[libcamera-devel] [PATCH] cam: Use structured bindings in range-based for loops

[Kieran Bingham]

Quoting Nejc Galof (2022-02-20 00:52:57)
> Use structured bindings range-based for loops for better readability.
> ---
>  src/cam/camera_session.cpp | 21 +++++++--------------
>  1 file changed, 7 insertions(+), 14 deletions(-)
> 
> diff --git a/src/cam/camera_session.cpp b/src/cam/camera_session.cpp
> index 1bf460fa..0428b538 100644
> --- a/src/cam/camera_session.cpp
> +++ b/src/cam/camera_session.cpp
> @@ -120,10 +120,7 @@ CameraSession::~CameraSession()
>  
>  void CameraSession::listControls() const
>  {
> -       for (const auto &ctrl : camera_->controls()) {
> -               const ControlId *id = ctrl.first;
> -               const ControlInfo &info = ctrl.second;
> -
> +       for (const auto &[id, info] : camera_->controls()) {

I have continually disliked '.first' and '.second' so I'm happy to see
this.

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


I still prefer the structured bindings, but where we explicitly cast
the type to .first and .second does help show the type information, but
that can also be determined/conveyed from the return type of the
iterator/getters - so I still think this is fine.


>                 std::cout << "Control: " << id->name() << ": "
>                           << info.toString() << std::endl;
>         }
> @@ -131,9 +128,8 @@ void CameraSession::listControls() const
>  
>  void CameraSession::listProperties() const
>  {
> -       for (const auto &prop : camera_->properties()) {
> -               const ControlId *id = properties::properties.at(prop.first);
> -               const ControlValue &value = prop.second;
> +       for (const auto &[key, value] : camera_->properties()) {
> +               const ControlId *id = properties::properties.at(key);
>  
>                 std::cout << "Property: " << id->name() << " = "
>                           << value.toString() << std::endl;
> @@ -374,10 +370,7 @@ void CameraSession::processRequest(Request *request)
>              << std::setw(6) << std::setfill('0') << ts / 1000 % 1000000
>              << " (" << std::fixed << std::setprecision(2) << fps << " fps)";
>  
> -       for (auto it = buffers.begin(); it != buffers.end(); ++it) {
> -               const Stream *stream = it->first;
> -               FrameBuffer *buffer = it->second;
> -
> +       for (const auto &[stream, buffer] : buffers) {
>                 const FrameMetadata &metadata = buffer->metadata();
>  
>                 info << " " << streamNames_[stream]
> @@ -401,10 +394,10 @@ void CameraSession::processRequest(Request *request)
>  
>         if (printMetadata_) {
>                 const ControlList &requestMetadata = request->metadata();
> -               for (const auto &ctrl : requestMetadata) {
> -                       const ControlId *id = controls::controls.at(ctrl.first);
> +               for (const auto &[key, value] : requestMetadata) {
> +                       const ControlId *id = controls::controls.at(key);
>                         std::cout << "\t" << id->name() << " = "
> -                                 << ctrl.second.toString() << std::endl;
> +                                 << value.toString() << std::endl;
>                 }
>         }
>  
> -- 
> 2.17.1
>