+size_t
+_notmuch_message_get_thread_depth (notmuch_message_t *message)
+{
+ return message->thread_depth;
+}
+
+void
+_notmuch_message_label_depths (notmuch_message_t *message,
+ size_t depth)
+{
+ message->thread_depth = depth;
+
+ for (notmuch_messages_t *messages = _notmuch_messages_create (message->replies);
+ notmuch_messages_valid (messages);
+ notmuch_messages_move_to_next (messages)) {
+ notmuch_message_t *child = notmuch_messages_get (messages);
+ _notmuch_message_label_depths (child, depth + 1);
+ }
+}
+
+const notmuch_string_list_t *
+_notmuch_message_get_references (notmuch_message_t *message)
+{
+ _notmuch_message_ensure_metadata (message, message->reference_list);
+ return message->reference_list;
+}
+
+static int
+_cmpmsg (const void *pa, const void *pb)
+{
+ notmuch_message_t **a = (notmuch_message_t **) pa;
+ notmuch_message_t **b = (notmuch_message_t **) pb;
+ time_t time_a = notmuch_message_get_date (*a);
+ time_t time_b = notmuch_message_get_date (*b);
+
+ if (time_a == time_b)
+ return 0;
+ else if (time_a < time_b)
+ return -1;
+ else
+ return 1;
+}
+
+notmuch_message_list_t *
+_notmuch_message_sort_subtrees (void *ctx, notmuch_message_list_t *list)
+{
+
+ size_t count = 0;
+ size_t capacity = 16;
+
+ if (! list)
+ return list;
+
+ void *local = talloc_new (NULL);
+ notmuch_message_list_t *new_list = _notmuch_message_list_create (ctx);
+ notmuch_message_t **message_array = talloc_zero_array (local, notmuch_message_t *, capacity);
+
+ for (notmuch_messages_t *messages = _notmuch_messages_create (list);
+ notmuch_messages_valid (messages);
+ notmuch_messages_move_to_next (messages)) {
+ notmuch_message_t *root = notmuch_messages_get (messages);
+ if (count >= capacity) {
+ capacity *= 2;
+ message_array = talloc_realloc (local, message_array, notmuch_message_t *, capacity);
+ }
+ message_array[count++] = root;
+ root->replies = _notmuch_message_sort_subtrees (root, root->replies);
+ }
+
+ qsort (message_array, count, sizeof (notmuch_message_t *), _cmpmsg);
+ for (size_t i = 0; i < count; i++) {
+ _notmuch_message_list_add_message (new_list, message_array[i]);
+ }
+
+ talloc_free (local);
+ talloc_free (list);
+ return new_list;
+}
+