mirror of
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977 lines
32 KiB
Python
977 lines
32 KiB
Python
"""Core implementation of import.
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This module is NOT meant to be directly imported! It has been designed such
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that it can be bootstrapped into Python as the implementation of import. As
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such it requires the injection of specific modules and attributes in order to
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work. One should use importlib as the public-facing version of this module.
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"""
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# Injected modules are '_warnings', 'imp', 'sys', 'marshal', 'errno', '_io',
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# and '_os' (a.k.a. 'posix', 'nt' or 'os2').
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# Injected attribute is path_sep.
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#
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# When editing this code be aware that code executed at import time CANNOT
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# reference any injected objects! This includes not only global code but also
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# anything specified at the class level.
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# Bootstrap-related code ######################################################
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# XXX Could also expose Modules/getpath.c:joinpath()
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def _path_join(*args):
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"""Replacement for os.path.join."""
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return path_sep.join(x[:-len(path_sep)] if x.endswith(path_sep) else x
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for x in args)
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def _path_exists(path):
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"""Replacement for os.path.exists."""
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try:
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_os.stat(path)
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except OSError:
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return False
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else:
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return True
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def _path_is_mode_type(path, mode):
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"""Test whether the path is the specified mode type."""
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try:
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stat_info = _os.stat(path)
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except OSError:
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return False
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return (stat_info.st_mode & 0o170000) == mode
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# XXX Could also expose Modules/getpath.c:isfile()
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def _path_isfile(path):
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"""Replacement for os.path.isfile."""
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return _path_is_mode_type(path, 0o100000)
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# XXX Could also expose Modules/getpath.c:isdir()
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def _path_isdir(path):
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"""Replacement for os.path.isdir."""
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return _path_is_mode_type(path, 0o040000)
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def _path_without_ext(path, ext_type):
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"""Replacement for os.path.splitext()[0]."""
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for suffix in _suffix_list(ext_type):
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if path.endswith(suffix):
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return path[:-len(suffix)]
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else:
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raise ValueError("path is not of the specified type")
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def _path_absolute(path):
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"""Replacement for os.path.abspath."""
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if not path:
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path = _os.getcwd()
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try:
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return _os._getfullpathname(path)
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except AttributeError:
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if path.startswith('/'):
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return path
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else:
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return _path_join(_os.getcwd(), path)
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class _closing:
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"""Simple replacement for contextlib.closing."""
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def __init__(self, obj):
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self.obj = obj
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def __enter__(self):
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return self.obj
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def __exit__(self, *args):
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self.obj.close()
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def _wrap(new, old):
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"""Simple substitute for functools.wraps."""
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for replace in ['__module__', '__name__', '__doc__']:
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setattr(new, replace, getattr(old, replace))
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new.__dict__.update(old.__dict__)
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# Finder/loader utility code ##################################################
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def set_package(fxn):
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"""Set __package__ on the returned module."""
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def wrapper(*args, **kwargs):
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module = fxn(*args, **kwargs)
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if not hasattr(module, '__package__') or module.__package__ is None:
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module.__package__ = module.__name__
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if not hasattr(module, '__path__'):
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module.__package__ = module.__package__.rpartition('.')[0]
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return module
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_wrap(wrapper, fxn)
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return wrapper
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def set_loader(fxn):
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"""Set __loader__ on the returned module."""
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def wrapper(self, *args, **kwargs):
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module = fxn(self, *args, **kwargs)
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if not hasattr(module, '__loader__'):
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module.__loader__ = self
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return module
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_wrap(wrapper, fxn)
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return wrapper
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def module_for_loader(fxn):
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"""Decorator to handle selecting the proper module for loaders.
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The decorated function is passed the module to use instead of the module
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name. The module passed in to the function is either from sys.modules if
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it already exists or is a new module which has __name__ set and is inserted
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into sys.modules. If an exception is raised and the decorator created the
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module it is subsequently removed from sys.modules.
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The decorator assumes that the decorated function takes the module name as
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the second argument.
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"""
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def decorated(self, fullname):
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module = sys.modules.get(fullname)
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is_reload = bool(module)
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if not is_reload:
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# This must be done before open() is called as the 'io' module
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# implicitly imports 'locale' and would otherwise trigger an
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# infinite loop.
