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📁 ..	-	2025-10-13 08:00
📄 __init__.py """A pure Python implementation of import.""" __all__ = ['__import__', 'import_module', 'invalidate_caches', 'reload'] # Bootstrap help ##################################################### # Until bootstrapping is complete, DO NOT import any modules that attempt # to import importlib._bootstrap (directly or indirectly). Since this # partially initialised package would be present in sys.modules, those # modules would get an uninitialised copy of the source version, instead # of a fully initialised version (either the frozen one or the one # initialised below if the frozen one is not available). import _imp # Just the builtin component, NOT the full Python module import sys try: import _frozen_importlib as _bootstrap except ImportError: from . import _bootstrap _bootstrap._setup(sys, _imp) else: # importlib._bootstrap is the built-in import, ensure we don't create # a second copy of the module. _bootstrap.__name__ = 'importlib._bootstrap' _bootstrap.__package__ = 'importlib' try: _bootstrap.__file__ = __file__.replace('__init__.py', '_bootstrap.py') except NameError: # __file__ is not guaranteed to be defined, e.g. if this code gets # frozen by a tool like cx_Freeze. pass sys.modules['importlib._bootstrap'] = _bootstrap try: import _frozen_importlib_external as _bootstrap_external except ImportError: from . import _bootstrap_external _bootstrap_external._setup(_bootstrap) _bootstrap._bootstrap_external = _bootstrap_external else: _bootstrap_external.__name__ = 'importlib._bootstrap_external' _bootstrap_external.__package__ = 'importlib' try: _bootstrap_external.__file__ = __file__.replace('__init__.py', '_bootstrap_external.py') except NameError: # __file__ is not guaranteed to be defined, e.g. if this code gets # frozen by a tool like cx_Freeze. pass sys.modules['importlib._bootstrap_external'] = _bootstrap_external # To simplify imports in test code _w_long = _bootstrap_external._w_long _r_long = _bootstrap_external._r_long # Fully bootstrapped at this point, import whatever you like, circular # dependencies and startup overhead minimisation permitting :) import types import warnings # Public API ######################################################### from ._bootstrap import __import__ def invalidate_caches(): """Call the invalidate_caches() method on all meta path finders stored in sys.meta_path (where implemented).""" for finder in sys.meta_path: if hasattr(finder, 'invalidate_caches'): finder.invalidate_caches() def find_loader(name, path=None): """Return the loader for the specified module. This is a backward-compatible wrapper around find_spec(). This function is deprecated in favor of importlib.util.find_spec(). """ warnings.warn('Deprecated since Python 3.4. ' 'Use importlib.util.find_spec() instead.', DeprecationWarning, stacklevel=2) try: loader = sys.modules[name].__loader__ if loader is None: raise ValueError('{}.__loader__ is None'.format(name)) else: return loader except KeyError: pass except AttributeError: raise ValueError('{}.__loader__ is not set'.format(name)) from None spec = _bootstrap._find_spec(name, path) # We won't worry about malformed specs (missing attributes). if spec is None: return None if spec.loader is None: if spec.submodule_search_locations is None: raise ImportError('spec for {} missing loader'.format(name), name=name) raise ImportError('namespace packages do not have loaders', name=name) return spec.loader def import_module(name, package=None): """Import a module. The 'package' argument is required when performing a relative import. It specifies the package to use as the anchor point from which to resolve the relative import to an absolute import. """ level = 0 if name.startswith('.'): if not package: msg = ("the 'package' argument is required to perform a relative " "import for {!r}") raise TypeError(msg.format(name)) for character in name: if character != '.': break level += 1 return _bootstrap._gcd_import(name[level:], package, level) _RELOADING = {} def reload(module): """Reload the module and return it. The module must have been successfully imported before. """ if not module or not isinstance(module, types.ModuleType): raise TypeError("reload() argument must be a module") try: name = module.__spec__.name except AttributeError: name = module.__name__ if sys.modules.get(name) is not module: msg = "module {} not in sys.modules" raise ImportError(msg.format(name), name=name) if name in _RELOADING: return _RELOADING[name] _RELOADING[name] = module try: parent_name = name.rpartition('.')[0] if parent_name: try: parent = sys.modules[parent_name] except KeyError: msg = "parent {!r} not in sys.modules" raise ImportError(msg.format(parent_name), name=parent_name) from None else: pkgpath = parent.__path__ else: pkgpath = None target = module spec = module.__spec__ = _bootstrap._find_spec(name, pkgpath, target) if spec is None: raise ModuleNotFoundError(f"spec not found for the module {name!r}", name=name) _bootstrap._exec(spec, module) # The module may have replaced itself in sys.modules! return sys.modules[name] finally: try: del _RELOADING[name] except KeyError: pass	5.9 KB	2024-04-17 17:55
📁 __pycache__	-	2025-10-13 08:00
📄 _bootstrap.py """Core implementation of 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 ###################################################### _bootstrap_external = None def _wrap(new, old): """Simple substitute for functools.update_wrapper.""" for replace in ['__module__', '__name__', '__qualname__', '__doc__']: if hasattr(old, replace): setattr(new, replace, getattr(old, replace)) new.__dict__.update(old.__dict__) def _new_module(name): return type(sys)(name) # Module-level locking ######################################################## # A dict mapping module names to weakrefs of _ModuleLock instances # Dictionary protected by the global import lock _module_locks = {} # A dict mapping thread ids to _ModuleLock instances _blocking_on = {} class _DeadlockError(RuntimeError): pass class _ModuleLock: """A recursive lock implementation which is able to detect deadlocks (e.g. thread 1 trying to take locks A then B, and thread 2 trying to take locks B then A). """ def __init__(self, name): self.lock = _thread.allocate_lock() self.wakeup = _thread.allocate_lock() self.name = name self.owner = None self.count = 0 self.waiters = 0 def has_deadlock(self): # Deadlock avoidance for concurrent circular imports. me = _thread.get_ident() tid = self.owner while True: lock = _blocking_on.get(tid) if lock is None: return False tid = lock.owner if tid == me: return True def acquire(self): """ Acquire the module lock. If a potential deadlock is detected, a _DeadlockError is raised. Otherwise, the lock is always acquired and True is returned. """ tid = _thread.get_ident() _blocking_on[tid] = self try: while True: with self.lock: if self.count == 0 or self.owner == tid: self.owner = tid self.count += 1 return True if self.has_deadlock(): raise _DeadlockError('deadlock detected by %r' % self) if self.wakeup.acquire(False): self.waiters += 1 # Wait for a release() call self.wakeup.acquire() self.wakeup.release() finally: del _blocking_on[tid] def release(self): tid = _thread.get_ident() with self.lock: if self.owner != tid: raise RuntimeError('cannot release un-acquired lock') assert self.count > 0 self.count -= 1 if self.count == 0: self.owner = None if self.waiters: self.waiters -= 1 self.wakeup.release() def __repr__(self): return '_ModuleLock({!r}) at {}'.format(self.name, id(self)) class _DummyModuleLock: """A simple _ModuleLock equivalent for Python builds without multi-threading support.""" def __init__(self, name): self.name = name self.count = 0 def acquire(self): self.count += 1 return True def release(self): if self.count == 0: raise RuntimeError('cannot release un-acquired lock') self.count -= 1 def __repr__(self): return '_DummyModuleLock({!r}) at {}'.format(self.name, id(self)) class _ModuleLockManager: def __init__(self, name): self._name = name self._lock = None def __enter__(self): self._lock = _get_module_lock(self._name) self._lock.acquire() def __exit__(self, args, kwargs): self._lock.release() # The following two functions are for consumption by Python/import.c. def _get_module_lock(name): """Get or create the module lock for a given module name. Acquire/release internally the global import lock to protect _module_locks.""" _imp.acquire_lock() try: try: lock = _module_locks[name]() except KeyError: lock = None if lock is None: if _thread is None: lock = _DummyModuleLock(name) else: lock = _ModuleLock(name) def cb(ref, name=name): _imp.acquire_lock() try: # bpo-31070: Check if another thread created a new lock # after the previous lock was destroyed # but before the weakref callback was called. if _module_locks.get(name) is ref: del _module_locks[name] finally: _imp.release_lock() _module_locks[name] = _weakref.ref(lock, cb) finally: _imp.release_lock() return lock def _lock_unlock_module(name): """Acquires then releases the module lock for a given module name. This is used to ensure a module is completely initialized, in the event it is being imported by another thread. """ lock = _get_module_lock(name) try: lock.acquire() except _DeadlockError: # Concurrent circular import, we'll accept a partially initialized # module object. pass else: lock.release() # Frame stripping magic ############################################### def _call_with_frames_removed(f, args, *kwds): """remove_importlib_frames in import.c will always remove sequences of importlib frames that end with a call to this function Use it instead of a normal call in places where including the importlib frames introduces unwanted noise into the traceback (e.g. when executing module code) """ return f(args, *kwds) 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 _requires_builtin(fxn): """Decorator to verify the named module is built-in.""" def _requires_builtin_wrapper(self, fullname): if fullname not in sys.builtin_module_names: raise ImportError('{!r} is not a built-in module'.format(fullname), name=fullname) return fxn(self, fullname) _wrap(_requires_builtin_wrapper, fxn) return _requires_builtin_wrapper def _requires_frozen(fxn): """Decorator to verify the named module is frozen.""" def _requires_frozen_wrapper(self, fullname): if not _imp.is_frozen(fullname): raise ImportError('{!r} is not a frozen module'.format(fullname), name=fullname) return fxn(self, fullname) _wrap(_requires_frozen_wrapper, fxn) return _requires_frozen_wrapper # Typically used by loader classes as a method replacement. def _load_module_shim(self, fullname): """Load the specified module into sys.modules and return it. This method is deprecated. Use loader.exec_module instead. """ spec = spec_from_loader(fullname, self) if fullname in sys.modules: module = sys.modules[fullname] _exec(spec, module) return sys.modules[fullname] else: return _load(spec) # Module specifications ####################################################### def _module_repr(module): # The implementation of ModuleType.