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/*
* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_ONE_TIME_EVENT_H_
#define RTC_BASE_ONE_TIME_EVENT_H_
#include "rtc_base/synchronization/mutex.h"
namespace webrtc {
// Provides a simple way to perform an operation (such as logging) one
// time in a certain scope.
// Example:
// OneTimeEvent firstFrame;
// ...
// if (firstFrame()) {
// RTC_LOG(LS_INFO) << "This is the first frame".
// }
class OneTimeEvent {
public:
OneTimeEvent() {}
bool operator()() {
MutexLock lock(&mutex_);
if (happened_) {
return false;
}
happened_ = true;
return true;
}
private:
bool happened_ = false;
Mutex mutex_;
};
// A non-thread-safe, ligher-weight version of the OneTimeEvent class.
class ThreadUnsafeOneTimeEvent {
public:
ThreadUnsafeOneTimeEvent() {}
bool operator()() {
if (happened_) {
return false;
}
happened_ = true;
return true;
}
private:
bool happened_ = false;
};
} // namespace webrtc
#endif // RTC_BASE_ONE_TIME_EVENT_H_
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