pack-objects --unpacked=<existing pack> option.

Incremental repack without -a essentially boils down to:

	rev-list --objects --unpacked --all |
        pack-objects $new_pack

which picks up all loose objects that are still live and creates
a new pack.

This implements --unpacked=<existing pack> option to tell the
revision walking machinery to pretend as if objects in such a
pack are unpacked for the purpose of object listing.  With this,
we could say:

	rev-list --objects --unpacked=$active_pack --all |
	pack-objects $new_pack

instead, to mean "all live loose objects but pretend as if
objects that are in this pack are also unpacked".  The newly
created pack would be perfect for updating $active_pack by
replacing it.

Since pack-objects now knows how to do the rev-list's work
itself internally, you can also write the above example by:

	pack-objects --unpacked=$active_pack --all $new_pack </dev/null

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 22 insertions, 2 deletions

diff --git a/revision.c b/revision.c
index db01682..6a2539b 100644
--- a/revision.c
+++ b/revision.c
@@ -416,7 +416,8 @@ static void limit_list(struct rev_info *revs)
 
 		if (revs->max_age != -1 && (commit->date < revs->max_age))
 			obj->flags |= UNINTERESTING;
-		if (revs->unpacked && has_sha1_pack(obj->sha1))
+		if (revs->unpacked &&
+		    has_sha1_pack(obj->sha1, revs->ignore_packed))
 			obj->flags |= UNINTERESTING;
 		add_parents_to_list(revs, commit, &list);
 		if (obj->flags & UNINTERESTING) {
@@ -671,6 +672,16 @@ int handle_revision_arg(const char *arg, struct rev_info *revs,
 	return 0;
 }
 
+static void add_ignore_packed(struct rev_info *revs, const char *name)
+{
+	int num = ++revs->num_ignore_packed;
+
+	revs->ignore_packed = xrealloc(revs->ignore_packed,
+				       sizeof(const char **) * (num + 1));
+	revs->ignore_packed[num-1] = name;
+	revs->ignore_packed[num] = NULL;
+}
+
 /*
  * Parse revision information, filling in the "rev_info" structure,
  * and removing the used arguments from the argument list.
@@ -811,6 +822,14 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 			}
 			if (!strcmp(arg, "--unpacked")) {
 				revs->unpacked = 1;
+				free(revs->ignore_packed);
+				revs->ignore_packed = NULL;
+				revs->num_ignore_packed = 0;
+				continue;
+			}
+			if (!strncmp(arg, "--unpacked=", 11)) {
+				revs->unpacked = 1;
+				add_ignore_packed(revs, arg+11);
 				continue;
 			}
 			if (!strcmp(arg, "-r")) {
@@ -1057,7 +1076,8 @@ struct commit *get_revision(struct rev_info *revs)
 		 */
 		if (!revs->limited) {
 			if ((revs->unpacked &&
-			     has_sha1_pack(commit->object.sha1)) ||
+			     has_sha1_pack(commit->object.sha1,
+					   revs->ignore_packed)) ||
 			    (revs->max_age != -1 &&
 			     (commit->date < revs->max_age)))
 				continue;