__repr__(). loader = getattr(module, '__loader__', None) if hasattr(loader, 'module_repr'): # As soon as BuiltinImporter, FrozenImporter, and NamespaceLoader # drop their implementations for module_repr. we can add a # deprecation warning here. try: return loader.module_repr(module) except Exception: pass try: spec = module.__spec__ except AttributeError: pass else: if spec is not None: return _module_repr_from_spec(spec) # We could use module.__class__.__name__ instead of 'module' in the # various repr permutations. try: name = module.__name__ except AttributeError: name = '?' try: filename = module.__file__ except AttributeError: if loader is None: return '<module {!r}>'.format(name) else: return '<module {!r} ({!r})>'.format(name, loader) else: return '<module {!r} from {!r}>'.format(name, filename) class _installed_safely: def __init__(self, module): self._module = module self._spec = module.__spec__ def __enter__(self): # This must be done before putting the module in sys.modules # (otherwise an optimization shortcut in import.c becomes # wrong) self._spec._initializing = True sys.modules[self._spec.name] = self._module def __exit__(self, args): try: spec = self._spec if any(arg is not None for arg in args): try: del sys.modules[spec.name] except KeyError: pass else: _verbose_message('import {!r} # {!r}', spec.name, spec.loader) finally: self._spec._initializing = False class ModuleSpec: """The specification for a module, used for loading. A module's spec is the source for information about the module. For data associated with the module, including source, use the spec's loader. `name` is the absolute name of the module. `loader` is the loader to use when loading the module. `parent` is the name of the package the module is in. The parent is derived from the name. `is_package` determines if the module is considered a package or not. On modules this is reflected by the `__path__` attribute. `origin` is the specific location used by the loader from which to load the module, if that information is available. When filename is set, origin will match. `has_location` indicates that a spec's "origin" reflects a location. When this is True, `__file__` attribute of the module is set. `cached` is the location of the cached bytecode file, if any. It corresponds to the `__cached__` attribute. `submodule_search_locations` is the sequence of path entries to search when importing submodules. If set, is_package should be True--and False otherwise. Packages are simply modules that (may) have submodules. If a spec has a non-None value in `submodule_search_locations`, the import system will consider modules loaded from the spec as packages. Only finders (see importlib.abc.MetaPathFinder and importlib.abc.PathEntryFinder) should modify ModuleSpec instances. """ def __init__(self, name, loader, , origin=None, loader_state=None, is_package=None): self.name = name self.loader = loader self.origin = origin self.loader_state = loader_state self.submodule_search_locations = [] if is_package else None # file-location attributes self._set_fileattr = False self._cached = None def __repr__(self): args = ['name={!r}'.format(self.name), 'loader={!r}'.format(self.loader)] if self.origin is not None: args.append('origin={!r}'.format(self.origin)) if self.submodule_search_locations is not None: args.append('submodule_search_locations={}' .format(self.submodule_search_locations)) return '{}({})'.format(self.__class__.__name__, ', '.join(args)) def __eq__(self, other): smsl = self.submodule_search_locations try: return (self.name == other.name and self.loader == other.loader and self.origin == other.origin and smsl == other.submodule_search_locations and self.cached == other.cached and self.has_location == other.has_location) except AttributeError: return False @property def cached(self): if self._cached is None: if self.origin is not None and self._set_fileattr: if _bootstrap_external is None: raise NotImplementedError self._cached = _bootstrap_external._get_cached(self.origin) return self._cached @cached.setter def cached(self, cached): self._cached = cached @property def parent(self): """The name of the module's parent.""" if self.submodule_search_locations is None: return self.name.rpartition('.')[0] else: return self.name @property def has_location(self): return self._set_fileattr @has_location.setter def has_location(self, value): self._set_fileattr = bool(value) def spec_from_loader(name, loader, , origin=None, is_package=None): """Return a module spec based on various loader methods.""" if hasattr(loader, 'get_filename'): if _bootstrap_external is None: raise NotImplementedError spec_from_file_location = _bootstrap_external.spec_from_file_location if is_package is None: return spec_from_file_location(name, loader=loader) search = [] if is_package else None return spec_from_file_location(name, loader=loader, submodule_search_locations=search) if is_package is None: if hasattr(loader, 'is_package'): try: is_package = loader.is_package(name) except ImportError: is_package = None # aka, undefined else: # the default is_package = False return ModuleSpec(name, loader, origin=origin, is_package=is_package) def _spec_from_module(module, loader=None, origin=None): # This function is meant for use in _setup(). try: spec = module.__spec__ except AttributeError: pass else: if spec is not None: return spec name = module.__name__ if loader is None: try: loader = module.__loader__ except AttributeError: # loader will stay None. pass try: location = module.__file__ except AttributeError: location = None if origin is None: if location is None: try: origin = loader._ORIGIN except AttributeError: origin = None else: origin = location try: cached = module.__cached__ except AttributeError: cached = None try: submodule_search_locations = list(module.__path__) except AttributeError: submodule_search_locations = None spec = ModuleSpec(name, loader, origin=origin) spec._set_fileattr = False if location is None else True spec.cached = cached spec.submodule_search_locations = submodule_search_locations return spec def _init_module_attrs(spec, module, , override=False): # The passed-in module may be not support attribute assignment, # in which case we simply don't set the attributes. # __name__ if (override or getattr(module, '__name__', None) is None): try: module.__name__ = spec.name except AttributeError: pass # __loader__ if override or getattr(module, '__loader__', None) is None: loader = spec.loader if loader is None: # A backward compatibility hack. if spec.submodule_search_locations is not None: if _bootstrap_external is None: raise NotImplementedError _NamespaceLoader = _bootstrap_external._NamespaceLoader loader = _NamespaceLoader.__new__(_NamespaceLoader) loader._path = spec.submodule_search_locations spec.loader = loader # While the docs say that module.__file__ is not set for # built-in modules, and the code below will avoid setting it if # spec.has_location is false, this is incorrect for namespace # packages. Namespace packages have no location, but their # __spec__.origin is None, and thus their module.__file__ # should also be None for consistency. While a bit of a hack, # this is the best place to ensure this consistency. # # See # https://docs.python.org/3/library/importlib.html#importlib.abc.Loader.load_module # and bpo-32305 module.__file__ = None try: module.__loader__ = loader except AttributeError: pass # __package__ if override or getattr(module, '__package__', None) is None: try: module.__package__ = spec.parent except AttributeError: pass # __spec__ try: module.__spec__ = spec except AttributeError: pass # __path__ if override or getattr(module, '__path__', None) is None: if spec.submodule_search_locations is not None: try: module.__path__ = spec.submodule_search_locations except AttributeError: pass # __file__/__cached__ if spec.has_location: if override or getattr(module, '__file__', None) is None: try: module.__file__ = spec.origin except AttributeError: pass if override or getattr(module, '__cached__', None) is None: if spec.cached is not None: try: module.