[libcamera-devel] [PATCH v2] cam: file_sink: Fixes following errors with gcc-13

[Kieran Bingham]

Quoting Eric Curtin via libcamera-devel (2023-02-14 13:34:11)
> On Tue, 14 Feb 2023 at 13:24, Laurent Pinchart
> <laurent.pinchart at ideasonboard.com> wrote:
> >
> > Hi Eric,
> >
> > (CC'ing Barnabás)
> >
> > Thank you for the patch.
> >
> > On Tue, Feb 14, 2023 at 12:14:49PM +0000, Eric Curtin via libcamera-devel wrote:
> > > ../git/src/cam/file_sink.cpp:92:45: error: possibly dangling reference to a temporary [-Werror=dangling-reference]
> > >    92 |                 const FrameMetadata::Plane &meta = buffer->metadata().planes()[i];
> > >       |                                             ^~~~
> > > ../git/src/cam/file_sink.cpp:92:81: note: the temporary was destroyed at the end of the full expression '(& buffer->libcamera::FrameBuffer::metadata())->libcamera::FrameMetadata::planes().libcamera::Span<const libcamera::FrameMetadata::Plane>::operator[](i)'
> > >    92 |                 const FrameMetadata::Plane &meta = buffer->metadata().planes()[i];
> > >       |                                                                                 ^
> > > cc1plus: all warnings being treated as errors
> >
> > This seems to be a false positive from an unreleased gcc version. Could
> > you report the issue to upstream gcc ? I'd like to get it fixed if it's
> 
> Reported here:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107532
> 
> I added another poke.
> 
> > indeed a false positive, or at least get confirmation from them that
> > they won't fix it.
> >

Let's add this here then:

Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107532

> > > Co-developed-by: Khem Raj <raj.khem at gmail.com>
> > > Signed-off-by: Eric Curtin <ecurtin at redhat.com>
> > > ---
> > > Changes in v2:
> > >
> > > - Added const
> > > - Made patch mergeable by accounting for new directory structure
> > > ---
> > >  src/apps/cam/file_sink.cpp | 9 ++++-----
> > >  1 file changed, 4 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/src/apps/cam/file_sink.cpp b/src/apps/cam/file_sink.cpp
> > > index b32aad24..d41569c9 100644
> > > --- a/src/apps/cam/file_sink.cpp
> > > +++ b/src/apps/cam/file_sink.cpp
> > > @@ -114,13 +114,12 @@ void FileSink::writeBuffer(const Stream *stream, FrameBuffer *buffer,
> > >       }
> > >
> > >       for (unsigned int i = 0; i < buffer->planes().size(); ++i) {

I'd be tempted to add some sort of explainer here in a comment, but
maybe that's overkill if the bug does get fixed before GCC-13 is
released...?

> > > -             const FrameMetadata::Plane &meta = buffer->metadata().planes()[i];
> > > -
> > > +             const unsigned int bytesused = buffer->metadata().planes()[i].bytesused;
> > >               Span<uint8_t> data = image->data(i);
> > > -             unsigned int length = std::min<unsigned int>(meta.bytesused, data.size());
> > > +             const unsigned int length = std::min<unsigned int>(bytesused, data.size());
> > >
> > > -             if (meta.bytesused > data.size())
> > > -                     std::cerr << "payload size " << meta.bytesused
> > > +             if (bytesused > data.size())
> > > +                     std::cerr << "payload size " << bytesused

Otherwise, the change itself seems fair, and does the 'same thing'...
so:


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

> > >                                 << " larger than plane size " << data.size()
> > >                                 << std::endl;
> > >
> >
> > --
> > Regards,
> >
> > Laurent Pinchart
> >
>