lib-storage: Return vsize=0 from mailbox list index for empty mailboxes.

If it's known that the mailbox has no mails, there's no reason to open the
mailbox to see that its size is 0.

diff --git a/src/lib-storage/list/mailbox-list-index-status.c b/src/lib-storage/list/mailbox-list-index-status.c
index a97369d18faabacf80058918174b6f0dae52a31c..ad1bf48549cb796c25a574eb825b66482848bfb1 100644 (file)
--- a/src/lib-storage/list/mailbox-list-index-status.c
+++ b/src/lib-storage/list/mailbox-list-index-status.c
@@ -264,8 +264,13 @@ static int index_list_get_cached_vsize(struct mailbox *box, uoff_t *vsize_r)
        ret = mailbox_list_index_status(box->list, view, seq,
                                        STATUS_MESSAGES | STATUS_UIDNEXT,
                                        &status, NULL, &vsize) ? 1 : 0;
-       if (ret > 0 && (vsize.highest_uid + 1 != status.uidnext ||
-                       vsize.message_count != status.messages)) {
+       if (status.messages == 0 && status.uidnext > 0) {
+               /* mailbox is empty. its size has to be zero, regardless of
+                  what the vsize header says. */
+               vsize.vsize = 0;
+               ret = 1;
+       } else if (ret > 0 && (vsize.highest_uid + 1 != status.uidnext ||
+                              vsize.message_count != status.messages)) {
                /* out of date vsize info */
                ret = 0;
        }