Android Activity 启动拦截器（ActivityStartInterceptor）创建流程, 以及使用

代码基于 Android 11

ActivityTaskManagerService # initialize

    public void initialize(IntentFirewall intentFirewall, PendingIntentController intentController,
            Looper looper) {
        mActivityStartController = new ActivityStartController(this);
    }

ActivityStartController

创建 DefaultFactory 工厂类

    ActivityStartController(ActivityTaskManagerService service) {
        this(service, service.mStackSupervisor,
                new DefaultFactory(service, service.mStackSupervisor,
                    new ActivityStartInterceptor(service, service.mStackSupervisor)));
    }

    @VisibleForTesting
    ActivityStartController(ActivityTaskManagerService service, ActivityStackSupervisor supervisor,
            Factory factory) {
        mService = service;
        mSupervisor = supervisor;
        mHandler = new StartHandler(mService.mH.getLooper());
        mFactory = factory;
        mFactory.setController(this);
        mPendingRemoteAnimationRegistry = new PendingRemoteAnimationRegistry(service.mGlobalLock,
                service.mH);
    }

DefaultFactory 创建

DefaultFactory 用来生产 ActivityStarter

传递 ActivityStartInterceptor 拦截器给DefaultFactory

    DefaultFactory(ActivityTaskManagerService service,
            ActivityStackSupervisor supervisor, ActivityStartInterceptor interceptor) {
        mService = service;
        mSupervisor = supervisor;
        mInterceptor = interceptor;
    }

创建ActivityStarter

传递 ActivityStartInterceptor 拦截器给ActivityStarter

    public ActivityStarter obtain() {
        ActivityStarter starter = mStarterPool.acquire();

        if (starter == null) {
            starter = new ActivityStarter(mController, mService, mSupervisor, mInterceptor);
        }

        return starter;
    }

构造 ActivityStarter

ActivityStarter 获取拦截器：ActivityStartInterceptor

    ActivityStarter(ActivityStartController controller, ActivityTaskManagerService service,
            ActivityStackSupervisor supervisor, ActivityStartInterceptor interceptor) {
        mController = controller;
        mService = service;
        mRootWindowContainer = service.mRootWindowContainer;
        mSupervisor = supervisor;
        mInterceptor = interceptor;
        reset(true);
    }

ActivityStartInterceptor 拦截器的使用

int executeRequest(Request request) {
   mInterceptor.setStates(userId, realCallingPid, realCallingUid, startFlags, callingPackage,
           callingFeatureId);
   if (mInterceptor.intercept(intent, rInfo, aInfo, resolvedType, inTask, callingPid,
           callingUid, checkedOptions)) {
       // activity start was intercepted, e.g. because the target user is currently in quiet
       // mode (turn off work) or the target application is suspended
       intent = mInterceptor.mIntent;
       rInfo = mInterceptor.mRInfo;
       aInfo = mInterceptor.mAInfo;
       resolvedType = mInterceptor.mResolvedType;
       inTask = mInterceptor.mInTask;
       callingPid = mInterceptor.mCallingPid;
       callingUid = mInterceptor.mCallingUid;
       checkedOptions = mInterceptor.mActivityOptions;

       // The interception target shouldn't get any permission grants
       // intended for the original destination
       intentGrants = null;
   }
}