android中输入系统之内核到InputManagerService过程（源码）

愿每一份努力都不会被辜负-陈

文章目录

总体流程
事件的本质
Linux-Posix函数(关键函数用到)
从内核到IMS过程

总体流程

在Android中，Touch事件的分发分服务端和应用端。在服务端由WindowManagerService（借助InputManagerService）负责采集和分发的，在应用端则
是由ViewRootlmpl（内部有一个mView变量指向View树的根，负责控制View树的Ul绘制和事件消息的分发）负责分发的。当输入设备可用时，比如触屏，Linux内核会在/dev/input中创建对应的设备节点，输入事件所产生的原始信息会被Linux内核中的输入子系统采集，原始信息由Kernel Space的驱动层一直传递到User Space的设备节点。IMS所做的工作就是监听/dev/input下的所有的设备节点，当设备节点有数据时会将数据进行加工处理并找到合适的Window，将输入事件派发给它。

总体来说分为以下三个流程：事件采集，事件中转以及事件分发。

在这里插入图片描述

事件的本质

事件的本质其实就是一个个文件，事件产生后由Linux系统将数据保存到dev/input文件夹下。

我们可以通过命令来获取输入事件的信息：

adb shell getevent
adb shell input event 4
adb shell getevent -t -I

1
2
3
4

Linux-Posix函数(关键函数用到)

ePoll

被公认为Linux2.6下性能最好的多路l/O就绪通知方法。

epoll只有epoll_create,epoll_ctl,epoll_wait 3个系统调用。

epoll create：当创建好epoll句柄后，它就是会占用一个fd值，在linux下如果查看/proc/进程id/fd/，是能够看到这个fd的，所以在使用完epoll后，必须调用close()关闭，否则可能导致fd被耗尽(无限的创建文件夹同样会导致fd被耗尽)。
epoll _ctl：epol的事件注册函数，它不同于select（是在监听事件时告诉内核要监听什么类型的事件，而是在这里先注册要监听的事件类型。
epoll wait：收集在epoll监控的事件中已经发送的事件。参数events是分配好的epoll event结构体数组，epoll将会把发生的事件赋值到levents数组中(events不可以是空指针，内核只负责把数据复制到这个events数组中，不会去帮助我们在用户态中分配内存）。maxevents告之内核这个events有多大，这个maxevents的值不能大于创建epoll create（时的size，参数timeout是超时时间（毫秒，0会立即返回，-1将不确定，也有说法说是永久阻塞）。如果函数调用成功，返回对应/O上已准备好的文件描述符数目，如返回0表示已超时

具体参考：https://blog.csdn.net/xiajun07061225/article/details/9250579
iNotify

它是一个内核用于通知用户空间程序文件系统变化的机制

int fd = inotify init ():每一个inotify实例对应一个独立的排序的队列

inotify add watch:fd是 inotify init0返回的文件描述符,path是被监视的目标的路径名（即文件名或目录名）,mask是事件掩码,在头文件linux/inotify.h中定义了每一位代表的事件。可以使用同样的方式来修改事件掩码，即改变希望被通知的inotify 事件。Wd是watch描述符。

具体用法参考：https://blog.csdn.net/breakout_alex/article/details/89028868
socketpair

socketpairO函数用于创建一对无名的、相互连接的套接子。

具体使用参考：https://blog.csdn.net/weixin_40039738/article/details/81095013
fd

linux中，每一个进程在内核中，都对应有一个“打开文件”数组，存放指向文件对象的指针，而fd是这个数组的下标。
我们对文件进行操作时，系统调用，将fd传入内核，内核通过fd找到文件，对文件进行操作。
既然是数组下标，fd的类型为int，<0为非法值，>=0为合法值。在ilinux中，一个进程默认可以打开的文件数为1024个，fd的范围为0~1023。可以通
过设置，改变最大值。
在linux中，值为0、1、2的fd，分别代表标准输入、标准输出、标准错误输出。

从内核到IMS过程

源码流程

在这里插入图片描述

EventHub

INotify

INotify是Linux提供的一种文件系统变化通知机制，什么叫文件系统变化？创建，删除，读写通通叫做变化，使用如下代码就可以将某个目录加入到INotify中。
```
int inotifyFd = inotify init();
int wd =inotify_add_watch(inotifyFd,"/dev/input", IN_CREATE|IN_DELETE):
1
2
```
上述两行代码就将”/dev/input”加入到了INotify中，这样，对于外部输入设备的插拔就可以很好的被检测到了。可不幸的是，INotify发现文件系统变化后不
会主动告诉别人，它需要主动通过reado函数读取inotifyFd描述符来获取具体变化信息。也就是说，你插入了鼠标，INotify马上就知道了这个信息，并且将
信息更新到了inotifyFd描述符对应的对象当中

Eventhub

EventHub 通过读取/dev/input/下的相关文件来判断是否有新事件，并通知InputReader。

Epoll可以用来监听多个描述符的可读写inotifyFd状态，什么意思呢？比如说上面说到了外部输入设备插拔可以被INotify检测到，并且将相信信息写入到inotifyFd对用的对象中，但是我没法知道INotify什么时候捕获到了这些信息。而Epoll可以监听inotifyFd对应的对象内容是否有变化，一旦有变化马上能进行处理，平常大部分时间没监听到变化时睡大觉（其实Android中的Handler中的消息队列用到了epoll机制）。

epoll wait大部分时间处于阻塞状态（这点和socket等待连接很相似），一旦/dev/input/evento节点有变化（即产生了输入事件），epoll wait会执行完毕

//frameworks/native/services/inputflinger/EventHub.cpp
EventHub::EventHub(void) :
        mBuiltInKeyboardId(NO_BUILT_IN_KEYBOARD), mNextDeviceId(1), mControllerNumbers(),
        mOpeningDevices(0), mClosingDevices(0),
        mNeedToSendFinishedDeviceScan(false),
        mNeedToReopenDevices(false), mNeedToScanDevices(true),
        mPendingEventCount(0), mPendingEventIndex(0), mPendingINotify(false) {
    acquire_wake_lock(PARTIAL_WAKE_LOCK, WAKE_LOCK_ID);

     //创建epoll列表
    mEpollFd = epoll_create(EPOLL_SIZE_HINT);
    LOG_ALWAYS_FATAL_IF(mEpollFd < 0, "Could not create epoll instance.  errno=%d", errno);

     //初始化盘符并且监听。
    mINotifyFd = inotify_init();
    int result = inotify_add_watch(mINotifyFd, DEVICE_PATH, IN_DELETE | IN_CREATE);
    LOG_ALWAYS_FATAL_IF(result < 0, "Could not register INotify for %s.  errno=%d",
            DEVICE_PATH, errno);

    struct epoll_event eventItem;
    memset(&eventItem, 0, sizeof(eventItem));
    eventItem.events = EPOLLIN;
    eventItem.data.u32 = EPOLL_ID_INOTIFY;
     //epoll监听mINotifyFd。
    result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mINotifyFd, &eventItem);
    LOG_ALWAYS_FATAL_IF(result != 0, "Could not add INotify to epoll instance.  errno=%d", errno);

    int wakeFds[2];
    result = pipe(wakeFds);
    LOG_ALWAYS_FATAL_IF(result != 0, "Could not create wake pipe.  errno=%d", errno);

    mWakeReadPipeFd = wakeFds[0];
    mWakeWritePipeFd = wakeFds[1];

    result = fcntl(mWakeReadPipeFd, F_SETFL, O_NONBLOCK);
    LOG_ALWAYS_FATAL_IF(result != 0, "Could not make wake read pipe non-blocking.  errno=%d",
            errno);

    result = fcntl(mWakeWritePipeFd, F_SETFL, O_NONBLOCK);
    LOG_ALWAYS_FATAL_IF(result != 0, "Could not make wake write pipe non-blocking.  errno=%d",
            errno);

    eventItem.data.u32 = EPOLL_ID_WAKE;
    result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mWakeReadPipeFd, &eventItem);
    LOG_ALWAYS_FATAL_IF(result != 0, "Could not add wake read pipe to epoll instance.  errno=%d",
            errno);

    int major, minor;
    getLinuxRelease(&major, &minor);
    // EPOLLWAKEUP was introduced in kernel 3.5
    mUsingEpollWakeup = major > 3 || (major == 3 && minor >= 5);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52

IMS概述

InputReaderThread

InputReader会不断的循环读取EventHub中的原始输入事件。
InputDispatcherThread

InputDispatcher中保存了WMS中的所有的Window信息（WMS会将窗口的信息实时的更新到InputDispatcher中），这样InputDispatcher就可以将输入事
件派发给合适的Window

整体流程源码分析

由SystemServer启动一个IMS进程进程，然后进行各个对象的初始化

SystemServer开启其他服务（这个在之前的博客有详细介绍）

//com/android/server/SystemServer.java 
private void startOtherServices() {
      ......
        traceBeginAndSlog("StartInputManagerService");
        inputManager = new InputManagerService(context);
        traceEnd();
    
    //将inputManager与WindowManagerService关联
       wm = WindowManagerService.main(context, inputManager,
                    mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,
                    !mFirstBoot, mOnlyCore, new PhoneWindowManager());
    //注册wms服务
            ServiceManager.addService(Context.WINDOW_SERVICE, wm, /* allowIsolated= */ false,
                    DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PROTO);
    //注册ims服务
            ServiceManager.addService(Context.INPUT_SERVICE, inputManager,
                    /* allowIsolated= */ false, DUMP_FLAG_PRIORITY_CRITICAL);
      ......
  }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

InputManagerService的构造方法

    public InputManagerService(Context context) {
        this.mContext = context;
        this.mHandler = new InputManagerHandler(DisplayThread.get().getLooper());

        mUseDevInputEventForAudioJack =
                context.getResources().getBoolean(R.bool.config_useDevInputEventForAudioJack);
        Slog.i(TAG, "Initializing input manager, mUseDevInputEventForAudioJack="
                + mUseDevInputEventForAudioJack);
        //调用到jni的初始化方法。
        mPtr = nativeInit(this, mContext, mHandler.getLooper().getQueue());

