C++纯虚类与工厂的应用

一、纯虚类

hardware/amlogic/camera/inc/CameraHal.h

class CameraAdapter: public FrameNotifier, public virtual RefBase
{
  //add by [email protected]                                                                                                                       
 virtual bool getPixelFormat(char* ResolutionList, bool bIsPictureMode) = 0;
 virtual int v4l2QueryControl(int control, struct v4l2_queryctrl *queryctrl) = 0;
 virtual int v4l2GetControl(int control) = 0;
 virtual int v4l2SetControl(int control, int value) = 0; 
 int mInterpolationSize;
 //end [email protected] 
}

hardware/amlogic/camera/inc/BaseCameraAdapter.h

class BaseCameraAdapter : public CameraAdapter
{
  //add by [email protected]
  virtual bool getPixelFormat(char* ResolutionList, bool bIsPictureMode) = 0;
  virtual int v4l2QueryControl(int control, struct v4l2_queryctrl *queryctrl) = 0;
  virtual int v4l2GetControl(int control) = 0;
  virtual int v4l2SetControl(int control, int value) = 0;
  //end [email protected]
}

二、继承类

hardware/amlogic/camera/vircam/inc/V4LCamAdpt.h

class V4LCamAdpt : public BaseCameraAdapter
{
  //add by [email protected]
  virtual bool getPixelFormat(char* ResolutionList, bool bIsPictureMode);
  virtual int v4l2QueryControl(int control, struct v4l2_queryctrl *queryctrl);
  virtual int v4l2GetControl(int control);
  virtual int v4l2SetControl(int control, int value);
   //end [email protected]
}

hardware/amlogic/camera/inc/V4LCameraAdapter/V4LCameraAdapter.h

class V4LCameraAdapter : public BaseCameraAdapter
{
  //add by [email protected]                                                                                                                         
  virtual bool getPixelFormat(char* ResolutionList, bool bIsPictureMode);
  virtual int v4l2QueryControl(int control, struct v4l2_queryctrl *queryctrl);
  virtual int v4l2GetControl(int control);
  virtual int v4l2SetControl(int control, int value);
  //end [email protected]
}

三、使用

1.分别是虚拟和实际

hardware/amlogic/camera/CameraHal.cpp

status_t CameraHal::initialize(CameraProperties::Properties* properties)
{
  mCameraAdapter = CameraAdapter_Factory(sensor_index);
}

hardware/amlogic/camera/vircam/VirtualCamHal.cpp

status_t VirtualCamHal::initialize(CameraProperties::Properties* properties)
{
  mCameraAdapter = CameraAdapter_Factory(sensor_index);
}

2.工厂模式的定义

hardware/amlogic/camera/V4LCameraAdapter/V4LCameraAdapter.cpp

extern "C" CameraAdapter* CameraAdapter_Factory(size_t sensor_index)
{
  if( sensor_index == (size_t)(iCamerasNum)){
    adapter = new V4LCamAdpt(sensor_index);
  }else{
    adapter = new V4LCameraAdapter(sensor_index);
  }
}