From: Junio C Hamano <gitster@pobox.com>
To: Martin von Zweigbergk <martinvonz@gmail.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH 06/19] reset.c: remove unnecessary variable 'i'
Date: Wed, 09 Jan 2013 11:39:50 -0800 [thread overview]
Message-ID: <7vpq1e5ent.fsf@alter.siamese.dyndns.org> (raw)
In-Reply-To: <1357719376-16406-7-git-send-email-martinvonz@gmail.com> (Martin von Zweigbergk's message of "Wed, 9 Jan 2013 00:16:03 -0800")
Martin von Zweigbergk <martinvonz@gmail.com> writes:
> Throughout most of parse_args(), the variable 'i' remains at 0. In the
> remaining few cases, we can do pointer arithmentic on argv itself
> instead.
> ---
> This is clearly mostly a matter of taste. The remainder of the series
> does not depend on it in any way.
I agree that it indeed is a matter of taste between
(1) look at av[i], check with (i < ac) for the end, and increment i to
iterate over the arguments; and
(2) look at av[0], check with (0 < ac) for the end, and increment
av and decrement ac at the same time to iterate over the
arguments.
When (ac, av) appear as a pair, however, adjusting only av without
adjusting ac is asking for future trouble. It violates a common
expectation that av[ac] points at the NULL at the end of the list.
If a code chooses to use !av[0] as the terminating condition and
never looks at ac, then incrementing only av is fine, but in such a
case, the function probably should lose ac altogether.
> builtin/reset.c | 29 ++++++++++++++---------------
> 1 file changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/builtin/reset.c b/builtin/reset.c
> index 9473725..68be05c 100644
> --- a/builtin/reset.c
> +++ b/builtin/reset.c
> @@ -199,7 +199,6 @@ static void die_if_unmerged_cache(int reset_type)
> }
>
> const char **parse_args(int argc, const char **argv, const char *prefix, const char **rev_ret) {
> - int i = 0;
> const char *rev = "HEAD";
> unsigned char unused[20];
> /*
> @@ -210,34 +209,34 @@ const char **parse_args(int argc, const char **argv, const char *prefix, const c
> * git reset [-opts] -- <paths>...
> * git reset [-opts] <paths>...
> *
> - * At this point, argv[i] points immediately after [-opts].
> + * At this point, argv points immediately after [-opts].
> */
>
> - if (i < argc) {
> - if (!strcmp(argv[i], "--")) {
> - i++; /* reset to HEAD, possibly with paths */
> - } else if (i + 1 < argc && !strcmp(argv[i+1], "--")) {
> - rev = argv[i];
> - i += 2;
> + if (argc) {
> + if (!strcmp(argv[0], "--")) {
> + argv++; /* reset to HEAD, possibly with paths */
> + } else if (argc > 1 && !strcmp(argv[1], "--")) {
> + rev = argv[0];
> + argv += 2;
> }
> /*
> - * Otherwise, argv[i] could be either <rev> or <paths> and
> + * Otherwise, argv[0] could be either <rev> or <paths> and
> * has to be unambiguous.
> */
> - else if (!get_sha1_committish(argv[i], unused)) {
> + else if (!get_sha1_committish(argv[0], unused)) {
> /*
> - * Ok, argv[i] looks like a rev; it should not
> + * Ok, argv[0] looks like a rev; it should not
> * be a filename.
