Return the entries for this commit, the entries of the parent commits,
        and the difference between the two (current_files - parent_files)

def tree_structures_for(self, prefix, current_oid, parent_oids, prefixes):
        """
        Return the entries for this commit, the entries of the parent commits,
        and the difference between the two (current_files - parent_files)
        """
        if prefix and prefixes and prefix not in prefixes:
            return empty, empty

        parent_files = set()
        for oid in parent_oids:
            parent_files.update(self.entries_in_tree_oid(prefix, oid))

        current_files = self.entries_in_tree_oid(prefix, current_oid)
        return (current_files, parent_files), (current_files - parent_files)