        String doubleTouchGestureEnablePath = context.getResources().getString(
                R.string.config_doubleTouchGestureEnableFile);
        mDoubleTouchGestureEnableFile = TextUtils.isEmpty(doubleTouchGestureEnablePath) ? null :
            new File(doubleTouchGestureEnablePath);

        LocalServices.addService(InputManagerInternal.class, new LocalService());
    }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

同步会在native层进行初始化，开启一个InputManager对象,开启两个线程,一个Reader线程用来读取触摸信号,一个Dispatcher用来转发信息,EventHub负责采集底层信号。

通过jni调用到nativeInit方法。

//frameworks/base/services/core/jni/com_android_server_input_InputManagerService
   
static jlong nativeInit(JNIEnv* env, jclass /* clazz */,
        jobject serviceObj, jobject contextObj, jobject messageQueueObj) {
    sp<MessageQueue> messageQueue = android_os_MessageQueue_getMessageQueue(env, messageQueueObj);
    if (messageQueue == NULL) {
        jniThrowRuntimeException(env, "MessageQueue is not initialized.");
        return 0;
    }

    //初始化InputManager
    NativeInputManager* im = new NativeInputManager(contextObj, serviceObj,
            messageQueue->getLooper());
    im->incStrong(0);
    return reinterpret_cast<jlong>(im);
} 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

创建NativeInputManager对象

///frameworks/base/services/core/jni/com_android_server_input_InputManagerService.cpp
NativeInputManager::NativeInputManager(jobject contextObj,
        jobject serviceObj, const sp& looper) :
        mLooper(looper), mInteractive(true) {
    JNIEnv* env = jniEnv();

    mContextObj = env->NewGlobalRef(contextObj);
    mServiceObj = env->NewGlobalRef(serviceObj);

    {
        AutoMutex _l(mLock);
        mLocked.systemUiVisibility = ASYSTEM_UI_VISIBILITY_STATUS_BAR_VISIBLE;
        mLocked.pointerSpeed = 0;
        mLocked.pointerGesturesEnabled = true;
        mLocked.showTouches = false;
        mLocked.pointerCapture = false;
    }
    mInteractive = true;

     //注意此处创建了EventHub
    sp eventHub = new EventHub();
    //并把EventHub作为参数传入到InputManager中
    mInputManager = new InputManager(eventHub, this, this);
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

InputManager构造方法

/frameworks/native/services/inputflinger/InputManager.cpp
InputManager::InputManager(
        const sp& eventHub,
        const sp& readerPolicy,
        const sp& dispatcherPolicy) {
    //创建InputDispatcher对象
    mDispatcher = new InputDispatcher(dispatcherPolicy);
    //创建InputReader对象，InputReader在创建之初就与InputDispatcher产生了紧密的关联，后面会使用nQueuedListener->flush()通知事件。

    mReader = new InputReader(eventHub, readerPolicy, mDispatcher);
    //初始化
    initialize();
}
1
2
3
4
5
6
7
8
9
10
11
12
13

initialize()初始化

///frameworks/native/services/inputflinger/InputManager.cpp
void InputManager::initialize() {
    //创建绣程“InputReader”
    mReaderThread = new InputReaderThread(mReader);
    //创建线程”InputDispatcher“
    mDispatcherThread = new InputDispatcherThread(mDispatcher);
}
1
2
3
4
5
6
7

InputReader构造方法

//frameworks/native/services/inputflinger/InputReader.cpp
InputReader::InputReader(const sp<EventHubInterface>& eventHub,
        const sp<InputReaderPolicyInterface>& policy,
        const sp<InputListenerInterface>& listener) :
        mContext(this), mEventHub(eventHub), mPolicy(policy),
        mGlobalMetaState(0), mGeneration(1),
        mDisableVirtualKeysTimeout(LLONG_MIN), mNextTimeout(LLONG_MAX),
        mConfigurationChangesToRefresh(0) {
    //创建Listener回调，这个后面会调用nQueuedListener->flush()，记住这个listener是一个InputDispatcher
    mQueuedListener = new QueuedInputListener(listener);

    { // acquire lock
        AutoMutex _l(mLock);

        refreshConfigurationLocked(0);
        updateGlobalMetaStateLocked();
    } // release lock
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

InputDispatcher构造方法

//frameworks/native/services/inputflinger/InputDispatcher.cpp
InputDispatcher::InputDispatcher(const sp& policy) :
    mPolicy(policy),
    mPendingEvent(NULL), mLastDropReason(DROP_REASON_NOT_DROPPED),
    mAppSwitchSawKeyDown(false), mAppSwitchDueTime(LONG_LONG_MAX),
    mNextUnblockedEvent(NULL),
    mDispatchEnabled(false), mDispatchFrozen(false), mInputFilterEnabled(false),
    mInputTargetWaitCause(INPUT_TARGET_WAIT_CAUSE_NONE) {
    mLooper = new Looper(false);

    mKeyRepeatState.lastKeyEntry = NULL;

    policy->getDispatcherConfiguration(&mConfig);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14

通过IMS.start启动上面两个线程流程

inputManager.start()

//com/android/server/SystemServer.java
traceBeginAndSlog("StartInputManager");
            inputManager.setWindowManagerCallbacks(wm.getInputMonitor());
            inputManager.start();
            traceEnd();
1
2
3
4
5

InputManagerService.start

//com/android/server/input/InputManagerService.java 
public void start() {
        Slog.i(TAG, "Starting input manager");
      //jni 开启inputmanager
        nativeStart(mPtr);

        // Add ourself to the Watchdog monitors.
        Watchdog.getInstance().addMonitor(this);

        registerPointerSpeedSettingObserver();
        registerShowTouchesSettingObserver();
        registerAccessibilityLargePointerSettingObserver();

        mContext.registerReceiver(new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                updatePointerSpeedFromSettings();
                updateShowTouchesFromSettings();
                updateAccessibilityLargePointerFromSettings();
            }
        }, new IntentFilter(Intent.ACTION_USER_SWITCHED), null, mHandler);

        updatePointerSpeedFromSettings();
        updateShowTouchesFromSettings();
        updateAccessibilityLargePointerFromSettings();
    }

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

nativeStart()

///frameworks/base/services/core/jni/com_android_server_input_InputManagerService.cpp
static void nativeStart(JNIEnv* env, jclass /* clazz */, jlong ptr) {
    NativeInputManager* im = reinterpret_cast(ptr);

    status_t result = im->getInputManager()->start();
    if (result) {
        jniThrowRuntimeException(env, "Input manager could not be started.");
    }
}
1
2
3
4
5
6
7
8
9

///frameworks/base/services/core/jni/com_android_server_input_InputManagerService.cpp
status_t InputManager::start() {
    status_t result = mDispatcherThread->run("InputDispatcher", PRIORITY_URGENT_DISPLAY);
    if (result) {
        ALOGE("Could not start InputDispatcher thread due to error %d.", result);
        return result;
    }

    result = mReaderThread->run("InputReader", PRIORITY_URGENT_DISPLAY);
    if (result) {
        ALOGE("Could not start InputReader thread due to error %d.", result);

        mDispatcherThread->requestExit();
        return result;
    }

    return OK;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

InputRerader线程处理过程

InputRender线程运行。

///frameworks/native/services/inputflinger/InputReader.cpp
bool InputReaderThread::threadLoop() {
    mReader->loopOnce();
    return true;
}
1
2
3
4
5

处理事件

///frameworks/native/services/inputflinger/InputReader.cpp
void InputReader::loopOnce() {
    int32_t oldGeneration;
    int32_t timeoutMillis;
    bool inputDevicesChanged = false;
    Vector inputDevices;
    { // acquire lock
        AutoMutex _l(mLock);

        oldGeneration = mGeneration;
        timeoutMillis = -1;

        uint32_t changes = mConfigurationChangesToRefresh;
        if (changes) {
            mConfigurationChangesToRefresh = 0;
            timeoutMillis = 0;
            refreshConfigurationLocked(changes);
        } else if (mNextTimeout != LLONG_MAX) {
            nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
            timeoutMillis = toMillisecondTimeoutDelay(now, mNextTimeout);
        }
    } // release lock

	//内部有一个epoll_wait()  挂起
	//唤醒由linux驱动去更改dev/input下的文件造成  inotify+epoll,从Eventhub中读取事件，这里注意因为之前将的EventHub.getEvent中有epoll wait进行阻塞，若FD发生改变则执行后面代码
    //通过EventHub的getEvents函数获取事件信息，并存放到mEventBuffer中。

    size_t count = mEventHub->getEvents(timeoutMillis, mEventBuffer, EVENT_BUFFER_SIZE);

    { // acquire lock
        AutoMutex _l(mLock);
        mReaderIsAliveCondition.broadcast();

        if (count) {
			//处理事件信息，如果有事件信息，则进行加工处理。
            processEventsLocked(mEventBuffer, count);
        }

        if (mNextTimeout != LLONG_MAX) {
            nsecs_t now = systemTime(SYSTEM_TIME_MONOTONIC);
            if (now >= mNextTimeout) {
#if DEBUG_RAW_EVENTS
                ALOGD("Timeout expired, latency=%0.3fms", (now - mNextTimeout) * 0.000001f);
#endif
                mNextTimeout = LLONG_MAX;
                timeoutExpiredLocked(now);
            }
        }

        if (oldGeneration != mGeneration) {
            inputDevicesChanged = true;
            getInputDevicesLocked(inputDevices);
        }
    } // release lock

    // Send out a message that the describes the changed input devices.
    if (inputDevicesChanged) {
        mPolicy->notifyInputDevicesChanged(inputDevices);
    }

