Group value indexes functions into a class

src/Products/ZCatalog/plan.py

@@ -28,29 +28,27 @@ REPORTS = {}
 PRIORITYMAP_LOCK = allocate_lock()
 PRIORITYMAP = {}
 
-VALUE_INDEXES_LOCK = allocate_lock()
-VALUE_INDEXES = frozenset()
 
+class ValueIndexes(object):
 
-def get_value_indexes():
-    return VALUE_INDEXES
+    lock = allocate_lock()
+    value = frozenset()
 
+    @classmethod
+    def get(cls):
+        return cls.value
 
-def set_value_indexes(value):
-    with VALUE_INDEXES_LOCK:
-        global VALUE_INDEXES
-        VALUE_INDEXES = value
+    @classmethod
+    def set(cls, value):
+        with cls.lock:
+            cls.value = value
 
+    @classmethod
+    def clear(cls):
+        cls.set(frozenset())
 
-def clear_value_indexes():
-    set_value_indexes(frozenset())
-
-from zope.testing.cleanup import addCleanUp
-addCleanUp(clear_value_indexes)
-del addCleanUp
-
-
-def determine_value_indexes(indexes):
+    @classmethod
+    def determine(cls, indexes):
         # This function determines all indexes whose values should be respected
         # in the report key. The number of unique values for the index needs to be
         # lower than the MAX_DISTINCT_VALUES watermark.
@@ -59,7 +57,7 @@ def determine_value_indexes(indexes):
         # of unique values, where the number of items for each value differs a
         # lot. If the number of items per value is similar, the duration of a
         # query is likely similar as well.
-    value_indexes = get_value_indexes()
+        value_indexes = cls.get()
         if value_indexes:
             # Calculating all the value indexes is quite slow, so we do this once
             # for the first query. Since this is an optimization only, slightly
@@ -76,16 +74,20 @@ def determine_value_indexes(indexes):
                     # greater than zero
                     value_indexes.add(name)
 
-    set_value_indexes(frozenset(value_indexes))
+        cls.set(frozenset(value_indexes))
         return value_indexes
 
+from zope.testing.cleanup import addCleanUp
+addCleanUp(ValueIndexes.clear)
+del addCleanUp
+
 
 def make_key(catalog, query):
     if not query:
         return None
 
     indexes = catalog.indexes
-    valueindexes = determine_value_indexes(indexes)
+    valueindexes = ValueIndexes.determine(indexes)
     key = keys = query.keys()
 
     values = [name for name in keys if name in valueindexes]

src/Products/ZCatalog/tests/test_plan.py

@@ -41,8 +41,8 @@ class TestCatalogPlan(unittest.TestCase):
             self.zcat.catalog_object(obj, str(i))
 
     def tearDown(self):
-        from Products.ZCatalog.plan import clear_value_indexes
-        clear_value_indexes()
+        from Products.ZCatalog.plan import ValueIndexes
+        ValueIndexes.clear()
 
     def test_ReportLength(self):
         """ tests the report aggregation """