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js 实现同步锁

2026-03-16 04:41:21JavaScript

同步锁的实现方法

在JavaScript中实现同步锁可以通过多种方式，以下是几种常见的方法：

使用Promise和async/await

通过Promise和async/await可以模拟同步锁的行为。创建一个锁变量，并在需要同步的代码块中使用await等待锁释放。

let lock = Promise.resolve();

async function withLock(fn) {
  const oldLock = lock;
  let releaseLock;
  lock = new Promise(resolve => {
    releaseLock = resolve;
  });
  await oldLock;
  try {
    return await fn();
  } finally {
    releaseLock();
  }
}

// 使用示例
async function criticalSection() {
  await withLock(async () => {
    console.log('进入临界区');
    await new Promise(resolve => setTimeout(resolve, 1000));
    console.log('离开临界区');
  });
}

使用Mutex库

可以使用第三方库如async-mutex来实现更复杂的锁机制。安装后直接使用其提供的Mutex类。

npm install async-mutex

const { Mutex } = require('async-mutex');
const mutex = new Mutex();

async function criticalSection() {
  const release = await mutex.acquire();
  try {
    console.log('进入临界区');
    await new Promise(resolve => setTimeout(resolve, 1000));
    console.log('离开临界区');
  } finally {
    release();
  }
}

使用Atomics和SharedArrayBuffer

对于多线程环境（如Web Worker），可以使用Atomics和SharedArrayBuffer实现低级锁。

js 实现同步锁

const sharedBuffer = new SharedArrayBuffer(4);
const sharedArray = new Int32Array(sharedBuffer);
const LOCKED = 1;
const UNLOCKED = 0;

function acquireLock() {
  while (true) {
    if (Atomics.compareExchange(sharedArray, 0, UNLOCKED, LOCKED) === UNLOCKED) {
      return;
    }
    Atomics.wait(sharedArray, 0, LOCKED);
  }
}

function releaseLock() {
  if (Atomics.compareExchange(sharedArray, 0, LOCKED, UNLOCKED) !== LOCKED) {
    throw new Error('Lock was not acquired');
  }
  Atomics.notify(sharedArray, 0, 1);
}

// 使用示例
acquireLock();
console.log('进入临界区');
setTimeout(() => {
  console.log('离开临界区');
  releaseLock();
}, 1000);