1"""Core implementation of path-based import. 2 3This module is NOT meant to be directly imported! It has been designed such 4that it can be bootstrapped into Python as the implementation of import. As 5such it requires the injection of specific modules and attributes in order to 6work. One should use importlib as the public-facing version of this module. 7 8""" 9# IMPORTANT: Whenever making changes to this module, be sure to run a top-level 10# `make regen-importlib` followed by `make` in order to get the frozen version 11# of the module updated. Not doing so will result in the Makefile to fail for 12# all others who don't have a ./python around to freeze the module in the early 13# stages of compilation. 14# 15 16# See importlib._setup() for what is injected into the global namespace. 17 18# When editing this code be aware that code executed at import time CANNOT 19# reference any injected objects! This includes not only global code but also 20# anything specified at the class level. 21 22# Bootstrap-related code ###################################################### 23_CASE_INSENSITIVE_PLATFORMS_STR_KEY = 'win', 24_CASE_INSENSITIVE_PLATFORMS_BYTES_KEY = 'cygwin', 'darwin' 25_CASE_INSENSITIVE_PLATFORMS = (_CASE_INSENSITIVE_PLATFORMS_BYTES_KEY 26 + _CASE_INSENSITIVE_PLATFORMS_STR_KEY) 27 28 29def _make_relax_case(): 30 if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS): 31 if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS_STR_KEY): 32 key = 'PYTHONCASEOK' 33 else: 34 key = b'PYTHONCASEOK' 35 36 def _relax_case(): 37 """True if filenames must be checked case-insensitively.""" 38 return key in _os.environ 39 else: 40 def _relax_case(): 41 """True if filenames must be checked case-insensitively.""" 42 return False 43 return _relax_case 44 45 46def _pack_uint32(x): 47 """Convert a 32-bit integer to little-endian.""" 48 return (int(x) & 0xFFFFFFFF).to_bytes(4, 'little') 49 50 51def _unpack_uint32(data): 52 """Convert 4 bytes in little-endian to an integer.""" 53 assert len(data) == 4 54 return int.from_bytes(data, 'little') 55 56def _unpack_uint16(data): 57 """Convert 2 bytes in little-endian to an integer.""" 58 assert len(data) == 2 59 return int.from_bytes(data, 'little') 60 61 62def _path_join(*path_parts): 63 """Replacement for os.path.join().""" 64 return path_sep.join([part.rstrip(path_separators) 65 for part in path_parts if part]) 66 67 68def _path_split(path): 69 """Replacement for os.path.split().""" 70 if len(path_separators) == 1: 71 front, _, tail = path.rpartition(path_sep) 72 return front, tail 73 for x in reversed(path): 74 if x in path_separators: 75 front, tail = path.rsplit(x, maxsplit=1) 76 return front, tail 77 return '', path 78 79 80def _path_stat(path): 81 """Stat the path. 82 83 Made a separate function to make it easier to override in experiments 84 (e.g. cache stat results). 85 86 """ 87 return _os.stat(path) 88 89 90def _path_is_mode_type(path, mode): 91 """Test whether the path is the specified mode type.""" 92 try: 93 stat_info = _path_stat(path) 94 except OSError: 95 return False 96 return (stat_info.st_mode & 0o170000) == mode 97 98 99def _path_isfile(path): 100 """Replacement for os.path.isfile.""" 101 return _path_is_mode_type(path, 0o100000) 102 103 104def _path_isdir(path): 105 """Replacement for os.path.isdir.""" 106 if not path: 107 path = _os.getcwd() 108 return _path_is_mode_type(path, 0o040000) 109 110 111def _path_isabs(path): 112 """Replacement for os.path.isabs. 113 114 Considers a Windows drive-relative path (no drive, but starts with slash) to 115 still be "absolute". 116 """ 117 return path.startswith(path_separators) or path[1:3] in _pathseps_with_colon 118 119 120def _write_atomic(path, data, mode=0o666): 121 """Best-effort function to write data to a path atomically. 122 Be prepared to handle a FileExistsError if concurrent writing of the 123 temporary file is attempted.""" 124 # id() is used to generate a pseudo-random filename. 125 path_tmp = '{}.{}'.format(path, id(path)) 126 fd = _os.open(path_tmp, 127 _os.O_EXCL | _os.O_CREAT | _os.O_WRONLY, mode & 0o666) 128 try: 129 # We first write data to a temporary file, and then use os.replace() to 130 # perform an atomic rename. 131 with _io.FileIO(fd, 'wb') as file: 132 file.write(data) 133 _os.replace(path_tmp, path) 134 except OSError: 135 try: 136 _os.unlink(path_tmp) 137 except OSError: 138 pass 139 raise 140 141 142_code_type = type(_write_atomic.__code__) 143 144 145# Finder/loader utility code ############################################### 146 147# Magic word to reject .pyc files generated by other Python versions. 148# It should change for each incompatible change to the bytecode. 149# 150# The value of CR and LF is incorporated so if you ever read or write 151# a .pyc file in text mode the magic number will be wrong; also, the 152# Apple MPW compiler swaps their values, botching string constants. 153# 154# There were a variety of old schemes for setting the magic number. 155# The current working scheme is to increment the previous value by 156# 10. 157# 158# Starting with the adoption of PEP 3147 in Python 3.2, every bump in magic 159# number also includes a new "magic tag", i.e. a human readable string used 160# to represent the magic number in __pycache__ directories. When you change 161# the magic number, you must also set a new unique magic tag. Generally this 162# can be named after the Python major version of the magic number bump, but 163# it can really be anything, as long as it's different than anything else 164# that's come before. The tags are included in the following table, starting 165# with Python 3.2a0. 166# 167# Known values: 168# Python 1.5: 20121 169# Python 1.5.1: 20121 170# Python 1.5.2: 20121 171# Python 1.6: 50428 172# Python 2.0: 50823 173# Python 2.0.1: 50823 174# Python 2.1: 60202 175# Python 2.1.1: 60202 176# Python 2.1.2: 60202 177# Python 2.2: 60717 178# Python 2.3a0: 62011 179# Python 2.3a0: 62021 180# Python 2.3a0: 62011 (!) 181# Python 2.4a0: 62041 182# Python 2.4a3: 62051 183# Python 2.4b1: 62061 184# Python 2.5a0: 62071 185# Python 2.5a0: 62081 (ast-branch) 186# Python 2.5a0: 62091 (with) 187# Python 2.5a0: 62092 (changed WITH_CLEANUP opcode) 188# Python 2.5b3: 62101 (fix wrong code: for x, in ...) 189# Python 2.5b3: 62111 (fix wrong code: x += yield) 190# Python 2.5c1: 62121 (fix wrong lnotab with for loops and 191# storing constants that should have been removed) 192# Python 2.5c2: 62131 (fix wrong code: for x, in ... in listcomp/genexp) 193# Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode) 194# Python 2.6a1: 62161 (WITH_CLEANUP optimization) 195# Python 2.7a0: 62171 (optimize list comprehensions/change LIST_APPEND) 196# Python 2.7a0: 62181 (optimize conditional branches: 197# introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE) 198# Python 2.7a0 62191 (introduce SETUP_WITH) 199# Python 2.7a0 62201 (introduce BUILD_SET) 200# Python 2.7a0 62211 (introduce MAP_ADD and SET_ADD) 201# Python 3000: 3000 202# 3010 (removed UNARY_CONVERT) 203# 3020 (added BUILD_SET) 204# 3030 (added keyword-only parameters) 205# 3040 (added signature annotations) 206# 3050 (print becomes a function) 207# 3060 (PEP 3115 metaclass syntax) 208# 3061 (string literals become unicode) 209# 3071 (PEP 3109 raise changes) 210# 3081 (PEP 3137 make __file__ and __name__ unicode) 211# 3091 (kill str8 interning) 212# 3101 (merge from 2.6a0, see 62151) 213# 3103 (__file__ points to source file) 214# Python 3.0a4: 3111 (WITH_CLEANUP optimization). 