Cubietruck---18.input子系统启动流程分析

一. Input 系统的初始化
1. InputManagerService是由SystemServer建立的
在frameworks/base/services/java/com/android/server/SystemServer.java中

class ServerThread extends Thread {
 @Override
    public void run() {
      HandlerThread wmHandlerThread = new HandlerThread("WindowManager");
      wmHandlerThread.start();
      Handler wmHandler = new Handler(wmHandlerThread.getLooper());
      context = ActivityManagerService.main(factoryTest);

      InputManagerService inputManager = null;
      //1.1 new的过程创建InputReader InputDispatcher和EventHub
      inputManager = new InputManagerService(context, wmHandler);
      inputManager.setWindowManagerCallbacks(wm.getInputMonitor());
      //1.2 start的过程:将InputReader与InputDispatcher的线程跑起来
      inputManager.start();

      display.setInputManager(inputManager);
     }
}

1.1 new的调用过程
SystemServer:: new InputManagerService
  --> InputManagerService构造函数
在frameworks/base/services/java/com/android/server/input/InputManagerService.java中

public InputManagerService(Context context, Handler handler)
{
    this.mContext = context;
    this.mHandler = new InputManagerHandler(handler.getLooper());
    mPtr = nativeInit(this, mContext, mHandler.getLooper().getQueue());
}

SystemServer:: new InputManagerService
  --> InputManagerService构造函数
    --> nativeInit     ;;通过jni调用
在frameworks/base/services/jni/com_android_server_input_InputManagerService.cpp 中

static jint 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(serviceObj);
    return reinterpret_cast<jint>(im);
}

SystemServer:: new InputManagerService
  --> InputManagerService构造函数
    --> nativeInit     ;;通过jni调用NativeInputManager的构造
        --> NativeInputManager ;;new一个EventHub和InputManager
在frameworks/base/services/jni/com_android_server_input_InputManagerService.cpp中

NativeInputManager::NativeInputManager(jobject contextObj, jobject serviceObj, const sp<Looper>& looper) : mLooper(looper)
{
    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;

    sp<EventHub> eventHub = new EventHub();
    mInputManager = new InputManager(eventHub, this, this);
}

SystemServer:: new InputManagerService
  --> InputManagerService构造函数
    --> nativeInit         ;;通过jni调用NativeInputManager的构造
        --> NativeInputManager构造 ;;new一个EventHub和InputManager
          --> InputManager构造       ;;new InputDispatcher和InputReader及其线程
在frameworks/base/services/input/InputManager.cpp中
在InputManager的构造函数中,又建立了InputDispatcher和InputReader

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();
}

同时又建立了InputDispatcher和InputReader各自的线程

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

1.2 start的调用过程
SystemServer:: InputManagerService.start
  --> InputManagerService::start   ;;调用jni
在frameworks/base/services/java/com/android/server/input/InputManagerService.java中

public void start() {
    nativeStart(mPtr);
}

SystemServer:: InputManagerService.start
  --> InputManagerService::start   ;;调用jni
    --> nativeStart         ;;通过jni调用NativeInputManager的start
在frameworks/base/services/jni/com_android_server_input_InputManagerService.cpp 中

public void start() {
    nativeStart(mPtr);
}

SystemServer:: InputManagerService.start
  --> InputManagerService::start   ;;调用jni
    --> nativeStart         ;;通过jni调用NativeInputManager的start
        --> NativeInputManager::nativeStart ;;调用InputManager的start
在frameworks/base/services/jni/com_android_server_input_InputManagerService.cpp中

static void nativeStart(JNIEnv* env, jclass clazz, jint ptr) {
    NativeInputManager* im = reinterpret_cast<NativeInputManager*>(ptr);
    status_t result = im->getInputManager()->start();
}

SystemServer:: InputManagerService.start
  --> InputManagerService::start   ;;调用jni
    --> nativeStart         ;;通过jni调用NativeInputManager的start
        --> NativeInputManager::nativeStart ;;调用InputManager的start
          --> InputManager::start       ;;让InputDispatcher和InputReader的线程跑起来
在frameworks/base/services/input/InputManager.cpp中

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