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cpython/Lib/fnmatch.py
R. David Murray 0425a8ea72 Fix 'refleak' introduced by fnmatch cache purge tests.
This introduces a 'purge' function for the fnmatch module analogous
to the 'purge' function in the re module.
2010-07-10 13:52:13 +00:00

125 lines
3.5 KiB
Python

"""Filename matching with shell patterns.
fnmatch(FILENAME, PATTERN) matches according to the local convention.
fnmatchcase(FILENAME, PATTERN) always takes case in account.
The functions operate by translating the pattern into a regular
expression. They cache the compiled regular expressions for speed.
The function translate(PATTERN) returns a regular expression
corresponding to PATTERN. (It does not compile it.)
"""
import re
__all__ = ["filter", "fnmatch", "fnmatchcase", "purge", "translate"]
_cache = {} # Maps text patterns to compiled regexen.
_cacheb = {} # Ditto for bytes patterns.
_MAXCACHE = 100 # Maximum size of caches
def purge():
"""Clear the pattern cache"""
_cache.clear()
_cacheb.clear()
def fnmatch(name, pat):
"""Test whether FILENAME matches PATTERN.
Patterns are Unix shell style:
* matches everything
? matches any single character
[seq] matches any character in seq
[!seq] matches any char not in seq
An initial period in FILENAME is not special.
Both FILENAME and PATTERN are first case-normalized
if the operating system requires it.
If you don't want this, use fnmatchcase(FILENAME, PATTERN).
"""
import os
name = os.path.normcase(name)
pat = os.path.normcase(pat)
return fnmatchcase(name, pat)
def _compile_pattern(pat):
cache = _cacheb if isinstance(pat, bytes) else _cache
regex = cache.get(pat)
if regex is None:
if isinstance(pat, bytes):
pat_str = str(pat, 'ISO-8859-1')
res_str = translate(pat_str)
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
def filter(names, pat):
"""Return the subset of the list NAMES that match PAT"""
import os,posixpath
result = []
pat = os.path.normcase(pat)
match = _compile_pattern(pat)
if os.path is posixpath:
# normcase on posix is NOP. Optimize it away from the loop.
for name in names:
if match(name):
result.append(name)
else:
for name in names:
if match(os.path.normcase(name)):
result.append(name)
return result
def fnmatchcase(name, pat):
"""Test whether FILENAME matches PATTERN, including case.
This is a version of fnmatch() which doesn't case-normalize
its arguments.
"""
match = _compile_pattern(pat)
return match(name) is not None
def translate(pat):
"""Translate a shell PATTERN to a regular expression.
There is no way to quote meta-characters.
"""
i, n = 0, len(pat)
res = ''
while i < n:
c = pat[i]
i = i+1
if c == '*':
res = res + '.*'
elif c == '?':
res = res + '.'
elif c == '[':
j = i
if j < n and pat[j] == '!':
j = j+1
if j < n and pat[j] == ']':
j = j+1
while j < n and pat[j] != ']':
j = j+1
if j >= n:
res = res + '\\['
else:
stuff = pat[i:j].replace('\\','\\\\')
i = j+1
if stuff[0] == '!':
stuff = '^' + stuff[1:]
elif stuff[0] == '^':
stuff = '\\' + stuff
res = '%s[%s]' % (res, stuff)
else:
res = res + re.escape(c)
return res + '\Z(?ms)'