[libcamera-devel] [PATCH] android: jpeg: Utilise compiler specific nodiscard

[Laurent Pinchart]

Hi Kieran,

Thank you for the patch.

On Thu, Feb 04, 2021 at 02:37:36PM +0000, Kieran Bingham wrote:
> Utilise the new compiler specific __nodiscard to maintain coding style.
> 
> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---
> 
> Only applicable along with Laurent's [[nodiscard]] series.

I'm open to discussing this, but as replied in another e-mail, I was
envisioning the __nodiscard macro as a temporary fix until we declare
the public API to require C++17. I was annoyed by the C++ [[...]]
attributes initially, but after some time I got used to them and I don't
mind them anymore. Using native language features is usually better from
a readability point of view compared to wrapping them in custom macros,
as the latter needs additional knowledge from the reader.

>  src/android/jpeg/exif.cpp | 2 +-
>  src/android/jpeg/exif.h   | 3 ++-
>  2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/src/android/jpeg/exif.cpp b/src/android/jpeg/exif.cpp
> index fdd46070ba7c..ed995ca13167 100644
> --- a/src/android/jpeg/exif.cpp
> +++ b/src/android/jpeg/exif.cpp
> @@ -515,7 +515,7 @@ std::u16string Exif::utf8ToUtf16(const std::string &str)
>  	return ret;
>  }
>  
> -[[nodiscard]] int Exif::generate()
> +__nodiscard int Exif::generate()
>  {
>  	if (exifData_) {
>  		free(exifData_);
> diff --git a/src/android/jpeg/exif.h b/src/android/jpeg/exif.h
> index b0d614027ede..67dbd20524d8 100644
> --- a/src/android/jpeg/exif.h
> +++ b/src/android/jpeg/exif.h
> @@ -13,6 +13,7 @@
>  
>  #include <libexif/exif-data.h>
>  
> +#include <libcamera/compiler.h>
>  #include <libcamera/geometry.h>
>  #include <libcamera/span.h>
>  
> @@ -75,7 +76,7 @@ public:
>  	void setWhiteBalance(WhiteBalance wb);
>  
>  	libcamera::Span<const uint8_t> data() const { return { exifData_, size_ }; }
> -	[[nodiscard]] int generate();
> +	__nodiscard int generate();
>  
>  private:
>  	ExifEntry *createEntry(ExifIfd ifd, ExifTag tag);

-- 
Regards,

Laurent Pinchart