pybricks.common.System: Implement reset_storage.

CHANGELOG.md

@@ -7,11 +7,13 @@
 ### Added
 
 - Added optional `calibrated=True` parameter to `acceleration()` and `up()` and
-  `angular_velocity()` methods of the IMU ([support#943]).
+  `angular_velocity()` and `rotation` methods of the IMU ([support#943]).
 - Implemented `hub.imu.orientation()` to give the rotation matrix of the hub or
   robot with respect to the inertial frame.
 - Added calibration parameters that can be set for angular velocity offset and
   scale and acceleration offset and scale.
+- Added `hub.system.reset_storage` to restore storage and settings to default
+  state.
 
 ### Changed
 

lib/pbio/sys/storage.c

@@ -176,7 +176,8 @@ void pbsys_storage_request_write(void) {
 
 /**
  * Erases user data, erases user program meta data and restores user settings
- * to default.
+ * to default. Does not actually erase program data, but it becomes
+ * inaccessible, thus effectively erased.
  *
  * This resets the data in RAM, which will be saved during power off just as
  * with any other storage operations.
@@ -188,6 +189,8 @@ void pbsys_storage_request_write(void) {
 void pbsys_storage_reset_storage(void) {
     // Reset storage except for program data. It is sufficient to set its
     // size to 0, which is what happens here since it is in the map.
+    // The program data itself is not overwritten with zeros because the user
+    // may be calling this while a program using this data is running.
     memset(map, 0, sizeof(pbsys_storage_data_map_t));
 
     // Apply default settings.

pybricks/common/pb_type_system.c

@@ -142,6 +142,12 @@ static mp_obj_t pb_type_System_storage(size_t n_args, const mp_obj_t *pos_args,
 }
 static MP_DEFINE_CONST_FUN_OBJ_KW(pb_type_System_storage_obj, 0, pb_type_System_storage);
 
+static mp_obj_t pb_type_System_reset_storage(void) {
+    pbsys_storage_reset_storage();
+    return mp_const_none;
+}
+static MP_DEFINE_CONST_FUN_OBJ_0(pb_type_System_reset_storage_obj, pb_type_System_reset_storage);
+
 #endif // PBIO_CONFIG_ENABLE_SYS
 
 // dir(pybricks.common.System)
@@ -153,6 +159,7 @@ static const mp_rom_map_elem_t common_System_locals_dict_table[] = {
     #endif // PBDRV_CONFIG_RESET
     #if PBIO_CONFIG_ENABLE_SYS
     { MP_ROM_QSTR(MP_QSTR_set_stop_button), MP_ROM_PTR(&pb_type_System_set_stop_button_obj) },
+    { MP_ROM_QSTR(MP_QSTR_reset_storage), MP_ROM_PTR(&pb_type_System_reset_storage_obj) },
     { MP_ROM_QSTR(MP_QSTR_shutdown), MP_ROM_PTR(&pb_type_System_shutdown_obj) },
     { MP_ROM_QSTR(MP_QSTR_storage), MP_ROM_PTR(&pb_type_System_storage_obj) },
     #endif