cpython/Lib/pathlib/_abc.py

909 lines
32 KiB
Python

"""
Abstract base classes for rich path objects.
This module is published as a PyPI package called "pathlib-abc".
This module is also a *PRIVATE* part of the Python standard library, where
it's developed alongside pathlib. If it finds success and maturity as a PyPI
package, it could become a public part of the standard library.
Two base classes are defined here -- PurePathBase and PathBase -- that
resemble pathlib's PurePath and Path respectively.
"""
import functools
import operator
import posixpath
from glob import _GlobberBase, _no_recurse_symlinks
from stat import S_ISDIR, S_ISLNK, S_ISREG, S_ISSOCK, S_ISBLK, S_ISCHR, S_ISFIFO
from ._os import UnsupportedOperation, copyfileobj
@functools.cache
def _is_case_sensitive(parser):
return parser.normcase('Aa') == 'Aa'
class ParserBase:
"""Base class for path parsers, which do low-level path manipulation.
Path parsers provide a subset of the os.path API, specifically those
functions needed to provide PurePathBase functionality. Each PurePathBase
subclass references its path parser via a 'parser' class attribute.
Every method in this base class raises an UnsupportedOperation exception.
"""
@classmethod
def _unsupported_msg(cls, attribute):
return f"{cls.__name__}.{attribute} is unsupported"
@property
def sep(self):
"""The character used to separate path components."""
raise UnsupportedOperation(self._unsupported_msg('sep'))
def join(self, path, *paths):
"""Join path segments."""
raise UnsupportedOperation(self._unsupported_msg('join()'))
def split(self, path):
"""Split the path into a pair (head, tail), where *head* is everything
before the final path separator, and *tail* is everything after.
Either part may be empty.
"""
raise UnsupportedOperation(self._unsupported_msg('split()'))
def splitdrive(self, path):
"""Split the path into a 2-item tuple (drive, tail), where *drive* is
a device name or mount point, and *tail* is everything after the
drive. Either part may be empty."""
raise UnsupportedOperation(self._unsupported_msg('splitdrive()'))
def splitext(self, path):
"""Split the path into a pair (root, ext), where *ext* is empty or
begins with a begins with a period and contains at most one period,
and *root* is everything before the extension."""
raise UnsupportedOperation(self._unsupported_msg('splitext()'))
def normcase(self, path):
"""Normalize the case of the path."""
raise UnsupportedOperation(self._unsupported_msg('normcase()'))
def isabs(self, path):
"""Returns whether the path is absolute, i.e. unaffected by the
current directory or drive."""
raise UnsupportedOperation(self._unsupported_msg('isabs()'))
class PathGlobber(_GlobberBase):
"""
Class providing shell-style globbing for path objects.
"""
lexists = operator.methodcaller('exists', follow_symlinks=False)
add_slash = operator.methodcaller('joinpath', '')
@staticmethod
def scandir(path):
"""Emulates os.scandir(), which returns an object that can be used as
a context manager. This method is called by walk() and glob().
"""
import contextlib
return contextlib.nullcontext(path.iterdir())
@staticmethod
def concat_path(path, text):
"""Appends text to the given path."""
return path.with_segments(path._raw_path + text)
@staticmethod
def parse_entry(entry):
"""Returns the path of an entry yielded from scandir()."""
return entry
class PurePathBase:
"""Base class for pure path objects.
This class *does not* provide several magic methods that are defined in
its subclass PurePath. They are: __fspath__, __bytes__, __reduce__,
__hash__, __eq__, __lt__, __le__, __gt__, __ge__. Its initializer and path
joining methods accept only strings, not os.PathLike objects more broadly.
"""
__slots__ = (
# The `_raw_path` slot store a joined string path. This is set in the
# `__init__()` method.
'_raw_path',
# The '_resolving' slot stores a boolean indicating whether the path
# is being processed by `PathBase.resolve()`. This prevents duplicate
# work from occurring when `resolve()` calls `stat()` or `readlink()`.
'_resolving',
)
parser = ParserBase()
_globber = PathGlobber
def __init__(self, path, *paths):
self._raw_path = self.parser.join(path, *paths) if paths else path
if not isinstance(self._raw_path, str):
raise TypeError(
f"path should be a str, not {type(self._raw_path).__name__!r}")
self._resolving = False
def with_segments(self, *pathsegments):
"""Construct a new path object from any number of path-like objects.
