cpython/Lib/posixpath.py at e83ce850f433fd8bbf8ff4e8d7649b942639db31 · python/cpython · GitHub

Repository navigation

History

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

"""Common operations on Posix pathnames.

Instead of importing this module directly, import os and refer to

this module as os.path. The "os.path" name is an alias for this

module on Posix systems; on other systems (e.g. Windows),

os.path provides the same operations in a manner specific to that

platform, and is an alias to another module (e.g. ntpath).

Some of this can actually be useful on non-Posix systems too, e.g.

for manipulation of the pathname component of URLs.

"""

# Strings representing various path-related bits and pieces.

# These are primarily for export; internally, they are hardcoded.

# Should be set before imports for resolving cyclic dependency.

curdir = '.'

pardir = '..'

extsep = '.'

sep = '/'

pathsep = ':'

defpath = '/bin:/usr/bin'

altsep = None

devnull = '/dev/null'

import errno

import os

import sys

import stat

import genericpath

from genericpath import *

__all__ = ["normcase","isabs","join","splitdrive","splitroot","split","splitext",

"basename","dirname","commonprefix","getsize","getmtime",

"getatime","getctime","islink","exists","lexists","isdir","isfile",

"ismount", "expanduser","expandvars","normpath","abspath",

"samefile","sameopenfile","samestat",

"curdir","pardir","sep","pathsep","defpath","altsep","extsep",

"devnull","realpath","supports_unicode_filenames","relpath",

"commonpath", "isjunction","isdevdrive"]

def _get_sep(path):

if isinstance(path, bytes):

return b'/'

else:

return '/'

# Normalize the case of a pathname. Trivial in Posix, string.lower on Mac.

# On MS-DOS this may also turn slashes into backslashes; however, other

# normalizations (such as optimizing '../' away) are not allowed

# (another function should be defined to do that).

def normcase(s):

"""Normalize case of pathname. Has no effect under Posix"""

return os.fspath(s)

# Return whether a path is absolute.

# Trivial in Posix, harder on the Mac or MS-DOS.

def isabs(s):

"""Test whether a path is absolute"""

s = os.fspath(s)

sep = _get_sep(s)

return s.startswith(sep)

# Join pathnames.

# Ignore the previous parts if a part is absolute.

# Insert a '/' unless the first part is empty or already ends in '/'.

def join(a, *p):

"""Join two or more pathname components, inserting '/' as needed.

If any component is an absolute path, all previous path components

will be discarded. An empty last part will result in a path that

ends with a separator."""

a = os.fspath(a)

sep = _get_sep(a)

path = a

try:

for b in p:

b = os.fspath(b)

if b.startswith(sep) or not path:

path = b

elif path.endswith(sep):

path += b

else:

path += sep + b

except (TypeError, AttributeError, BytesWarning):

genericpath._check_arg_types('join', a, *p)

raise

return path

# Split a path in head (everything up to the last '/') and tail (the

# rest). If the path ends in '/', tail will be empty. If there is no

# '/' in the path, head will be empty.

# Trailing '/'es are stripped from head unless it is the root.

def split(p):

"""Split a pathname. Returns tuple "(head, tail)" where "tail" is

everything after the final slash. Either part may be empty."""

p = os.fspath(p)

sep = _get_sep(p)

i = p.rfind(sep) + 1

head, tail = p[:i], p[i:]

if head and head != sep*len(head):

head = head.rstrip(sep)

return head, tail

# Split a path in root and extension.

# The extension is everything starting at the last dot in the last

# pathname component; the root is everything before that.

# It is always true that root + ext == p.

def splitext(p):

p = os.fspath(p)

if isinstance(p, bytes):

sep = b'/'

extsep = b'.'

else:

sep = '/'

extsep = '.'

return genericpath._splitext(p, sep, None, extsep)

splitext.__doc__ = genericpath._splitext.__doc__

# Split a pathname into a drive specification and the rest of the

# path. Useful on DOS/Windows/NT; on Unix, the drive is always empty.

def splitdrive(p):

"""Split a pathname into drive and path. On Posix, drive is always

empty."""

p = os.fspath(p)

return p[:0], p

try:

from posix import _path_splitroot_ex as splitroot

except ImportError:

def splitroot(p):

"""Split a pathname into drive, root and tail.