__cached__ = spec.cached except AttributeError: pass return module def module_from_spec(spec): """Create a module based on the provided spec.""" # Typically loaders will not implement create_module(). module = None if hasattr(spec.loader, 'create_module'): # If create_module() returns `None` then it means default # module creation should be used. module = spec.loader.create_module(spec) elif hasattr(spec.loader, 'exec_module'): raise ImportError('loaders that define exec_module() ' 'must also define create_module()') if module is None: module = _new_module(spec.name) _init_module_attrs(spec, module) return module def _module_repr_from_spec(spec): """Return the repr to use for the module.""" # We mostly replicate _module_repr() using the spec attributes. name = '?' if spec.name is None else spec.name if spec.origin is None: if spec.loader is None: return '<module {!r}>'.format(name) else: return '<module {!r} ({!r})>'.format(name, spec.loader) else: if spec.has_location: return '<module {!r} from {!r}>'.format(name, spec.origin) else: return '<module {!r} ({})>'.format(spec.name, spec.origin) # Used by importlib.reload() and _load_module_shim(). def _exec(spec, module): """Execute the spec's specified module in an existing module's namespace.""" name = spec.name with _ModuleLockManager(name): if sys.modules.get(name) is not module: msg = 'module {!r} not in sys.modules'.format(name) raise ImportError(msg, name=name) if spec.loader is None: if spec.submodule_search_locations is None: raise ImportError('missing loader', name=spec.name) # namespace package _init_module_attrs(spec, module, override=True) return module _init_module_attrs(spec, module, override=True) if not hasattr(spec.loader, 'exec_module'): # (issue19713) Once BuiltinImporter and ExtensionFileLoader # have exec_module() implemented, we can add a deprecation # warning here. spec.loader.load_module(name) else: spec.loader.exec_module(module) return sys.modules[name] def _load_backward_compatible(spec): # (issue19713) Once BuiltinImporter and ExtensionFileLoader # have exec_module() implemented, we can add a deprecation # warning here. spec.loader.load_module(spec.name) # The module must be in sys.modules at this point! module = sys.modules[spec.name] if getattr(module, '__loader__', None) is None: try: module.__loader__ = spec.loader except AttributeError: pass if getattr(module, '__package__', None) is None: try: # Since module.__path__ may not line up with # spec.submodule_search_paths, we can't necessarily rely # on spec.parent here. module.__package__ = module.__name__ if not hasattr(module, '__path__'): module.__package__ = spec.name.rpartition('.')[0] except AttributeError: pass if getattr(module, '__spec__', None) is None: try: module.__spec__ = spec except AttributeError: pass return module def _load_unlocked(spec): # A helper for direct use by the import system. if spec.loader is not None: # not a namespace package if not hasattr(spec.loader, 'exec_module'): return _load_backward_compatible(spec) module = module_from_spec(spec) with _installed_safely(module): if spec.loader is None: if spec.submodule_search_locations is None: raise ImportError('missing loader', name=spec.name) # A namespace package so do nothing. else: spec.loader.exec_module(module) # We don't ensure that the import-related module attributes get # set in the sys.modules replacement case. Such modules are on # their own. return sys.modules[spec.name] # A method used during testing of _load_unlocked() and by # _load_module_shim(). def _load(spec): """Return a new module object, loaded by the spec's loader. The module is not added to its parent. If a module is already in sys.modules, that existing module gets clobbered. """ with _ModuleLockManager(spec.name): return _load_unlocked(spec) # Loaders ##################################################################### class BuiltinImporter: """Meta path import for built-in modules. All methods are either class or static methods to avoid the need to instantiate the class. """ @staticmethod def module_repr(module): """Return repr for the module. The method is deprecated. The import machinery does the job itself. """ return '<module {!r} (built-in)>'.format(module.__name__) @classmethod def find_spec(cls, fullname, path=None, target=None): if path is not None: return None if _imp.is_builtin(fullname): return spec_from_loader(fullname, cls, origin='built-in') else: return None @classmethod def find_module(cls, fullname, path=None): """Find the built-in module. If 'path' is ever specified then the search is considered a failure. This method is deprecated. Use find_spec() instead. """ spec = cls.find_spec(fullname, path) return spec.loader if spec is not None else None @classmethod def create_module(self, spec): """Create a built-in module""" if spec.name not in sys.builtin_module_names: raise ImportError('{!r} is not a built-in module'.format(spec.name), name=spec.name) return _call_with_frames_removed(_imp.create_builtin, spec) @classmethod def exec_module(self, module): """Exec a built-in module""" _call_with_frames_removed(_imp.exec_builtin, module) @classmethod @_requires_builtin def get_code(cls, fullname): """Return None as built-in modules do not have code objects.""" return None @classmethod @_requires_builtin def get_source(cls, fullname): """Return None as built-in modules do not have source code.""" return None @classmethod @_requires_builtin def is_package(cls, fullname): """Return False as built-in modules are never packages.""" return False load_module = classmethod(_load_module_shim) class FrozenImporter: """Meta path import for frozen modules. All methods are either class or static methods to avoid the need to instantiate the class. """ @staticmethod def module_repr(m): """Return repr for the module. The method is deprecated. The import machinery does the job itself. """ return '<module {!r} (frozen)>'.format(m.__name__) @classmethod def find_spec(cls, fullname, path=None, target=None): if _imp.is_frozen(fullname): return spec_from_loader(fullname, cls, origin='frozen') else: return None @classmethod def find_module(cls, fullname, path=None): """Find a frozen module. This method is deprecated. Use find_spec() instead. """ return cls if _imp.is_frozen(fullname) else None @classmethod def create_module(cls, spec): """Use default semantics for module creation.""" @staticmethod def exec_module(module): name = module.__spec__.name if not _imp.is_frozen(name): raise ImportError('{!r} is not a frozen module'.format(name), name=name) code = _call_with_frames_removed(_imp.get_frozen_object, name) exec(code, module.__dict__) @classmethod def load_module(cls, fullname): """Load a frozen module. This method is deprecated. Use exec_module() instead. """ return _load_module_shim(cls, fullname) @classmethod @_requires_frozen def get_code(cls, fullname): """Return the code object for the frozen module.""" return _imp.get_frozen_object(fullname) @classmethod @_requires_frozen def get_source(cls, fullname): """Return None as frozen modules do not have source code.""" return None @classmethod @_requires_frozen def is_package(cls, fullname): """Return True if the frozen module is a package.""" return _imp.is_frozen_package(fullname) # Import itself ############################################################### class _ImportLockContext: """Context manager for the import lock.""" def __enter__(self): """Acquire the import lock.""" _imp.acquire_lock() def __exit__(self, exc_type, exc_value, exc_traceback): """Release the import lock regardless of any raised exceptions.""" _imp.release_lock() def _resolve_name(name, package, level): """Resolve a relative module name to an absolute one.""" bits = package.rsplit('.', level - 1) if len(bits) < level: raise ValueError('attempted relative import beyond top-level package') base = bits[0] return '{}.{}'.format(base, name) if name else base def _find_spec_legacy(finder, name, path): # This would be a good place for a DeprecationWarning if # we ended up going that route. loader = finder.find_module(name, path) if loader is None: return None return spec_from_loader(name, loader) def _find_spec(name, path, target=None): """Find a module's spec.""" meta_path = sys.meta_path if meta_path is None: # PyImport_Cleanup() is running or has been called. raise ImportError("sys.meta_path is None, Python is likely " "shutting down") if not meta_path: _warnings.warn('sys.meta_path is empty', ImportWarning) # We check sys.modules here for the reload case. While a passed-in # target will usually indicate a reload there is no guarantee, whereas # sys.modules provides one. is_reload = name in sys.modules for finder in meta_path: with _ImportLockContext(): try: find_spec = finder.find_spec except AttributeError: spec = _find_spec_legacy(finder, name, path) if spec is None: continue else: spec = find_spec(name, path, target) if spec is not None: # The parent import may have already imported this module. if not is_reload and name in sys.modules: module = sys.modules[name] try: __spec__ = module.__spec__ except AttributeError: # We use the found spec since that is the one that # we would have used if the parent module hadn't # beaten us to the punch. return spec else: if __spec__ is None: return spec else: return __spec__ else: return spec else: return None def _sanity_check(name, package, level): """Verify arguments are "sane".""" if not isinstance(name, str): raise TypeError('module name must be str, not {}'.format(type(name))) if level < 0: raise ValueError('level must be >= 0') if level > 0: if not isinstance(package, str): raise TypeError('__package__ not set to a string') elif not package: raise ImportError('attempted relative import with no known parent ' 'package') if not name and level == 0: raise ValueError('Empty module name') _ERR_MSG_PREFIX = 'No module named ' _ERR_MSG = _ERR_MSG_PREFIX + '{!r}' def _find_and_load_unlocked(name, import_): path = None parent = name.rpartition('.')[0] if parent: if parent not in sys.modules: _call_with_frames_removed(import_, parent) # Crazy side-effects! if name in sys.modules: return sys.modules[name] parent_module = sys.modules[parent] try: path = parent_module.__path__ except AttributeError: msg = (_ERR_MSG + '; {!r} is not a package').format(name, parent) raise ModuleNotFoundError(msg, name=name) from None spec = _find_spec(name, path) if spec is None: raise ModuleNotFoundError(_ERR_MSG.format(name), name=name) else: module = _load_unlocked(spec) if parent: # Set the module as an attribute on its parent. parent_module = sys.modules[parent] setattr(parent_module, name.rpartition('.')