lib-storage: Implement mailbox_list_notify_flush()

This flushes any pending notifications. For now it only checks if there's
a pending notification waiting for a timeout. It could also stat() the
files to make sure, but that's probably unnecessary.

src/lib-storage/list/mailbox-list-index-notify.c

@@ -876,3 +876,12 @@ void mailbox_list_index_notify_wait(struct mailbox_list_notify *notify,
 		notify_update_stat(inotify);
 	}
 }
+
+void mailbox_list_index_notify_flush(struct mailbox_list_notify *notify)
+{
+	struct mailbox_list_notify_index *inotify =
+		(struct mailbox_list_notify_index *)notify;
+
+	if (inotify->to_notify != NULL)
+		notify_now_callback(inotify);
+}

src/lib-storage/list/mailbox-list-index.c

@@ -772,6 +772,7 @@ static void mailbox_list_index_created(struct mailbox_list *list)
 	v->notify_next = mailbox_list_index_notify_next;
 	v->notify_deinit = mailbox_list_index_notify_deinit;
 	v->notify_wait = mailbox_list_index_notify_wait;
+	v->notify_flush = mailbox_list_index_notify_flush;
 
 	MODULE_CONTEXT_SET(list, mailbox_list_index_module, ilist);
 

src/lib-storage/list/mailbox-list-index.h

@@ -198,6 +198,7 @@ int mailbox_list_index_notify_next(struct mailbox_list_notify *notify,
 void mailbox_list_index_notify_wait(struct mailbox_list_notify *notify,
 				    void (*callback)(void *context),
 				    void *context);
+void mailbox_list_index_notify_flush(struct mailbox_list_notify *notify);
 
 void mailbox_list_index_status_init_mailbox(struct mailbox_vfuncs *v);
 void mailbox_list_index_backend_init_mailbox(struct mailbox *box,

src/lib-storage/mailbox-list-notify.c

@@ -33,3 +33,9 @@ void mailbox_list_notify_wait(struct mailbox_list_notify *notify,
 {
 	notify->list->v.notify_wait(notify, callback, context);
 }
+
+void mailbox_list_notify_flush(struct mailbox_list_notify *notify)
+{
+	if (notify->list->v.notify_flush != NULL)
+		notify->list->v.notify_flush(notify);
+}

src/lib-storage/mailbox-list-notify.h

@@ -56,5 +56,7 @@ int mailbox_list_notify_next(struct mailbox_list_notify *notify,
 /* Call the specified callback when something changes. */
 void mailbox_list_notify_wait(struct mailbox_list_notify *notify,
 			      void (*callback)(void *context), void *context);
+/* Flush any delayed notifications now. */
+void mailbox_list_notify_flush(struct mailbox_list_notify *notify);
 
 #endif

src/lib-storage/mailbox-list-private.h

@@ -89,6 +89,7 @@ struct mailbox_list_vfuncs {
 	void (*notify_deinit)(struct mailbox_list_notify *notify);
 	void (*notify_wait)(struct mailbox_list_notify *notify,
 			    void (*callback)(void *context), void *context);
+	void (*notify_flush)(struct mailbox_list_notify *notify);
 };
 
 struct mailbox_list_module_register {