215# Python 3.0b1: 3131 (lexical exception stacking, including POP_EXCEPT 216 #3021) 217# Python 3.1a1: 3141 (optimize list, set and dict comprehensions: 218# change LIST_APPEND and SET_ADD, add MAP_ADD #2183) 219# Python 3.1a1: 3151 (optimize conditional branches: 220# introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE 221 #4715) 222# Python 3.2a1: 3160 (add SETUP_WITH #6101) 223# tag: cpython-32 224# Python 3.2a2: 3170 (add DUP_TOP_TWO, remove DUP_TOPX and ROT_FOUR #9225) 225# tag: cpython-32 226# Python 3.2a3 3180 (add DELETE_DEREF #4617) 227# Python 3.3a1 3190 (__class__ super closure changed) 228# Python 3.3a1 3200 (PEP 3155 __qualname__ added #13448) 229# Python 3.3a1 3210 (added size modulo 2**32 to the pyc header #13645) 230# Python 3.3a2 3220 (changed PEP 380 implementation #14230) 231# Python 3.3a4 3230 (revert changes to implicit __class__ closure #14857) 232# Python 3.4a1 3250 (evaluate positional default arguments before 233# keyword-only defaults #16967) 234# Python 3.4a1 3260 (add LOAD_CLASSDEREF; allow locals of class to override 235# free vars #17853) 236# Python 3.4a1 3270 (various tweaks to the __class__ closure #12370) 237# Python 3.4a1 3280 (remove implicit class argument) 238# Python 3.4a4 3290 (changes to __qualname__ computation #19301) 239# Python 3.4a4 3300 (more changes to __qualname__ computation #19301) 240# Python 3.4rc2 3310 (alter __qualname__ computation #20625) 241# Python 3.5a1 3320 (PEP 465: Matrix multiplication operator #21176) 242# Python 3.5b1 3330 (PEP 448: Additional Unpacking Generalizations #2292) 243# Python 3.5b2 3340 (fix dictionary display evaluation order #11205) 244# Python 3.5b3 3350 (add GET_YIELD_FROM_ITER opcode #24400) 245# Python 3.5.2 3351 (fix BUILD_MAP_UNPACK_WITH_CALL opcode #27286) 246# Python 3.6a0 3360 (add FORMAT_VALUE opcode #25483) 247# Python 3.6a1 3361 (lineno delta of code.co_lnotab becomes signed #26107) 248# Python 3.6a2 3370 (16 bit wordcode #26647) 249# Python 3.6a2 3371 (add BUILD_CONST_KEY_MAP opcode #27140) 250# Python 3.6a2 3372 (MAKE_FUNCTION simplification, remove MAKE_CLOSURE 251# #27095) 252# Python 3.6b1 3373 (add BUILD_STRING opcode #27078) 253# Python 3.6b1 3375 (add SETUP_ANNOTATIONS and STORE_ANNOTATION opcodes 254# #27985) 255# Python 3.6b1 3376 (simplify CALL_FUNCTIONs & BUILD_MAP_UNPACK_WITH_CALL 256 #27213) 257# Python 3.6b1 3377 (set __class__ cell from type.__new__ #23722) 258# Python 3.6b2 3378 (add BUILD_TUPLE_UNPACK_WITH_CALL #28257) 259# Python 3.6rc1 3379 (more thorough __class__ validation #23722) 260# Python 3.7a1 3390 (add LOAD_METHOD and CALL_METHOD opcodes #26110) 261# Python 3.7a2 3391 (update GET_AITER #31709) 262# Python 3.7a4 3392 (PEP 552: Deterministic pycs #31650) 263# Python 3.7b1 3393 (remove STORE_ANNOTATION opcode #32550) 264# Python 3.7b5 3394 (restored docstring as the first stmt in the body; 265# this might affected the first line number #32911) 266# Python 3.8a1 3400 (move frame block handling to compiler #17611) 267# Python 3.8a1 3401 (add END_ASYNC_FOR #33041) 268# Python 3.8a1 3410 (PEP570 Python Positional-Only Parameters #36540) 269# Python 3.8b2 3411 (Reverse evaluation order of key: value in dict 270# comprehensions #35224) 271# Python 3.8b2 3412 (Swap the position of positional args and positional 272# only args in ast.arguments #37593) 273# Python 3.8b4 3413 (Fix "break" and "continue" in "finally" #37830) 274# 275# MAGIC must change whenever the bytecode emitted by the compiler may no 276# longer be understood by older implementations of the eval loop (usually 277# due to the addition of new opcodes). 278# 279# Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array 280# in PC/launcher.c must also be updated. 281 282MAGIC_NUMBER = (3413).to_bytes(2, 'little') + b'\r\n' 283_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c 284 285_PYCACHE = '__pycache__' 286_OPT = 'opt-' 287 288SOURCE_SUFFIXES = ['.py'] # _setup() adds .pyw as needed. 289 290BYTECODE_SUFFIXES = ['.pyc'] 291# Deprecated. 292DEBUG_BYTECODE_SUFFIXES = OPTIMIZED_BYTECODE_SUFFIXES = BYTECODE_SUFFIXES 293 294def cache_from_source(path, debug_override=None, *, optimization=None): 295 """Given the path to a .py file, return the path to its .pyc file. 296 297 The .py file does not need to exist; this simply returns the path to the 298 .pyc file calculated as if the .py file were imported. 299 300 The 'optimization' parameter controls the presumed optimization level of 301 the bytecode file. If 'optimization' is not None, the string representation 302 of the argument is taken and verified to be alphanumeric (else ValueError 303 is raised). 304 305 The debug_override parameter is deprecated. If debug_override is not None, 306 a True value is the same as setting 'optimization' to the empty string 307 while a False value is equivalent to setting 'optimization' to '1'. 308 309 If sys.implementation.cache_tag is None then NotImplementedError is raised. 310 311 """ 312 if debug_override is not None: 313 _warnings.warn('the debug_override parameter is deprecated; use ' 314 "'optimization' instead", DeprecationWarning) 315 if optimization is not None: 316 message = 'debug_override or optimization must be set to None' 317 raise TypeError(message) 318 optimization = '' if debug_override else 1 319 path = _os.fspath(path) 320 head, tail = _path_split(path) 321 base, sep, rest = tail.rpartition('.') 322 tag = sys.implementation.cache_tag 323 if tag is None: 324 raise NotImplementedError('sys.implementation.cache_tag is None') 325 almost_filename = ''.join([(base if base else rest), sep, tag]) 326 if optimization is None: 327 if sys.flags.optimize == 0: 328 optimization = '' 329 else: 330 optimization = sys.flags.optimize 331 optimization = str(optimization) 332 if optimization != '': 333 if not optimization.isalnum(): 334 raise ValueError('{!r} is not alphanumeric'.format(optimization)) 335 almost_filename = '{}.{}{}'.format(almost_filename, _OPT, optimization) 336 filename = almost_filename + BYTECODE_SUFFIXES[0] 337 if sys.pycache_prefix is not None: 338 # We need an absolute path to the py file to avoid the possibility of 339 # collisions within sys.pycache_prefix, if someone has two different 340 # `foo/bar.py` on their system and they import both of them using the 341 # same sys.pycache_prefix. Let's say sys.pycache_prefix is 342 # `C:\Bytecode`; the idea here is that if we get `Foo\Bar`, we first 343 # make it absolute (`C:\Somewhere\Foo\Bar`), then make it root-relative 344 # (`Somewhere\Foo\Bar`), so we end up placing the bytecode file in an 345 # unambiguous `C:\Bytecode\Somewhere\Foo\Bar\`. 346 if not _path_isabs(head): 347 head = _path_join(_os.getcwd(), head) 348 349 # Strip initial drive from a Windows path. We know we have an absolute 350 # path here, so the second part of the check rules out a POSIX path that 351 # happens to contain a colon at the second character. 