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Diffstat (limited to 'Lib/importlib/util.py')
| -rw-r--r-- | Lib/importlib/util.py | 300 |
1 files changed, 0 insertions, 300 deletions
diff --git a/Lib/importlib/util.py b/Lib/importlib/util.py deleted file mode 100644 index 269a6fa..0000000 --- a/Lib/importlib/util.py +++ /dev/null @@ -1,300 +0,0 @@ -"""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 ImportError(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 |