Subclasses may override this method to customize how new path objects
are created from methods like `iterdir()`.
"""
return type(self)(*pathsegments)
def __str__(self):
"""Return the string representation of the path, suitable for
passing to system calls."""
return self._raw_path
def as_posix(self):
"""Return the string representation of the path with forward (/)
slashes."""
return str(self).replace(self.parser.sep, '/')
@property
def drive(self):
"""The drive prefix (letter or UNC path), if any."""
return self.parser.splitdrive(self.anchor)[0]
@property
def root(self):
"""The root of the path, if any."""
return self.parser.splitdrive(self.anchor)[1]
@property
def anchor(self):
"""The concatenation of the drive and root, or ''."""
return self._stack[0]
@property
def name(self):
"""The final path component, if any."""
return self.parser.split(self._raw_path)[1]
@property
def suffix(self):
"""
The final component's last suffix, if any.
This includes the leading period. For example: '.txt'
"""
return self.parser.splitext(self.name)[1]
@property
def suffixes(self):
"""
A list of the final component's suffixes, if any.
These include the leading periods. For example: ['.tar', '.gz']
"""
split = self.parser.splitext
stem, suffix = split(self.name)
suffixes = []
while suffix:
suffixes.append(suffix)
stem, suffix = split(stem)
return suffixes[::-1]
@property
def stem(self):
"""The final path component, minus its last suffix."""
return self.parser.splitext(self.name)[0]
def with_name(self, name):
"""Return a new path with the file name changed."""
split = self.parser.split
if split(name)[0]:
raise ValueError(f"Invalid name {name!r}")
return self.with_segments(split(self._raw_path)[0], name)
def with_stem(self, stem):
"""Return a new path with the stem changed."""
suffix = self.suffix
if not suffix:
return self.with_name(stem)
elif not stem:
# If the suffix is non-empty, we can't make the stem empty.
raise ValueError(f"{self!r} has a non-empty suffix")
else:
return self.with_name(stem + suffix)
def with_suffix(self, suffix):
"""Return a new path with the file suffix changed. If the path
has no suffix, add given suffix. If the given suffix is an empty
string, remove the suffix from the path.
"""
stem = self.stem
if not stem:
# If the stem is empty, we can't make the suffix non-empty.
raise ValueError(f"{self!r} has an empty name")
elif suffix and not suffix.startswith('.'):
raise ValueError(f"Invalid suffix {suffix!r}")
else:
return self.with_name(stem + suffix)
def relative_to(self, other, *, walk_up=False):
"""Return the relative path to another path identified by the passed
arguments. If the operation is not possible (because this is not
related to the other path), raise ValueError.
The *walk_up* parameter controls whether `..` may be used to resolve
the path.
"""
if not isinstance(other, PurePathBase):
other = self.with_segments(other)
anchor0, parts0 = self._stack
anchor1, parts1 = other._stack
if anchor0 != anchor1:
raise ValueError(f"{self._raw_path!r} and {other._raw_path!r} have different anchors")
while parts0 and parts1 and parts0[-1] == parts1[-1]:
parts0.pop()
parts1.pop()
for part in parts1:
if not part or part == '.':
pass
elif not walk_up:
raise ValueError(f"{self._raw_path!r} is not in the subpath of {other._raw_path!r}")
elif part == '..':
raise ValueError(f"'..' segment in {other._raw_path!r} cannot be walked")
else:
parts0.append('..')
return self.with_segments('', *reversed(parts0))
def is_relative_to(self, other):
"""Return True if the path is relative to another path or False.
"""
if not isinstance(other, PurePathBase):
other = self.with_segments(other)
anchor0, parts0 = self._stack
anchor1, parts1 = other._stack
if anchor0 != anchor1:
return False
while parts0 and parts1 and parts0[-1] == parts1[-1]:
parts0.pop()
parts1.pop()
for part in parts1:
if part and part != '.':
return False
return True
@property
def parts(self):
"""An object providing sequence-like access to the
components in the filesystem path."""
anchor, parts = self._stack
if anchor:
parts.append(anchor)
return tuple(reversed(parts))
def joinpath(self, *pathsegments):
"""Combine this path with one or several arguments, and return a
new path representing either a subpath (if all arguments are relative
paths) or a totally different path (if one of the arguments is
anchored).