352 if head[1] == ':' and head[0] not in path_separators: 353 head = head[2:] 354 355 # Strip initial path separator from `head` to complete the conversion 356 # back to a root-relative path before joining. 357 return _path_join( 358 sys.pycache_prefix, 359 head.lstrip(path_separators), 360 filename, 361 ) 362 return _path_join(head, _PYCACHE, filename) 363 364 365def source_from_cache(path): 366 """Given the path to a .pyc. file, return the path to its .py file. 367 368 The .pyc file does not need to exist; this simply returns the path to 369 the .py file calculated to correspond to the .pyc file. If path does 370 not conform to PEP 3147/488 format, ValueError will be raised. If 371 sys.implementation.cache_tag is None then NotImplementedError is raised. 372 373 """ 374 if sys.implementation.cache_tag is None: 375 raise NotImplementedError('sys.implementation.cache_tag is None') 376 path = _os.fspath(path) 377 head, pycache_filename = _path_split(path) 378 found_in_pycache_prefix = False 379 if sys.pycache_prefix is not None: 380 stripped_path = sys.pycache_prefix.rstrip(path_separators) 381 if head.startswith(stripped_path + path_sep): 382 head = head[len(stripped_path):] 383 found_in_pycache_prefix = True 384 if not found_in_pycache_prefix: 385 head, pycache = _path_split(head) 386 if pycache != _PYCACHE: 387 raise ValueError(f'{_PYCACHE} not bottom-level directory in ' 388 f'{path!r}') 389 dot_count = pycache_filename.count('.') 390 if dot_count not in {2, 3}: 391 raise ValueError(f'expected only 2 or 3 dots in {pycache_filename!r}') 392 elif dot_count == 3: 393 optimization = pycache_filename.rsplit('.', 2)[-2] 394 if not optimization.startswith(_OPT): 395 raise ValueError("optimization portion of filename does not start " 396 f"with {_OPT!r}") 397 opt_level = optimization[len(_OPT):] 398 if not opt_level.isalnum(): 399 raise ValueError(f"optimization level {optimization!r} is not an " 400 "alphanumeric value") 401 base_filename = pycache_filename.partition('.')[0] 402 return _path_join(head, base_filename + SOURCE_SUFFIXES[0]) 403 404 405def _get_sourcefile(bytecode_path): 406 """Convert a bytecode file path to a source path (if possible). 407 408 This function exists purely for backwards-compatibility for 409 PyImport_ExecCodeModuleWithFilenames() in the C API. 410 411 """ 412 if len(bytecode_path) == 0: 413 return None 414 rest, _, extension = bytecode_path.rpartition('.') 415 if not rest or extension.lower()[-3:-1] != 'py': 416 return bytecode_path 417 try: 418 source_path = source_from_cache(bytecode_path) 419 except (NotImplementedError, ValueError): 420 source_path = bytecode_path[:-1] 421 return source_path if _path_isfile(source_path) else bytecode_path 422 423 424def _get_cached(filename): 425 if filename.endswith(tuple(SOURCE_SUFFIXES)): 426 try: 427 return cache_from_source(filename) 428 except NotImplementedError: 429 pass 430 elif filename.endswith(tuple(BYTECODE_SUFFIXES)): 431 return filename 432 else: 433 return None 434 435 436def _calc_mode(path): 437 """Calculate the mode permissions for a bytecode file.""" 438 try: 439 mode = _path_stat(path).st_mode 440 except OSError: 441 mode = 0o666 442 # We always ensure write access so we can update cached files 443 # later even when the source files are read-only on Windows (#6074) 444 mode |= 0o200 445 return mode 446 447 448def _check_name(method): 449 """Decorator to verify that the module being requested matches the one the 450 loader can handle. 451 452 The first argument (self) must define _name which the second argument is 453 compared against. If the comparison fails then ImportError is raised. 454 455 """ 456 def _check_name_wrapper(self, name=None, *args, **kwargs): 457 if name is None: 458 name = self.name 459 elif self.name != name: 460 raise ImportError('loader for %s cannot handle %s' % 461 (self.name, name), name=name) 462 return method(self, name, *args, **kwargs) 463 try: 464 _wrap = _bootstrap._wrap 465 except NameError: 466 # XXX yuck 467 def _wrap(new, old): 468 for replace in ['__module__', '__name__', '__qualname__', '__doc__']: 469 if hasattr(old, replace): 470 setattr(new, replace, getattr(old, replace)) 471 new.__dict__.update(old.__dict__) 472 _wrap(_check_name_wrapper, method) 473 return _check_name_wrapper 474 475 476def _find_module_shim(self, fullname): 477 """Try to find a loader for the specified module by delegating to 478 self.find_loader(). 479 480 This method is deprecated in favor of finder.find_spec(). 481 482 """ 483 # Call find_loader(). If it returns a string (indicating this 484 # is a namespace package portion), generate a warning and 485 # return None. 486 loader, portions = self.find_loader(fullname) 487 if loader is None and len(portions): 488 msg = 'Not importing directory {}: missing __init__' 489 _warnings.warn(msg.format(portions[0]), ImportWarning) 490 return loader 491 492 493def _classify_pyc(data, name, exc_details): 494 """Perform basic validity checking of a pyc header and return the flags field, 495 which determines how the pyc should be further validated against the source. 496 497 *data* is the contents of the pyc file. (Only the first 16 bytes are 498 required, though.) 499 500 *name* is the name of the module being imported. It is used for logging. 501 502 *exc_details* is a dictionary passed to ImportError if it raised for 503 improved debugging. 504 505 ImportError is raised when the magic number is incorrect or when the flags 506 field is invalid. EOFError is raised when the data is found to be truncated. 507 508 """ 509 magic = data[:4] 510 if magic != MAGIC_NUMBER: 511 message = f'bad magic number in {name!r}: {magic!r}' 512 _bootstrap._verbose_message('{}', message) 513 raise ImportError(message, **exc_details) 514 if len(data) < 16: 515 message = f'reached EOF while reading pyc header of {name!r}' 516 _bootstrap._verbose_message('{}', message) 517 raise EOFError(message) 518 flags = _unpack_uint32(data[4:8]) 519 # Only the first two flags are defined. 520 if flags & ~0b11: 521 message = f'invalid flags {flags!r} in {name!r}' 522 raise ImportError(message, **exc_details) 523 return flags 524 525 526def _validate_timestamp_pyc(data, source_mtime, source_size, name, 527 exc_details): 528 """Validate a pyc against the source last-modified time. 529 530 *data* is the contents of the pyc file. (Only the first 16 bytes are 531 required.) 532 533 *source_mtime* is the last modified timestamp of the source file. 534 535 *source_size* is None or the size of the source file in bytes. 536 537 *name* is the name of the module being imported. It is used for logging. 538 539 *exc_details* is a dictionary passed to ImportError if it raised for 540 improved debugging. 541 542 An ImportError is raised if the bytecode is stale. 543 544 """ 545 if _unpack_uint32(data[8:12]) != (source_mtime & 0xFFFFFFFF): 546 message = f'bytecode is stale for {name!r}' 547 _bootstrap._verbose_message('{}', message) 548 raise ImportError(message, **exc_details) 549 if (source_size is not None and 550 _unpack_uint32(data[12:16]) != (source_size & 0xFFFFFFFF)): 551 raise ImportError(f'bytecode is stale for {name!r}', **exc_details) 552 553 554def _validate_hash_pyc(data, source_hash, name, exc_details): 555 """Validate a hash-based pyc by checking the real source hash against the one in 556 the pyc header. 