import os import re _default_seps = os.sep + str(os.altsep) * bool(os.altsep) class Translator: """ >>> Translator('xyz') Traceback (most recent call last): ... AssertionError: Invalid separators >>> Translator('') Traceback (most recent call last): ... AssertionError: Invalid separators """ seps: str def __init__(self, seps: str = _default_seps): assert seps and set(seps) <= set(_default_seps), "Invalid separators" self.seps = seps def translate(self, pattern): """ Given a glob pattern, produce a regex that matches it. """ return self.extend(self.match_dirs(self.translate_core(pattern))) def extend(self, pattern): r""" Extend regex for pattern-wide concerns. Apply '(?s:)' to create a non-matching group that matches newlines (valid on Unix). Append '\Z' to imply fullmatch even when match is used. """ return rf'(?s:{pattern})\Z' def match_dirs(self, pattern): """ Ensure that zipfile.Path directory names are matched. zipfile.Path directory names always end in a slash. """ return rf'{pattern}[/]?' def translate_core(self, pattern): r""" Given a glob pattern, produce a regex that matches it. >>> t = Translator() >>> t.translate_core('*.txt').replace('\\\\', '') '[^/]*\\.txt' >>> t.translate_core('a?txt') 'a[^/]txt' >>> t.translate_core('**/*').replace('\\\\', '') '.*/[^/][^/]*' """ self.restrict_rglob(pattern) return ''.join(map(self.replace, separate(self.star_not_empty(pattern)))) def replace(self, match): """ Perform the replacements for a match from :func:`separate`. """ return match.group('set') or ( re.escape(match.group(0)) .replace('\\*\\*', r'.*') .replace('\\*', rf'[^{re.escape(self.seps)}]*') .replace('\\?', r'[^/]') ) def restrict_rglob(self, pattern): """ Raise ValueError if ** appears in anything but a full path segment. >>> Translator().translate('**foo') Traceback (most recent call last): ... ValueError: ** must appear alone in a path segment """ seps_pattern = rf'[{re.escape(self.seps)}]+' segments = re.split(seps_pattern, pattern) if any('**' in segment and segment != '**' for segment in segments): raise ValueError("** must appear alone in a path segment") def star_not_empty(self, pattern): """ Ensure that * will not match an empty segment. """ def handle_segment(match): segment = match.group(0) return '?*' if segment == '*' else segment not_seps_pattern = rf'[^{re.escape(self.seps)}]+' return re.sub(not_seps_pattern, handle_segment, pattern) def separate(pattern): """ Separate out character sets to avoid translating their contents. >>> [m.group(0) for m in separate('*.txt')] ['*.txt'] >>> [m.group(0) for m in separate('a[?]txt')] ['a', '[?]', 'txt'] """ return re.finditer(r'([^\[]+)|(?P[\[].*?[\]])|([\[][^\]]*$)', pattern)