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 __all__ = ["listdir", "opendir", "annotate", "reset"]
  10
  11 cache = {}
  12
  13 def reset():
  14     """Reset the cache completely."""
  15     global cache
  16     cache = {}
  17
  18 def listdir(path):
  19     """List directory contents, using cache."""
  20     try:
  21         cached_mtime, list = cache[path]
  22         del cache[path]
  23     except KeyError:
  24         cached_mtime, list = -1, []
  25     mtime = os.stat(path).st_mtime
  26     if mtime != cached_mtime:
  27         list = os.listdir(path)
  28         list.sort()
  29     cache[path] = mtime, list
  30     return list
  31
  32 opendir = listdir # XXX backward compatibility
  33
  34 def annotate(head, list):
  35     """Add '/' suffixes to directories."""
  36     for i in range(len(list)):
  37         if os.path.isdir(os.path.join(head, list[i])):
  38             list[i] = list[i] + '/'