changes I wanted to discuss.. but failed ;)

locking/managers.py

@@ -0,0 +1,28 @@
+import datetime
+
+from django.db import models
+from django.db.models import Q
+
+from locking import LOCK_TIMEOUT
+
+class LockManager(models.Manager):
+    def locked(self):
+        now = datetime.datetime.now()
+        qs = super(LockManager, self).get_query_set()
+        qs = qs.extra(select={'expires_at':'DATE_ADD(locked_at,INTERVAL 120 SECOND)'})
+        qs = qs.extra(where=['DATE_ADD(locked_at,INTERVAL %s SECOND) > %s'], params=[LOCK_TIMEOUT, now])
+        return qs
+
+    def unlocked(self):
+        now = datetime.datetime.now()
+        qs = super(LockManager, self).get_query_set()
+        qs = qs.extra(select={'expires_at':'DATE_ADD(locked_at,INTERVAL 120 SECOND)'})
+        qs = qs.extra(where=['DATE_ADD(locked_at,INTERVAL %s SECOND) < %s or locked_at IS NULL'], params=[LOCK_TIMEOUT, now])
+        return qs
+
+    def locked_for(self, user):
+        qs = super(LockManager, self).get_query_set()
+        qs = qs.extra(select={'expires_at':'DATE_ADD(locked_at,INTERVAL 120 SECOND)'})
+        qs = qs.extra(where=['DATE_ADD(locked_at,INTERVAL %s SECOND) > %s'], params=[LOCK_TIMEOUT, now])
+        qs = qs.filter(_locked_by = user)
+        return qs

locking/models.py

@@ -7,14 +7,17 @@
 from django.contrib.auth import models as auth
 
 from locking import LOCK_TIMEOUT, logger
+from locking.managers import LockManager
 
 class ObjectLockedError(IOError):
     pass
 
 class LockableModel(models.Model):
     class Meta:
         abstract = True
-
+
+    objects = LockManager()
+
     _locked_at = models.DateTimeField(db_column='locked_at', 
         null=True,
         editable=False)