diff options
Diffstat (limited to 'Lib/importlib/_bootstrap_external.py')
| -rw-r--r-- | Lib/importlib/_bootstrap_external.py | 1426 |
1 files changed, 1426 insertions, 0 deletions
diff --git a/Lib/importlib/_bootstrap_external.py b/Lib/importlib/_bootstrap_external.py new file mode 100644 index 0000000000..3508ce96b0 --- /dev/null +++ b/Lib/importlib/_bootstrap_external.py @@ -0,0 +1,1426 @@ +"""Core implementation of path-based import. + +This module is NOT meant to be directly imported! It has been designed such +that it can be bootstrapped into Python as the implementation of import. As +such it requires the injection of specific modules and attributes in order to +work. One should use importlib as the public-facing version of this module. + +""" +# +# IMPORTANT: Whenever making changes to this module, be sure to run +# a top-level make in order to get the frozen version of the module +# updated. Not doing so will result in the Makefile to fail for +# all others who don't have a ./python around to freeze the module +# in the early stages of compilation. +# + +# See importlib._setup() for what is injected into the global namespace. + +# When editing this code be aware that code executed at import time CANNOT +# reference any injected objects! This includes not only global code but also +# anything specified at the class level. + +# Bootstrap-related code ###################################################### + +_CASE_INSENSITIVE_PLATFORMS = 'win', 'cygwin', 'darwin' + + +def _make_relax_case(): + if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS): + def _relax_case(): + """True if filenames must be checked case-insensitively.""" + return b'PYTHONCASEOK' in _os.environ + else: + def _relax_case(): + """True if filenames must be checked case-insensitively.""" + return False + return _relax_case + + +def _w_long(x): + """Convert a 32-bit integer to little-endian.""" + return (int(x) & 0xFFFFFFFF).to_bytes(4, 'little') + + +def _r_long(int_bytes): + """Convert 4 bytes in little-endian to an integer.""" + return int.from_bytes(int_bytes, 'little') + + +def _path_join(*path_parts): + """Replacement for os.path.join().""" + return path_sep.join([part.rstrip(path_separators) + for part in path_parts if part]) + + +def _path_split(path): + """Replacement for os.path.split().""" + if len(path_separators) == 1: + front, _, tail = path.rpartition(path_sep) + return front, tail + for x in reversed(path): + if x in path_separators: + front, tail = path.rsplit(x, maxsplit=1) + return front, tail + return '', path + + +def _path_stat(path): + """Stat the path. + + Made a separate function to make it easier to override in experiments + (e.g. cache stat results). + + """ + return _os.stat(path) + + +def _path_is_mode_type(path, mode): + """Test whether the path is the specified mode type.""" + try: + stat_info = _path_stat(path) + except OSError: + return False + return (stat_info.st_mode & 0o170000) == mode + + +def _path_isfile(path): + """Replacement for os.path.isfile.""" + return _path_is_mode_type(path, 0o100000) + + +def _path_isdir(path): + """Replacement for os.path.isdir.""" + if not path: + path = _os.getcwd() + return _path_is_mode_type(path, 0o040000) + + +def _write_atomic(path, data, mode=0o666): + """Best-effort function to write data to a path atomically. + Be prepared to handle a FileExistsError if concurrent writing of the + temporary file is attempted.""" + # id() is used to generate a pseudo-random filename. + path_tmp = '{}.{}'.format(path, id(path)) + fd = _os.open(path_tmp, + _os.O_EXCL | _os.O_CREAT | _os.O_WRONLY, mode & 0o666) + try: + # We first write data to a temporary file, and then use os.replace() to + # perform an atomic rename. + with _io.FileIO(fd, 'wb') as file: + file.write(data) + _os.replace(path_tmp, path) + except OSError: + try: + _os.unlink(path_tmp) + except OSError: + pass + raise + + +_code_type = type(_write_atomic.__code__) + + +# Finder/loader utility code ############################################### + +# Magic word to reject .pyc files generated by other Python versions. +# It should change for each incompatible change to the bytecode. +# +# The value of CR and LF is incorporated so if you ever read or write +# a .pyc file in text mode the magic number will be wrong; also, the +# Apple MPW compiler swaps their values, botching string constants. +# +# The magic numbers must be spaced apart at least 2 values, as the +# -U interpeter flag will cause MAGIC+1 being used. They have been +# odd numbers for some time now. +# +# There were a variety of old schemes for setting the magic number. +# The current working scheme is to increment the previous value by +# 10. +# +# Starting with the adoption of PEP 3147 in Python 3.2, every bump in magic +# number also includes a new "magic tag", i.e. a human readable string used +# to represent the magic number in __pycache__ directories. When you change +# the magic number, you must also set a new unique magic tag. Generally this +# can be named after the Python major version of the magic number bump, but +# it can really be anything, as long as it's different than anything else +# that's come before. The tags are included in the following table, starting +# with Python 3.2a0. +# +# Known values: +# Python 1.5: 20121 +# Python 1.5.1: 20121 +# Python 1.5.2: 20121 +# Python 1.6: 50428 +# Python 2.0: 50823 +# Python 2.0.1: 50823 +# Python 2.1: 60202 +# Python 2.1.1: 60202 +# Python 2.1.2: 60202 +# Python 2.2: 60717 +# Python 2.3a0: 62011 +# Python 2.3a0: 62021 +# Python 2.3a0: 62011 (!) +# Python 2.4a0: 62041 +# Python 2.4a3: 62051 +# Python 2.4b1: 62061 +# Python 2.5a0: 62071 +# Python 2.5a0: 62081 (ast-branch) +# Python 2.5a0: 62091 (with) +# Python 2.5a0: 62092 (changed WITH_CLEANUP opcode) +# Python 2.5b3: 62101 (fix wrong code: for x, in ...) +# Python 