# HG changeset patch
# User Thierry Florac <thierry.florac@onf.fr>
# Date 1523366012 -7200
# Node ID 47b6b7d92f4aa4a31d215a3ded3a1cfd2f4c7ec5
# Parent  6376d1ff2918ab7da514715daa5ae365cf352e75
Added "empty" (rendering an empty string) viewlet and content provider as base classes

diff -r 6376d1ff2918 -r 47b6b7d92f4a src/pyams_viewlet/viewlet.py
--- a/src/pyams_viewlet/viewlet.py	Tue Apr 03 15:22:12 2018 +0200
+++ b/src/pyams_viewlet/viewlet.py	Tue Apr 10 15:13:32 2018 +0200
@@ -28,8 +28,8 @@
 
 
 @implementer(IContentProvider)
-class BaseContentProvider(object):
-    """Base template based content provider"""
+class EmptyContentProvider(object):
+    """Empty content provider base class"""
 
     permission = None
 
@@ -37,15 +37,22 @@
         self.context = context
         self.request = request
 
-    def update(self):
-        pass
-
     def __call__(self):
         if self.permission and not self.request.has_permission(self.permission, context=self.context):
             return ''
         self.update()
         return self.render()
 
+    def update(self):
+        pass
+
+    def render(self):
+        return ''
+
+
+class BaseContentProvider(EmptyContentProvider):
+    """Base template based content provider"""
+
     render = get_view_template()
 
 
@@ -113,8 +120,8 @@
 
 
 @implementer(IViewlet)
-class Viewlet(object):
-    """Viewlet adapter class used in meta directive as a mixin class."""
+class EmptyViewlet(object):
+    """Empty viewlet base class"""
 
     permission = None
 
@@ -127,6 +134,13 @@
     def update(self):
         pass
 
+    def render(self):
+        return ''
+
+
+class Viewlet(EmptyViewlet):
+    """Viewlet adapter class used in meta directive as a mixin class."""
+
     render = get_view_template()