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author | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:24:06 +0300 |
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committer | nkozlovskiy <nmk@ydb.tech> | 2023-09-29 12:41:34 +0300 |
commit | e0e3e1717e3d33762ce61950504f9637a6e669ed (patch) | |
tree | bca3ff6939b10ed60c3d5c12439963a1146b9711 /contrib/tools/python3/src/Lib/importlib/util.py | |
parent | 38f2c5852db84c7b4d83adfcb009eb61541d1ccd (diff) | |
download | ydb-e0e3e1717e3d33762ce61950504f9637a6e669ed.tar.gz |
add ydb deps
Diffstat (limited to 'contrib/tools/python3/src/Lib/importlib/util.py')
-rw-r--r-- | contrib/tools/python3/src/Lib/importlib/util.py | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/contrib/tools/python3/src/Lib/importlib/util.py b/contrib/tools/python3/src/Lib/importlib/util.py new file mode 100644 index 0000000000..8623c89840 --- /dev/null +++ b/contrib/tools/python3/src/Lib/importlib/util.py @@ -0,0 +1,302 @@ +"""Utility code for constructing importers, etc.""" +from ._abc import Loader +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; ' + 'this decorator is slated for removal in Python 3.12', + 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; ' + 'this decorator is slated for removal in Python 3.12', + 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; ' + 'this decorator is slated for removal in Python 3.12', + 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__'] + 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(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 |