+ /* Before we do any real work, (especially before doing a
+ * potential SHA-1 computation on the entire file's contents),
+ * let's make sure that what we're looking at looks like an
+ * actual email message.
+ */
+ from = notmuch_message_file_get_header (message_file, "from");
+ subject = notmuch_message_file_get_header (message_file, "subject");
+ to = notmuch_message_file_get_header (message_file, "to");
+
+ if (from == NULL &&
+ subject == NULL &&
+ to == NULL)
+ {
+ ret = NOTMUCH_STATUS_FILE_NOT_EMAIL;
+ goto DONE;
+ }
+
+ /* Now that we're sure it's mail, the first order of business
+ * is to find a message ID (or else create one ourselves). */