dvClearKioskSession function

Future<void> dvClearKioskSession(Set<DVKioskClearable> what, { DVKioskScope scope = DVKioskScope.device, String? namespace, })

Clears what from the framework's own state.

scope decides how far a shared-store clear reaches, and the difference is the point of the specification's table. In device scope the whole store is the kiosk's. In display scope only namespace is -- kiosk.<name> -- because a customer display timing out must not empty the store the cashier's window is working out of. A display-scope clear with no namespace touches the store not at all: the only alternative to clearing one window's keys is clearing everybody's.

Anything that throws is left to throw. The runtime turns a failed clear into DVKioskState.failed, and a session half-cleared and presented as fresh is the one outcome worse than a kiosk that visibly stopped.

Implementation

Future<void> dvClearKioskSession(
  Set<DVKioskClearable> what, {
  DVKioskScope scope = DVKioskScope.device,
  String? namespace,
}) async {
  if (what.contains(DVKioskClearable.clientCache)) {
    await const DVCache().delete(DVCache.all);
  }
  if (what.contains(DVKioskClearable.auth)) {
    // Display scope never reaches here: a policy listing auth in display
    // scope is refused by the parser, because the session is the staff
    // window's.
    await const DVAuth().signOut();
  }
  if (what.contains(DVKioskClearable.sharedStore)) {
    if (scope == DVKioskScope.device) {
      await _clearStore(DVWindowManager.shared, prefix: null);
    } else if (namespace != null) {
      await _clearStore(DVWindowManager.shared, prefix: '$namespace.');
    }
  }
  // signals and forms: see the library comment. The application's own
  // callback is what reaches them, and DV.global registrations are
  // deliberately not touched -- an application registers its API client
  // there at boot, and a kiosk that dropped it on every idle timeout would
  // stop working after ninety seconds.
}