[Zope3-checkins] CVS: Zope3/src/zope/interface - declarations.py:1.17.10.5

[Jim Fulton]

Update of /cvs-repository/Zope3/src/zope/interface
In directory cvs.zope.org:/tmp/cvs-serv22218

Modified Files:
      Tag: adaptergeddon-branch
	declarations.py 
Log Message:
Added a test for the provides declaration cache.


=== Zope3/src/zope/interface/declarations.py 1.17.10.4 => 1.17.10.5 ===
--- Zope3/src/zope/interface/declarations.py:1.17.10.4	Sun Oct 12 18:34:03 2003
+++ Zope3/src/zope/interface/declarations.py	Mon Oct 13 11:08:59 2003
@@ -585,10 +585,6 @@
 #
 # Instance declarations
 
-# Registry of instance declarations
-# This is a memory optimization to allow objects to share specifications.
-InstanceDeclarations = weakref.WeakValueDictionary()
-
 class Provides(Declaration):
     """Implement __provides__, the instance-specific specification
 
@@ -633,7 +629,54 @@
 
 ProvidesClass = Provides
 
+# Registry of instance declarations
+# This is a memory optimization to allow objects to share specifications.
+InstanceDeclarations = weakref.WeakValueDictionary()
+
 def Provides(*interfaces):
+    """Cache instance declarations
+
+      Instance declarations are shared among instances that have the
+      same declaration.  The declarations are cached in an weak value
+      dictionary.
+
+      >>> import gc
+      >>> x = gc.collect()
+      >>> before = len(InstanceDeclarations)
+
+      >>> class C:
+      ...    pass
+
+      >>> from zope.interface import Interface
+      >>> class I(Interface):
+      ...    pass
+      
+      >>> c1 = C()
+      >>> c2 = C()
+
+      >>> len(InstanceDeclarations) == before
+      1
+
+      >>> directlyProvides(c1, I)
+      >>> len(InstanceDeclarations) == before + 1
+      1
+
+      >>> directlyProvides(c2, I)
+      >>> len(InstanceDeclarations) == before + 1
+      1
+
+      >>> del c1
+      >>> x = gc.collect()
+      >>> len(InstanceDeclarations) == before + 1
+      1
+
+      >>> del c2
+      >>> x = gc.collect()
+      >>> len(InstanceDeclarations) == before
+      1
+      
+      """
+    
     spec = InstanceDeclarations.get(interfaces)
     if spec is None:
         spec = ProvidesClass(*interfaces)