Allow short pack names to git-pack-objects --unpacked=.

This allows us to pass just the file name of a pack rather than
the complete path when we want pack-objects to consider its
contents as though they were loose objects.  This can be helpful
if $GIT_OBJECT_DIRECTORY contains shell metacharacters which make
it cumbersome to pass complete paths safely in a shell script.
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

sha1_file.c

@@ -1203,6 +1203,24 @@ unsigned long find_pack_entry_one(const unsigned char *sha1,
 	return 0;
 }
 
+static int matches_pack_name(struct packed_git *p, const char *ig)
+{
+	const char *last_c, *c;
+
+	if (!strcmp(p->pack_name, ig))
+		return 0;
+
+	for (c = p->pack_name, last_c = c; *c;)
+		if (*c == '/')
+			last_c = ++c;
+		else
+			++c;
+	if (!strcmp(last_c, ig))
+		return 0;
+
+	return 1;
+}
+
 static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, const char **ignore_packed)
 {
 	struct packed_git *p;
@@ -1214,7 +1232,7 @@ static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e, cons
 		if (ignore_packed) {
 			const char **ig;
 			for (ig = ignore_packed; *ig; ig++)
-				if (!strcmp(p->pack_name, *ig))
+				if (!matches_pack_name(p, *ig))
 					break;
 			if (*ig)
 				continue;