2.5b3: 62111 (fix wrong code: x += yield) +# Python 2.5c1: 62121 (fix wrong lnotab with for loops and +# storing constants that should have been removed) +# Python 2.5c2: 62131 (fix wrong code: for x, in ... in listcomp/genexp) +# Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode) +# Python 2.6a1: 62161 (WITH_CLEANUP optimization) +# Python 2.7a0: 62171 (optimize list comprehensions/change LIST_APPEND) +# Python 2.7a0: 62181 (optimize conditional branches: +# introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE) +# Python 2.7a0 62191 (introduce SETUP_WITH) +# Python 2.7a0 62201 (introduce BUILD_SET) +# Python 2.7a0 62211 (introduce MAP_ADD and SET_ADD) +# Python 3000: 3000 +# 3010 (removed UNARY_CONVERT) +# 3020 (added BUILD_SET) +# 3030 (added keyword-only parameters) +# 3040 (added signature annotations) +# 3050 (print becomes a function) +# 3060 (PEP 3115 metaclass syntax) +# 3061 (string literals become unicode) +# 3071 (PEP 3109 raise changes) +# 3081 (PEP 3137 make __file__ and __name__ unicode) +# 3091 (kill str8 interning) +# 3101 (merge from 2.6a0, see 62151) +# 3103 (__file__ points to source file) +# Python 3.0a4: 3111 (WITH_CLEANUP optimization). +# Python 3.0a5: 3131 (lexical exception stacking, including POP_EXCEPT) +# Python 3.1a0: 3141 (optimize list, set and dict comprehensions: +# change LIST_APPEND and SET_ADD, add MAP_ADD) +# Python 3.1a0: 3151 (optimize conditional branches: +# introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE) +# Python 3.2a0: 3160 (add SETUP_WITH) +# tag: cpython-32 +# Python 3.2a1: 3170 (add DUP_TOP_TWO, remove DUP_TOPX and ROT_FOUR) +# tag: cpython-32 +# Python 3.2a2 3180 (add DELETE_DEREF) +# Python 3.3a0 3190 __class__ super closure changed +# Python 3.3a0 3200 (__qualname__ added) +# 3210 (added size modulo 2**32 to the pyc header) +# Python 3.3a1 3220 (changed PEP 380 implementation) +# Python 3.3a4 3230 (revert changes to implicit __class__ closure) +# Python 3.4a1 3250 (evaluate positional default arguments before +# keyword-only defaults) +# Python 3.4a1 3260 (add LOAD_CLASSDEREF; allow locals of class to override +# free vars) +# Python 3.4a1 3270 (various tweaks to the __class__ closure) +# Python 3.4a1 3280 (remove implicit class argument) +# Python 3.4a4 3290 (changes to __qualname__ computation) +# Python 3.4a4 3300 (more changes to __qualname__ computation) +# Python 3.4rc2 3310 (alter __qualname__ computation) +# Python 3.5a0 3320 (matrix multiplication operator) +# Python 3.5b1 3330 (PEP 448: Additional Unpacking Generalizations) +# Python 3.5b2 3340 (fix dictionary display evaluation order #11205) +# Python 3.5b2 3350 (add GET_YIELD_FROM_ITER opcode #24400) +# +# MAGIC must change whenever the bytecode emitted by the compiler may no +# longer be understood by older implementations of the eval loop (usually +# due to the addition of new opcodes). + +MAGIC_NUMBER = (3350).to_bytes(2, 'little') + b'\r\n' +_RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little') # For import.c + +_PYCACHE = '__pycache__' +_OPT = 'opt-' + +SOURCE_SUFFIXES = ['.py'] # _setup() adds .pyw as needed. + +BYTECODE_SUFFIXES = ['.pyc'] +# Deprecated. +DEBUG_BYTECODE_SUFFIXES = OPTIMIZED_BYTECODE_SUFFIXES = BYTECODE_SUFFIXES + +def cache_from_source(path, debug_override=None, *, optimization=None): + """Given the path to a .py file, return the path to its .pyc file. + + The .py file does not need to exist; this simply returns the path to the + .pyc file calculated as if the .py file were imported. + + The 'optimization' parameter controls the presumed optimization level of + the bytecode file. If 'optimization' is not None, the string representation + of the argument is taken and verified to be alphanumeric (else ValueError + is raised). + + The debug_override parameter is deprecated. If debug_override is not None, + a True value is the same as setting 'optimization' to the empty string + while a False value is equivalent to setting 'optimization' to '1'. + + If sys.implementation.cache_tag is None then NotImplementedError is raised. + + """ + if debug_override is not None: + _warnings.warn('the debug_override parameter is deprecated; use ' + "'optimization' instead", DeprecationWarning) + if optimization is not None: + message = 'debug_override or optimization must be set to None' + raise TypeError(message) + optimization = '' if debug_override else 1 + head, tail = _path_split(path) + base, sep, rest = tail.rpartition('.') + tag = sys.implementation.cache_tag + if tag is None: + raise NotImplementedError('sys.implementation.cache_tag is None') + almost_filename = ''.join([(base if base else rest), sep, tag]) + if optimization is None: + if sys.flags.optimize == 0: + optimization = '' + else: + optimization = sys.flags.optimize + optimization = str(optimization) + if optimization != '': + if not optimization.isalnum(): + raise ValueError('{!r} is not alphanumeric'.format(optimization)) + almost_filename = '{}.{}{}'.format(almost_filename, _OPT, optimization) + return _path_join(head, _PYCACHE, almost_filename + BYTECODE_SUFFIXES[0]) + + +def source_from_cache(path): + """Given the path to a .pyc. file, return the path to its .py file. + + The .pyc file does not need to exist; this simply returns the path to + the .py file calculated to correspond to the .pyc file. If path does + not conform to PEP 3147/488 format, ValueError will be raised. If + sys.implementation.cache_tag is None then NotImplementedError is raised. + + """ + if sys.implementation.cache_tag is None: + raise NotImplementedError('sys.implementation.cache_tag is None') + head, pycache_filename = _path_split(path) + head, pycache = _path_split(head) + if pycache != _PYCACHE: + raise ValueError('{} not bottom-level directory in ' + '{!r}'.format(_PYCACHE, path)) + dot_count = pycache_filename.count('.') + if dot_count not in {2, 3}: + raise ValueError('expected only 2 or 3 dots in ' + '{!r}'.format(pycache_filename)) + elif dot_count == 3: + optimization = pycache_filename.rsplit('.', 2)[-2] + if not optimization.startswith(_OPT): + raise ValueError("optimization portion of filename does not start " + "with {!r}".format(_OPT)) + opt_level = optimization[len(_OPT):] + if not opt_level.isalnum(): + raise ValueError("optimization level {!r} is not an alphanumeric " + "value".format(optimization)) + base_filename = pycache_filename.partition('.')