[libcamera-devel] [PATCH 04/11] libcamera: camera_manager: Make the class a singleton

[Jacopo Mondi]

Hi Laurent,

On Sun, Jan 06, 2019 at 04:33:21AM +0200, Laurent Pinchart wrote:
> There can only be a single camera manager instance in the application.
> Creating it as a singleton helps avoiding mistakes. It also allows the
> camera manager to be used as a storage of global data, such as the
> future event dispatcher.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  include/libcamera/camera_manager.h |  6 ++++--
>  src/libcamera/camera_manager.cpp   | 15 +++++++++++++++
>  test/list.cpp                      |  4 +---
>  3 files changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/include/libcamera/camera_manager.h b/include/libcamera/camera_manager.h
> index 2768a5bd2384..56a3f32d8b6f 100644
> --- a/include/libcamera/camera_manager.h
> +++ b/include/libcamera/camera_manager.h
> @@ -19,15 +19,17 @@ class PipelineHandler;
>  class CameraManager
>  {
>  public:
> -	CameraManager();
> -
>  	int start();
>  	void stop();
>
>  	std::vector<std::string> list() const;
>  	Camera *get(const std::string &name);
>
> +	static CameraManager *instance();
> +
>  private:
> +	CameraManager();
> +
>  	DeviceEnumerator *enumerator_;
>  	std::vector<PipelineHandler *> pipes_;
>  };
> diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp
> index 50a805fc665c..db2bc4b7424e 100644
> --- a/src/libcamera/camera_manager.cpp
> +++ b/src/libcamera/camera_manager.cpp
> @@ -161,4 +161,19 @@ Camera *CameraManager::get(const std::string &name)
>  	return nullptr;
>  }
>
> +/**
> + * \brief Retrieve the camera manager instance
> + *
> + * The CameraManager is a singleton and can't be constructed manually. This
> + * function can instead be used to retrieve the single global instance of the

nit: s/can/shall

Apart from this minor thing, one other thing I wonder about is copy
constructors, should we set them to "= delete" ?

With this clarified:
Reviewed-by: Jacopo Mondi <jacopo at jmondi.org>

Thanks
  j


> + * manager.
> + *
> + * \return The camera manager instance
> + */
> +CameraManager *CameraManager::instance()
> +{
> +	static CameraManager manager;
> +	return &manager;
> +}
> +
>  } /* namespace libcamera */
> diff --git a/test/list.cpp b/test/list.cpp
> index 39b8a41d1fef..49610c697c63 100644
> --- a/test/list.cpp
> +++ b/test/list.cpp
> @@ -19,7 +19,7 @@ class ListTest : public Test
>  protected:
>  	int init()
>  	{
> -		cm = new CameraManager();
> +		cm = CameraManager::instance();
>  		if (!cm)
>  			return -ENOMEM;
>
> @@ -43,8 +43,6 @@ protected:
>  	void cleanup()
>  	{
>  		cm->stop();
> -
> -		delete cm;
>  	}
>
>  private:
> --
> Regards,
>
> Laurent Pinchart
>
> _______________________________________________
> libcamera-devel mailing list
> libcamera-devel at lists.libcamera.org
> https://lists.libcamera.org/listinfo/libcamera-devel
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