touchEventNative

static const char *WAKE_LOCK_ID = "KeyEvents";
static const char *DEVICE_PATH = "/dev/input";

private void startOtherServices() {
            inputManager = new InputManagerService(context);
  
            wm = WindowManagerService.main(context, inputManager,
                    mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,
                    !mFirstBoot, mOnlyCore, new PhoneWindowManager());
            ServiceManager.addService(Context.WINDOW_SERVICE, wm, /* allowIsolated= */ false,
                    DUMP_FLAG_PRIORITY_CRITICAL | DUMP_FLAG_PROTO);
            ServiceManager.addService(Context.INPUT_SERVICE, inputManager,
                    /* allowIsolated= */ false, DUMP_FLAG_PRIORITY_CRITICAL);
  
          ......
            inputManager.setWindowManagerCallbacks(wm.getInputMonitor());
            inputManager.start();
}

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

        mPtr = nativeInit(this, mContext, mHandler.getLooper().getQueue());
    }
}

    public void start() {
        Slog.i(TAG, "Starting input manager");
        nativeStart(mPtr);
    }

    public void registerInputChannel(InputChannel inputChannel,
            InputWindowHandle inputWindowHandle) {
        nativeRegisterInputChannel(mPtr, inputChannel, inputWindowHandle, false);
    }

static jlong nativeInit(JNIEnv* env, jclass /* clazz */,
        jobject serviceObj, jobject contextObj, jobject messageQueueObj) {
    sp<MessageQueue> messageQueue = android_os_MessageQueue_getMessageQueue(env, messageQueueObj);

    NativeInputManager* im = new NativeInputManager(contextObj, serviceObj,
            messageQueue->getLooper());
    im->incStrong(0);
    return reinterpret_cast<jlong>(im);
}

static void nativeStart(JNIEnv* env, jclass /* clazz */, jlong ptr) {
    NativeInputManager* im = reinterpret_cast<NativeInputManager*>(ptr);

    status_t result = im->getInputManager()->start();
}

static void nativeRegisterInputChannel(JNIEnv* env, jclass /* clazz */,
        jlong ptr, jobject inputChannelObj, jobject inputWindowHandleObj, jboolean monitor) {
    NativeInputManager* im = reinterpret_cast<NativeInputManager*>(ptr);
      status_t status = im->registerInputChannel(
            env, inputChannel, inputWindowHandle, monitor);
}

NativeInputManager::NativeInputManager(jobject contextObj,
        jobject serviceObj, const sp<Looper>& looper) :
        mLooper(looper), mInteractive(true) {
    sp<EventHub> eventHub = new EventHub();
    mInputManager = new InputManager(eventHub, this, this);
}

status_t NativeInputManager::registerInputChannel(JNIEnv* /* env */,
        const sp<InputChannel>& inputChannel,
        const sp<InputWindowHandle>& inputWindowHandle, bool monitor) {
    ATRACE_CALL();
    return mInputManager->getDispatcher()->registerInputChannel(
            inputChannel, inputWindowHandle, monitor);
}

InputManager::InputManager(
        const sp<EventHubInterface>& eventHub,
        const sp<InputReaderPolicyInterface>& readerPolicy,
        const sp<InputDispatcherPolicyInterface>& dispatcherPolicy) {
    mDispatcher = new InputDispatcher(dispatcherPolicy);
    mReader = new InputReader(eventHub, readerPolicy, mDispatcher);
    initialize();
}

void InputManager::initialize() {
    mReaderThread = new InputReaderThread(mReader);
    mDispatcherThread = new InputDispatcherThread(mDispatcher);
}

status_t InputManager::start() {
    status_t result = mDispatcherThread->run("InputDispatcher", PRIORITY_URGENT_DISPLAY);
    result = mReaderThread->run("InputReader", PRIORITY_URGENT_DISPLAY);
    return OK;
}

EventHub::EventHub(void) : {
     mEpollFd = epoll_create(EPOLL_SIZE_HINT);

    mINotifyFd = inotify_init();
    int result = inotify_add_watch(mINotifyFd, DEVICE_PATH, IN_DELETE | IN_CREATE);

    struct epoll_event eventItem;
    memset(&eventItem, 0, sizeof(eventItem));
    eventItem.events = EPOLLIN;
    eventItem.data.u32 = EPOLL_ID_INOTIFY;
    result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mINotifyFd, &eventItem);
    
    int wakeFds[2];
    result = pipe(wakeFds);

