Lib/importlib/abc.py - platform/external/python/cpython3 - Gitiles

 """Abstract base classes related to import."""
 from . import _bootstrap
 from . import machinery
 try:
     import _frozen_importlib
 except ImportError as exc:
     if exc.name != '_frozen_importlib':
         raise
     _frozen_importlib = None
 import abc


 def _register(abstract_cls, *classes):
     for cls in classes:
         abstract_cls.register(cls)
         if _frozen_importlib is not None:
             frozen_cls = getattr(_frozen_importlib, 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.
     """

     @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.

     # XXX Deprecate
     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.

         """
         return 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.

     # XXX Deprecate.
     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.

         """
         return None, []

     # XXX Deprecate.
     find_module = _bootstrap._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.

         create_module() is optional.

         """
         # By default, defer to _SpecMethods.create() 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.

     # XXX Deprecate.
     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.

         """
         raise ImportError

     # XXX Deprecate.
     def module_repr(self, module):
         """Return a module's repr.

         Used by the module type when the method does not raise
         NotImplementedError.

         """
         # 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 IOError


 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

     def source_to_code(self, 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._LoaderBasics.exec_module
     load_module = _bootstrap._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.FileLoader, ResourceLoader, ExecutionLoader):

     """Abstract base class partially implementing the ResourceLoader and
     ExecutionLoader ABCs."""

 _register(FileLoader, machinery.SourceFileLoader,
             machinery.SourcelessFileLoader)


 class SourceLoader(_bootstrap.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 IOError
         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 IOError
         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)
	"""Abstract base classes related to import."""
	from . import _bootstrap
	from . import machinery
	try:
	import _frozen_importlib
	except ImportError as exc:
	if exc.name != '_frozen_importlib':
	raise
	_frozen_importlib = None
	import abc


	def _register(abstract_cls, *classes):
	for cls in classes:
	abstract_cls.register(cls)
	if _frozen_importlib is not None:
	frozen_cls = getattr(_frozen_importlib, 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.
	"""

	@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.

	# XXX Deprecate
	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.

	"""
	return 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.

	# XXX Deprecate.
	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.

	"""
	return None, []

	# XXX Deprecate.
	find_module = _bootstrap._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.

	create_module() is optional.

	"""
	# By default, defer to _SpecMethods.create() 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.

	# XXX Deprecate.
	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.

	"""
	raise ImportError

	# XXX Deprecate.
	def module_repr(self, module):
	"""Return a module's repr.

	Used by the module type when the method does not raise
	NotImplementedError.

	"""
	# 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 IOError


	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

	def source_to_code(self, 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._LoaderBasics.exec_module
	load_module = _bootstrap._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.FileLoader, ResourceLoader, ExecutionLoader):

	"""Abstract base class partially implementing the ResourceLoader and
	ExecutionLoader ABCs."""

	_register(FileLoader, machinery.SourceFileLoader,
	machinery.SourcelessFileLoader)


	class SourceLoader(_bootstrap.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 IOError
	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 IOError
	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)