    // Flush queued events out to the listener.
    // This must happen outside of the lock because the listener could potentially call
    // back into the InputReader's methods, such as getScanCodeState, or become blocked
    // on another thread similarly waiting to acquire the InputReader lock thereby
    // resulting in a deadlock.  This situation is actually quite plausible because the
    // listener is actually the input dispatcher, which calls into the window manager,
    // which occasionally calls into the input reader.
    mQueuedListener->flush();
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69

处理事件信息:processEventsLocked

///frameworks/native/services/inputflinger/InputReader.cpp
void InputReader::processEventsLocked(const RawEvent* rawEvents, size_t count) {
    //遍历所有事件
    for (const RawEvent* rawEvent = rawEvents; count;) {
        int32_t type = rawEvent->type;
        size_t batchSize = 1;
        //事件类型分为原始输入事件和设备事件，这里时对原始输入事件的处理。
        if (type < EventHubInterface::FIRST_SYNTHETIC_EVENT) {
            int32_t deviceId = rawEvent->deviceId;
            while (batchSize < count) {
                if (rawEvent[batchSize].type >= EventHubInterface::FIRST_SYNTHETIC_EVENT
                        || rawEvent[batchSize].deviceId != deviceId) {
                    break;
                }
                batchSize += 1;
            }
#if DEBUG_RAW_EVENTS
            ALOGD("BatchSize: %zu Count: %zu", batchSize, count);
#endif
            //手动注意，继续调用。，处理deviceId所对应的设备的原始输入事件。
            processEventsForDeviceLocked(deviceId, rawEvent, batchSize);
        } else {
            //对设备事件进行处理。
            switch (rawEvent->type) {
            case EventHubInterface::DEVICE_ADDED:
                addDeviceLocked(rawEvent->when, rawEvent->deviceId);
                break;
            case EventHubInterface::DEVICE_REMOVED:
                removeDeviceLocked(rawEvent->when, rawEvent->deviceId);
                break;
            case EventHubInterface::FINISHED_DEVICE_SCAN:
                handleConfigurationChangedLocked(rawEvent->when);
                break;
            default:
                ALOG_ASSERT(false); // can't happen
                break;
            }
        }
        count -= batchSize;
        rawEvent += batchSize;
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

继续调用processEventsForDeviceLocked：

///frameworks/native/services/inputflinger/InputReader.cpp
void InputReader::processEventsForDeviceLocked(int32_t deviceId,
        const RawEvent* rawEvents, size_t count) {
    //从mDevices中获取对应的deviceIndex
    ssize_t deviceIndex = mDevices.indexOfKey(deviceId);
    if (deviceIndex < 0) {
        ALOGW("Discarding event for unknown deviceId %d.", deviceId);
        return;
    }

    //查找设备
    InputDevice* device = mDevices.valueAt(deviceIndex);
    if (device->isIgnored()) {
        //ALOGD("Discarding event for ignored deviceId %d.", deviceId);
        return;
    }

    device->process(rawEvents, count);
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

调用inputDevice.process()

///frameworks/native/services/inputflinger/InputReader.cpp
void InputDevice::process(const RawEvent* rawEvents, size_t count) {
    // Process all of the events in order for each mapper.
    // We cannot simply ask each mapper to process them in bulk because mappers may
    // have side-effects that must be interleaved.  For example, joystick movement events and
    // gamepad button presses are handled by different mappers but they should be dispatched
    // in the order received.
    size_t numMappers = mMappers.size();
    //遍历处理该InputDevice的所有事件
    for (const RawEvent* rawEvent = rawEvents; count != 0; rawEvent++) {
#if DEBUG_RAW_EVENTS
        ALOGD("Input event: device=%d type=0x%04x code=0x%04x value=0x%08x when=%" PRId64,
                rawEvent->deviceId, rawEvent->type, rawEvent->code, rawEvent->value,
                rawEvent->when);
#endif

        //mDropUntilNextSync默认值为false，如果设备的输入事件的缓冲区溢出，这个值为true
        if (mDropUntilNextSync) {
            if (rawEvent->type == EV_SYN && rawEvent->code == SYN_REPORT) {
                mDropUntilNextSync = false;
#if DEBUG_RAW_EVENTS
                ALOGD("Recovered from input event buffer overrun.");
#endif
            } else {
#if DEBUG_RAW_EVENTS
                ALOGD("Dropped input event while waiting for next input sync.");
#endif
            }
        } else if (rawEvent->type == EV_SYN && rawEvent->code == SYN_DROPPED) {
            ALOGI("Detected input event buffer overrun for device %s.", getName().string());
            mDropUntilNextSync = true;
            reset(rawEvent->when);
        } else {
            for (size_t i = 0; i < numMappers; i++) {
                InputMapper* mapper = mMappers[i];
                mapper->process(rawEvent);
            }
        }
        --count;
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42

交给对应的设备处理 mapper->process(rawEvent)，这里需要注意，InputMapper有很多的子类，我们要找触摸事件的相关处理就是找到TouchlnputMapper

///frameworks/native/services/inputflinger/InputReader.cpp
void TouchInputMapper::process(const RawEvent* rawEvent) {
    mCursorButtonAccumulator.process(rawEvent);
    mCursorScrollAccumulator.process(rawEvent);
    mTouchButtonAccumulator.process(rawEvent);

    if (rawEvent->type == EV_SYN && rawEvent->code == SYN_REPORT) {
        sync(rawEvent->when);
    }
}
1
2
3
4
5
6
7
8
9
10

继续sync

///frameworks/native/services/inputflinger/InputReader.cpp
void TouchInputMapper::sync(nsecs_t when) {
    const RawState* last = mRawStatesPending.isEmpty() ?
            &mCurrentRawState : &mRawStatesPending.top();

    // Push a new state.
    mRawStatesPending.push();
    RawState* next = &mRawStatesPending.editTop();
    next->clear();
    next->when = when;

    // Sync button state.
    next->buttonState = mTouchButtonAccumulator.getButtonState()
            | mCursorButtonAccumulator.getButtonState();

    // Sync scroll
    next->rawVScroll = mCursorScrollAccumulator.getRelativeVWheel();
    next->rawHScroll = mCursorScrollAccumulator.getRelativeHWheel();
    mCursorScrollAccumulator.finishSync();

    // Sync touch
    syncTouch(when, next);

    // Assign pointer ids.
    if (!mHavePointerIds) {
        assignPointerIds(last, next);
    }

#if DEBUG_RAW_EVENTS
    ALOGD("syncTouch: pointerCount %d -> %d, touching ids 0x%08x -> 0x%08x, "
            "hovering ids 0x%08x -> 0x%08x",
            last->rawPointerData.pointerCount,
            next->rawPointerData.pointerCount,
            last->rawPointerData.touchingIdBits.value,
            next->rawPointerData.touchingIdBits.value,
            last->rawPointerData.hoveringIdBits.value,
            next->rawPointerData.hoveringIdBits.value);
#endif

    processRawTouches(false /*timeout*/);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41

processRawTouches（最终的目的是找到数据的最终去向）

///frameworks/native/services/inputflinger/InputReader.cpp
void TouchInputMapper::processRawTouches(bool timeout) {
    if (mDeviceMode == DEVICE_MODE_DISABLED) {
        // Drop all input if the device is disabled.
        mCurrentRawState.clear();
        mRawStatesPending.clear();
        return;
    }

    // Drain any pending touch states. The invariant here is that the mCurrentRawState is always
    // valid and must go through the full cook and dispatch cycle. This ensures that anything
    // touching the current state will only observe the events that have been dispatched to the
    // rest of the pipeline.
    const size_t N = mRawStatesPending.size();
    size_t count;
    for(count = 0; count < N; count++) {
        const RawState& next = mRawStatesPending[count];

        // A failure to assign the stylus id means that we're waiting on stylus data
        // and so should defer the rest of the pipeline.
        if (assignExternalStylusId(next, timeout)) {
            break;
        }

        // All ready to go.
        clearStylusDataPendingFlags();
        mCurrentRawState.copyFrom(next);
        if (mCurrentRawState.when < mLastRawState.when) {
            mCurrentRawState.when = mLastRawState.when;
        }
        cookAndDispatch(mCurrentRawState.when);
    }
    if (count != 0) {
        mRawStatesPending.removeItemsAt(0, count);
    }

    if (mExternalStylusDataPending) {
        if (timeout) {
            nsecs_t when = mExternalStylusFusionTimeout - STYLUS_DATA_LATENCY;
            clearStylusDataPendingFlags();
            mCurrentRawState.copyFrom(mLastRawState);
#if DEBUG_STYLUS_FUSION
            ALOGD("Timeout expired, synthesizing event with new stylus data");
#endif
            //手动注意
            cookAndDispatch(when);
        } else if (mExternalStylusFusionTimeout == LLONG_MAX) {
            mExternalStylusFusionTimeout = mExternalStylusState.when + TOUCH_DATA_TIMEOUT;
            getContext()->requestTimeoutAtTime(mExternalStylusFusionTimeout);
        }
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52

cookAndDispatch

///frameworks/native/services/inputflinger/InputReader.cpp
void TouchInputMapper::cookAndDispatch(nsecs_t when) {
    // Always start with a clean state.
    mCurrentCookedState.clear();

    // Apply stylus buttons to current raw state.
    applyExternalStylusButtonState(when);

    // Handle policy on initial down or hover events.
    bool initialDown = mLastRawState.rawPointerData.pointerCount == 0
            && mCurrentRawState.rawPointerData.pointerCount != 0;

    uint32_t policyFlags = 0;
    bool buttonsPressed = mCurrentRawState.buttonState & ~mLastRawState.buttonState;
    if (initialDown || buttonsPressed) {
        // If this is a touch screen, hide the pointer on an initial down.
        if (mDeviceMode == DEVICE_MODE_DIRECT) {
            getContext()->fadePointer();
        }

        if (mParameters.wake) {
            policyFlags |= POLICY_FLAG_WAKE;
        }
    }

