深入理解QT并发机制

class WorkerThread : public QThread {
    void run() override {
        // 在这里执行耗时操作
        qDebug() << "Worker thread running";
    }
};

// 使用
WorkerThread *thread = new WorkerThread;
thread->start(); // 启动线程

class Worker : public QObject {
    Q_OBJECT
public slots:
    void doWork() {
        // 执行耗时任务
        emit resultReady(result);
    }
signals:
    void resultReady(const QString &result);
};

// 使用
QThread *thread = new QThread;
Worker *worker = new Worker;
worker->moveToThread(thread);

connect(thread, &QThread::started, worker, &Worker::doWork);
connect(worker, &Worker::resultReady, [](const QString &result){
    // 处理结果
});

thread->start();

// 并行映射
QList<int> list = {1, 2, 3, 4, 5};
QFuture<void> future = QtConcurrent::map(list, [](int &x){
    x *= 2;
});
future.waitForFinished(); // 等待完成

// 并行过滤
QFuture<int> filtered = QtConcurrent::filtered(list, [](int x){
    return x > 5;
});

// 并行归约
int sum = QtConcurrent::blockingReduced(list, [](int &result, int x){
    result += x;
});

class Task : public QRunnable {
    void run() override {
        // 执行任务
    }
};

// 使用
Task *task = new Task;
QThreadPool::globalInstance()->start(task);

QMutex mutex;
mutex.lock();
// 临界区代码
mutex.unlock();

// 或使用 QMutexLocker
QMutexLocker locker(&mutex);
// 临界区代码

QReadWriteLock lock;
lock.lockForRead();  // 多个读取
lock.lockForWrite(); // 单个写入

QSemaphore sem(5); // 5个资源
sem.acquire(3);    // 获取3个
sem.release(2);    // 释放2个

QWaitCondition condition;
QMutex mutex;

// 等待线程
mutex.lock();
condition.wait(&mutex);
mutex.unlock();

// 唤醒线程
condition.wakeOne(); // 或 wakeAll()

QMetaObject::invokeMethod(object, "methodName",
                         Qt::QueuedConnection,
                         Q_ARG(QString, "param"));

QFuture<int> future = QtConcurrent::run([](){
    return 42;
});

QFutureWatcher<int> *watcher = new QFutureWatcher<int>;
connect(watcher, &QFutureWatcher<int>::finished, [](){
    qDebug() << "Done";
});
watcher->setFuture(future);