class _SpecMethods:
def __init__(self, spec):
self.spec = spec
def module_repr(self):
"""Return the repr to use for the module."""
# We mostly replicate _module_repr() using the spec attributes.
spec = self.spec
name = '?' if spec.name is None else spec.name
if spec.origin is None:
if spec.loader is None:
return ''.format(name)
else:
return ''.format(name, spec.loader)
else:
if spec.has_location:
return ''.format(name, spec.origin)
else:
return ''.format(spec.name, spec.origin)
def init_module_attrs(self, module, *, _override=False, _force_name=True):
"""Set the module's attributes.
All missing import-related module attributes will be set. Here
is how the spec attributes map onto the module:
spec.name -> module.__name__
spec.loader -> module.__loader__
spec.parent -> module.__package__
spec -> module.__spec__
Optional:
spec.origin -> module.__file__ (if spec.set_fileattr is true)
spec.cached -> module.__cached__ (if __file__ also set)
spec.submodule_search_locations -> module.__path__ (if set)
"""
spec = self.spec
# The passed in module may be not support attribute assignment,
# in which case we simply don't set the attributes.
# __name__
if (_override or _force_name 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:
loader = _NamespaceLoader.__new__(_NamespaceLoader)
loader._path = spec.submodule_search_locations
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
if spec.has_location:
# __file__
if _override or getattr(module, '__file__', None) is None:
try:
module.__file__ = spec.origin
except AttributeError:
pass
# __cached__
if _override or getattr(module, '__cached__', None) is None:
if spec.cached is not None:
try:
module.__cached__ = spec.cached
except AttributeError:
pass
def create(self):
"""Return a new module to be loaded.
The import-related module attributes are also set with the
appropriate values from the spec.
"""
spec = self.spec
# Typically loaders will not implement create_module().
if hasattr(spec.loader, 'create_module'):
# If create_module() returns `None` it means the default
# module creation should be used.
module = spec.loader.create_module(spec)
else:
module = None
if module is None:
# This must be done before open() is ever called as the 'io'
# module implicitly imports 'locale' and would otherwise
# trigger an infinite loop.
module = _new_module(spec.name)
self.init_module_attrs(module)
return module
def _exec(self, module):
"""Do everything necessary to execute the module.
The namespace of `module` is used as the target of execution.
This method uses the loader's `exec_module()` method.
"""
self.spec.loader.exec_module(module)
# Used by importlib.reload() and _load_module_shim().
def exec(self, module):
"""Execute the spec in an existing module's namespace."""
name = self.spec.name
_imp.acquire_lock()
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 self.spec.loader is None:
if self.spec.submodule_search_locations is None:
raise ImportError('missing loader', name=self.spec.name)
# namespace package
self.init_module_attrs(module, _override=True)
return module
self.init_module_attrs(module, _override=True)
if not hasattr(self.spec.loader, 'exec_module'):
# (issue19713) Once BuiltinImporter and ExtensionFileLoader
# have exec_module() implemented, we can add a deprecation
# warning here.
self.spec.loader.load_module(name)
else:
self._exec(module)
return sys.modules[name]
def _load_backward_compatible(self):
# (issue19713) Once BuiltinImporter and ExtensionFileLoader
# have exec_module() implemented, we can add a deprecation
# warning here.
spec = self.spec
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(self):
# A helper for direct use by the import system.
if self.spec.loader is not None:
# not a namespace package
if not hasattr(self.spec.loader, 'exec_module'):
return self._load_backward_compatible()
module = self.create()
with _installed_safely(module):
if self.spec.loader is None:
if self.spec.submodule_search_locations is None:
raise ImportError('missing loader', name=self.spec.name)
# A namespace package so do nothing.
else:
self._exec(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[self.spec.name]
# A method used during testing of _load_unlocked() and by
# _load_module_shim().
def load(self):
"""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.
"""
_imp.acquire_lock()
with _ModuleLockManager(self.spec.name):
return self._load_unlocked()
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
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 ''.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
@_requires_builtin
def load_module(cls, fullname):
"""Load a built-in module."""
# Once an exec_module() implementation is added we can also
# add a deprecation warning here.
with _ManageReload(fullname):
module = _call_with_frames_removed(_imp.init_builtin, fullname)
module.__loader__ = cls
module.__package__ = ''
return 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
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 ''.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
@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)
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=sys.version[:3])
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 = 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 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__))
_call_with_frames_removed(exec, code, module.__dict__)
load_module = _load_module_shim
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 IOError when the path cannot be handled.
"""
raise IOError
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 IOError 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 _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
try:
bytecode_path = cache_from_source(source_path)
except NotImplementedError:
bytecode_path = None
else:
try:
st = self.path_stats(source_path)
except IOError:
pass
else:
source_mtime = int(st['mtime'])
try:
data = self.get_data(bytecode_path)
except OSError:
pass
else:
try:
bytes_data = _validate_bytecode_header(data,
source_stats=st, name=fullname,
path=bytecode_path)
except (ImportError, EOFError):
pass
else:
_verbose_message('{} matches {}', bytecode_path,
source_path)
return _compile_bytecode(bytes_data, name=fullname,
bytecode_path=bytecode_path,
source_path=source_path)
source_bytes = self.get_data(source_path)
code_object = self.source_to_code(source_bytes, source_path)
_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):
data = _code_to_bytecode(code_object, source_mtime,
len(source_bytes))
try:
self._cache_bytecode(source_path, bytecode_path, data)
_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()
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.
