1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
/*
* Copyright (C) 2007 The Android Open Source Project
*
* 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.
*/
#ifndef ANDROID_BARRIER_H
#define ANDROID_BARRIER_H
#include <stdint.h>
#include <condition_variable>
#include <mutex>
namespace android {
class Barrier
{
public:
// Release any threads waiting at the Barrier.
// Provides release semantics: preceding loads and stores will be visible
// to other threads before they wake up.
void open() {
std::lock_guard<std::mutex> lock(mMutex);
mIsOpen = true;
mCondition.notify_all();
}
// Reset the Barrier, so wait() will block until open() has been called.
void close() {
std::lock_guard<std::mutex> lock(mMutex);
mIsOpen = false;
}
// Wait until the Barrier is OPEN.
// Provides acquire semantics: no subsequent loads or stores will occur
// until wait() returns.
void wait() const {
std::unique_lock<std::mutex> lock(mMutex);
mCondition.wait(lock, [this]() NO_THREAD_SAFETY_ANALYSIS { return mIsOpen; });
}
private:
mutable std::mutex mMutex;
mutable std::condition_variable mCondition;
int mIsOpen GUARDED_BY(mMutex){false};
};
}; // namespace android
#endif // ANDROID_BARRIER_H
|
