Combine separate VendorImporters into a single one in pkg_resources.extern

--HG--
branch : feature/issue-229

pkg_resources/__init__.py

@@ -87,7 +87,6 @@ try:
 except ImportError:
     pass
 
-
 from pkg_resources.extern import packaging
 __import__('pkg_resources.extern.packaging.version')
 __import__('pkg_resources.extern.packaging.specifiers')

pkg_resources/extern/__init__.py

 import sys
 
+
 class VendorImporter:
     """
     A PEP 302 meta path importer for finding optionally-vendored

setuptools/extern/__init__.py

-import sys
+from pkg_resources.extern import VendorImporter
 
-class VendorImporter:
-    """
-    A PEP 302 meta path importer for finding optionally-vendored
-    or otherwise naturally-installed packages from root_name.
-    """
-    def __init__(self, root_name, vendored_names=(), vendor_pkg=None):
-        self.root_name = root_name
-        self.vendored_names = set(vendored_names)
-        self.vendor_pkg = vendor_pkg or root_name.replace('extern', '_vendor')
-
-    @property
-    def search_path(self):
-        yield self.vendor_pkg + '.'
-        yield ''
-
-    def find_module(self, fullname, path=None):
-        root, base, target = fullname.partition(self.root_name + '.')
-        if root:
-            return
-        if not any(map(target.startswith, self.vendored_names)):
-            return
-        return self
-
-    def load_module(self, fullname):
-        root, base, target = fullname.partition(self.root_name + '.')
-        for prefix in self.search_path:
-            try:
-                __import__(prefix + target)
-                mod = sys.modules[fullname] = sys.modules.pop(prefix + target)
-                return mod
-            except ImportError:
-                pass
-        else:
-            raise ImportError(
-                "The '{target}' package is required; "
-                "normally this is bundled with this package so if you get "
-                "this warning, consult the packager of your "
-                "distribution.".format(**locals())
-            )
-
-    def install(self):
-        if self not in sys.meta_path:
-            sys.meta_path.append(self)
 
 names = 'six',
 VendorImporter(__name__, names).install()