"""
return self.with_segments(self._raw_path, *pathsegments)
def __truediv__(self, key):
try:
return self.with_segments(self._raw_path, key)
except TypeError:
return NotImplemented
def __rtruediv__(self, key):
try:
return self.with_segments(key, self._raw_path)
except TypeError:
return NotImplemented
@property
def _stack(self):
"""
Split the path into a 2-tuple (anchor, parts), where *anchor* is the
uppermost parent of the path (equivalent to path.parents[-1]), and
*parts* is a reversed list of parts following the anchor.
"""
split = self.parser.split
path = self._raw_path
parent, name = split(path)
names = []
while path != parent:
names.append(name)
path = parent
parent, name = split(path)
return path, names
@property
def parent(self):
"""The logical parent of the path."""
path = self._raw_path
parent = self.parser.split(path)[0]
if path != parent:
parent = self.with_segments(parent)
parent._resolving = self._resolving
return parent
return self
@property
def parents(self):
"""A sequence of this path's logical parents."""
split = self.parser.split
path = self._raw_path
parent = split(path)[0]
parents = []
while path != parent:
parents.append(self.with_segments(parent))
path = parent
parent = split(path)[0]
return tuple(parents)
def is_absolute(self):
"""True if the path is absolute (has both a root and, if applicable,
a drive)."""
return self.parser.isabs(self._raw_path)
@property
def _pattern_str(self):
"""The path expressed as a string, for use in pattern-matching."""
return str(self)
def match(self, path_pattern, *, case_sensitive=None):
"""
Return True if this path matches the given pattern. If the pattern is
relative, matching is done from the right; otherwise, the entire path
is matched. The recursive wildcard '**' is *not* supported by this
method.
"""
if not isinstance(path_pattern, PurePathBase):
path_pattern = self.with_segments(path_pattern)
if case_sensitive is None:
case_sensitive = _is_case_sensitive(self.parser)
sep = path_pattern.parser.sep
path_parts = self.parts[::-1]
pattern_parts = path_pattern.parts[::-1]
if not pattern_parts:
raise ValueError("empty pattern")
if len(path_parts) < len(pattern_parts):
return False
if len(path_parts) > len(pattern_parts) and path_pattern.anchor:
return False
globber = self._globber(sep, case_sensitive)
for path_part, pattern_part in zip(path_parts, pattern_parts):
match = globber.compile(pattern_part)
if match(path_part) is None:
return False
return True
def full_match(self, pattern, *, case_sensitive=None):
"""
Return True if this path matches the given glob-style pattern. The
pattern is matched against the entire path.
"""
if not isinstance(pattern, PurePathBase):
pattern = self.with_segments(pattern)
if case_sensitive is None:
case_sensitive = _is_case_sensitive(self.parser)
globber = self._globber(pattern.parser.sep, case_sensitive, recursive=True)
match = globber.compile(pattern._pattern_str)
return match(self._pattern_str) is not None
class PathBase(PurePathBase):
"""Base class for concrete path objects.
This class provides dummy implementations for many methods that derived
classes can override selectively; the default implementations raise
UnsupportedOperation. The most basic methods, such as stat() and open(),
directly raise UnsupportedOperation; these basic methods are called by
other methods such as is_dir() and read_text().
The Path class derives this class to implement local filesystem paths.
Users may derive their own classes to implement virtual filesystem paths,
such as paths in archive files or on remote storage systems.
"""
__slots__ = ()
# Maximum number of symlinks to follow in resolve()
_max_symlinks = 40
@classmethod
def _unsupported_msg(cls, attribute):
return f"{cls.__name__}.{attribute} is unsupported"
def stat(self, *, follow_symlinks=True):
"""
Return the result of the stat() system call on this path, like
os.stat() does.
"""
raise UnsupportedOperation(self._unsupported_msg('stat()'))
def lstat(self):
"""
Like stat(), except if the path points to a symlink, the symlink's
status information is returned, rather than its target's.
"""
return self.stat(follow_symlinks=False)
# Convenience functions for querying the stat results
def exists(self, *, follow_symlinks=True):
"""
Whether this path exists.
