Change to standalone stoken objects (+ small optimisation).

Makes it possible to now generate Stokens as we need so we can add them to
non-revision objects, for example, membership changes.

We also slightly improved how we filter by revs.

django_etesync/views.py

@@ -35,7 +35,15 @@ import nacl.secret
 import nacl.hash
 
 from . import app_settings, permissions
-from .models import Collection, CollectionItem, CollectionItemRevision, CollectionMember, CollectionInvitation, UserInfo
+from .models import (
+        Collection,
+        CollectionItem,
+        CollectionItemRevision,
+        CollectionMember,
+        CollectionInvitation,
+        Stoken,
+        UserInfo,
+    )
 from .serializers import (
         b64encode,
         AuthenticationSignupSerializer,
@@ -94,18 +102,18 @@ class BaseViewSet(viewsets.ModelViewSet):
         user = self.request.user
         return queryset.filter(members__user=user)
 
-    def get_cstoken_rev(self, request):
+    def get_cstoken_obj(self, request):
         cstoken = request.GET.get('cstoken', None)
 
         if cstoken is not None:
-            return get_object_or_404(CollectionItemRevision.objects.all(), uid=cstoken)
+            return get_object_or_404(Stoken.objects.all(), uid=cstoken)
 
         return None
 
     def filter_by_cstoken(self, request, queryset):
         cstoken_id_field = self.cstoken_id_field + '__id'
 
-        cstoken_rev = self.get_cstoken_rev(request)
+        cstoken_rev = self.get_cstoken_obj(request)
         if cstoken_rev is not None:
             filter_by = {cstoken_id_field + '__gt': cstoken_rev.id}
             queryset = queryset.filter(**filter_by)
@@ -116,7 +124,7 @@ class BaseViewSet(viewsets.ModelViewSet):
         cstoken_id_field = self.cstoken_id_field + '__id'
 
         new_cstoken_id = queryset.aggregate(cstoken_id=Max(cstoken_id_field))['cstoken_id']
-        new_cstoken = new_cstoken_id and CollectionItemRevision.objects.get(id=new_cstoken_id).uid
+        new_cstoken = new_cstoken_id and Stoken.objects.get(id=new_cstoken_id).uid
 
         return queryset, new_cstoken
 
@@ -139,7 +147,7 @@ class CollectionViewSet(BaseViewSet):
     queryset = Collection.objects.all()
     serializer_class = CollectionSerializer
     lookup_field = 'uid'
-    cstoken_id_field = 'items__revisions'
+    cstoken_id_field = 'items__revisions__stoken'
 
     def get_queryset(self, queryset=None):
         if queryset is None:
@@ -199,7 +207,7 @@ class CollectionItemViewSet(BaseViewSet):
     queryset = CollectionItem.objects.all()
     serializer_class = CollectionItemSerializer
     lookup_field = 'uid'
-    cstoken_id_field = 'revisions'
+    cstoken_id_field = 'revisions__stoken'
 
     def get_queryset(self):
         collection_uid = self.kwargs['collection_uid']
@@ -290,8 +298,8 @@ class CollectionItemViewSet(BaseViewSet):
             queryset, cstoken_rev = self.filter_by_cstoken(request, queryset)
 
             uids, stokens = zip(*[(item['uid'], item.get('stoken')) for item in serializer.validated_data])
-            rev_ids = CollectionItemRevision.objects.filter(uid__in=stokens, current=True).values_list('id', flat=True)
-            queryset = queryset.filter(uid__in=uids).exclude(revisions__id__in=rev_ids)
+            revs = CollectionItemRevision.objects.filter(stoken__uid__in=stokens, current=True)
+            queryset = queryset.filter(uid__in=uids).exclude(revisions__in=revs)
 
             queryset, new_cstoken = self.get_queryset_cstoken(queryset)
             cstoken = cstoken_rev and cstoken_rev.uid