docs/zh-cn/c-utils-guide-safe_block_queue.md · OpenHarmony/commonlibrary_c_utils

# 线程安全阻塞队列

## 概述

#### 简介

线程安全阻塞队列SafeBlockQueue类，提供阻塞和非阻塞版的入队入队和出队接口，并提供可最追踪任务完成状态的的SafeBlockQueueTracking类。

`#include <safe_block_queue.h>`
## 涉及功能

### 接口说明

### OHOS::SafeBlockQueue

| 返回值 | 名称 |
| ------------ | ------------------------------------------------------------ |
| | **SafeBlockQueue**(int capacity) 构造函数 |
| | virtual **~SafeBlockQueue**() 析构函数 |
| void | virtual **Push**(T const& elem) 入队操作(阻塞版) |
| bool | virtual **PushNoWait**(T const& elem) 入队操作(非阻塞版) |
| T | **Pop**() 出队操作(阻塞版) |
| bool | **PopNotWait**(T& outtask) 出队操作(非阻塞版) |
| unsigned int | **Size**() 获取队列容量 |
| bool | **IsEmpty**() 队列判空 |
| bool | **IsFull**() 队列判满 |

### OHOS::SafeBlockQueueTracking
#### class SafeBlockQueueTracking : public SafeBlockQueue

| 返回值 | 名称 |
| -------- | ------------------------------------------------------------ |
| explicit | **SafeBlockQueueTracking**(int capacity) 构造函数 |
| | virtual **~SafeBlockQueueTracking**() 析构函数 |
| void | virtual **Push**(T const& elem) 入队操作(阻塞版) |
| bool | virtual **PushNoWait**(T const& elem) 入队操作(非阻塞版) |
| bool | **OneTaskDone**() 一个任务完成时的响应函数 |
| void | **Join**() 等待未完成队列 |
| int | **GetUnfinishTaskNum**() 获取未完成任务数 |

## 使用示例

1. 示例代码(伪代码)

- SafeBlockQueue的示例代码

```c++
#include <thread>
#include <functional>
#include <iostream>
#include "../include/safe_block_queue.h"

using namespace OHOS;
using namespace std;

constexpr int SIZE = 10;

class ProductsLine
{
public:
    ProductsLine(int maxSize) : que(maxSize) {}

void Produce()
 {
 for (int i = 0; i < SIZE + 1; i++) {
 que.Push(i);
 cout << "Add " << i << " to the line" << endl;
 }
 }

void Consume()
 {
 for (int i = 0; i < SIZE + 1; i++) {
 int out = que.Pop();
 cout << "Get " << out << " from the line" << endl;
 }
 }

int remains()
    {
        return que.Size();
    }

private:
 SafeBlockQueue<int> que;
};

int main()
{
    ProductsLine line(SIZE);

thread producer(bind(&ProductsLine::Produce, ref(line)));
    this_thread::sleep_for(chrono::milliseconds(1));

thread consumer(bind(&ProductsLine::Consume, ref(line)));
    this_thread::sleep_for(chrono::milliseconds(1));

producer.join();
    consumer.join();

if (line.remains()==0) {
 cout << line.remains() << " elements remains in the queue. Synchronizing success." <<endl;
 }
}
```

- SafeBlockQueueTracking的示例代码

```c++
#include <thread>
#include <functional>
#include <iostream>
#include "../include/safe_block_queue.h"

using namespace OHOS;
using namespace std;

constexpr int SIZE = 10;

class ProductsLine
{
public:
    ProductsLine(int maxSize) : que(maxSize) {}

void Produce()
 {
 for (int i = 0; i < SIZE + 1; i++) {
 que.Push(i);
 cout << "Add " << i << " to the line" << endl;
 }
 }

void Consume()
 {
 for (int i = 0; i < SIZE + 1; i++) {
 int out = que.Pop();
 cout << "Get " << out << " from the line" << endl;
 que.OneTaskDone();
 }
 }

void Join()
    {
        que.Join();
    }

int UnfinishTaskNum()
    {
        return que.GetUnfinishTaskNum();
    }

private:
 SafeBlockQueueTracking<int> que;
};

int main()
{
    ProductsLine line(SIZE);

thread producer(bind(&ProductsLine::Produce, ref(line)));
    this_thread::sleep_for(chrono::milliseconds(1));

thread consumer(bind(&ProductsLine::Consume, ref(line)));
    this_thread::sleep_for(chrono::milliseconds(1));

line.Join();

producer.join();
    consumer.join();

if (line.UnfinishTaskNum()==0) {
 cout << line.UnfinishTaskNum() << " elements remains in the queue. Synchronizing success." <<endl;
 }
}
```

2. 测试用例编译运行方法

- 测试用例代码参见base/test/unittest/common/utils_safe_block_queue_test.cpp 和 base/test/unittest/common/utils_safe_block_queue_tracking.cpp

- 使用开发者自测试框架，使用方法参见：[开发自测试执行框架-测试用例执行](https://gitee.com/openharmony/testfwk_developer_test#%E6%B5%8B%E8%AF%95%E7%94%A8%E4%BE%8B%E6%89%A7%E8%A1%8C)

- 使用以下具体命令以运行`safe_block_queue.h`对应测试用例
```bash
run -t UT -tp utils -ts UtilsSafeBlockQueueTest

# or

run -t UT -tp utils -ts UtilsSafeBlockQueueTrackingTest

```

## 常见问题

OpenHarmony/commonlibrary_c_utils
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