xref: /aosp_15_r20/external/abseil-cpp/absl/synchronization/internal/stdcpp_waiter.h (revision 9356374a3709195abf420251b3e825997ff56c0f)

// Copyright 2023 The Abseil Authors.
//
// 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
//
//      https://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 ABSL_SYNCHRONIZATION_INTERNAL_STDCPP_WAITER_H_
#define ABSL_SYNCHRONIZATION_INTERNAL_STDCPP_WAITER_H_

#include <condition_variable>  // NOLINT(build/c++11)
#include <mutex>  // NOLINT(build/c++11)

#include "absl/base/config.h"
#include "absl/synchronization/internal/kernel_timeout.h"
#include "absl/synchronization/internal/waiter_base.h"

namespace absl {
ABSL_NAMESPACE_BEGIN
namespace synchronization_internal {

#define ABSL_INTERNAL_HAVE_STDCPP_WAITER 1

class StdcppWaiter : public WaiterCrtp<StdcppWaiter> {
 public:
  StdcppWaiter();

  bool Wait(KernelTimeout t);
  void Post();
  void Poke();

  static constexpr char kName[] = "StdcppWaiter";

 private:
  // REQUIRES: mu_ must be held.
  void InternalCondVarPoke();

  std::mutex mu_;
  std::condition_variable cv_;
  int waiter_count_;
  int wakeup_count_;  // Unclaimed wakeups.
};

}  // namespace synchronization_internal
ABSL_NAMESPACE_END
}  // namespace absl

#endif  // ABSL_SYNCHRONIZATION_INTERNAL_STDCPP_WAITER_H_