[2], module) return module _NEEDS_LOADING = object() def _find_and_load(name, import_): """Find and load the module.""" with _ModuleLockManager(name): module = sys.modules.get(name, _NEEDS_LOADING) if module is _NEEDS_LOADING: return _find_and_load_unlocked(name, import_) if module is None: message = ('import of {} halted; ' 'None in sys.modules'.format(name)) raise ModuleNotFoundError(message, name=name) _lock_unlock_module(name) return module def _gcd_import(name, package=None, level=0): """Import and return the module based on its name, the package the call is being made from, and the level adjustment. This function represents the greatest common denominator of functionality between import_module and __import__. This includes setting __package__ if the loader did not. """ _sanity_check(name, package, level) if level > 0: name = _resolve_name(name, package, level) return _find_and_load(name, _gcd_import) def _handle_fromlist(module, fromlist, import_, , recursive=False): """Figure out what __import__ should return. The import_ parameter is a callable which takes the name of module to import. It is required to decouple the function from assuming importlib's import implementation is desired. """ # The hell that is fromlist ... # If a package was imported, try to import stuff from fromlist. if hasattr(module, '__path__'): for x in fromlist: if not isinstance(x, str): if recursive: where = module.__name__ + '.__all__' else: where = "``from list''" raise TypeError(f"Item in {where} must be str, " f"not {type(x).__name__}") elif x == '*': if not recursive and hasattr(module, '__all__'): _handle_fromlist(module, module.__all__, import_, recursive=True) elif not hasattr(module, x): from_name = '{}.{}'.format(module.__name__, x) try: _call_with_frames_removed(import_, from_name) except ModuleNotFoundError as exc: # Backwards-compatibility dictates we ignore failed # imports triggered by fromlist for modules that don't # exist. if (exc.name == from_name and sys.modules.get(from_name, _NEEDS_LOADING) is not None): continue raise return module def _calc___package__(globals): """Calculate what __package__ should be. __package__ is not guaranteed to be defined or could be set to None to represent that its proper value is unknown. """ package = globals.get('__package__') spec = globals.get('__spec__') if package is not None: if spec is not None and package != spec.parent: _warnings.warn("__package__ != __spec__.parent " f"({package!r} != {spec.parent!r})", ImportWarning, stacklevel=3) return package elif spec is not None: return spec.parent else: _warnings.warn("can't resolve package from __spec__ or __package__, " "falling back on __name__ and __path__", ImportWarning, stacklevel=3) package = globals['__name__'] if '__path__' not in globals: package = package.rpartition('.')[0] return package def __import__(name, globals=None, locals=None, fromlist=(), level=0): """Import a module. The 'globals' argument is used to infer where the import is occurring from to handle relative imports. The 'locals' argument is ignored. The 'fromlist' argument specifies what should exist as attributes on the module being imported (e.g. ``from module import <fromlist>``). The 'level' argument represents the package location to import from in a relative import (e.g. ``from ..pkg import mod`` would have a 'level' of 2). """ if level == 0: module = _gcd_import(name) else: globals_ = globals if globals is not None else {} package = _calc___package__(globals_) module = _gcd_import(name, package, level) if not fromlist: # Return up to the first dot in 'name'. This is complicated by the fact # that 'name' may be relative. if level == 0: return _gcd_import(name.partition('.')[0]) elif not name: return module else: # Figure out where to slice the module's name up to the first dot # in 'name'. cut_off = len(name) - len(name.partition('.')[0]) # Slice end needs to be positive to alleviate need to special-case # when ``'.' not in name``. return sys.modules[module.__name__[:len(module.__name__)-cut_off]] else: return _handle_fromlist(module, fromlist, _gcd_import) def _builtin_from_name(name): spec = BuiltinImporter.find_spec(name) if spec is None: raise ImportError('no built-in module named ' + name) return _load_unlocked(spec) def _setup(sys_module, _imp_module): """Setup importlib by importing needed built-in modules and injecting them into the global namespace. As sys is needed for sys.modules access and _imp is needed to load built-in modules, those two modules must be explicitly passed in. """ global _imp, sys _imp = _imp_module sys = sys_module # Set up the spec for existing builtin/frozen modules. module_type = type(sys) for name, module in sys.modules.items(): if isinstance(module, module_type): if name in sys.builtin_module_names: loader = BuiltinImporter elif _imp.is_frozen(name): loader = FrozenImporter else: continue spec = _spec_from_module(module, loader) _init_module_attrs(spec, module) # Directly load built-in modules needed during bootstrap. self_module = sys.modules[__name__] for builtin_name in ('_thread', '_warnings', '_weakref'): if builtin_name not in sys.modules: builtin_module = _builtin_from_name(builtin_name) else: builtin_module = sys.modules[builtin_name] setattr(self_module, builtin_name, builtin_module) def _install(sys_module, _imp_module): """Install importers for builtin and frozen modules""" _setup(sys_module, _imp_module) sys.meta_path.append(BuiltinImporter) sys.meta_path.append(FrozenImporter) def _install_external_importers(): """Install importers that require external filesystem access""" global _bootstrap_external import _frozen_importlib_external _bootstrap_external = _frozen_importlib_external _frozen_importlib_external._install(sys.modules[__name__])	38.36 KB	2024-04-17 17:55
📄 _bootstrap_external.py """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 regen-importlib` followed by `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_STR_KEY = 'win', _CASE_INSENSITIVE_PLATFORMS_BYTES_KEY = 'cygwin', 'darwin' _CASE_INSENSITIVE_PLATFORMS = (_CASE_INSENSITIVE_PLATFORMS_BYTES_KEY + _CASE_INSENSITIVE_PLATFORMS_STR_KEY) def _make_relax_case(): if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS): if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS_STR_KEY): key = 'PYTHONCASEOK' else: key = b'PYTHONCASEOK' def _relax_case(): """True if filenames must be checked case-insensitively.""" return key 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. # # 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 3.0b1: 3131 (lexical exception stacking, including POP_EXCEPT #3021) # Python 3.1a1: 3141 (optimize list, set and dict comprehensions: # change LIST_APPEND and SET_ADD, add MAP_ADD #2183) # Python 3.1a1: 3151 (optimize conditional branches: # introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE #4715) # Python 3.2a1: 3160 (add SETUP_WITH #6101) # tag: cpython-32 # Python 3.2a2: 3170 (add DUP_TOP_TWO, remove DUP_TOPX and ROT_FOUR #9225) # tag: cpython-32 # Python 3.2a3 3180 (add DELETE_DEREF #4617) # Python 3.3a1 3190 (__class__ super closure changed) # Python 3.3a1 3200 (PEP 3155 __qualname__ added #13448) # Python 3.3a1 3210 (added size modulo 232 to the pyc header #13645) # Python 3.3a2 3220 (changed PEP 380 implementation #14230) # Python 3.3a4 3230 (revert changes to implicit __class__ closure #14857) # Python 3.4a1 3250 (evaluate positional default arguments before # keyword-only defaults #16967) # Python 3.4a1 3260 (add LOAD_CLASSDEREF; allow locals of class to override # free vars #17853) # Python 3.4a1 3270 (various tweaks to the __class__ closure #12370) # Python 3.4a1 3280 (remove implicit class argument) # Python 3.4a4 3290 (changes to __qualname__ computation #19301) # Python 3.4a4 3300 (more changes to __qualname__ computation #19301) # Python 3.4rc2 3310 (alter __qualname__ computation #20625) # Python 3.5a1 3320 (PEP 465: Matrix multiplication operator #21176) # Python 3.5b1 3330 (PEP 448: Additional Unpacking Generalizations #2292) # Python 3.5b2 3340 (fix dictionary display evaluation order #11205) # Python 3.5b3 3350 (add GET_YIELD_FROM_ITER opcode #24400) # Python 3.5.2 3351 (fix BUILD_MAP_UNPACK_WITH_CALL opcode #27286) # Python 3.6a0 3360 (add FORMAT_VALUE opcode #25483) # Python 3.6a1 3361 (lineno delta of code.co_lnotab becomes signed #26107) # Python 3.6a2 3370 (16 bit wordcode #26647) # Python 3.6a2 3371 (add BUILD_CONST_KEY_MAP opcode #27140) # Python 3.6a2 3372 (MAKE_FUNCTION simplification, remove MAKE_CLOSURE # #27095) # Python 3.6b1 3373 (add BUILD_STRING opcode #27078) # Python 3.6b1 3375 (add SETUP_ANNOTATIONS and STORE_ANNOTATION opcodes # #27985) # Python 3.6b1 3376 (simplify CALL_FUNCTIONs & BUILD_MAP_UNPACK_WITH_CALL #27213) # Python 3.6b1 3377 (set __class__ cell from type.__new__ #23722) # Python 3.6b2 3378 (add BUILD_TUPLE_UNPACK_WITH_CALL #28257) # Python 3.6rc1 3379 (more thorough __class__ validation #23722) # Python 3.7a1 3390 (add LOAD_METHOD and CALL_METHOD opcodes #26110) # Python 3.7a2 3391 (update GET_AITER #31709) # Python 3.7a4 3392 (PEP 552: Deterministic pycs #31650) # Python 3.7b1 3393 (remove STORE_ANNOTATION opcode #32550) # Python 3.7b5 3394 (restored docstring as the first stmt in the body; # this might affected the first line number #32911) # # 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). # # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array # in PC/launcher.c must also be updated. MAGIC_NUMBER = (3394).