[libcamera-devel] [RFC PATCH 1/8] meson: Simplify pkg_mod.generate

[Laurent Pinchart]

On Tue, Dec 01, 2020 at 05:01:46PM +0000, Kieran Bingham wrote:
> Hi Laurent,
> 
> On 01/12/2020 16:58, Laurent Pinchart wrote:
> > Hi Kieran,
> > 
> > On Tue, Dec 01, 2020 at 04:56:56PM +0000, Kieran Bingham wrote:
> >> On 01/12/2020 16:50, Laurent Pinchart wrote:
> >>> On Mon, Nov 23, 2020 at 04:43:12PM +0000, Kieran Bingham wrote:
> >>>> Later versions of meson allow for the first positional argument to
> >>>> specificy the defaults.  Specify the libcamera library as the first
> >>>> argument, and remove the filebase.
> >>>>
> >>>> Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> >>>> ---
> >>>>  meson.build | 3 +--
> >>>>  1 file changed, 1 insertion(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/meson.build b/meson.build
> >>>> index 55cf36e15f57..ced4afa7d726 100644
> >>>> --- a/meson.build
> >>>> +++ b/meson.build
> >>>> @@ -146,10 +146,9 @@ run_command('ln', '-fsT', meson.source_root(),
> >>>>  configure_file(output : 'config.h', configuration : config_h)
> >>>>  
> >>>>  pkg_mod = import('pkgconfig')
> >>>> -pkg_mod.generate(libraries : libcamera,
> >>>> +pkg_mod.generate(libcamera,
> >>>>                   version : '1.0',
> >>>>                   name : 'libcamera',
> >>>> -                 filebase : 'camera',
> >>>>                   description : 'Complex Camera Support Library',
> >>>>                   subdirs : 'libcamera')
> >>>>  
> >>>
> >>> The documentation states
> >>>
> >>> Since 0.46 a StaticLibrary or SharedLibrary object can optionally be
> >>> passed as first positional argument. If one is provided a default value
> >>> will be provided for all required fields of the pc file:
> >>>
> >>> - install_dir is set to pkgconfig folder in the same location than the
> >>>   provided library.
> >>> - description is set to the project's name followed by the library's
> >>>   name.
> >>> - name is set to the library's name.
> >>>
> >>>
> >>> Is it the "name" argument that can be dropped, not "filebase" ? filebase
> >>> seems to default to name, so it would be set to "libcamera", not
> >>> "camera". If we drop the name argument then name will default to the
> >>> shared library name, which is "camera", and filebase will then default
> >>> to name. There thus seems to be a change of behaviour, which should be
> >>> documented in the commit message (and verified to ensure it's correct).
> >>
> >>
> >> I'll have to check, but this was a patch I had stuck around for ages,
> >> which I created upon a recommendation from one of the meson devs.
> >>
> >> I haven't seen any change in behaviour, but I'll double check again
> >> later, meanwhile: an install from this build seems to show everything
> >> still correctly named 'libcamera' ...
> >>
> >> /tmp/libcamera-build-prefix/usr/share/libcamera
> >> /tmp/libcamera-build-prefix/usr/share/doc/libcamera-0.0.11
> >> /tmp/libcamera-build-prefix/usr/lib/x86_64-linux-gnu/libcamera.so
> >> /tmp/libcamera-build-prefix/usr/include/libcamera/libcamera/version.h
> > 
> > I expect this patch to only affect the .pc file generation :-) Could you
> > diff its contents, and check if its name changes ?
> 
> diff
> /tmp/libcamera-build-prefix/usr/lib/x86_64-linux-gnu/pkgconfig/libcamera.pc
> /usr/lib/x86_64-linux-gnu/pkgconfig/libcamera.pc
> 
> <blank> ;-)

That's strange, here I have

diff -Nur a/usr/local/lib64/pkgconfig/camera.pc b/usr/local/lib64/pkgconfig/camera.pc
--- a/usr/local/lib64/pkgconfig/camera.pc       2020-12-01 17:37:07.077026434 +0200
+++ b/usr/local/lib64/pkgconfig/camera.pc       1970-01-01 02:00:00.000000000 +0200
@@ -1,9 +0,0 @@
-prefix=/usr/local
-libdir=${prefix}/lib64
-includedir=${prefix}/include
-
-Name: libcamera
-Description: Complex Camera Support Library
-Version: 1.0
-Libs: -L${libdir} -lcamera
-Cflags: -I${includedir}/libcamera
diff -Nur a/usr/local/lib64/pkgconfig/libcamera.pc b/usr/local/lib64/pkgconfig/libcamera.pc
--- a/usr/local/lib64/pkgconfig/libcamera.pc    1970-01-01 02:00:00.000000000 +0200
+++ b/usr/local/lib64/pkgconfig/libcamera.pc    2020-12-01 19:04:21.415247132 +0200
@@ -0,0 +1,9 @@
+prefix=/usr/local
+libdir=${prefix}/lib64
+includedir=${prefix}/include
+
+Name: libcamera
+Description: Complex Camera Support Library
+Version: 1.0
+Libs: -L${libdir} -lcamera
+Cflags: -I${includedir}/libcamera

Contents are the same, but the .pc file got renamed from camera.pc to
libcamera.pc. No necessarily an issue, but pkg-config will need to be
run with an updated name, requiring an update to simple-cam I believe.

If we additionally drop the name argument, the file name is preserved,
but its contents change to

--- a/usr/local/lib64/pkgconfig/camera.pc	2020-12-01 17:37:07.077026434 +0200
+++ b/usr/local/lib64/pkgconfig/camera.pc	2020-12-01 19:09:47.299260873 +0200
@@ -2,7 +2,7 @@
 libdir=${prefix}/lib64
 includedir=${prefix}/include
 
-Name: libcamera
+Name: camera
 Description: Complex Camera Support Library
 Version: 1.0
 Libs: -L${libdir} -lcamera


I'm not a pkg-config expert so I don't know if we should include the lib
prefix in the file name and/or the Name.

-- 
Regards,

Laurent Pinchart