92 lines
2.4 KiB
Markdown
92 lines
2.4 KiB
Markdown
# ReadWriteLock
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**命名空间**: `XCEngine::Threading`
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**类型**: `class`
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**头文件**: `XCEngine/Threading/ReadWriteLock.h`
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**描述**: 读写锁，允许多个读者或单个写者
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## 概述
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`ReadWriteLock` 实现了一个经典的读写锁。它允许多个线程同时持有读锁，但在有写锁时，所有读锁都必须释放，写锁为独占访问。这对于读操作远多于写操作的共享数据非常有效。
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### 设计目的
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- 提供比普通互斥锁更高的并发性能
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- 允许多个线程同时读取共享数据
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- 确保写入操作时的独占性访问
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- 防止写者饥饿（通过写者优先策略）
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### 使用场景
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- 读多写少的共享数据访问
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- 需要保护长时间读取的数据结构
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- 数据库、缓存、配置等共享资源访问
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## 公共方法
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| 方法 | 描述 |
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|------|------|
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| [`ReadWriteLock`](constructor.md) | 构造一个读写锁 |
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| [`~ReadWriteLock`](destructor.md) | 销毁读写锁 |
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| [`ReadLock`](readlock.md) | 获取读锁（支持多个并发读者） |
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| [`ReadUnlock`](readunlock.md) | 释放读锁 |
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| [`WriteLock`](writelock.md) | 获取写锁（独占，阻塞所有读者和写者） |
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| [`WriteUnlock`](writeunlock.md) | 释放写锁 |
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## 使用示例
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```cpp
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#include "XCEngine/Threading/ReadWriteLock.h"
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#include <thread>
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#include <vector>
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#include <iostream>
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#include <map>
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XCEngine::Threading::ReadWriteLock rwLock;
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std::map<std::string, int> sharedCache;
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// 读操作（多个线程可同时读）
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int ReadData(const std::string& key) {
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rwLock.ReadLock();
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int value = 0;
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auto it = sharedCache.find(key);
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if (it != sharedCache.end()) {
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value = it->second;
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}
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rwLock.ReadUnlock();
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return value;
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}
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// 写操作（独占）
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void WriteData(const std::string& key, int value) {
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rwLock.WriteLock();
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sharedCache[key] = value;
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rwLock.WriteUnlock();
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}
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int main() {
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std::vector<std::thread> threads;
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threads.emplace_back(WriteData, "score", 100);
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threads.emplace_back(ReadData, "score");
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threads.emplace_back(WriteData, "health", 200);
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threads.emplace_back(ReadData, "health");
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for (auto& t : threads) {
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t.join();
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}
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return 0;
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}
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```
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## 相关文档
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- [`ReadLock`](readlock.md) - 获取读锁
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- [`ReadUnlock`](readunlock.md) - 释放读锁
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- [`WriteLock`](writelock.md) - 获取写锁
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- [`WriteUnlock`](writeunlock.md) - 释放写锁
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