557 558 *data* is the contents of the pyc file. (Only the first 16 bytes are 559 required.) 560 561 *source_hash* is the importlib.util.source_hash() of the source file. 562 563 *name* is the name of the module being imported. It is used for logging. 564 565 *exc_details* is a dictionary passed to ImportError if it raised for 566 improved debugging. 567 568 An ImportError is raised if the bytecode is stale. 569 570 """ 571 if data[8:16] != source_hash: 572 raise ImportError( 573 f'hash in bytecode doesn\'t match hash of source {name!r}', 574 **exc_details, 575 ) 576 577 578def _compile_bytecode(data, name=None, bytecode_path=None, source_path=None): 579 """Compile bytecode as found in a pyc.""" 580 code = marshal.loads(data) 581 if isinstance(code, _code_type): 582 _bootstrap._verbose_message('code object from {!r}', bytecode_path) 583 if source_path is not None: 584 _imp._fix_co_filename(code, source_path) 585 return code 586 else: 587 raise ImportError('Non-code object in {!r}'.format(bytecode_path), 588 name=name, path=bytecode_path) 589 590 591def _code_to_timestamp_pyc(code, mtime=0, source_size=0): 592 "Produce the data for a timestamp-based pyc." 593 data = bytearray(MAGIC_NUMBER) 594 data.extend(_pack_uint32(0)) 595 data.extend(_pack_uint32(mtime)) 596 data.extend(_pack_uint32(source_size)) 597 data.extend(marshal.dumps(code)) 598 return data 599 600 601def _code_to_hash_pyc(code, source_hash, checked=True): 602 "Produce the data for a hash-based pyc." 603 data = bytearray(MAGIC_NUMBER) 604 flags = 0b1 | checked << 1 605 data.extend(_pack_uint32(flags)) 606 assert len(source_hash) == 8 607 data.extend(source_hash) 608 data.extend(marshal.dumps(code)) 609 return data 610 611 612def decode_source(source_bytes): 613 """Decode bytes representing source code and return the string. 614 615 Universal newline support is used in the decoding. 616 """ 617 import tokenize # To avoid bootstrap issues. 618 source_bytes_readline = _io.BytesIO(source_bytes).readline 619 encoding = tokenize.detect_encoding(source_bytes_readline) 620 newline_decoder = _io.IncrementalNewlineDecoder(None, True) 621 return newline_decoder.decode(source_bytes.decode(encoding[0])) 622 623 624# Module specifications ####################################################### 625 626_POPULATE = object() 627 628 629def spec_from_file_location(name, location=None, *, loader=None, 630 submodule_search_locations=_POPULATE): 631 """Return a module spec based on a file location. 632 633 To indicate that the module is a package, set 634 submodule_search_locations to a list of directory paths. An 635 empty list is sufficient, though its not otherwise useful to the 636 import system. 637 638 The loader must take a spec as its only __init__() arg. 639 640 """ 641 if location is None: 642 # The caller may simply want a partially populated location- 643 # oriented spec. So we set the location to a bogus value and 644 # fill in as much as we can. 645 location = '<unknown>' 646 if hasattr(loader, 'get_filename'): 647 # ExecutionLoader 648 try: 649 location = loader.get_filename(name) 650 except ImportError: 651 pass 652 else: 653 location = _os.fspath(location) 654 655 # If the location is on the filesystem, but doesn't actually exist, 656 # we could return None here, indicating that the location is not 657 # valid. However, we don't have a good way of testing since an 658 # indirect location (e.g. a zip file or URL) will look like a 659 # non-existent file relative to the filesystem. 660 661 spec = _bootstrap.ModuleSpec(name, loader, origin=location) 662 spec._set_fileattr = True 663 664 # Pick a loader if one wasn't provided. 665 if loader is None: 666 for loader_class, suffixes in _get_supported_file_loaders(): 667 if location.endswith(tuple(suffixes)): 668 loader = loader_class(name, location) 669 spec.loader = loader 670 break 671 else: 672 return None 673 674 # Set submodule_search_paths appropriately. 675 if submodule_search_locations is _POPULATE: 676 # Check the loader. 677 if hasattr(loader, 'is_package'): 678 try: 679 is_package = loader.is_package(name) 680 except ImportError: 681 pass 682 else: 683 if is_package: 684 spec.submodule_search_locations = [] 685 else: 686 spec.submodule_search_locations = submodule_search_locations 687 if spec.submodule_search_locations == []: 688 if location: 689 dirname = _path_split(location)[0] 690 spec.submodule_search_locations.append(dirname) 691 692 return spec 693 694 695# Loaders ##################################################################### 696 697class WindowsRegistryFinder: 698 699 """Meta path finder for modules declared in the Windows registry.""" 700 701 REGISTRY_KEY = ( 702 'Software\\Python\\PythonCore\\{sys_version}' 703 '\\Modules\\{fullname}') 704 REGISTRY_KEY_DEBUG = ( 705 'Software\\Python\\PythonCore\\{sys_version}' 706 '\\Modules\\{fullname}\\Debug') 707 DEBUG_BUILD = False # Changed in _setup() 708 709 @classmethod 710 def _open_registry(cls, key): 711 try: 712 return _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, key) 713 except OSError: 714 return _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE, key) 715 716 @classmethod 717 def _search_registry(cls, fullname): 718 if cls.DEBUG_BUILD: 719 registry_key = cls.REGISTRY_KEY_DEBUG 720 else: 721 registry_key = cls.REGISTRY_KEY 722 key = registry_key.format(fullname=fullname, 723 sys_version='%d.%d' % sys.version_info[:2]) 724 try: 725 with cls._open_registry(key) as hkey: 726 filepath = _winreg.QueryValue(hkey, '') 727 except OSError: 728 return None 729 return filepath 730 731 @classmethod 732 def find_spec(cls, fullname, path=None, target=None): 733 filepath = cls._search_registry(fullname) 734 if filepath is None: 735 return None 736 try: 737 _path_stat(filepath) 738 except OSError: 739 return None 740 for loader, suffixes in _get_supported_file_loaders(): 741 if filepath.endswith(tuple(suffixes)): 742 spec = _bootstrap.spec_from_loader(fullname, 743 loader(fullname, filepath), 744 origin=filepath) 745 return spec 746 747 @classmethod 748 def find_module(cls, fullname, path=None): 749 """Find module named in the registry. 750 751 This method is deprecated. Use exec_module() instead. 752 753 """ 754 spec = cls.find_spec(fullname, path) 755 if spec is not None: 756 return spec.loader 757 else: 758 return None 759 760 761class _LoaderBasics: 762 763 """Base class of common code needed by both SourceLoader and 764 SourcelessFileLoader.""" 765 766 def is_package(self, fullname): 767 """Concrete implementation of InspectLoader.is_package by checking if 768 the path returned by get_filename has a filename of '__init__.py'.""" 769 filename = _path_split(self.get_filename(fullname))[1] 770 filename_base = filename.rsplit('.', 1)[0] 771 tail_name = fullname.rpartition('.')[2] 772 return filename_base == '__init__' and tail_name != '__init__' 773 774 def create_module(self, spec): 775 """Use default semantics for module creation.""" 