move get_submodels into mapdata.utils.models

src/c3nav/mapdata/utils/models.py

@@ -0,0 +1,25 @@
+import typing
+
+from celery import chain
+from django.db import models
+
+
+_submodels_by_model = {}
+
+
+def get_submodels(model: typing.Type[models.Model]) -> typing.List[typing.Type[models.Model]]:
+    """
+    Get non-abstract submodels for a model including the model itself.
+    Result is cached.
+    """
+    try:
+        return _submodels_by_model[model]
+    except KeyError:
+        pass
+    all_models = model.__subclasses__()
+    result = []
+    if not model._meta.abstract:
+        result.append(model)
+    result.extend(chain(*(get_submodels(model) for model in all_models)))
+    _submodels_by_model[model] = result
+    return result