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1 /*
2  * Copyright (c) 2021 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 #include "std_semaphore.h"
16 
StdSemaphore(unsigned int value)17 StdSemaphore::StdSemaphore(unsigned int value) : value_(value) {}
18 
~StdSemaphore()19 StdSemaphore::~StdSemaphore() {}
20 
Wait()21 bool StdSemaphore::Wait()
22 {
23     std::unique_lock<std::mutex> lock(mutex_);
24     while (value_ == 0) {
25         condVar_.wait(lock);
26     }
27     --value_;
28     return true;
29 }
30 
TryWait()31 bool StdSemaphore::TryWait()
32 {
33     std::unique_lock<std::mutex> lock(mutex_);
34     return TryWaitLocked();
35 }
36 
TryWaitLocked()37 bool StdSemaphore::TryWaitLocked()
38 {
39     if (value_ == 0) {
40         return false;
41     }
42     --value_;
43     return true;
44 }
45 
TimedWait(int seconds,int nanoSeconds)46 bool StdSemaphore::TimedWait(int seconds, int nanoSeconds)
47 {
48     std::unique_lock<std::mutex> lock(mutex_);
49     if (value_ == 0) {
50         auto timePoint = std::chrono::steady_clock::now();
51         timePoint += std::chrono::seconds(seconds);
52         timePoint += std::chrono::nanoseconds(nanoSeconds);
53         condVar_.wait_until(lock, timePoint);
54     }
55     return TryWaitLocked();
56 }
57 
Post()58 bool StdSemaphore::Post()
59 {
60     {
61         std::unique_lock<std::mutex> lock(mutex_);
62         ++value_;
63     }
64     condVar_.notify_all();
65     return true;
66 }
67 
Value() const68 unsigned StdSemaphore::Value() const
69 {
70     return value_;
71 }
72 
Create(unsigned int value)73 SemaphorePtr StdSemaphoreFactory::Create(unsigned int value)
74 {
75     return std::make_shared<StdSemaphore>(value);
76 }
77