| """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. |
| |
| """ |
| |
| # Injected modules are '_warnings', 'imp', 'sys', 'marshal', 'errno', '_io', |
| # and '_os' (a.k.a. 'posix', 'nt' or 'os2'). |
| # Injected attribute is path_sep. |
| # |
| # 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 ###################################################### |
| |
| # XXX Could also expose Modules/getpath.c:joinpath() |
| def _path_join(*args): |
| """Replacement for os.path.join.""" |
| return path_sep.join(x[:-len(path_sep)] if x.endswith(path_sep) else x |
| for x in args) |
| |
| |
| def _path_exists(path): |
| """Replacement for os.path.exists.""" |
| try: |
| _os.stat(path) |
| except OSError: |
| return False |
| else: |
| return True |
| |
| |
| def _path_is_mode_type(path, mode): |
| """Test whether the path is the specified mode type.""" |
| try: |
| stat_info = _os.stat(path) |
| except OSError: |
| return False |
| return (stat_info.st_mode & 0o170000) == mode |
| |
| |
| # XXX Could also expose Modules/getpath.c:isfile() |
| def _path_isfile(path): |
| """Replacement for os.path.isfile.""" |
| return _path_is_mode_type(path, 0o100000) |
| |
| |
| # XXX Could also expose Modules/getpath.c:isdir() |
| def _path_isdir(path): |
| """Replacement for os.path.isdir.""" |
| return _path_is_mode_type(path, 0o040000) |
| |
| |
| def _path_without_ext(path, ext_type): |
| """Replacement for os.path.splitext()[0].""" |
| for suffix in _suffix_list(ext_type): |
| if path.endswith(suffix): |
| return path[:-len(suffix)] |
| else: |
| raise ValueError("path is not of the specified type") |
| |
| |
| def _path_absolute(path): |
| """Replacement for os.path.abspath.""" |
| if not path: |
| path = _os.getcwd() |
| try: |
| return _os._getfullpathname(path) |
| except AttributeError: |
| if path.startswith('/'): |
| return path |
| else: |
| return _path_join(_os.getcwd(), path) |
| |
| |
| class _closing: |
| |
| """Simple replacement for contextlib.closing.""" |
| |
| def __init__(self, obj): |
| self.obj = obj |
| |
| def __enter__(self): |
| return self.obj |
| |
| def __exit__(self, *args): |
| self.obj.close() |
| |
| |
| def _wrap(new, old): |
| """Simple substitute for functools.wraps.""" |
| for replace in ['__module__', '__name__', '__doc__']: |
| setattr(new, replace, getattr(old, replace)) |
| new.__dict__.update(old.__dict__) |
| |
| |
| # Finder/loader utility code ################################################## |
| |
| def set_package(fxn): |
| """Set __package__ on the returned module.""" |
| def wrapper(*args, **kwargs): |
| module = fxn(*args, **kwargs) |
| if not hasattr(module, '__package__') or module.__package__ is None: |
| module.__package__ = module.__name__ |
| if not hasattr(module, '__path__'): |
| module.__package__ = module.__package__.rpartition('.')[0] |
| return module |
| _wrap(wrapper, fxn) |
| return wrapper |
| |
| |
| def set_loader(fxn): |
| """Set __loader__ on the returned module.""" |
| def wrapper(self, *args, **kwargs): |
| module = fxn(self, *args, **kwargs) |
| if not hasattr(module, '__loader__'): |
| module.__loader__ = self |
| return module |
| _wrap(wrapper, fxn) |
| return 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 which has __name__ set and is inserted |
| into sys.modules. 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. |
| |
| """ |
| def decorated(self, fullname): |
| module = sys.modules.get(fullname) |
| is_reload = bool(module) |
| 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 = imp.new_module(fullname) |
| sys.modules[fullname] = module |
| try: |
| return fxn(self, module) |
| except: |
| if not is_reload: |
| del sys.modules[fullname] |
| raise |
| _wrap(decorated, fxn) |
| return decorated |
| |
| |
| def _check_name(method): |
| """Decorator to verify that the module being requested matches the one the |
| loader can handle. |
| |
| The first argument (self) must define _name which the second argument is |
| comapred against. If the comparison fails then ImportError is raised. |
| |
| """ |
| def inner(self, name, *args, **kwargs): |
| if self._name != name: |
| raise ImportError("loader cannot handle %s" % name) |
| return method(self, name, *args, **kwargs) |
| _wrap(inner, method) |
| return inner |
| |
| |
| def _requires_builtin(fxn): |
| """Decorator to verify the named module is built-in.""" |
| def wrapper(self, fullname): |
| if fullname not in sys.builtin_module_names: |
| raise ImportError("{0} is not a built-in module".format(fullname)) |
| return fxn(self, fullname) |