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module = imp.new_module(fullname)
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sys.modules[fullname] = module
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try:
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return fxn(self, module)
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except:
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if not is_reload:
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del sys.modules[fullname]
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raise
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_wrap(decorated, fxn)
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return decorated
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def _check_name(method):
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"""Decorator to verify that the module being requested matches the one the
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loader can handle.
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The first argument (self) must define _name which the second argument is
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comapred against. If the comparison fails then ImportError is raised.
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"""
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def inner(self, name, *args, **kwargs):
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if self._name != name:
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raise ImportError("loader cannot handle %s" % name)
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return method(self, name, *args, **kwargs)
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_wrap(inner, method)
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return inner
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def _requires_builtin(fxn):
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"""Decorator to verify the named module is built-in."""
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def wrapper(self, fullname):
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if fullname not in sys.builtin_module_names:
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raise ImportError("{0} is not a built-in module".format(fullname))
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return fxn(self, fullname)
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_wrap(wrapper, fxn)
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return wrapper
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def _requires_frozen(fxn):
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"""Decorator to verify the named module is frozen."""
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def wrapper(self, fullname):
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if not imp.is_frozen(fullname):
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raise ImportError("{0} is not a frozen module".format(fullname))
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return fxn(self, fullname)
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_wrap(wrapper, fxn)
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return wrapper
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def _suffix_list(suffix_type):
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"""Return a list of file suffixes based on the imp file type."""
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return [suffix[0] for suffix in imp.get_suffixes()
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if suffix[2] == suffix_type]
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# Loaders #####################################################################
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class BuiltinImporter:
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"""Meta path import for built-in modules.
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All methods are either class or static methods to avoid the need to
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instantiate the class.
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"""
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@classmethod
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def find_module(cls, fullname, path=None):
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"""Find the built-in module.
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If 'path' is ever specified then the search is considered a failure.
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"""
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if path is not None:
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return None
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return cls if imp.is_builtin(fullname) else None
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@classmethod
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@set_package
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@set_loader
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@_requires_builtin
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def load_module(cls, fullname):
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"""Load a built-in module."""
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is_reload = fullname in sys.modules
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try:
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return imp.init_builtin(fullname)
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except:
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if not is_reload and fullname in sys.modules:
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del sys.modules[fullname]
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raise
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@classmethod
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@_requires_builtin
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def get_code(cls, fullname):
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"""Return None as built-in modules do not have code objects."""
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return None
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@classmethod
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@_requires_builtin
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def get_source(cls, fullname):
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"""Return None as built-in modules do not have source code."""
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return None
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@classmethod
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@_requires_builtin
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def is_package(cls, fullname):
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"""Return None as built-in module are never packages."""
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return False
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class FrozenImporter:
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"""Meta path import for frozen modules.
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All methods are either class or static methods to avoid the need to
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instantiate the class.
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"""
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@classmethod
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def find_module(cls, fullname, path=None):
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"""Find a frozen module."""
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return cls if imp.is_frozen(fullname) else None
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@classmethod
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@set_package
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@set_loader
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@_requires_frozen
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def load_module(cls, fullname):
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"""Load a frozen module."""
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is_reload = fullname in sys.modules
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try:
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return imp.init_frozen(fullname)
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except:
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if not is_reload and fullname in sys.modules:
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del sys.modules[fullname]
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raise
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@classmethod
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@_requires_frozen
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def get_code(cls, fullname):
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"""Return the code object for the frozen module."""
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return imp.get_frozen_object(fullname)
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@classmethod
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@_requires_frozen
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def get_source(cls, fullname):
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"""Return None as frozen modules do not have source code."""
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return None
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@classmethod
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@_requires_frozen
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def is_package(cls, fullname):
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"""Return if the frozen module is a package."""
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return imp.is_frozen_package(fullname)
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class PyLoader:
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"""Loader base class for Python source code.
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Subclasses need to implement the methods:
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- source_path
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- get_data
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- is_package
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"""
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@module_for_loader
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def load_module(self, module):
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"""Initialize the module."""