    // Consume raw off-screen touches before cooking pointer data.
    // If touches are consumed, subsequent code will not receive any pointer data.
    if (consumeRawTouches(when, policyFlags)) {
        mCurrentRawState.rawPointerData.clear();
    }

    // Cook pointer data.  This call populates the mCurrentCookedState.cookedPointerData structure
    // with cooked pointer data that has the same ids and indices as the raw data.
    // The following code can use either the raw or cooked data, as needed.
    cookPointerData();

    // Apply stylus pressure to current cooked state.
    applyExternalStylusTouchState(when);

    // Synthesize key down from raw buttons if needed.
    synthesizeButtonKeys(getContext(), AKEY_EVENT_ACTION_DOWN, when, getDeviceId(), mSource,
            policyFlags, mLastCookedState.buttonState, mCurrentCookedState.buttonState);

    // Dispatch the touches either directly or by translation through a pointer on screen.
    if (mDeviceMode == DEVICE_MODE_POINTER) {
        for (BitSet32 idBits(mCurrentRawState.rawPointerData.touchingIdBits);
                !idBits.isEmpty(); ) {
            uint32_t id = idBits.clearFirstMarkedBit();
            const RawPointerData::Pointer& pointer =
                    mCurrentRawState.rawPointerData.pointerForId(id);
            if (pointer.toolType == AMOTION_EVENT_TOOL_TYPE_STYLUS
                    || pointer.toolType == AMOTION_EVENT_TOOL_TYPE_ERASER) {
                mCurrentCookedState.stylusIdBits.markBit(id);
            } else if (pointer.toolType == AMOTION_EVENT_TOOL_TYPE_FINGER
                    || pointer.toolType == AMOTION_EVENT_TOOL_TYPE_UNKNOWN) {
                mCurrentCookedState.fingerIdBits.markBit(id);
            } else if (pointer.toolType == AMOTION_EVENT_TOOL_TYPE_MOUSE) {
                mCurrentCookedState.mouseIdBits.markBit(id);
            }
        }
        for (BitSet32 idBits(mCurrentRawState.rawPointerData.hoveringIdBits);
                !idBits.isEmpty(); ) {
            uint32_t id = idBits.clearFirstMarkedBit();
            const RawPointerData::Pointer& pointer =
                    mCurrentRawState.rawPointerData.pointerForId(id);
            if (pointer.toolType == AMOTION_EVENT_TOOL_TYPE_STYLUS
                    || pointer.toolType == AMOTION_EVENT_TOOL_TYPE_ERASER) {
                mCurrentCookedState.stylusIdBits.markBit(id);
            }
        }

        // Stylus takes precedence over all tools, then mouse, then finger.
        PointerUsage pointerUsage = mPointerUsage;
        if (!mCurrentCookedState.stylusIdBits.isEmpty()) {
            mCurrentCookedState.mouseIdBits.clear();
            mCurrentCookedState.fingerIdBits.clear();
            pointerUsage = POINTER_USAGE_STYLUS;
        } else if (!mCurrentCookedState.mouseIdBits.isEmpty()) {
            mCurrentCookedState.fingerIdBits.clear();
            pointerUsage = POINTER_USAGE_MOUSE;
        } else if (!mCurrentCookedState.fingerIdBits.isEmpty() ||
                isPointerDown(mCurrentRawState.buttonState)) {
            pointerUsage = POINTER_USAGE_GESTURES;
        }

        dispatchPointerUsage(when, policyFlags, pointerUsage);
    } else {
        if (mDeviceMode == DEVICE_MODE_DIRECT
                && mConfig.showTouches && mPointerController != NULL) {
            mPointerController->setPresentation(PointerControllerInterface::PRESENTATION_SPOT);
            mPointerController->fade(PointerControllerInterface::TRANSITION_GRADUAL);

            mPointerController->setButtonState(mCurrentRawState.buttonState);
            mPointerController->setSpots(mCurrentCookedState.cookedPointerData.pointerCoords,
                    mCurrentCookedState.cookedPointerData.idToIndex,
                    mCurrentCookedState.cookedPointerData.touchingIdBits);
        }

        if (!mCurrentMotionAborted) {
            dispatchButtonRelease(when, policyFlags);
            dispatchHoverExit(when, policyFlags);
            //手动注意，分发消息
            dispatchTouches(when, policyFlags);
            dispatchHoverEnterAndMove(when, policyFlags);
            dispatchButtonPress(when, policyFlags);
        }

        if (mCurrentCookedState.cookedPointerData.pointerCount == 0) {
            mCurrentMotionAborted = false;
        }
    }

    // Synthesize key up from raw buttons if needed.
    synthesizeButtonKeys(getContext(), AKEY_EVENT_ACTION_UP, when, getDeviceId(), mSource,
            policyFlags, mLastCookedState.buttonState, mCurrentCookedState.buttonState);

    // Clear some transient state.
    mCurrentRawState.rawVScroll = 0;
    mCurrentRawState.rawHScroll = 0;

    // Copy current touch to last touch in preparation for the next cycle.
    mLastRawState.copyFrom(mCurrentRawState);
    mLastCookedState.copyFrom(mCurrentCookedState);
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125

dispatchTouches

///frameworks/native/services/inputflinger/InputReader.cpp
void TouchInputMapper::dispatchTouches(nsecs_t when, uint32_t policyFlags) {
    BitSet32 currentIdBits = mCurrentCookedState.cookedPointerData.touchingIdBits;
    BitSet32 lastIdBits = mLastCookedState.cookedPointerData.touchingIdBits;
    int32_t metaState = getContext()->getGlobalMetaState();
    int32_t buttonState = mCurrentCookedState.buttonState;

    if (currentIdBits == lastIdBits) {
        if (!currentIdBits.isEmpty()) {
            // No pointer id changes so this is a move event.
            // The listener takes care of batching moves so we don't have to deal with that here.
            dispatchMotion(when, policyFlags, mSource,
                    AMOTION_EVENT_ACTION_MOVE, 0, 0, metaState, buttonState,
                    AMOTION_EVENT_EDGE_FLAG_NONE,
                    mCurrentCookedState.deviceTimestamp,
                    mCurrentCookedState.cookedPointerData.pointerProperties,
                    mCurrentCookedState.cookedPointerData.pointerCoords,
                    mCurrentCookedState.cookedPointerData.idToIndex,
                    currentIdBits, -1,
                    mOrientedXPrecision, mOrientedYPrecision, mDownTime);
        }
    } else {
        // There may be pointers going up and pointers going down and pointers moving
        // all at the same time.
        BitSet32 upIdBits(lastIdBits.value & ~currentIdBits.value);
        BitSet32 downIdBits(currentIdBits.value & ~lastIdBits.value);
        BitSet32 moveIdBits(lastIdBits.value & currentIdBits.value);
        BitSet32 dispatchedIdBits(lastIdBits.value);

        // Update last coordinates of pointers that have moved so that we observe the new
        // pointer positions at the same time as other pointers that have just gone up.
        bool moveNeeded = updateMovedPointers(
                mCurrentCookedState.cookedPointerData.pointerProperties,
                mCurrentCookedState.cookedPointerData.pointerCoords,
                mCurrentCookedState.cookedPointerData.idToIndex,
                mLastCookedState.cookedPointerData.pointerProperties,
                mLastCookedState.cookedPointerData.pointerCoords,
                mLastCookedState.cookedPointerData.idToIndex,
                moveIdBits);
        if (buttonState != mLastCookedState.buttonState) {
            moveNeeded = true;
        }

        // Dispatch pointer up events.
        while (!upIdBits.isEmpty()) {
            uint32_t upId = upIdBits.clearFirstMarkedBit();

            //手动注意。
            dispatchMotion(when, policyFlags, mSource,
                    AMOTION_EVENT_ACTION_POINTER_UP, 0, 0, metaState, buttonState, 0,
                    mCurrentCookedState.deviceTimestamp,
                    mLastCookedState.cookedPointerData.pointerProperties,
                    mLastCookedState.cookedPointerData.pointerCoords,
                    mLastCookedState.cookedPointerData.idToIndex,
                    dispatchedIdBits, upId, mOrientedXPrecision, mOrientedYPrecision, mDownTime);
            dispatchedIdBits.clearBit(upId);
        }

        // Dispatch move events if any of the remaining pointers moved from their old locations.
        // Although applications receive new locations as part of individual pointer up
        // events, they do not generally handle them except when presented in a move event.
        if (moveNeeded && !moveIdBits.isEmpty()) {
            ALOG_ASSERT(moveIdBits.value == dispatchedIdBits.value);
            dispatchMotion(when, policyFlags, mSource,
                    AMOTION_EVENT_ACTION_MOVE, 0, 0, metaState, buttonState, 0,
                    mCurrentCookedState.deviceTimestamp,
                    mCurrentCookedState.cookedPointerData.pointerProperties,
                    mCurrentCookedState.cookedPointerData.pointerCoords,
                    mCurrentCookedState.cookedPointerData.idToIndex,
                    dispatchedIdBits, -1, mOrientedXPrecision, mOrientedYPrecision, mDownTime);
        }

