Allow default to be specified as a list of flag names

bitfield/models.py

@@ -6,7 +6,7 @@
     from django.db.models.fields.subclassing import SubfieldBase
 except ImportError:
     # django 1.2
-    from django.db.models.fields.subclassing import LegacyConnection as SubfieldBase
+    from django.db.models.fields.subclassing import LegacyConnection as SubfieldBase  # NOQA
 
 from bitfield.forms import BitFormField
 from bitfield.query import BitQueryLookupWrapper
@@ -96,7 +96,7 @@ def contribute_to_class(self, cls, name):
 class BitField(BigIntegerField):
     __metaclass__ = BitFieldMeta
 
-    def __init__(self, flags, *args, **kwargs):
+    def __init__(self, flags, default=None, *args, **kwargs):
         if isinstance(flags, dict):
             # Get only integer keys in correct range
             valid_keys = (k for k in flags.keys() if isinstance(k, int) and (0 <= k < MAX_FLAG_COUNT))
@@ -108,7 +108,13 @@ def __init__(self, flags, *args, **kwargs):
         if len(flags) > MAX_FLAG_COUNT:
             raise ValueError('Too many flags')
 
-        BigIntegerField.__init__(self, *args, **kwargs)
+        if isinstance(default, (list, tuple, set, frozenset)):
+            new_value = 0
+            for flag in default:
+                new_value |= Bit(flags.index(flag))
+            default = new_value
+
+        BigIntegerField.__init__(self, default=default, *args, **kwargs)
         self.flags = flags
 
     def south_field_triple(self):

bitfield/tests/models.py

@@ -2,6 +2,7 @@
 
 from bitfield import BitField, CompositeBitField
 
+
 class BitFieldTestModel(models.Model):
     flags = BitField(flags=(
         'FLAG_0',
@@ -10,6 +11,7 @@ class BitFieldTestModel(models.Model):
         'FLAG_3',
     ), default=3, db_column='another_name')
 
+
 class CompositeBitFieldTestModel(models.Model):
     flags_1 = BitField(flags=(
         'FLAG_0',
@@ -27,4 +29,3 @@ class CompositeBitFieldTestModel(models.Model):
         'flags_1',
         'flags_2',
     ))
-

bitfield/tests/tests.py

@@ -1,6 +1,6 @@
 import pickle
 
-from django.db import connection
+from django.db import connection, models
 from django.db.models import F
 from django.test import TestCase
 
@@ -248,6 +248,17 @@ def test_dictionary_init(self):
         self.assertRaises(ValueError, BitField, flags={'wrongkey': 'wrongkey'})
         self.assertRaises(ValueError, BitField, flags={'1': 'non_int_key'})
 
+    def test_defaults_as_key_names(self):
+        class TestModel(models.Model):
+            flags = BitField(flags=(
+                'FLAG_0',
+                'FLAG_1',
+                'FLAG_2',
+                'FLAG_3',
+            ), default=('FLAG_1', 'FLAG_2'))
+        field = TestModel._meta.get_field('flags')
+        self.assertEquals(field.default, TestModel.flags.FLAG_1 | TestModel.flags.FLAG_2)
+
 
 class BitFieldSerializationTest(TestCase):
     def test_can_unserialize_bithandler(self):