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 path = _os.fspath(path) 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') path = _os.fspath(path) 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 _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 _classify_pyc(data, name, exc_details): """Perform basic validity checking of a pyc header and return the flags field, which determines how the pyc should be further validated against the source. data* is the contents of the pyc file. (Only the first 16 bytes are required, though.) name is the name of the module being imported. It is used for logging. exc_details is a dictionary passed to ImportError if it raised for improved debugging. ImportError is raised when the magic number is incorrect or when the flags field is invalid. EOFError is raised when the data is found to be truncated. """ magic = data[:4] if magic != MAGIC_NUMBER: message = f'bad magic number in {name!r}: {magic!r}' _bootstrap._verbose_message('{}', message) raise ImportError(message, exc_details) if len(data) < 16: message = f'reached EOF while reading pyc header of {name!r}' _bootstrap._verbose_message('{}', message) raise EOFError(message) flags = _r_long(data[4:8]) # Only the first two flags are defined. if flags & ~0b11: message = f'invalid flags {flags!r} in {name!r}' raise ImportError(message, exc_details) return flags def _validate_timestamp_pyc(data, source_mtime, source_size, name, exc_details): """Validate a pyc against the source last-modified time. data is the contents of the pyc file. (Only the first 16 bytes are required.) source_mtime is the last modified timestamp of the source file. source_size is None or the size of the source file in bytes. name is the name of the module being imported. It is used for logging. exc_details is a dictionary passed to ImportError if it raised for improved debugging. An ImportError is raised if the bytecode is stale. """ if _r_long(data[8:12]) != (source_mtime & 0xFFFFFFFF): message = f'bytecode is stale for {name!r}' _bootstrap._verbose_message('{}', message) raise ImportError(message, exc_details) if (source_size is not None and _r_long(data[12:16]) != (source_size & 0xFFFFFFFF)): raise ImportError(f'bytecode is stale for {name!r}', exc_details) def _validate_hash_pyc(data, source_hash, name, exc_details): """Validate a hash-based pyc by checking the real source hash against the one in the pyc header. data is the contents of the pyc file. (Only the first 16 bytes are required.) source_hash is the importlib.util.source_hash() of the source file. name is the name of the module being imported. It is used for logging. exc_details is a dictionary passed to ImportError if it raised for improved debugging. An ImportError is raised if the bytecode is stale. """ if data[8:16] != source_hash: raise ImportError( f'hash in bytecode doesn\'t match hash of source {name!r}', *exc_details, ) def _compile_bytecode(data, name=None, bytecode_path=None, source_path=None): """Compile bytecode as found in a pyc.""" code = marshal.loads(data) if isinstance(code, _code_type): _bootstrap._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_timestamp_pyc(code, mtime=0, source_size=0): "Produce the data for a timestamp-based pyc." data = bytearray(MAGIC_NUMBER) data.extend(_w_long(0)) data.extend(_w_long(mtime)) data.extend(_w_long(source_size)) data.extend(marshal.dumps(code)) return data def _code_to_hash_pyc(code, source_hash, checked=True): "Produce the data for a hash-based pyc." data = bytearray(MAGIC_NUMBER) flags = 0b1 \| checked << 1 data.extend(_w_long(flags)) assert len(source_hash) == 8 data.extend(source_hash) 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 else: location = _os.fspath(location) # 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='%d.%d' % sys.version_info[:2]) 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): """This module is deprecated.""" 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 OSError when the path cannot be handled. """ raise OSError 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 OSError 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 source_bytes = None source_hash = None hash_based = False check_source = True try: bytecode_path = cache_from_source(source_path) except NotImplementedError: bytecode_path = None else: try: st = self.path_stats(source_path) except OSError: pass else: source_mtime = int(st['mtime']) try: data = self.get_data(bytecode_path) except OSError: pass else: exc_details = { 'name': fullname, 'path': bytecode_path, } try: flags = _classify_pyc(data, fullname, exc_details) bytes_data = memoryview(data)[16:] hash_based = flags & 0b1 != 0 if hash_based: check_source = flags & 0b10 != 0 if (_imp.check_hash_based_pycs != 'never' and (check_source or _imp.check_hash_based_pycs == 'always')): source_bytes = self.get_data(source_path) source_hash = _imp.source_hash( _RAW_MAGIC_NUMBER, source_bytes, ) _validate_hash_pyc(data, source_hash, fullname, exc_details) else: _validate_timestamp_pyc( data, source_mtime, st['size'], fullname, exc_details, ) except (ImportError, EOFError): pass else: _bootstrap._verbose_message('{} matches {}', bytecode_path, source_path) return _compile_bytecode(bytes_data, name=fullname, bytecode_path=bytecode_path, source_path=source_path) if source_bytes is None: source_bytes = self.get_data(source_path) code_object = self.source_to_code(source_bytes, source_path) _bootstrap._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): if hash_based: if source_hash is None: source_hash = _imp.source_hash(source_bytes) data = _code_to_hash_pyc(code_object, source_hash, check_source) else: data = _code_to_timestamp_pyc(code_object, source_mtime, len(source_bytes)) try: self._cache_bytecode(source_path, bytecode_path, data) _bootstrap._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() # ResourceReader ABC API. @_check_name def get_resource_reader(self, module): if self.is_package(module): return self return None def open_resource(self, resource): path = _path_join(_path_split(self.path)[0], resource) return _io.FileIO(path, 'r') def resource_path(self, resource): if not self.is_resource(resource): raise FileNotFoundError path = _path_join(_path_split(self.path)[0], resource) return path def is_resource(self, name): if path_sep in name: return False path = _path_join(_path_split(self.path)[0], name) return _path_isfile(path) def contents(self): return iter(_os.listdir(_path_split(self.path)[0])) 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. _bootstrap._verbose_message('could not create {!r}: {!r}', parent, exc) return try: _write_atomic(path, data, _mode) _bootstrap._verbose_message('created {!r}', path) except OSError as exc: # Same as above: just don't write the bytecode. _bootstrap._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) # Call _classify_pyc to do basic validation of the pyc but ignore the # result. There's no source to check against. exc_details = { 'name': fullname, 'path': path, } _classify_pyc(data, fullname, exc_details) return _compile_bytecode( memoryview(data)[16:], 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) _bootstrap._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) _bootstrap._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 __setitem__(self, index, path): self._path[index] = path 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. _bootstrap._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 name, finder in list(sys.path_importer_cache.items()): if finder is None: del sys.path_importer_cache[name] elif hasattr(finder, 'invalidate_caches'): finder.invalidate_caches() @classmethod def _path_hooks(cls, path): """Search sys.path_hooks for a finder for 'path'.""" 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): """Try to find a spec for 'fullname' on sys.path or 'path'. The search is 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 = None 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 spec for the specified module. Returns the matching spec, or None if not found. """ 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) _bootstrap._verbose_message('trying {}', 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: _bootstrap._verbose_message('possible namespace for {}', 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). thread_module = _bootstrap._builtin_from_name('_thread') 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)]) sys.meta_path.append(PathFinder)	57.63 KB	2024-04-17 17:55
📄 abc.py """Abstract base classes related to import.""" from . import _bootstrap from . import _bootstrap_external from . import machinery try: import _frozen_importlib except ImportError as exc: if exc.name != '_frozen_importlib': raise _frozen_importlib = None try: import _frozen_importlib_external except ImportError as exc: _frozen_importlib_external = _bootstrap_external import abc import warnings def _register(abstract_cls, classes): for cls in classes: abstract_cls.register(cls) if _frozen_importlib is not None: try: frozen_cls = getattr(_frozen_importlib, cls.__name__) except AttributeError: frozen_cls = getattr(_frozen_importlib_external, cls.