/** Return the path prefixed by the target root, unless it already is prefixed. */
Pathname assertRootPrefix( const Pathname & path_r ) const
{ return Pathname::assertprefix( root(), path_r ); }
/** Return the path prefixed by the target root, unless it already is prefixed. */
Pathname assertRootPrefix( const Pathname & path_r ) const
{ return Pathname::assertprefix( root(), path_r ); }