inputReader
- inputReader
inputReader
这个章节主要是围绕inputReader 、inputReaderThread进行的，老规矩先上时序图
通过前面我们已经知道了InputReader和InputReaderThread都是在InputManager的构造函数里面new出来的，然后InputReaderThread的启动是在SystemServer里面InputManagerService 调用start间接调到了InputManager的start，然后调到InputReaderThread.run()
frameworks/native/services/inputflinger/InputManager.cpp
InputManager::InputManager(
const sp<EventHubInterface>& eventHub,
const sp<InputReaderPolicyInterface>& readerPolicy,
const sp<InputDispatcherPolicyInterface>& dispatcherPolicy) {
mDispatcher = new InputDispatcher(dispatcherPolicy);
// 这里new 出来 InputReader
mReader = new InputReader(eventHub, readerPolicy, mDispatcher);
initialize();
}
InputManager::InputManager(
const sp<InputReaderInterface>& reader,
const sp<InputDispatcherInterface>& dispatcher) :
mReader(reader),
mDispatcher(dispatcher) {
initialize();
}
InputManager::~InputManager() {
stop();
}
// 这里new出来InputReaderThread，并且持有ReaderThread对象
void InputManager::initialize() {
mReaderThread = new InputReaderThread(mReader);
mDispatcherThread = new InputDispatcherThread(mDispatcher);
}
// 这里的start会在inputManagerServer里面间接调用
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;
}
// 启动ReaderThread线程
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;
}
后面跟着时序图走，前面已经启动了inputReaderThread后面线程启动就会走到InputReaderThread::threadLoop
bool InputReaderThread::threadLoop() {
// 调到了InputReader里面的loopOnce方法
mReader->loopOnce();
return true;
}
void InputReader::loopOnce() {
int32_t oldGeneration;
int32_t timeoutMillis;
bool inputDevicesChanged = false;
Vector<InputDeviceInfo> 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
// 获得事件, 没有事件就block在EventHub中的epoll处
size_t count = mEventHub->getEvents(timeoutMillis, mEventBuffer, EVENT_BUFFER_SIZE);
{ // acquire lock
AutoMutex _l(mLock);
mReaderIsAliveCondition.broadcast();
if (count) {
// 上面从EventHub得到EventBuffer后就会想着把事件处理后给到InputDispatcher，继续看这个方法
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.
// 这里会接收到不同的事件类型，然后调不同的notify（keyEvent、MotionEvent）去处理，在后面讲解
mQueuedListener->flush();
}
mEventHub->getEvents(timeoutMillis, mEventBuffer, EVENT_BUFFER_SIZE) 看看这个方法
size_t EventHub::getEvents(int timeoutMillis, RawEvent* buffer, size_t bufferSize) {
ALOG_ASSERT(bufferSize >= 1);
AutoMutex _l(mLock);
// 创建读取buffer
struct input_event readBuffer[bufferSize];
RawEvent* event = buffer;
size_t capacity = bufferSize;
// 在这个for循环里面读取设备节点里面的内容读到上面申请的buffer里面
for (;;) {
// 处理代码
if (eventItem.data.u32 == EPOLL_ID_WAKE) {
if (eventItem.events & EPOLLIN) {
ALOGV("awoken after wake()");
awoken = true;
char buffer[16];
ssize_t nRead;
do {
// 读取管道中的数据
nRead = read(mWakeReadPipeFd, buffer, sizeof(buffer));
} while ((nRead == -1 && errno == EINTR) || nRead == sizeof(buffer));
} else {
ALOGW("Received unexpected epoll event 0x%08x for wake read pipe.",
eventItem.events);
}
continue;
}
}
// All done, return the number of events we read.
// 返回已经被读取的buffer
return event - buffer;
}
EventHub算是一个比较大的内容了，大家可以参考一下这个文章，不过我觉得你看完整个文章后再去细追这个。
processEventsLocked(mEventBuffer, count);
void InputReader::processEventsLocked(const RawEvent* rawEvents, size_t count) {
for (const RawEvent* rawEvent = rawEvents; count;) {
int32_t type = rawEvent->type;
size_t batchSize = 1;
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
// 这里会根据不同的设备，发送不同的input事件
processEventsForDeviceLocked(deviceId, rawEvent, batchSize);
} else {
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;
}
}
void InputReader::processEventsForDeviceLocked(int32_t deviceId,
const RawEvent* rawEvents, size_t count) {
ssize_t deviceIndex = mDevices.indexOfKey(deviceId);
if (deviceIndex < 0) {
ALOGW("Discarding event for unknown deviceId %d.", deviceId);
return;
}
// KeyedVector<int32_t, InputDevice*> mDevices 这mDevices 里面add了不同的设备节点
InputDevice* device = mDevices.valueAt(deviceIndex);
if (device->isIgnored()) {
//ALOGD("Discarding event for ignored deviceId %d.", deviceId);
return;
}
device->process(rawEvents, count);
}
// 这里是往mDevices里面add的内容
InputDevice* InputReader::createDeviceLocked(int32_t deviceId, int32_t controllerNumber,
const InputDeviceIdentifier& identifier, uint32_t classes) {
InputDevice* device = new InputDevice(&mContext, deviceId, bumpGenerationLocked(),
controllerNumber, identifier, classes);
// External devices.
if (classes & INPUT_DEVICE_CLASS_EXTERNAL) {
device->setExternal(true);
}
// Devices with mics.
// 麦克风设备
if (classes & INPUT_DEVICE_CLASS_MIC) {
device->setMic(true);
}
// Switch-like devices.
// switch 类似的设备
if (classes & INPUT_DEVICE_CLASS_SWITCH) {
device->addMapper(new SwitchInputMapper(device));
}
// Scroll wheel-like devices.
