1164 lines
40 KiB
Python
1164 lines
40 KiB
Python
"""Core implementation of import.
|
|
|
|
This module is NOT meant to be directly imported! It has been designed such
|
|
that it can be bootstrapped into Python as the implementation of import. As
|
|
such it requires the injection of specific modules and attributes in order to
|
|
work. One should use importlib as the public-facing version of this module.
|
|
|
|
"""
|
|
#
|
|
# IMPORTANT: Whenever making changes to this module, be sure to run
|
|
# a top-level make in order to get the frozen version of the module
|
|
# updated. Not doing so will result in the Makefile to fail for
|
|
# all others who don't have a ./python around to freeze the module
|
|
# in the early stages of compilation.
|
|
#
|
|
|
|
# See importlib._setup() for what is injected into the global namespace.
|
|
|
|
# When editing this code be aware that code executed at import time CANNOT
|
|
# reference any injected objects! This includes not only global code but also
|
|
# anything specified at the class level.
|
|
|
|
# Bootstrap-related code ######################################################
|
|
|
|
_bootstrap_external = None
|
|
|
|
def _wrap(new, old):
|
|
"""Simple substitute for functools.update_wrapper."""
|
|
for replace in ['__module__', '__name__', '__qualname__', '__doc__']:
|
|
if hasattr(old, replace):
|
|
setattr(new, replace, getattr(old, replace))
|
|
new.__dict__.update(old.__dict__)
|
|
|
|
|
|
def _new_module(name):
|
|
return type(sys)(name)
|
|
|
|
|
|
# Module-level locking ########################################################
|
|
|
|
# A dict mapping module names to weakrefs of _ModuleLock instances
|
|
# Dictionary protected by the global import lock
|
|
_module_locks = {}
|
|
# A dict mapping thread ids to _ModuleLock instances
|
|
_blocking_on = {}
|
|
|
|
|
|
class _DeadlockError(RuntimeError):
|
|
pass
|
|
|
|
|
|
class _ModuleLock:
|
|
"""A recursive lock implementation which is able to detect deadlocks
|
|
(e.g. thread 1 trying to take locks A then B, and thread 2 trying to
|
|
take locks B then A).
|
|
"""
|
|
|
|
def __init__(self, name):
|
|
self.lock = _thread.allocate_lock()
|
|
self.wakeup = _thread.allocate_lock()
|
|
self.name = name
|
|
self.owner = None
|
|
self.count = 0
|
|
self.waiters = 0
|
|
|
|
def has_deadlock(self):
|
|
# Deadlock avoidance for concurrent circular imports.
|
|
me = _thread.get_ident()
|
|
tid = self.owner
|
|
while True:
|
|
lock = _blocking_on.get(tid)
|
|
if lock is None:
|
|
return False
|
|
tid = lock.owner
|
|
if tid == me:
|
|
return True
|
|
|
|
def acquire(self):
|
|
"""
|
|
Acquire the module lock. If a potential deadlock is detected,
|
|
a _DeadlockError is raised.
|
|
Otherwise, the lock is always acquired and True is returned.
|
|
"""
|
|
tid = _thread.get_ident()
|
|
_blocking_on[tid] = self
|
|
try:
|
|
while True:
|
|
with self.lock:
|
|
if self.count == 0 or self.owner == tid:
|
|
self.owner = tid
|
|
self.count += 1
|
|
return True
|
|
if self.has_deadlock():
|
|
raise _DeadlockError('deadlock detected by %r' % self)
|
|
if self.wakeup.acquire(False):
|
|
self.waiters += 1
|
|
# Wait for a release() call
|
|
self.wakeup.acquire()
|
|
self.wakeup.release()
|
|
finally:
|
|
del _blocking_on[tid]
|
|
|
|
def release(self):
|
|
tid = _thread.get_ident()
|
|
with self.lock:
|
|
if self.owner != tid:
|
|
raise RuntimeError('cannot release un-acquired lock')
|
|
assert self.count > 0
|
|
self.count -= 1
|
|
if self.count == 0:
|
|
self.owner = None
|
|
if self.waiters:
|
|
self.waiters -= 1
|
|
self.wakeup.release()
|
|
|
|
def __repr__(self):
|
|
return '_ModuleLock({!r}) at {}'.format(self.name, id(self))
|
|
|
|
|
|
class _DummyModuleLock:
|
|
"""A simple _ModuleLock equivalent for Python builds without
|
|
multi-threading support."""