        // Dispatch pointer down events using the new pointer locations.
        while (!downIdBits.isEmpty()) {
            uint32_t downId = downIdBits.clearFirstMarkedBit();
            dispatchedIdBits.markBit(downId);

            if (dispatchedIdBits.count() == 1) {
                // First pointer is going down.  Set down time.
                mDownTime = when;
            }

            dispatchMotion(when, policyFlags, mSource,
                    AMOTION_EVENT_ACTION_POINTER_DOWN, 0, 0, metaState, buttonState, 0,
                    mCurrentCookedState.deviceTimestamp,
                    mCurrentCookedState.cookedPointerData.pointerProperties,
                    mCurrentCookedState.cookedPointerData.pointerCoords,
                    mCurrentCookedState.cookedPointerData.idToIndex,
                    dispatchedIdBits, downId, mOrientedXPrecision, mOrientedYPrecision, mDownTime);
        }
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92

dispatchMotion

///frameworks/native/services/inputflinger/InputReader.cpp
void TouchInputMapper::dispatchMotion(nsecs_t when, uint32_t policyFlags, uint32_t source,
        int32_t action, int32_t actionButton, int32_t flags,
        int32_t metaState, int32_t buttonState, int32_t edgeFlags, uint32_t deviceTimestamp,
        const PointerProperties* properties, const PointerCoords* coords,
        const uint32_t* idToIndex, BitSet32 idBits, int32_t changedId,
        float xPrecision, float yPrecision, nsecs_t downTime) {
    PointerCoords pointerCoords[MAX_POINTERS];
    PointerProperties pointerProperties[MAX_POINTERS];
    uint32_t pointerCount = 0;
    while (!idBits.isEmpty()) {
        uint32_t id = idBits.clearFirstMarkedBit();
        uint32_t index = idToIndex[id];
        pointerProperties[pointerCount].copyFrom(properties[index]);
        pointerCoords[pointerCount].copyFrom(coords[index]);

        if (changedId >= 0 && id == uint32_t(changedId)) {
            action |= pointerCount << AMOTION_EVENT_ACTION_POINTER_INDEX_SHIFT;
        }

        pointerCount += 1;
    }

    ALOG_ASSERT(pointerCount != 0);

    if (changedId >= 0 && pointerCount == 1) {
        // Replace initial down and final up action.
        // We can compare the action without masking off the changed pointer index
        // because we know the index is 0.
        if (action == AMOTION_EVENT_ACTION_POINTER_DOWN) {
            action = AMOTION_EVENT_ACTION_DOWN;
        } else if (action == AMOTION_EVENT_ACTION_POINTER_UP) {
            action = AMOTION_EVENT_ACTION_UP;
        } else {
            // Can't happen.
            ALOG_ASSERT(false);
        }
    }

    NotifyMotionArgs args(when, getDeviceId(), source, policyFlags,
            action, actionButton, flags, metaState, buttonState, edgeFlags,
            mViewport.displayId, deviceTimestamp, pointerCount, pointerProperties, pointerCoords,
            xPrecision, yPrecision, downTime);
    getListener()->notifyMotion(&args);
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46

getListener()->notifyMotion(&args);.当前这个getListener实际获取是mQueuedListener=new QueuedlnputListener(listener);实例

InputReader::InputReader(const sp& eventHub,
        const sp& policy,
        const sp& listener) :
        mContext(this), mEventHub(eventHub), mPolicy(policy),
        mGlobalMetaState(0), mGeneration(1),
        mDisableVirtualKeysTimeout(LLONG_MIN), mNextTimeout(LLONG_MAX),
        mConfigurationChangesToRefresh(0) {
    mQueuedListener = new QueuedInputListener(listener);

    { // acquire lock
        AutoMutex _l(mLock);

        refreshConfigurationLocked(0);
        updateGlobalMetaStateLocked();
    } // release lock
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

InputLintener.cpp.QueuedlnputListenernotifyMotion这里我们实际可以看到他就是往一个队列当中添加数据,实际上是我们将触摸相关的事件进行包装之后，将其加入到一个ArgsQueue队列，到此，我们已经将数据加入到参数队列中。

///frameworks/native/services/inputflinger/InputListener.cpp
void QueuedInputListener::notifyMotion(const NotifyMotionArgs* args) {
    mArgsQueue.push(new NotifyMotionArgs(*args));
}
1
2
3
4

这时我们在回到上面loopOnce（）方法中processEventsLocked调用之后，发现当前mQueueListener->flush的调用

    // Flush queued events out to the listener.
    // This must happen outside of the lock because the listener could potentially call
    // back into the InputReader's methods, such as getScanCodeState, or become blocked
    // on another thread similarly waiting to acquire the InputReader lock thereby
    // resulting in a deadlock.  This situation is actually quite plausible because the
    // listener is actually the input dispatcher, which calls into the window manager,
    // which occasionally calls into the input reader.
    mQueuedListener->flush();
1
2
3
4
5
6
7
8

flush（）

遍历整个mArgsQueue数组，在input架构中NotifyArgs的实现子类主要有以下几类

NotifyConfigurationChangedArgs
NotifyKeyArgs
NotifyMotionArgs 通知motion事件
NotifySwitchArgs
NotifvDeviceResetAras

///frameworks/native/services/inputflinger/InputListener.cpp
void QueuedInputListener::flush() {
    size_t count = mArgsQueue.size();
    for (size_t i = 0; i < count; i++) {
        NotifyArgs* args = mArgsQueue[i];
        args->notify(mInnerListener);
        delete args;
    }
    mArgsQueue.clear();
}

1
2
3
4
5
6
7
8
9
10
11

上面的listener根据溯源可以看到是lnputDispatcher，是调用InputDispatcher中的notifyMotion,这里就完成了向InputDispatcher的信息传递

void NotifyMotionArgs::notify(const sp& listener) const {
	//实际上就是在调用InputDispatcher.notifyMotion
    listener->notifyMotion(this);
}


InputReader::InputReader(const sp& eventHub,
        const sp& policy,
        const sp& listener) ://注意listener
        mContext(this), mEventHub(eventHub), mPolicy(policy),
        mGlobalMetaState(0), mGeneration(1),
        mDisableVirtualKeysTimeout(LLONG_MIN), mNextTimeout(LLONG_MAX),
        mConfigurationChangesToRefresh(0) {
    mQueuedListener = new QueuedInputListener(listener);//注意这个listener

    { // acquire lock
        AutoMutex _l(mLock);

        refreshConfigurationLocked(0);
        updateGlobalMetaStateLocked();
    } // release lock
}


InputManager::InputManager(
        const sp& eventHub,
        const sp& readerPolicy,
        const sp& dispatcherPolicy) {
    mDispatcher = new InputDispatcher(dispatcherPolicy);
    mReader = new InputReader(eventHub, readerPolicy, mDispatcher);//注意这个listener实际就是dispatcher
    initialize();
}


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34

10.执行notifyMotion中的唤醒操作InputDispatcher.cpp

///frameworks/native/services/inputflinger/InputDispatcher.cpp
void InputDispatcher::notifyMotion(const NotifyMotionArgs* args) {
#if DEBUG_INBOUND_EVENT_DETAILS
    ALOGD("notifyMotion - eventTime=%" PRId64 ", deviceId=%d, source=0x%x, policyFlags=0x%x, "
            "action=0x%x, actionButton=0x%x, flags=0x%x, metaState=0x%x, buttonState=0x%x,"
            "edgeFlags=0x%x, xPrecision=%f, yPrecision=%f, downTime=%" PRId64,
            args->eventTime, args->deviceId, args->source, args->policyFlags,
            args->action, args->actionButton, args->flags, args->metaState, args->buttonState,
            args->edgeFlags, args->xPrecision, args->yPrecision, args->downTime);
    for (uint32_t i = 0; i < args->pointerCount; i++) {
        ALOGD("  Pointer %d: id=%d, toolType=%d, "
                "x=%f, y=%f, pressure=%f, size=%f, "
                "touchMajor=%f, touchMinor=%f, toolMajor=%f, toolMinor=%f, "
                "orientation=%f",
                i, args->pointerProperties[i].id,
                args->pointerProperties[i].toolType,
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_X),
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_Y),
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_PRESSURE),
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_SIZE),
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_TOUCH_MAJOR),
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_TOUCH_MINOR),
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_TOOL_MAJOR),
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_TOOL_MINOR),
                args->pointerCoords[i].getAxisValue(AMOTION_EVENT_AXIS_ORIENTATION));
    }
#endif
    if (!validateMotionEvent(args->action, args->actionButton,
                args->pointerCount, args->pointerProperties)) {
        return;
    }

    uint32_t policyFlags = args->policyFlags;
    policyFlags |= POLICY_FLAG_TRUSTED;

    android::base::Timer t;
    mPolicy->interceptMotionBeforeQueueing(args->eventTime, /*byref*/ policyFlags);
    if (t.duration() > SLOW_INTERCEPTION_THRESHOLD) {
        ALOGW("Excessive delay in interceptMotionBeforeQueueing; took %s ms",
                std::to_string(t.duration().count()).c_str());
    }

    bool needWake;
    { // acquire lock
        mLock.lock();

        if (shouldSendMotionToInputFilterLocked(args)) {
            mLock.unlock();

            MotionEvent event;
            event.initialize(args->deviceId, args->source, args->action, args->actionButton,
                    args->flags, args->edgeFlags, args->metaState, args->buttonState,
                    0, 0, args->xPrecision, args->yPrecision,
                    args->downTime, args->eventTime,
                    args->pointerCount, args->pointerProperties, args->pointerCoords);

            policyFlags |= POLICY_FLAG_FILTERED;
            if (!mPolicy->filterInputEvent(&event, policyFlags)) {
                return; // event was consumed by the filter
            }

            mLock.lock();
        }

        // Just enqueue a new motion event.
        MotionEntry* newEntry = new MotionEntry(args->eventTime,
                args->deviceId, args->source, policyFlags,
                args->action, args->actionButton, args->flags,
                args->metaState, args->buttonState,
                args->edgeFlags, args->xPrecision, args->yPrecision, args->downTime,
                args->displayId,
                args->pointerCount, args->pointerProperties, args->pointerCoords, 0, 0);

        needWake = enqueueInboundEventLocked(newEntry);
        mLock.unlock();
    } // release lock

    if (needWake) {//注意这里唤醒looper。
        mLooper->wake();
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81

