1 /*
2  * Copyright (C) 2022 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #include "semaphore_utils.h"
17 
18 namespace utility {
Wait()19 void Semaphore::Wait()
20 {
21     std::unique_lock<std::mutex> lock(mutex_);
22     count_--;
23     if (count_ < 0) {
24         condVar_.wait(lock, [&]() -> bool { return wakeupnum_ > 0; });
25         wakeupnum_--;
26     }
27 }
28 
TryWait()29 bool Semaphore::TryWait()
30 {
31     std::unique_lock<std::mutex> lock(mutex_);
32     if (count_ <= 0) {
33         return false;
34     } else {
35         count_--;
36         return true;
37     }
38 }
39 
Post()40 void Semaphore::Post()
41 {
42     std::lock_guard<std::mutex> lock(mutex_);
43     count_++;
44     if (count_ <= 0) {
45         wakeupnum_++;
46         condVar_.notify_one();
47     }
48 }
49 }  // namespace utility