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

    result = fcntl(mWakeReadPipeFd, F_SETFL, O_NONBLOCK);
    result = fcntl(mWakeWritePipeFd, F_SETFL, O_NONBLOCK);

    eventItem.data.u32 = EPOLL_ID_WAKE;
    result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mWakeReadPipeFd, &eventItem);
}

size_t EventHub::getEvents(int timeoutMillis, RawEvent* buffer, size_t bufferSize) {
        for (;;) {
         // Grab the next input event.
        bool deviceChanged = false;
        while (mPendingEventIndex < mPendingEventCount) {
            const struct epoll_event& eventItem = mPendingEventItems[mPendingEventIndex++];
            if (eventItem.data.u32 == EPOLL_ID_INOTIFY) {
                if (eventItem.events & EPOLLIN) {
                    mPendingINotify = true;
                }
                continue;
            }
            ......
           if (mPendingINotify && mPendingEventIndex >= mPendingEventCount) {
            mPendingINotify = false;
            readNotifyLocked();
           }
        }
        int pollResult = epoll_wait(mEpollFd, mPendingEventItems, EPOLL_MAX_EVENTS, timeoutMillis);
        }

status_t EventHub::readNotifyLocked() {
    res = read(mINotifyFd, event_buf, sizeof(event_buf));
}

bool InputReaderThread::threadLoop() {
    mReader->loopOnce();
    return true;
}

InputReader::InputReader(const sp<EventHubInterface>& eventHub,
        const sp<InputReaderPolicyInterface>& policy,
        const sp<InputListenerInterface>& listener) :
        mContext(this), mEventHub(eventHub), mPolicy(policy), {
    mQueuedListener = new QueuedInputListener(listener);
 }

bool InputReaderThread::threadLoop() {
    mReader->loopOnce();
    return true;
}

void InputReader::loopOnce() {
  size_t count = mEventHub->getEvents(timeoutMillis, mEventBuffer, EVENT_BUFFER_SIZE);
        if (count) {
            processEventsLocked(mEventBuffer, count);
        }
    // 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();
}

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();
}

void NotifyMotionArgs::notify(const sp<InputListenerInterface>& listener) const {
    listener->notifyMotion(this);
}

bool InputDispatcherThread::threadLoop() {
    mDispatcher->dispatchOnce();
    return true;
}

void InputDispatcher::dispatchOnce() {
  
        // Run a dispatch loop if there are no pending commands.
        // The dispatch loop might enqueue commands to run afterwards.
        if (!haveCommandsLocked()) {
            dispatchOnceInnerLocked(&nextWakeupTime);
        }
  
    // 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);//registerInputChannel时通过Looper.wake()唤醒线程
}

void InputDispatcher::notifyMotion(const NotifyMotionArgs* args) { 
    if (needWake) {
        mLooper->wake();
    }
}

void InputDispatcher::dispatchOnceInnerLocked(nsecs_t* nextWakeupTime) {
    case EventEntry::TYPE_MOTION: {
        MotionEntry* typedEntry = static_cast<MotionEntry*>(mPendingEvent);
        if (dropReason == DROP_REASON_NOT_DROPPED && isAppSwitchDue) {
            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 = dispatchMotionLocked(currentTime, typedEntry,
                &dropReason, nextWakeupTime);
        break;
    }

bool InputDispatcher::dispatchMotionLocked(
        nsecs_t currentTime, MotionEntry* entry, DropReason* dropReason, nsecs_t* nextWakeupTime) {
    dispatchEventLocked(currentTime, entry, inputTargets);
    return true;
}

void InputDispatcher::dispatchEventLocked(nsecs_t currentTime,
        EventEntry* eventEntry, const Vector<InputTarget>& inputTargets) {
      for (size_t i = 0; i < inputTargets.size(); i++) {
        const InputTarget& inputTarget = inputTargets.itemAt(i);

        ssize_t connectionIndex = getConnectionIndexLocked(inputTarget.inputChannel);
        if (connectionIndex >= 0) {
            sp<Connection> connection = mConnectionsByFd.valueAt(connectionIndex);
            prepareDispatchCycleLocked(currentTime, connection, eventEntry, &inputTarget);
        } 
}

void InputDispatcher::prepareDispatchCycleLocked(nsecs_t currentTime,
        const sp<Connection>& connection, EventEntry* eventEntry, const InputTarget* inputTarget) {
                enqueueDispatchEntriesLocked(currentTime, connection, splitMotionEntry, inputTarget);
}

void InputDispatcher::enqueueDispatchEntriesLocked(nsecs_t currentTime,
        const sp<Connection>& connection, EventEntry* eventEntry, const InputTarget* inputTarget) {
    bool wasEmpty = connection->outboundQueue.isEmpty();
    ......

