upload-pack: add get_reachable_list()

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

object.h

@@ -31,7 +31,7 @@ struct object_array {
  * revision.h:      0---------10                                26
  * fetch-pack.c:    0---4
  * walker.c:        0-2
- * upload-pack.c:               11----------------19
+ * upload-pack.c:       4       11----------------19
  * builtin/blame.c:               12-13
  * bisect.c:                               16
  * bundle.c:                               16

upload-pack.c

@@ -456,7 +456,8 @@ static int is_our_ref(struct object *o)
  * on successful case, it's up to the caller to close cmd->out
  */
 static int do_reachable_revlist(struct child_process *cmd,
-				struct object_array *src)
+				struct object_array *src,
+				struct object_array *reachable)
 {
 	static const char *argv[] = {
 		"rev-list", "--stdin", NULL,
@@ -487,6 +488,8 @@ static int do_reachable_revlist(struct child_process *cmd,
 		o = get_indexed_object(--i);
 		if (!o)
 			continue;
+		if (reachable && o->type == OBJ_COMMIT)
+			o->flags &= ~TMP_MARK;
 		if (!is_our_ref(o))
 			continue;
 		memcpy(namebuf + 1, oid_to_hex(&o->oid), GIT_SHA1_HEXSZ);
@@ -496,8 +499,13 @@ static int do_reachable_revlist(struct child_process *cmd,
 	namebuf[40] = '\n';
 	for (i = 0; i < src->nr; i++) {
 		o = src->objects[i].item;
-		if (is_our_ref(o))
+		if (is_our_ref(o)) {
+			if (reachable)
+				add_object_array(o, NULL, reachable);
 			continue;
+		}
+		if (reachable && o->type == OBJ_COMMIT)
+			o->flags |= TMP_MARK;
 		memcpy(namebuf, oid_to_hex(&o->oid), GIT_SHA1_HEXSZ);
 		if (write_in_full(cmd->in, namebuf, 41) < 0)
 			goto error;
@@ -518,13 +526,51 @@ error:
 	return -1;
 }
 
+static int get_reachable_list(struct object_array *src,
+			      struct object_array *reachable)
+{
+	struct child_process cmd = CHILD_PROCESS_INIT;
+	int i;
+	struct object *o;
+	char namebuf[42]; /* ^ + SHA-1 + LF */
+
+	if (do_reachable_revlist(&cmd, src, reachable) < 0)
+		return -1;
+
+	while ((i = read_in_full(cmd.out, namebuf, 41)) == 41) {
+		struct object_id sha1;
+
+		if (namebuf[40] != '\n' || get_oid_hex(namebuf, &sha1))
+			break;
+
+		o = lookup_object(sha1.hash);
+		if (o && o->type == OBJ_COMMIT) {
+			o->flags &= ~TMP_MARK;
+		}
+	}
+	for (i = get_max_object_index(); 0 < i; i--) {
+		o = get_indexed_object(i - 1);
+		if (o && o->type == OBJ_COMMIT &&
+		    (o->flags & TMP_MARK)) {
+			add_object_array(o, NULL, reachable);
+				o->flags &= ~TMP_MARK;
+		}
+	}
+	close(cmd.out);
+
+	if (finish_command(&cmd))
+		return -1;
+
+	return 0;
+}
+
 static int has_unreachable(struct object_array *src)
 {
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	char buf[1];
 	int i;
 
-	if (do_reachable_revlist(&cmd, src) < 0)
+	if (do_reachable_revlist(&cmd, src, NULL) < 0)
 		return 1;
 
 	/*