Android输入系统(二)

Android输入系统(二)

Android输入系统二
启动InputManagerService
InputManagerService构造函数

1nativeInit
11NativeInputManager
111EventHub

112InputManager
1121InputDispatcher

111211getDispatcherConfiguration

1122InputReader

1123initialize

2inputManagerstart
1nativeStart
11NativeInputManagerstart

前言:

今天大概来说说启动流程

由于我们前面文章提到过,SystemServer中启动了所有的Java服务,那么当然也包括输入系统的Java服务

启动InputManagerService

@(/frameworks/base/services/java/com/android/server/SystemServer.java)

inputManager = new InputManagerService(context);//[1]
wm = WindowManagerService.main(context, inputManager,
mFactoryTestMode != FactoryTest.FACTORY_TEST_LOW_LEVEL,
!mFirstBoot, mOnlyCore);
ServiceManager.addService(Context.WINDOW_SERVICE, wm);
ServiceManager.addService(Context.INPUT_SERVICE, inputManager);
mSystemServiceManager.startService(VrManagerService.class);
mActivityManagerService.setWindowManager(wm);
inputManager.setWindowManagerCallbacks(wm.getInputMonitor());
inputManager.start();//[2]

上面代码可以看出InputManagerService和WMS有着密不可分的关系,我们暂时不去深究内部关系,重点关心输入系统的结构上

1.InputManagerService构造函数

public InputManagerService(Context context) {
this.mContext = context;
this.mHandler = new InputManagerHandler(DisplayThread.get().getLooper());//对DisplayThread线程进行消息处理
mUseDevInputEventForAudioJack =
context.getResources().getBoolean(R.bool.config_useDevInputEventForAudioJack);
mPtr = nativeInit(this, mContext, mHandler.getLooper().getQueue());//[1.1]指向native input manager service object.
LocalServices.addService(InputManagerInternal.class, new LocalService());//将服务添加到本地服务的全局注册表
}

小结:

- 使用DisplayThread线程进行消息处理

- 指向native层的InputManagerService

1.1nativeInit()

@(com_android_server_input_InputManagerService.cpp)

static jlong nativeInit(JNIEnv* env, jclass /* clazz */,
jobject serviceObj, jobject contextObj, jobject messageQueueObj) {
sp<MessageQueue> messageQueue = android_os_MessageQueue_getMessageQueue(env, messageQueueObj);//得到DisplayThread的MessageQueue
if (messageQueue == NULL) {
jniThrowRuntimeException(env, "MessageQueue is not initialized.");
return 0;
}
NativeInputManager* im = new NativeInputManager(contextObj, serviceObj,
messageQueue->getLooper());//[1.1.1]创建Native层的NativeInputManager对象
im->incStrong(0);
return reinterpret_cast<jlong>(im);
}

小结:

- 传递进来的是java层的InputManagerService对象引用和全局Context和DisplayThread的Loop

- 创建Ntive层的NativeInputManager对象

1.1.1NativeInputManager

@(com_android_server_input_InputManagerService.cpp)

NativeInputManager::NativeInputManager(jobject contextObj,
jobject serviceObj, const sp<Looper>& 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;
}
mInteractive = true;
sp<EventHub> eventHub = new EventHub();//创建EventHbu对象[1.1.1.1]
mInputManager = new InputManager(eventHub, this, this);//[1.1.1.2]创建InputManager对象
}

小结:

- 将looper给成员变量mLooper,Context给mContextObj,java层的InputManagerService引用给mServiceObj

- 创建EventHub对象

- 创建InputManager对象,传入NativeInputManager和eventHub,其中NativeInputManager存有java层的InputManagerService对象引用和全局Context和DisplayThread的Loop

1.1.1.1EventHub

@(framework\native\services\inputflinger\EventHbu.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);

mEpollFd = epoll_create(EPOLL_SIZE_HINT);//创建epoll
...
mINotifyFd = inotify_init();//初始化inotify
int result = inotify_add_watch(mINotifyFd, DEVICE_PATH, IN_DELETE | IN_CREATE);//添加观测目录"/dev/input"
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);//将mINotifyFd添加到epoll中
int wakeFds[2];//两个文件句柄,因为要跨进程所以必须将其中一个传递到另外一个非父子进程中
result = pipe(wakeFds);//通过管道实现
mWakeReadPipeFd = wakeFds[0];
mWakeWritePipeFd = wakeFds[1];
result = fcntl(mWakeReadPipeFd, F_SETFL, O_NONBLOCK);//设置管道的读写是非阻塞
result = fcntl(mWakeWritePipeFd, F_SETFL, O_NONBLOCK);
...
eventItem.data.u32 = EPOLL_ID_WAKE;
//将管道读添加到epoll中
result = epoll_ctl(mEpollFd, EPOLL_CTL_ADD, mWakeReadPipeFd, &eventItem);
...
int major, minor;
getLinuxRelease(&major, &minor);
...
mUsingEpollWakeup = major > 3 || (major == 3 && minor >= 5);
}

