[pulseaudio-discuss] [PATCH] build-sys: First pass at a meson-ified build system

[Tanu Kaskinen]

On Sun, 2017-12-10 at 12:46 +0530, Arun Raghavan wrote:
> On Sat, 9 Dec 2017, at 10:58 PM, Felipe Sateler wrote:
> > On Sat, Dec 9, 2017 at 2:59 AM, Arun Raghavan <arun at arunraghavan.net>
> > wrote:
> > > (Note: this patch depends on the symdef header removal work from a few
> > > days ago)
> > > 
> > > This is a working implementation of a build with meson. The server,
> > > utils, and most modules build with this, and it is possible to run from
> > > a build tree and play/capture audio on ALSA devices.
> > > 
> > > There are a number of FIXMEs, of course, and a number of features that
> > > need to be enabled (modules, dependencies, installation, etc.), but this
> > > should provide everything we need to get there relatively quickly.
> > > 
> > 
> > This is nice. Build times should be greatly reduced. As a datapoint,
> > you can check how the systemd debian package takes about hallf the
> > time since version 234, when meson was introduced.
> > 
> > https://buildd.debian.org/status/logs.php?pkg=systemd&arch=amd64&suite=sid
> > 
> > > To use this, install meson (distro package, or mesonbuild.com) and run:
> > > 
> > >   $ cd <pulseaudio src dir>
> > >   $ meson <builddir>
> > >   $ ninja -C <builddir>
> > > ---
> > >  meson.build                       | 218 ++++++++++++++++++++++++++++++++++++++
> > >  meson_options.txt                 |  13 +++
> > >  src/daemon/daemon-conf.c          |   4 +
> > >  src/daemon/main.c                 |   9 ++
> > >  src/daemon/meson.build            |  34 ++++++
> > >  src/meson.build                   | 194 +++++++++++++++++++++++++++++++++
> > >  src/modules/alsa/meson.build      |  31 ++++++
> > >  src/modules/meson.build           | 127 ++++++++++++++++++++++
> > >  src/modules/module-role-cork.c    |   2 +-
> > >  src/modules/module-role-ducking.c |   2 +-
> > >  src/pulse/meson.build             |  73 +++++++++++++
> > >  src/pulsecore/meson.build         | 170 +++++++++++++++++++++++++++++
> > >  src/pulsecore/module.c            |   4 +
> > >  src/utils/meson.build             |  67 ++++++++++++
> > >  14 files changed, 946 insertions(+), 2 deletions(-)
> > >  create mode 100644 meson.build
> > >  create mode 100644 meson_options.txt
> > >  create mode 100644 src/daemon/meson.build
> > >  create mode 100644 src/meson.build
> > >  create mode 100644 src/modules/alsa/meson.build
> > >  create mode 100644 src/modules/meson.build
> > >  create mode 100644 src/pulse/meson.build
> > >  create mode 100644 src/pulsecore/meson.build
> > >  create mode 100644 src/utils/meson.build
> > > 
> > > diff --git a/meson.build b/meson.build
> > > new file mode 100644
> > > index 000000000..1b00dc1e0
> > > --- /dev/null
> > > +++ b/meson.build
> > > @@ -0,0 +1,218 @@
> > > +project('pulseaudio', 'c', 'cpp',
> > > +        version : '10.99.1',
> > > +        meson_version : '>= 0.31.0',
> > > +        default_options : [ 'c_std=gnu11', 'cpp_std=c++11' ]
> > > +        )
> > > +
> > > +pa_version = meson.project_version()
> > > +version_split = pa_version.split('.')
> > > +pa_version_major = version_split[0]
> > > +pa_version_minor = version_split[1]
> > > +pa_version_micro = version_split[2]
> > > +pa_version_major_minor = pa_version_major + '.' + pa_version_minor
> > > +
> > > +pa_api_version = 12
> > > +pa_protocol_version = 31
> > > +
> > > +apiversion = '1.0'
> > > +soversion = 0
> > > +# maintaining compatibility with the previous libtool versioning
> > > +# current = minor * 100 + micro
> > > +libversion = '@0 at .@1 at .0'.format(soversion, pa_version_minor.to_int() * 100 + pa_version_micro.to_int())
> > 
> > This gives 0.9901.0 instead of 0.20.2
> 
> Yeah, we need to fix it up to do the right thing. Let's fix this in a
> subsequent patch.
> 
> My intention is to not have this be complete, but to have it land in
> some usable state and incrementally make it better. I expect we'll be
> supporting autofoo + meson for a while until there is parity between the
> two (across platforms).

Do you have a list of what remains to be done? Clearly not everything
is marked with FIXMEs.

> > > +if cc.has_function('SYS_memfd_create', prefix : '#include <sys/syscall.h>')
> > > +  cdata.set('HAVE_MEMFD', 1)
> > > +endif
> > 
> > configure has the option to enable or disable this. This meson script
> > autodetects only. I think the ability to explicitly disable/enable
> > (and error out if dependencies are not found) is nice to keep when
> > moving to meson. That is, this should become something like:
> > 
> > want_memfd = get_option('memfd')
> > if want_memfd != 'false'
> >   has_memfd = cc.has_function('SYS_memfd_create', prefix : '#include
> > <sys/syscall.h>')
> >   if has_memfd
> >     cdata.set('HAVE_MEMFD', 1)
> >   elif want_memfd == 'true'
> >     error('Memfd was requested but it was not found')
> >   endif
> > endif
> > 
> > plus a meson_options.txt:
> > 
> > option('memfd', type: 'combo', choices: ['auto', 'true', 'false'],
> >   description: 'Enable Linux memfd shared memory')
> > 
> > This applies to a lot of the checks.
> 
> This may be a hard, but in the long run, I actually would like to remove
> automagic dependencies. This makes builds more consistent, and removes a
> lot of (imo unnecessary) if/else-ery.
> 
> So we would have want_memfd on by default (maybe conditional on OS ==
> Linux), and then you could disable it at configure time if you don't
> want it.

That kind of plan seems likely to cause unnecessary hassle for
people... I think enabling features automatically based on what's
available is a good approach.

-- 
Tanu

https://www.patreon.com/tanuk