YugabyteDB (2.13.1.0-b60, 21121d69985fbf76aa6958d8f04a9bfa936293b5)

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

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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

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#ifndef YB_UTIL_SEMAPHORE_H

#define YB_UTIL_SEMAPHORE_H

#include <semaphore.h>

#if defined(__APPLE__)

#include <dispatch/dispatch.h>

#include "yb/util/atomic.h"

#endif  // define(__APPLE__)

#include "yb/gutil/macros.h"

#include "yb/gutil/port.h"

#include "yb/util/monotime.h"

namespace yb {

// Wrapper for POSIX semaphores.

class Semaphore {

 public:

  // Initialize the semaphore with the specified capacity.

  explicit Semaphore(int capacity);

  ~Semaphore();

  // Acquire the semaphore.

  void Acquire();

  // Acquire the semaphore within the given timeout. Returns true if successful.

  bool TimedAcquire(const MonoDelta& timeout);

  // Try to acquire the semaphore immediately. Returns false if unsuccessful.

  bool TryAcquire();

  // Release the semaphore.

  void Release();

  // Get the current value of the semaphore.

  int GetValue();

  // Boost-compatible wrappers.

  void lock() { Acquire(); }

  void unlock() { Release(); }

  bool try_lock() { return TryAcquire(); }

 private:

#if !defined(__APPLE__)

  // Log a fatal error message. Separated out to keep the main functions

  // as small as possible in terms of code size.

  void Fatal(const char* action) ATTRIBUTE_NORETURN;

#endif  // !define(__APPLE__)

#if defined(__APPLE__)

  std::atomic<int32_t> count_;

  std::condition_variable cv_;

  // Mutex to use with the condition variable cv_.

  std::mutex mutex_;

#else

  sem_t sem_;

#endif  // define(__APPLE__)

  DISALLOW_COPY_AND_ASSIGN(Semaphore);

};

} // namespace yb

#endif /* YB_UTIL_SEMAPHORE_H */