The tail contains anything after the root."""

p = os.fspath(p)

if isinstance(p, bytes):

sep = b'/'

empty = b''

else:

sep = '/'

empty = ''

if p[:1] != sep:

# Relative path, e.g.: 'foo'

return empty, empty, p

elif p[1:2] != sep or p[2:3] == sep:

# Absolute path, e.g.: '/foo', '///foo', '////foo', etc.

return empty, sep, p[1:]

else:

# Precisely two leading slashes, e.g.: '//foo'. Implementation defined per POSIX, see

# https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13

return empty, p[:2], p[2:]

# Return the tail (basename) part of a path, same as split(path)[1].

def basename(p):

"""Returns the final component of a pathname"""

p = os.fspath(p)

sep = _get_sep(p)

i = p.rfind(sep) + 1

return p[i:]

# Return the head (dirname) part of a path, same as split(path)[0].

def dirname(p):

"""Returns the directory component of a pathname"""

p = os.fspath(p)

sep = _get_sep(p)

i = p.rfind(sep) + 1

head = p[:i]

if head and head != sep*len(head):

head = head.rstrip(sep)

return head

# Is a path a mount point?

# (Does this work for all UNIXes? Is it even guaranteed to work by Posix?)

def ismount(path):

"""Test whether a path is a mount point"""

try:

s1 = os.lstat(path)

except (OSError, ValueError):

# It doesn't exist -- so not a mount point. :-)

return False

else:

# A symlink can never be a mount point

if stat.S_ISLNK(s1.st_mode):

return False

path = os.fspath(path)

if isinstance(path, bytes):

parent = join(path, b'..')

else:

parent = join(path, '..')

try:

s2 = os.lstat(parent)

except OSError:

parent = realpath(parent)

try:

s2 = os.lstat(parent)

except OSError:

return False

# path/.. on a different device as path or the same i-node as path

return s1.st_dev != s2.st_dev or s1.st_ino == s2.st_ino

# Expand paths beginning with '~' or '~user'.

# '~' means $HOME; '~user' means that user's home directory.

# If the path doesn't begin with '~', or if the user or $HOME is unknown,

# the path is returned unchanged (leaving error reporting to whatever

# function is called with the expanded path as argument).

# See also module 'glob' for expansion of *, ? and [...] in pathnames.

# (A function should also be defined to do full *sh-style environment

# variable expansion.)

def expanduser(path):

"""Expand ~ and ~user constructions. If user or $HOME is unknown,

do nothing."""

path = os.fspath(path)

if isinstance(path, bytes):

tilde = b'~'

else:

tilde = '~'

if not path.startswith(tilde):

return path

sep = _get_sep(path)

i = path.find(sep, 1)

if i < 0:

i = len(path)

if i == 1:

if 'HOME' not in os.environ:

try:

import pwd

except ImportError:

# pwd module unavailable, return path unchanged

return path

try:

userhome = pwd.getpwuid(os.getuid()).pw_dir

except KeyError:

# bpo-10496: if the current user identifier doesn't exist in the

# password database, return the path unchanged

return path

else:

userhome = os.environ['HOME']

else:

try:

import pwd

except ImportError:

# pwd module unavailable, return path unchanged

return path

name = path[1:i]

if isinstance(name, bytes):

name = os.fsdecode(name)

try:

pwent = pwd.getpwnam(name)

except KeyError:

# bpo-10496: if the user name from the path doesn't exist in the

# password database, return the path unchanged

return path

userhome = pwent.pw_dir

# if no user home, return the path unchanged on VxWorks

if userhome is None and sys.platform == "vxworks":

return path

if isinstance(path, bytes):

userhome = os.fsencode(userhome)

userhome = userhome.rstrip(sep)

return (userhome + path[i:]) or sep

# Expand paths containing shell variable substitutions.

# This expands the forms $variable and ${variable} only.

# Non-existent variables are left unchanged.

_varprog = None

_varprogb = None

def expandvars(path):