[0] + return _path_join(head, base_filename + SOURCE_SUFFIXES[0]) + + +def _get_sourcefile(bytecode_path): + """Convert a bytecode file path to a source path (if possible). + + This function exists purely for backwards-compatibility for + PyImport_ExecCodeModuleWithFilenames() in the C API. + + """ + if len(bytecode_path) == 0: + return None + rest, _, extension = bytecode_path.rpartition('.') + if not rest or extension.lower()[-3:-1] != 'py': + return bytecode_path + try: + source_path = source_from_cache(bytecode_path) + except (NotImplementedError, ValueError): + source_path = bytecode_path[:-1] + return source_path if _path_isfile(source_path) else bytecode_path + + +def _get_cached(filename): + if filename.endswith(tuple(SOURCE_SUFFIXES)): + try: + return cache_from_source(filename) + except NotImplementedError: + pass + elif filename.endswith(tuple(BYTECODE_SUFFIXES)): + return filename + else: + return None + + +def _calc_mode(path): + """Calculate the mode permissions for a bytecode file.""" + try: + mode = _path_stat(path).st_mode + except OSError: + mode = 0o666 + # We always ensure write access so we can update cached files + # later even when the source files are read-only on Windows (#6074) + mode |= 0o200 + return mode + + +def _verbose_message(message, *args, verbosity=1): + """Print the message to stderr if -v/PYTHONVERBOSE is turned on.""" + if sys.flags.verbose >= verbosity: + if not message.startswith(('#', 'import ')): + message = '# ' + message + print(message.format(*args), file=sys.stderr) + + +def _check_name(method): + """Decorator to verify that the module being requested matches the one the + loader can handle. + + The first argument (self) must define _name which the second argument is + compared against. If the comparison fails then ImportError is raised. + + """ + def _check_name_wrapper(self, name=None, *args, **kwargs): + if name is None: + name = self.name + elif self.name != name: + raise ImportError('loader for %s cannot handle %s' % + (self.name, name), name=name) + return method(self, name, *args, **kwargs) + try: + _wrap = _bootstrap._wrap + except NameError: + # XXX yuck + def _wrap(new, old): + for replace in ['__module__', '__name__', '__qualname__', '__doc__']: + if hasattr(old, replace): + setattr(new, replace, getattr(old, replace)) + new.__dict__.update(old.__dict__) + _wrap(_check_name_wrapper, method) + return _check_name_wrapper + + +def _find_module_shim(self, fullname): + """Try to find a loader for the specified module by delegating to + self.find_loader(). + + This method is deprecated in favor of finder.find_spec(). + + """ + # Call find_loader(). If it returns a string (indicating this + # is a namespace package portion), generate a warning and + # return None. + loader, portions = self.find_loader(fullname) + if loader is None and len(portions): + msg = 'Not importing directory {}: missing __init__' + _warnings.warn(msg.format(portions[0]), ImportWarning) + return loader + + +def _validate_bytecode_header(data, source_stats=None, name=None, path=None): + """Validate the header of the passed-in bytecode against source_stats (if + given) and returning the bytecode that can be compiled by compile(). + + All other arguments are used to enhance error reporting. + + ImportError is raised when the magic number is incorrect or the bytecode is + found to be stale. EOFError is raised when the data is found to be + truncated. + + """ + exc_details = {} + if name is not None: + exc_details['name'] = name + else: + # To prevent having to make all messages have a conditional name. + name = '<bytecode>' + if path is not None: + exc_details['path'] = path + magic = data[:4] + raw_timestamp = data[4:8] + raw_size = data[8:12] + if magic != MAGIC_NUMBER: + message = 'bad magic number in {!r}: {!r}'.format(name, magic) + _verbose_message(message) + raise ImportError(message, **exc_details) + elif len(raw_timestamp) != 4: + message = 'reached EOF while reading timestamp in {!r}'.format(name) + _verbose_message(message) + raise EOFError(message) + elif len(raw_size) != 4: + message = 'reached EOF while reading size of source in {!r}'.format(name) + _verbose_message(message) + raise EOFError(message) + if source_stats is not None: + try: + source_mtime = int(source_stats['mtime']) + except KeyError: + pass + else: + if _r_long(raw_timestamp) != source_mtime: + message = 'bytecode is stale for {!r}'.format(name) + _verbose_message(message) + raise ImportError(message, **exc_details) + try: + source_size = source_stats['size'] & 0xFFFFFFFF + except KeyError: + pass + else: + if _r_long(raw_size) != source_size: + raise ImportError('bytecode is stale for {!r}'.format(name), + **exc_details) + return data[12:] + + +def _compile_bytecode(data, name=None, bytecode_path=None, source_path=None): + """Compile bytecode as returned by _validate_bytecode_header().""" + code = marshal.loads(data) + if isinstance(code, _code_type): + _verbose_message('code object from {!r}', bytecode_path) + if source_path is not None: + _imp._fix_co_filename(code, source_path) + return code + else: + raise ImportError('Non-code object in {!r}'.format(bytecode_path), + name=name, path=bytecode_path) + +def _code_to_bytecode(code, mtime=0, source_size=0): + """Compile a code object into bytecode for writing