|
|
|
|
def __init__(self, name):
|
|
self.name = name
|
|
self.count = 0
|
|
|
|
def acquire(self):
|
|
self.count += 1
|
|
return True
|
|
|
|
def release(self):
|
|
if self.count == 0:
|
|
raise RuntimeError('cannot release un-acquired lock')
|
|
self.count -= 1
|
|
|
|
def __repr__(self):
|
|
return '_DummyModuleLock({!r}) at {}'.format(self.name, id(self))
|
|
|
|
|
|
class _ModuleLockManager:
|
|
|
|
def __init__(self, name):
|
|
self._name = name
|
|
self._lock = None
|
|
|
|
def __enter__(self):
|
|
self._lock = _get_module_lock(self._name)
|
|
self._lock.acquire()
|
|
|
|
def __exit__(self, *args, **kwargs):
|
|
self._lock.release()
|
|
|
|
|
|
# The following two functions are for consumption by Python/import.c.
|
|
|
|
def _get_module_lock(name):
|
|
"""Get or create the module lock for a given module name.
|
|
|
|
Acquire/release internally the global import lock to protect
|
|
_module_locks."""
|
|
|
|
_imp.acquire_lock()
|
|
try:
|
|
try:
|
|
lock = _module_locks[name]()
|
|
except KeyError:
|
|
lock = None
|
|
|
|
if lock is None:
|
|
if _thread is None:
|
|
lock = _DummyModuleLock(name)
|
|
else:
|
|
lock = _ModuleLock(name)
|
|
|
|
def cb(ref, name=name):
|
|
_imp.acquire_lock()
|
|
try:
|
|
# bpo-31070: Check if another thread created a new lock
|
|
# after the previous lock was destroyed
|
|
# but before the weakref callback was called.
|
|
if _module_locks.get(name) is ref:
|
|
del _module_locks[name]
|
|
finally:
|
|
_imp.release_lock()
|
|
|
|
_module_locks[name] = _weakref.ref(lock, cb)
|
|
finally:
|
|
_imp.release_lock()
|
|
|
|
return lock
|
|
|
|
|
|
def _lock_unlock_module(name):
|
|
"""Acquires then releases the module lock for a given module name.
|
|
|
|
This is used to ensure a module is completely initialized, in the
|
|
event it is being imported by another thread.
|
|
"""
|
|
lock = _get_module_lock(name)
|
|
try:
|
|
lock.acquire()
|
|
except _DeadlockError:
|
|
# Concurrent circular import, we'll accept a partially initialized
|
|
# module object.
|
|
pass
|
|
else:
|
|
lock.release()
|
|
|
|
# Frame stripping magic ###############################################
|
|
def _call_with_frames_removed(f, *args, **kwds):
|
|
"""remove_importlib_frames in import.c will always remove sequences
|
|
of importlib frames that end with a call to this function
|
|
|
|
Use it instead of a normal call in places where including the importlib
|
|
frames introduces unwanted noise into the traceback (e.g. when executing
|
|
module code)
|
|
"""
|
|
return f(*args, **kwds)
|
|
|
|
|
|
def _verbose_message(message, *args, verbosity=1):
|
|
"""Print the message to stderr if -v/PYTHONVERBOSE is turned on."""
|
|
if sys.flags.verbose >= verbosity:
|
|
if not message.startswith(('#', 'import ')):
|
|
message = '# ' + message
|
|
print(message.format(*args), file=sys.stderr)
|
|
|
|
|
|
def _requires_builtin(fxn):
|
|
"""Decorator to verify the named module is built-in."""
