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pythonGH-116380: Move pathlib globbing implementation into `pathlib._…
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…glob` (python#118562)

Moving this code under the `pathlib` package makes it quite a lot easier
to backport in the `pathlib-abc` PyPI package. It was a bit foolish of me
to add it to `glob` in the first place.

Also add `translate()` to `__all__` in `glob`. This function is new in
3.13, so there's no NEWS needed.
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@barneygale
barneygale authored May 3, 2024
1 parent 37d0950 commit a40f557
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306 changes: 3 additions & 303 deletions Lib/glob.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2,15 +2,14 @@

import contextlib
import os
import re
import fnmatch
import functools
import itertools
import operator
import stat
import sys

__all__ = ["glob", "iglob", "escape"]
from pathlib._glob import translate, magic_check, magic_check_bytes

__all__ = ["glob", "iglob", "escape", "translate"]

def glob(pathname, *, root_dir=None, dir_fd=None, recursive=False,
include_hidden=False):
Expand Down Expand Up @@ -226,9 +225,6 @@ def _join(dirname, basename):
return dirname or basename
return os.path.join(dirname, basename)

magic_check = re.compile('([*?[])')
magic_check_bytes = re.compile(b'([*?[])')

def has_magic(s):
if isinstance(s, bytes):
match = magic_check_bytes.search(s)
Expand Down Expand Up @@ -258,300 +254,4 @@ def escape(pathname):
return drive + pathname


_special_parts = ('', '.', '..')
_dir_open_flags = os.O_RDONLY | getattr(os, 'O_DIRECTORY', 0)
_no_recurse_symlinks = object()


def translate(pat, *, recursive=False, include_hidden=False, seps=None):
"""Translate a pathname with shell wildcards to a regular expression.
If `recursive` is true, the pattern segment '**' will match any number of
path segments.
If `include_hidden` is true, wildcards can match path segments beginning
with a dot ('.').
If a sequence of separator characters is given to `seps`, they will be
used to split the pattern into segments and match path separators. If not
given, os.path.sep and os.path.altsep (where available) are used.
"""
if not seps:
if os.path.altsep:
seps = (os.path.sep, os.path.altsep)
else:
seps = os.path.sep
escaped_seps = ''.join(map(re.escape, seps))
any_sep = f'[{escaped_seps}]' if len(seps) > 1 else escaped_seps
not_sep = f'[^{escaped_seps}]'
if include_hidden:
one_last_segment = f'{not_sep}+'
one_segment = f'{one_last_segment}{any_sep}'
any_segments = f'(?:.+{any_sep})?'
any_last_segments = '.*'
else:
one_last_segment = f'[^{escaped_seps}.]{not_sep}*'
one_segment = f'{one_last_segment}{any_sep}'
any_segments = f'(?:{one_segment})*'
any_last_segments = f'{any_segments}(?:{one_last_segment})?'

results = []
parts = re.split(any_sep, pat)
last_part_idx = len(parts) - 1
for idx, part in enumerate(parts):
if part == '*':
results.append(one_segment if idx < last_part_idx else one_last_segment)
elif recursive and part == '**':
if idx < last_part_idx:
if parts[idx + 1] != '**':
results.append(any_segments)
else:
results.append(any_last_segments)
else:
if part:
if not include_hidden and part[0] in '*?':
results.append(r'(?!\.)')
results.extend(fnmatch._translate(part, f'{not_sep}*', not_sep))
if idx < last_part_idx:
results.append(any_sep)
res = ''.join(results)
return fr'(?s:{res})\Z'


@functools.lru_cache(maxsize=512)
def _compile_pattern(pat, sep, case_sensitive, recursive=True):
"""Compile given glob pattern to a re.Pattern object (observing case
sensitivity)."""
flags = re.NOFLAG if case_sensitive else re.IGNORECASE
regex = translate(pat, recursive=recursive, include_hidden=True, seps=sep)
return re.compile(regex, flags=flags).match


class _Globber:
"""Class providing shell-style pattern matching and globbing.
"""

def __init__(self, sep, case_sensitive, case_pedantic=False, recursive=False):
self.sep = sep
self.case_sensitive = case_sensitive
self.case_pedantic = case_pedantic
self.recursive = recursive