This method normally follows symlinks; to check whether a symlink exists,
add the argument follow_symlinks=False.
"""
try:
self.stat(follow_symlinks=follow_symlinks)
except (OSError, ValueError):
return False
return True
def is_dir(self, *, follow_symlinks=True):
"""
Whether this path is a directory.
"""
try:
return S_ISDIR(self.stat(follow_symlinks=follow_symlinks).st_mode)
except (OSError, ValueError):
return False
def is_file(self, *, follow_symlinks=True):
"""
Whether this path is a regular file (also True for symlinks pointing
to regular files).
"""
try:
return S_ISREG(self.stat(follow_symlinks=follow_symlinks).st_mode)
except (OSError, ValueError):
return False
def is_mount(self):
"""
Check if this path is a mount point
"""
# Need to exist and be a dir
if not self.exists() or not self.is_dir():
return False
try:
parent_dev = self.parent.stat().st_dev
except OSError:
return False
dev = self.stat().st_dev
if dev != parent_dev:
return True
ino = self.stat().st_ino
parent_ino = self.parent.stat().st_ino
return ino == parent_ino
def is_symlink(self):
"""
Whether this path is a symbolic link.
"""
try:
return S_ISLNK(self.lstat().st_mode)
except (OSError, ValueError):
return False
def is_junction(self):
"""
Whether this path is a junction.
"""
# Junctions are a Windows-only feature, not present in POSIX nor the
# majority of virtual filesystems. There is no cross-platform idiom
# to check for junctions (using stat().st_mode).
return False
def is_block_device(self):
"""
Whether this path is a block device.
"""
try:
return S_ISBLK(self.stat().st_mode)
except (OSError, ValueError):
return False
def is_char_device(self):
"""
Whether this path is a character device.
"""
try:
return S_ISCHR(self.stat().st_mode)
except (OSError, ValueError):
return False
def is_fifo(self):
"""
Whether this path is a FIFO.
"""
try:
return S_ISFIFO(self.stat().st_mode)
except (OSError, ValueError):
return False
def is_socket(self):
"""
Whether this path is a socket.
"""
try:
return S_ISSOCK(self.stat().st_mode)
except (OSError, ValueError):
return False
def samefile(self, other_path):
"""Return whether other_path is the same or not as this file
(as returned by os.path.samefile()).
"""
st = self.stat()
try:
other_st = other_path.stat()
except AttributeError:
other_st = self.with_segments(other_path).stat()
return (st.st_ino == other_st.st_ino and
st.st_dev == other_st.st_dev)
def _samefile_safe(self, other_path):
"""
Like samefile(), but returns False rather than raising OSError.
"""
try:
return self.samefile(other_path)
except (OSError, ValueError):
return False
def open(self, mode='r', buffering=-1, encoding=None,
errors=None, newline=None):
"""
Open the file pointed to by this path and return a file object, as
the built-in open() function does.
"""
raise UnsupportedOperation(self._unsupported_msg('open()'))
def read_bytes(self):
"""
Open the file in bytes mode, read it, and close the file.
"""
with self.open(mode='rb') as f:
return f.read()
def read_text(self, encoding=None, errors=None, newline=None):
"""
Open the file in text mode, read it, and close the file.
"""
with self.open(mode='r', encoding=encoding, errors=errors, newline=newline) as f:
return f.read()
def write_bytes(self, data):
"""
Open the file in bytes mode, write to it, and close the file.
"""
# type-check for the buffer interface before truncating the file
view = memoryview(data)
with self.open(mode='wb') as f:
return f.write(view)
def write_text(self, data, encoding=None, errors=None, newline=None):
"""
Open the file in text mode, write to it, and close the file.
"""
if not isinstance(data, str):
raise TypeError('data must be str, not %s' %
data.__class__.__name__)
with self.open(mode='w', encoding=encoding, errors=errors, newline=newline) as f:
return f.write(data)
def iterdir(self):
"""Yield path objects of the directory contents.
The children are yielded in arbitrary order, and the
special entries '.' and '..' are not included.
