Lib/dircache.py

   1 """Read and cache directory listings.
   2
   3 The listdir() routine returns a sorted list of the files in a directory,
   4 using a cache to avoid reading the directory more often than necessary.
   5 The annotate() routine appends slashes to directories."""
   6
   7 import os
   8
   9 cache = {}
  10
  11 def listdir(path):
  12     """List directory contents, using cache."""
  13     try:
  14         cached_mtime, list = cache[path]
  15         del cache[path]
  16     except KeyError:
  17         cached_mtime, list = -1, []
  18     try:
  19         mtime = os.stat(path)[8]
  20     except os.error:
  21         return []
  22     if mtime <> cached_mtime:
  23         try:
  24             list = os.listdir(path)
  25         except os.error:
  26             return []
  27         list.sort()
  28     cache[path] = mtime, list
  29     return list
  30
  31 opendir = listdir # XXX backward compatibility
  32
  33 def annotate(head, list):
  34     """Add '/' suffixes to directories."""
  35     for i in range(len(list)):
  36         if os.path.isdir(os.path.join(head, list[i])):
  37             list[i] = list[i] + '/'