> */
> - verify_non_filename(prefix, argv[i]);
> - rev = argv[i++];
> + verify_non_filename(prefix, argv[0]);
> + rev = *argv++;
> } else {
> /* Otherwise we treat this as a filename */
> - verify_filename(prefix, argv[i], 1);
> + verify_filename(prefix, argv[0], 1);
> }
> }
> *rev_ret = rev;
> - return i < argc ? get_pathspec(prefix, argv + i) : NULL;
> + return *argv ? get_pathspec(prefix, argv) : NULL;
> }
>
> int cmd_reset(int argc, const char **argv, const char *prefix)
next prev parent reply other threads:[~2013-01-09 19:40 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-09 8:15 [PATCH 00/19] reset improvements Martin von Zweigbergk
2013-01-09 8:15 ` [PATCH 01/19] reset $pathspec: no need to discard index Martin von Zweigbergk
2013-01-09 8:15 ` [PATCH 02/19] reset $pathspec: exit with code 0 if successful Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 03/19] reset.c: pass pathspec around instead of (prefix, argv) pair Martin von Zweigbergk
2013-01-09 11:42 ` Matt Kraai
2013-01-09 19:26 ` Junio C Hamano
2013-01-10 11:05 ` Duy Nguyen
2013-01-10 23:09 ` Junio C Hamano
2013-01-11 11:10 ` Duy Nguyen
2013-01-09 8:16 ` [PATCH 04/19] reset: don't allow "git reset -- $pathspec" in bare repo Martin von Zweigbergk
2013-01-09 19:32 ` Junio C Hamano
2013-01-10 8:24 ` Martin von Zweigbergk
2013-01-10 18:04 ` Junio C Hamano
2013-01-09 8:16 ` [PATCH 05/19] reset.c: extract function for parsing arguments Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 06/19] reset.c: remove unnecessary variable 'i' Martin von Zweigbergk
2013-01-09 19:39 ` Junio C Hamano [this message]
2013-01-10 8:41 ` Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 07/19] reset.c: extract function for updating {ORIG,}HEAD Martin von Zweigbergk
2013-01-09 11:54 ` Matt Kraai
2013-01-09 8:16 ` [PATCH 08/19] reset.c: share call to die_if_unmerged_cache() Martin von Zweigbergk
2013-01-09 19:48 ` Junio C Hamano
2013-01-10 8:51 ` Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 09/19] reset.c: replace switch by if-else Martin von Zweigbergk
2013-01-09 19:53 ` Junio C Hamano
2013-01-11 6:35 ` Martin von Zweigbergk
2013-01-11 17:12 ` Junio C Hamano
2013-01-09 8:16 ` [PATCH 10/19] reset --keep: only write index file once Martin von Zweigbergk
2013-01-09 19:55 ` Junio C Hamano
2013-01-09 8:16 ` [PATCH 11/19] reset: avoid redundant error message Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 12/19] reset.c: move update_index_refresh() call out of read_from_tree() Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 13/19] reset.c: move lock, write and commit out of update_index_refresh() Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 14/19] reset [--mixed]: don't write index file twice Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 15/19] reset.c: finish entire cmd_reset() whether or not pathspec is given Martin von Zweigbergk
2013-01-09 19:59 ` Junio C Hamano
2013-01-09 8:16 ` [PATCH 16/19] reset [--mixed] --quiet: don't refresh index Martin von Zweigbergk
2013-01-09 17:01 ` Jeff King
2013-01-09 18:43 ` Martin von Zweigbergk
2013-01-09 19:12 ` Junio C Hamano
2013-01-09 19:38 ` Martin von Zweigbergk
2013-01-09 20:05 ` Junio C Hamano
2013-01-09 8:16 ` [PATCH 17/19] reset $sha1 $pathspec: require $sha1 only to be treeish Martin von Zweigbergk
2013-01-09 20:23 ` Junio C Hamano
2013-01-09 8:16 ` [PATCH 18/19] reset: allow reset on unborn branch Martin von Zweigbergk
2013-01-09 8:16 ` [PATCH 19/19] reset [--mixed]: use diff-based reset whether or not pathspec was given Martin von Zweigbergk
2013-01-09 20:27 ` Junio C Hamano
2013-01-15 5:47 ` [PATCH v2 00/19] reset improvements Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 01/19] reset $pathspec: no need to discard index Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 02/19] reset $pathspec: exit with code 0 if successful Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 03/19] reset.c: pass pathspec around instead of (prefix, argv) pair Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 04/19] reset: don't allow "git reset -- $pathspec" in bare repo Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 05/19] reset.c: extract function for parsing arguments Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 06/19] reset.c: remove unnecessary variable 'i' Martin von Zweigbergk
[not found] ` <A5E8E180685CEF45AB9E737A010799805E00DD@cdnz-ex1.corp.cubic.cub>
2013-01-15 18:36 ` Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 07/19] reset.c: extract function for updating {ORIG_,}HEAD Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 08/19] reset.c: share call to die_if_unmerged_cache() Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 09/19] reset --keep: only write index file once Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 10/19] reset: avoid redundant error message Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 11/19] reset.c: replace switch by if-else Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 12/19] reset.c: move update_index_refresh() call out of read_from_tree() Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 13/19] reset.c: move lock, write and commit out of update_index_refresh() Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 14/19] reset [--mixed]: only write index file once Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 15/19] reset.c: finish entire cmd_reset() whether or not pathspec is given Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 16/19] reset.c: inline update_index_refresh() Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 17/19] reset $sha1 $pathspec: require $sha1 only to be treeish Martin von Zweigbergk
2013-01-16 18:00 ` [PATCH v2 17/19] fixup! " Martin von Zweigbergk
2013-01-16 18:08 ` Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 18/19] reset: allow reset on unborn branch Martin von Zweigbergk
2013-01-15 5:47 ` [PATCH v2 19/19] reset [--mixed]: use diff-based reset whether or not pathspec was given Martin von Zweigbergk
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