一.input 系統初始化
InputManagerService(java):
SystemService.run    --->    startOtherServices    ---->    new InputManagerService    ---->    NativeInit

(cpp)
new NativeInputManager: public virtual InputReaderPolicyInterface, public virtual InputDispatcherPolicyInterface, public virtual PointerControllerPolicyInterface 
    ---->
 
 new EventHub : public EventHubInterface
        ----> epoll && inotify 監測 /dev/input 下檔案的建立與刪除
        ----> 建立pipe並用epoll監聽其中的ReadPipe 

    ----> new InputManager(eventHub) : public InputManagerInterface
        ----> new InputDispatcher : public InputDispatcherInterface 
        ---->
 
 new InputReader : public InputReaderInterface 
            ----> new QueuedInputListener(InputDispatcher.InputListenerInterface)

        ----> initialize
            ----> new InputReaderThread(InputReader.InputReaderInterface)
            ----> new InputDispatcherThread(InputDispatcher.InputDispatcherInterface)

(java)
inputManager.setWindowManagerCallbacks(wm.getInputMonitor()) ---->
 
 mWindowManagerCallbacks = callbacks
inputManager.start() nativeStart

(cpp)
NativeInputManager->getInputManager()->start()
    ----> mDispatcherThread->run("InputDispatcher", PRIORITY_URGENT_DISPLAY) ----> threadLoop(){InputReaderInterface->loopOnce();return true;}
    ----> mReaderThread->run("InputReader", PRIORITY_URGENT_DISPLAY)         ----> threadLoop(){InputDispatcherInterface->dispatchOnce();return true;}

二.讀取input events
InputReaderInterface->loopOnce ----> EventHub->getEvents ----> scanDevicesLocked or readNotifyLocked ----> openDeviceLocked ----> new Device 
    ----> processEventsLocked ---> addDeviceLocked ----> createDeviceLocked(InputDevice) ----> new InputDevice ----> addaddMapper ----> mDevices.add
    or--> processEventsForDeviceLocked ----> device->process ----> InputDevice::process ----> mapper->process

        ----> MultiTouchInputMapper::process
            ----> TouchInputMapper::process(rawEvent)
                ----> mCursorButtonAccumulator.process(rawEvent);
                ----> mCursorScrollAccumulator.process(rawEvent);
                ----> mTouchButtonAccumulator.process(rawEvent)
                    ----> TouchInputMapper::sync ----> processRawTouches ----> cookAndDispatch ----> dispatchTouches ----> TouchInputMapper::dispatchMotion ----> getListener()->notifyMotion
                        ----> InputDispatcherInterface.notifyMotion 
                            ----> InputDispatcherPolicyInterface->interceptMotionBeforeQueueing
                            ----> mPolicy->filterInputEvent(&event, policyFlags) //可能會根據java中的policy過濾改event
                            ----> enqueueInboundEventLocked(newEntry) //判斷是否需要喚起dispatchOnce
            ----> mMultiTouchMotionAccumulator.process(rawEvent)

三.分發events
InputDispatcherInterface.dispatchOnce ----> dispatchOnceInnerLocked
    ----> mPendingEvent = mInboundQueue.dequeueAtHead() //取出event
    ----> pokeUserActivityLocked(mPendingEvent) //封裝成系統讀取的時間 呼叫mPolicy
    ----> dispatchMotionLocked 
        ----> findTouchedWindowTargetsLocked //得到要對應的UI視窗
        ----> dispatchEventLocked
            ----> connectionIndex = getConnectionIndexLocked(inputTarget.inputChannel)
            ----> connection = mConnectionsByFd.valueAt(connectionIndex)
            ----> prepareDispatchCycleLocked ----> enqueueDispatchEntriesLocked
                ----> startDispatchCycleLocked ----> status = connection->inputPublisher.publishMotionEvent