"""Expand shell variables of form $var and ${var}. Unknown variables

are left unchanged."""

path = os.fspath(path)

global _varprog, _varprogb

if isinstance(path, bytes):

if b'$' not in path:

return path

if not _varprogb:

import re

_varprogb = re.compile(br'\$(\w+|\{[^}]*\})', re.ASCII)

search = _varprogb.search

start = b'{'

end = b'}'

environ = getattr(os, 'environb', None)

else:

if '$' not in path:

return path

if not _varprog:

import re

_varprog = re.compile(r'\$(\w+|\{[^}]*\})', re.ASCII)

search = _varprog.search

start = '{'

end = '}'

environ = os.environ

i = 0

while True:

m = search(path, i)

if not m:

break

i, j = m.span(0)

name = m.group(1)

if name.startswith(start) and name.endswith(end):

name = name[1:-1]

try:

if environ is None:

value = os.fsencode(os.environ[os.fsdecode(name)])

else:

value = environ[name]

except KeyError:

i = j

else:

tail = path[j:]

path = path[:i] + value

i = len(path)

path += tail

return path

# Normalize a path, e.g. A//B, A/./B and A/foo/../B all become A/B.

# It should be understood that this may change the meaning of the path

# if it contains symbolic links!

try:

from posix import _path_normpath as normpath

except ImportError:

def normpath(path):

"""Normalize path, eliminating double slashes, etc."""

path = os.fspath(path)

if isinstance(path, bytes):

sep = b'/'

dot = b'.'

dotdot = b'..'

else:

sep = '/'

dot = '.'

dotdot = '..'

if not path:

return dot

_, initial_slashes, path = splitroot(path)

comps = path.split(sep)

new_comps = []

for comp in comps:

if not comp or comp == dot:

continue

if (comp != dotdot or (not initial_slashes and not new_comps) or

(new_comps and new_comps[-1] == dotdot)):

new_comps.append(comp)

elif new_comps:

new_comps.pop()

comps = new_comps

path = initial_slashes + sep.join(comps)

return path or dot

def abspath(path):

"""Return an absolute path."""

path = os.fspath(path)

if isinstance(path, bytes):

if not path.startswith(b'/'):

path = join(os.getcwdb(), path)

else:

if not path.startswith('/'):

path = join(os.getcwd(), path)

return normpath(path)

# Return a canonical path (i.e. the absolute location of a file on the

# filesystem).

def realpath(filename, *, strict=False):

"""Return the canonical path of the specified filename, eliminating any

symbolic links encountered in the path."""

filename = os.fspath(filename)

if isinstance(filename, bytes):

sep = b'/'

curdir = b'.'

pardir = b'..'

getcwd = os.getcwdb

else:

sep = '/'

curdir = '.'

pardir = '..'

getcwd = os.getcwd

return _realpath(filename, strict, sep, curdir, pardir, getcwd)

def _realpath(filename, strict=False, sep=sep, curdir=curdir, pardir=pardir,

getcwd=os.getcwd, lstat=os.lstat, readlink=os.readlink, maxlinks=None):

# The stack of unresolved path parts. When popped, a special value of None

# indicates that a symlink target has been resolved, and that the original

# symlink path can be retrieved by popping again. The [::-1] slice is a

# very fast way of spelling list(reversed(...)).

rest = filename.split(sep)[::-1]

# The resolved path, which is absolute throughout this function.

# Note: getcwd() returns a normalized and symlink-free path.

path = sep if filename.startswith(sep) else getcwd()

# Mapping from symlink paths to *fully resolved* symlink targets. If a

# symlink is encountered but not yet resolved, the value is None. This is

# used both to detect symlink loops and to speed up repeated traversals of

# the same links.

seen = {}

# Number of symlinks traversed. When the number of traversals is limited

# by *maxlinks*, this is used instead of *seen* to detect symlink loops.

link_count = 0

while rest:

name = rest.pop()

if name is None:

