[pacman-dev] [PATCH] Add a utility function to check whether a file exists in the cache

[Anatol Pomozov]

Hi

On Sun, Apr 26, 2020 at 6:07 PM Allan McRae <allan at archlinux.org> wrote:
>
> On 24/4/20 2:41 pm, Anatol Pomozov wrote:
> > It is similar to _alpm_filecache_find() but does not return a
> > dynamically allocated memory to user. Thus the user does not need to
> > free this resource.
> >
> > Signed-off-by: Anatol Pomozov <anatol.pomozov at gmail.com>
> > ---
> >  lib/libalpm/util.c | 14 ++++++++++++++
> >  lib/libalpm/util.h |  2 ++
> >  2 files changed, 16 insertions(+)
> >
> > diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
> > index cb838e43..6307dc14 100644
> > --- a/lib/libalpm/util.c
> > +++ b/lib/libalpm/util.c
> > @@ -834,6 +834,20 @@ char *_alpm_filecache_find(alpm_handle_t *handle, const char *filename)
> >       return NULL;
> >  }
> >
> > +/** Check whether a filename exists in a registered alpm cachedir.
> > + * @param handle the context handle
> > + * @param filename name of file to find
> > + * @return 0 if the filename was not found, 1 otherwise
> > + */
> > +int _alpm_filecache_exists(alpm_handle_t *handle, const char *filename)
> > +{
> > +     int res;
> > +     char *fpath = _alpm_filecache_find(handle, filename);
> > +     res = !!fpath;
>
> Please adjust:
>
> res = (fpath != NULL)
>
> This follows from our style guideline (although not explicitly stated)
>
> 6.  When using strcmp() (or any function that returns 0 on success) in a
>     conditional statement, use != 0 or == 0 and not the negation (!)
>     operator.

Done.

> I'm also assuming that this function will not be used in such a way that
> _alpm_filecache_find will be called again if it exists...

Correct. The added function should not be used in conjunction with
_alpm_filecache_find() like you described.