out to a byte-compiled + file.""" + data = bytearray(MAGIC_NUMBER) + data.extend(_w_long(mtime)) + data.extend(_w_long(source_size)) + data.extend(marshal.dumps(code)) + return data + + +def decode_source(source_bytes): + """Decode bytes representing source code and return the string. + + Universal newline support is used in the decoding. + """ + import tokenize # To avoid bootstrap issues. + source_bytes_readline = _io.BytesIO(source_bytes).readline + encoding = tokenize.detect_encoding(source_bytes_readline) + newline_decoder = _io.IncrementalNewlineDecoder(None, True) + return newline_decoder.decode(source_bytes.decode(encoding[0])) + + +# Module specifications ####################################################### + +_POPULATE = object() + + +def spec_from_file_location(name, location=None, *, loader=None, + submodule_search_locations=_POPULATE): + """Return a module spec based on a file location. + + To indicate that the module is a package, set + submodule_search_locations to a list of directory paths. An + empty list is sufficient, though its not otherwise useful to the + import system. + + The loader must take a spec as its only __init__() arg. + + """ + if location is None: + # The caller may simply want a partially populated location- + # oriented spec. So we set the location to a bogus value and + # fill in as much as we can. + location = '<unknown>' + if hasattr(loader, 'get_filename'): + # ExecutionLoader + try: + location = loader.get_filename(name) + except ImportError: + pass + + # If the location is on the filesystem, but doesn't actually exist, + # we could return None here, indicating that the location is not + # valid. However, we don't have a good way of testing since an + # indirect location (e.g. a zip file or URL) will look like a + # non-existent file relative to the filesystem. + + spec = _bootstrap.ModuleSpec(name, loader, origin=location) + spec._set_fileattr = True + + # Pick a loader if one wasn't provided. + if loader is None: + for loader_class, suffixes in _get_supported_file_loaders(): + if location.endswith(tuple(suffixes)): + loader = loader_class(name, location) + spec.loader = loader + break + else: + return None + + # Set submodule_search_paths appropriately. + if submodule_search_locations is _POPULATE: + # Check the loader. + if hasattr(loader, 'is_package'): + try: + is_package = loader.is_package(name) + except ImportError: + pass + else: + if is_package: + spec.submodule_search_locations = [] + else: + spec.submodule_search_locations = submodule_search_locations + if spec.submodule_search_locations == []: + if location: + dirname = _path_split(location)[0] + spec.submodule_search_locations.append(dirname) + + return spec + + +# Loaders ##################################################################### + +class WindowsRegistryFinder: + + """Meta path finder for modules declared in the Windows registry.""" + + REGISTRY_KEY = ( + 'Software\\Python\\PythonCore\\{sys_version}' + '\\Modules\\{fullname}') + REGISTRY_KEY_DEBUG = ( + 'Software\\Python\\PythonCore\\{sys_version}' + '\\Modules\\{fullname}\\Debug') + DEBUG_BUILD = False # Changed in _setup() + + @classmethod + def _open_registry(cls, key): + try: + return _winreg.OpenKey(_winreg.HKEY_CURRENT_USER, key) + except OSError: + return _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE, key) + + @classmethod + def _search_registry(cls, fullname): + if cls.DEBUG_BUILD: + registry_key = cls.REGISTRY_KEY_DEBUG + else: + registry_key = cls.REGISTRY_KEY + key = registry_key.format(fullname=fullname, + sys_version=sys.version[:3]) + try: + with cls._open_registry(key) as hkey: + filepath = _winreg.QueryValue(hkey, '') + except OSError: + return None + return filepath + + @classmethod + def find_spec(cls, fullname, path=None, target=None): + filepath = cls._search_registry(fullname) + if filepath is None: + return None + try: + _path_stat(filepath) + except OSError: + return None + for loader, suffixes in _get_supported_file_loaders(): + if filepath.endswith(tuple(suffixes)): + spec = _bootstrap.spec_from_loader(fullname, + loader(fullname, filepath), + origin=filepath) + return spec + + @classmethod + def find_module(cls, fullname, path=None): + """Find module named in the registry. + + This method is deprecated. Use exec_module() instead. + + """ + spec = cls.find_spec(fullname, path) + if spec is not None: + return spec.loader + else: + return None + + +class _LoaderBasics: + + """Base class of common code needed by both SourceLoader and + SourcelessFileLoader.""" + + def is_package(self, fullname): + """Concrete implementation of InspectLoader.is_package by checking if + the path returned by get_filename has a filename of '__init__.py'.""" + filename = _path_split(self.get_filename(fullname))[1] + filename_base = filename.rsplit('.', 1)[0] + tail_name = fullname.rpartition('.')[2] + return filename_base == '__init__' and tail_name != '__init__' + + def create_module(self, spec): + """Use default semantics for module creation.""" + + def exec_module(self, module): + """Execute the module.""" + code = self.get_code(module.__name__) + if code is None: + raise ImportError('cannot load module {!r} when get_code() ' + 'returns None'.format(module.__name__)) + _bootstrap._call_with_frames_removed(exec, code, module.