1/*
2 * Copyright (c) Huawei Technologies Co., Ltd. 2021. All rights reserved.
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
17StdSemaphore::StdSemaphore(unsigned int value) : value_(value) {}
18
19StdSemaphore::~StdSemaphore() {}
20
21bool 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
31bool StdSemaphore::TryWait()
32{
33    std::unique_lock<std::mutex> lock(mutex_);
34    return TryWaitLocked();
35}
36
37bool StdSemaphore::TryWaitLocked()
38{
39    if (value_ == 0) {
40        return false;
41    }
42    --value_;
43    return true;
44}
45
46bool 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
58bool StdSemaphore::Post()
59{
60    {
61        std::unique_lock<std::mutex> lock(mutex_);
62        ++value_;
63    }
64    condVar_.notify_all();
65    return true;
66}
67
68unsigned StdSemaphore::Value() const
69{
70    return value_;
71}
72
73SemaphorePtr StdSemaphoreFactory::Create(unsigned int value)
74{
75    return std::make_shared<StdSemaphore>(value);
76}
77