Start implementing some typeshed details

jedi/plugins/__init__.py

@@ -34,6 +34,6 @@ class _PluginCallbacks(object):
 
 plugin_manager = _PluginManager([
     StdlibPlugin,
-    TypeshedPlugin,
     FlaskPlugin,
+    TypeshedPlugin,
 ])

jedi/plugins/typeshed.py

@@ -1,17 +1,119 @@
+import os
+import re
+
+from jedi._compatibility import FileNotFoundError
 from jedi.plugins.base import BasePlugin
+from jedi.evaluate.cache import evaluator_as_method_param_cache
 from jedi.evaluate.base_context import Context, ContextSet
+from jedi.evaluate.context import ModuleContext
+
+
+_TYPESHED_PATH = os.path.join(
+    os.path.dirname(os.path.dirname(__file__)),
+    'third_party',
+    'typeshed',
+)
+
+
+def _create_stub_map(directory):
+    """
+    Create a mapping of an importable name in Python to a stub file.
+    """
+    def generate():
+        try:
+            listed = os.listdir(directory)
+        except FileNotFoundError:
+            return
+
+        for entry in listed:
+            path = os.path.join(directory, entry)
+            if os.path.isdir(path):
+                init = os.path.join(path, '__init__.pyi')
+                if os.path.isfile(init):
+                    yield entry, init
+            elif entry.endswith('.pyi') and os.path.isfile(path):
+                name = entry.rstrip('.pyi')
+                yield name, path
+
+    # Create a dictionary from the tuple generator.
+    return dict(generate())
+
+
+def _get_typeshed_directories(version_info):
+    check_version_list = ['2and3', str(version_info.major)]
+    for base in ['stdlib', 'third_party']:
+        base = os.path.join(_TYPESHED_PATH, base)
+        base_list = os.listdir(base)
+        for base_list_entry in base_list:
+            match = re.match(r'(\d+)\.(\d+)$', base_list_entry)
+            if match is not None:
+                if int(match.group(1)) == version_info.major \
+                        and int(match.group(2)) <= version_info.minor:
+                    check_version_list.append(base_list_entry)
+
+        for check_version in check_version_list:
+            yield os.path.join(base, check_version)
 
 
 class TypeshedPlugin(BasePlugin):
-    def foo():
-        return
+    _version_cache = {}
+
+    def _cache_stub_file_map(self, version_info):
+        """
+        Returns a map of an importable name in Python to a stub file.
+        """
+        # TODO this caches the stub files indefinitely, maybe use a time cache
+        # for that?
+        version = version_info[:2]
+        try:
+            return self._version_cache[version]
+        except KeyError:
+            pass
+
+        self._version_cache[version] = file_set = {}
+        for dir_ in _get_typeshed_directories(version_info):
+            file_set.update(_create_stub_map(dir_))
+
+        return file_set
+
+    @evaluator_as_method_param_cache()
+    def _load_stub(self, evaluator, path):
+        return evaluator.parse(path=path, cache=True)
+
+    def import_module(self, callback):
+        def wrapper(evaluator, import_names, module_context, sys_path):
+            # This is a huge exception, we follow a nested import
+            # ``os.path``, because it's a very important one in Python
+            # that is being achieved by messing with ``sys.modules`` in
+            # ``os``.
+            mapped = self._cache_stub_file_map(evaluator.grammar.version_info)
+            context_set = callback(evaluator, import_names, module_context, sys_path)
+            if len(import_names) == 1:
+                path = mapped.get(import_names[0])
+                if path is not None:
+                    try:
+                        stub_module = self._load_stub(evaluator, path)
+                    except FileNotFoundError:
+                        # The file has since been removed after looking for it.
+                        # TODO maybe empty cache?
+                        pass
+                    else:
+                        return ContextSet.from_iterable(
+                            StubProxy(
+                                context.parent_context,
+                                context,
+                                ModuleContext(evaluator, stub_module, path, code_lines=[])
+                            ) for context in context_set
+                        )
+            return context_set
+        return wrapper
 
 
-class TypeshedProxy(object):
-    def __init__(self, parent_context, context, typeshed_context):
+class StubProxy(object):
+    def __init__(self, parent_context, context, stub_context):
         self.parent_context = parent_context
         self._context = context
-        self._typeshed_context = typeshed_context
+        self._stub_context = stub_context
 
     # We have to overwrite everything that has to do with trailers, name
     # lookups and filters to make it possible to route name lookups towards
@@ -20,10 +122,9 @@ class TypeshedProxy(object):
         context_results = self._context.py__getattribute__(
             *args, **kwargs
         )
-        typeshed_results = self._typeshed_context = py__getattribute__(
+        typeshed_results = self._stub_context.py__getattribute__(
             *args, **kwargs
         )
-        print(context_results, typeshed_results)
         return context_results
 
     def __getattr__(self, name):