Method restoreDataProcessors

pj_app/src/MainWindow.cpp:3164–3262

}

void MainWindow::restoreDataProcessors(const QDomElement& root) {
  // Reconcile the live filter set to this snapshot: drop ALL current filters first,
  // then recreate the snapshot's set. This makes restore idempotent for undo/redo (no
  // duplicate or output-name-colliding filters) and correct for a layout load onto an
  // existing session. A snapshot with NO <data_processors> still falls through to clear
  // every filter; the rebuild at the end MUST run on both branches so the now-retired
  // outputs leave the catalog.
  auto& service = session_->sessionManager().dataProcessorService();
  service.clearAllFilters();

  const QDomElement element = root.firstChildElement(QStringLiteral("data_processors"));
  const auto datasets = session_->catalogModel().datasets();
  // A null <data_processors> yields a null firstChildElement, so this loop runs zero
  // times — the clear above is then the whole effect.
  for (QDomElement processor = element.firstChildElement(QStringLiteral("processor")); !processor.isNull();
       processor = processor.nextSiblingElement(QStringLiteral("processor"))) {
    const QString input_topic = processor.attribute(QStringLiteral("input_topic"));
    const QString input_field = processor.attribute(QStringLiteral("input_field"));
    // Resolve the input against whichever loaded dataset holds it (first match in
    // load order), so a multi-file layout restores each filter against its source.
    std::optional<CurveDescriptor> input_desc;
    for (const auto& [dataset_id, dataset_name] : datasets) {
      (void)dataset_name;
      if (auto descriptor = session_->catalogModel().descriptorForPath(dataset_id, input_topic, input_field)) {
        input_desc = std::move(descriptor);
        break;
      }
    }
    if (!input_desc.has_value()) {
      // The filter's source signal isn't in any loaded dataset -> the filter is
      // dropped. Tell the user which one, mirroring the unknown/apply-failed cases
      // below (otherwise a derived series silently vanishes on layout load).
      emitDiagnostic(
          DiagnosticLevel::kWarning, "Layout", "processor-input-missing",
          tr("Layout filter on '%1/%2' has no matching data; skipping.").arg(input_topic, input_field));
      continue;
    }
    const std::string id = processor.attribute(QStringLiteral("processor_id")).toStdString();
    // Params are the <processor>'s OWN direct CDATA — directCdataText ignores the
    // <source_fallback> child (QDomElement::text() would recurse and merge them).
    const QString params = layout_xml::directCdataText(processor);
    const QString source_fallback = processor.firstChildElement(QStringLiteral("source_fallback")).text();
    // Resolve order: live catalogue → embedded source → transitional C++ builtin.
    std::unique_ptr<proc::DataProcessor> built = service.makeRestoredProcessor(
        id, params.isEmpty() ? std::string("{}") : params.toStdString(), source_fallback.toStdString());
    if (!built) {
      emitDiagnostic(
          DiagnosticLevel::kWarning, "Layout", "processor-unknown",
          tr("Layout filter '%1' is unknown to this PlotJuggler; skipping.").arg(QString::fromStdString(id)));
      continue;
    }
    const auto applied = service.applyFilter(
        input_desc->topic_id, input_desc->dataset_id, std::move(built),
        processor.attribute(QStringLiteral("output_name")).toStdString(), input_desc->column_index);
    if (!applied.has_value()) {
      emitDiagnostic(
          DiagnosticLevel::kWarning, "Layout", "processor-apply-failed",
          tr("Could not restore filter: %1").arg(QString::fromStdString(applied.error())));