[PATCH] revision: introduce ref@{N..M} syntax.

[Junio C Hamano <junkio@cox.net>]

Brian Gernhardt <benji@silverinsanity.com> writes:

>> ** jc/reflog (Thu Dec 14 15:58:56 2006 -0800) 1 commit
>>  - Teach show-branch how to show ref-log data.
>>
>> A strawman to make reflog data a bit more browsable; it would be
>> useful while recovering from a mistake you made recently.  Not
>> essential and can wait or be dropped if people do not find it
>> useful.
>
> I'd prefer not to add clutter into show-branch.  I use it on a regular
> basis to see what I've added to what topic branch recently,  and to
> look at branches before rebasing.  It also just seems like the  wrong
> place to have that kind of data, although I guess it's more  useful
> for people who do merges more often than I do.

I happen to find it a reasonable way to present how a topic was
rewind and rebuilt, but I think that is I rewind my internal
topic (i.e. the parts that have not been merged into 'next' yet)
all the time.

> What about a "git reflog [<branch>]" command instead?  Would show
> output similar to "git log" (or "git show-branch" for brevity).

This is not a 'git reflog' command, but is another way to show
the tips of reflog entries (use it with 'git show').  I find the
show-branch variant easier to see, but you can judge for
yourself.

This happens to show why pruning while not culling reflog
entries is a bad idea.  If your master@{2} is gone due to rewind
and prune, and master@{0}, master@{1} and master@{3} are still
available, the pattern master@{0..3} would not give you a usable
result.

-- >8 --
This allows you to add between Nth and Mth (inclusive) reflog entries.
"git show master@{1} master@{2} master@{3}" is equivalent to
"git show master@{1..3}".

Signed-off-by: Junio C Hamano <junkio@cox.net>
---
 revision.c |   59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 59 insertions(+), 0 deletions(-)

diff --git a/revision.c b/revision.c
index 993bb66..3f1d65e 100644
--- a/revision.c
+++ b/revision.c
@@ -592,6 +592,59 @@ static void prepare_show_merge(struct rev_info *revs)
 	revs->prune_data = prune;
 }
 
+static int parse_digits(const char *p, int len)
+{
+	int accum = 0;
+	while (0 < len--) {
+		int ch = *p++;
+		if ('0' <= ch && ch <= '9')
+			accum = accum * 10 + ch - '0';
+		else
+			return -1;
+	}
+	return accum;
+}
+
+static int list_of_reflog_entries(const char *arg, const char *dotdot,
+				  struct rev_info *revs, int flags)
+{
+	/*
+	 * "ref@{N..M}" -- push them for "git show".
+	 * dotdot points at the first dot
+	 */
+	int n, m, i, added;
+	int len;
+	char *at_brace = strstr(arg, "@{");
+
+
+	if (!at_brace)
+		return 0;
+	len = strlen(arg);
+	if (arg[len-1] != '}')
+		return 0;
+	if ((m = parse_digits(dotdot + 2, len - (dotdot - arg) - 3)) < 0)
+		return 0;
+	if ((n = parse_digits(at_brace + 2, dotdot - at_brace - 2)) < 0)
+		return 0;
+	if (n > m)
+		return 0;
+
+	added = 0;
+	for (i = n; i <= m; i++) {
+		char buf[1024];
+		unsigned char sha1[20];
+
+		snprintf(buf, sizeof(buf), "%.*s@{%d}",
+			 (int) (at_brace - arg), arg, i);
+		if (!get_sha1(buf, sha1)) {
+			/* this is synthetic -- do not check filename */
+			handle_revision_arg(buf, revs, flags, 1);
+			added = 1;
+		}
+	}
+	return added;
+}
+
 int handle_revision_arg(const char *arg, struct rev_info *revs,
 			int flags,
 			int cant_be_filename)
@@ -648,7 +701,13 @@ int handle_revision_arg(const char *arg, struct rev_info *revs,
 			add_pending_object(revs, &b->object, next);
 			return 0;
 		}
+
 		*dotdot = '.';
+
+		/* It could be ref@{N..M} */
+		if (list_of_reflog_entries(arg, dotdot, revs, flags))
+			return 0;
+
 	}
 	dotdot = strstr(arg, "^@");
 	if (dotdot && !dotdot[2]) {
-- 
1.4.4.2.g83c5