);

  std::atomic<int> inotify_fd_ = -1;
  absl::Mutex mutex_;
  absl::flat_hash_map<int, std::string> watch_descriptors_
      ABSL_GUARDED_BY(mutex_);
  std::shared_ptr<boost::asio::io_context> io_context_;
  boost::asio::posix::stream_descriptor stream_descriptor_;
  std::vector<uint8_t> read_buffer_;
  EventCallback callback_;
  std::atomic<bool> stopped_{false};
};

}  // namespace milotic_tlbmc

#endif  // THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_UTILS_INOTIFY_WATCHER_H_