| _wrap(wrapper, fxn) |
| return wrapper |
| |
| |
| def _requires_frozen(fxn): |
| """Decorator to verify the named module is frozen.""" |
| def wrapper(self, fullname): |
| if not imp.is_frozen(fullname): |
| raise ImportError("{0} is not a frozen module".format(fullname)) |
| return fxn(self, fullname) |
| _wrap(wrapper, fxn) |
| return wrapper |
| |
| |
| def _suffix_list(suffix_type): |
| """Return a list of file suffixes based on the imp file type.""" |
| return [suffix[0] for suffix in imp.get_suffixes() |
| if suffix[2] == suffix_type] |
| |
| |
| # 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. |
| |
| """ |
| |
| @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. |
| |
| """ |
| if path is not None: |
| return None |
| return cls if imp.is_builtin(fullname) else None |
| |
| @classmethod |
| @set_package |
| @set_loader |
| @_requires_builtin |
| def load_module(cls, fullname): |
| """Load a built-in module.""" |
| is_reload = fullname in sys.modules |
| try: |
| return imp.init_builtin(fullname) |
| except: |
| if not is_reload and fullname in sys.modules: |
| del sys.modules[fullname] |
| raise |
| |
| @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 None as built-in module are never packages.""" |
| return False |
| |
| |
| class FrozenImporter: |
| |
| """Meta path import for frozen modules. |
| |
| All methods are either class or static methods to avoid the need to |
| instantiate the class. |
| |
| """ |
| |
| @classmethod |
| def find_module(cls, fullname, path=None): |
| """Find a frozen module.""" |
| return cls if imp.is_frozen(fullname) else None |
| |
| @classmethod |
| @set_package |
| @set_loader |
| @_requires_frozen |
| def load_module(cls, fullname): |
| """Load a frozen module.""" |
| is_reload = fullname in sys.modules |
| try: |
| return imp.init_frozen(fullname) |
| except: |
| if not is_reload and fullname in sys.modules: |
| del sys.modules[fullname] |
| raise |
| |
| @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 if the frozen module is a package.""" |
| return imp.is_frozen_package(fullname) |
| |
| |
| class PyLoader: |
| |
| """Loader base class for Python source code. |
| |
| Subclasses need to implement the methods: |
| |
| - source_path |
| - get_data |
| - is_package |
| |
| """ |
| |
| @module_for_loader |
| def load_module(self, module): |
| """Initialize the module.""" |
| name = module.__name__ |
| code_object = self.get_code(module.__name__) |
| module.__file__ = self.get_filename(name) |
| if self.is_package(name): |
| module.__path__ = [module.__file__.rsplit(path_sep, 1)[0]] |
| module.__package__ = module.__name__ |
| if not hasattr(module, '__path__'): |
| module.__package__ = module.__package__.rpartition('.')[0] |
| module.__loader__ = self |
| exec(code_object, module.__dict__) |
| return module |
| |
| def get_filename(self, fullname): |
| """Return the path to the source file, else raise ImportError.""" |
| path = self.source_path(fullname) |
| if path is not None: |
| return path |
| else: |
| raise ImportError("no source path available for " |
| "{0!r}".format(fullname)) |
| |
| def get_code(self, fullname): |
| """Get a code object from source.""" |
| source_path = self.source_path(fullname) |
| if source_path is None: |
| message = "a source path must exist to load {0}".format(fullname) |
| raise ImportError(message) |
| source = self.get_data(source_path) |
| return compile(source, source_path, 'exec', dont_inherit=True) |
| |
| # Never use in implementing import! Imports code within the method. |
| def get_source(self, fullname): |
| """Return the source code for a module. |
| |
| self.source_path() and self.get_data() are used to implement this |
| method. |
| |
| """ |
| path = self.source_path(fullname) |
| if path is None: |
| return None |
| try: |
| source_bytes = self.get_data(path) |
| except IOError: |
| return ImportError("source not available through get_data()") |
| import io |
| import tokenize |
| encoding = tokenize.detect_encoding(io.BytesIO(source_bytes).readline) |
| return source_bytes.decode(encoding[0]) |
| |
| |
| class PyPycLoader(PyLoader): |
| |
| """Loader base class for Python source and bytecode. |
| |
| Requires implementing the methods needed for PyLoader as well as |
| source_mtime, bytecode_path, and write_bytecode. |
| |
| """ |
| |
| def get_filename(self, fullname): |
| """Return the source or bytecode file path.""" |
| path = self.source_path(fullname) |
| if path is not None: |
| return path |
| path = self.bytecode_path(fullname) |
| if path is not None: |