__name__) abstract_cls.register(frozen_cls) class Finder(metaclass=abc.ABCMeta): """Legacy abstract base class for import finders. It may be subclassed for compatibility with legacy third party reimplementations of the import system. Otherwise, finder implementations should derive from the more specific MetaPathFinder or PathEntryFinder ABCs. Deprecated since Python 3.3 """ @abc.abstractmethod def find_module(self, fullname, path=None): """An abstract method that should find a module. The fullname is a str and the optional path is a str or None. Returns a Loader object or None. """ class MetaPathFinder(Finder): """Abstract base class for import finders on sys.meta_path.""" # We don't define find_spec() here since that would break # hasattr checks we do to support backward compatibility. def find_module(self, fullname, path): """Return a loader for the module. If no module is found, return None. The fullname is a str and the path is a list of strings or None. This method is deprecated since Python 3.4 in favor of finder.find_spec(). If find_spec() exists then backwards-compatible functionality is provided for this method. """ warnings.warn("MetaPathFinder.find_module() is deprecated since Python " "3.4 in favor of MetaPathFinder.find_spec() " "(available since 3.4)", DeprecationWarning, stacklevel=2) if not hasattr(self, 'find_spec'): return None found = self.find_spec(fullname, path) return found.loader if found is not None else None def invalidate_caches(self): """An optional method for clearing the finder's cache, if any. This method is used by importlib.invalidate_caches(). """ _register(MetaPathFinder, machinery.BuiltinImporter, machinery.FrozenImporter, machinery.PathFinder, machinery.WindowsRegistryFinder) class PathEntryFinder(Finder): """Abstract base class for path entry finders used by PathFinder.""" # We don't define find_spec() here since that would break # hasattr checks we do to support backward compatibility. def find_loader(self, fullname): """Return (loader, namespace portion) for the path entry. The fullname is a str. The namespace portion is a sequence of path entries contributing to part of a namespace package. The sequence may be empty. If loader is not None, the portion will be ignored. The portion will be discarded if another path entry finder locates the module as a normal module or package. This method is deprecated since Python 3.4 in favor of finder.find_spec(). If find_spec() is provided than backwards-compatible functionality is provided. """ warnings.warn("PathEntryFinder.find_loader() is deprecated since Python " "3.4 in favor of PathEntryFinder.find_spec() " "(available since 3.4)", DeprecationWarning, stacklevel=2) if not hasattr(self, 'find_spec'): return None, [] found = self.find_spec(fullname) if found is not None: if not found.submodule_search_locations: portions = [] else: portions = found.submodule_search_locations return found.loader, portions else: return None, [] find_module = _bootstrap_external._find_module_shim def invalidate_caches(self): """An optional method for clearing the finder's cache, if any. This method is used by PathFinder.invalidate_caches(). """ _register(PathEntryFinder, machinery.FileFinder) class Loader(metaclass=abc.ABCMeta): """Abstract base class for import loaders.""" def create_module(self, spec): """Return a module to initialize and into which to load. This method should raise ImportError if anything prevents it from creating a new module. It may return None to indicate that the spec should create the new module. """ # By default, defer to default semantics for the new module. return None # We don't define exec_module() here since that would break # hasattr checks we do to support backward compatibility. def load_module(self, fullname): """Return the loaded module. The module must be added to sys.modules and have import-related attributes set properly. The fullname is a str. ImportError is raised on failure. This method is deprecated in favor of loader.exec_module(). If exec_module() exists then it is used to provide a backwards-compatible functionality for this method. """ if not hasattr(self, 'exec_module'): raise ImportError return _bootstrap._load_module_shim(self, fullname) def module_repr(self, module): """Return a module's repr. Used by the module type when the method does not raise NotImplementedError. This method is deprecated. """ # The exception will cause ModuleType.__repr__ to ignore this method. raise NotImplementedError class ResourceLoader(Loader): """Abstract base class for loaders which can return data from their back-end storage. This ABC represents one of the optional protocols specified by PEP 302. """ @abc.abstractmethod def get_data(self, path): """Abstract method which when implemented should return the bytes for the specified path. The path must be a str.""" raise OSError class InspectLoader(Loader): """Abstract base class for loaders which support inspection about the modules they can load. This ABC represents one of the optional protocols specified by PEP 302. """ def is_package(self, fullname): """Optional method which when implemented should return whether the module is a package. The fullname is a str. Returns a bool. Raises ImportError if the module cannot be found. """ raise ImportError def get_code(self, fullname): """Method which returns the code object for the module. The fullname is a str. Returns a types.CodeType if possible, else returns None if a code object does not make sense (e.g. built-in module). Raises ImportError if the module cannot be found. """ source = self.get_source(fullname) if source is None: return None return self.source_to_code(source) @abc.abstractmethod def get_source(self, fullname): """Abstract method which should return the source code for the module. The fullname is a str. Returns a str. Raises ImportError if the module cannot be found. """ raise ImportError @staticmethod def source_to_code(data, path='<string>'): """Compile 'data' into a code object. The 'data' argument can be anything that compile() can handle. The'path' argument should be where the data was retrieved (when applicable).""" return compile(data, path, 'exec', dont_inherit=True) exec_module = _bootstrap_external._LoaderBasics.exec_module load_module = _bootstrap_external._LoaderBasics.load_module _register(InspectLoader, machinery.BuiltinImporter, machinery.FrozenImporter) class ExecutionLoader(InspectLoader): """Abstract base class for loaders that wish to support the execution of modules as scripts. This ABC represents one of the optional protocols specified in PEP 302. """ @abc.abstractmethod def get_filename(self, fullname): """Abstract method which should return the value that __file__ is to be set to. Raises ImportError if the module cannot be found. """ raise ImportError def get_code(self, fullname): """Method to return the code object for fullname. Should return None if not applicable (e.g. built-in module). Raise ImportError if the module cannot be found. """ source = self.get_source(fullname) if source is None: return None try: path = self.get_filename(fullname) except ImportError: return self.source_to_code(source) else: return self.source_to_code(source, path) _register(ExecutionLoader, machinery.ExtensionFileLoader) class FileLoader(_bootstrap_external.FileLoader, ResourceLoader, ExecutionLoader): """Abstract base class partially implementing the ResourceLoader and ExecutionLoader ABCs.""" _register(FileLoader, machinery.SourceFileLoader, machinery.SourcelessFileLoader) class SourceLoader(_bootstrap_external.SourceLoader, ResourceLoader, ExecutionLoader): """Abstract base class for loading source code (and optionally any corresponding bytecode). To support loading from source code, the abstractmethods inherited from ResourceLoader and ExecutionLoader need to be implemented. To also support loading from bytecode, the optional methods specified directly by this ABC is required. Inherited abstractmethods not implemented in this ABC: ResourceLoader.get_data * ExecutionLoader.get_filename """ def path_mtime(self, path): """Return the (int) modification time for the path (str).""" if self.path_stats.__func__ is SourceLoader.path_stats: raise OSError return int(self.path_stats(path)['mtime']) def path_stats(self, path): """Return a metadata dict for the source pointed 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. """ if self.path_mtime.__func__ is SourceLoader.path_mtime: raise OSError return {'mtime': self.path_mtime(path)} def set_data(self, path, data): """Write the bytes to the path (if possible). Accepts a str path and data as bytes. Any needed intermediary directories are to be created. If for some reason the file cannot be written because of permissions, fail silently. """ _register(SourceLoader, machinery.SourceFileLoader) class ResourceReader(metaclass=abc.ABCMeta): """Abstract base class to provide resource-reading support. Loaders that support resource reading are expected to implement the ``get_resource_reader(fullname)`` method and have it either return None or an object compatible with this ABC. """ @abc.abstractmethod def open_resource(self, resource): """Return an opened, file-like object for binary reading. The 'resource' argument is expected to represent only a file name and thus not contain any subdirectory components. If the resource cannot be found, FileNotFoundError is raised. """ raise FileNotFoundError @abc.abstractmethod def resource_path(self, resource): """Return the file system path to the specified resource. The 'resource' argument is expected to represent only a file name and thus not contain any subdirectory components. If the resource does not exist on the file system, raise FileNotFoundError. """ raise FileNotFoundError @abc.abstractmethod def is_resource(self, name): """Return True if the named 'name' is consider a resource.""" raise FileNotFoundError @abc.abstractmethod def contents(self): """Return an iterable of strings over the contents of the package.""" return [] _register(ResourceReader, machinery.SourceFileLoader)	12.57 KB	2024-04-17 17:55
📄 machinery.py """The machinery of importlib: finders, loaders, hooks, etc.""" import _imp from ._bootstrap import ModuleSpec from ._bootstrap import BuiltinImporter from ._bootstrap import FrozenImporter from ._bootstrap_external import (SOURCE_SUFFIXES, DEBUG_BYTECODE_SUFFIXES, OPTIMIZED_BYTECODE_SUFFIXES, BYTECODE_SUFFIXES, EXTENSION_SUFFIXES) from ._bootstrap_external import WindowsRegistryFinder from ._bootstrap_external import PathFinder from ._bootstrap_external import FileFinder from ._bootstrap_external import SourceFileLoader from ._bootstrap_external import SourcelessFileLoader from ._bootstrap_external import ExtensionFileLoader def all_suffixes(): """Returns a list of all recognized module suffixes for this process""" return SOURCE_SUFFIXES + BYTECODE_SUFFIXES + EXTENSION_SUFFIXES	844 B	2024-04-17 17:55