|
|
def _requires_builtin_wrapper(self, fullname):
|
|
if fullname not in sys.builtin_module_names:
|
|
raise ImportError('{!r} is not a built-in module'.format(fullname),
|
|
name=fullname)
|
|
return fxn(self, fullname)
|
|
_wrap(_requires_builtin_wrapper, fxn)
|
|
return _requires_builtin_wrapper
|
|
|
|
|
|
def _requires_frozen(fxn):
|
|
"""Decorator to verify the named module is frozen."""
|
|
def _requires_frozen_wrapper(self, fullname):
|
|
if not _imp.is_frozen(fullname):
|
|
raise ImportError('{!r} is not a frozen module'.format(fullname),
|
|
name=fullname)
|
|
return fxn(self, fullname)
|
|
_wrap(_requires_frozen_wrapper, fxn)
|
|
return _requires_frozen_wrapper
|
|
|
|
|
|
# Typically used by loader classes as a method replacement.
|
|
def _load_module_shim(self, fullname):
|
|
"""Load the specified module into sys.modules and return it.
|
|
|
|
This method is deprecated. Use loader.exec_module instead.
|
|
|
|
"""
|
|
spec = spec_from_loader(fullname, self)
|
|
if fullname in sys.modules:
|
|
module = sys.modules[fullname]
|
|
_exec(spec, module)
|
|
return sys.modules[fullname]
|
|
else:
|
|
return _load(spec)
|
|
|
|
# Module specifications #######################################################
|
|
|
|
def _module_repr(module):
|
|
# The implementation of ModuleType.__repr__().
|
|
loader = getattr(module, '__loader__', None)
|
|
if hasattr(loader, 'module_repr'):
|
|
# As soon as BuiltinImporter, FrozenImporter, and NamespaceLoader
|
|
# drop their implementations for module_repr. we can add a
|
|
# deprecation warning here.
|
|
try:
|
|
return loader.module_repr(module)
|
|
except Exception:
|
|
pass
|
|
try:
|
|
spec = module.__spec__
|
|
except AttributeError:
|
|
pass
|
|
else:
|
|
if spec is not None:
|
|
return _module_repr_from_spec(spec)
|
|
|
|
# We could use module.__class__.__name__ instead of 'module' in the
|
|
# various repr permutations.
|
|
try:
|
|
name = module.__name__
|
|
except AttributeError:
|
|
name = '?'
|
|
try:
|
|
filename = module.__file__
|
|
except AttributeError:
|
|
if loader is None:
|
|
return '<module {!r}>'.format(name)
|
|
else:
|
|
return '<module {!r} ({!r})>'.format(name, loader)
|
|
else:
|
|
return '<module {!r} from {!r}>'.format(name, filename)
|
|
|
|
|
|
class _installed_safely:
|
|
|
|
def __init__(self, module):
|
|
self._module = module
|
|
self._spec = module.__spec__
|
|
|
|
def __enter__(self):
|
|
# This must be done before putting the module in sys.modules
|
|
# (otherwise an optimization shortcut in import.c becomes
|
|
# wrong)
|
|
self._spec._initializing = True
|
|
sys.modules[self._spec.name] = self._module
|
|
|
|
def __exit__(self, *args):
|
|
try:
|
|
spec = self._spec
|
|
if any(arg is not None for arg in args):
|
|
try:
|
|
del sys.modules[spec.name]
|
|
except KeyError:
|
|
pass
|
|
else:
|
|
_verbose_message('import {!r} # {!r}', spec.name, spec.loader)
|
|
finally:
|
|
self._spec._initializing = False
|
|
|
|
|
|
class ModuleSpec:
|
|
"""The specification for a module, used for loading.
|
|
|
|
A module's spec is the source for information about the module. For
|
|
data associated with the module, including source, use the spec's
|
|
loader.
|
|
|
|
`name` is the absolute name of the module. `loader` is the loader
|
|
to use when loading the module. `parent` is the name of the
|
|
package the module is in. The parent is derived from the name.
|
|
|
|
`is_package` determines if the module is considered a package or
|
|
not. On modules this is reflected by the `__path__` attribute.
