register updated geometries for tile cache invalidation

src/c3nav/mapdata/render/cache.py

@@ -0,0 +1,53 @@
+from django.db.models.signals import m2m_changed, post_delete
+
+from c3nav.mapdata.utils.models import get_submodels
+
+
+class GeometryChangeTracker:
+    def __init__(self):
+        self._geometries_by_level = {}
+        self._deleted_levels = set()
+
+    def register(self, level_id, geometry):
+        self._geometries_by_level.setdefault(level_id, []).append(geometry)
+
+    def level_deleted(self, level_id):
+        self._deleted_levels.add(level_id)
+
+    def reset(self):
+        self._geometries_by_level = {}
+        self._deleted_levels = set()
+
+
+changed_geometries = GeometryChangeTracker()
+
+
+def geometry_deleted(sender, instance, **kwargs):
+    instance.register_delete()
+
+
+def locationgroup_changed(sender, instance, action, reverse, model, pk_set, using, **kwargs):
+    if action not in ('post_add', 'post_remove', 'post_clear'):
+        return
+
+    if not reverse:
+        instance.register_change(force=True)
+    else:
+        if action not in 'post_clear':
+            raise NotImplementedError
+        query = model.objects.filter(pk__in=pk_set)
+        from c3nav.mapdata.models.geometry.space import SpaceGeometryMixin
+        if issubclass(model, SpaceGeometryMixin):
+            query = query.select_related('space')
+        for obj in query:
+            obj.register_change(force=True)
+
+
+def register_signals():
+    from c3nav.mapdata.models.geometry.base import GeometryMixin
+    for model in get_submodels(GeometryMixin):
+        post_delete.connect(geometry_deleted, sender=model)
+
+    from c3nav.mapdata.models.locations import SpecificLocation
+    for model in get_submodels(SpecificLocation):
+        m2m_changed.connect(locationgroup_changed, sender=model.groups.through)