tod: Add support for device features, keeping ABI compatibility

libfprint/fpi-device.h

@@ -139,7 +139,6 @@ struct _FpDeviceClass
   const gchar     *full_name;
   FpDeviceType     type;
   const FpIdEntry *id_table;
-  FpDeviceFeature  features;
 
   /* Defaults for device properties */
   gint       nr_enroll_stages;
@@ -159,9 +158,12 @@ struct _FpDeviceClass
 
   void (*cancel)   (FpDevice *device);
 
+  /* Class elements added after tod-v1 */
+  FpDeviceFeature features;
+
   /*< private >*/
   /* padding for future expansion */
-  gpointer _padding_dummy[32];
+  gpointer _padding_dummy[31];
 };
 
 void fpi_device_class_auto_initialize_features (FpDeviceClass *device_class);

libfprint/tod/tod-shared-loader.c

@@ -127,6 +127,12 @@ fpi_tod_shared_drivers_register (void)
       fp_dbg ("Loading driver %s (%s)", cls->id, cls->full_name);
       g_array_append_val (shared_drivers, driver);
 
+      if (cls->features == FP_DEVICE_FEATURE_NONE)
+        {
+          g_debug ("Initializing features for driver %s", cls->id);
+          fpi_device_class_auto_initialize_features (cls);
+        }
+
       shared_modules = g_list_prepend (shared_modules,
                                        g_steal_pointer (&module));
     }