.InputDispatcher线程处理过程

InputDispatcher线程开启

///frameworks/native/services/inputflinger/InputDispatcher.cpp
bool InputDispatcherThread::threadLoop() {
    mDispatcher->dispatchOnce();
    return true;
}
1
2
3
4
5

dispatchOnce()轮询

pollOnce这里是等待被唤醒，进入epoll wait等待状态，当发生以下任一情况则退出等待状态：
callback：通过回调方法来唤醒；
timeout：到达nextWakeupTime时间，超时唤醒；
wake:主动调用Looper的wake0方法；

///frameworks/native/services/inputflinger/InputDispatcher.cpp
void InputDispatcher::dispatchOnce() {
    nsecs_t nextWakeupTime = LONG_LONG_MAX;
    { // acquire lock
        AutoMutex _l(mLock);
        mDispatcherIsAliveCondition.broadcast();

        // Run a dispatch loop if there are no pending commands.
        // The dispatch loop might enqueue commands to run afterwards.
        if (!haveCommandsLocked()) {
            dispatchOnceInnerLocked(&nextWakeupTime);
        }

        // Run all pending commands if there are any.
        // If any commands were run then force the next poll to wake up immediately.
        if (runCommandsLockedInterruptible()) {
            nextWakeupTime = LONG_LONG_MIN;
        }
    } // release lock

    // Wait for callback or timeout or wake.  (make sure we round up, not down)
    nsecs_t currentTime = now();
    int timeoutMillis = toMillisecondTimeoutDelay(currentTime, nextWakeupTime);
    mLooper->pollOnce(timeoutMillis);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