|
|
|
|
`origin` is the specific location used by the loader from which to
|
|
load the module, if that information is available. When filename is
|
|
set, origin will match.
|
|
|
|
`has_location` indicates that a spec's "origin" reflects a location.
|
|
When this is True, `__file__` attribute of the module is set.
|
|
|
|
`cached` is the location of the cached bytecode file, if any. It
|
|
corresponds to the `__cached__` attribute.
|
|
|
|
`submodule_search_locations` is the sequence of path entries to
|
|
search when importing submodules. If set, is_package should be
|
|
True--and False otherwise.
|
|
|
|
Packages are simply modules that (may) have submodules. If a spec
|
|
has a non-None value in `submodule_search_locations`, the import
|
|
system will consider modules loaded from the spec as packages.
|
|
|
|
Only finders (see importlib.abc.MetaPathFinder and
|
|
importlib.abc.PathEntryFinder) should modify ModuleSpec instances.
|
|
|
|
"""
|
|
|
|
def __init__(self, name, loader, *, origin=None, loader_state=None,
|
|
is_package=None):
|
|
self.name = name
|
|
self.loader = loader
|
|
self.origin = origin
|
|
self.loader_state = loader_state
|
|
self.submodule_search_locations = [] if is_package else None
|
|
|
|
# file-location attributes
|
|
self._set_fileattr = False
|
|
self._cached = None
|
|
|
|
def __repr__(self):
|
|
args = ['name={!r}'.format(self.name),
|
|
'loader={!r}'.format(self.loader)]
|
|
if self.origin is not None:
|
|
args.append('origin={!r}'.format(self.origin))
|
|
if self.submodule_search_locations is not None:
|
|
args.append('submodule_search_locations={}'
|
|
.format(self.submodule_search_locations))
|
|
return '{}({})'.format(self.__class__.__name__, ', '.join(args))
|
|
|
|
def __eq__(self, other):
|
|
smsl = self.submodule_search_locations
|
|
try:
|
|
return (self.name == other.name and
|
|
self.loader == other.loader and
|
|
self.origin == other.origin and
|
|
smsl == other.submodule_search_locations and
|
|
self.cached == other.cached and
|
|
self.has_location == other.has_location)
|
|
except AttributeError:
|
|
return False
|
|
|
|
@property
|
|
def cached(self):
|
|
if self._cached is None:
|
|
if self.origin is not None and self._set_fileattr:
|
|
if _bootstrap_external is None:
|
|
raise NotImplementedError
|
|
self._cached = _bootstrap_external._get_cached(self.origin)
|
|
return self._cached
|
|
|
|
@cached.setter
|
|
def cached(self, cached):
|
|
self._cached = cached
|
|
|
|
@property
|
|
def parent(self):
|
|
"""The name of the module's parent."""
|
|
if self.submodule_search_locations is None:
|
|
return self.name.rpartition('.')[0]
|
|
else:
|
|
return self.name
|
|
|
|
@property
|
|
def has_location(self):
|
|
return self._set_fileattr
|
|
|
|
@has_location.setter
|
|
def has_location(self, value):
|
|
self._set_fileattr = bool(value)
|
|
|
|
|
|
def spec_from_loader(name, loader, *, origin=None, is_package=None):
|
|
"""Return a module spec based on various loader methods."""
|
|
if hasattr(loader, 'get_filename'):
|
|
if _bootstrap_external is None:
|
|
raise NotImplementedError
|
|
spec_from_file_location = _bootstrap_external.spec_from_file_location
|
|
|
|
if is_package is None:
|
|
return spec_from_file_location(name, loader=loader)
|
|
search = [] if is_package else None
|
|
return spec_from_file_location(name, loader=loader,
|
|
submodule_search_locations=search)
|
|
|
|
if is_package is None:
|
|
if hasattr(loader, 'is_package'):
|
|
try:
|
|
is_package = loader.is_package(name)
|
|
except ImportError:
|
|
is_package = None # aka, undefined
|
|
else:
|
|
# the default
|
|
is_package = False
|
|
|
|
return ModuleSpec(name, loader, origin=origin, is_package=is_package)
|
|
|
|
|
|
def _spec_from_module(module, loader=None, origin=None):