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name = module.__name__
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code_object = self.get_code(module.__name__)
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module.__file__ = self.get_filename(name)
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if self.is_package(name):
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module.__path__ = [module.__file__.rsplit(path_sep, 1)[0]]
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module.__package__ = module.__name__
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if not hasattr(module, '__path__'):
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module.__package__ = module.__package__.rpartition('.')[0]
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module.__loader__ = self
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exec(code_object, module.__dict__)
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return module
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def get_filename(self, fullname):
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"""Return the path to the source file, else raise ImportError."""
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path = self.source_path(fullname)
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if path is not None:
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return path
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else:
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raise ImportError("no source path available for "
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"{0!r}".format(fullname))
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def get_code(self, fullname):
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"""Get a code object from source."""
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source_path = self.source_path(fullname)
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if source_path is None:
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message = "a source path must exist to load {0}".format(fullname)
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raise ImportError(message)
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source = self.get_data(source_path)
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return compile(source, source_path, 'exec', dont_inherit=True)
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# Never use in implementing import! Imports code within the method.
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def get_source(self, fullname):
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"""Return the source code for a module.
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self.source_path() and self.get_data() are used to implement this
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method.
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"""
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path = self.source_path(fullname)
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if path is None:
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return None
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try:
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source_bytes = self.get_data(path)
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except IOError:
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return ImportError("source not available through get_data()")
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import io
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import tokenize
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encoding = tokenize.detect_encoding(io.BytesIO(source_bytes).readline)
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return source_bytes.decode(encoding[0])
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class PyPycLoader(PyLoader):
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"""Loader base class for Python source and bytecode.
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Requires implementing the methods needed for PyLoader as well as
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source_mtime, bytecode_path, and write_bytecode.
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"""
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def get_filename(self, fullname):
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"""Return the source or bytecode file path."""
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path = self.source_path(fullname)
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if path is not None:
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return path
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path = self.bytecode_path(fullname)
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if path is not None:
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return path
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raise ImportError("no source or bytecode path available for "
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"{0!r}".format(fullname))
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def get_code(self, fullname):
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"""Get a code object from source or bytecode."""
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# XXX Care enough to make sure this call does not happen if the magic
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# number is bad?
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source_timestamp = self.source_mtime(fullname)
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# Try to use bytecode if it is available.
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bytecode_path = self.bytecode_path(fullname)
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if bytecode_path:
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data = self.get_data(bytecode_path)
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try:
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magic = data[:4]
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if len(magic) < 4:
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raise ImportError("bad magic number in {}".format(fullname))
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raw_timestamp = data[4:8]
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if len(raw_timestamp) < 4:
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raise EOFError("bad timestamp in {}".format(fullname))
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pyc_timestamp = marshal._r_long(raw_timestamp)
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bytecode = data[8:]
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# Verify that the magic number is valid.
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if imp.get_magic() != magic:
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raise ImportError("bad magic number in {}".format(fullname))
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# Verify that the bytecode is not stale (only matters when
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# there is source to fall back on.
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if source_timestamp:
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if pyc_timestamp < source_timestamp:
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raise ImportError("bytecode is stale")
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except (ImportError, EOFError):
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# If source is available give it a shot.
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if source_timestamp is not None:
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pass
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else:
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raise
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else:
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# Bytecode seems fine, so try to use it.
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# XXX If the bytecode is ill-formed, would it be beneficial to
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# try for using source if available and issue a warning?
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return marshal.loads(bytecode)
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elif source_timestamp is None:
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raise ImportError("no source or bytecode available to create code "
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"object for {0!r}".format(fullname))
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# Use the source.
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code_object = super().get_code(fullname)
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# Generate bytecode and write it out.
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if not sys.dont_write_bytecode:
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data = bytearray(imp.get_magic())
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data.extend(marshal._w_long(source_timestamp))
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data.extend(marshal.dumps(code_object))
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self.write_bytecode(fullname, data)
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return code_object
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class _PyFileLoader(PyLoader):
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"""Load a Python source file."""
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def __init__(self, name, path, is_pkg):
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self._name = name
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self._is_pkg = is_pkg
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# Figure out the base path based on whether it was source or bytecode
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# that was found.
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try:
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self._base_path = _path_without_ext(path, imp.PY_SOURCE)
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except ValueError:
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self._base_path = _path_without_ext(path, imp.PY_COMPILED)
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def _find_path(self, ext_type):
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"""Find a path from the base path and the specified extension type that
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exists, returning None if one is not found."""