   
dispatchOnceInnerLocked
   
   ```c++
   ///frameworks/native/services/inputflinger/InputDispatcher.cpp
   void InputDispatcher::dispatchOnceInnerLocked(nsecs_t* nextWakeupTime) {
       nsecs_t currentTime = now();
   
       // Reset the key repeat timer whenever normal dispatch is suspended while the
       // device is in a non-interactive state.  This is to ensure that we abort a key
       // repeat if the device is just coming out of sleep.
       if (!mDispatchEnabled) {
           resetKeyRepeatLocked();
       }
   
       // If dispatching is frozen, do not process timeouts or try to deliver any new events.
       //如果InputDispatcher被冻结，则不进行派发操作。
       if (mDispatchFrozen) {
   #if DEBUG_FOCUS
           ALOGD("Dispatch frozen.  Waiting some more.");
   #endif
           return;
       }
   
       // Optimize latency of app switches.
       // Essentially we start a short timeout when an app switch key (HOME / ENDCALL) has
       // been pressed.  When it expires, we preempt dispatch and drop all other pending events.
       //如果isAppSwitchDue为true，则说明没有及时相应Home键操作。
       bool isAppSwitchDue = mAppSwitchDueTime <= currentTime;
       if (mAppSwitchDueTime < *nextWakeupTime) {
           *nextWakeupTime = mAppSwitchDueTime;
       }
   
       // Ready to start a new event.
       // If we don't already have a pending event, go grab one.
       //如果还没有待分发的事件，则在mInboundQueue中取出一个事件。
       if (! mPendingEvent) {
           //如果mInboundQueue为空，并且没有待分发的事件就return。
           if (mInboundQueue.isEmpty()) {
               if (isAppSwitchDue) {
                   // The inbound queue is empty so the app switch key we were waiting
                   // for will never arrive.  Stop waiting for it.
                   resetPendingAppSwitchLocked(false);
                   isAppSwitchDue = false;
               }
   
               // Synthesize a key repeat if appropriate.
               if (mKeyRepeatState.lastKeyEntry) {
                   if (currentTime >= mKeyRepeatState.nextRepeatTime) {
                       mPendingEvent = synthesizeKeyRepeatLocked(currentTime);
                   } else {
                       if (mKeyRepeatState.nextRepeatTime < *nextWakeupTime) {
                           *nextWakeupTime = mKeyRepeatState.nextRepeatTime;
                       }
                   }
               }
   
               // Nothing to do if there is no pending event.
               if (!mPendingEvent) {
                   return;
               }
           } else {
               // Inbound queue has at least one entry.
               //如果mInboundQueue不为空，则取队列头部的EventEntry赋值给mPendingEvent
               mPendingEvent = mInboundQueue.dequeueAtHead();
               traceInboundQueueLengthLocked();
           }
   
           // Poke user activity for this event.
           if (mPendingEvent->policyFlags & POLICY_FLAG_PASS_TO_USER) {
               pokeUserActivityLocked(mPendingEvent);
           }
   
           // Get ready to dispatch the event.
           resetANRTimeoutsLocked();
       }
   
       // Now we have an event to dispatch.
       // All events are eventually dequeued and processed this way, even if we intend to drop them.
       ALOG_ASSERT(mPendingEvent != NULL);
       bool done = false;
       DropReason dropReason = DROP_REASON_NOT_DROPPED;
       if (!(mPendingEvent->policyFlags & POLICY_FLAG_PASS_TO_USER)) {
           dropReason = DROP_REASON_POLICY;
       } else if (!mDispatchEnabled) {
           dropReason = DROP_REASON_DISABLED;
       }
   
       if (mNextUnblockedEvent == mPendingEvent) {
           mNextUnblockedEvent = NULL;
       }
   
       switch (mPendingEvent->type) {
       case EventEntry::TYPE_CONFIGURATION_CHANGED: {
           ConfigurationChangedEntry* typedEntry =
                   static_cast(mPendingEvent);
           done = dispatchConfigurationChangedLocked(currentTime, typedEntry);
           dropReason = DROP_REASON_NOT_DROPPED; // configuration changes are never dropped
           break;
       }
   
       case EventEntry::TYPE_DEVICE_RESET: {
           DeviceResetEntry* typedEntry =
                   static_cast(mPendingEvent);
           done = dispatchDeviceResetLocked(currentTime, typedEntry);
           dropReason = DROP_REASON_NOT_DROPPED; // device resets are never dropped
           break;
       }
   
       case EventEntry::TYPE_KEY: {
           KeyEntry* typedEntry = static_cast(mPendingEvent);
           if (isAppSwitchDue) {
               if (isAppSwitchKeyEventLocked(typedEntry)) {
                   resetPendingAppSwitchLocked(true);
                   isAppSwitchDue = false;
               } else if (dropReason == DROP_REASON_NOT_DROPPED) {
                   dropReason = DROP_REASON_APP_SWITCH;
               }
           }
           if (dropReason == DROP_REASON_NOT_DROPPED
                   && isStaleEventLocked(currentTime, typedEntry)) {
               dropReason = DROP_REASON_STALE;
           }
           if (dropReason == DROP_REASON_NOT_DROPPED && mNextUnblockedEvent) {
               dropReason = DROP_REASON_BLOCKED;
           }
           done = dispatchKeyLocked(currentTime, typedEntry, &dropReason, nextWakeupTime);
           break;
       }
   
       case EventEntry::TYPE_MOTION: {
           MotionEntry* typedEntry = static_cast(mPendingEvent);
           //没有及时响应窗口切换操作
           if (dropReason == DROP_REASON_NOT_DROPPED && isAppSwitchDue) {
               dropReason = DROP_REASON_APP_SWITCH;
           }
           //事件过期
           if (dropReason == DROP_REASON_NOT_DROPPED
                   && isStaleEventLocked(currentTime, typedEntry)) {
               dropReason = DROP_REASON_STALE;
           }
           //阻碍其他窗口获取事件
           if (dropReason == DROP_REASON_NOT_DROPPED && mNextUnblockedEvent) {
               dropReason = DROP_REASON_BLOCKED;
           }
           //手动注意
           done = dispatchMotionLocked(currentTime, typedEntry,
                   &dropReason, nextWakeupTime);
           break;
       }
   
       default:
           ALOG_ASSERT(false);
           break;
       }
   
       if (done) {
        if (dropReason != DROP_REASON_NOT_DROPPED) {
               dropInboundEventLocked(mPendingEvent, dropReason);
        }
           mLastDropReason = dropReason;
   
           //释放本次事件处理对象
        releasePendingEventLocked();
           //使InputDispatcher能够快速处理下一个分发事件。
           *nextWakeupTime = LONG_LONG_MIN;  // force next poll to wake up immediately
       }
   }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168

dispatchMotionLocked

这里两条线，
1.findTouchedWindowTargetLocked 负责找到要分发的Window
2.dispatchEventLocked 负责具体分发目标

///frameworks/native/services/inputflinger/InputDispatcher.cpp
bool InputDispatcher::dispatchMotionLocked(
        nsecs_t currentTime, MotionEntry* entry, DropReason* dropReason, nsecs_t* nextWakeupTime) {
    // Preprocessing.
    if (! entry->dispatchInProgress) {
        //标记当前已经进入分发流程
        entry->dispatchInProgress = true;

        logOutboundMotionDetailsLocked("dispatchMotion - ", entry);
    }

    //如果事件是需要丢弃的，则返回true，不会为该事件寻找合适的窗口
    // Clean up if dropping the event.
    if (*dropReason != DROP_REASON_NOT_DROPPED) {
        setInjectionResultLocked(entry, *dropReason == DROP_REASON_POLICY
                ? INPUT_EVENT_INJECTION_SUCCEEDED : INPUT_EVENT_INJECTION_FAILED);
        return true;
    }

    bool isPointerEvent = entry->source & AINPUT_SOURCE_CLASS_POINTER;

    // Identify targets.
    Vector inputTargets;

    bool conflictingPointerActions = false;
    int32_t injectionResult;
    if (isPointerEvent) {
        //处理触摸形式的事件，
        // Pointer event.  (eg. touchscreen)负责找到要分发的Window
        injectionResult = findTouchedWindowTargetsLocked(currentTime,
                entry, inputTargets, nextWakeupTime, &conflictingPointerActions);
    } else {
        //处理非触摸形式的事件 比如轨迹球。
        // Non touch event.  (eg. trackball)负责找到要分发的Window
        injectionResult = findFocusedWindowTargetsLocked(currentTime,
                entry, inputTargets, nextWakeupTime);
    }
    //输入事件被挂起，说明找到了窗口并且窗口无响应。
    if (injectionResult == INPUT_EVENT_INJECTION_PENDING) {
        return false;
    }

    setInjectionResultLocked(entry, injectionResult);
    //输入事件没有分发成功，说明没有找到合适的窗口。
    if (injectionResult != INPUT_EVENT_INJECTION_SUCCEEDED) {
        if (injectionResult != INPUT_EVENT_INJECTION_PERMISSION_DENIED) {
            CancelationOptions::Mode mode(isPointerEvent ?
                    CancelationOptions::CANCEL_POINTER_EVENTS :
                 CancelationOptions::CANCEL_NON_POINTER_EVENTS);
            CancelationOptions options(mode, "input event injection failed");
         synthesizeCancelationEventsForMonitorsLocked(options);
        }
     return true;
    }

    //将分发的目标添加到inputTargets列表中。
    addMonitoringTargetsLocked(inputTargets);

    // Dispatch the motion.
    if (conflictingPointerActions) {
        CancelationOptions options(CancelationOptions::CANCEL_POINTER_EVENTS,
                "conflicting pointer actions");
        synthesizeCancelationEventsForAllConnectionsLocked(options);
    }
    //将事件分发给inputTargets列表的目标。
    dispatchEventLocked(currentTime, entry, inputTargets);//负责具体分发目标
    return true;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68

我们先分析findTouchedWindowTargetLocked这条线。

这是一个很长的方法,省略一些无关的代码。大体是判断这个事件的类型，获取能够处理这个事件的forceground window,如果这个window不能够继续处理事件，就是说这个window的主线程被某些耗时操作占据，handleTargetsNotReadyLocked这个方法主要是判定当前的window是否发生ANR如果没有则处理下面的addWindowTargetLocked。

///frameworks/native/services/inputflinger/InputDispatcher.cpp
int32_t InputDispatcher::findTouchedWindowTargetsLocked(nsecs_t currentTime,
        const MotionEntry* entry, Vector& inputTargets, nsecs_t* nextWakeupTime,
        bool* outConflictingPointerActions) {

......
    //确保所有触摸过的前台窗口都为新的输入做好了准备
      for (size_t i = 0; i < mTempTouchState.windows.size(); i++) {
        const TouchedWindow& touchedWindow = mTempTouchState.windows[i];
        if (touchedWindow.targetFlags & InputTarget::FLAG_FOREGROUND) {
            // Check whether the window is ready for more input.
            //检查窗口是否准备好接收更多的输入。
            std::string reason = checkWindowReadyForMoreInputLocked(currentTime,
                    touchedWindow.windowHandle, entry, "touched");
            if (!reason.empty()) {
                //如果窗口没有准备好，则将原因赋值给injectionResult
                injectionResult = handleTargetsNotReadyLocked(currentTime, entry,
                        NULL, touchedWindow.windowHandle, nextWakeupTime, reason.c_str());
                goto Unresponsive;
            }
        }
    }  
    ......
        
        
          // Success!  Output targets.窗口检查成功
    injectionResult = INPUT_EVENT_INJECTION_SUCCEEDED;

    //遍历mTempTouchState中的窗口
    for (size_t i = 0; i < mTempTouchState.windows.size(); i++) {
        const TouchedWindow& touchedWindow = mTempTouchState.windows.itemAt(i);
       //为每个mTempTouchState中的窗口生成inputTargets
        addWindowTargetLocked(touchedWindow.windowHandle, touchedWindow.targetFlags,
                touchedWindow.pointerIds, inputTargets);
    }

    // Drop the outside or hover touch windows since we will not care about them
    // in the next iteration.
    //在下一次迭代中，删除外部窗口或悬停触摸窗口
    mTempTouchState.filterNonAsIsTouchWindows();
    ......
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43

addWindowTargetLocked这里主要的目的是将inputChannel添加至InputTarget中

///frameworks/native/services/inputflinger/InputDispatcher.cpp
void InputDispatcher::addWindowTargetLocked(const sp& windowHandle,
        int32_t targetFlags, BitSet32 pointerIds, Vector& inputTargets) {
    inputTargets.push();

    const InputWindowInfo* windowInfo = windowHandle->getInfo();
    InputTarget& target = inputTargets.editTop();
    target.inputChannel = windowInfo->inputChannel;
    target.flags = targetFlags;
    target.xOffset = - windowInfo->frameLeft;
    target.yOffset = - windowInfo->frameTop;
    target.scaleFactor = windowInfo->scaleFactor;
    target.pointerIds = pointerIds;
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

我们在看看另一条线dispatchEventLocked（向目标窗口发送事件）

///frameworks/native/services/inputflinger/InputDispatcher.cpp
void InputDispatcher::dispatchEventLocked(nsecs_t currentTime,
        EventEntry* eventEntry, const Vector& inputTargets) {
#if DEBUG_DISPATCH_CYCLE
    ALOGD("dispatchEventToCurrentInputTargets");
#endif

    ALOG_ASSERT(eventEntry->dispatchInProgress); // should already have been set to true

    pokeUserActivityLocked(eventEntry);

    //遍历inputTargets列表
    for (size_t i = 0; i < inputTargets.size(); i++) {
        const InputTarget& inputTarget = inputTargets.itemAt(i);

        //根据inputTarget内部的inputChannel来获取Connection的索引。
        ssize_t connectionIndex = getConnectionIndexLocked(inputTarget.inputChannel);
        if (connectionIndex >= 0) {
            //获取mConnectionsByFd容器中的Connection
            sp connection = mConnectionsByFd.valueAt(connectionIndex);
            //手动注意
            //根据inputTarget开始事件发送循环。
