diff options
| author | Eric Snow <ericsnowcurrently@gmail.com> | 2013-11-22 16:05:39 (GMT) |
|---|---|---|
| committer | Eric Snow <ericsnowcurrently@gmail.com> | 2013-11-22 16:05:39 (GMT) |
| commit | b523f8433a8982e10eb41a3e2b37ee0e6d6a6e00 (patch) | |
| tree | b38661db4903b7edc4042e7562b32720dd3687bf /Lib/importlib/abc.py | |
| parent | 9e6097ebe7bb99a4a22b949ef4b1563b21ad7166 (diff) | |
| download | cpython-b523f8433a8982e10eb41a3e2b37ee0e6d6a6e00.zip cpython-b523f8433a8982e10eb41a3e2b37ee0e6d6a6e00.tar.gz cpython-b523f8433a8982e10eb41a3e2b37ee0e6d6a6e00.tar.bz2 | |
Implement PEP 451 (ModuleSpec).
Diffstat (limited to 'Lib/importlib/abc.py')
| -rw-r--r-- | Lib/importlib/abc.py | 102 |
1 files changed, 53 insertions, 49 deletions
diff --git a/Lib/importlib/abc.py b/Lib/importlib/abc.py index 01de67d..3995ff2 100644 --- a/Lib/importlib/abc.py +++ b/Lib/importlib/abc.py @@ -40,12 +40,18 @@ class MetaPathFinder(Finder): """Abstract base class for import finders on sys.meta_path.""" - @abc.abstractmethod + # We don't define find_spec() here since that would break + # hasattr checks we do to support backward compatibility. + + # XXX Deprecate def find_module(self, fullname, path): - """Abstract method which, when implemented, should find a module. - The fullname is a str and the path is a list of strings or None. - Returns a Loader object or None. + """Return a loader for the module. + + If no module is found, return None. The fullname is a str and + the path is a list of strings or None. + """ + return None def invalidate_caches(self): """An optional method for clearing the finder's cache, if any. @@ -60,17 +66,25 @@ class PathEntryFinder(Finder): """Abstract base class for path entry finders used by PathFinder.""" - @abc.abstractmethod + # We don't define find_spec() here since that would break + # hasattr checks we do to support backward compatibility. + + # XXX Deprecate. def find_loader(self, fullname): - """Abstract method which, when implemented, returns a module loader or - a possible part of a namespace. - The fullname is a str. Returns a 2-tuple of (Loader, portion) where - portion is a sequence of file system locations contributing to part of - a namespace package. The sequence may be empty and the loader may be - None. + """Return (loader, namespace portion) for the path entry. + + The fullname is a str. The namespace portion is a sequence of + path entries contributing to part of a namespace package. The + sequence may be empty. If loader is not None, the portion will + be ignored. + + The portion will be discarded if another path entry finder + locates the module as a normal module or package. + """ return None, [] + # XXX Deprecate. find_module = _bootstrap._find_module_shim def invalidate_caches(self): @@ -83,35 +97,47 @@ _register(PathEntryFinder, machinery.FileFinder) class Loader(metaclass=abc.ABCMeta): - """Abstract base class for import loaders. + """Abstract base class for import loaders.""" - The optional method module_repr(module) may be defined to provide a - repr for a module when appropriate (see PEP 420). The __repr__() method on - the module type will use the method as appropriate. + def create_module(self, spec): + """Return a module to initialize and into which to load. - """ + This method should raise ImportError if anything prevents it + from creating a new module. It may return None to indicate + that the spec should create the new module. - @abc.abstractmethod + create_module() is optional. + + """ + # By default, defer to _SpecMethods.create() for the new module. + return None + + # We don't define exec_module() here since that would break + # hasattr checks we do to support backward compatibility. + + # XXX Deprecate. def load_module(self, fullname): - """Abstract method which when implemented should load a module. - The fullname is a str. + """Return the loaded module. + + The module must be added to sys.modules and have import-related + attributes set properly. The fullname is a str. ImportError is raised on failure. + """ raise ImportError + # XXX Deprecate. def module_repr(self, module): """Return a module's repr. Used by the module type when the method does not raise NotImplementedError. + """ + # The exception will cause ModuleType.__repr__ to ignore this method. raise NotImplementedError - def init_module_attrs(self, module): - """Set the module's __loader__ attribute.""" - module.__loader__ = self - class ResourceLoader(Loader): @@ -138,12 +164,11 @@ class InspectLoader(Loader): """ - @abc.abstractmethod def is_package(self, fullname): - """Abstract method which when implemented should return whether the + """Optional method which when implemented should return whether the module is a package. The fullname is a str. Returns a bool. - Raises ImportError is the module cannot be found. + Raises ImportError if the module cannot be found. """ raise ImportError @@ -176,19 +201,10 @@ class InspectLoader(Loader): argument should be where the data was retrieved (when applicable).""" return compile(data, path, 'exec', dont_inherit=True) - def init_module_attrs(self, module): - """Initialize the __loader__ and __package__ attributes of the module. - - The name of the module is gleaned from module.__name__. The __package__ - attribute is set based on self.is_package(). - """ - super().init_module_attrs(module) - _bootstrap._init_package_attrs(self, module) - + exec_module = _bootstrap._LoaderBasics.exec_module load_module = _bootstrap._LoaderBasics.load_module -_register(InspectLoader, machinery.BuiltinImporter, machinery.FrozenImporter, - _bootstrap.NamespaceLoader) +_register(InspectLoader, machinery.BuiltinImporter, machinery.FrozenImporter) class ExecutionLoader(InspectLoader): @@ -225,18 +241,6 @@ class ExecutionLoader(InspectLoader): else: return self.source_to_code(source, path) - def init_module_attrs(self, module): - """Initialize the module's attributes. - - It is assumed that the module's name has been set on module.__name__. - It is also assumed that any path returned by self.get_filename() uses - (one of) the operating system's path separator(s) to separate filenames - from directories in order to set __path__ intelligently. - InspectLoader.init_module_attrs() sets __loader__ and __package__. - """ - super().init_module_attrs(module) - _bootstrap._init_file_attrs(self, module) - _register(ExecutionLoader, machinery.ExtensionFileLoader) |