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for suffix in _suffix_list(ext_type):
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path = self._base_path + suffix
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if _path_exists(path):
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return path
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else:
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return None
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@_check_name
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def source_path(self, fullname):
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"""Return the path to an existing source file for the module, or None
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if one cannot be found."""
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# Not a property so that it is easy to override.
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return self._find_path(imp.PY_SOURCE)
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def get_data(self, path):
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"""Return the data from path as raw bytes."""
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return _io.FileIO(path, 'r').read() # Assuming bytes.
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@_check_name
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def is_package(self, fullname):
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"""Return a boolean based on whether the module is a package.
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Raises ImportError (like get_source) if the loader cannot handle the
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package.
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"""
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return self._is_pkg
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class _PyPycFileLoader(PyPycLoader, _PyFileLoader):
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"""Load a module from a source or bytecode file."""
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def _find_path(self, ext_type):
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"""Return PEP 3147 path if ext_type is PY_COMPILED, otherwise
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super()._find_path() is called."""
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if ext_type == imp.PY_COMPILED:
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# We don't really care what the extension on self._base_path is,
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# as long as it has exactly one dot.
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source_path = self._base_path + '.py'
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pycache_path = imp.cache_from_source(source_path)
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legacy_path = self._base_path + '.pyc'
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# The rule is: if the source file exists, then Python always uses
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# the __pycache__/foo.<tag>.pyc file. If the source file does not
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# exist, then Python uses the legacy path.
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pyc_path = (pycache_path
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if _path_exists(source_path)
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else legacy_path)
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return (pyc_path if _path_exists(pyc_path) else None)
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return super()._find_path(ext_type)
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@_check_name
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def source_mtime(self, name):
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"""Return the modification time of the source for the specified
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module."""
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source_path = self.source_path(name)
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if not source_path:
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return None
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return int(_os.stat(source_path).st_mtime)
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|
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@_check_name
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def bytecode_path(self, fullname):
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"""Return the path to a bytecode file, or None if one does not
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exist."""
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# Not a property for easy overriding.
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return self._find_path(imp.PY_COMPILED)
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|
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@_check_name
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def write_bytecode(self, name, data):
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"""Write out 'data' for the specified module, returning a boolean
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signifying if the write-out actually occurred.
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Raises ImportError (just like get_source) if the specified module
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cannot be handled by the loader.
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"""
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bytecode_path = self.bytecode_path(name)
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if not bytecode_path:
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source_path = self.source_path(name)
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bytecode_path = imp.cache_from_source(source_path)
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# Ensure that the __pycache__ directory exists. We can't use
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# os.path.dirname() here.
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|
dirname, sep, basename = bytecode_path.rpartition(path_sep)
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|
try:
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|
_os.mkdir(dirname)
|
|
except OSError as error:
|
|
if error.errno != errno.EEXIST:
|
|
raise
|
|
try:
|
|
# Assuming bytes.
|
|
with _closing(_io.FileIO(bytecode_path, 'w')) as bytecode_file:
|
|
bytecode_file.write(data)
|
|
return True
|
|
except IOError as exc:
|
|
if exc.errno == errno.EACCES:
|
|
return False
|
|
else:
|
|
raise
|
|
|
|
|
|
class _ExtensionFileLoader:
|
|
|
|
"""Loader for extension modules.
|
|
|
|
The constructor is designed to work with FileFinder.
|
|
|
|
"""
|
|
|
|
def __init__(self, name, path, is_pkg):
|
|
"""Initialize the loader.
|
|
|
|
If is_pkg is True then an exception is raised as extension modules
|
|
cannot be the __init__ module for an extension module.
|
|
|
|
"""
|
|
self._name = name
|
|
self._path = path
|
|
if is_pkg:
|
|
raise ValueError("extension modules cannot be packages")
|
|
|
|
@_check_name
|
|
@set_package
|
|
@set_loader
|
|
def load_module(self, fullname):
|
|
"""Load an extension module."""
|
|
is_reload = fullname in sys.modules
|
|
try:
|
|
return imp.load_dynamic(fullname, self._path)
|
|
except:
|
|
if not is_reload and fullname in sys.modules:
|
|
del sys.modules[fullname]
|
|
raise
|
|
|
|
@_check_name
|
|
def is_package(self, fullname):
|
|
"""Return False as an extension module can never be a package."""