    // If the outbound queue was previously empty, start the dispatch cycle going.
    if (wasEmpty && !connection->outboundQueue.isEmpty()) {
        startDispatchCycleLocked(currentTime, connection);
    }
}

void InputDispatcher::startDispatchCycleLocked(nsecs_t currentTime,
        const sp<Connection>& connection) {
  
          EventEntry* eventEntry = dispatchEntry->eventEntry;
        switch (eventEntry->type) {
        case EventEntry::TYPE_KEY: {
            KeyEntry* keyEntry = static_cast<KeyEntry*>(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: {
                          // 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;
            }

int InputDispatcher::handleReceiveCallback(int fd, int events, void* data) {
    InputDispatcher* d = static_cast<InputDispatcher*>(data);
    ssize_t connectionIndex = d->mConnectionsByFd.indexOfKey(fd);
        sp<Connection> connection = d->mConnectionsByFd.valueAt(connectionIndex);
        if (!(events & (ALOOPER_EVENT_ERROR | ALOOPER_EVENT_HANGUP))) {
            if (!(events & ALOOPER_EVENT_INPUT)) {//仅仅对ALOOPER_EVENT_INPUT事件类型进行处理
                ALOGW("channel '%s' ~ Received spurious callback for unhandled poll event.  "
                        "events=0x%x", connection->getInputChannelName().c_str(), events);
                return 1;
            }
            nsecs_t currentTime = now();
            bool gotOne = false;
            status_t status;
            for (;;) {
                uint32_t seq;
                bool handled;
                status = connection->inputPublisher.receiveFinishedSignal(&seq, &handled);
                if (status) {
                    break;
                }
                d->finishDispatchCycleLocked(currentTime, connection, seq, handled);
                gotOne = true;
            }
            if (gotOne) {
                d->runCommandsLockedInterruptible();
                if (status == WOULD_BLOCK) {
                    return 1;
                }
            }
        }

status_t InputPublisher::publishMotionEvent(
        uint32_t seq,...... {
      return mChannel->sendMessage(&msg);
}

status_t InputConsumer::sendFinishedSignal(uint32_t seq, bool handled) {
  return sendUnchainedFinishedSignal(seq, handled);
}

status_t InputConsumer::sendUnchainedFinishedSignal(uint32_t seq, bool handled) {
    InputMessage msg;
    msg.header.type = InputMessage::TYPE_FINISHED;
    msg.body.finished.seq = seq;
    msg.body.finished.handled = handled;
    return mChannel->sendMessage(&msg);
}

status_t InputChannel::sendMessage(const InputMessage* msg) {
    size_t msgLength = msg->size();
    ssize_t nWrite;
    do {
        nWrite = ::send(mFd, msg, msgLength, MSG_DONTWAIT | MSG_NOSIGNAL);
    } while (nWrite == -1 && errno == EINTR);

public int addWindow(Session session, IWindow client, int seq, WindowManager.LayoutParams attrs, int viewVisibility, int displayId, Rect outContentInsets, Rect outStableInsets, Rect outOutsets, InputChannel outInputChannel) {

status_t InputChannel::openInputChannelPair(const String8& name,
        sp<InputChannel>& outServerChannel, sp<InputChannel>& outClientChannel) {
    int sockets[2];
    //真正创建socket对的地方【核心】
    if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets)) {
        ...
        return result;
    }

    int bufferSize = SOCKET_BUFFER_SIZE; //32k
    setsockopt(sockets[0], SOL_SOCKET, SO_SNDBUF, &bufferSize, sizeof(bufferSize));
    setsockopt(sockets[0], SOL_SOCKET, SO_RCVBUF, &bufferSize, sizeof(bufferSize));
    setsockopt(sockets[1], SOL_SOCKET, SO_SNDBUF, &bufferSize, sizeof(bufferSize));
    setsockopt(sockets[1], SOL_SOCKET, SO_RCVBUF, &bufferSize, sizeof(bufferSize));

    String8 serverChannelName = name;
    serverChannelName.append(" (server)");
    //创建InputChannel对象
    outServerChannel = new InputChannel(serverChannelName, sockets[0]);

    String8 clientChannelName = name;
    clientChannelName.append(" (client)");
    //创建InputChannel对象
    outClientChannel = new InputChannel(clientChannelName, sockets[1]);
    return OK;
}

InputChannel::InputChannel(const String8& name, int fd) :
        mName(name), mFd(fd) {
    //将socket设置成非阻塞方式
    int result = fcntl(mFd, F_SETFL, O_NONBLOCK);
}

status_t InputDispatcher::registerInputChannel(const sp<InputChannel>& inputChannel,
        const sp<InputWindowHandle>& inputWindowHandle, bool monitor) {
    { 
        AutoMutex _l(mLock);
        ...
        
