decodeAdvance method

Implementation

RitoBackgroundAdvance decodeAdvance(Uint8List bytes) {
  final reader = openRitoWireMessage(
    bytes,
    magic: 'RITOBGA1',
    label: 'background advance',
  );
  final state = _state(reader);
  final intentRequestId = reader.externalId('intent request id');
  final replacesArtifactId = reader.externalId('replaces artifact id');
  final movesVisibleContent = reader.boolean(
    'background moves visible content',
  );
  final artifactBytes = reader.blobView('background artifact');
  // Complete may carry exactly one artifact: the completion handoff
  // that delivers the book page count to a reader who never turned a
  // page. Indexing and candidatePending carry nothing by definition.
  if ((state == RitoBackgroundState.candidatePending ||
          state == RitoBackgroundState.indexing) &&
      artifactBytes.isNotEmpty) {
    reader.fail('$state background advance must not carry an artifact');
  }
  final artifact = artifactBytes.isEmpty
      ? null
      : artifactDecoder.decode(artifactBytes);
  reader.finish('background advance wire message');
  return RitoBackgroundAdvance(
    state: state,
    intentRequestId: intentRequestId,
    replacesArtifactId: replacesArtifactId,
    movesVisibleContent: movesVisibleContent && artifact != null,
    artifact: artifact,
  );
}