"""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 os import posixpath import re import functools __all__ = ["filter", "fnmatch", "fnmatchcase", "translate"] # Build a thread-safe incrementing counter to help create unique regexp group # names across calls. from itertools import count _nextgroupnum = count().__next__ del count 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). """ name = os.path.normcase(name) pat = os.path.normcase(pat) return fnmatchcase(name, pat) @functools.lru_cache(maxsize=256, typed=True) def _compile_pattern(pat): 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) return re.compile(res).match def filter(names, pat): """Construct a list from those elements of the iterable NAMES that match PAT.""" 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. """ STAR = object() res = [] add = res.append i, n = 0, len(pat) while i < n: c = pat[i] i = i+1 if c == '*': # compress consecutive `*` into one if (not res) or res[-1] is not STAR: add(STAR) elif c == '?': add('.') 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: add('\\[') else: stuff = pat[i:j] if '-' not in stuff: stuff = stuff.replace('\\', r'\\') else: chunks = [] k = i+2 if pat[i] == '!' else i+1 while True: k = pat.find('-', k, j) if k < 0: break chunks.append(pat[i:k]) i = k+1 k = k+3 chunk = pat[i:j] if chunk: chunks.append(chunk) else: chunks[-1] += '-' # Remove empty ranges -- invalid in RE. for k in range(len(chunks)-1, 0, -1): if chunks[k-1][-1] > chunks[k][0]: chunks[k-1] = chunks[k-1][:-1] + chunks[k][1:] del chunks[k] # Escape backslashes and hyphens for set difference (--). # Hyphens that create ranges shouldn't be escaped. stuff = '-'.join(s.replace('\\', r'\\').replace('-', r'\-') for s in chunks) # Escape set operations (&&, ~~ and ||). stuff = re.sub(r'([&~|])', r'\\\1', stuff) i = j+1 if not stuff: # Empty range: never match. add('(?!)') elif stuff == '!': # Negated empty range: match any character. add('.') else: if stuff[0] == '!': stuff = '^' + stuff[1:] elif stuff[0] in ('^', '['): stuff = '\\' + stuff add(f'[{stuff}]') else: add(re.escape(c)) assert i == n # Deal with STARs. inp = res res = [] add = res.append i, n = 0, len(inp) # Fixed pieces at the start? while i < n and inp[i] is not STAR: add(inp[i]) i += 1 # Now deal with STAR fixed STAR fixed ... # For an interior `STAR fixed` pairing, we want to do a minimal # .*? match followed by `fixed`, with no possibility of backtracking. # We can't spell that directly, but can trick it into working by matching # .*?fixed # in a lookahead assertion, save the matched part in a group, then # consume that group via a backreference. If the overall match fails, # the lookahead assertion won't try alternatives. So the translation is: # (?=(?P<name>.*?fixed))(?P=name) # Group names are created as needed: g0, g1, g2, ... # The numbers are obtained from _nextgroupnum() to ensure they're unique # across calls and across threads. This is because people rely on the # undocumented ability to join multiple translate() results together via # "|" to build large regexps matching "one of many" shell patterns. while i < n: assert inp[i] is STAR i += 1 if i == n: add(".*") break assert inp[i] is not STAR fixed = [] while i < n and inp[i] is not STAR: fixed.append(inp[i]) i += 1 fixed = "".join(fixed) if i == n: add(".*") add(fixed) else: groupnum = _nextgroupnum() add(f"(?=(?P<g{groupnum}>.*?{fixed}))(?P=g{groupnum})") assert i == n res = "".join(res) return fr'(?s:{res})\Z'