|
|
return False
|
|
|
|
@_check_name
|
|
def get_code(self, fullname):
|
|
"""Return None as an extension module cannot create a code object."""
|
|
return None
|
|
|
|
@_check_name
|
|
def get_source(self, fullname):
|
|
"""Return None as extension modules have no source code."""
|
|
return None
|
|
|
|
|
|
# Finders #####################################################################
|
|
|
|
class PathFinder:
|
|
|
|
"""Meta path finder for sys.(path|path_hooks|path_importer_cache)."""
|
|
|
|
@classmethod
|
|
def _path_hooks(cls, path, hooks=None):
|
|
"""Search sequence of hooks for a finder for 'path'.
|
|
|
|
If 'hooks' is false then use sys.path_hooks.
|
|
|
|
"""
|
|
if not hooks:
|
|
hooks = sys.path_hooks
|
|
for hook in hooks:
|
|
try:
|
|
return hook(path)
|
|
except ImportError:
|
|
continue
|
|
else:
|
|
raise ImportError("no path hook found for {0}".format(path))
|
|
|
|
@classmethod
|
|
def _path_importer_cache(cls, path, default=None):
|
|
"""Get the finder for the path from sys.path_importer_cache.
|
|
|
|
If the path is not in the cache, find the appropriate finder and cache
|
|
it. If None is cached, get the default finder and cache that
|
|
(if applicable).
|
|
|
|
Because of NullImporter, some finder should be returned. The only
|
|
explicit fail case is if None is cached but the path cannot be used for
|
|
the default hook, for which ImportError is raised.
|
|
|
|
"""
|
|
try:
|
|
finder = sys.path_importer_cache[path]
|
|
except KeyError:
|
|
finder = cls._path_hooks(path)
|
|
sys.path_importer_cache[path] = finder
|
|
else:
|
|
if finder is None and default:
|
|
# Raises ImportError on failure.
|
|
finder = default(path)
|
|
sys.path_importer_cache[path] = finder
|
|
return finder
|
|
|
|
@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."""
|
|
if not path:
|
|
path = sys.path
|
|
for entry in path:
|
|
try:
|
|
finder = cls._path_importer_cache(entry)
|
|
except ImportError:
|
|
continue
|
|
if finder:
|
|
loader = finder.find_module(fullname)
|
|
if loader:
|
|
return loader
|
|
else:
|
|
return None
|
|
|
|
|
|
class _ChainedFinder:
|
|
|
|
"""Finder that sequentially calls other finders."""
|
|
|
|
def __init__(self, *finders):
|
|
self._finders = finders
|
|
|
|
def find_module(self, fullname, path=None):
|
|
for finder in self._finders:
|
|
result = finder.find_module(fullname, path)
|
|
if result:
|
|
return result
|
|
else:
|
|
return None
|
|
|
|
|
|
class _FileFinder:
|
|
|
|
"""Base class for file finders.
|
|
|
|
Subclasses are expected to define the following attributes:
|
|
|
|
* _suffixes
|
|
Sequence of file suffixes whose order will be followed.
|
|
|
|
* _possible_package
|
|
True if importer should check for packages.
|
|
|
|
* _loader
|
|
A callable that takes the module name, a file path, and whether
|
|
the path points to a package and returns a loader for the module
|
|
found at that path.
|
|
|
|
"""
|
|
|
|
def __init__(self, path_entry):
|
|
"""Initialize an importer for the passed-in sys.path entry (which is
|
|
assumed to have already been verified as an existing directory).
|
|
|
|
Can be used as an entry on sys.path_hook.
