HarmonyOS 内存管理 ets、TS相关？

Question

GC文档：https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/gc-introduction-V5 只是粗略概述，是否有详细文档。

以下是代码参考：

interface RRIoTMessageListener {
  (message: any): void;
}

class MessageHandlerRegistry {
  private listeners: Map<string, Set<WeakRef<RRIoTMessageListener>>>;
  private finalizationRegistry: FinalizationRegistry<WeakRef<RRIoTMessageListener>>;

  constructor() {
    this.listeners = new Map<string, Set<WeakRef<RRIoTMessageListener>>>();
    this.finalizationRegistry = new FinalizationRegistry((weakRef) => {
      // 遍历所有 topic，移除已经被垃圾回收的 listener
      for (const [topic, listeners] of this.listeners.entries()) {
        listeners.delete(weakRef);
        if (listeners.size === 0) {
          this.listeners.delete(topic);
        }
      }
    });
  }

  registerMessageHandler(listener: RRIoTMessageListener, topic: string): void {
    const weakRef = new WeakRef(listener);
    if (!this.listeners.has(topic)) {
      this.listeners.set(topic, new Set<WeakRef<RRIoTMessageListener>>());
    }
    this.listeners.get(topic)!.add(weakRef);
    this.finalizationRegistry.register(listener, weakRef);
  }

  notifyListeners(topic: string, message: any): void {
    if (this.listeners.has(topic)) {
      const listeners = this.listeners.get(topic)!;
      for (const weakRef of listeners) {
        const listener = weakRef.deref();
        if (listener) {
          listener(message);
        } else {
          listeners.delete(weakRef); // 移除已被垃圾回收的 weakRef
        }
      }
      if (listeners.size === 0) {
        this.listeners.delete(topic);
      }
    }
  }
}

直接赋值为空

class SmartDevice {
  private deviceName: string;

  constructor(deviceName: string) {
    this.deviceName = deviceName;
  }

  onMessageReceived(message: any): void {
    console.log(`${this.deviceName} received: ${message}`);
  }
}
// 使用示例
const registry = new MessageHandlerRegistry();
const device1 = new SmartDevice('Device 1');
const device2 = new SmartDevice('Device 2');
// 注册 SmartDevice 实例
registry.registerMessageHandler(device1.onMessageReceived.bind(device1), 'topic1');
registry.registerMessageHandler(device2.onMessageReceived.bind(device2), 'topic1');
// 发送消息
registry.notifyListeners('topic1', 'Hello, World!');
// 输出：
// Device 1 received: Hello, World!
// Device 2 received: Hello, World!
// 模拟垃圾回收
device1 = null;
device2 = null;
// 假设垃圾回收已经发生
registry.notifyListeners('topic1', 'Hello again!');
// 不会有任何输出，因为 device1 和 device2 都已被销毁

const registry = new MessageHandlerRegistry();

{
  const device = new SmartDevice('Smart Device');
  const monitoringSystem = new MonitoringSystem('Monitoring System');
  // 注册观察者
  registry.registerMessageHandler(device);
  registry.registerMessageHandler(monitoringSystem);
  // 发送消息
  registry.notifyDpsMessage('topic1', 'Hello, World!', 1);
  registry.notifyDeviceOnlineMessage('device123', true);
  // 输出：
  // Smart Device received DPS message: Hello, World! on topic topic1 with QoS 1
  // Monitoring System monitoring DPS message: Hello, World! on topic topic1 with QoS 1
  // Smart Device detected device device123 is online
  // Monitoring System detected device device123 is online
}
// 由于device和monitoringSystem在块作用域结束后没有其他引用，将被垃圾回收
// 假设垃圾回收已经发生
registry.notifyDpsMessage('topic1', 'Hello again!', 1);
registry.notifyDeviceOnlineMessage('device123', false);
// 不会有任何输出，因为 device 和 monitoringSystem 都已被销毁

Answer 1

class对象不需要时就自动释放了，使用的是GC自动回收机制，不是引用机制。参考文档：https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/gc-introduction-V5