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// Copyright 2020 Google LLC
//
// 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.
#include "platform/impl/shared/count_down_latch.h"
namespace location {
namespace nearby {
namespace shared {
// A synchronization aid that allows one or more threads to wait until a set of
// operations being performed in other threads completes.
//
// https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CountDownLatch.html
CountDownLatch::CountDownLatch(int count) : count_(count) {}
ExceptionOr<bool> CountDownLatch::Await(absl::Duration timeout) {
absl::MutexLock lock(&mutex_);
absl::Time deadline = absl::Now() + timeout;
while (count_ > 0) {
if (cond_.WaitWithDeadline(&mutex_, deadline)) {
return ExceptionOr<bool>(false);
}
}
return ExceptionOr<bool>(true);
}
Exception CountDownLatch::Await() {
absl::MutexLock lock(&mutex_);
while (count_ > 0) {
cond_.Wait(&mutex_);
}
return {Exception::kSuccess};
}
void CountDownLatch::CountDown() {
absl::MutexLock lock(&mutex_);
if (count_ > 0 && --count_ == 0) {
cond_.SignalAll();
}
}
} // namespace shared
} // namespace nearby
} // namespace location