[libcamera-devel] [PATCH 1/2] libcamera: v4l2_subdevice: Return a unique pointer from fromEntityName()

[Kieran Bingham]

Hi Laurent,

On 08/12/2020 01:49, Laurent Pinchart wrote:
> The fromEntityName() function returns a pointer to a newly allocated
> V4L2Subdevice instance, which must be deleted by the caller. This opens
> the door to memory leaks. Return a unique pointer instead, which conveys
> the API semantics better than a sentence in the documentation.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  include/libcamera/internal/v4l2_subdevice.h   |  5 +++--
>  src/libcamera/pipeline/ipu3/imgu.cpp          |  2 +-
>  src/libcamera/pipeline/rkisp1/rkisp1.cpp      |  6 ++----
>  src/libcamera/pipeline/rkisp1/rkisp1_path.cpp |  3 +--
>  src/libcamera/pipeline/rkisp1/rkisp1_path.h   |  3 ++-
>  src/libcamera/v4l2_subdevice.cpp              | 10 ++++------
>  6 files changed, 13 insertions(+), 16 deletions(-)
> 
> diff --git a/include/libcamera/internal/v4l2_subdevice.h b/include/libcamera/internal/v4l2_subdevice.h
> index 02ee3e914a8b..eb25fa2fd01b 100644
> --- a/include/libcamera/internal/v4l2_subdevice.h
> +++ b/include/libcamera/internal/v4l2_subdevice.h
> @@ -7,6 +7,7 @@
>  #ifndef __LIBCAMERA_INTERNAL_V4L2_SUBDEVICE_H__
>  #define __LIBCAMERA_INTERNAL_V4L2_SUBDEVICE_H__
>  
> +#include <memory>
>  #include <string>
>  #include <vector>
>  
> @@ -60,8 +61,8 @@ public:
>  	int setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
>  		      Whence whence = ActiveFormat);
>  
> -	static V4L2Subdevice *fromEntityName(const MediaDevice *media,
> -					     const std::string &entity);
> +	static std::unique_ptr<V4L2Subdevice>
> +	fromEntityName(const MediaDevice *media, const std::string &entity);
>  
>  protected:
>  	std::string logPrefix() const override;
> diff --git a/src/libcamera/pipeline/ipu3/imgu.cpp b/src/libcamera/pipeline/ipu3/imgu.cpp
> index a4d74a62f69a..bfe9624c7797 100644
> --- a/src/libcamera/pipeline/ipu3/imgu.cpp
> +++ b/src/libcamera/pipeline/ipu3/imgu.cpp
> @@ -343,7 +343,7 @@ int ImgUDevice::init(MediaDevice *media, unsigned int index)
>  	 * by the match() function: no need to check for newly created
>  	 * video devices and subdevice validity here.
>  	 */
> -	imgu_.reset(V4L2Subdevice::fromEntityName(media, name_));
> +	imgu_ = V4L2Subdevice::fromEntityName(media, name_);

I like this,

>  	ret = imgu_->open();
>  	if (ret)
>  		return ret;
> diff --git a/src/libcamera/pipeline/rkisp1/rkisp1.cpp b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> index 6e74a49abfda..bcfe6c0514ab 100644
> --- a/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> +++ b/src/libcamera/pipeline/rkisp1/rkisp1.cpp
> @@ -217,7 +217,7 @@ private:
>  	int freeBuffers(Camera *camera);
>  
>  	MediaDevice *media_;
> -	V4L2Subdevice *isp_;
> +	std::unique_ptr<V4L2Subdevice> isp_;
>  	V4L2VideoDevice *param_;
>  	V4L2VideoDevice *stat_;
>  
> @@ -599,8 +599,7 @@ CameraConfiguration::Status RkISP1CameraConfiguration::validate()
>  }
>  
>  PipelineHandlerRkISP1::PipelineHandlerRkISP1(CameraManager *manager)
> -	: PipelineHandler(manager), isp_(nullptr), param_(nullptr),
> -	  stat_(nullptr)
> +	: PipelineHandler(manager), param_(nullptr), stat_(nullptr)
>  {
>  }
>  
> @@ -608,7 +607,6 @@ PipelineHandlerRkISP1::~PipelineHandlerRkISP1()
>  {
>  	delete param_;
>  	delete stat_;
> -	delete isp_;

And I like this.


