[libcamera-devel] [simple-cam PATCH 0/4] simple-cam: Update to latest API usage

[Laurent Pinchart]

Hi Kieran,

On Thu, Sep 24, 2020 at 03:47:25PM +0100, Kieran Bingham wrote:
> On 24/09/2020 12:44, Laurent Pinchart wrote:
> > On Thu, Sep 24, 2020 at 09:52:11AM +0100, Kieran Bingham wrote:
> >> On 24/09/2020 04:14, Laurent Pinchart wrote:
> >>> On Wed, Sep 23, 2020 at 05:44:08PM +0100, Kieran Bingham wrote:
> >>>> The simple-cam app needs to be updated with a few API updates to work on
> >>>> the latest libcamera builds.
> >>>>
> >>>> This is based on the code at https://github.com/kbingham/simple-cam
> >>>> though I hope to move this to a more official location soon.
> >>>
> >>> For the whole series,
> >>>
> >>> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> >>>
> >>> It would be interesting to test-compile simple-cam when libcamera gains
> >>> new commits. It can probably wait until libcamera itself gets CI though
> >>> :-)
> >>
> >> This is something I've been working on.
> >>
> >> There are two options, an easy way and a hard way (to do this without
> >> installing the library on each build).
> >>
> >> The hard way (which is of course what was recommended in #meson) is to
> >> provide a meson wrap for libcamera, so that it can be a subproject to
> >> simple-cam. This means if libcamera is not found as a dependency it will
> >> clone libcamera, build it - and automatically link against it statically.
> >>
> >> It doesn't work - due to faults in our set up of the build system and
> >> incorrect usage of things like meson.build_root() and meson.source_root().
> > 
> > Patches are welcome :-)
> 
> Sure - they're already on my todo list from yesterday ;-)
> 
> >> My conversation led to one of the meson devs deciding to mark those as
> >> deprecated :
> >>  (See https://github.com/mesonbuild/meson/pull/7772)
> >>
> >> Anyway, the easy and quick way - is that meson creates a pkg-config
> >> '-uninstalled' location at $BUILD/meson-uninstalled ... and it's really
> >> easy to build an app against an uninstalled library by pointing
> >> PKG_CONFIG_DIR=$BUILD/meson-uninstalled
> 
> Ahem, s/PKG_CONFIG_DIR/PKG_CONFIG_PATH/
> 
> >> So that's a really quick and effective way of also compiling the
> >> 'external' simple-cam against a 'just built' libcamera.
> > 
> > From a build server point of view, I thought the builder could get the
> > latest libcamera master branch, build it, and install it. Why would we
> > need an "uninstalled" location ?
> 
> Hrm, my original answer here was 'because you need to be root to
> install' ... but that's not correct. You can install to a non-root owned
> location (and then make sure the library is on the PKG_CONFIG_PATH...)
> 
> So that's also an option ... and also validates the install procedures.

If the build of simple-cam was automated on a build server, I would
assume it would happen in a container, so we can install anything in any
way we want :-)

> >> I'm adding that to my daily builder, (the one that also does a
> >> coverity-scan build, and a full matrix build of all compilers on my
> >> laptop) - so I'll know as soon as there is breakage.
> >>
> >> And indeed, sometime we'll move this to a more fully handled CI system too.
> >>
> >> Anyway, thanks for the review, I'll push these patches to my repo.
> >>
> >>>> Kieran Bingham (4):
> >>>>   simple-cam: Use the new BufferMap interface
> >>>>   simple-cam: Use a const stream
> >>>>   meson: Remove incorrect default
> >>>>   meson: Update to C++17
> >>>>
> >>>>  meson.build    | 3 +--
> >>>>  simple-cam.cpp | 4 ++--
> >>>>  2 files changed, 3 insertions(+), 4 deletions(-)

-- 
Regards,

Laurent Pinchart