776 777 def exec_module(self, module): 778 """Execute the module.""" 779 code = self.get_code(module.__name__) 780 if code is None: 781 raise ImportError('cannot load module {!r} when get_code() ' 782 'returns None'.format(module.__name__)) 783 _bootstrap._call_with_frames_removed(exec, code, module.__dict__) 784 785 def load_module(self, fullname): 786 """This module is deprecated.""" 787 return _bootstrap._load_module_shim(self, fullname) 788 789 790class SourceLoader(_LoaderBasics): 791 792 def path_mtime(self, path): 793 """Optional method that returns the modification time (an int) for the 794 specified path (a str). 795 796 Raises OSError when the path cannot be handled. 797 """ 798 raise OSError 799 800 def path_stats(self, path): 801 """Optional method returning a metadata dict for the specified 802 path (a str). 803 804 Possible keys: 805 - 'mtime' (mandatory) is the numeric timestamp of last source 806 code modification; 807 - 'size' (optional) is the size in bytes of the source code. 808 809 Implementing this method allows the loader to read bytecode files. 810 Raises OSError when the path cannot be handled. 811 """ 812 return {'mtime': self.path_mtime(path)} 813 814 def _cache_bytecode(self, source_path, cache_path, data): 815 """Optional method which writes data (bytes) to a file path (a str). 816 817 Implementing this method allows for the writing of bytecode files. 818 819 The source path is needed in order to correctly transfer permissions 820 """ 821 # For backwards compatibility, we delegate to set_data() 822 return self.set_data(cache_path, data) 823 824 def set_data(self, path, data): 825 """Optional method which writes data (bytes) to a file path (a str). 826 827 Implementing this method allows for the writing of bytecode files. 828 """ 829 830 831 def get_source(self, fullname): 832 """Concrete implementation of InspectLoader.get_source.""" 833 path = self.get_filename(fullname) 834 try: 835 source_bytes = self.get_data(path) 836 except OSError as exc: 837 raise ImportError('source not available through get_data()', 838 name=fullname) from exc 839 return decode_source(source_bytes) 840 841 def source_to_code(self, data, path, *, _optimize=-1): 842 """Return the code object compiled from source. 843 844 The 'data' argument can be any object type that compile() supports. 845 """ 846 return _bootstrap._call_with_frames_removed(compile, data, path, 'exec', 847 dont_inherit=True, optimize=_optimize) 848 849 def get_code(self, fullname): 850 """Concrete implementation of InspectLoader.get_code. 851 852 Reading of bytecode requires path_stats to be implemented. To write 853 bytecode, set_data must also be implemented. 854 855 """ 856 source_path = self.get_filename(fullname) 857 source_mtime = None 858 source_bytes = None 859 source_hash = None 860 hash_based = False 861 check_source = True 862 try: 863 bytecode_path = cache_from_source(source_path) 864 except NotImplementedError: 865 bytecode_path = None 866 else: 867 try: 868 st = self.path_stats(source_path) 869 except OSError: 870 pass 871 else: 872 source_mtime = int(st['mtime']) 873 try: 874 data = self.get_data(bytecode_path) 875 except OSError: 876 pass 877 else: 878 exc_details = { 879 'name': fullname, 880 'path': bytecode_path, 881 } 882 try: 883 flags = _classify_pyc(data, fullname, exc_details) 884 bytes_data = memoryview(data)[16:] 885 hash_based = flags & 0b1 != 0 886 if hash_based: 887 check_source = flags & 0b10 != 0 888 if (_imp.check_hash_based_pycs != 'never' and 889 (check_source or 890 _imp.check_hash_based_pycs == 'always')): 891 source_bytes = self.get_data(source_path) 892 source_hash = _imp.source_hash( 893 _RAW_MAGIC_NUMBER, 894 source_bytes, 895 ) 896 _validate_hash_pyc(data, source_hash, fullname, 897 exc_details) 898 else: 899 _validate_timestamp_pyc( 900 data, 901 source_mtime, 902 st['size'], 903 fullname, 904 exc_details, 905 ) 906 except (ImportError, EOFError): 907 pass 908 else: 909 _bootstrap._verbose_message('{} matches {}', bytecode_path, 910 source_path) 911 return _compile_bytecode(bytes_data, name=fullname, 912 bytecode_path=bytecode_path, 913 source_path=source_path) 914 if source_bytes is None: 915 source_bytes = self.get_data(source_path) 916 code_object = self.source_to_code(source_bytes, source_path) 917 _bootstrap._verbose_message('code object from {}', source_path) 918 if (not sys.dont_write_bytecode and bytecode_path is not None and 919 source_mtime is not None): 920 if hash_based: 921 if source_hash is None: 922 source_hash = _imp.source_hash(source_bytes) 923 data = _code_to_hash_pyc(code_object, source_hash, check_source) 924 else: 925 data = _code_to_timestamp_pyc(code_object, source_mtime, 926 len(source_bytes)) 927 try: 928 self._cache_bytecode(source_path, bytecode_path, data) 929 except NotImplementedError: 930 pass 931 return code_object 932 933 934class FileLoader: 935 936 """Base file loader class which implements the loader protocol methods that 937 require file system usage.""" 938 939 def __init__(self, fullname, path): 940 """Cache the module name and the path to the file found by the 941 finder.""" 942 self.name = fullname 943 self.path = path 944 945 def __eq__(self, other): 946 return (self.__class__ == other.__class__ and 947 self.__dict__ == other.__dict__) 948 949 def __hash__(self): 950 return hash(self.name) ^ hash(self.path) 951 952 @_check_name 953 def load_module(self, fullname): 954 """Load a module from a file. 955 956 This method is deprecated. Use exec_module() instead. 957 958 """ 959 # The only reason for this method is for the name check. 960 # Issue #14857: Avoid the zero-argument form of super so the implementation 961 # of that form can be updated without breaking the frozen module 962 return super(FileLoader, self).load_module(fullname) 963 964 @_check_name 965 def get_filename(self, fullname): 966 """Return the path to the source file as found by the finder.""" 967 return self.path 968 969 def get_data(self, path): 970 """Return the data from path as raw bytes.""" 971 if isinstance(self, (SourceLoader, ExtensionFileLoader)): 972 with _io.open_code(str(path)) as file: 973 return file.read() 974 else: 975 with _io.FileIO(path, 'r') as file: 976 return file.read() 977 978 # ResourceReader ABC API. 979 980 @_check_name 981 def get_resource_reader(self, module): 982 if self.is_package(module): 983 return self 984 return None 985 986 def open_resource(self, resource): 987 path = _path_join(_path_split(self.path)[0], resource) 988 return _io.FileIO(path, 'r') 989 990 def resource_path(self, resource): 991 if not self.is_resource(resource): 992 raise FileNotFoundError 993 path = _path_join(_path_split(self.path)[0], resource) 994 return path 995 996 def is_resource(self, name): 997 if path_sep in name: 998 return False 999 path = _path_join(_path_split(self.path)[0], name) 1000 return _path_isfile(path) 1001 1002 def contents(self): 1003 return iter(_os.listdir(_path_split(self.path)[0])) 1004 1005 1006class SourceFileLoader(FileLoader, SourceLoader): 1007 1008 """Concrete implementation of SourceLoader using the file system.""" 