handlePortExpandThrough method

Future<SchematicLayoutResult?> handlePortExpandThrough(
  1. String nodeId,
  2. String portId
)

Handle incremental port expansion with pass-through traversal.

Like handlePortExpand but continues through trivial gates (buffers, inverters, slicers, concatenators) until non-trivial children or external ports are reached. Triggered by Shift+clicking a port marker in the schematic canvas.

Implementation

Future<SchematicLayoutResult?> handlePortExpandThrough(
  String nodeId,
  String portId,
) async {
  if (isToggling) {
    return null;
  }
  final engine = _layoutEngine;
  if (engine == null || schematicAdapter == null) {
    return null;
  }

  if (needsConnectivity(nodeId)) {
    setState(() {
      isToggling = true;
      togglingLabel = 'Expanding...';
      pendingToggleNodeId = nodeId;
    });
    final completer = Completer<void>();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      completer.complete();
    });
    await completer.future;
    SchedulerBinding.instance.ensureVisualUpdate();
    await ensureConnectivity(nodeId);
  } else {
    isToggling = true;
    pendingToggleNodeId = nodeId;
    await ensureConnectivity(nodeId); // fast no-op
  }

  final preExpandSnapshot = schematicAdapter!.schematic.expansionSnapshot();
  try {
    final expanded = schematicAdapter!.expandPortThroughRecursive(
      nodeId,
      portId,
    );
    if (!expanded) {
      if (mounted) {
        setState(() {
          isToggling = false;
          pendingToggleNodeId = null;
        });
      }
      return null;
    }

    final elkGraph = schematicAdapter!.schematic.toJsGraph();
    final newLayout = await engine.computeLayoutFromElkGraph(
      elkGraph,
      sessionId: _sessionId,
    );

    if (newLayout.hasError || !mounted) {
      schematicAdapter!.schematic.restoreExpansionSnapshot(preExpandSnapshot);
      if (mounted) {
        setState(() {
          isToggling = false;
          pendingToggleNodeId = null;
        });
      }
      return null;
    }

    setState(() {
      layout = newLayout;
      isToggling = false;
      pendingToggleNodeId = null;
      focusPortId = portId;
      recentlyToggledNodeId = null;
    });

    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) {
        setState(() {
          focusPortId = null;
        });
      }
    });

    return newLayout;
  } on Exception {
    schematicAdapter!.schematic.restoreExpansionSnapshot(preExpandSnapshot);
    if (mounted) {
      setState(() {
        isToggling = false;
        pendingToggleNodeId = null;
      });
    }
    return null;
  }
}