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