__dict__) + + def load_module(self, fullname): + return _bootstrap._load_module_shim(self, fullname) + + +class SourceLoader(_LoaderBasics): + + def path_mtime(self, path): + """Optional method that returns the modification time (an int) for the + specified path, where path is a str. + + Raises IOError when the path cannot be handled. + """ + raise IOError + + def path_stats(self, path): + """Optional method returning a metadata dict for the specified path + to by the path (str). + Possible keys: + - 'mtime' (mandatory) is the numeric timestamp of last source + code modification; + - 'size' (optional) is the size in bytes of the source code. + + Implementing this method allows the loader to read bytecode files. + Raises IOError when the path cannot be handled. + """ + return {'mtime': self.path_mtime(path)} + + def _cache_bytecode(self, source_path, cache_path, data): + """Optional method which writes data (bytes) to a file path (a str). + + Implementing this method allows for the writing of bytecode files. + + The source path is needed in order to correctly transfer permissions + """ + # For backwards compatibility, we delegate to set_data() + return self.set_data(cache_path, data) + + def set_data(self, path, data): + """Optional method which writes data (bytes) to a file path (a str). + + Implementing this method allows for the writing of bytecode files. + """ + + + def get_source(self, fullname): + """Concrete implementation of InspectLoader.get_source.""" + path = self.get_filename(fullname) + try: + source_bytes = self.get_data(path) + except OSError as exc: + raise ImportError('source not available through get_data()', + name=fullname) from exc + return decode_source(source_bytes) + + def source_to_code(self, data, path, *, _optimize=-1): + """Return the code object compiled from source. + + The 'data' argument can be any object type that compile() supports. + """ + return _bootstrap._call_with_frames_removed(compile, data, path, 'exec', + dont_inherit=True, optimize=_optimize) + + def get_code(self, fullname): + """Concrete implementation of InspectLoader.get_code. + + Reading of bytecode requires path_stats to be implemented. To write + bytecode, set_data must also be implemented. + + """ + source_path = self.get_filename(fullname) + source_mtime = None + try: + bytecode_path = cache_from_source(source_path) + except NotImplementedError: + bytecode_path = None + else: + try: + st = self.path_stats(source_path) + except IOError: + pass + else: + source_mtime = int(st['mtime']) + try: + data = self.get_data(bytecode_path) + except OSError: + pass + else: + try: + bytes_data = _validate_bytecode_header(data, + source_stats=st, name=fullname, + path=bytecode_path) + except (ImportError, EOFError): + pass + else: + _verbose_message('{} matches {}', bytecode_path, + source_path) + return _compile_bytecode(bytes_data, name=fullname, + bytecode_path=bytecode_path, + source_path=source_path) + source_bytes = self.get_data(source_path) + code_object = self.source_to_code(source_bytes, source_path) + _verbose_message('code object from {}', source_path) + if (not sys.dont_write_bytecode and bytecode_path is not None and + source_mtime is not None): + data = _code_to_bytecode(code_object, source_mtime, + len(source_bytes)) + try: + self._cache_bytecode(source_path, bytecode_path, data) + _verbose_message('wrote {!r}', bytecode_path) + except NotImplementedError: + pass + return code_object + + +class FileLoader: + + """Base file loader class which implements the loader protocol methods that + require file system usage.""" + + def __init__(self, fullname, path): + """Cache the module name and the path to the file found by the + finder.""" + self.name = fullname + self.path = path + + def __eq__(self, other): + return (self.__class__ == other.__class__ and + self.__dict__ == other.__dict__) + + def __hash__(self): + return hash(self.name) ^ hash(self.path) + + @_check_name + def load_module(self, fullname): + """Load a module from a file. + + This method is deprecated. Use exec_module() instead. + + """ + # The only reason for this method is for the name check. + # Issue #14857: Avoid the zero-argument form of super so the implementation + # of that form can be updated without breaking the frozen module + return super(FileLoader, self).load_module(fullname) + + @_check_name + def get_filename(self, fullname): + """Return the path to the source file as found by the finder.""" + return self.path + + def get_data(self, path): + """Return the data from path as raw bytes.""" + with _io.FileIO(path, 'r') as file: + return file.read() + + +class SourceFileLoader(FileLoader, SourceLoader): + + """Concrete implementation of SourceLoader using the file system.""" + + def path_stats(self, path): + """Return the metadata for the path.""" + st = _path_stat(path) + return {'mtime': st.st_mtime, 'size': st.st_size} + + def _cache_bytecode(self, source_path, bytecode_path, data): + # Adapt between the two APIs + mode = _calc_mode(source_path) + return self.set_data(bytecode_path, data, _mode=mode) + + def set_data(self, path, data, *, _mode=0o666): + """Write bytes data to a file.""" + parent, filename = _path_split(path) + path_parts = [] + # Figure out what directories are missing. + while parent and not _path_isdir(parent): + parent, part = _path_split(parent) + path_parts.append(part) + # Create needed directories. + for part in reversed(path_parts): + parent = _path_join(parent, part) + try: + _os.mkdir(parent) + except FileExistsError: + # Probably another Python process already created the dir. + continue + except OSError as exc: + # Could be a permission error, read-only filesystem: just forget + # about writing the data. + _verbose_message('could not create {!r}: {!r}', parent, exc) + return + try: + _write_atomic(path, data, _mode) + _verbose_message('created {!r}', path) + except OSError as exc: + # Same as above: just don't write the bytecode. + _verbose_message('could not create {!r}: {!r}', path, exc) + + +class SourcelessFileLoader(FileLoader, _LoaderBasics): + + """Loader which handles sourceless file imports.""" + + def get_code(self, fullname): + path = self.get_filename(fullname) + data = self.get_data(path) + bytes_data = _validate_bytecode_header(data, name=fullname, path=path) + return _compile_bytecode(bytes_data, name=fullname, bytecode_path=path) + + def get_source(self, fullname): + """Return None as there is no source code.""" + return None + + +# Filled in by _setup(). +EXTENSION_SUFFIXES = [] + + +class ExtensionFileLoader(FileLoader, _LoaderBasics): + + """Loader for extension modules. + + The constructor is designed to work with FileFinder. + + """ + + def __init__(self, name, path): + self.name = name + self.path = path + + def __eq__(self, other): + return (self.