| /* |
| * 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_ONETIMEEVENT_H_ |
| #define RTC_BASE_ONETIMEEVENT_H_ |
| |
| #include "rtc_base/criticalsection.h" |
| #include "typedefs.h" // NOLINT(build/include) |
| |
| 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()() { |
| rtc::CritScope cs(&critsect_); |
| if (happened_) { |
| return false; |
| } |
| happened_ = true; |
| return true; |
| } |
| |
| private: |
| bool happened_ = false; |
| rtc::CriticalSection critsect_; |
| }; |
| |
| // 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_ONETIMEEVENT_H_ |