YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

// Licensed to the Apache Software Foundation (ASF) under one

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// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

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

//

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// specific language governing permissions and limitations

// under the License.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// 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

//

// http://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.

//

#include <semaphore.h>

#include <glog/logging.h>

#include "yb/util/semaphore.h"

namespace yb {

Semaphore::Semaphore(int capacity)

  : count_(capacity) {

  DCHECK_GE(capacity, 0);

}

Semaphore::~Semaphore() {

}

void Semaphore::Acquire() {

  std::unique_lock<std::mutex> lock(mutex_);

  cv_.wait(lock, [this] { return count_.load() > 0; });

  CHECK_GT(count_.load(), 0);

  count_.fetch_sub(1);

}

bool Semaphore::TryAcquire() {

  if (count_.load() > 0) {

    std::unique_lock<std::mutex> lock(mutex_);

    if (count_.load() > 0) {

      count_.fetch_sub(1);

      return true;

    }

  }

  return false;

}

bool Semaphore::TimedAcquire(const MonoDelta& timeout) {

  auto time_stop = MonoTime::Now();

  time_stop.AddDelta(timeout);

  std::unique_lock<std::mutex> lock(mutex_);

  if (!cv_.wait_until(lock, time_stop.ToSteadyTimePoint(), [this] { return count_.load() > 0; })) {

    return false;

  }

  CHECK_GT(count_.load(), 0);

  count_.fetch_sub(1);

  return true;

}

void Semaphore::Release() {

  std::unique_lock<std::mutex> lock(mutex_);

  CHECK_GE(count_.load(), 0);

  count_.fetch_add(1);

  cv_.notify_all();

}

int Semaphore::GetValue() {

  return count_.load();

}

} // namespace yb