📄 resources.py import os import tempfile from . import abc as resources_abc from contextlib import contextmanager, suppress from importlib import import_module from importlib.abc import ResourceLoader from io import BytesIO, TextIOWrapper from pathlib import Path from types import ModuleType from typing import Iterable, Iterator, Optional, Set, Union # noqa: F401 from typing import cast from typing.io import BinaryIO, TextIO from zipimport import ZipImportError __all__ = [ 'Package', 'Resource', 'contents', 'is_resource', 'open_binary', 'open_text', 'path', 'read_binary', 'read_text', ] Package = Union[str, ModuleType] Resource = Union[str, os.PathLike] def _get_package(package) -> ModuleType: """Take a package name or module object and return the module. If a name, the module is imported. If the passed or imported module object is not a package, raise an exception. """ if hasattr(package, '__spec__'): if package.__spec__.submodule_search_locations is None: raise TypeError('{!r} is not a package'.format( package.__spec__.name)) else: return package else: module = import_module(package) if module.__spec__.submodule_search_locations is None: raise TypeError('{!r} is not a package'.format(package)) else: return module def _normalize_path(path) -> str: """Normalize a path by ensuring it is a string. If the resulting string contains path separators, an exception is raised. """ parent, file_name = os.path.split(path) if parent: raise ValueError('{!r} must be only a file name'.format(path)) else: return file_name def _get_resource_reader( package: ModuleType) -> Optional[resources_abc.ResourceReader]: # Return the package's loader if it's a ResourceReader. We can't use # a issubclass() check here because apparently abc.'s __subclasscheck__() # hook wants to create a weak reference to the object, but # zipimport.zipimporter does not support weak references, resulting in a # TypeError. That seems terrible. spec = package.__spec__ if hasattr(spec.loader, 'get_resource_reader'): return cast(resources_abc.ResourceReader, spec.loader.get_resource_reader(spec.name)) return None def _check_location(package): if package.__spec__.origin is None or not package.__spec__.has_location: raise FileNotFoundError(f'Package has no location {package!r}') def open_binary(package: Package, resource: Resource) -> BinaryIO: """Return a file-like object opened for binary reading of the resource.""" resource = _normalize_path(resource) package = _get_package(package) reader = _get_resource_reader(package) if reader is not None: return reader.open_resource(resource) _check_location(package) absolute_package_path = os.path.abspath(package.__spec__.origin) package_path = os.path.dirname(absolute_package_path) full_path = os.path.join(package_path, resource) try: return open(full_path, mode='rb') except OSError: # Just assume the loader is a resource loader; all the relevant # importlib.machinery loaders are and an AttributeError for # get_data() will make it clear what is needed from the loader. loader = cast(ResourceLoader, package.__spec__.loader) data = None if hasattr(package.__spec__.loader, 'get_data'): with suppress(OSError): data = loader.get_data(full_path) if data is None: package_name = package.__spec__.name message = '{!r} resource not found in {!r}'.format( resource, package_name) raise FileNotFoundError(message) else: return BytesIO(data) def open_text(package: Package, resource: Resource, encoding: str = 'utf-8', errors: str = 'strict') -> TextIO: """Return a file-like object opened for text reading of the resource.""" resource = _normalize_path(resource) package = _get_package(package) reader = _get_resource_reader(package) if reader is not None: return TextIOWrapper(reader.open_resource(resource), encoding, errors) _check_location(package) absolute_package_path = os.path.abspath(package.__spec__.origin) package_path = os.path.dirname(absolute_package_path) full_path = os.path.join(package_path, resource) try: return open(full_path, mode='r', encoding=encoding, errors=errors) except OSError: # Just assume the loader is a resource loader; all the relevant # importlib.machinery loaders are and an AttributeError for # get_data() will make it clear what is needed from the loader. loader = cast(ResourceLoader, package.__spec__.loader) data = None if hasattr(package.__spec__.loader, 'get_data'): with suppress(OSError): data = loader.get_data(full_path) if data is None: package_name = package.__spec__.name message = '{!r} resource not found in {!r}'.format( resource, package_name) raise FileNotFoundError(message) else: return TextIOWrapper(BytesIO(data), encoding, errors) def read_binary(package: Package, resource: Resource) -> bytes: """Return the binary contents of the resource.""" resource = _normalize_path(resource) package = _get_package(package) with open_binary(package, resource) as fp: return fp.read() def read_text(package: Package, resource: Resource, encoding: str = 'utf-8', errors: str = 'strict') -> str: """Return the decoded string of the resource. The decoding-related arguments have the same semantics as those of bytes.decode(). """ resource = _normalize_path(resource) package = _get_package(package) with open_text(package, resource, encoding, errors) as fp: return fp.read() @contextmanager def path(package: Package, resource: Resource) -> Iterator[Path]: """A context manager providing a file path object to the resource. If the resource does not already exist on its own on the file system, a temporary file will be created. If the file was created, the file will be deleted upon exiting the context manager (no exception is raised if the file was deleted prior to the context manager exiting). """ resource = _normalize_path(resource) package = _get_package(package) reader = _get_resource_reader(package) if reader is not None: try: yield Path(reader.resource_path(resource)) return except FileNotFoundError: pass else: _check_location(package) # Fall-through for both the lack of resource_path() and if # resource_path() raises FileNotFoundError. package_directory = Path(package.__spec__.origin).parent file_path = package_directory / resource if file_path.exists(): yield file_path else: with open_binary(package, resource) as fp: data = fp.read() # Not using tempfile.NamedTemporaryFile as it leads to deeper 'try' # blocks due to the need to close the temporary file to work on # Windows properly. fd, raw_path = tempfile.mkstemp() try: os.write(fd, data) os.close(fd) yield Path(raw_path) finally: try: os.remove(raw_path) except FileNotFoundError: pass def is_resource(package: Package, name: str) -> bool: """True if 'name' is a resource inside 'package'. Directories are not resources. """ package = _get_package(package) _normalize_path(name) reader = _get_resource_reader(package) if reader is not None: return reader.is_resource(name) try: package_contents = set(contents(package)) except (NotADirectoryError, FileNotFoundError): return False if name not in package_contents: return False # Just because the given file_name lives as an entry in the package's # contents doesn't necessarily mean it's a resource. Directories are not # resources, so let's try to find out if it's a directory or not. path = Path(package.__spec__.origin).parent / name return path.is_file() def contents(package: Package) -> Iterable[str]: """Return an iterable of entries in 'package'. Note that not all entries are resources. Specifically, directories are not considered resources. Use `is_resource()` on each entry returned here to check if it is a resource or not. """ package = _get_package(package) reader = _get_resource_reader(package) if reader is not None: return reader.contents() # Is the package a namespace package? By definition, namespace packages # cannot have resources. We could use _check_location() and catch the # exception, but that's extra work, so just inline the check. elif package.__spec__.origin is None or not package.__spec__.has_location: return () else: package_directory = Path(package.__spec__.origin).parent return os.listdir(package_directory) # Private implementation of ResourceReader and get_resource_reader() called # from zipimport.c. Don't use these directly! We're implementing these in # Python because 1) it's easier, 2) zipimport may get rewritten in Python # itself at some point, so doing this all in C would difficult and a waste of # effort. class _ZipImportResourceReader(resources_abc.ResourceReader): """Private class used to support ZipImport.get_resource_reader(). This class is allowed to reference all the innards and private parts of the zipimporter. """ def __init__(self, zipimporter, fullname): self.zipimporter = zipimporter self.fullname = fullname def open_resource(self, resource): fullname_as_path = self.fullname.replace('.', '/') path = f'{fullname_as_path}/{resource}' try: return BytesIO(self.zipimporter.get_data(path)) except OSError: raise FileNotFoundError(path) def resource_path(self, resource): # All resources are in the zip file, so there is no path to the file. # Raising FileNotFoundError tells the higher level API to extract the # binary data and create a temporary file. raise FileNotFoundError def is_resource(self, name): # Maybe we could do better, but if we can get the data, it's a # resource. Otherwise it isn't. fullname_as_path = self.fullname.replace('.', '/') path = f'{fullname_as_path}/{name}' try: self.zipimporter.get_data(path) except OSError: return False return True def contents(self): # This is a bit convoluted, because fullname will be a module path, # but _files is a list of file names relative to the top of the # archive's namespace. We want to compare file paths to find all the # names of things inside the module represented by fullname. So we # turn the module path of fullname into a file path relative to the # top of the archive, and then we iterate through _files looking for # names inside that "directory". fullname_path = Path(self.zipimporter.get_filename(self.fullname)) relative_path = fullname_path.relative_to(self.zipimporter.archive) # Don't forget that fullname names a package, so its path will include # __init__.py, which we want to ignore. assert relative_path.name == '__init__.py' package_path = relative_path.parent subdirs_seen = set() for filename in self.zipimporter._files: try: relative = Path(filename).relative_to(package_path) except ValueError: continue # If the path of the file (which is relative to the top of the zip # namespace), relative to the package given when the resource # reader was created, has a parent, then it's a name in a # subdirectory and thus we skip it. parent_name = relative.parent.name if len(parent_name) == 0: yield relative.name elif parent_name not in subdirs_seen: subdirs_seen.add(parent_name) yield parent_name # Called from zipimport.c def _zipimport_get_resource_reader(zipimporter, fullname): try: if not zipimporter.is_package(fullname): return None except ZipImportError: return None return _ZipImportResourceReader(zipimporter, fullname)	12.66 KB	2024-04-17 17:55