|
|
# This function is meant for use in _setup().
|
|
try:
|
|
spec = module.__spec__
|
|
except AttributeError:
|
|
pass
|
|
else:
|
|
if spec is not None:
|
|
return spec
|
|
|
|
name = module.__name__
|
|
if loader is None:
|
|
try:
|
|
loader = module.__loader__
|
|
except AttributeError:
|
|
# loader will stay None.
|
|
pass
|
|
try:
|
|
location = module.__file__
|
|
except AttributeError:
|
|
location = None
|
|
if origin is None:
|
|
if location is None:
|
|
try:
|
|
origin = loader._ORIGIN
|
|
except AttributeError:
|
|
origin = None
|
|
else:
|
|
origin = location
|
|
try:
|
|
cached = module.__cached__
|
|
except AttributeError:
|
|
cached = None
|
|
try:
|
|
submodule_search_locations = list(module.__path__)
|
|
except AttributeError:
|
|
submodule_search_locations = None
|
|
|
|
spec = ModuleSpec(name, loader, origin=origin)
|
|
spec._set_fileattr = False if location is None else True
|
|
spec.cached = cached
|
|
spec.submodule_search_locations = submodule_search_locations
|
|
return spec
|
|
|
|
|
|
def _init_module_attrs(spec, module, *, override=False):
|
|
# The passed-in module may be not support attribute assignment,
|
|
# in which case we simply don't set the attributes.
|
|
# __name__
|
|
if (override 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:
|
|
if _bootstrap_external is None:
|
|
raise NotImplementedError
|
|
_NamespaceLoader = _bootstrap_external._NamespaceLoader
|
|
|
|
loader = _NamespaceLoader.__new__(_NamespaceLoader)
|
|
loader._path = spec.submodule_search_locations
|
|
spec.loader = loader
|
|
# While the docs say that module.__file__ is not set for
|
|
# built-in modules, and the code below will avoid setting it if
|
|
# spec.has_location is false, this is incorrect for namespace
|
|
# packages. Namespace packages have no location, but their
|
|
# __spec__.origin is None, and thus their module.__file__
|
|
# should also be None for consistency. While a bit of a hack,
|
|
# this is the best place to ensure this consistency.
|
|
#
|
|
# See # https://docs.python.org/3/library/importlib.html#importlib.abc.Loader.load_module
|
|
# and bpo-32305
|
|
module.__file__ = None
|
|
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
|
|
# __file__/__cached__
|
|
if spec.has_location:
|
|
if override or getattr(module, '__file__', None) is None:
|
|
try:
|
|
module.__file__ = spec.origin
|
|
except AttributeError:
|
|
pass
|
|
|
|
if override or getattr(module, '__cached__', None) is None:
|
|
if spec.cached is not None:
|
|
try:
|
|
module.__cached__ = spec.cached
|
|
except AttributeError:
|
|
pass
|
|
return module
|
|
|
|
|
|
def module_from_spec(spec):
|
|
"""Create a module based on the provided spec."""
|
|
# Typically loaders will not implement create_module().
|
|
module = None
|
|
if hasattr(spec.loader, 'create_module'):
|
|
# If create_module() returns `None` then it means default
|
|
# module creation should be used.
|
|
module = spec.loader.create_module(spec)
|
|
elif hasattr(spec.loader, 'exec_module'):
|
|
raise ImportError('loaders that define exec_module() '
|
|
'must also define create_module()')
|
|
if module is None:
|
|
module = _new_module(spec.name)
|
|
_init_module_attrs(spec, module)
|
|
return module
|
|
|
|
|
|
def _module_repr_from_spec(spec):
|
|
"""Return the repr to use for the module."""
