"""Abstract base classes related to import.""" 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: _frozen_importlib_external = _bootstrap_external from ._abc import Loader import abc import warnings from typing import BinaryIO, Iterable, Text from typing import Protocol, runtime_checkable 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 """ def __init__(self): warnings.warn("the Finder ABC is deprecated and " "slated for removal in Python 3.12; use MetaPathFinder " "or PathEntryFinder instead", DeprecationWarning) @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. """ warnings.warn("importlib.abc.Finder along with its find_module() " "method are deprecated and " "slated for removal in Python 3.12; use " "MetaPathFinder.find_spec() or " "PathEntryFinder.find_spec() instead", DeprecationWarning) class MetaPathFinder(metaclass=abc.ABCMeta): """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() and is " "slated for removal in Python 3.12", 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(metaclass=abc.ABCMeta): """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 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=''): """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 for loaders to provide resource reading support.""" @abc.abstractmethod def open_resource(self, resource: Text) -> BinaryIO: """Return an opened, file-like object for binary reading. The 'resource' argument is expected to represent only a file name. If the resource cannot be found, FileNotFoundError is raised. """ # This deliberately raises FileNotFoundError instead of # NotImplementedError so that if this method is accidentally called, # it'll still do the right thing. raise FileNotFoundError @abc.abstractmethod def resource_path(self, resource: Text) -> Text: """Return the file system path to the specified resource. The 'resource' argument is expected to represent only a file name. If the resource does not exist on the file system, raise FileNotFoundError. """ # This deliberately raises FileNotFoundError instead of # NotImplementedError so that if this method is accidentally called, # it'll still do the right thing. raise FileNotFoundError @abc.abstractmethod def is_resource(self, path: Text) -> bool: """Return True if the named 'path' is a resource. Files are resources, directories are not. """ raise FileNotFoundError @abc.abstractmethod def contents(self) -> Iterable[str]: """Return an iterable of entries in `package`.""" raise FileNotFoundError @runtime_checkable class Traversable(Protocol): """ An object with a subset of pathlib.Path methods suitable for traversing directories and opening files. """ @abc.abstractmethod def iterdir(self): """ Yield Traversable objects in self """ def read_bytes(self): """ Read contents of self as bytes """ with self.open('rb') as strm: return strm.read() def read_text(self, encoding=None): """ Read contents of self as text """ with self.open(encoding=encoding) as strm: return strm.read() @abc.abstractmethod def is_dir(self) -> bool: """ Return True if self is a dir """ @abc.abstractmethod def is_file(self) -> bool: """ Return True if self is a file """ @abc.abstractmethod def joinpath(self, child): """ Return Traversable child in self """ def __truediv__(self, child): """ Return Traversable child in self """ return self.joinpath(child) @abc.abstractmethod def open(self, mode='r', *args, **kwargs): """ mode may be 'r' or 'rb' to open as text or binary. Return a handle suitable for reading (same as pathlib.Path.open). When opening as text, accepts encoding parameters such as those accepted by io.TextIOWrapper. """ @abc.abstractproperty def name(self) -> str: """ The base name of this object without any parent references. """ class TraversableResources(ResourceReader): """ The required interface for providing traversable resources. """ @abc.abstractmethod def files(self): """Return a Traversable object for the loaded package.""" def open_resource(self, resource): return self.files().joinpath(resource).open('rb') def resource_path(self, resource): raise FileNotFoundError(resource) def is_resource(self, path): return self.files().joinpath(path).is_file() def contents(self): return (item.name for item in self.files().iterdir())