7846: limit fnmatch pattern cache to _MAXCACHE=100 entries.

Patch by Andrew Clegg.
This commit is contained in:
R. David Murray 2010-07-09 12:23:21 +00:00
parent facb0e9a76
commit ea340a317a
4 changed files with 22 additions and 1 deletions

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@ -16,6 +16,7 @@ __all__ = ["filter", "fnmatch","fnmatchcase","translate"]
_cache = {} # Maps text patterns to compiled regexen.
_cacheb = {} # Ditto for bytes patterns.
_MAXCACHE = 100 # Maximum size of caches
def fnmatch(name, pat):
"""Test whether FILENAME matches PATTERN.
@ -48,6 +49,8 @@ def _compile_pattern(pat):
res = bytes(res_str, 'ISO-8859-1')
else:
res = translate(pat)
if len(cache) >= _MAXCACHE:
cache.clear()
cache[pat] = regex = re.compile(res)
return regex.match

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@ -3,7 +3,7 @@
from test import support
import unittest
from fnmatch import fnmatch, fnmatchcase
from fnmatch import fnmatch, fnmatchcase, _MAXCACHE, _cache, _cacheb
class FnmatchTestCase(unittest.TestCase):
@ -60,6 +60,21 @@ class FnmatchTestCase(unittest.TestCase):
self.check_match(b'test\xff', b'te*\xff')
self.check_match(b'foo\nbar', b'foo*')
def test_cache_clearing(self):
# check that caches do not grow too large
# http://bugs.python.org/issue7846
# string pattern cache
for i in range(_MAXCACHE + 1):
fnmatch('foo', '?' * i)
self.assertLessEqual(len(_cache), _MAXCACHE)
# bytes pattern cache
for i in range(_MAXCACHE + 1):
fnmatch(b'foo', b'?' * i)
self.assertLessEqual(len(_cacheb), _MAXCACHE)
def test_main():
support.run_unittest(FnmatchTestCase)

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@ -146,6 +146,7 @@ Vadim Chugunov
David Cinege
Mike Clarkson
Brad Clements
Andrew Clegg
Steve Clift
Nick Coghlan
Josh Cogliati

View File

@ -470,6 +470,8 @@ C-API
Library
-------
- Issue #7646: The fnmatch pattern cache no longer grows without bound.
- Issue #9136: Fix 'dictionary changed size during iteration'
RuntimeError produced when profiling the decimal module. This was
due to a dangerous iteration over 'locals()' in Context.__init__.