        //创建Connection[见小节2.8.4]
        sp<Connection> connection = new Connection(inputChannel, inputWindowHandle, monitor);

        int fd = inputChannel->getFd();//fd为socket fd
        mConnectionsByFd.add(fd, connection);
        ...
        //将该fd添加到Looper监听[见小节2.8.5]
        mLooper->addFd(fd, 0, ALOOPER_EVENT_INPUT, handleReceiveCallback, this);
    }

    mLooper->wake(); //connection改变, 则唤醒looper
    return OK;
}

void NativeInputEventReceiver::setFdEvents(int events) {
  if (mFdEvents != events) {
      mFdEvents = events;
      int fd = mInputConsumer.getChannel()->getFd();//channel提供fd
      if (events) {
          //将socket客户端的fd添加到主线程的消息池【见小节3.6.1】
          mMessageQueue->getLooper()->addFd(fd, 0, events, this, NULL);//fd可读时触发本类的handleEvent回调
      } else {
          mMessageQueue->getLooper()->removeFd(fd);
      }
  }
}  

int Looper::pollInner(int timeoutMillis) {
    // Invoke all response callbacks.
    for (size_t i = 0; i < mResponses.size(); i++) {
    
             // Invoke the callback.  Note that the file descriptor may be closed by
            // the callback (and potentially even reused) before the function returns so
            // we need to be a little careful when removing the file descriptor afterwards.
            int callbackResult = response.request.callback->handleEvent(fd, events, data);
    }
}

int NativeInputEventReceiver::handleEvent(int receiveFd, int events, void* data) {
    
        if (events & ALOOPER_EVENT_INPUT) {
        JNIEnv* env = AndroidRuntime::getJNIEnv();
        status_t status = consumeEvents(env, false /*consumeBatches*/, -1, NULL);
        mMessageQueue->raiseAndClearException(env, "handleReceiveCallback");
        return status == OK || status == NO_MEMORY ? 1 : 0;
    }
}

status_t NativeInputEventReceiver::consumeEvents(JNIEnv* env,
        bool consumeBatches, nsecs_t frameTime, bool* outConsumedBatch) {
    
        for (;;) {
        uint32_t seq;
        InputEvent* inputEvent;
        int32_t displayId;
        status_t status = mInputConsumer.consume(&mInputEventFactory,
                consumeBatches, frameTime, &seq, &inputEvent, &displayId);
                    jobject inputEventObj;
            switch (inputEvent->getType()) {
            case AINPUT_EVENT_TYPE_KEY:
                if (kDebugDispatchCycle) {
                    ALOGD("channel '%s' ~ Received key event.", getInputChannelName().c_str());
                }
                inputEventObj = android_view_KeyEvent_fromNative(env,
                        static_cast<KeyEvent*>(inputEvent));
                break;

            case AINPUT_EVENT_TYPE_MOTION: {
                if (kDebugDispatchCycle) {
                    ALOGD("channel '%s' ~ Received motion event.", getInputChannelName().c_str());
                }
                MotionEvent* motionEvent = static_cast<MotionEvent*>(inputEvent);
                if ((motionEvent->getAction() & AMOTION_EVENT_ACTION_MOVE) && outConsumedBatch) {
                    *outConsumedBatch = true;
                }
                inputEventObj = android_view_MotionEvent_obtainAsCopy(env, motionEvent);
                break;
            }

            default:
                assert(false); // InputConsumer should prevent this from ever happening
                inputEventObj = NULL;
            }
            
                if (inputEventObj) {
                env->CallVoidMethod(receiverObj.get(),
                        gInputEventReceiverClassInfo.dispatchInputEvent, seq, inputEventObj,
                        displayId);
                }

    // Called from native code.
    @SuppressWarnings("unused")
    private void dispatchInputEvent(int seq, InputEvent event, int displayId) {
        mSeqMap.put(event.getSequenceNumber(), seq);
        onInputEvent(event, displayId);
    }

    public final void finishInputEvent(InputEvent event, boolean handled) {
           nativeFinishInputEvent(mReceiverPtr, seq, handled);
    }

static void nativeFinishInputEvent(JNIEnv* env, jclass clazz, jlong receiverPtr,
        jint seq, jboolean handled) {
    sp<NativeInputEventReceiver> receiver =
            reinterpret_cast<NativeInputEventReceiver*>(receiverPtr);
    status_t status = receiver->finishInputEvent(seq, handled);
}

status_t NativeInputEventReceiver::finishInputEvent(uint32_t seq, bool handled) {
    status_t status = mInputConsumer.sendFinishedSignal(seq, handled);
}