1009 1010 def path_stats(self, path): 1011 """Return the metadata for the path.""" 1012 st = _path_stat(path) 1013 return {'mtime': st.st_mtime, 'size': st.st_size} 1014 1015 def _cache_bytecode(self, source_path, bytecode_path, data): 1016 # Adapt between the two APIs 1017 mode = _calc_mode(source_path) 1018 return self.set_data(bytecode_path, data, _mode=mode) 1019 1020 def set_data(self, path, data, *, _mode=0o666): 1021 """Write bytes data to a file.""" 1022 parent, filename = _path_split(path) 1023 path_parts = [] 1024 # Figure out what directories are missing. 1025 while parent and not _path_isdir(parent): 1026 parent, part = _path_split(parent) 1027 path_parts.append(part) 1028 # Create needed directories. 1029 for part in reversed(path_parts): 1030 parent = _path_join(parent, part) 1031 try: 1032 _os.mkdir(parent) 1033 except FileExistsError: 1034 # Probably another Python process already created the dir. 1035 continue 1036 except OSError as exc: 1037 # Could be a permission error, read-only filesystem: just forget 1038 # about writing the data. 1039 _bootstrap._verbose_message('could not create {!r}: {!r}', 1040 parent, exc) 1041 return 1042 try: 1043 _write_atomic(path, data, _mode) 1044 _bootstrap._verbose_message('created {!r}', path) 1045 except OSError as exc: 1046 # Same as above: just don't write the bytecode. 1047 _bootstrap._verbose_message('could not create {!r}: {!r}', path, 1048 exc) 1049 1050 1051class SourcelessFileLoader(FileLoader, _LoaderBasics): 1052 1053 """Loader which handles sourceless file imports.""" 1054 1055 def get_code(self, fullname): 1056 path = self.get_filename(fullname) 1057 data = self.get_data(path) 1058 # Call _classify_pyc to do basic validation of the pyc but ignore the 1059 # result. There's no source to check against. 1060 exc_details = { 1061 'name': fullname, 1062 'path': path, 1063 } 1064 _classify_pyc(data, fullname, exc_details) 1065 return _compile_bytecode( 1066 memoryview(data)[16:], 1067 name=fullname, 1068 bytecode_path=path, 1069 ) 1070 1071 def get_source(self, fullname): 1072 """Return None as there is no source code.""" 1073 return None 1074 1075 1076# Filled in by _setup(). 1077EXTENSION_SUFFIXES = [] 1078 1079 1080class ExtensionFileLoader(FileLoader, _LoaderBasics): 1081 1082 """Loader for extension modules. 1083 1084 The constructor is designed to work with FileFinder. 1085 1086 """ 1087 1088 def __init__(self, name, path): 1089 self.name = name 1090 self.path = path 1091 1092 def __eq__(self, other): 1093 return (self.__class__ == other.__class__ and 1094 self.__dict__ == other.__dict__) 1095 1096 def __hash__(self): 1097 return hash(self.name) ^ hash(self.path) 1098 1099 def create_module(self, spec): 1100 """Create an unitialized extension module""" 1101 module = _bootstrap._call_with_frames_removed( 1102 _imp.create_dynamic, spec) 1103 _bootstrap._verbose_message('extension module {!r} loaded from {!r}', 1104 spec.name, self.path) 1105 return module 1106 1107 def exec_module(self, module): 1108 """Initialize an extension module""" 1109 _bootstrap._call_with_frames_removed(_imp.exec_dynamic, module) 1110 _bootstrap._verbose_message('extension module {!r} executed from {!r}', 1111 self.name, self.path) 1112 1113 def is_package(self, fullname): 1114 """Return True if the extension module is a package.""" 1115 file_name = _path_split(self.path)[1] 1116 return any(file_name == '__init__' + suffix 1117 for suffix in EXTENSION_SUFFIXES) 1118 1119 def get_code(self, fullname): 1120 """Return None as an extension module cannot create a code object.""" 1121 return None 1122 1123 def get_source(self, fullname): 1124 """Return None as extension modules have no source code.""" 1125 return None 1126 1127 @_check_name 1128 def get_filename(self, fullname): 1129 """Return the path to the source file as found by the finder.""" 1130 return self.path 1131 1132 1133class _NamespacePath: 1134 """Represents a namespace package's path. It uses the module name 1135 to find its parent module, and from there it looks up the parent's 1136 __path__. When this changes, the module's own path is recomputed, 1137 using path_finder. For top-level modules, the parent module's path 1138 is sys.path.""" 1139 1140 def __init__(self, name, path, path_finder): 1141 self._name = name 1142 self._path = path 1143 self._last_parent_path = tuple(self._get_parent_path()) 1144 self._path_finder = path_finder 1145 1146 def _find_parent_path_names(self): 1147 """Returns a tuple of (parent-module-name, parent-path-attr-name)""" 1148 parent, dot, me = self._name.rpartition('.') 1149 if dot == '': 1150 # This is a top-level module. sys.path contains the parent path. 1151 return 'sys', 'path' 1152 # Not a top-level module. parent-module.__path__ contains the 1153 # parent path. 1154 return parent, '__path__' 1155 1156 def _get_parent_path(self): 1157 parent_module_name, path_attr_name = self._find_parent_path_names() 1158 return getattr(sys.modules[parent_module_name], path_attr_name) 1159 1160 def _recalculate(self): 1161 # If the parent's path has changed, recalculate _path 1162 parent_path = tuple(self._get_parent_path()) # Make a copy 1163 if parent_path != self._last_parent_path: 1164 spec = self._path_finder(self._name, parent_path) 1165 # Note that no changes are made if a loader is returned, but we 1166 # do remember the new parent path 1167 if spec is not None and spec.loader is None: 1168 if spec.submodule_search_locations: 1169 self._path = spec.submodule_search_locations 1170 self._last_parent_path = parent_path # Save the copy 1171 return self._path 1172 1173 def __iter__(self): 1174 return iter(self._recalculate()) 1175 1176 def __getitem__(self, index): 1177 return self._recalculate()[index] 1178 1179 def __setitem__(self, index, path): 1180 self._path[index] = path 1181 1182 def __len__(self): 1183 return len(self._recalculate()) 1184 1185 def __repr__(self): 1186 return '_NamespacePath({!r})'.format(self._path) 1187 1188 def __contains__(self, item): 1189 return item in self._recalculate() 1190 1191 def append(self, item): 1192 self._path.append(item) 1193 1194 1195# We use this exclusively in module_from_spec() for backward-compatibility. 1196class _NamespaceLoader: 1197 def __init__(self, name, path, path_finder): 1198 self._path = _NamespacePath(name, path, path_finder) 1199 1200 @classmethod 1201 def module_repr(cls, module): 1202 """Return repr for the module. 1203 1204 The method is deprecated. The import machinery does the job itself. 1205 1206 """ 1207 return '<module {!r} (namespace)>'.format(module.__name__) 1208 1209 def is_package(self, fullname): 1210 return True 1211 1212 def get_source(self, fullname): 1213 return '' 1214 1215 def get_code(self, fullname): 1216 return compile('', '<string>', 'exec', dont_inherit=True) 1217 1218 def create_module(self, spec): 1219 """Use default semantics for module creation.""" 1220 1221 def exec_module(self, module): 1222 pass 1223 1224 def load_module(self, fullname): 1225 """Load a namespace module. 1226 1227 This method is deprecated. Use exec_module() instead. 1228 1229 """ 1230 # The import system never calls this method. 