[OE-core] [PATCH RFC] pixbufcache: Use sceneQueueComplete event to simplify usage

[Richard Purdie]

On Sun, 2014-08-17 at 10:33 +0200, Jacob Kroon wrote:
> On Sat, Aug 2, 2014 at 10:54 AM, Richard Purdie
> <richard.purdie at linuxfoundation.org> wrote:
>         [This is an RFC which depends on a patch to bitbake to
>         operate]
>         
>         Currently, we have a mess of dependencies for pixbufcache and
>         even then
>         it breaks since they might be controlled by PACKAGECONFIG.
>         
>         Instead, this patch proposes an alternative approach where we
>         allow
>         "fixups" from a sceneQueueComplete() event at the end of the
>         setscene
>         process. We signal the need for these using simply stamp
>         files.
>         
>         The one downside is that the processing code needs to be in a
>         global
>         event handler like base.bbclass rather than
>         pixbufcache.bbclass but this
>         is probably a price worth paying to avoid the dependency mess?
>         
>         Signed-off-by: Richard Purdie
>         <richard.purdie at linuxfoundation.org>
>         
> 
> 
> Instead of having the sstate_postinst() touch "needpixbuf", could we
> make it write out the actual script that needs to be executed ?
> 
> Then base.bbclass could iterate over any scripts installed by any
> sstate_postinst() and execute them. At least this would better isolate
> the pixbuf-code to pixbufcache.bbclass, and make the snippet in
> base.bbclass more generic.

It does become trickier to avoid races when writing out that script.
Touching the file is rather easy from a lock perspective :)

Cheers,

Richard