| return path |
| raise ImportError("no source or bytecode path available for " |
| "{0!r}".format(fullname)) |
| |
| def get_code(self, fullname): |
| """Get a code object from source or bytecode.""" |
| # XXX Care enough to make sure this call does not happen if the magic |
| # number is bad? |
| source_timestamp = self.source_mtime(fullname) |
| # Try to use bytecode if it is available. |
| bytecode_path = self.bytecode_path(fullname) |
| if bytecode_path: |
| data = self.get_data(bytecode_path) |
| try: |
| magic = data[:4] |
| if len(magic) < 4: |
| raise ImportError("bad magic number in {}".format(fullname)) |
| raw_timestamp = data[4:8] |
| if len(raw_timestamp) < 4: |
| raise EOFError("bad timestamp in {}".format(fullname)) |
| pyc_timestamp = marshal._r_long(raw_timestamp) |
| bytecode = data[8:] |
| # Verify that the magic number is valid. |
| if imp.get_magic() != magic: |
| raise ImportError("bad magic number in {}".format(fullname)) |
| # Verify that the bytecode is not stale (only matters when |
| # there is source to fall back on. |
| if source_timestamp: |
| if pyc_timestamp < source_timestamp: |
| raise ImportError("bytecode is stale") |
| except (ImportError, EOFError): |
| # If source is available give it a shot. |
| if source_timestamp is not None: |
| pass |
| else: |
| raise |
| else: |
| # Bytecode seems fine, so try to use it. |
| # XXX If the bytecode is ill-formed, would it be beneficial to |
| # try for using source if available and issue a warning? |
| return marshal.loads(bytecode) |
| elif source_timestamp is None: |
| raise ImportError("no source or bytecode available to create code " |
| "object for {0!r}".format(fullname)) |
| # Use the source. |
| code_object = super().get_code(fullname) |
| # Generate bytecode and write it out. |
| if not sys.dont_write_bytecode: |
| data = bytearray(imp.get_magic()) |
| data.extend(marshal._w_long(source_timestamp)) |
| data.extend(marshal.dumps(code_object)) |
| self.write_bytecode(fullname, data) |
| return code_object |
| |
| |
| class _PyFileLoader(PyLoader): |
| |
| """Load a Python source file.""" |
| |
| def __init__(self, name, path, is_pkg): |
| self._name = name |
| self._is_pkg = is_pkg |
| # Figure out the base path based on whether it was source or bytecode |
| # that was found. |
| try: |
| self._base_path = _path_without_ext(path, imp.PY_SOURCE) |
| except ValueError: |
| self._base_path = _path_without_ext(path, imp.PY_COMPILED) |
| |
| def _find_path(self, ext_type): |
| """Find a path from the base path and the specified extension type that |
| exists, returning None if one is not found.""" |
| for suffix in _suffix_list(ext_type): |
| path = self._base_path + suffix |
| if _path_exists(path): |
| return path |
| else: |
| return None |
| |
| @_check_name |
| def source_path(self, fullname): |
| """Return the path to an existing source file for the module, or None |
| if one cannot be found.""" |
| # Not a property so that it is easy to override. |
| return self._find_path(imp.PY_SOURCE) |
| |
| def get_data(self, path): |
| """Return the data from path as raw bytes.""" |
| return _io.FileIO(path, 'r').read() # Assuming bytes. |
| |
| @_check_name |
| def is_package(self, fullname): |
| """Return a boolean based on whether the module is a package. |
| |
| Raises ImportError (like get_source) if the loader cannot handle the |
| package. |
| |
| """ |
| return self._is_pkg |
| |
| |
| class _PyPycFileLoader(PyPycLoader, _PyFileLoader): |
| |
| """Load a module from a source or bytecode file.""" |
| |
| @_check_name |
| def source_mtime(self, name): |
| """Return the modification time of the source for the specified |
| module.""" |
| source_path = self.source_path(name) |
| if not source_path: |
| return None |
| return int(_os.stat(source_path).st_mtime) |
| |
| @_check_name |
| def bytecode_path(self, fullname): |
| """Return the path to a bytecode file, or None if one does not |
| exist.""" |
| # Not a property for easy overriding. |
| return self._find_path(imp.PY_COMPILED) |
| |
| @_check_name |
| def write_bytecode(self, name, data): |
| """Write out 'data' for the specified module, returning a boolean |
| signifying if the write-out actually occurred. |
| |
| Raises ImportError (just like get_source) if the specified module |
| cannot be handled by the loader. |
| |
| """ |
| bytecode_path = self.bytecode_path(name) |
| if not bytecode_path: |
| bytecode_path = self._base_path + _suffix_list(imp.PY_COMPILED)[0] |
| 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 |