1231 _bootstrap._verbose_message('namespace module loaded with path {!r}', 1232 self._path) 1233 return _bootstrap._load_module_shim(self, fullname) 1234 1235 1236# Finders ##################################################################### 1237 1238class PathFinder: 1239 1240 """Meta path finder for sys.path and package __path__ attributes.""" 1241 1242 @classmethod 1243 def invalidate_caches(cls): 1244 """Call the invalidate_caches() method on all path entry finders 1245 stored in sys.path_importer_caches (where implemented).""" 1246 for name, finder in list(sys.path_importer_cache.items()): 1247 if finder is None: 1248 del sys.path_importer_cache[name] 1249 elif hasattr(finder, 'invalidate_caches'): 1250 finder.invalidate_caches() 1251 1252 @classmethod 1253 def _path_hooks(cls, path): 1254 """Search sys.path_hooks for a finder for 'path'.""" 1255 if sys.path_hooks is not None and not sys.path_hooks: 1256 _warnings.warn('sys.path_hooks is empty', ImportWarning) 1257 for hook in sys.path_hooks: 1258 try: 1259 return hook(path) 1260 except ImportError: 1261 continue 1262 else: 1263 return None 1264 1265 @classmethod 1266 def _path_importer_cache(cls, path): 1267 """Get the finder for the path entry from sys.path_importer_cache. 1268 1269 If the path entry is not in the cache, find the appropriate finder 1270 and cache it. If no finder is available, store None. 1271 1272 """ 1273 if path == '': 1274 try: 1275 path = _os.getcwd() 1276 except FileNotFoundError: 1277 # Don't cache the failure as the cwd can easily change to 1278 # a valid directory later on. 1279 return None 1280 try: 1281 finder = sys.path_importer_cache[path] 1282 except KeyError: 1283 finder = cls._path_hooks(path) 1284 sys.path_importer_cache[path] = finder 1285 return finder 1286 1287 @classmethod 1288 def _legacy_get_spec(cls, fullname, finder): 1289 # This would be a good place for a DeprecationWarning if 1290 # we ended up going that route. 1291 if hasattr(finder, 'find_loader'): 1292 loader, portions = finder.find_loader(fullname) 1293 else: 1294 loader = finder.find_module(fullname) 1295 portions = [] 1296 if loader is not None: 1297 return _bootstrap.spec_from_loader(fullname, loader) 1298 spec = _bootstrap.ModuleSpec(fullname, None) 1299 spec.submodule_search_locations = portions 1300 return spec 1301 1302 @classmethod 1303 def _get_spec(cls, fullname, path, target=None): 1304 """Find the loader or namespace_path for this module/package name.""" 1305 # If this ends up being a namespace package, namespace_path is 1306 # the list of paths that will become its __path__ 1307 namespace_path = [] 1308 for entry in path: 1309 if not isinstance(entry, (str, bytes)): 1310 continue 1311 finder = cls._path_importer_cache(entry) 1312 if finder is not None: 1313 if hasattr(finder, 'find_spec'): 1314 spec = finder.find_spec(fullname, target) 1315 else: 1316 spec = cls._legacy_get_spec(fullname, finder) 1317 if spec is None: 1318 continue 1319 if spec.loader is not None: 1320 return spec 1321 portions = spec.submodule_search_locations 1322 if portions is None: 1323 raise ImportError('spec missing loader') 1324 # This is possibly part of a namespace package. 1325 # Remember these path entries (if any) for when we 1326 # create a namespace package, and continue iterating 1327 # on path. 1328 namespace_path.extend(portions) 1329 else: 1330 spec = _bootstrap.ModuleSpec(fullname, None) 1331 spec.submodule_search_locations = namespace_path 1332 return spec 1333 1334 @classmethod 1335 def find_spec(cls, fullname, path=None, target=None): 1336 """Try to find a spec for 'fullname' on sys.path or 'path'. 1337 1338 The search is based on sys.path_hooks and sys.path_importer_cache. 1339 """ 1340 if path is None: 1341 path = sys.path 1342 spec = cls._get_spec(fullname, path, target) 1343 if spec is None: 1344 return None 1345 elif spec.loader is None: 1346 namespace_path = spec.submodule_search_locations 1347 if namespace_path: 1348 # We found at least one namespace path. Return a spec which 1349 # can create the namespace package. 1350 spec.origin = None 1351 spec.submodule_search_locations = _NamespacePath(fullname, namespace_path, cls._get_spec) 1352 return spec 1353 else: 1354 return None 1355 else: 1356 return spec 1357 1358 @classmethod 1359 def find_module(cls, fullname, path=None): 1360 """find the module on sys.path or 'path' based on sys.path_hooks and 1361 sys.path_importer_cache. 1362 1363 This method is deprecated. Use find_spec() instead. 1364 1365 """ 1366 spec = cls.find_spec(fullname, path) 1367 if spec is None: 1368 return None 1369 return spec.loader 1370 1371 @classmethod 1372 def find_distributions(cls, *args, **kwargs): 1373 """ 1374 Find distributions. 1375 1376 Return an iterable of all Distribution instances capable of 1377 loading the metadata for packages matching ``context.name`` 1378 (or all names if ``None`` indicated) along the paths in the list 1379 of directories ``context.path``. 1380 """ 1381 from importlib.metadata import MetadataPathFinder 1382 return MetadataPathFinder.find_distributions(*args, **kwargs) 1383 1384 1385class FileFinder: 1386 1387 """File-based finder. 1388 1389 Interactions with the file system are cached for performance, being 1390 refreshed when the directory the finder is handling has been modified. 1391 1392 """ 1393 1394 def __init__(self, path, *loader_details): 1395 """Initialize with the path to search on and a variable number of 1396 2-tuples containing the loader and the file suffixes the loader 1397 recognizes.""" 1398 loaders = [] 1399 for loader, suffixes in loader_details: 1400 loaders.extend((suffix, loader) for suffix in suffixes) 1401 self._loaders = loaders 1402 # Base (directory) path 1403 self.path = path or '.' 1404 self._path_mtime = -1 1405 self._path_cache = set() 1406 self._relaxed_path_cache = set() 1407 1408 def invalidate_caches(self): 1409 """Invalidate the directory mtime.""" 1410 self._path_mtime = -1 1411 1412 find_module = _find_module_shim 1413 1414 def find_loader(self, fullname): 1415 """Try to find a loader for the specified module, or the namespace 1416 package portions. Returns (loader, list-of-portions). 1417 1418 This method is deprecated. Use find_spec() instead. 1419 1420 """ 1421 spec = self.find_spec(fullname) 1422 if spec is None: 1423 return None, [] 1424 return spec.loader, spec.submodule_search_locations or [] 1425 1426 def _get_spec(self, loader_class, fullname, path, smsl, target): 1427 loader = loader_class(fullname, path) 1428 return spec_from_file_location(fullname, path, loader=loader, 1429 submodule_search_locations=smsl) 1430 1431 def find_spec(self, fullname, target=None): 1432 """Try to find a spec for the specified module. 1433 1434 Returns the matching spec, or None if not found. 1435 """ 1436 is_namespace = False 1437 tail_module = fullname.rpartition('.')[2] 1438 try: 1439 mtime = _path_stat(self.path or _os.getcwd()).st_mtime 1440 except OSError: 1441 mtime = -1 1442 if mtime != self._path_mtime: 1443 self._fill_cache() 1444 self._path_mtime = mtime 1445 # tail_module keeps the original casing, for __file__ and friends 1446 if _relax_case(): 1447 cache = self._relaxed_path_cache 1448 cache_module = tail_module.lower() 1449 else: 1450 cache = self._path_cache 1451 cache_module = tail_module 1452 # Check if the module is the name of a directory (and thus a package). 