Add a Set and SetOfIntegers object fields

Object fields that represent sets of things. Will be useful for NUMA
topology object which will be added in subsequent patches.

Change-Id: I66d61c760a70ad661dff4c40c6933df06192ee8f
Blueprint: virt-driver-numa-placement

nova/objects/fields.py

@@ -434,6 +434,30 @@ class Dict(CompoundFieldType):
                       for key, val in sorted(value.items())]))
 
 
+class Set(CompoundFieldType):
+    def coerce(self, obj, attr, value):
+        if not isinstance(value, set):
+            raise ValueError(_('A set is required here'))
+
+        coerced = set()
+        for element in value:
+            coerced.add(self._element_type.coerce(
+                obj, '%s["%s"]' % (attr, element), element))
+        return coerced
+
+    def to_primitive(self, obj, attr, value):
+        return tuple(
+            self._element_type.to_primitive(obj, attr, x) for x in value)
+
+    def from_primitive(self, obj, attr, value):
+        return set([self._element_type.from_primitive(obj, attr, x)
+                    for x in value])
+
+    def stringify(self, value):
+        return 'set([%s])' % (
+            ','.join([self._element_type.stringify(x) for x in value]))
+
+
 class Object(FieldType):
     def __init__(self, obj_name, **kwargs):
         self._obj_name = obj_name
@@ -575,6 +599,10 @@ class ListOfStringsField(AutoTypedField):
     AUTO_TYPE = List(String())
 
 
+class SetOfIntegersField(AutoTypedField):
+    AUTO_TYPE = Set(Integer())
+
+
 class ListOfDictOfNullableStringsField(AutoTypedField):
     AUTO_TYPE = List(Dict(String(), nullable=True))
 

nova/tests/objects/test_fields.py

@@ -271,6 +271,34 @@ class TestListOfStrings(TestField):
         self.assertEqual("['abc']", self.field.stringify(['abc']))
 
 
+class TestSet(TestField):
+    def setUp(self):
+        super(TestSet, self).setUp()
+        self.field = fields.Field(fields.Set(FakeFieldType()))
+        self.coerce_good_values = [(set(['foo', 'bar']),
+                                    set(['*foo*', '*bar*']))]
+        self.coerce_bad_values = [['foo'], {'foo': 'bar'}]
+        self.to_primitive_values = [(set(['foo']), tuple(['!foo!']))]
+        self.from_primitive_values = [(tuple(['!foo!']), set(['foo']))]
+
+    def test_stringify(self):
+        self.assertEqual('set([123])', self.field.stringify(set([123])))
+
+
+class TestSetOfIntegers(TestField):
+    def setUp(self):
+        super(TestSetOfIntegers, self).setUp()
+        self.field = fields.SetOfIntegersField()
+        self.coerce_good_values = [(set(['1', 2]),
+                                    set([1, 2]))]
+        self.coerce_bad_values = [set(['foo'])]
+        self.to_primitive_values = [(set([1]), tuple([1]))]
+        self.from_primitive_values = [(tuple([1]), set([1]))]
+
+    def test_stringify(self):
+        self.assertEqual('set([1,2])', self.field.stringify(set([1, 2])))
+
+
 class TestObject(TestField):
     def setUp(self):
         super(TestObject, self).setUp()