// 鼠标设备
if (classes & INPUT_DEVICE_CLASS_ROTARY_ENCODER) {
device->addMapper(new RotaryEncoderInputMapper(device));
}
// Vibrator-like devices.
// 振动器设备
if (classes & INPUT_DEVICE_CLASS_VIBRATOR) {
device->addMapper(new VibratorInputMapper(device));
}
// Keyboard-like devices.
// 键盘
uint32_t keyboardSource = 0;
int32_t keyboardType = AINPUT_KEYBOARD_TYPE_NON_ALPHABETIC;
if (classes & INPUT_DEVICE_CLASS_KEYBOARD) {
keyboardSource |= AINPUT_SOURCE_KEYBOARD;
}
if (classes & INPUT_DEVICE_CLASS_ALPHAKEY) {
keyboardType = AINPUT_KEYBOARD_TYPE_ALPHABETIC;
}
if (classes & INPUT_DEVICE_CLASS_DPAD) {
keyboardSource |= AINPUT_SOURCE_DPAD;
}
if (classes & INPUT_DEVICE_CLASS_GAMEPAD) {
keyboardSource |= AINPUT_SOURCE_GAMEPAD;
}
if (keyboardSource != 0) {
device->addMapper(new KeyboardInputMapper(device, keyboardSource, keyboardType));
}
// Cursor-like devices.
if (classes & INPUT_DEVICE_CLASS_CURSOR) {
device->addMapper(new CursorInputMapper(device));
}
// Touchscreens and touchpad devices.
// 屏幕touch
if (classes & INPUT_DEVICE_CLASS_TOUCH_MT) {
device->addMapper(new MultiTouchInputMapper(device));
} else if (classes & INPUT_DEVICE_CLASS_TOUCH) {
device->addMapper(new SingleTouchInputMapper(device));
}
// Joystick-like devices.
if (classes & INPUT_DEVICE_CLASS_JOYSTICK) {
device->addMapper(new JoystickInputMapper(device));
}
// External stylus-like devices.
if (classes & INPUT_DEVICE_CLASS_EXTERNAL_STYLUS) {
device->addMapper(new ExternalStylusInputMapper(device));
}
return device;
}
接着上面device->process(rawEvents, count);我们会看到在InputReader.cpp里面有多个process方法
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);
}
}
void CursorScrollAccumulator::process(const RawEvent* rawEvent) {
if (rawEvent->type == EV_REL) {
switch (rawEvent->code) {
case REL_WHEEL:
mRelWheel = rawEvent->value;
break;
case REL_HWHEEL:
mRelHWheel = rawEvent->value;
break;
}
}
}
void SwitchInputMapper::process(const RawEvent* rawEvent) {
switch (rawEvent->type) {
case EV_SW:
processSwitch(rawEvent->code, rawEvent->value);
break;
case EV_SYN:
if (rawEvent->code == SYN_REPORT) {
sync(rawEvent->when);
}
}
}
.................
这就是我们前面吧这些InputMapper的子类都set到了mDevices里面了，我们这里假设调用的是
TouchInputMapper::process
frameworks/native/services/inputflinger/InputReader.cpp
void TouchInputMapper::process(const RawEvent* rawEvent) {
// 这几个都属于touch事件里面的
mCursorButtonAccumulator.process(rawEvent);
mCursorScrollAccumulator.process(rawEvent);
mTouchButtonAccumulator.process(rawEvent);
if (rawEvent->type == EV_SYN && rawEvent->code == SYN_REPORT) {
// 继续跟这里
sync(rawEvent->when);
}
}
void TouchInputMapper::sync(nsecs_t when) {
..........
processRawTouches(false /*timeout*/);
}
void TouchInputMapper::processRawTouches(bool timeout) {
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;
}
// 这里
cookAndDispatch(mCurrentRawState.when);
}
}
void TouchInputMapper::cookAndDispatch(nsecs_t when) {
if (!mCurrentMotionAborted) {
dispatchButtonRelease(when, policyFlags);
dispatchHoverExit(when, policyFlags);
// 这里
dispatchTouches(when, policyFlags);
dispatchHoverEnterAndMove(when, policyFlags);
dispatchButtonPress(when, policyFlags);
}
}
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 {
// Dispatch pointer up events.
while (!upIdBits.isEmpty()) {
uint32_t upId = upIdBits.clearFirstMarkedBit();
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);
// 这里
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);
}
}
}
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);
}
}
// 这里构造出NotifyMotionArgs 对象
NotifyMotionArgs args(when, getDeviceId(), source, policyFlags,
action, actionButton, flags, metaState, buttonState, edgeFlags,
mViewport.displayId, deviceTimestamp, pointerCount, pointerProperties, pointerCoords,
xPrecision, yPrecision, downTime);
// 然后这里又调回到QueuedInputListener中，将这个对象set到mArgsQueue队列里面
getListener()->notifyMotion(&args);
}
frameworks/native/services/inputflinger/InputListener.cpp
void QueuedInputListener::notifyMotion(const NotifyMotionArgs* args) {
mArgsQueue.push(new NotifyMotionArgs(*args));
}
接着看
mQueuedListener->flush();
void QueuedInputListener::flush() {
size_t count = mArgsQueue.size();
for (size_t i = 0; i < count; i++) {
NotifyArgs* args = mArgsQueue[i];
这个mInnerListener就是我们的InputDispatcher对象
args->notify(mInnerListener);
delete args;
}
mArgsQueue.clear();
}
void NotifyMotionArgs::notify(const sp<InputListenerInterface>& listener) const {
// 调用到InputDispatcher的notifyMotion
listener->notifyMotion(this);
}
从上面的文章我们就看到了整个从InputReaderThread --> EventHub读取设备节点 --> InputReader --> inputDispatcher
