Introduce importlib.abc. The module contains various ABCs related to imports
(mostly stuff specified by PEP 302). There are two ABCs, PyLoader and
PyPycLoader, which help with implementing source and source/bytecode loaders by
implementing load_module in terms of other methods. This removes a lot of
gritty details loaders typically have to worry about.
diff --git a/Lib/importlib/abc.py b/Lib/importlib/abc.py
new file mode 100644
index 0000000..2ecb821
--- /dev/null
+++ b/Lib/importlib/abc.py
@@ -0,0 +1,110 @@
+"""Abstract base classes related to import."""
+from . import _bootstrap
+from . import machinery
+import abc
+import types
+
+
+class Loader(metaclass=abc.ABCMeta):
+
+ """Abstract base class for import loaders.
+
+ See PEP 302 for details.
+
+ """
+
+ def load_module(self, fullname:str) -> types.ModuleType:
+ raise NotImplementedError
+
+Loader.register(machinery.BuiltinImporter)
+Loader.register(machinery.FrozenImporter)
+
+
+class Finder(metaclass=abc.ABCMeta):
+
+ """Abstract base class for import finders.
+
+ See PEP 302 for details.
+
+ """
+
+ @abc.abstractmethod
+ def find_module(self, fullname:str, path:[str]=None) -> Loader:
+ raise NotImplementedError
+
+Finder.register(machinery.BuiltinImporter)
+Finder.register(machinery.FrozenImporter)
+Finder.register(machinery.PathFinder)
+
+
+class Importer(Finder, Loader):
+
+ """Abstract base class for importers."""
+
+
+
+class ResourceLoader(Loader):
+
+ """Abstract base class for loaders which can return data from the back-end
+ storage.
+
+ This ABC represents one of the optional protocols specified by PEP 302.
+
+ """
+
+ @abc.abstractmethod
+ def get_data(self, path:str) -> bytes:
+ raise NotImplementedError
+
+
+class InspectLoader(Loader):
+
+ """Abstract base class for loaders which supports introspection.
+
+ This ABC represents one of the optional protocols specified by PEP 302.
+
+ """
+
+ @abc.abstractmethod
+ def is_package(self, fullname:str) -> bool:
+ return NotImplementedError
+
+ @abc.abstractmethod
+ def get_code(self, fullname:str) -> types.CodeType:
+ return NotImplementedError
+
+ @abc.abstractmethod
+ def get_source(self, fullname:str) -> str:
+ return NotImplementedError
+
+
+class PyLoader(_bootstrap.PyLoader, InspectLoader):
+
+ """Abstract base class that implements the core parts needed to load Python
+ source code."""
+
+ # load_module and get_code are implemented.
+
+ @abc.abstractmethod
+ def source_path(self, fullname:str) -> object:
+ raise NotImplementedError
+
+
+class PyPycLoader(_bootstrap.PyPycLoader, PyLoader):
+
+ """Abstract base class that implements the core parts needed to load Python
+ source and bytecode."""
+
+ # Implements load_module and get_code.
+
+ @abc.abstractmethod
+ def source_mtime(self, fullname:str) -> int:
+ raise NotImplementedError
+
+ @abc.abstractmethod
+ def bytecode_path(self, fullname:str) -> object:
+ raise NotImplementedError
+
+ @abc.abstractmethod
+ def write_bytecode(self, fullname:str, bytecode:bytes):
+ raise NotImplementedError