"""Read and cache directory listings. The listdir() routine returns a sorted list of the files in a directory,using a cache to avoid reading the directory more often than necessary.The annotate() routine appends slashes to directories.""" import os __all__ = ["listdir", "opendir", "annotate", "reset"] cache = {} def reset():    """Reset the cache completely."""    global cache    cache = {} def listdir(path):    """List directory contents, using cache."""    try:        cached_mtime, list = cache[path]        del cache[path]    except KeyError:        cached_mtime, list = -1, []    mtime = os.stat(path).st_mtime    if mtime != cached_mtime:        list = os.listdir(path)        list.sort()    cache[path] = mtime, list    return list opendir = listdir # XXX backward compatibility def annotate(head, list):    """Add '/' suffixes to directories."""    for i in range(len(list)):        if os.path.isdir(os.path.join(head, list[i])):            list[i] = list[i] + '/'