Re: [dpdk-dev] [PATCH] usertools: fix pmdinfo parsing

[Stephen Hemminger <stephen@networkplumber.org>]

On Tue, 3 Nov 2020 21:20:43 +0100
David Marchand <david.marchand@redhat.com> wrote:

> On Tue, Nov 3, 2020 at 8:27 PM Robin Jarry <robin.jarry@6wind.com> wrote:
> > 2020-11-03, David Marchand:  
> > > This script was using the librte_pmd prefix has a filter to follow  
> 
> as*
> 
> > > DT_NEEDED entries.
> > > Now that we changed the driver names, update this heuristic with an
> > > explicit list of device classes.
> > >
> > > Fixes: a20b2c01a7a1 ("build: standardize component names and defines")
> > >
> > > Signed-off-by: David Marchand <david.marchand@redhat.com>
> > > ---
> > >  usertools/dpdk-pmdinfo.py | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/usertools/dpdk-pmdinfo.py b/usertools/dpdk-pmdinfo.py
> > > index 1661982791..687a9fd032 100755
> > > --- a/usertools/dpdk-pmdinfo.py
> > > +++ b/usertools/dpdk-pmdinfo.py
> > > @@ -450,7 +450,10 @@ def process_dt_needed_entries(self):
> > >          for tag in dynsec.iter_tags():
> > >              # pyelftools may return byte-strings, force decode them
> > >              if force_unicode(tag.entry.d_tag) == 'DT_NEEDED':
> > > -                if 'librte_pmd' in force_unicode(tag.needed):
> > > +                words = force_unicode(tag.needed).split('_')
> > > +                if words and len(words) >= 3 and words[0] == 'librte' and \
> > > +                   words[1] in ['baseband', 'compress', 'crypto', 'event',
> > > +                                'net', 'raw', 'regex', 'vdpa']:  
> >
> > This code is already ugly and I don't have much better to suggest...  
> 
> Less ugly with a regular expression?
> 
> if re.match(r"^librte_(baseband|compress|crypto|event|net|raw|regex|vdpa)_",
>             force_unicode(tag.needed)):
> 
> 

I prefer the list approach, much less error prone.
The code would read better if the list of drivers was in a variable
instead of a long line of code and the string processing was done separate from
the test.
Something like
                   drivers = ['baseband', 'compress'...
                   prefix = 'librte_pmd'
		   name = force_unicode(tag.needed)
                   if name.startswith(prefix):
                       suffix = name[len(prefix):]
                       if suffx in drivers: