[PATCH v3] qcam: Automatically select the camera if only one is available

[Kieran Bingham]

Quoting Stanislaw Gruszka (2024-10-22 11:24:48)
> When only a single camera is available, showing the camera selection
> dialog is unnecessary. It's better to automatically select the available
> camera without prompting the user for input.
> 
> Co-developed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka at linux.intel.com>
> ---
> v2:
> - Avoid cm_->cameras().size() vs cm_->cameras()[0] race condition
>   using custom loop.
> - Update in code comment
> v3: 
> - Avoid TOCTOU race using shared_ptr vector copy
> - Use Laurent comment wording
> 
>  src/apps/qcam/main_window.cpp | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/src/apps/qcam/main_window.cpp b/src/apps/qcam/main_window.cpp
> index 5144c6b3..de487672 100644
> --- a/src/apps/qcam/main_window.cpp
> +++ b/src/apps/qcam/main_window.cpp
> @@ -298,13 +298,19 @@ int MainWindow::openCamera()
>         std::string cameraName;
>  
>         /*
> -        * Use the camera specified on the command line, if any, or display the
> -        * camera selection dialog box otherwise.
> +        * If a camera is specified on the command line, get it. Otherwise, if
> +        * only one camera is available, pick it automatically, else, display
> +        * the selector dialog box.
>          */
> -       if (options_.isSet(OptCamera))
> +       if (options_.isSet(OptCamera)) {
>                 cameraName = static_cast<std::string>(options_[OptCamera]);
> -       else
> -               cameraName = chooseCamera();
> +       } else {
> +               std::vector<std::shared_ptr<Camera>> cameras = cm_->cameras();
> +               if (cameras.size() == 1)
> +                       cameraName = cameras[0]->id();
> +               else
> +                       cameraName = chooseCamera();
> +       }

Ok, now I see how the toctou is easier to fix like this ;-)

I like this - clean and short and does what it needs.


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

>  
>         if (cameraName == "")
>                 return -EINVAL;
> -- 
> 2.43.0
>