            prepareDispatchCycleLocked(currentTime, connection, eventEntry, &inputTarget);
        } else {
#if DEBUG_FOCUS
            ALOGD("Dropping event delivery to target with channel '%s' because it "
                    "is no longer registered with the input dispatcher.",
                    inputTarget.inputChannel->getName().c_str());
#endif
        }
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

prepareDispatchCycleLocked

///frameworks/native/services/inputflinger/InputDispatcher.cpp
void InputDispatcher::prepareDispatchCycleLocked(nsecs_t currentTime,
        const sp& connection, EventEntry* eventEntry, const InputTarget* inputTarget) {
#if DEBUG_DISPATCH_CYCLE
    ALOGD("channel '%s' ~ prepareDispatchCycle - flags=0x%08x, "
            "xOffset=%f, yOffset=%f, scaleFactor=%f, "
            "pointerIds=0x%x",
            connection->getInputChannelName().c_str(), inputTarget->flags,
            inputTarget->xOffset, inputTarget->yOffset,
            inputTarget->scaleFactor, inputTarget->pointerIds.value);
#endif

    // Skip this event if the connection status is not normal.
    // We don't want to enqueue additional outbound events if the connection is broken.
    if (connection->status != Connection::STATUS_NORMAL) {
#if DEBUG_DISPATCH_CYCLE
        ALOGD("channel '%s' ~ Dropping event because the channel status is %s",
                connection->getInputChannelName().c_str(), connection->getStatusLabel());
#endif
        return;
    }

    // Split a motion event if needed.
    if (inputTarget->flags & InputTarget::FLAG_SPLIT) {
        ALOG_ASSERT(eventEntry->type == EventEntry::TYPE_MOTION);

        MotionEntry* originalMotionEntry = static_cast(eventEntry);
        if (inputTarget->pointerIds.count() != originalMotionEntry->pointerCount) {
            MotionEntry* splitMotionEntry = splitMotionEvent(
                    originalMotionEntry, inputTarget->pointerIds);
            if (!splitMotionEntry) {
                return; // split event was dropped
            }
#if DEBUG_FOCUS
            ALOGD("channel '%s' ~ Split motion event.",
                    connection->getInputChannelName().c_str());
            logOutboundMotionDetailsLocked("  ", splitMotionEntry);
#endif
            //手动注意
            enqueueDispatchEntriesLocked(currentTime, connection,
                    splitMotionEntry, inputTarget);
            splitMotionEntry->release();
            return;
        }
    }

    // Not splitting.  Enqueue dispatch entries for the event as is.
    enqueueDispatchEntriesLocked(currentTime, connection, eventEntry, inputTarget);
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49

enqueueDispatchEntriesLocked

该方法主要功能：

根据dispatchMode来决定是否需要加入outboundQueue队列;
根据EventEntry,来生成DispatchEntry事件；
将dispatchEntry加入到connection的outbound队列.

执行到这里，其实等于又做了一次搬运的工作，将InputDispatcher中mlnboundQueue中的事件取出后，找到目标window后，封装dispatchEntry加入到connection的outbound队列.

///frameworks/native/services/inputflinger/InputDispatcher.cpp
void InputDispatcher::enqueueDispatchEntriesLocked(nsecs_t currentTime,
        const sp& connection, EventEntry* eventEntry, const InputTarget* inputTarget) {
    bool wasEmpty = connection->outboundQueue.isEmpty();

    //手动注意
    // Enqueue dispatch entries for the requested modes.
    enqueueDispatchEntryLocked(connection, eventEntry, inputTarget,
            InputTarget::FLAG_DISPATCH_AS_HOVER_EXIT);
    enqueueDispatchEntryLocked(connection, eventEntry, inputTarget,
            InputTarget::FLAG_DISPATCH_AS_OUTSIDE);
    enqueueDispatchEntryLocked(connection, eventEntry, inputTarget,
            InputTarget::FLAG_DISPATCH_AS_HOVER_ENTER);
    enqueueDispatchEntryLocked(connection, eventEntry, inputTarget,
            InputTarget::FLAG_DISPATCH_AS_IS);
    enqueueDispatchEntryLocked(connection, eventEntry, inputTarget,
            InputTarget::FLAG_DISPATCH_AS_SLIPPERY_EXIT);
    enqueueDispatchEntryLocked(connection, eventEntry, inputTarget,
            InputTarget::FLAG_DISPATCH_AS_SLIPPERY_ENTER);

    // If the outbound queue was previously empty, start the dispatch cycle going.
    if (wasEmpty && !connection->outboundQueue.isEmpty()) {
        startDispatchCycleLocked(currentTime, connection);
    }
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25

startDispatchCycleLocked

startDispatchCycleLocked的主要功能：从outboundQueue中取出事件,重新放入waitQueue队列

startDispatchCycleLocked触发时机：当起初connection.outboundQueue等于空，经enqueueDispatchEntryLocked处理后,outboundQueue不等于空。

///frameworks/native/services/inputflinger/InputDispatcher.cpp
void InputDispatcher::startDispatchCycleLocked(nsecs_t currentTime,
        const sp& connection) {
#if DEBUG_DISPATCH_CYCLE
    ALOGD("channel '%s' ~ startDispatchCycle",
            connection->getInputChannelName().c_str());
#endif

    while (connection->status == Connection::STATUS_NORMAL
            && !connection->outboundQueue.isEmpty()) {
        DispatchEntry* dispatchEntry = connection->outboundQueue.head;
        dispatchEntry->deliveryTime = currentTime;

        // Publish the event.
        status_t status;
        EventEntry* eventEntry = dispatchEntry->eventEntry;
        switch (eventEntry->type) {
        case EventEntry::TYPE_KEY: {
            KeyEntry* keyEntry = static_cast(eventEntry);

            // Publish the key event.
            status = connection->inputPublisher.publishKeyEvent(dispatchEntry->seq,
                    keyEntry->deviceId, keyEntry->source,
                    dispatchEntry->resolvedAction, dispatchEntry->resolvedFlags,
                    keyEntry->keyCode, keyEntry->scanCode,
                    keyEntry->metaState, keyEntry->repeatCount, keyEntry->downTime,
                    keyEntry->eventTime);
            break;
        }

        case EventEntry::TYPE_MOTION: {
            MotionEntry* motionEntry = static_cast(eventEntry);

            PointerCoords scaledCoords[MAX_POINTERS];
            const PointerCoords* usingCoords = motionEntry->pointerCoords;

            // Set the X and Y offset depending on the input source.
            float xOffset, yOffset;
            if ((motionEntry->source & AINPUT_SOURCE_CLASS_POINTER)
                    && !(dispatchEntry->targetFlags & InputTarget::FLAG_ZERO_COORDS)) {
                float scaleFactor = dispatchEntry->scaleFactor;
                xOffset = dispatchEntry->xOffset * scaleFactor;
                yOffset = dispatchEntry->yOffset * scaleFactor;
                if (scaleFactor != 1.0f) {
                    for (uint32_t i = 0; i < motionEntry->pointerCount; i++) {
                        scaledCoords[i] = motionEntry->pointerCoords[i];
                        scaledCoords[i].scale(scaleFactor);
                    }
                    usingCoords = scaledCoords;
                }
            } else {
                xOffset = 0.0f;
                yOffset = 0.0f;

                // We don't want the dispatch target to know.
                if (dispatchEntry->targetFlags & InputTarget::FLAG_ZERO_COORDS) {
                    for (uint32_t i = 0; i < motionEntry->pointerCount; i++) {
                        scaledCoords[i].clear();
                    }
                    usingCoords = scaledCoords;
                }
            }

            //手动注意
            // Publish the motion event.
            status = connection->inputPublisher.publishMotionEvent(dispatchEntry->seq,
                    motionEntry->deviceId, motionEntry->source, motionEntry->displayId,
                    dispatchEntry->resolvedAction, motionEntry->actionButton,
                    dispatchEntry->resolvedFlags, motionEntry->edgeFlags,
                    motionEntry->metaState, motionEntry->buttonState,
                    xOffset, yOffset, motionEntry->xPrecision, motionEntry->yPrecision,
                    motionEntry->downTime, motionEntry->eventTime,
                    motionEntry->pointerCount, motionEntry->pointerProperties,
                    usingCoords);
            break;
        }

        default:
            ALOG_ASSERT(false);
            return;
        }

        // Check the result.
        if (status) {
            if (status == WOULD_BLOCK) {
                if (connection->waitQueue.isEmpty()) {
                    ALOGE("channel '%s' ~ Could not publish event because the pipe is full. "
                            "This is unexpected because the wait queue is empty, so the pipe "
                            "should be empty and we shouldn't have any problems writing an "
                            "event to it, status=%d", connection->getInputChannelName().c_str(),
                            status);
                    abortBrokenDispatchCycleLocked(currentTime, connection, true /*notify*/);
                } else {
                    // Pipe is full and we are waiting for the app to finish process some events
                    // before sending more events to it.
#if DEBUG_DISPATCH_CYCLE
                    ALOGD("channel '%s' ~ Could not publish event because the pipe is full, "
                            "waiting for the application to catch up",
                            connection->getInputChannelName().c_str());
#endif
                    connection->inputPublisherBlocked = true;
                }
            } else {
                ALOGE("channel '%s' ~ Could not publish event due to an unexpected error, "
                        "status=%d", connection->getInputChannelName().c_str(), status);
                abortBrokenDispatchCycleLocked(currentTime, connection, true /*notify*/);
            }
            return;
        }

        // Re-enqueue the event on the wait queue.
        connection->outboundQueue.dequeue(dispatchEntry);
        traceOutboundQueueLengthLocked(connection);
        connection->waitQueue.enqueueAtTail(dispatchEntry);
        traceWaitQueueLengthLocked(connection);
    }
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118

至此调用了connection的inputPublisher的publishMotionEvent方法将事件分发消耗。

///frameworks/native/services/inputflinger/InputTransport.cpp
status_t InputPublisher::publishMotionEvent(
        uint32_t seq,
        int32_t deviceId,
        int32_t source,
        int32_t displayId,
        int32_t action,
        int32_t actionButton,
        int32_t flags,
        int32_t edgeFlags,
        int32_t metaState,
        int32_t buttonState,
        float xOffset,
        float yOffset,
        float xPrecision,
        float yPrecision,
        nsecs_t downTime,
        nsecs_t eventTime,
        uint32_t pointerCount,
        const PointerProperties* pointerProperties,
        const PointerCoords* pointerCoords) {
#if DEBUG_TRANSPORT_ACTIONS
    ALOGD("channel '%s' publisher ~ 
          publishMotionEvent: seq=%u, deviceId=%d, source=0x%x, "
            "action=0x%x, actionButton=0x%08x, flags=0x%x, edgeFlags=0x%x, "
            "metaState=0x%x, buttonState=0x%x, xOffset=%f, yOffset=%f, "
            "xPrecision=%f, yPrecision=%f, downTime=%" PRId64 ", eventTime=%" PRId64 ", "
            "pointerCount=%" PRIu32,
            mChannel->getName().c_str(), seq,
            deviceId, source, action, actionButton, flags, edgeFlags, metaState, buttonState,
            xOffset, yOffset, xPrecision, yPrecision, downTime, eventTime, pointerCount);
#endif

    if (!seq) {
        ALOGE("Attempted to publish a motion event with sequence number 0.");
        return BAD_VALUE;
    }

    if (pointerCount > MAX_POINTERS || pointerCount < 1) {
        ALOGE("channel '%s' publisher ~ Invalid number of pointers provided: %" PRIu32 ".",
                mChannel->getName().c_str(), pointerCount);
        return BAD_VALUE;
    }

    InputMessage msg;
    msg.header.type = InputMessage::TYPE_MOTION;
    msg.body.motion.seq = seq;
    msg.body.motion.deviceId = deviceId;
    msg.body.motion.source = source;
    msg.body.motion.displayId = displayId;
    msg.body.motion.action = action;
    msg.body.motion.actionButton = actionButton;
    msg.body.motion.flags = flags;
    msg.body.motion.edgeFlags = edgeFlags;
    msg.body.motion.metaState = metaState;
    msg.body.motion.buttonState = buttonState;
    msg.body.motion.xOffset = xOffset;
    msg.body.motion.yOffset = yOffset;
    msg.body.motion.xPrecision = xPrecision;
    msg.body.motion.yPrecision = yPrecision;
    msg.body.motion.downTime = downTime;
    msg.body.motion.eventTime = eventTime;
    msg.body.motion.pointerCount = pointerCount;
    for (uint32_t i = 0; i < pointerCount; i++) {
        msg.body.motion.pointers[i].properties.copyFrom(pointerProperties[i]);
        msg.body.motion.pointers[i].coords.copyFrom(pointerCoords[i]);
    }
    //最后将消息发送
    return mChannel->sendMessage(&msg);
}

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71

相关阅读:
Java中级编程大师班＜第一篇：初识数据结构与算法(1)＞
Tiktok抖音最新无人互动直播项目：猜成语V4版（带语音感谢用户送礼物功能）源代码解析
 河北2022中国农民丰收节国稻种芯：主会场活动在塔元庄举行
 Gartner 存储与数据保护技术 Hype Cycle 解读｜SmartX 趋势分享
 QT航空客运订票系统
 Linux关机命令、选项和原理详解
 Leetcode81. Search in Rotated Sorted Array II
MyBatis动态设置要连接的数据库地址，用户名，密码
 并发编程系列 - ReadWriteLock
2022年Vue.js面试题汇总及答案【建议收藏】
原文地址：https://blog.csdn.net/chendeshan330/article/details/126755928