ANR InputDispatching TimeOut超时判断

Posted 2022-12-10 xhBruce

ANR InputDispatching TimeOut超时判断

• InputDispatching超时判断
• • InputReader\\InputDispatcher初始化，及其线程启动
  • InputDispatching
  • • InputDispatcher::dispatchOnceInnerLocked()
    • InputDispatcher::checkWindowReadyForMoreInputLocked()
  • InputDispatching超时判断
  • ANR log输出
  • 感谢

InputDispatching超时判断

android-9.0.0_r8

InputReader\\InputDispatcher初始化，及其线程启动

JNI涉及java层和C/C++层，ANR超时判断在C/C++层

InputDispatching

Input事件超时主要是事件分发超时，从标题就有提示。
InputDispatcherThread是InputDispatcher的notifyMotion函数唤醒，执行InputDispatcherThread的threadLoop函数
dispatchOnceInnerLocked开始计时，handleTargetsNotReadyLocked里进行判断超时。

InputDispatcher::dispatchOnceInnerLocked()

在派发事件时，dispatchKeyLocked()和dispatchMotionLocked()， 需要找到当前的焦点窗口，焦点窗口才是最终接收事件的地方，找窗口的过程就会判断是否已经发生了ANR。

1、当前时间，ANR计时的起点

2、当分发被冻结，则不再处理超时和分发事件的工作

3、如果isAppSwitchDue为true，说明没有及时响应HOME键等操作，则抢占分发，丢弃其他所有即将要处理的事件。

4、mInboundQueue不为空,则取出头部的事件,放入mPendingEvent变量;并重置ANR时间

5、根据EventEntry的type类型分别处理，比如按键调用dispatchKeyLocked分发事件

6、执行完成(done)的处理。根据dropReason(默认DROP_REASON_NOT_DROPPED不处理)来决定是否丢失事件；releasePendingEventLocked 释放当前正在处理的事件(即mPendingEvent)； 强制立刻执行轮询LONG_LONG_MIN

InputDispatcher::checkWindowReadyForMoreInputLocked()

ANR输出相关原因

InputDispatching超时判断

int32_t InputDispatcher::handleTargetsNotReadyLocked(nsecs_t currentTime,
        const EventEntry* entry,
        const sp<InputApplicationHandle>& applicationHandle,
        const sp<InputWindowHandle>& windowHandle,
        nsecs_t* nextWakeupTime, const char* reason) 
    if (applicationHandle == NULL && windowHandle == NULL) 
        if (mInputTargetWaitCause != INPUT_TARGET_WAIT_CAUSE_SYSTEM_NOT_READY) 
#if DEBUG_FOCUS
            ALOGD("Waiting for system to become ready for input.  Reason: %s", reason);
#endif
            mInputTargetWaitCause = INPUT_TARGET_WAIT_CAUSE_SYSTEM_NOT_READY;
            mInputTargetWaitStartTime = currentTime;
            mInputTargetWaitTimeoutTime = LONG_LONG_MAX;
            mInputTargetWaitTimeoutExpired = false;
            mInputTargetWaitApplicationHandle.clear();
        
     else 
        if (mInputTargetWaitCause != INPUT_TARGET_WAIT_CAUSE_APPLICATION_NOT_READY) 
#if DEBUG_FOCUS
            ALOGD("Waiting for application to become ready for input: %s.  Reason: %s",
                    getApplicationWindowLabelLocked(applicationHandle, windowHandle).c_str(),
                    reason);
#endif
            nsecs_t timeout;
            if (windowHandle != NULL) 
                timeout = windowHandle->getDispatchingTimeout(DEFAULT_INPUT_DISPATCHING_TIMEOUT);
             else if (applicationHandle != NULL) 
                timeout = applicationHandle->getDispatchingTimeout(
                        DEFAULT_INPUT_DISPATCHING_TIMEOUT);
             else 
                timeout = DEFAULT_INPUT_DISPATCHING_TIMEOUT;
            

            mInputTargetWaitCause = INPUT_TARGET_WAIT_CAUSE_APPLICATION_NOT_READY;
            mInputTargetWaitStartTime = currentTime;
            mInputTargetWaitTimeoutTime = currentTime + timeout;
            mInputTargetWaitTimeoutExpired = false;
            mInputTargetWaitApplicationHandle.clear();

            if (windowHandle != NULL) 
                mInputTargetWaitApplicationHandle = windowHandle->inputApplicationHandle;
            
            if (mInputTargetWaitApplicationHandle == NULL && applicationHandle != NULL) 
                mInputTargetWaitApplicationHandle = applicationHandle;
            
        
    

    if (mInputTargetWaitTimeoutExpired) 
        return INPUT_EVENT_INJECTION_TIMED_OUT;
    

    if (currentTime >= mInputTargetWaitTimeoutTime) 
        onANRLocked(currentTime, applicationHandle, windowHandle,
                entry->eventTime, mInputTargetWaitStartTime, reason);

        // Force poll loop to wake up immediately on next iteration once we get the
        // ANR response back from the policy.
        *nextWakeupTime = LONG_LONG_MIN;
        return INPUT_EVENT_INJECTION_PENDING;
     else 
        // Force poll loop to wake up when timeout is due.
        if (mInputTargetWaitTimeoutTime < *nextWakeupTime) 
            *nextWakeupTime = mInputTargetWaitTimeoutTime;
        
        return INPUT_EVENT_INJECTION_PENDING;
    

currentTime >= mInputTargetWaitTimeoutTime超时判断，执行onANRLocked
1、currentTime是指执行dispatchOnceInnerLocked方法体的起点
2、mInputTargetWaitTimeoutTime = currentTime + timeout默认超时时间是五秒DEFAULT_INPUT_DISPATCHING_TIMEOUT

3、mInputTargetWaitCause等于INPUT_TARGET_WAIT_CAUSE_APPLICATION_NOT_READY(应用没有准备就绪)，而前面resetANRTimeoutsLocked()过程是唯一用于重置等待理由的地方。可见，ANR时间区间是从dispatchOnceInnerLocked方法体的起点，直到下次执行handleTargetsNotReadyLocked()方法的这段应用未准备就绪的时间段，该时间段是否超过5s来决定是否触发ANR。

ANR log输出

JNI层

java层

和ANR service TimeOut 超时判断、ANR Broadcast TimeOut 超时判断一样使用AppErrors.appNotResponding最终输出Log

感谢

ANR机制以及问题分析
Input系统—ANR原理分析
Input系统—InputDispatcher线程
Android输入系统（三）InputReader的加工类型和InputDispatcher的分发过程