|
|
|
|
"""
|
|
absolute_path = _path_absolute(path_entry)
|
|
if not _path_isdir(absolute_path):
|
|
raise ImportError("only directories are supported")
|
|
self._path_entry = absolute_path
|
|
|
|
def find_module(self, fullname, path=None):
|
|
tail_module = fullname.rpartition('.')[2]
|
|
package_directory = None
|
|
if self._possible_package:
|
|
for ext in self._suffixes:
|
|
package_directory = _path_join(self._path_entry, tail_module)
|
|
init_filename = '__init__' + ext
|
|
package_init = _path_join(package_directory, init_filename)
|
|
if (_path_isfile(package_init) and
|
|
_case_ok(self._path_entry, tail_module) and
|
|
_case_ok(package_directory, init_filename)):
|
|
return self._loader(fullname, package_init, True)
|
|
for ext in self._suffixes:
|
|
file_name = tail_module + ext
|
|
file_path = _path_join(self._path_entry, file_name)
|
|
if (_path_isfile(file_path) and
|
|
_case_ok(self._path_entry, file_name)):
|
|
return self._loader(fullname, file_path, False)
|
|
else:
|
|
# Raise a warning if it matches a directory w/o an __init__ file.
|
|
if (package_directory is not None and
|
|
_path_isdir(package_directory) and
|
|
_case_ok(self._path_entry, tail_module)):
|
|
_warnings.warn("Not importing directory %s: missing __init__"
|
|
% package_directory, ImportWarning)
|
|
return None
|
|
|
|
|
|
class _PyFileFinder(_FileFinder):
|
|
|
|
"""Importer for source/bytecode files."""
|
|
|
|
_possible_package = True
|
|
_loader = _PyFileLoader
|
|
|
|
def __init__(self, path_entry):
|
|
# Lack of imp during class creation means _suffixes is set here.
|
|
# Make sure that Python source files are listed first! Needed for an
|
|
# optimization by the loader.
|
|
self._suffixes = _suffix_list(imp.PY_SOURCE)
|
|
super().__init__(path_entry)
|
|
|
|
|
|
class _PyPycFileFinder(_PyFileFinder):
|
|
|
|
"""Finder for source and bytecode files."""
|
|
|
|
_loader = _PyPycFileLoader
|
|
|
|
def __init__(self, path_entry):
|
|
super().__init__(path_entry)
|
|
self._suffixes += _suffix_list(imp.PY_COMPILED)
|
|
|
|
|
|
|
|
|
|
class _ExtensionFileFinder(_FileFinder):
|
|
|
|
"""Importer for extension files."""
|
|
|
|
_possible_package = False
|
|
_loader = _ExtensionFileLoader
|
|
|
|
def __init__(self, path_entry):
|
|
# Assigning to _suffixes here instead of at the class level because
|
|
# imp is not imported at the time of class creation.
|
|
self._suffixes = _suffix_list(imp.C_EXTENSION)
|
|
super().__init__(path_entry)
|
|
|
|
|
|
# Import itself ###############################################################
|
|
|
|
def _chained_path_hook(*path_hooks):
|
|
"""Create a closure which sequentially checks path hooks to see which ones
|
|
(if any) can work with a path."""
|
|
def path_hook(entry):
|
|
"""Check to see if 'entry' matches any of the enclosed path hooks."""
|
|
finders = []
|
|
for hook in path_hooks:
|
|
try:
|
|
finder = hook(entry)
|
|
except ImportError:
|
|
continue
|
|
else:
|
|
finders.append(finder)
|
|
if not finders:
|
|
raise ImportError("no finder found")
|
|
else:
|
|
return _ChainedFinder(*finders)
|
|
|
|
return path_hook
|
|
|
|
|
|
_DEFAULT_PATH_HOOK = _chained_path_hook(_ExtensionFileFinder, _PyPycFileFinder)
|
|
|
|
class _DefaultPathFinder(PathFinder):
|
|
|
|
"""Subclass of PathFinder that implements implicit semantics for
|
|
__import__."""
|
|
|
|
@classmethod
|
|
def _path_hooks(cls, path):
|
|
"""Search sys.path_hooks as well as implicit path hooks."""
|
|
try:
|
|
return super()._path_hooks(path)
|
|
except ImportError:
|
|
implicit_hooks = [_DEFAULT_PATH_HOOK, imp.NullImporter]
|
|
return super()._path_hooks(path, implicit_hooks)
|
|
|
|
@classmethod
|
|
def _path_importer_cache(cls, path):
|
|
"""Use the default path hook when None is stored in
|
|
sys.path_importer_cache."""
|
|
return super()._path_importer_cache(path, _DEFAULT_PATH_HOOK)
|
|
|
|
|
|
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()
|
|
|
|
|
|
_IMPLICIT_META_PATH = [BuiltinImporter, FrozenImporter, _DefaultPathFinder]
|
|
|
|
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 settting __package__ if
|
|
the loader did not.
