[libcamera-devel] [RFC PATCH 10/10] libcamera: framebuffer: Add assertion to detect offset is unfilled

[Laurent Pinchart]

Hi Hiro,

On Fri, Aug 20, 2021 at 08:18:47PM +0900, Hirokazu Honda wrote:
> On Wed, Aug 18, 2021 at 10:42 AM Laurent Pinchart wrote:
> > On Mon, Aug 16, 2021 at 01:31:38PM +0900, Hirokazu Honda wrote:
> > > The offset variable is introduced to FrameBuffer::Plane. In order to
> > > detect that the plane is used while the offset is not set, this adds
> > > the assertion to FrameBuffer::planes(). It should be removed in the
> > > future.
> > >
> > > Signed-off-by: Hirokazu Honda <hiroh at chromium.org>
> > > ---
> > >  include/libcamera/framebuffer.h | 13 +++++++++++--
> > >  1 file changed, 11 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/include/libcamera/framebuffer.h b/include/libcamera/framebuffer.h
> > > index 5de3c744..79541557 100644
> > > --- a/include/libcamera/framebuffer.h
> > > +++ b/include/libcamera/framebuffer.h
> > > @@ -7,6 +7,8 @@
> > >  #ifndef __LIBCAMERA_FRAMEBUFFER_H__
> > >  #define __LIBCAMERA_FRAMEBUFFER_H__
> > >
> > > +#include <assert.h>
> > > +#include <limits>
> > >  #include <stdint.h>
> > >  #include <vector>
> > >
> > > @@ -41,14 +43,21 @@ class FrameBuffer final : public Extensible
> > >
> > >  public:
> > >       struct Plane {
> > > +             static constexpr unsigned int kInvalidOffset = std::numeric_limits<unsigned int>::max();
> >
> > Maybe a blank line here ?
> >
> > This also generates a doxygen warning as kInvalidOffset is not
> > documented. As it's not meant to be used by anyone else than the code
> > below, this could be addressed by making the constant private.
> >
> 
> I couldn't move it to private because it is used in the below assert.
> I document the variable.
> 
> > >               FileDescriptor fd;
> > > -             unsigned int offset;
> > > +             unsigned int offset = kInvalidOffset;
> > >               unsigned int length;
> > >       };
> > >
> > >       FrameBuffer(const std::vector<Plane> &planes, unsigned int cookie = 0);
> > >
> > > -     const std::vector<Plane> &planes() const { return planes_; }
> > > +     const std::vector<Plane> &planes() const
> > > +     {
> > > +             /* \todo remove this assert. */
> >
> > When do you foresee this being removed ?
> 
> Maybe for a month. Just an arbitrary foresee.

Then let's write

		/* \todo Remove the assertions after sufficient testing */

> > > +             for (const auto &plane : planes_)
> > > +                     assert(plane.offset != Plane::kInvalidOffset);
> > > +             return planes_;
> > > +     }
> > >
> > >       Request *request() const;
> > >       const FrameMetadata &metadata() const { return metadata_; }

-- 
Regards,

Laurent Pinchart