基于AOP的代码插桩

场景一：统计自定义方法耗时及调用次数

方案：

通过Aspect.addBefore对自定义方法进行执行前插桩记录方法调用前时间、Aspect.addAfter对自定义方法进行执行后插桩记录执行后时间，以统计方法耗时及调用次数。

核心代码：

function addTimePrinter(targetClass: Object, methodName: string, isStatic: boolean) {
  let count: number = 0
  let t1 = 0;
  let t2 = 0;
  util.Aspect.addBefore(targetClass, methodName, isStatic, () => {
    t1 = new Date().getTime();
  })
  util.Aspect.addAfter(targetClass, methodName, isStatic, (instance: Object, ret: number) => {

    count+=1
    t2 = new Date().getTime();
    console.log(methodName+"方法耗时为t2 - t1 = " + (t2 - t1).toString());
    console.log(methodName+"方法调用次数为count = " + count);
    return ret;
  })
}

function doSomeWork(time: number) {
  let start = Date.now()
  while (Date.now()-start<time){
    continue
  }
  console.log('延时 '+time+"ms");
}

export class Test {
  delay1000() {
    doSomeWork(1000);  // 1000ms的任务
  }
  static delay2000() {
    doSomeWork(2000);  // 1000ms的任务
  }
}
addTimePrinter(Test,'delay1000',false)
addTimePrinter(Test,'delay2000',true)

场景二：应用间跳转--获取目标应用包名

方案：

在EntryAbility的onCreate方法中对UIAbilityContext类的startAbility方法进行插桩，以获取Want参数的bundleName属性。此场景addAfter、addBefore都可完成，本例通过addAfter实现。

核心代码：

由于UIAbilityContext是系统提供的类且没有导出，无法直接import，因此可以通过EntryAbility的context成员（该成员是从UIAbility继承而来）获取UIAbilityContext类对象，然后在onCreate方法中完成插桩操作。

import { BusinessError } from '@kit.BasicServicesKit';
import { GlobalThis} from '../utils/GlobalThis'
import util from '@ohos.util';

let context  = GlobalThis.getInstance().getContext("context")

export function Jump(){
  let want: Want = {
    bundleName: 'com.example.myapplication_taskpool_settime',
    abilityName: 'EntryAbility'
  };
  try {
    context?.startAbility(want, (err: BusinessError) => {
      if (err.code) {
        // 处理业务逻辑错误
        console.error(`testtag startAbility failed, code is ${err.code}, message is ${err.message}`);
        return;
      }
      // 执行正常业务
      console.info('testtag startAbility succeed');
    });
  } catch (err) {
    // 处理入参错误异常
    let code = (err as BusinessError).code;
    let message = (err as BusinessError).message;
    console.error(`testtag  startAbility failed, code is ${code}, message is ${message}`);
    console.error(`testtag  startAbility failed, code is ${code}, message is ${message}`);
  }
}

util.Aspect.addAfter(context?.constructor, "startAbility", false, (instance: Object, ret: Object, want: Want): void => {
    console.error("testtag 获取目标包名"+want?.bundleName);
  }
);

同理，可以采用相同的方法获取来源应用包名。例：对EntryAbility的onCreate方法进行插桩，当本应用被其他应用调用触发onCreate回调，以获取Want参数的bundleName属性。此场景addAfter、addBefore都可完成，本例通过addBefore实现。

//获取来源包名
util.Aspect.addBefore(EntryAbility, "onCreate", false, (instance: EntryAbility, want: Want): void => {
  let params = want.parameters as Record<string, Object>;
  console.error('testtag 获取来源包名'+params['ohos.aafwk.param.callerBundleName']);
});