__class__ == other.__class__ and + self.__dict__ == other.__dict__) + + def __hash__(self): + return hash(self.name) ^ hash(self.path) + + def create_module(self, spec): + """Create an unitialized extension module""" + module = _bootstrap._call_with_frames_removed( + _imp.create_dynamic, spec) + _verbose_message('extension module {!r} loaded from {!r}', + spec.name, self.path) + return module + + def exec_module(self, module): + """Initialize an extension module""" + _bootstrap._call_with_frames_removed(_imp.exec_dynamic, module) + _verbose_message('extension module {!r} executed from {!r}', + self.name, self.path) + + def is_package(self, fullname): + """Return True if the extension module is a package.""" + file_name = _path_split(self.path)[1] + return any(file_name == '__init__' + suffix + for suffix in EXTENSION_SUFFIXES) + + def get_code(self, fullname): + """Return None as an extension module cannot create a code object.""" + return None + + def get_source(self, fullname): + """Return None as extension modules have no source code.""" + return None + + @_check_name + def get_filename(self, fullname): + """Return the path to the source file as found by the finder.""" + return self.path + + +class _NamespacePath: + """Represents a namespace package's path. It uses the module name + to find its parent module, and from there it looks up the parent's + __path__. When this changes, the module's own path is recomputed, + using path_finder. For top-level modules, the parent module's path + is sys.path.""" + + def __init__(self, name, path, path_finder): + self._name = name + self._path = path + self._last_parent_path = tuple(self._get_parent_path()) + self._path_finder = path_finder + + def _find_parent_path_names(self): + """Returns a tuple of (parent-module-name, parent-path-attr-name)""" + parent, dot, me = self._name.rpartition('.') + if dot == '': + # This is a top-level module. sys.path contains the parent path. + return 'sys', 'path' + # Not a top-level module. parent-module.__path__ contains the + # parent path. + return parent, '__path__' + + def _get_parent_path(self): + parent_module_name, path_attr_name = self._find_parent_path_names() + return getattr(sys.modules[parent_module_name], path_attr_name) + + def _recalculate(self): + # If the parent's path has changed, recalculate _path + parent_path = tuple(self._get_parent_path()) # Make a copy + if parent_path != self._last_parent_path: + spec = self._path_finder(self._name, parent_path) + # Note that no changes are made if a loader is returned, but we + # do remember the new parent path + if spec is not None and spec.loader is None: + if spec.submodule_search_locations: + self._path = spec.submodule_search_locations + self._last_parent_path = parent_path # Save the copy + return self._path + + def __iter__(self): + return iter(self._recalculate()) + + def __len__(self): + return len(self._recalculate()) + + def __repr__(self): + return '_NamespacePath({!r})'.format(self._path) + + def __contains__(self, item): + return item in self._recalculate() + + def append(self, item): + self._path.append(item) + + +# We use this exclusively in module_from_spec() for backward-compatibility. +class _NamespaceLoader: + def __init__(self, name, path, path_finder): + self._path = _NamespacePath(name, path, path_finder) + + @classmethod + def module_repr(cls, module): + """Return repr for the module. + + The method is deprecated. The import machinery does the job itself. + + """ + return '<module {!r} (namespace)>'.format(module.__name__) + + def is_package(self, fullname): + return True + + def get_source(self, fullname): + return '' + + def get_code(self, fullname): + return compile('', '<string>', 'exec', dont_inherit=True) + + def create_module(self, spec): + """Use default semantics for module creation.""" + + def exec_module(self, module): + pass + + def load_module(self, fullname): + """Load a namespace module. + + This method is deprecated. Use exec_module() instead. + + """ + # The import system never calls this method. + _verbose_message('namespace module loaded with path {!r}', self._path) + return _bootstrap._load_module_shim(self, fullname) + + +# Finders ##################################################################### + +class PathFinder: + + """Meta path finder for sys.path and package __path__ attributes.""" + + @classmethod + def invalidate_caches(cls): + """Call the invalidate_caches() method on all path entry finders + stored in sys.path_importer_caches (where implemented).""" + for finder in sys.path_importer_cache.values(): + if hasattr(finder, 'invalidate_caches'): + finder.invalidate_caches() + + @classmethod + def _path_hooks(cls, path): + """Search sequence of hooks for a finder for 'path'. + + If 'hooks' is false then use sys.path_hooks. + + """ + if sys.path_hooks is not None and not sys.path_hooks: + _warnings.warn('sys.path_hooks is empty', ImportWarning) + for hook in sys.path_hooks: + try: + return hook(path) + except ImportError: + continue + else: + return None + + @classmethod + def _path_importer_cache(cls, path): + """Get the finder for the path entry from sys.path_importer_cache. + + If the path entry is not in the cache, find the appropriate finder + and cache it. If no finder is available, store None. + + """ + if path == '': + try: + path = _os.getcwd() + except FileNotFoundError: + # Don't cache the failure as the cwd can easily change