android Jelly Bean版本如何将camera service修改为强占式

实现强占式camera service，当某些应用（如手电筒）在后台打开camera后，当camera app open camera时可以强占被后台应用占有的camera.


1. 修改CameraService.cpp (frameworks/av/services/camera/libcameraservice/)
文件的connect()方法，将
原来的
    Mutex::Autolock lock(mServiceLock);
    if (mClient[cameraId] != 0) {
        client = mClient[cameraId].promote();
        if (client != 0) {
            if (cameraClient->asBinder() == client->getCameraClient()->asBinder()) {
                LOG1("CameraService::connect X (pid %d) (the same client)",
                     callingPid);
                return client;
            } else {
                ALOGW("CameraService::connect X (pid %d) rejected (existing client).",
                      callingPid);
                return NULL;
            }
        }
        mClient[cameraId].clear();
    }
修改为：
   
    if (mClient[cameraId] != 0) {
        client = mClient[cameraId].promote();
        if (client != 0) {
                LOG1("CameraService::connect X (pid %d)  disconnect the old client", callingPid);
               client->disconnect();
        }
        mClient[cameraId].clear();
    }
   Mutex::Autolock lock(mServiceLock);
 
2. 修改CameraClient.cpp(frameworks/av/services/camera/libcameraservice/)
文件的disconnect()方法:
将原来的：
    if (callingPid != mClientPid && callingPid != mServicePid) {
        ALOGW("different client - don‘t disconnect");
        return;
    }
修改为：
    if (callingPid != mClientPid && callingPid != mServicePid) {
        ALOGW("different client but  preemptive camera service！ ");
        //return;
    }