+ /** Rename the file on disk referenced by this source to \param newname
+ *
+ * This method exists only for MIDI file sources, not for audio, which
+ * can never be renamed. It exists for MIDI so that we can get
+ * consistent and sane region/source numbering when regions are added
+ * manually (which never happens with audio).
+ */
+ int rename (const std::string& name);
+
+ bool safe_file_extension (const std::string& path) const {