📄 util.py """Utility code for constructing importers, etc.""" from . import abc from ._bootstrap import module_from_spec from ._bootstrap import _resolve_name from ._bootstrap import spec_from_loader from ._bootstrap import _find_spec from ._bootstrap_external import MAGIC_NUMBER from ._bootstrap_external import _RAW_MAGIC_NUMBER from ._bootstrap_external import cache_from_source from ._bootstrap_external import decode_source from ._bootstrap_external import source_from_cache from ._bootstrap_external import spec_from_file_location from contextlib import contextmanager import _imp import functools import sys import types import warnings def source_hash(source_bytes): "Return the hash of source_bytes as used in hash-based pyc files." return _imp.source_hash(_RAW_MAGIC_NUMBER, source_bytes) def resolve_name(name, package): """Resolve a relative module name to an absolute one.""" if not name.startswith('.'): return name elif not package: raise ValueError(f'no package specified for {repr(name)} ' '(required for relative module names)') level = 0 for character in name: if character != '.': break level += 1 return _resolve_name(name[level:], package, level) def _find_spec_from_path(name, path=None): """Return the spec for the specified module. First, sys.modules is checked to see if the module was already imported. If so, then sys.modules[name].__spec__ is returned. If that happens to be set to None, then ValueError is raised. If the module is not in sys.modules, then sys.meta_path is searched for a suitable spec with the value of 'path' given to the finders. None is returned if no spec could be found. Dotted names do not have their parent packages implicitly imported. You will most likely need to explicitly import all parent packages in the proper order for a submodule to get the correct spec. """ if name not in sys.modules: return _find_spec(name, path) else: module = sys.modules[name] if module is None: return None try: spec = module.__spec__ except AttributeError: raise ValueError('{}.__spec__ is not set'.format(name)) from None else: if spec is None: raise ValueError('{}.__spec__ is None'.format(name)) return spec def find_spec(name, package=None): """Return the spec for the specified module. First, sys.modules is checked to see if the module was already imported. If so, then sys.modules[name].__spec__ is returned. If that happens to be set to None, then ValueError is raised. If the module is not in sys.modules, then sys.meta_path is searched for a suitable spec with the value of 'path' given to the finders. None is returned if no spec could be found. If the name is for submodule (contains a dot), the parent module is automatically imported. The name and package arguments work the same as importlib.import_module(). In other words, relative module names (with leading dots) work. """ fullname = resolve_name(name, package) if name.startswith('.') else name if fullname not in sys.modules: parent_name = fullname.rpartition('.')[0] if parent_name: parent = __import__(parent_name, fromlist=['__path__']) try: parent_path = parent.__path__ except AttributeError as e: raise ModuleNotFoundError( f"__path__ attribute not found on {parent_name!r} " f"while trying to find {fullname!r}", name=fullname) from e else: parent_path = None return _find_spec(fullname, parent_path) else: module = sys.modules[fullname] if module is None: return None try: spec = module.__spec__ except AttributeError: raise ValueError('{}.__spec__ is not set'.format(name)) from None else: if spec is None: raise ValueError('{}.__spec__ is None'.format(name)) return spec @contextmanager def _module_to_load(name): is_reload = name in sys.modules module = sys.modules.get(name) if not is_reload: # This must be done before open() is called as the 'io' module # implicitly imports 'locale' and would otherwise trigger an # infinite loop. module = type(sys)(name) # This must be done before putting the module in sys.modules # (otherwise an optimization shortcut in import.c becomes wrong) module.__initializing__ = True sys.modules[name] = module try: yield module except Exception: if not is_reload: try: del sys.modules[name] except KeyError: pass finally: module.__initializing__ = False def set_package(fxn): """Set __package__ on the returned module. This function is deprecated. """ @functools.wraps(fxn) def set_package_wrapper(args, kwargs): warnings.warn('The import system now takes care of this automatically.', DeprecationWarning, stacklevel=2) module = fxn(args, *kwargs) if getattr(module, '__package__', None) is None: module.__package__ = module.__name__ if not hasattr(module, '__path__'): module.__package__ = module.__package__.rpartition('.')[0] return module return set_package_wrapper def set_loader(fxn): """Set __loader__ on the returned module. This function is deprecated. """ @functools.wraps(fxn) def set_loader_wrapper(self, args, *kwargs): warnings.warn('The import system now takes care of this automatically.', DeprecationWarning, stacklevel=2) module = fxn(self, args, *kwargs) if getattr(module, '__loader__', None) is None: module.__loader__ = self return module return set_loader_wrapper def module_for_loader(fxn): """Decorator to handle selecting the proper module for loaders. The decorated function is passed the module to use instead of the module name. The module passed in to the function is either from sys.modules if it already exists or is a new module. If the module is new, then __name__ is set the first argument to the method, __loader__ is set to self, and __package__ is set accordingly (if self.is_package() is defined) will be set before it is passed to the decorated function (if self.is_package() does not work for the module it will be set post-load). If an exception is raised and the decorator created the module it is subsequently removed from sys.modules. The decorator assumes that the decorated function takes the module name as the second argument. """ warnings.warn('The import system now takes care of this automatically.', DeprecationWarning, stacklevel=2) @functools.wraps(fxn) def module_for_loader_wrapper(self, fullname, args, *kwargs): with _module_to_load(fullname) as module: module.__loader__ = self try: is_package = self.is_package(fullname) except (ImportError, AttributeError): pass else: if is_package: module.__package__ = fullname else: module.__package__ = fullname.rpartition('.')[0] # If __package__ was not set above, __import__() will do it later. return fxn(self, module, args, *kwargs) return module_for_loader_wrapper class _LazyModule(types.ModuleType): """A subclass of the module type which triggers loading upon attribute access.""" def __getattribute__(self, attr): """Trigger the load of the module and return the attribute.""" # All module metadata must be garnered from __spec__ in order to avoid # using mutated values. # Stop triggering this method. self.__class__ = types.ModuleType # Get the original name to make sure no object substitution occurred # in sys.modules. original_name = self.__spec__.name # Figure out exactly what attributes were mutated between the creation # of the module and now. attrs_then = self.__spec__.loader_state['__dict__'] original_type = self.__spec__.loader_state['__class__'] attrs_now = self.__dict__ attrs_updated = {} for key, value in attrs_now.items(): # Code that set the attribute may have kept a reference to the # assigned object, making identity more important than equality. if key not in attrs_then: attrs_updated[key] = value elif id(attrs_now[key]) != id(attrs_then[key]): attrs_updated[key] = value self.__spec__.loader.exec_module(self) # If exec_module() was used directly there is no guarantee the module # object was put into sys.modules. if original_name in sys.modules: if id(self) != id(sys.modules[original_name]): raise ValueError(f"module object for {original_name!r} " "substituted in sys.modules during a lazy " "load") # Update after loading since that's what would happen in an eager # loading situation. self.__dict__.update(attrs_updated) return getattr(self, attr) def __delattr__(self, attr): """Trigger the load and then perform the deletion.""" # To trigger the load and raise an exception if the attribute # doesn't exist. self.__getattribute__(attr) delattr(self, attr) class LazyLoader(abc.Loader): """A loader that creates a module which defers loading until attribute access.""" @staticmethod def __check_eager_loader(loader): if not hasattr(loader, 'exec_module'): raise TypeError('loader must define exec_module()') @classmethod def factory(cls, loader): """Construct a callable which returns the eager loader made lazy.""" cls.__check_eager_loader(loader) return lambda args, *kwargs: cls(loader(args, **kwargs)) def __init__(self, loader): self.__check_eager_loader(loader) self.loader = loader def create_module(self, spec): return self.loader.create_module(spec) def exec_module(self, module): """Make the module load lazily.""" module.__spec__.loader = self.loader module.__loader__ = self.loader # Don't need to worry about deep-copying as trying to set an attribute # on an object would have triggered the load, # e.g. ``module.__spec__.loader = None`` would trigger a load from # trying to access module.__spec__. loader_state = {} loader_state['__dict__'] = module.__dict__.copy() loader_state['__class__'] = module.__class__ module.__spec__.loader_state = loader_state module.__class__ = _LazyModule	11.05 KB	2024-04-17 17:55

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