add rebuild arg for minimal startup

this bypasses rebuilding the queue and other startup initialization and thus
loads the deck considerably faster. This is useful when you want to perform
operations on the deck like syncing, but don't need the ability to review
cards

anki/deck.py

@@ -3556,7 +3556,7 @@ backupDir = os.path.expanduser("~/.anki/backups")
 
 class DeckStorage(object):
 
-    def Deck(path=None, backup=True, lock=True, pool=True):
+    def Deck(path=None, backup=True, lock=True, pool=True, rebuild=True):
         "Create a new deck or attach to an existing one."
         create = True
         if path is None:
@@ -3571,9 +3571,9 @@ class DeckStorage(object):
         try:
             (engine, session) = DeckStorage._attach(sqlpath, create, pool)
             s = session()
-            metadata.create_all(engine)
             if create:
                 ver = 999
+                metadata.create_all(engine)
                 deck = DeckStorage._init(s)
             else:
                 ver = s.scalar("select version from decks limit 1")
@@ -3596,6 +3596,8 @@ class DeckStorage(object):
                             s.execute("alter table " + st)
                         except:
                             pass
+                if ver < DECK_VERSION:
+                    metadata.create_all(engine)
                 deck = s.query(Deck).get(1)
                 if not deck:
                     raise DeckAccessError(_("Deck missing core table"),
@@ -3656,6 +3658,11 @@ class DeckStorage(object):
                                       type="inuse")
             else:
                 raise e
+        if not rebuild:
+            # minimal startup
+            deck._globalStats = globalStats(deck)
+            deck._dailyStats = dailyStats(deck)
+            return deck
         if needUnpack:
             deck.startProgress()
             DeckStorage._addIndices(deck)