# Low-level methods

lstat = staticmethod(os.lstat)
scandir = staticmethod(os.scandir)
parse_entry = operator.attrgetter('path')
concat_path = operator.add

if os.name == 'nt':
@staticmethod
def add_slash(pathname):
tail = os.path.splitroot(pathname)[2]
if not tail or tail[-1] in '\\/':
return pathname
return f'{pathname}\\'
else:
@staticmethod
def add_slash(pathname):
if not pathname or pathname[-1] == '/':
return pathname
return f'{pathname}/'

# High-level methods

def compile(self, pat):
return _compile_pattern(pat, self.sep, self.case_sensitive, self.recursive)

def selector(self, parts):
"""Returns a function that selects from a given path, walking and
filtering according to the glob-style pattern parts in *parts*.
"""
if not parts:
return self.select_exists
part = parts.pop()
if self.recursive and part == '**':
selector = self.recursive_selector
elif part in _special_parts:
selector = self.special_selector
elif not self.case_pedantic and magic_check.search(part) is None:
selector = self.literal_selector
else:
selector = self.wildcard_selector
return selector(part, parts)

def special_selector(self, part, parts):
"""Returns a function that selects special children of the given path.
"""
select_next = self.selector(parts)

def select_special(path, exists=False):
path = self.concat_path(self.add_slash(path), part)
return select_next(path, exists)
return select_special

def literal_selector(self, part, parts):
"""Returns a function that selects a literal descendant of a path.
"""

# Optimization: consume and join any subsequent literal parts here,
# rather than leaving them for the next selector. This reduces the
# number of string concatenation operations and calls to add_slash().
while parts and magic_check.search(parts[-1]) is None:
part += self.sep + parts.pop()

select_next = self.selector(parts)

def select_literal(path, exists=False):
path = self.concat_path(self.add_slash(path), part)
return select_next(path, exists=False)
return select_literal

def wildcard_selector(self, part, parts):
"""Returns a function that selects direct children of a given path,
filtering by pattern.
"""

match = None if part == '*' else self.compile(part)
dir_only = bool(parts)
if dir_only:
select_next = self.selector(parts)

def select_wildcard(path, exists=False):
try:
# We must close the scandir() object before proceeding to
# avoid exhausting file descriptors when globbing deep trees.
with self.scandir(path) as scandir_it:
entries = list(scandir_it)
except OSError:
pass
else:
for entry in entries:
if match is None or match(entry.name):
if dir_only:
try:
if not entry.is_dir():
continue
except OSError:
continue
entry_path = self.parse_entry(entry)
if dir_only:
yield from select_next(entry_path, exists=True)
else:
yield entry_path
return select_wildcard

def recursive_selector(self, part, parts):
"""Returns a function that selects a given path and all its children,
recursively, filtering by pattern.
"""
# Optimization: consume following '**' parts, which have no effect.
while parts and parts[-1] == '**':
parts.pop()

# Optimization: consume and join any following non-special parts here,
# rather than leaving them for the next selector. They're used to
# build a regular expression, which we use to filter the results of
# the recursive walk. As a result, non-special pattern segments
# following a '**' wildcard don't require additional filesystem access
# to expand.
follow_symlinks = self.recursive is not _no_recurse_symlinks
if follow_symlinks:
while parts and parts[-1] not in _special_parts:
part += self.sep + parts.pop()

match = None if part == '**' else self.compile(part)
dir_only = bool(parts)
select_next = self.selector(parts)

def select_recursive(path, exists=False):
path = self.add_slash(path)
match_pos = len(str(path))
if match is None or match(str(path), match_pos):
yield from select_next(path, exists)
stack = [path]
while stack:
yield from select_recursive_step(stack, match_pos)

