plugable: simplify API plugin initialization code

Use a flat dictionary to track plugins in API rather than nested
dictionaries.

https://fedorahosted.org/freeipa/ticket/4739

Reviewed-By: David Kupka <dkupka@redhat.com>

1 files changed, 29 insertions, 32 deletions

diff --git a/ipalib/plugable.py b/ipalib/plugable.py
index e8b5eb9c6..ed63ec646 100644
--- a/ipalib/plugable.py
+++ b/ipalib/plugable.py
@@ -574,41 +574,37 @@ class API(ReadOnly):
             raise TypeError('plugin must be a class; got %r' % klass)
 
         # Find the base class or raise SubclassError:
-        found = False
         for base in self.bases:
-            if not issubclass(klass, base):
-                continue
-
-            sub_d = self.__plugins.setdefault(base, {})
-            found = True
-
-            # Check override:
-            if klass.__name__ in sub_d:
-                if not override:
-                    # Must use override=True to override:
-                    raise errors.PluginOverrideError(
-                        base=base.__name__,
-                        name=klass.__name__,
-                        plugin=klass,
-                    )
-            else:
-                if override:
-                    # There was nothing already registered to override:
-                    raise errors.PluginMissingOverrideError(
-                        base=base.__name__,
-                        name=klass.__name__,
-                        plugin=klass,
-                    )
-
-            # The plugin is okay, add to sub_d:
-            sub_d[klass.__name__] = klass
-
-        if not found:
+            if issubclass(klass, self.bases):
+                break
+        else:
             raise errors.PluginSubclassError(
                 plugin=klass,
                 bases=self.bases,
             )
 
+        # Check override:
+        prev = self.__plugins.get(klass.__name__)
+        if prev:
+            if not override:
+                # Must use override=True to override:
+                raise errors.PluginOverrideError(
+                    base=base.__name__,
+                    name=klass.__name__,
+                    plugin=klass,
+                )
+        else:
+            if override:
+                # There was nothing already registered to override:
+                raise errors.PluginMissingOverrideError(
+                    base=base.__name__,
+                    name=klass.__name__,
+                    plugin=klass,
+                )
+
+        # The plugin is okay, add to sub_d:
+        self.__plugins[klass.__name__] = klass
+
     def finalize(self):
         """
         Finalize the registration, instantiate the plugins.
@@ -625,10 +621,11 @@ class API(ReadOnly):
 
         for base in self.bases:
             name = base.__name__
-            sub_d = self.__plugins.get(base, {})
-
             members = []
-            for klass in sub_d.values():
+
+            for klass in self.__plugins.values():
+                if not issubclass(klass, base):
+                    continue
                 try:
                     instance = plugins[klass]
                 except KeyError: