Staging
v0.5.1
v0.5.1
"""Maintain a cache of stat() information on files.
There are functions to reset the cache or to selectively remove items.
"""
import os
from stat import *
# The cache.
# Keys are pathnames, values are `os.stat' outcomes.
#
cache = {}
def stat(path):
"""Stat a file, possibly out of the cache."""
ret = cache.get(path, None)
if ret is not None:
return ret
cache[path] = ret = os.stat(path)
return ret
def reset():
"""Reset the cache completely."""
cache.clear()
def forget(path):
"""Remove a given item from the cache, if it exists."""
try:
del cache[path]
except KeyError:
pass
def forget_prefix(prefix):
"""Remove all pathnames with a given prefix."""
n = len(prefix)
for path in cache.keys():
if path[:n] == prefix:
forget(path)
def forget_dir(prefix):
"""Forget about a directory and all entries in it, but not about
entries in subdirectories."""
import os.path
prefix = os.path.dirname(os.path.join(prefix, "xxx"))
forget(prefix)
for path in cache.keys():
if path.startswith(prefix) and os.path.dirname(path) == prefix:
forget(path)
def forget_except_prefix(prefix):
"""Remove all pathnames except with a given prefix.
Normally used with prefix = '/' after a chdir()."""
n = len(prefix)
for path in cache.keys():
if path[:n] <> prefix:
forget(path)
def isdir(path):
"""Check for directory."""
try:
st = stat(path)
except os.error:
return 0
return S_ISDIR(st[ST_MODE])