to + # a valid directory later on. + return None + try: + finder = sys.path_importer_cache[path] + except KeyError: + finder = cls._path_hooks(path) + sys.path_importer_cache[path] = finder + return finder + + @classmethod + def _legacy_get_spec(cls, fullname, finder): + # This would be a good place for a DeprecationWarning if + # we ended up going that route. + if hasattr(finder, 'find_loader'): + loader, portions = finder.find_loader(fullname) + else: + loader = finder.find_module(fullname) + portions = [] + if loader is not None: + return _bootstrap.spec_from_loader(fullname, loader) + spec = _bootstrap.ModuleSpec(fullname, None) + spec.submodule_search_locations = portions + return spec + + @classmethod + def _get_spec(cls, fullname, path, target=None): + """Find the loader or namespace_path for this module/package name.""" + # If this ends up being a namespace package, namespace_path is + # the list of paths that will become its __path__ + namespace_path = [] + for entry in path: + if not isinstance(entry, (str, bytes)): + continue + finder = cls._path_importer_cache(entry) + if finder is not None: + if hasattr(finder, 'find_spec'): + spec = finder.find_spec(fullname, target) + else: + spec = cls._legacy_get_spec(fullname, finder) + if spec is None: + continue + if spec.loader is not None: + return spec + portions = spec.submodule_search_locations + if portions is None: + raise ImportError('spec missing loader') + # This is possibly part of a namespace package. + # Remember these path entries (if any) for when we + # create a namespace package, and continue iterating + # on path. + namespace_path.extend(portions) + else: + spec = _bootstrap.ModuleSpec(fullname, None) + spec.submodule_search_locations = namespace_path + return spec + + @classmethod + def find_spec(cls, fullname, path=None, target=None): + """find the module on sys.path or 'path' based on sys.path_hooks and + sys.path_importer_cache.""" + if path is None: + path = sys.path + spec = cls._get_spec(fullname, path, target) + if spec is None: + return None + elif spec.loader is None: + namespace_path = spec.submodule_search_locations + if namespace_path: + # We found at least one namespace path. Return a + # spec which can create the namespace package. + spec.origin = 'namespace' + spec.submodule_search_locations = _NamespacePath(fullname, namespace_path, cls._get_spec) + return spec + else: + return None + else: + return spec + + @classmethod + def find_module(cls, fullname, path=None): + """find the module on sys.path or 'path' based on sys.path_hooks and + sys.path_importer_cache. + + This method is deprecated. Use find_spec() instead. + + """ + spec = cls.find_spec(fullname, path) + if spec is None: + return None + return spec.loader + + +class FileFinder: + + """File-based finder. + + Interactions with the file system are cached for performance, being + refreshed when the directory the finder is handling has been modified. + + """ + + def __init__(self, path, *loader_details): + """Initialize with the path to search on and a variable number of + 2-tuples containing the loader and the file suffixes the loader + recognizes.""" + loaders = [] + for loader, suffixes in loader_details: + loaders.extend((suffix, loader) for suffix in suffixes) + self._loaders = loaders + # Base (directory) path + self.path = path or '.' + self._path_mtime = -1 + self._path_cache = set() + self._relaxed_path_cache = set() + + def invalidate_caches(self): + """Invalidate the directory mtime.""" + self._path_mtime = -1 + + find_module = _find_module_shim + + def find_loader(self, fullname): + """Try to find a loader for the specified module, or the namespace + package portions. Returns (loader, list-of-portions). + + This method is deprecated. Use find_spec() instead. + + """ + spec = self.find_spec(fullname) + if spec is None: + return None, [] + return spec.loader, spec.submodule_search_locations or [] + + def _get_spec(self, loader_class, fullname, path, smsl, target): + loader = loader_class(fullname, path) + return spec_from_file_location(fullname, path, loader=loader, + submodule_search_locations=smsl) + + def find_spec(self, fullname, target=None): + """Try to find a loader for the specified module, or the namespace + package portions. Returns (loader, list-of-portions).""" + is_namespace = False + tail_module = fullname.rpartition('.')[2] + try: + mtime = _path_stat(self.path or _os.getcwd()).st_mtime + except OSError: + mtime = -1 + if mtime != self._path_mtime: + self._fill_cache() + self._path_mtime = mtime + # tail_module keeps the original casing, for __file__ and friends + if _relax_case(): + cache = self._relaxed_path_cache + cache_module = tail_module.lower() + else: + cache = self._path_cache + cache_module = tail_module + # Check if the module is the name of a directory (and thus a package). + if cache_module in cache: + base_path = _path_join(self.path, tail_module) + for suffix, loader_class in self._loaders: + init_filename = '__init__' + suffix + full_path = _path_join(base_path, init_filename) + if _path_isfile(full_path): + return self._get_spec(loader_class, fullname, full_path, [base_path], target) + else: + # If a namespace package, return the path if we don't + # find a module in the next section. + is_namespace = _path_isdir(base_path) + # Check for a file w/ a proper suffix exists. + for suffix, loader_class in self._loaders: + full_path = _path_join(self.path, tail_module + suffix) + _verbose_message('trying {}'.format(full_path), verbosity=2) + if cache_module + suffix in cache: + if _path_isfile(full_path): + return self._get_spec(loader_class, fullname, full_path, None, target) + if is_namespace: + _verbose_message('possible namespace for {}'.format(base_path)) + spec = _bootstrap.ModuleSpec(fullname, None) + spec.submodule_search_locations = [base_path] + return