|
|
# We mostly replicate _module_repr() using the spec attributes.
|
|
name = '?' if spec.name is None else spec.name
|
|
if spec.origin is None:
|
|
if spec.loader is None:
|
|
return '<module {!r}>'.format(name)
|
|
else:
|
|
return '<module {!r} ({!r})>'.format(name, spec.loader)
|
|
else:
|
|
if spec.has_location:
|
|
return '<module {!r} from {!r}>'.format(name, spec.origin)
|
|
else:
|
|
return '<module {!r} ({})>'.format(spec.name, spec.origin)
|
|
|
|
|
|
# Used by importlib.reload() and _load_module_shim().
|
|
def _exec(spec, module):
|
|
"""Execute the spec's specified module in an existing module's namespace."""
|
|
name = spec.name
|
|
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 spec.loader is None:
|
|
if spec.submodule_search_locations is None:
|
|
raise ImportError('missing loader', name=spec.name)
|
|
# namespace package
|
|
_init_module_attrs(spec, module, override=True)
|
|
return module
|
|
_init_module_attrs(spec, module, override=True)
|
|
if not hasattr(spec.loader, 'exec_module'):
|
|
# (issue19713) Once BuiltinImporter and ExtensionFileLoader
|
|
# have exec_module() implemented, we can add a deprecation
|
|
# warning here.
|
|
spec.loader.load_module(name)
|
|
else:
|
|
spec.loader.exec_module(module)
|
|
return sys.modules[name]
|
|
|
|
|
|
def _load_backward_compatible(spec):
|
|
# (issue19713) Once BuiltinImporter and ExtensionFileLoader
|
|
# have exec_module() implemented, we can add a deprecation
|
|
# warning here.
|
|
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(spec):
|
|
# A helper for direct use by the import system.
|
|
if spec.loader is not None:
|
|
# not a namespace package
|
|
if not hasattr(spec.loader, 'exec_module'):
|
|
return _load_backward_compatible(spec)
|
|
|
|
module = module_from_spec(spec)
|
|
with _installed_safely(module):
|
|
if spec.loader is None:
|
|
if spec.submodule_search_locations is None:
|
|
raise ImportError('missing loader', name=spec.name)
|
|
# A namespace package so do nothing.
|
|
else:
|
|
spec.loader.exec_module(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[spec.name]
|
|
|
|
# A method used during testing of _load_unlocked() and by
|
|
# _load_module_shim().
|
|
def _load(spec):
|
|
"""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.
|
|
|
|
"""
|
|
with _ModuleLockManager(spec.name):
|
|
return _load_unlocked(spec)
|
|
|
|
|
|
# Loaders #####################################################################
|
|
|
|
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 '<module {!r} (built-in)>'.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
|
|
def create_module(self, spec):
|
|
"""Create a built-in module"""
|
|
if spec.name not in sys.builtin_module_names:
|
|
raise ImportError('{!r} is not a built-in module'.format(spec.name),
|
|
name=spec.name)
|
|
return _call_with_frames_removed(_imp.create_builtin, spec)
|
|
|
|
@classmethod
|
|
def exec_module(self, module):
|
|
"""Exec a built-in module"""
|
|
_call_with_frames_removed(_imp.exec_builtin, 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
|
|
|
|
load_module = classmethod(_load_module_shim)
|
|
|
|
|
|
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 '<module {!r} (frozen)>'.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
|
|
|
|
@classmethod
|
|
def create_module(cls, spec):
|
|
"""Use default semantics for module creation."""
|
|
|
|
@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)
|
|
|
|
|
|
# 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 spec."""
|
|
meta_path = sys.meta_path
|
|
if meta_path is None:
|
|
# PyImport_Cleanup() is running or has been called.
|
|
raise ImportError("sys.meta_path is None, Python is likely "
|
|
"shutting down")
|
|
|
|
if not 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 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 level > 0:
|
|
if not isinstance(package, str):
|
|
raise TypeError('__package__ not set to a string')
|
|
elif not package:
|
|
raise ImportError('attempted relative import with no known parent '
|
|
'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 ModuleNotFoundError(msg, name=name) from None
|
|
spec = _find_spec(name, path)
|
|
if spec is None:
|
|
raise ModuleNotFoundError(_ERR_MSG.format(name), name=name)
|
|
else:
|
|
module = _load_unlocked(spec)
|
|
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
|
|
|
|
|
|
_NEEDS_LOADING = object()
|
|
|
|
|
|
def _find_and_load(name, import_):
|
|
"""Find and load the module."""
