add add_current_model and get_field_value to utils.py

src/c3nav/editor/utils.py

@@ -1,2 +1,31 @@
+from typing import Union
+
+from django.db import models
+
+
 def is_created_pk(pk):
     return isinstance(pk, str) and pk.startswith('c') and pk[1:].isnumeric()
+
+
+def get_current_obj(model, pk, only_field=None):
+    if is_created_pk(pk):
+        return model()
+    if only_field is not None:
+        return model.objects.only(only_field).get(pk=pk)
+    return model.objects.get(pk=pk)
+
+
+def get_field_value(obj, field: Union[str, models.Field]):
+    if isinstance(field, str):
+        name = field
+        model = type(obj)
+        field = model._meta.get_field('titles' if name.startswith('title_') else name)
+    else:
+        name = field.name
+    try:
+        current_value = getattr(obj, field.attname)
+    except AttributeError:
+        current_value = field.to_prep_value(getattr(obj, field.name))
+    if name.startswith('title_'):
+        current_value = current_value.get(name[6:], '')
+    return current_value