[RFC PATCH v1] libcamera: controls: ControlInfo: Ensure types match

[Barnabás Pőcze]

Hi


2025. február 13., csütörtök 11:57 keltezéssel, Kieran Bingham <kieran.bingham at ideasonboard.com> írta:

> Quoting Barnabás Pőcze (2025-01-28 12:13:55)
> > It is expected that the min/max/default/etc. values in a `ControlInfo`
> > have the same type. So add assertions to check that.
> >
> 
> This patch looks like a very good addition, which could have helped
> catch the issue Naush faced yesterday
> (https://patchwork.libcamera.org/patch/22778/)
> 
> Is there anyway we can make this a compile time assertion instead of a
> runtime check?

I think it is definitely possible, at least to some degree. But that would be an
appreciably more intrusive change.


Regards,
Barnabás Pőcze


> 
> --
> Kieran
> 
> 
> > Signed-off-by: Barnabás Pőcze <pobrn at protonmail.com>
> > ---
> >  src/libcamera/controls.cpp | 22 +++++++++++++++++++++-
> >  1 file changed, 21 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/libcamera/controls.cpp b/src/libcamera/controls.cpp
> > index 70f6f6092..07f276b35 100644
> > --- a/src/libcamera/controls.cpp
> > +++ b/src/libcamera/controls.cpp
> > @@ -580,6 +580,19 @@ ControlId::ControlId(unsigned int id, const std::string &name,
> >   * \brief The Control template type T
> >   */
> >
> > +namespace {
> > +
> > +bool sameShape(const ControlValue &a, const ControlValue &b)
> > +{
> > +       /**
> > +        * \todo This is a best effort approach. Without the `ControlId`
> > +        * there is no way to check if the sizes of fixed size arrays match.
> > +        */
> > +       return a.type() == b.type() && a.isArray() == b.isArray();
> > +}
> > +
> > +}
> > +
> >  /**
> >   * \class ControlInfo
> >   * \brief Describe the limits of valid values for a Control
> > @@ -601,6 +614,7 @@ ControlInfo::ControlInfo(const ControlValue &min,
> >                          const ControlValue &def)
> >         : min_(min), max_(max), def_(def)
> >  {
> > +       ASSERT(sameShape(min_, max_) && (def_.isNone() || sameShape(max_, def_)));
> >  }
> >
> >  /**
> > @@ -616,13 +630,19 @@ ControlInfo::ControlInfo(const ControlValue &min,
> >  ControlInfo::ControlInfo(Span<const ControlValue> values,
> >                          const ControlValue &def)
> >  {
> > +       ASSERT(!values.empty());
> > +
> >         min_ = values.front();
> >         max_ = values.back();
> >         def_ = !def.isNone() ? def : values.front();
> >
> > +       ASSERT(sameShape(min_, max_) && sameShape(max_, def_));
> > +
> >         values_.reserve(values.size());
> > -       for (const ControlValue &value : values)
> > +       for (const ControlValue &value : values) {
> > +               ASSERT(sameShape(def_, value));
> >                 values_.push_back(value);
> > +       }
> >  }
> >
> >  /**
> > --
> > 2.48.1
> >
> >
>