_verbose_message('could not create {!r}: {!r}', parent, exc)
return
try:
_write_atomic(path, data, _mode)
_verbose_message('created {!r}', path)
except OSError as exc:
# Same as above: just don't write the bytecode.
_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)
bytes_data = _validate_bytecode_header(data, name=fullname, path=path)
return _compile_bytecode(bytes_data, 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:
"""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)
@_check_name
def load_module(self, fullname):
"""Load an extension module."""
# Once an exec_module() implementation is added we can also
# add a deprecation warning here.
with _ManageReload(fullname):
module = _call_with_frames_removed(_imp.load_dynamic,
fullname, self.path)
_verbose_message('extension module loaded from {!r}', self.path)
is_package = self.is_package(fullname)
if is_package and not hasattr(module, '__path__'):
module.__path__ = [_path_split(self.path)[0]]
module.__loader__ = self
module.__package__ = module.__name__
if not is_package:
module.__package__ = module.__package__.rpartition('.')[0]
return module
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 __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 init_module_attrs() 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 ''.format(module.__name__)
def is_package(self, fullname):
return True
def get_source(self, fullname):
return ''
def get_code(self, fullname):
return compile('', '', 'exec', dont_inherit=True)
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.
_verbose_message('namespace module loaded with path {!r}', self._path)
return _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 finder in sys.path_importer_cache.values():
if hasattr(finder, 'invalidate_caches'):
finder.invalidate_caches()
@classmethod
def _path_hooks(cls, path):
"""Search sequence of hooks for a finder for 'path'.
If 'hooks' is false then use sys.path_hooks.
"""
if 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 == '':
path = _os.getcwd()
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 spec_from_loader(fullname, loader)
spec = 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 = ModuleSpec(fullname, None)
spec.submodule_search_locations = namespace_path
return spec
@classmethod
def find_spec(cls, fullname, path=None, target=None):
"""find the module on sys.path or 'path' 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 = 'namespace'
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 loader for the specified module, or the namespace
package portions. Returns (loader, list-of-portions)."""
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)
_verbose_message('trying {}'.format(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:
_verbose_message('possible namespace for {}'.format(base_path))
spec = 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 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 loader."""
if not sys.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 sys.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 package:
if not isinstance(package, str):
raise TypeError('__package__ not set to a string')
elif package not in sys.modules:
msg = ('Parent module {!r} not loaded, cannot perform relative '
'import')
raise SystemError(msg.format(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 ImportError(msg, name=name)
spec = _find_spec(name, path)
if spec is None:
raise ImportError(_ERR_MSG.format(name), name=name)
else:
module = _SpecMethods(spec)._load_unlocked()
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
def _find_and_load(name, import_):
"""Find and load the module, and release the import lock."""
with _ModuleLockManager(name):
return _find_and_load_unlocked(name, import_)
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)
_imp.acquire_lock()
if name not in sys.modules:
return _find_and_load(name, _gcd_import)
module = sys.modules[name]
if module is None:
_imp.release_lock()
message = ('import of {} halted; '
'None in sys.modules'.format(name))
raise ImportError(message, name=name)
_lock_unlock_module(name)
return module
def _handle_fromlist(module, fromlist, import_):
"""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__'):
if '*' in fromlist:
fromlist = list(fromlist)
fromlist.remove('*')
if hasattr(module, '__all__'):
fromlist.extend(module.__all__)
for x in fromlist:
if not hasattr(module, x):
from_name = '{}.{}'.format(module.__name__, x)
try:
_call_with_frames_removed(import_, from_name)
except ImportError as exc:
# Backwards-compatibility dictates we ignore failed
# imports triggered by fromlist for modules that don't
# exist.
if str(exc).startswith(_ERR_MSG_PREFIX):
if exc.name == from_name:
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__')
if package is None:
package = globals['__name__']
if '__path__' not in globals:
package = package.rpartition('.')[0]
return package
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 __import__(name, globals=None, locals=None, fromlist=(), level=0):
"""Import a module.
The 'globals' argument is used to infer where the import is occuring 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 ``). 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)
methods = _SpecMethods(spec)
return methods._load_unlocked()
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, BYTECODE_SUFFIXES
_imp = _imp_module
sys = sys_module
if sys.flags.optimize:
BYTECODE_SUFFIXES = OPTIMIZED_BYTECODE_SUFFIXES
else:
BYTECODE_SUFFIXES = DEBUG_BYTECODE_SUFFIXES
# 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)
methods = _SpecMethods(spec)
methods.init_module_attrs(module)
# 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 = _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 = _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).
try:
thread_module = _builtin_from_name('_thread')
except ImportError:
# Python was built without threads
thread_module = None
setattr(self_module, '_thread', thread_module)
# Directly load the _weakref module (needed during bootstrap).
weakref_module = _builtin_from_name('_weakref')
setattr(self_module, '_weakref', weakref_module)
# Directly load the winreg module (needed during bootstrap).
if builtin_os == 'nt':
winreg_module = _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(sys_module, _imp_module):
"""Install importlib as the implementation of import."""
_setup(sys_module, _imp_module)
supported_loaders = _get_supported_file_loaders()
sys.path_hooks.extend([FileFinder.path_hook(*supported_loaders)])
sys.meta_path.append(BuiltinImporter)
sys.meta_path.append(FrozenImporter)
if _os.__name__ == 'nt':
sys.meta_path.append(WindowsRegistryFinder)
sys.meta_path.append(PathFinder)
import sys
print(sys.platform)
#if sys.platform.startswith(_CASE_INSENSITIVE_PLATFORMS):
#print(sys.modules)