[PATCH] libcamera: meson: Fix libyuv detection

[Barnabás Pőcze]

Hi


2025. január 14., kedd 22:24 keltezéssel, Kieran Bingham <kieran.bingham at ideasonboard.com> írta:

> Quoting Kieran Bingham (2025-01-14 21:19:35)
> > From: Dylan Aïssi <daissi at debian.org>
> >
> > We already fall back to a subproject to support the libyuv package when
> > it can not be discovered through the usual dependency() mechanism.
> >
> > Unfortunately libyuv may be packaged without any corresponding
> > pkg-config support as can be seen at [0], so further extend the
> > dependency search by using an explicit cc.find_library() call.
> >
> > [0] https://packages.debian.org/bookworm/amd64/libyuv-dev/filelist
> >
> > Signed-off-by: Dylan Aïssi <dylan.aissi at collabora.com>
> 
> I've posted this patch on Dylan's behalf from
> https://salsa.debian.org/multimedia-team/libcamera/-/commit/685482827a0e6fe5dfe19778e633ab95b703cef4
> though I have reworded the commit message and comment inline, but the
> core functional change is direct from Dylan's patch...
> 
> 
> On Ubuntu 22.04.5 LTS:
> 
> $ sudo apt install libyuv-dev
> 
> ...
> libcamera$ meson setup ...
> ...
> Found pkg-config: YES (/usr/bin/pkg-config) 0.29.2
> Found CMake: /usr/bin/cmake (3.22.1)
> Run-time dependency libyuv found: NO (tried pkgconfig and cmake)
> Library yuv found: YES
> Library atomic found: YES
> ...
> 
> (Based on the second Library yuv found: YES)
> 
> Tested-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

This is the change I have locally to achieve the same:

diff --git a/src/meson.build b/src/meson.build
index 76198e953..8cb4af61a 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -30,7 +30,20 @@ endif
 # libyuv, used by the Android adaptation layer and the virtual pipeline handler.
 # Fallback to a subproject if libyuv isn't found, as it's typically not provided
 # by distributions.
-libyuv_dep = dependency('libyuv', required : false)
+
+if not get_option('force_fallback_for').contains('libyuv')
+    libyuv_dep = dependency('libyuv', required : false)
+
+    if not libyuv_dep.found()
+        libyuv_dep = cxx.find_library(
+            'yuv',
+            required : false,
+            has_headers : 'libyuv.h',
+        )
+    endif
+else
+    libyuv_dep = dependency('', required : false)
+endif
 
 if (pipelines.contains('virtual') or get_option('android').allowed()) and \
    not libyuv_dep.found()

This has two advantages in my opinion:
  * the `force_fallback_for=libyuv` meson option works;
  * the presence of at least `libyuv.h` is checked
    (I imagine this may be relevant for distributions where the development files
     are placed in different packages).

`meson` has recently added experimental cmake wraps:
https://mesonbuild.com/Wrap-dependency-system-manual.html#cmake-wraps
I think this could make the dependency lookup simpler, but it is probably too new.

Or potentially `libyuv` could be added to the meson wrapdb,
which could also enable some simplification.


Regards,
Barnabás Pőcze


> 
> > Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> > ---
> >  src/meson.build | 11 ++++++++---
> >  1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/src/meson.build b/src/meson.build
> > index 76198e9535db..0a9cdff8e7dc 100644
> > --- a/src/meson.build
> > +++ b/src/meson.build
> > @@ -27,10 +27,15 @@ else
> >      ipa_sign_module = false
> >  endif
> >
> > -# libyuv, used by the Android adaptation layer and the virtual pipeline handler.
> > -# Fallback to a subproject if libyuv isn't found, as it's typically not provided
> > -# by distributions.
> > +# libyuv, used by the Android adaptation layer and the virtual pipeline
> > +# handler. Fallback to a subproject if libyuv isn't found, as it's typically
> > +# not provided by distributions. Where libyuv is provided by a distribution, it
> > +# may not always supply a pkg-config implementation, requiring cc.find_library()
> > +# to search for it.
> >  libyuv_dep = dependency('libyuv', required : false)
> > +if not libyuv_dep.found()
> > +    libyuv_dep = cc.find_library('yuv', required: false)
> > +endif
> >
> >  if (pipelines.contains('virtual') or get_option('android').allowed()) and \
> >     not libyuv_dep.found()
> > --
> > 2.47.1
> >
>