"""
raise UnsupportedOperation(self._unsupported_msg('iterdir()'))
def _glob_selector(self, parts, case_sensitive, recurse_symlinks):
if case_sensitive is None:
case_sensitive = _is_case_sensitive(self.parser)
case_pedantic = False
else:
# The user has expressed a case sensitivity choice, but we don't
# 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 _no_recurse_symlinks
globber = self._globber(self.parser.sep, case_sensitive, case_pedantic, recursive)
return globber.selector(parts)
def glob(self, pattern, *, case_sensitive=None, recurse_symlinks=True):
"""Iterate over this subtree and yield all existing files (of any
kind, including directories) matching the given relative pattern.
"""
if not isinstance(pattern, PurePathBase):
pattern = self.with_segments(pattern)
anchor, parts = pattern._stack
if anchor:
raise NotImplementedError("Non-relative patterns are unsupported")
select = self._glob_selector(parts, case_sensitive, recurse_symlinks)
return select(self)
def rglob(self, pattern, *, case_sensitive=None, recurse_symlinks=True):
"""Recursively yield all existing files (of any kind, including
directories) matching the given relative pattern, anywhere in
this subtree.
"""
if not isinstance(pattern, PurePathBase):
pattern = self.with_segments(pattern)
pattern = '**' / pattern
return self.glob(pattern, case_sensitive=case_sensitive, recurse_symlinks=recurse_symlinks)
def walk(self, top_down=True, on_error=None, follow_symlinks=False):
"""Walk the directory tree from this directory, similar to os.walk()."""
paths = [self]
while paths:
path = paths.pop()
if isinstance(path, tuple):
yield path
continue
dirnames = []
filenames = []
if not top_down:
paths.append((path, dirnames, filenames))
try:
for child in path.iterdir():
try:
if child.is_dir(follow_symlinks=follow_symlinks):
if not top_down:
paths.append(child)
dirnames.append(child.name)
else:
filenames.append(child.name)
except OSError:
filenames.append(child.name)
except OSError as error:
if on_error is not None:
on_error(error)
if not top_down:
while not isinstance(paths.pop(), tuple):
pass
continue
if top_down:
yield path, dirnames, filenames
paths += [path.joinpath(d) for d in reversed(dirnames)]
def absolute(self):
"""Return an absolute version of this path
No normalization or symlink resolution is performed.
Use resolve() to resolve symlinks and remove '..' segments.
"""
raise UnsupportedOperation(self._unsupported_msg('absolute()'))
@classmethod
def cwd(cls):
"""Return a new path pointing to the current working directory."""
# We call 'absolute()' rather than using 'os.getcwd()' directly to
# enable users to replace the implementation of 'absolute()' in a
# subclass and benefit from the new behaviour here. This works because
# os.path.abspath('.') == os.getcwd().
return cls('').absolute()
def expanduser(self):
""" Return a new path with expanded ~ and ~user constructs
(as returned by os.path.expanduser)
"""
raise UnsupportedOperation(self._unsupported_msg('expanduser()'))
@classmethod
def home(cls):
"""Return a new path pointing to expanduser('~').
"""
return cls("~").expanduser()
def readlink(self):
"""
Return the path to which the symbolic link points.
"""
raise UnsupportedOperation(self._unsupported_msg('readlink()'))
readlink._supported = False
def resolve(self, strict=False):
"""
Make the path absolute, resolving all symlinks on the way and also
normalizing it.
"""
if self._resolving:
return self
def getcwd():
return str(self.with_segments().absolute())
if strict or getattr(self.readlink, '_supported', True):
def lstat(path_str):
path = self.with_segments(path_str)
path._resolving = True
return path.lstat()
def readlink(path_str):
path = self.with_segments(path_str)
path._resolving = True
return str(path.readlink())
else:
# If the user has *not* overridden the `readlink()` method, then
# symlinks are unsupported and (in non-strict mode) we can improve
# performance by not calling `path.lstat()`.
def skip(path_str):
# This exception will be internally consumed by `_realpath()`.
raise OSError("Operation skipped.")
lstat = readlink = skip
return self.with_segments(posixpath._realpath(
str(self), strict, self.parser.sep,
getcwd=getcwd, lstat=lstat, readlink=readlink,
maxlinks=self._max_symlinks))
def symlink_to(self, target, target_is_directory=False):
"""
Make this path a symlink pointing to the target path.
Note the order of arguments (link, target) is the reverse of os.symlink.
