Re: utility functions for handling Distinguished Names

[Graham B. <gb...@po...>]

On Wed, Apr 24, 2002 at 06:45:31PM +0200, Norbert Klasen wrote:
> Hi Graham,
> I put the #xxxx issue in a separate mail.
> 
> >> --- Util.pm-0.25_01	Tue Apr 23 20:35:04 2002
> >> +++ Util.pm	Tue Apr 23 21:16:17 2002
> >> @@ -231,8 +231,8 @@
> >
> >>  sub canonical_dn($%) {
> >> -  my $dn = shift or return '';
> >> +  my $dn = shift;
> >> +  return $dn unless $dn; # empty DN or undef
> >
> >  $dn = "0" ?
> 
> This is another case to consider.
> 
> > This should be  return $dn unless $dn and length $dn;
>
> return $dn if $dn eq '' || !defined $dn ; # empty DN or undef
> 
> This handles undef, '' and "0" (leads to an error later).

Yes, mine needs a defined added, which will make it -w clean too.

> > Does it really make sense for ldap_explode_dn todo the reverse ?
> 
> I added a reverse option to ldap_explode_dn and though it would be a good 
> idea to use it from canonical_dn as well. Am I missing something?

I am just not sure what the benefit of having reverse in ldap_explode_dn
is ? It was only ever in canonical_dn to make sorting DNs easier.

It anywan want the output of explode in reverse, then they can call reverse.

> >>  sub ldap_explode_dn($%) {
> >> -  my $dn = shift or return;
> >> +  my @emptydn = (); #empty DN array for scalar context
> >> +  my $dn = shift;
> >> +  return wantarray ? [] : \@emptydn if $dn eq '';
> >
> > This does not make sense. You are returning a scalar ref
> > when wantarray is true. Did you mean
> >
> >   return wantarray ? () : [] if $dn eq '';
> 
> I'm not that familar with these elements of Perl so it tell you what a I 
> actually had in mind: The return value of ldap_explode_dn should give the 
> user an indication, whether an invalid DN was passed in. The problem is now 
> that the (valid) empty DN '' explodes to an empty array. In the scalar 
> context one can return undef or a reference to an empty array but I don't 
> know to express this in list context.

Yup this is a common problem with context sensetive subs. If the user
cares about it they need to call it in a scalar context.

> >>    my %opt = @_;
> >>
> >>    my (@dn, %rdn);
> >> +  $dn =~ s/^<(.*)>$/$1/; #remove brackets
> >
> > why ? where is it defined that DNs have <> brackets ?
> 
> There is a test case <UID=jsmith,O=example,C=US> in the ldapbis document. I 
> don't know where such could be defined. Kurt?

OK, fine.

Graham.