spec + return None + + def _fill_cache(self): + """Fill the cache of potential modules and packages for this directory.""" + path = self.path + try: + contents = _os.listdir(path or _os.getcwd()) + except (FileNotFoundError, PermissionError, NotADirectoryError): + # Directory has either been removed, turned into a file, or made + # unreadable. + contents = [] + # We store two cached versions, to handle runtime changes of the + # PYTHONCASEOK environment variable. + if not sys.platform.startswith('win'): + self._path_cache = set(contents) + else: + # Windows users can import modules with case-insensitive file + # suffixes (for legacy reasons). Make the suffix lowercase here + # so it's done once instead of for every import. This is safe as + # the specified suffixes to check against are always specified in a + # case-sensitive manner. + lower_suffix_contents = set() + for item in contents: + name, dot, suffix = item.partition('.') + if dot: + new_name = '{}.{}'.format(name, suffix.lower()) + else: + new_name = name + lower_suffix_contents.add(new_name) + self._path_cache = lower_suffix_contents + if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS): + self._relaxed_path_cache = {fn.lower() for fn in contents} + + @classmethod + def path_hook(cls, *loader_details): + """A class method which returns a closure to use on sys.path_hook + which will return an instance using the specified loaders and the path + called on the closure. + + If the path called on the closure is not a directory, ImportError is + raised. + + """ + def path_hook_for_FileFinder(path): + """Path hook for importlib.machinery.FileFinder.""" + if not _path_isdir(path): + raise ImportError('only directories are supported', path=path) + return cls(path, *loader_details) + + return path_hook_for_FileFinder + + def __repr__(self): + return 'FileFinder({!r})'.format(self.path) + + +# Import setup ############################################################### + +def _fix_up_module(ns, name, pathname, cpathname=None): + # This function is used by PyImport_ExecCodeModuleObject(). + loader = ns.get('__loader__') + spec = ns.get('__spec__') + if not loader: + if spec: + loader = spec.loader + elif pathname == cpathname: + loader = SourcelessFileLoader(name, pathname) + else: + loader = SourceFileLoader(name, pathname) + if not spec: + spec = spec_from_file_location(name, pathname, loader=loader) + try: + ns['__spec__'] = spec + ns['__loader__'] = loader + ns['__file__'] = pathname + ns['__cached__'] = cpathname + except Exception: + # Not important enough to report. + pass + + +def _get_supported_file_loaders(): + """Returns a list of file-based module loaders. + + Each item is a tuple (loader, suffixes). + """ + extensions = ExtensionFileLoader, _imp.extension_suffixes() + source = SourceFileLoader, SOURCE_SUFFIXES + bytecode = SourcelessFileLoader, BYTECODE_SUFFIXES + return [extensions, source, bytecode] + + +def _setup(_bootstrap_module): + """Setup the path-based importers for importlib by importing needed + built-in modules and injecting them into the global namespace. + + Other components are extracted from the core bootstrap module. + + """ + global sys, _imp, _bootstrap + _bootstrap = _bootstrap_module + sys = _bootstrap.sys + _imp = _bootstrap._imp + + # Directly load built-in modules needed during bootstrap. + self_module = sys.modules[__name__] + for builtin_name in ('_io', '_warnings', 'builtins', 'marshal'): + if builtin_name not in sys.modules: + builtin_module = _bootstrap._builtin_from_name(builtin_name) + else: + builtin_module = sys.modules[builtin_name] + setattr(self_module, builtin_name, builtin_module) + + # Directly load the os module (needed during bootstrap). + os_details = ('posix', ['/']), ('nt', ['\\', '/']) + for builtin_os, path_separators in os_details: + # Assumption made in _path_join() + assert all(len(sep) == 1 for sep in path_separators) + path_sep = path_separators[0] + if builtin_os in sys.modules: + os_module = sys.modules[builtin_os] + break + else: + try: + os_module = _bootstrap._builtin_from_name(builtin_os) + break + except ImportError: + continue + else: + raise ImportError('importlib requires posix or nt') + setattr(self_module, '_os', os_module) + setattr(self_module, 'path_sep', path_sep) + setattr(self_module, 'path_separators', ''.join(path_separators)) + + # Directly load the _thread module (needed during bootstrap). + try: + thread_module = _bootstrap._builtin_from_name('_thread') + except ImportError: + # Python was built without threads + thread_module = None + setattr(self_module, '_thread', thread_module) + + # Directly load the _weakref module (needed during bootstrap). + weakref_module = _bootstrap._builtin_from_name('_weakref') + setattr(self_module, '_weakref', weakref_module) + + # Directly load the winreg module (needed during bootstrap). + if builtin_os == 'nt': + winreg_module = _bootstrap._builtin_from_name('winreg') + setattr(self_module, '_winreg', winreg_module) + + # Constants + setattr(self_module, '_relax_case', _make_relax_case()) + EXTENSION_SUFFIXES.extend(_imp.extension_suffixes()) + if builtin_os == 'nt': + SOURCE_SUFFIXES.append('.pyw') + if '_d.pyd' in EXTENSION_SUFFIXES: + WindowsRegistryFinder.DEBUG_BUILD = True + + +def _install(_bootstrap_module): + """Install the path-based import components.""" + _setup(_bootstrap_module) + supported_loaders = _get_supported_file_loaders() + sys.path_hooks.extend([FileFinder.path_hook(*supported_loaders)]) + if _os.__name__ == 'nt': + sys.meta_path.append(WindowsRegistryFinder) + sys.meta_path.append(PathFinder) + + # XXX We expose a couple of classes in _bootstrap for the sake of + # a setuptools bug (https://bitbucket.org/pypa/setuptools/issue/378). + _bootstrap_module.FileFinder = FileFinder + _bootstrap_module.SourceFileLoader = SourceFileLoader |