Viewing file:  glob.py (3.01 KB) -rw-r--r--
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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.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 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<set>[\[].*?[\]])|([\[][^\]]*$)', pattern)
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