Expand shell variables of the forms $var, ${var} and %var%. Unknown variables are left unchanged.
(path)
| 378 | # XXX except '^|<>='. |
| 379 | |
| 380 | def expandvars(path): |
| 381 | """Expand shell variables of the forms $var, ${var} and %var%. |
| 382 | |
| 383 | Unknown variables are left unchanged.""" |
| 384 | path = os.fspath(path) |
| 385 | if isinstance(path, bytes): |
| 386 | if b'$' not in path and b'%' not in path: |
| 387 | return path |
| 388 | import string |
| 389 | varchars = bytes(string.ascii_letters + string.digits + '_-', 'ascii') |
| 390 | quote = b'\'' |
| 391 | percent = b'%' |
| 392 | brace = b'{' |
| 393 | rbrace = b'}' |
| 394 | dollar = b'$' |
| 395 | environ = getattr(os, 'environb', None) |
| 396 | else: |
| 397 | if '$' not in path and '%' not in path: |
| 398 | return path |
| 399 | import string |
| 400 | varchars = string.ascii_letters + string.digits + '_-' |
| 401 | quote = '\'' |
| 402 | percent = '%' |
| 403 | brace = '{' |
| 404 | rbrace = '}' |
| 405 | dollar = '$' |
| 406 | environ = os.environ |
| 407 | res = path[:0] |
| 408 | index = 0 |
| 409 | pathlen = len(path) |
| 410 | while index < pathlen: |
| 411 | c = path[index:index+1] |
| 412 | if c == quote: # no expansion within single quotes |
| 413 | path = path[index + 1:] |
| 414 | pathlen = len(path) |
| 415 | try: |
| 416 | index = path.index(c) |
| 417 | res += c + path[:index + 1] |
| 418 | except ValueError: |
| 419 | res += c + path |
| 420 | index = pathlen - 1 |
| 421 | elif c == percent: # variable or '%' |
| 422 | if path[index + 1:index + 2] == percent: |
| 423 | res += c |
| 424 | index += 1 |
| 425 | else: |
| 426 | path = path[index+1:] |
| 427 | pathlen = len(path) |
| 428 | try: |
| 429 | index = path.index(percent) |
| 430 | except ValueError: |
| 431 | res += percent + path |
| 432 | index = pathlen - 1 |
| 433 | else: |
| 434 | var = path[:index] |
| 435 | try: |
| 436 | if environ is None: |
| 437 | value = os.fsencode(os.environ[os.fsdecode(var)]) |