|
|
|
|
"""
|
|
if package:
|
|
if not hasattr(package, 'rindex'):
|
|
raise ValueError("__package__ not set to a string")
|
|
elif package not in sys.modules:
|
|
msg = ("Parent module {0!r} not loaded, cannot perform relative "
|
|
"import")
|
|
raise SystemError(msg.format(package))
|
|
if not name and level == 0:
|
|
raise ValueError("Empty module name")
|
|
if level > 0:
|
|
dot = len(package)
|
|
for x in range(level, 1, -1):
|
|
try:
|
|
dot = package.rindex('.', 0, dot)
|
|
except ValueError:
|
|
raise ValueError("attempted relative import beyond "
|
|
"top-level package")
|
|
if name:
|
|
name = "{0}.{1}".format(package[:dot], name)
|
|
else:
|
|
name = package[:dot]
|
|
with _ImportLockContext():
|
|
try:
|
|
module = sys.modules[name]
|
|
if module is None:
|
|
message = ("import of {} halted; "
|
|
"None in sys.modules".format(name))
|
|
raise ImportError(message)
|
|
return module
|
|
except KeyError:
|
|
pass
|
|
parent = name.rpartition('.')[0]
|
|
path = None
|
|
if parent:
|
|
if parent not in sys.modules:
|
|
_gcd_import(parent)
|
|
# Backwards-compatibility; be nicer to skip the dict lookup.
|
|
parent_module = sys.modules[parent]
|
|
try:
|
|
path = parent_module.__path__
|
|
except AttributeError:
|
|
raise ImportError("no module named {}; "
|
|
"{} is not a package".format(name, parent))
|
|
meta_path = sys.meta_path + _IMPLICIT_META_PATH
|
|
for finder in meta_path:
|
|
loader = finder.find_module(name, path)
|
|
if loader is not None:
|
|
loader.load_module(name)
|
|
break
|
|
else:
|
|
raise ImportError("No module named {0}".format(name))
|
|
# Backwards-compatibility; be nicer to skip the dict lookup.
|
|
module = sys.modules[name]
|
|
if parent:
|
|
# Set the module as an attribute on its parent.
|
|
setattr(parent_module, name.rpartition('.')[2], module)
|
|
# Set __package__ if the loader did not.
|
|
if not hasattr(module, '__package__') or module.__package__ is None:
|
|
# Watch out for what comes out of sys.modules to not be a module,
|
|
# e.g. an int.
|
|
try:
|
|
module.__package__ = module.__name__
|
|
if not hasattr(module, '__path__'):
|
|
module.__package__ = module.__package__.rpartition('.')[0]
|
|
except AttributeError:
|
|
pass
|
|
return module
|
|
|
|
|
|
def __import__(name, globals={}, locals={}, 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 <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 not hasattr(name, 'rpartition'):
|
|
raise TypeError("module name must be str, not {}".format(type(name)))
|
|
if level == 0:
|
|
module = _gcd_import(name)
|
|
else:
|
|
# __package__ is not guaranteed to be defined or could be set to None
|
|
# to represent that it's proper value is unknown
|
|
package = globals.get('__package__')
|
|
if package is None:
|
|
package = globals['__name__']
|
|
if '__path__' not in globals:
|
|
package = package.rpartition('.')[0]
|
|
module = _gcd_import(name, package, level)
|
|
# The hell that is fromlist ...
|
|
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 sys.modules[name.partition('.')[0]]
|
|
elif not name:
|
|
return module
|
|
else:
|
|
cut_off = len(name) - len(name.partition('.')[0])
|
|
return sys.modules[module.__name__[:-cut_off]]
|
|
else:
|
|
# If a package was imported, try to import stuff from fromlist.
|
|
if hasattr(module, '__path__'):
|
|
if '*' in fromlist and hasattr(module, '__all__'):
|
|
fromlist = list(fromlist)
|
|
fromlist.remove('*')
|
|
fromlist.extend(module.__all__)
|
|
for x in (y for y in fromlist if not hasattr(module,y)):
|
|
try:
|
|
_gcd_import('{0}.{1}'.format(module.__name__, x))
|
|
except ImportError:
|
|
pass
|
|
return module
|