小结:

- 创建epoll用于监听文件的更新情况

- 创建inotify用于监听目录的更新情况

- 创建管道用于进程间通信

1.1.1.2InputManager

InputManager::InputManager(
const sp<EventHubInterface>& eventHub,
const sp<InputReaderPolicyInterface>& readerPolicy,
const sp<InputDispatcherPolicyInterface>& dispatcherPolicy) {
mDispatcher = new InputDispatcher(dispatcherPolicy);//[1.1.1.2.1]创建InputDispatcher
mReader = new InputReader(eventHub, readerPolicy, mDispatcher);//[1.1.1.2.2]创InputReader
initialize();//[1.1.1.2.3]
}
---------------------------------------------------------------------------------------------
>这里注意传递new InputReader传递进来的参数是NativeInputManager.this,对照参数的接收
class NativeInputManager : public virtual RefBase,
public virtual InputReaderPolicyInterface,
public virtual InputDispatcherPolicyInterface,
public virtual PointerControllerPolicyInterface {

小结:

- 创建InputDispatcher

- 创建InputReader并且创建InputReaderThread和InputDispatcherThread两个线程

1.1.1.2.1InputDispatcher

InputDispatcher::InputDispatcher(const sp<InputDispatcherPolicyInterface>& 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);//创建Loop
mKeyRepeatState.lastKeyEntry = NULL;
policy->getDispatcherConfiguration(&mConfig);//[1.1.1.2.1.1]//policy是NativeInputManager.this
}

#1.1.1.2.1.1getDispatcherConfiguration()

void NativeInputManager::getDispatcherConfiguration(InputDispatcherConfiguration* outConfig) {
JNIEnv* env = jniEnv();
jint keyRepeatTimeout = env->CallIntMethod(mServiceObj,
gServiceClassInfo.getKeyRepeatTimeout);
if (!checkAndClearExceptionFromCallback(env, "getKeyRepeatTimeout")) {
outConfig->keyRepeatTimeout = milliseconds_to_nanoseconds(keyRepeatTimeout);
}
jint keyRepeatDelay = env->CallIntMethod(mServiceObj,
gServiceClassInfo.getKeyRepeatDelay);
if (!checkAndClearExceptionFromCallback(env, "getKeyRepeatDelay")) {
outConfig->keyRepeatDelay = milliseconds_to_nanoseconds(keyRepeatDelay);
}
}

1.1.1.2.2InputReader

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) {
mQueuedListener = new QueuedInputListener(listener);

{ // acquire lock
AutoMutex _l(mLock);
refreshConfigurationLocked(0);
updateGlobalMetaStateLocked();
} // release lock
}

1.1.1.2.3initialize()

创建两个线程

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

2inputManager.start()

public void start() {
nativeStart(mPtr);//[2.1]
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();//更新触摸点速度
updateShowTouchesFromSettings();//显示触摸点
updateAccessibilityLargePointerFromSettings();//更新是否允许触摸点
}

2.1nativeStart()

@(com_android_server_input_InputManagerService.cpp)

//注意这里的ptr是mPtr = nativeInit(this, mContext, mHandler.getLooper().getQueue());
//记录的是NativeInputManager对象
static void nativeStart(JNIEnv* env, jclass /* clazz */, jlong ptr) {
NativeInputManager* im = reinterpret_cast<NativeInputManager*>(ptr);
status_t result = im->getInputManager()->start();
if (result) {
jniThrowRuntimeException(env, "Input manager could not be started.");
}
}

2.1.1NativeInputManager.start()

@(InputManager.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;
}

运行NativeInputManager中的两个线程

mReaderThread = new InputReaderThread(mReader);

mDispatcherThread = new InputDispatcherThread(mDispatcher);

总结:

java层:

- 在InputManagerService的构造中传入DisplayThread线程的Looper.使用DisplayThread的Message消息队列

- 加入本地服务中

- 将InputManagerServce传递到WMS中

- 将InputManagerService添加到ServiceManager中

- 启动inputManager服务

Native层:

- 创建Native层的NativeInputManager就是Java层的InputManagerService

- NativeInputManager对象持有Java层的Context,InputManagerService.this等等

- 创建EventHub,InputManager

- 使用epoll,inotify机制

- 开启两个线程,一个用于接收事件派发,一个用于获取事件处理