Re: [gentoo-dev] [PATCH 2/2] Use new multilib flags in autotools-multilib.

[Alexis Ballier]

On Sat, 26 Jan 2013 16:06:35 +0100
Michał Górny <mgorny@g.o> wrote:

> On Sat, 26 Jan 2013 11:51:22 -0300
> Alexis Ballier <aballier@g.o> wrote:
>
> > On Sat, 26 Jan 2013 13:11:41 +0100
> > Michał Górny <mgorny@g.o> wrote:
> >
> > > On Wed, 23 Jan 2013 21:40:13 -0300
> > > Alexis Ballier <aballier@g.o> wrote:
> > >
> > > > On Thu, 24 Jan 2013 00:23:57 +0100
> > > > Michał Górny <mgorny@g.o> wrote:
> > > >
> > > > > This is mostly a proof-of-concept. If approved, I will work on
> > > > > moving the code into a separate eclass, possibly named
> > > > > 'multilib-build' ;). ---
> > > > >  gx86/eclass/autotools-multilib.eclass | 24
> > > > > +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3
> > > > > deletions(-)
> > > > >
> > > > > diff --git a/gx86/eclass/autotools-multilib.eclass
> > > > > b/gx86/eclass/autotools-multilib.eclass index 7c8697a..eef7bcc
> > > > > 100644 --- a/gx86/eclass/autotools-multilib.eclass
> > > > > +++ b/gx86/eclass/autotools-multilib.eclass
> > > > > @@ -32,7 +32,23 @@ inherit autotools-utils multilib
> > > > >
> > > > >  EXPORT_FUNCTIONS src_configure src_compile src_test
> > > > > src_install
> > > > > -IUSE=multilib
> > > > > +# Declare all of them, profiles will control their
> > > > > visibility. +IUSE='abi_x86_32 abi_x86_64'
> > > > > +
> > > > > +# @FUNCTION: _autotools-multilib_get_enabled_abis
> > > > > +# @DESCRIPTION:
> > > > > +# Get the list of enabled ABIs. The returned names are
> > > > > suitable for use +# with multilib.eclass.
> > > > > +#
> > > > > +# If multilib is not enabled or not supported, returns an
> > > > > empty list. +
> > > > > +	debug-print-function ${FUNCNAME} "${@}"
> > > > > +
> > > > > +	if use amd64; then
> > > > > +		use abi_x86_64 && echo amd64
> > > > > +		use abi_x86_32 && echo x86
> > > > > +	fi
> > > > > +}
> > > >
> > > > I would rather iterate over a variable than hardcoding and
> > > > duplicating it here:
> > > >
> > > > MULTILIB_ABIS='abi_x86_32:x86 abi_x86_64:amd64'
> > > > IUSE=""
> > > > for i in $MULTILIB_ABIS ; do
> > > >    IUSE+=" ${i%:*}"
> > > > done
> > > >
> > > > _autotools-multilib_get_enabled_abis() {
> > > >    for i in $MULTILIB_ABIS ; do
> > > >       use ${i%:*} && echo ${i#*:}
> > > >    done
> > > > }
> > >
> > > What are the advantages? I feel like the explicit solution is much
> > > more readable and obvious at the first glance.
> >
> > yes it is more readable but IMHO it's better to avoid to have to
> > touch multiple places when adding a new ABI: you only have to
> > document that adding a new ABI consists simply in adding it to this
> > list (and document the useflag) instead of 'add the useflag, add
> > support for it to function foo and bar, etc.'
> > your call in the end, but I fear not trying to separate code from
> > data could make the eclass harder to maintain.
>
> Ok, separating data from code seems a valid concern. However, I feel
> like this is not really clear concept in bash, and the intent is that
> the ABI list will be used only in that function.

makes sense; the foo:bar trick is what I've came up in trying to emulate
python dictionaries :)


> > also, IMHO you shouldn't use arch to guess what useflag to check or
> > not: they'll all be in IUSE in the end and the profiles should be
> > the one deciding what to mask or not (which you'll have to do
> > anyway), not the eclass.
>
> Well, I think I've stated that already. That 'use foo &&' is just
> an optimization hack -- to not check all the irrelevant flags all
> the time.

I'm not sure 'optimizations' are relevant when we're going to build
twice the package here :P
Also, # of arches is about the same order of magnitude than # of abis,
thus checking # of arches time use $arch or # of abis times use $abi is,
in the end, comparable while checking arch adds the constraint that
the eclass and the profiles have to be in sync.

Alexis.