Re: [PATCH] xdiff: rename "struct group" to "struct xdlgroup"

> Commit e8adf23 (xdl_change_compact(): introduce the concept
> of a change group, 2016-08-22) added a "struct group" type
> to xdiff/xdiffi.c. But the POSIX system header "grp.h"
> already defines "struct group" (it is part of the getgrnam
> interface). This happens to work because the new type is
> local to xdiffi.c, and the xdiff code includes a relatively
> small set of system headers. But it will break compilation
> if xdiff ever switches to using git-compat-util.h.  It can
> also probably cause confusion with tools that look at the
> whole code base, like coccinelle or ctags.
>
> Let's resolve by giving the xdiff variant a scoped name,
> which is closer to other xdiff types anyway (e.g.,
> xdlfile_t, though note that xdiff is fond if typedefs when
> Git usually is not).

>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> I didn't rename the functions, which have no conflict, but that would
> also be closer to xdiff's usual style. I don't know how far it is worth
> going; maybe this patch is even already too far.
>
> I noticed because I have a patch series which switches xdiff
> to git-compat-util, to try to use the st_* macros there.
>
>  xdiff/xdiffi.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
> index 67c1ccc..760fbb6 100644
> --- a/xdiff/xdiffi.c
> +++ b/xdiff/xdiffi.c
> @@ -708,7 +708,7 @@ static int score_cmp(struct split_score *s1, struct split_score *s2)
>   * Note that loops that are testing for changed lines in xdf->rchg do not need
>   * index bounding since the array is prepared with a zero at position -1 and N.
>   */
> -struct group {
> +struct xdlgroup {
>         /*
>          * The index of the first changed line in the group, or the index of
>          * the unchanged line above which the (empty) group is located.
> @@ -725,7 +725,7 @@ struct group {
>  /*
>   * Initialize g to point at the first group in xdf.
>   */
> -static void group_init(xdfile_t *xdf, struct group *g)
> +static void group_init(xdfile_t *xdf, struct xdlgroup *g)
>  {
>         g->start = g->end = 0;
>         while (xdf->rchg[g->end])
> @@ -736,7 +736,7 @@ static void group_init(xdfile_t *xdf, struct group *g)
>   * Move g to describe the next (possibly empty) group in xdf and return 0. If g
>   * is already at the end of the file, do nothing and return -1.
>   */
> -static inline int group_next(xdfile_t *xdf, struct group *g)
> +static inline int group_next(xdfile_t *xdf, struct xdlgroup *g)
>  {
>         if (g->end == xdf->nrec)
>                 return -1;
> @@ -752,7 +752,7 @@ static inline int group_next(xdfile_t *xdf, struct group *g)
>   * Move g to describe the previous (possibly empty) group in xdf and return 0.
>   * If g is already at the beginning of the file, do nothing and return -1.
>   */
> -static inline int group_previous(xdfile_t *xdf, struct group *g)
> +static inline int group_previous(xdfile_t *xdf, struct xdlgroup *g)
>  {
>         if (g->start == 0)
>                 return -1;
> @@ -769,7 +769,7 @@ static inline int group_previous(xdfile_t *xdf, struct group *g)
>   * following group, expand this group to include it. Return 0 on success or -1
>   * if g cannot be slid down.
>   */
> -static int group_slide_down(xdfile_t *xdf, struct group *g, long flags)
> +static int group_slide_down(xdfile_t *xdf, struct xdlgroup *g, long flags)
>  {
>         if (g->end < xdf->nrec &&
>             recs_match(xdf->recs[g->start], xdf->recs[g->end], flags)) {
> @@ -790,7 +790,7 @@ static int group_slide_down(xdfile_t *xdf, struct group *g, long flags)
>   * into a previous group, expand this group to include it. Return 0 on success
>   * or -1 if g cannot be slid up.
>   */
> -static int group_slide_up(xdfile_t *xdf, struct group *g, long flags)
> +static int group_slide_up(xdfile_t *xdf, struct xdlgroup *g, long flags)
>  {
>         if (g->start > 0 &&
>             recs_match(xdf->recs[g->start - 1], xdf->recs[g->end - 1], flags)) {
> @@ -818,7 +818,7 @@ static void xdl_bug(const char *msg)
>   * size.
>   */
>  int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
> -       struct group g, go;
> +       struct xdlgroup g, go;
>         long earliest_end, end_matching_other;
>         long groupsize;
>         unsigned int blank_lines;
> --
> 2.10.0.492.g14f803f