+static void
+_notmuch_message_ensure_message_file (notmuch_message_t *message)
+{
+ const char *filename;
+
+ if (message->message_file)
+ return;
+
+ filename = notmuch_message_get_filename (message);
+ if (unlikely (filename == NULL))
+ return;
+
+ message->message_file = _notmuch_message_file_open_ctx (message, filename);
+}
+
+const char *
+notmuch_message_get_header (notmuch_message_t *message, const char *header)
+{
+ _notmuch_message_ensure_message_file (message);
+ if (message->message_file == NULL)
+ return NULL;
+
+ return notmuch_message_file_get_header (message->message_file, header);
+}
+
+const char *
+notmuch_message_get_all_headers (notmuch_message_t *message)
+{
+ _notmuch_message_ensure_message_file (message);
+ if (message->message_file == NULL)
+ return NULL;
+
+ return notmuch_message_file_get_all_headers (message->message_file);
+}
+
+size_t
+notmuch_message_get_header_size (notmuch_message_t *message)
+{
+ _notmuch_message_ensure_message_file (message);
+ if (message->message_file == NULL)
+ return 0;
+
+ return notmuch_message_file_get_header_size (message->message_file);
+
+}
+