1 /*
2  * Copyright (C) 2019 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef INCLUDE_PERFETTO_EXT_BASE_WAITABLE_EVENT_H_
18 #define INCLUDE_PERFETTO_EXT_BASE_WAITABLE_EVENT_H_
19 
20 #include <condition_variable>
21 #include <mutex>
22 
23 namespace perfetto {
24 namespace base {
25 
26 // A waitable event for cross-thread synchronization.
27 // All methods on this class can be called from any thread.
28 class WaitableEvent {
29  public:
30   WaitableEvent();
31   ~WaitableEvent();
32   WaitableEvent(const WaitableEvent&) = delete;
33   WaitableEvent operator=(const WaitableEvent&) = delete;
34 
35   // Synchronously block until the event is notified.
36   void Wait();
37 
38   // Signal the event, waking up blocked waiters.
39   void Notify();
40 
41  private:
42   std::mutex mutex_;
43   std::condition_variable event_;
44   bool notified_ = false;
45 };
46 
47 }  // namespace base
48 }  // namespace perfetto
49 
50 #endif  // INCLUDE_PERFETTO_EXT_BASE_WAITABLE_EVENT_H_
51