properly lock the DB

anki/db.py

@@ -14,9 +14,8 @@ except ImportError:
 from anki.hooks import runHook
 
 class DB(object):
-    def __init__(self, path, level="EXCLUSIVE", text=None):
-        self._db = sqlite.connect(
-            path, timeout=0, isolation_level=level)
+    def __init__(self, path, text=None):
+        self._db = sqlite.connect(path, timeout=0, isolation_level=None)
         if text:
             self._db.text_factory = text
         self._path = path

anki/deck.py

@@ -113,9 +113,14 @@ qconf=?, conf=?, data=?""",
             simplejson.dumps(self.conf), simplejson.dumps(self.data))
 
     def save(self):
-        "Flush, then commit DB."
+        "Flush, commit DB, and take out another write lock."
         self.flush()
         self.db.commit()
+        self.lock()
+
+    def lock(self):
+        self.db.execute("begin exclusive")
+        self.db.execute("update deck set mod=mod")
 
     def close(self, save=True):
         "Disconnect from DB."
@@ -135,6 +140,7 @@ qconf=?, conf=?, data=?""",
 
     def rollback(self):
         self.db.rollback()
+        self.lock()
 
     def modSchema(self):
         if not self.schemaDirty():

anki/storage.py

@@ -34,6 +34,7 @@ def Deck(path, queue=True):
     elif create:
         deck.addModel(BasicModel(deck))
         deck.save()
+    deck.lock()
     if not queue:
         return deck
     # rebuild queue