Le vendredi 4 décembre 2020, 19:02:09 CET James Bottomley a écrit :
> On Fri, 2020-12-04 at 18:07 +0100, Ard Biesheuvel wrote:
> > On Fri, 4 Dec 2020 at 18:06, <laniel_francis@xxxxxxxxxxxxxxxxxxx>
> >
> > wrote:
> > > From: Francis Laniel <laniel_francis@xxxxxxxxxxxxxxxxxxx>
> > >
> > > The two functions indicates if a string begins with a given prefix.
> > > The only difference is that strstarts() returns a bool while
> > > str_has_prefix()
> > > returns the length of the prefix if the string begins with it or 0
> > > otherwise.
> >
> > Why?
>
> I think I can answer that. If the conversion were done properly (which
> it's not) you could get rid of the double strings in the code which are
> error prone if you update one and forget another. This gives a good
> example: 3d739c1f6156 ("tracing: Use the return of str_has_prefix() to
> remove open coded numbers"). so in your code you'd replace things like
>
> if (strstarts(option, "rgb")) {
> option += strlen("rgb");
> ...
>
> with
>
> len = str_has_prefix(option, "rgb");
> if (len) {
> option += len
> ...
The proposed changes were a bit mechanical and I did not think about using the
returned value in the way you proposed.
This a good idea though, so I can modify my patches to include this and send a
v2!
> Obviously you also have cases where strstart is used as a boolean with
> no need to know the length ... I think there's no value to converting
> those.
For the v2, should I only change cases where using str_has_prefix() brings a
benefit over strstarts() or all the cases?
> James