def select_recursive_step(stack, match_pos):
path = stack.pop()
try:
# We must close the scandir() object before proceeding to
# avoid exhausting file descriptors when globbing deep trees.
with self.scandir(path) as scandir_it:
entries = list(scandir_it)
except OSError:
pass
else:
for entry in entries:
is_dir = False
try:
if entry.is_dir(follow_symlinks=follow_symlinks):
is_dir = True
except OSError:
pass

if is_dir or not dir_only:
entry_path = self.parse_entry(entry)
if match is None or match(str(entry_path), match_pos):
if dir_only:
yield from select_next(entry_path, exists=True)
else:
# Optimization: directly yield the path if this is
# last pattern part.
yield entry_path
if is_dir:
stack.append(entry_path)

return select_recursive

def select_exists(self, path, exists=False):
"""Yields the given path, if it exists.
"""
if exists:
# Optimization: this path is already known to exist, e.g. because
# it was returned from os.scandir(), so we skip calling lstat().
yield path
else:
try:
self.lstat(path)
yield path
except OSError:
pass

@classmethod
def walk(cls, root, top_down, on_error, follow_symlinks):
"""Walk the directory tree from the given root, similar to os.walk().
"""
paths = [root]
while paths:
path = paths.pop()
if isinstance(path, tuple):
yield path
continue
try:
with cls.scandir(path) as scandir_it:
dirnames = []
filenames = []
if not top_down:
paths.append((path, dirnames, filenames))
for entry in scandir_it:
name = entry.name
try:
if entry.is_dir(follow_symlinks=follow_symlinks):
if not top_down:
paths.append(cls.parse_entry(entry))
dirnames.append(name)
else:
filenames.append(name)
except OSError:
filenames.append(name)
except OSError as error:
if on_error is not None:
on_error(error)
else:
if top_down:
yield path, dirnames, filenames
if dirnames:
prefix = cls.add_slash(path)
paths += [cls.concat_path(prefix, d) for d in reversed(dirnames)]
5 changes: 2 additions & 3 deletions Lib/pathlib/__init__.py
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,6 @@
operating systems.
"""

import glob
import io
import ntpath
import operator
Expand All @@ -25,7 +24,7 @@
except ImportError:
grp = None

from . import _abc
from . import _abc, _glob


__all__ = [
Expand Down Expand Up @@ -113,7 +112,7 @@ class PurePath(_abc.PurePathBase):
'_hash',
)
parser = os.path
_globber = glob._Globber
_globber = _glob.Globber

def __new__(cls, *args, **kwargs):
"""Construct a PurePath from one or several strings and or existing
Expand Down
7 changes: 4 additions & 3 deletions Lib/pathlib/_abc.py
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Original file line number Diff line number Diff line change
Expand Up @@ -12,11 +12,12 @@
"""

import functools
import glob
import operator
from errno import ENOENT, ENOTDIR, EBADF, ELOOP, EINVAL
from stat import S_ISDIR, S_ISLNK, S_ISREG, S_ISSOCK, S_ISBLK, S_ISCHR, S_ISFIFO

from . import _glob

#
# Internals
#
Expand All @@ -43,7 +44,7 @@ def _is_case_sensitive(parser):
return parser.normcase('Aa') == 'Aa'


class Globber(glob._Globber):
class Globber(_glob.Globber):
lstat = operator.methodcaller('lstat')
add_slash = operator.methodcaller('joinpath', '')

Expand Down Expand Up @@ -692,7 +693,7 @@ def _glob_selector(self, parts, case_sensitive, recurse_symlinks):
# know the case sensitivity of the underlying filesystem, so we
# must use scandir() for everything, including non-wildcard parts.
case_pedantic = True
recursive = True if recurse_symlinks else glob._no_recurse_symlinks
recursive = True if recurse_symlinks else _glob.no_recurse_symlinks
globber = self._globber(self.parser.sep, case_sensitive, case_pedantic, recursive)
return globber.selector(parts)

Expand Down
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