diff options
Diffstat (limited to 'Lib/importlib/__init__.py')
| -rw-r--r-- | Lib/importlib/__init__.py | 178 |
1 files changed, 20 insertions, 158 deletions
diff --git a/Lib/importlib/__init__.py b/Lib/importlib/__init__.py index 0c73c50..ad31a1a 100644 --- a/Lib/importlib/__init__.py +++ b/Lib/importlib/__init__.py @@ -1,109 +1,20 @@ -"""A pure Python implementation of import.""" -__all__ = ['__import__', 'import_module', 'invalidate_caches', 'reload'] - -# Bootstrap help ##################################################### - -# Until bootstrapping is complete, DO NOT import any modules that attempt -# to import importlib._bootstrap (directly or indirectly). Since this -# partially initialised package would be present in sys.modules, those -# modules would get an uninitialised copy of the source version, instead -# of a fully initialised version (either the frozen one or the one -# initialised below if the frozen one is not available). -import _imp # Just the builtin component, NOT the full Python module +"""Backport of importlib.import_module from 3.x.""" +# While not critical (and in no way guaranteed!), it would be nice to keep this +# code compatible with Python 2.3. import sys -try: - import _frozen_importlib as _bootstrap -except ImportError: - from . import _bootstrap - _bootstrap._setup(sys, _imp) -else: - # importlib._bootstrap is the built-in import, ensure we don't create - # a second copy of the module. - _bootstrap.__name__ = 'importlib._bootstrap' - _bootstrap.__package__ = 'importlib' - try: - _bootstrap.__file__ = __file__.replace('__init__.py', '_bootstrap.py') - except NameError: - # __file__ is not guaranteed to be defined, e.g. if this code gets - # frozen by a tool like cx_Freeze. - pass - sys.modules['importlib._bootstrap'] = _bootstrap - -try: - import _frozen_importlib_external as _bootstrap_external -except ImportError: - from . import _bootstrap_external - _bootstrap_external._setup(_bootstrap) - _bootstrap._bootstrap_external = _bootstrap_external -else: - _bootstrap_external.__name__ = 'importlib._bootstrap_external' - _bootstrap_external.__package__ = 'importlib' - try: - _bootstrap_external.__file__ = __file__.replace('__init__.py', '_bootstrap_external.py') - except NameError: - # __file__ is not guaranteed to be defined, e.g. if this code gets - # frozen by a tool like cx_Freeze. - pass - sys.modules['importlib._bootstrap_external'] = _bootstrap_external - -# To simplify imports in test code -_pack_uint32 = _bootstrap_external._pack_uint32 -_unpack_uint32 = _bootstrap_external._unpack_uint32 - -# Fully bootstrapped at this point, import whatever you like, circular -# dependencies and startup overhead minimisation permitting :) - -import types -import warnings - - -# Public API ######################################################### - -from ._bootstrap import __import__ - - -def invalidate_caches(): - """Call the invalidate_caches() method on all meta path finders stored in - sys.meta_path (where implemented).""" - for finder in sys.meta_path: - if hasattr(finder, 'invalidate_caches'): - finder.invalidate_caches() - - -def find_loader(name, path=None): - """Return the loader for the specified module. - - This is a backward-compatible wrapper around find_spec(). - - This function is deprecated in favor of importlib.util.find_spec(). - - """ - warnings.warn('Deprecated since Python 3.4. ' - 'Use importlib.util.find_spec() instead.', - DeprecationWarning, stacklevel=2) - try: - loader = sys.modules[name].__loader__ - if loader is None: - raise ValueError('{}.__loader__ is None'.format(name)) - else: - return loader - except KeyError: - pass - except AttributeError: - raise ValueError('{}.__loader__ is not set'.format(name)) from None - - spec = _bootstrap._find_spec(name, path) - # We won't worry about malformed specs (missing attributes). - if spec is None: - return None - if spec.loader is None: - if spec.submodule_search_locations is None: - raise ImportError('spec for {} missing loader'.format(name), - name=name) - raise ImportError('namespace packages do not have loaders', - name=name) - return spec.loader +def _resolve_name(name, package, level): + """Return the absolute name of the module to be imported.""" + if not hasattr(package, 'rindex'): + raise ValueError("'package' not set to a string") + dot = len(package) + for x in xrange(level, 1, -1): + try: + dot = package.rindex('.', 0, dot) + except ValueError: + raise ValueError("attempted relative import beyond top-level " + "package") + return "%s.%s" % (package[:dot], name) def import_module(name, package=None): @@ -114,63 +25,14 @@ def import_module(name, package=None): relative import to an absolute import. """ - level = 0 if name.startswith('.'): if not package: - msg = ("the 'package' argument is required to perform a relative " - "import for {!r}") - raise TypeError(msg.format(name)) + raise TypeError("relative imports require the 'package' argument") + level = 0 for character in name: if character != '.': break level += 1 - return _bootstrap._gcd_import(name[level:], package, level) - - -_RELOADING = {} - - -def reload(module): - """Reload the module and return it. - - The module must have been successfully imported before. - - """ - if not module or not isinstance(module, types.ModuleType): - raise TypeError("reload() argument must be a module") - try: - name = module.__spec__.name - except AttributeError: - name = module.__name__ - - if sys.modules.get(name) is not module: - msg = "module {} not in sys.modules" - raise ImportError(msg.format(name), name=name) - if name in _RELOADING: - return _RELOADING[name] - _RELOADING[name] = module - try: - parent_name = name.rpartition('.')[0] - if parent_name: - try: - parent = sys.modules[parent_name] - except KeyError: - msg = "parent {!r} not in sys.modules" - raise ImportError(msg.format(parent_name), - name=parent_name) from None - else: - pkgpath = parent.__path__ - else: - pkgpath = None - target = module - spec = module.__spec__ = _bootstrap._find_spec(name, pkgpath, target) - if spec is None: - raise ModuleNotFoundError(f"spec not found for the module {name!r}", name=name) - _bootstrap._exec(spec, module) - # The module may have replaced itself in sys.modules! - return sys.modules[name] - finally: - try: - del _RELOADING[name] - except KeyError: - pass + name = _resolve_name(name[level:], package, level) + __import__(name) + return sys.modules[name] |