1453 if cache_module in cache: 1454 base_path = _path_join(self.path, tail_module) 1455 for suffix, loader_class in self._loaders: 1456 init_filename = '__init__' + suffix 1457 full_path = _path_join(base_path, init_filename) 1458 if _path_isfile(full_path): 1459 return self._get_spec(loader_class, fullname, full_path, [base_path], target) 1460 else: 1461 # If a namespace package, return the path if we don't 1462 # find a module in the next section. 1463 is_namespace = _path_isdir(base_path) 1464 # Check for a file w/ a proper suffix exists. 1465 for suffix, loader_class in self._loaders: 1466 full_path = _path_join(self.path, tail_module + suffix) 1467 _bootstrap._verbose_message('trying {}', full_path, verbosity=2) 1468 if cache_module + suffix in cache: 1469 if _path_isfile(full_path): 1470 return self._get_spec(loader_class, fullname, full_path, 1471 None, target) 1472 if is_namespace: 1473 _bootstrap._verbose_message('possible namespace for {}', base_path) 1474 spec = _bootstrap.ModuleSpec(fullname, None) 1475 spec.submodule_search_locations = [base_path] 1476 return spec 1477 return None 1478 1479 def _fill_cache(self): 1480 """Fill the cache of potential modules and packages for this directory.""" 1481 path = self.path 1482 try: 1483 contents = _os.listdir(path or _os.getcwd()) 1484 except (FileNotFoundError, PermissionError, NotADirectoryError): 1485 # Directory has either been removed, turned into a file, or made 1486 # unreadable. 1487 contents = [] 1488 # We store two cached versions, to handle runtime changes of the 1489 # PYTHONCASEOK environment variable. 1490 if not sys.platform.startswith('win'): 1491 self._path_cache = set(contents) 1492 else: 1493 # Windows users can import modules with case-insensitive file 1494 # suffixes (for legacy reasons). Make the suffix lowercase here 1495 # so it's done once instead of for every import. This is safe as 1496 # the specified suffixes to check against are always specified in a 1497 # case-sensitive manner. 1498 lower_suffix_contents = set() 1499 for item in contents: 1500 name, dot, suffix = item.partition('.') 1501 if dot: 1502 new_name = '{}.{}'.format(name, suffix.lower()) 1503 else: 1504 new_name = name 1505 lower_suffix_contents.add(new_name) 1506 self._path_cache = lower_suffix_contents 1507 if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS): 1508 self._relaxed_path_cache = {fn.lower() for fn in contents} 1509 1510 @classmethod 1511 def path_hook(cls, *loader_details): 1512 """A class method which returns a closure to use on sys.path_hook 1513 which will return an instance using the specified loaders and the path 1514 called on the closure. 1515 1516 If the path called on the closure is not a directory, ImportError is 1517 raised. 1518 1519 """ 1520 def path_hook_for_FileFinder(path): 1521 """Path hook for importlib.machinery.FileFinder.""" 1522 if not _path_isdir(path): 1523 raise ImportError('only directories are supported', path=path) 1524 return cls(path, *loader_details) 1525 1526 return path_hook_for_FileFinder 1527 1528 def __repr__(self): 1529 return 'FileFinder({!r})'.format(self.path) 1530 1531 1532# Import setup ############################################################### 1533 1534def _fix_up_module(ns, name, pathname, cpathname=None): 1535 # This function is used by PyImport_ExecCodeModuleObject(). 1536 loader = ns.get('__loader__') 1537 spec = ns.get('__spec__') 1538 if not loader: 1539 if spec: 1540 loader = spec.loader 1541 elif pathname == cpathname: 1542 loader = SourcelessFileLoader(name, pathname) 1543 else: 1544 loader = SourceFileLoader(name, pathname) 1545 if not spec: 1546 spec = spec_from_file_location(name, pathname, loader=loader) 1547 try: 1548 ns['__spec__'] = spec 1549 ns['__loader__'] = loader 1550 ns['__file__'] = pathname 1551 ns['__cached__'] = cpathname 1552 except Exception: 1553 # Not important enough to report. 1554 pass 1555 1556 1557def _get_supported_file_loaders(): 1558 """Returns a list of file-based module loaders. 1559 1560 Each item is a tuple (loader, suffixes). 1561 """ 1562 extensions = ExtensionFileLoader, _imp.extension_suffixes() 1563 source = SourceFileLoader, SOURCE_SUFFIXES 1564 bytecode = SourcelessFileLoader, BYTECODE_SUFFIXES 1565 return [extensions, source, bytecode] 1566 1567 1568def _setup(_bootstrap_module): 1569 """Setup the path-based importers for importlib by importing needed 1570 built-in modules and injecting them into the global namespace. 1571 1572 Other components are extracted from the core bootstrap module. 1573 1574 """ 1575 global sys, _imp, _bootstrap 1576 _bootstrap = _bootstrap_module 1577 sys = _bootstrap.sys 1578 _imp = _bootstrap._imp 1579 1580 # Directly load built-in modules needed during bootstrap. 1581 self_module = sys.modules[__name__] 1582 for builtin_name in ('_io', '_warnings', 'builtins', 'marshal'): 1583 if builtin_name not in sys.modules: 1584 builtin_module = _bootstrap._builtin_from_name(builtin_name) 1585 else: 1586 builtin_module = sys.modules[builtin_name] 1587 setattr(self_module, builtin_name, builtin_module) 1588 1589 # Directly load the os module (needed during bootstrap). 1590 os_details = ('posix', ['/']), ('nt', ['\\', '/']) 1591 for builtin_os, path_separators in os_details: 1592 # Assumption made in _path_join() 1593 assert all(len(sep) == 1 for sep in path_separators) 1594 path_sep = path_separators[0] 1595 if builtin_os in sys.modules: 1596 os_module = sys.modules[builtin_os] 1597 break 1598 else: 1599 try: 1600 os_module = _bootstrap._builtin_from_name(builtin_os) 1601 break 1602 except ImportError: 1603 continue 1604 else: 1605 raise ImportError('importlib requires posix or nt') 1606 setattr(self_module, '_os', os_module) 1607 setattr(self_module, 'path_sep', path_sep) 1608 setattr(self_module, 'path_separators', ''.join(path_separators)) 1609 setattr(self_module, '_pathseps_with_colon', {f':{s}' for s in path_separators}) 1610 1611 # Directly load the _thread module (needed during bootstrap). 1612 thread_module = _bootstrap._builtin_from_name('_thread') 1613 setattr(self_module, '_thread', thread_module) 1614 1615 # Directly load the _weakref module (needed during bootstrap). 1616 weakref_module = _bootstrap._builtin_from_name('_weakref') 1617 setattr(self_module, '_weakref', weakref_module) 1618 1619 # Directly load the winreg module (needed during bootstrap). 1620 if builtin_os == 'nt': 1621 winreg_module = _bootstrap._builtin_from_name('winreg') 1622 setattr(self_module, '_winreg', winreg_module) 1623 1624 # Constants 1625 setattr(self_module, '_relax_case', _make_relax_case()) 1626 EXTENSION_SUFFIXES.extend(_imp.extension_suffixes()) 1627 if builtin_os == 'nt': 1628 SOURCE_SUFFIXES.append('.pyw') 1629 if '_d.pyd' in EXTENSION_SUFFIXES: 1630 WindowsRegistryFinder.DEBUG_BUILD = True 1631 1632 1633def _install(_bootstrap_module): 1634 """Install the path-based import components.""" 1635 _setup(_bootstrap_module) 1636 supported_loaders = _get_supported_file_loaders() 1637 sys.path_hooks.extend([FileFinder.path_hook(*supported_loaders)]) 1638 sys.meta_path.append(PathFinder) 1639