"""
raise UnsupportedOperation(self._unsupported_msg('symlink_to()'))
def hardlink_to(self, target):
"""
Make this path a hard link pointing to the same file as *target*.
Note the order of arguments (self, target) is the reverse of os.link's.
"""
raise UnsupportedOperation(self._unsupported_msg('hardlink_to()'))
def touch(self, mode=0o666, exist_ok=True):
"""
Create this file with the given access mode, if it doesn't exist.
"""
raise UnsupportedOperation(self._unsupported_msg('touch()'))
def mkdir(self, mode=0o777, parents=False, exist_ok=False):
"""
Create a new directory at this given path.
"""
raise UnsupportedOperation(self._unsupported_msg('mkdir()'))
def copy(self, target, follow_symlinks=True):
"""
Copy the contents of this file to the given target. If this file is a
symlink and follow_symlinks is false, a symlink will be created at the
target.
"""
if not isinstance(target, PathBase):
target = self.with_segments(target)
if self._samefile_safe(target):
raise OSError(f"{self!r} and {target!r} are the same file")
if not follow_symlinks and self.is_symlink():
target.symlink_to(self.readlink())
return
with self.open('rb') as source_f:
try:
with target.open('wb') as target_f:
copyfileobj(source_f, target_f)
except IsADirectoryError as e:
if not target.exists():
# Raise a less confusing exception.
raise FileNotFoundError(
f'Directory does not exist: {target}') from e
else:
raise
def copytree(self, target, *, follow_symlinks=True, dirs_exist_ok=False,
ignore=None, on_error=None):
"""
Recursively copy this directory tree to the given destination.
"""
if not isinstance(target, PathBase):
target = self.with_segments(target)
if on_error is None:
def on_error(err):
raise err
stack = [(self, target)]
while stack:
source_dir, target_dir = stack.pop()
try:
sources = source_dir.iterdir()
target_dir.mkdir(exist_ok=dirs_exist_ok)
for source in sources:
if ignore and ignore(source):
continue
try:
if source.is_dir(follow_symlinks=follow_symlinks):
stack.append((source, target_dir.joinpath(source.name)))
else:
source.copy(target_dir.joinpath(source.name),
follow_symlinks=follow_symlinks)
except OSError as err:
on_error(err)
except OSError as err:
on_error(err)
def rename(self, target):
"""
Rename this path to the target path.
The target path may be absolute or relative. Relative paths are
interpreted relative to the current working directory, *not* the
directory of the Path object.
Returns the new Path instance pointing to the target path.
"""
raise UnsupportedOperation(self._unsupported_msg('rename()'))
def replace(self, target):
"""
Rename this path to the target path, overwriting if that path exists.
The target path may be absolute or relative. Relative paths are
interpreted relative to the current working directory, *not* the
directory of the Path object.
Returns the new Path instance pointing to the target path.
"""
raise UnsupportedOperation(self._unsupported_msg('replace()'))
def chmod(self, mode, *, follow_symlinks=True):
"""
Change the permissions of the path, like os.chmod().
"""
raise UnsupportedOperation(self._unsupported_msg('chmod()'))
def lchmod(self, mode):
"""
Like chmod(), except if the path points to a symlink, the symlink's
permissions are changed, rather than its target's.
"""
self.chmod(mode, follow_symlinks=False)
def unlink(self, missing_ok=False):
"""
Remove this file or link.
If the path is a directory, use rmdir() instead.
"""
raise UnsupportedOperation(self._unsupported_msg('unlink()'))
def rmdir(self):
"""
Remove this directory. The directory must be empty.
"""
raise UnsupportedOperation(self._unsupported_msg('rmdir()'))
def owner(self, *, follow_symlinks=True):
"""
Return the login name of the file owner.
"""
raise UnsupportedOperation(self._unsupported_msg('owner()'))
def group(self, *, follow_symlinks=True):
"""
Return the group name of the file gid.
"""
raise UnsupportedOperation(self._unsupported_msg('group()'))
@classmethod
def from_uri(cls, uri):
"""Return a new path from the given 'file' URI."""
raise UnsupportedOperation(cls._unsupported_msg('from_uri()'))
def as_uri(self):
"""Return the path as a URI."""
raise UnsupportedOperation(self._unsupported_msg('as_uri()'))