camera/include/cros-camera/future_internal.h

/*
 * Copyright 2016 The ChromiumOS Authors
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef CAMERA_INCLUDE_CROS_CAMERA_FUTURE_INTERNAL_H_
#define CAMERA_INCLUDE_CROS_CAMERA_FUTURE_INTERNAL_H_

#include <base/synchronization/condition_variable.h>
#include <base/synchronization/lock.h>

#include "cros-camera/export.h"

namespace cros {

class CancellationRelay;

namespace internal {

class CROS_CAMERA_EXPORT FutureLock {
 public:
  explicit FutureLock(CancellationRelay* relay);
  FutureLock(const FutureLock&) = delete;
  FutureLock& operator=(const FutureLock&) = delete;

  ~FutureLock();

  void Signal();

  /* Default timeout is set to 5 seconds.  Setting the timeout to a value less
   * than or equal to 0 will wait indefinitely until the value is set.
   */
  bool Wait(int timeout_ms = 5000);

  void Cancel();

 private:
  /* Used to serialize all member access. */
  base::Lock lock_;

  base::ConditionVariable cond_;

  /* Used to indicate that the FutureLock is cancelled. */
  bool cancelled_;

  /* Used to indicate that the FutureLock is signalled. */
  bool signalled_;

  /* Registerred by FutureLock to receive cancel signal */
  CancellationRelay* relay_;
};

}  // namespace internal

}  // namespace cros

#endif  // CAMERA_INCLUDE_CROS_CAMERA_FUTURE_INTERNAL_H_