git-bundle: Make thin packs

Thin packs are way smaller, but they rely on the receiving end to have the
base objects. However, Git's pack protocol also uses thin packs by
default. So make the packs contained in bundles thin, since bundles are
just another transport.

The patch looks a bit bigger than intended, mainly because --thin
_implies_ that pack-objects should run its own rev-list. Therefore, this
patch removes all the stuff we used to roll rev-list ourselves.

This commit also changes behaviour slightly: since we now know early
enough if a specified ref is _not_ contained in the pack, we can avoid
putting that ref into the pack. So, we don't die() here, but warn()
instead, and skip that ref.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <junkio@cox.net>

builtin-bundle.c

@@ -257,45 +257,15 @@ static int list_heads(struct bundle_header *header, int argc, const char **argv)
 	return list_refs(&header->references, argc, argv);
 }
 
-static void show_commit(struct commit *commit)
-{
-	write_or_die(1, sha1_to_hex(commit->object.sha1), 40);
-	write_or_die(1, "\n", 1);
-	if (commit->parents) {
-		free_commit_list(commit->parents);
-		commit->parents = NULL;
-	}
-}
-
-static void show_object(struct object_array_entry *p)
-{
-	/* An object with name "foo\n0000000..." can be used to
-	 * confuse downstream git-pack-objects very badly.
-	 */
-	const char *ep = strchr(p->name, '\n');
-	int len = ep ? ep - p->name : strlen(p->name);
-	write_or_die(1, sha1_to_hex(p->item->sha1), 40);
-	write_or_die(1, " ", 1);
-	if (len)
-		write_or_die(1, p->name, len);
-	write_or_die(1, "\n", 1);
-}
-
-static void show_edge(struct commit *commit)
-{
-	; /* nothing to do */
-}
-
 static int create_bundle(struct bundle_header *header, const char *path,
 		int argc, const char **argv)
 {
 	int bundle_fd = -1;
 	const char **argv_boundary = xmalloc((argc + 4) * sizeof(const char *));
-	const char **argv_pack = xmalloc(4 * sizeof(const char *));
+	const char **argv_pack = xmalloc(5 * sizeof(const char *));
 	int pid, in, out, i, status;
 	char buffer[1024];
 	struct rev_info revs;
-	struct object_array tips;
 
 	bundle_fd = (!strcmp(path, "-") ? 1 :
 			open(path, O_CREAT | O_WRONLY, 0666));
@@ -319,31 +289,31 @@ static int create_bundle(struct bundle_header *header, const char *path,
 	pid = fork_with_pipe(argv_boundary, NULL, &out);
 	if (pid < 0)
 		return -1;
-	while ((i = read_string(out, buffer, sizeof(buffer))) > 0)
+	while ((i = read_string(out, buffer, sizeof(buffer))) > 0) {
+		unsigned char sha1[20];
 		if (buffer[0] == '-') {
-			unsigned char sha1[20];
 			write_or_die(bundle_fd, buffer, i);
 			if (!get_sha1_hex(buffer + 1, sha1)) {
 				struct object *object = parse_object(sha1);
 				object->flags |= UNINTERESTING;
 				add_pending_object(&revs, object, buffer);
 			}
+		} else if (!get_sha1_hex(buffer, sha1)) {
+			struct object *object = parse_object(sha1);
+			object->flags |= SHOWN;
 		}
+	}
 	while ((i = waitpid(pid, &status, 0)) < 0)
 		if (errno != EINTR)
 			return error("rev-list died");
 	if (!WIFEXITED(status) || WEXITSTATUS(status))
 		return error("rev-list died %d", WEXITSTATUS(status));
 
 	/* write references */
-	revs.tag_objects = 1;
-	revs.tree_objects = 1;
-	revs.blob_objects = 1;
 	argc = setup_revisions(argc, argv, &revs, NULL);
 	if (argc > 1)
 		return error("unrecognized argument: %s'", argv[1]);
 
-	memset(&tips, 0, sizeof(tips));
 	for (i = 0; i < revs.pending.nr; i++) {
 		struct object_array_entry *e = revs.pending.objects + i;
 		unsigned char sha1[20];
@@ -353,11 +323,20 @@ static int create_bundle(struct bundle_header *header, const char *path,
 			continue;
 		if (dwim_ref(e->name, strlen(e->name), sha1, &ref) != 1)
 			continue;
+		/*
+		 * Make sure the refs we wrote out is correct; --max-count and
+		 * other limiting options could have prevented all the tips
+		 * from getting output.
+		 */
+		if (!(e->item->flags & SHOWN)) {
+			warn("ref '%s' is excluded by the rev-list options",
+				e->name);
+			continue;
+		}
 		write_or_die(bundle_fd, sha1_to_hex(e->item->sha1), 40);
 		write_or_die(bundle_fd, " ", 1);
 		write_or_die(bundle_fd, ref, strlen(ref));
 		write_or_die(bundle_fd, "\n", 1);
-		add_object_array(e->item, e->name, &tips);
 		free(ref);
 	}
 
@@ -368,39 +347,27 @@ static int create_bundle(struct bundle_header *header, const char *path,
 	argv_pack[0] = "pack-objects";
 	argv_pack[1] = "--all-progress";
 	argv_pack[2] = "--stdout";
-	argv_pack[3] = NULL;
+	argv_pack[3] = "--thin";
+	argv_pack[4] = NULL;
 	in = -1;
 	out = bundle_fd;
 	pid = fork_with_pipe(argv_pack, &in, &out);
 	if (pid < 0)
 		return error("Could not spawn pack-objects");
-	close(1);
-	dup2(in, 1);
+	for (i = 0; i < revs.pending.nr; i++) {
+		struct object *object = revs.pending.objects[i].item;
+		if (object->flags & UNINTERESTING)
+			write(in, "^", 1);
+		write(in, sha1_to_hex(object->sha1), 40);
+		write(in, "\n", 1);
+	}
 	close(in);
-	prepare_revision_walk(&revs);
-	mark_edges_uninteresting(revs.commits, &revs, show_edge);
-	traverse_commit_list(&revs, show_commit, show_object);
-	close(1);
 	while (waitpid(pid, &status, 0) < 0)
 		if (errno != EINTR)
 			return -1;
 	if (!WIFEXITED(status) || WEXITSTATUS(status))
 		return error ("pack-objects died");
 
-	/*
-	 * Make sure the refs we wrote out is correct; --max-count and
-	 * other limiting options could have prevented all the tips
-	 * from getting output.
-	 */
-	status = 0;
-	for (i = 0; i < tips.nr; i++) {
-		if (!(tips.objects[i].item->flags & SHOWN)) {
-			status = 1;
-			error("%s: not included in the resulting pack",
-			      tips.objects[i].name);
-		}
-	}
-
 	return status;
 }