# resolved symlink target

seen[rest.pop()] = path

continue

if not name or name == curdir:

# current dir

continue

if name == pardir:

# parent dir

path = path[:path.rindex(sep)] or sep

continue

if path == sep:

newpath = path + name

else:

newpath = path + sep + name

try:

st = lstat(newpath)

if not stat.S_ISLNK(st.st_mode):

path = newpath

continue

elif maxlinks is not None:

link_count += 1

if link_count > maxlinks:

if strict:

raise OSError(errno.ELOOP, os.strerror(errno.ELOOP),

newpath)

path = newpath

continue

elif newpath in seen:

# Already seen this path

path = seen[newpath]

if path is not None:

# use cached value

continue

# The symlink is not resolved, so we must have a symlink loop.

if strict:

raise OSError(errno.ELOOP, os.strerror(errno.ELOOP),

newpath)

path = newpath

continue

target = readlink(newpath)

except OSError:

if strict:

raise

path = newpath

continue

# Resolve the symbolic link

if target.startswith(sep):

# Symlink target is absolute; reset resolved path.

path = sep

if maxlinks is None:

# Mark this symlink as seen but not fully resolved.

seen[newpath] = None

# Push the symlink path onto the stack, and signal its specialness

# by also pushing None. When these entries are popped, we'll

# record the fully-resolved symlink target in the 'seen' mapping.

rest.append(newpath)

rest.append(None)

# Push the unresolved symlink target parts onto the stack.

rest.extend(target.split(sep)[::-1])

return path

supports_unicode_filenames = (sys.platform == 'darwin')

def relpath(path, start=None):

"""Return a relative version of a path"""

path = os.fspath(path)

if not path:

raise ValueError("no path specified")

if isinstance(path, bytes):

curdir = b'.'

sep = b'/'

pardir = b'..'

else:

curdir = '.'

sep = '/'

pardir = '..'

if start is None:

start = curdir

else:

start = os.fspath(start)

try:

start_tail = abspath(start).lstrip(sep)

path_tail = abspath(path).lstrip(sep)

start_list = start_tail.split(sep) if start_tail else []

path_list = path_tail.split(sep) if path_tail else []

# Work out how much of the filepath is shared by start and path.

i = len(commonprefix([start_list, path_list]))

rel_list = [pardir] * (len(start_list)-i) + path_list[i:]

if not rel_list:

return curdir

return sep.join(rel_list)

except (TypeError, AttributeError, BytesWarning, DeprecationWarning):

genericpath._check_arg_types('relpath', path, start)

raise

# Return the longest common sub-path of the sequence of paths given as input.

# The paths are not normalized before comparing them (this is the

# responsibility of the caller). Any trailing separator is stripped from the

# returned path.

def commonpath(paths):

"""Given a sequence of path names, returns the longest common sub-path."""

paths = tuple(map(os.fspath, paths))

if not paths:

raise ValueError('commonpath() arg is an empty sequence')

if isinstance(paths[0], bytes):

sep = b'/'

curdir = b'.'

else:

sep = '/'

curdir = '.'

try:

split_paths = [path.split(sep) for path in paths]

try:

isabs, = {p.startswith(sep) for p in paths}

except ValueError:

raise ValueError("Can't mix absolute and relative paths") from None

split_paths = [[c for c in s if c and c != curdir] for s in split_paths]

s1 = min(split_paths)

s2 = max(split_paths)

common = s1

for i, c in enumerate(s1):

if c != s2[i]:

common = s1[:i]

break

prefix = sep if isabs else sep[:0]

return prefix + sep.join(common)

except (TypeError, AttributeError):

genericpath._check_arg_types('commonpath', *paths)

raise

cpython/Lib/posixpath.py at e83ce850f433fd8bbf8ff4e8d7649b942639db31 · python/cpython · GitHub

Repository navigation

Expand file tree

Breadcrumbs

posixpath.py

Latest commit

History

Breadcrumbs

posixpath.py

File metadata and controls