|
|
with _ModuleLockManager(name):
|
|
module = sys.modules.get(name, _NEEDS_LOADING)
|
|
if module is _NEEDS_LOADING:
|
|
return _find_and_load_unlocked(name, import_)
|
|
|
|
if module is None:
|
|
message = ('import of {} halted; '
|
|
'None in sys.modules'.format(name))
|
|
raise ModuleNotFoundError(message, name=name)
|
|
|
|
_lock_unlock_module(name)
|
|
return module
|
|
|
|
|
|
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)
|
|
return _find_and_load(name, _gcd_import)
|
|
|
|
|
|
def _handle_fromlist(module, fromlist, import_, *, recursive=False):
|
|
"""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__'):
|
|
for x in fromlist:
|
|
if not isinstance(x, str):
|
|
if recursive:
|
|
where = module.__name__ + '.__all__'
|
|
else:
|
|
where = "``from list''"
|
|
raise TypeError(f"Item in {where} must be str, "
|
|
f"not {type(x).__name__}")
|
|
elif x == '*':
|
|
if not recursive and hasattr(module, '__all__'):
|
|
_handle_fromlist(module, module.__all__, import_,
|
|
recursive=True)
|
|
elif not hasattr(module, x):
|
|
from_name = '{}.{}'.format(module.__name__, x)
|
|
try:
|
|
_call_with_frames_removed(import_, from_name)
|
|
except ModuleNotFoundError as exc:
|
|
# Backwards-compatibility dictates we ignore failed
|
|
# imports triggered by fromlist for modules that don't
|
|
# exist.
|
|
if (exc.name == from_name and
|
|
sys.modules.get(from_name, _NEEDS_LOADING) is not None):
|
|
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__')
|
|
spec = globals.get('__spec__')
|
|
if package is not None:
|
|
if spec is not None and package != spec.parent:
|
|
_warnings.warn("__package__ != __spec__.parent "
|
|
f"({package!r} != {spec.parent!r})",
|
|
ImportWarning, stacklevel=3)
|
|
return package
|
|
elif spec is not None:
|
|
return spec.parent
|
|
else:
|
|
_warnings.warn("can't resolve package from __spec__ or __package__, "
|
|
"falling back on __name__ and __path__",
|
|
ImportWarning, stacklevel=3)
|
|
package = globals['__name__']
|
|
if '__path__' not in globals:
|
|
package = package.rpartition('.')[0]
|
|
return package
|
|
|
|
|
|
def __import__(name, globals=None, locals=None, fromlist=(), level=0):
|
|
"""Import a module.
|
|
|
|
The 'globals' argument is used to infer where the import is occurring 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 <fromlist>``). 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)
|
|
return _load_unlocked(spec)
|
|
|
|
|
|
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
|
|
_imp = _imp_module
|
|
sys = sys_module
|
|
|
|
# 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)
|
|
_init_module_attrs(spec, module)
|
|
|
|
# Directly load built-in modules needed during bootstrap.
|
|
self_module = sys.modules[__name__]
|
|
for builtin_name in ('_thread', '_warnings', '_weakref'):
|
|
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)
|
|
|
|
|
|
def _install(sys_module, _imp_module):
|
|
"""Install importers for builtin and frozen modules"""
|
|
_setup(sys_module, _imp_module)
|
|
|
|
sys.meta_path.append(BuiltinImporter)
|
|
sys.meta_path.append(FrozenImporter)
|
|
|
|
|
|
def _install_external_importers():
|
|
"""Install importers that require external filesystem access"""
|
|
global _bootstrap_external
|
|
import _frozen_importlib_external
|
|
_bootstrap_external = _frozen_importlib_external
|
|
_frozen_importlib_external._install(sys.modules[__name__])
|