>  }
>  
>  /* -----------------------------------------------------------------------------
> diff --git a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
> index 3f77b1c12f9d..e05d9dd657cd 100644
> --- a/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
> +++ b/src/libcamera/pipeline/rkisp1/rkisp1_path.cpp
> @@ -24,14 +24,13 @@ RkISP1Path::RkISP1Path(const char *name, const Span<const PixelFormat> &formats,
>  		       const Size &minResolution, const Size &maxResolution)
>  	: name_(name), running_(false), formats_(formats),
>  	  minResolution_(minResolution), maxResolution_(maxResolution),
> -	  resizer_(nullptr), video_(nullptr), link_(nullptr)
> +	  video_(nullptr), link_(nullptr)

and this.

This makes a lot of sense as far as I can see.

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

>  {
>  }
>  
>  RkISP1Path::~RkISP1Path()
>  {
>  	delete video_;
> -	delete resizer_;
>  }
>  
>  bool RkISP1Path::init(MediaDevice *media)
> diff --git a/src/libcamera/pipeline/rkisp1/rkisp1_path.h b/src/libcamera/pipeline/rkisp1/rkisp1_path.h
> index 8f443e5179f6..f06ac5a731cc 100644
> --- a/src/libcamera/pipeline/rkisp1/rkisp1_path.h
> +++ b/src/libcamera/pipeline/rkisp1/rkisp1_path.h
> @@ -7,6 +7,7 @@
>  #ifndef __LIBCAMERA_PIPELINE_RKISP1_PATH_H__
>  #define __LIBCAMERA_PIPELINE_RKISP1_PATH_H__
>  
> +#include <memory>
>  #include <vector>
>  
>  #include <libcamera/camera.h>
> @@ -65,7 +66,7 @@ private:
>  	const Size minResolution_;
>  	const Size maxResolution_;
>  
> -	V4L2Subdevice *resizer_;
> +	std::unique_ptr<V4L2Subdevice> resizer_;
>  	V4L2VideoDevice *video_;
>  	MediaLink *link_;
>  };
> diff --git a/src/libcamera/v4l2_subdevice.cpp b/src/libcamera/v4l2_subdevice.cpp
> index 85d00c246f5e..721ff5a92a2b 100644
> --- a/src/libcamera/v4l2_subdevice.cpp
> +++ b/src/libcamera/v4l2_subdevice.cpp
> @@ -446,19 +446,17 @@ int V4L2Subdevice::setFormat(unsigned int pad, V4L2SubdeviceFormat *format,
>   * \param[in] media The media device where the entity is registered
>   * \param[in] entity The media entity name
>   *
> - * Releasing memory of the newly created instance is responsibility of the
> - * caller of this function.
> - *
>   * \return A newly created V4L2Subdevice on success, nullptr otherwise
>   */
> -V4L2Subdevice *V4L2Subdevice::fromEntityName(const MediaDevice *media,
> -					     const std::string &entity)
> +std::unique_ptr<V4L2Subdevice>
> +V4L2Subdevice::fromEntityName(const MediaDevice *media,
> +			      const std::string &entity)
>  {
>  	MediaEntity *mediaEntity = media->getEntityByName(entity);
>  	if (!mediaEntity)
>  		return nullptr;
>  
> -	return new V4L2Subdevice(mediaEntity);
> +	return std::make_unique<V4L2Subdevice>(mediaEntity);
>  }
>  
>  std::string V4L2Subdevice::logPrefix() const
> 

-- 
Regards
--
Kieran