--- a/PersonasBackend/personas/models.py	Thu Feb 14 19:08:23 2008 -0600
+++ b/PersonasBackend/personas/models.py	Thu Feb 14 23:13:16 2008 -0600
@@ -1,48 +1,5 @@
 from django.db import models
 
-def commitRevision( persona, user, changes ):
-    """
-    Commit changes to a persona as a user.
-
-    'persona' is the Persona object being changed.
-
-    'user' is the User object making the changes.
-
-    'changes' is a dictionary whose keys are the names of attributes
-    in 'persona' to change, with their new values.
-
-    Returns True if the commit was successful.  If the commit actually
-    would've resulted in no changes being made to the persona, False
-    is returned.
-    """
-
-    delta = {}
-
-    for attr in changes:
-        origValue = getattr( persona, attr )
-        newValue = changes[attr]
-        if origValue != newValue:
-            delta[attr] = origValue
-
-    if not delta:
-        return False
-
-    rev = Revision(
-        revision_of = persona,
-        date_updated = persona.date_updated,
-        updater = user,
-        revision = persona.revision
-        )
-
-    for attr in delta:
-        setattr( persona, attr, changes[attr] )
-        setattr( rev, attr, delta[attr] )
-
-    persona.save()
-    rev.save()
-
-    return True
-
 class User(models.Model):
     name = models.CharField(
         "Name of the user",
@@ -144,7 +101,7 @@
         User,
         verbose_name="User who made this revision",
         related_name="personas",
-        null=False,
+        null=True,
         )
 
     revision = models.PositiveIntegerField(
@@ -167,8 +124,88 @@
     def __str__(self):
         return self.name
 
+    VERSIONED_PROPERTIES = [
+        "name",
+        "category",
+        "description",
+        "header_img",
+        "footer_img",
+        "url",
+        "update_interval",
+        "color_scheme",
+        "status",
+        ]
+
+    def __makeNewRevision(self):
+        """
+        Detect if any of our versioned properties have changed, and if
+        so, make a new revision.
+        """
+
+        original = Persona.objects.get(id=self.id)
+
+        assert original.revision == self.revision
+        assert original.date_updated == self.date_updated
+
+        delta = {}
+        for attr in self.VERSIONED_PROPERTIES:
+            origValue = getattr(original, attr)
+            newValue = getattr(self, attr)
+            if origValue != newValue:
+                delta[attr] = origValue
+        if delta:
+            rev = Revision(
+                revision_of = original,
+                date_updated = original.date_updated,
+                updater = original.updater,
+                revision = original.revision
+                )
+
+            for attr in delta:
+                setattr(rev, attr, delta[attr])
+            rev.save()
+
+            self.revision += 1
+
+    def save(self):
+        """
+        Saves the object.  If a versioned property is changed, a new
+        revision is generated automatically.
+
+        Example:
+
+          >>> c = Category(name='General')
+          >>> c.save()
+
+          >>> p = Persona(name='Test Persona',
+          ...             description='Thos is a test.',
+          ...             category=c,
+          ...             status='published')
+          >>> p.save()
+          >>> p.revision
+          0
+          >>> p.revisions.all()
+          []
+
+          >>> p.description = 'This is a test.'
+          >>> p.save()
+          >>> p.revision
+          1
+          >>> p.revisions.all()
+          [<Revision: Test Persona - r0>]
+          >>> p.revisions.get(revision=0).description
+          'Thos is a test.'
+        """
+
+        if self.id == None:
+            self.revision = 0
+        else:
+            self.__makeNewRevision()
+
+        super(Persona, self).save()
+
 class Revision(models.Model):
-    # Non-null fields
+    # Auto-generated fields
 
     revision_of = models.ForeignKey(
         Persona,
@@ -184,14 +221,14 @@
     updater = models.ForeignKey(
         User,
         related_name="revisions",
-        null=False,
+        null=True,
         )
 
     revision = models.PositiveIntegerField(
         null=False,
         )
 
-    # Null fields
+    # Versioned fields
 
     name = models.CharField(
         maxlength=Persona.MAX_NAME_LENGTH,