handle method

KeymapLayerResult handle(Msg msg)

Dispatch msg through this surface.

Implementation

KeymapLayerResult handle(Msg msg) {
  // Sequence timeouts are surface-scoped.
  if (msg is _SequenceTimeoutMsg) {
    if (msg.surfaceId != id) return const KeymapLayerPass();
    if (_pendingSessionId != msg.sessionId) {
      return const KeymapLayerDrop(); // stale
    }
    _clearPending();
    return KeymapLayerClaim(
      KeymapSequenceCancelledMsg(surfaceId: id, timedOut: true),
    );
  }

  if (bindings.isNotEmpty && msg is KeyMsg) {
    final seq = _handleKey(msg.key);
    if (seq != null) return seq;
  }

  final custom = onMessage;
  if (custom != null) {
    final result = custom(msg);
    if (result is! KeymapLayerPass) return result;
  }

  final nested = interceptor;
  if (nested != null) {
    final out = nested.onSend(msg);
    if (out == null) return const KeymapLayerDrop();
    // Nested interceptor always claims non-null results (Phase 0 contract).
    // Use bindings for fallthrough-aware catalogs; nested is opaque.
    return KeymapLayerClaim(out);
  }

  return const KeymapLayerPass();
}