mirror of
https://github.com/python/cpython.git
synced 2025-11-04 11:49:12 +00:00
202 lines
7.1 KiB
Python
202 lines
7.1 KiB
Python
"""Utility code for constructing importers, etc."""
|
|
|
|
from ._bootstrap import MAGIC_NUMBER
|
|
from ._bootstrap import cache_from_source
|
|
from ._bootstrap import decode_source
|
|
from ._bootstrap import source_from_cache
|
|
from ._bootstrap import spec_from_loader
|
|
from ._bootstrap import spec_from_file_location
|
|
from ._bootstrap import _resolve_name
|
|
from ._bootstrap import _find_spec
|
|
|
|
from contextlib import contextmanager
|
|
import functools
|
|
import sys
|
|
import warnings
|
|
|
|
|
|
def resolve_name(name, package):
|
|
"""Resolve a relative module name to an absolute one."""
|
|
if not name.startswith('.'):
|
|
return name
|
|
elif not package:
|
|
raise ValueError('{!r} is not a relative name '
|
|
'(no leading dot)'.format(name))
|
|
level = 0
|
|
for character in name:
|
|
if character != '.':
|
|
break
|
|
level += 1
|
|
return _resolve_name(name[level:], package, level)
|
|
|
|
|
|
def _find_spec_from_path(name, path=None):
|
|
"""Return the spec for the specified module.
|
|
|
|
First, sys.modules is checked to see if the module was already imported. If
|
|
so, then sys.modules[name].__spec__ is returned. If that happens to be
|
|
set to None, then ValueError is raised. If the module is not in
|
|
sys.modules, then sys.meta_path is searched for a suitable spec with the
|
|
value of 'path' given to the finders. None is returned if no spec could
|
|
be found.
|
|
|
|
Dotted names do not have their parent packages implicitly imported. You will
|
|
most likely need to explicitly import all parent packages in the proper
|
|
order for a submodule to get the correct spec.
|
|
|
|
"""
|
|
if name not in sys.modules:
|
|
return _find_spec(name, path)
|
|
else:
|
|
module = sys.modules[name]
|
|
if module is None:
|
|
return None
|
|
try:
|
|
spec = module.__spec__
|
|
except AttributeError:
|
|
raise ValueError('{}.__spec__ is not set'.format(name))
|
|
else:
|
|
if spec is None:
|
|
raise ValueError('{}.__spec__ is None'.format(name))
|
|
return spec
|
|
|
|
|
|
def find_spec(name, package=None):
|
|
"""Return the spec for the specified module.
|
|
|
|
First, sys.modules is checked to see if the module was already imported. If
|
|
so, then sys.modules[name].__spec__ is returned. If that happens to be
|
|
set to None, then ValueError is raised. If the module is not in
|
|
sys.modules, then sys.meta_path is searched for a suitable spec with the
|
|
value of 'path' given to the finders. None is returned if no spec could
|
|
be found.
|
|
|
|
If the name is for submodule (contains a dot), the parent module is
|
|
automatically imported.
|
|
|
|
The name and package arguments work the same as importlib.import_module().
|
|
In other words, relative module names (with leading dots) work.
|
|
|
|
"""
|
|
fullname = resolve_name(name, package) if name.startswith('.') else name
|
|
if fullname not in sys.modules:
|
|
parent_name = fullname.rpartition('.')[0]
|
|
if parent_name:
|
|
# Use builtins.__import__() in case someone replaced it.
|
|
parent = __import__(parent_name, fromlist=['__path__'])
|
|
return _find_spec(fullname, parent.__path__)
|
|
else:
|
|
return _find_spec(fullname, None)
|
|
else:
|
|
module = sys.modules[fullname]
|
|
if module is None:
|
|
return None
|
|
try:
|
|
spec = module.__spec__
|
|
except AttributeError:
|
|
raise ValueError('{}.__spec__ is not set'.format(name))
|
|
else:
|
|
if spec is None:
|
|
raise ValueError('{}.__spec__ is None'.format(name))
|
|
return spec
|
|
|
|
|
|
@contextmanager
|
|
def _module_to_load(name):
|
|
is_reload = name in sys.modules
|
|
|
|
module = sys.modules.get(name)
|
|
if not is_reload:
|
|
# This must be done before open() is called as the 'io' module
|
|
# implicitly imports 'locale' and would otherwise trigger an
|
|
# infinite loop.
|
|
module = type(sys)(name)
|
|
# This must be done before putting the module in sys.modules
|
|
# (otherwise an optimization shortcut in import.c becomes wrong)
|
|
module.__initializing__ = True
|
|
sys.modules[name] = module
|
|
try:
|
|
yield module
|
|
except Exception:
|
|
if not is_reload:
|
|
try:
|
|
del sys.modules[name]
|
|
except KeyError:
|
|
pass
|
|
finally:
|
|
module.__initializing__ = False
|
|
|
|
|
|
def set_package(fxn):
|
|
"""Set __package__ on the returned module.
|
|
|
|
This function is deprecated.
|
|
|
|
"""
|
|
@functools.wraps(fxn)
|
|
def set_package_wrapper(*args, **kwargs):
|
|
warnings.warn('The import system now takes care of this automatically.',
|
|
DeprecationWarning, stacklevel=2)
|
|
module = fxn(*args, **kwargs)
|
|
if getattr(module, '__package__', None) is None:
|
|
module.__package__ = module.__name__
|
|
if not hasattr(module, '__path__'):
|
|
module.__package__ = module.__package__.rpartition('.')[0]
|
|
return module
|
|
return set_package_wrapper
|
|
|
|
|
|
def set_loader(fxn):
|
|
"""Set __loader__ on the returned module.
|
|
|
|
This function is deprecated.
|
|
|
|
"""
|
|
@functools.wraps(fxn)
|
|
def set_loader_wrapper(self, *args, **kwargs):
|
|
warnings.warn('The import system now takes care of this automatically.',
|
|
DeprecationWarning, stacklevel=2)
|
|
module = fxn(self, *args, **kwargs)
|
|
if getattr(module, '__loader__', None) is None:
|
|
module.__loader__ = self
|
|
return module
|
|
return set_loader_wrapper
|
|
|
|
|
|
def module_for_loader(fxn):
|
|
"""Decorator to handle selecting the proper module for loaders.
|
|
|
|
The decorated function is passed the module to use instead of the module
|
|
name. The module passed in to the function is either from sys.modules if
|
|
it already exists or is a new module. If the module is new, then __name__
|
|
is set the first argument to the method, __loader__ is set to self, and
|
|
__package__ is set accordingly (if self.is_package() is defined) will be set
|
|
before it is passed to the decorated function (if self.is_package() does
|
|
not work for the module it will be set post-load).
|
|
|
|
If an exception is raised and the decorator created the module it is
|
|
subsequently removed from sys.modules.
|
|
|
|
The decorator assumes that the decorated function takes the module name as
|
|
the second argument.
|
|
|
|
"""
|
|
warnings.warn('The import system now takes care of this automatically.',
|
|
DeprecationWarning, stacklevel=2)
|
|
@functools.wraps(fxn)
|
|
def module_for_loader_wrapper(self, fullname, *args, **kwargs):
|
|
with _module_to_load(fullname) as module:
|
|
module.__loader__ = self
|
|
try:
|
|
is_package = self.is_package(fullname)
|
|
except (ImportError, AttributeError):
|
|
pass
|
|
else:
|
|
if is_package:
|
|
module.__package__ = fullname
|
|
else:
|
|
module.__package__ = fullname.rpartition('.')[0]
|
|
# If __package__ was not set above, __import__() will do it later.
|
|
return fxn(self, module, *args, **kwargs)
|
|
|
|
return module_for_loader_wrapper
|