Function is_safe_temp_dir 

pub fn is_safe_temp_dir(
    path: &Path,
    user: Option<u32>,
    accessible: impl Fn(&Path) -> bool,
) -> bool

Whether a directory is safe to keep temporary files in: accessible and, where user is given, a real directory (not a link) that user owns and no one else can write to. music21’s _isSafeTempDir.