Method appendDataSourceElement

pj_app/src/MainWindow.cpp:3455–3554

}

QDomElement MainWindow::appendDataSourceElement(QDomDocument& doc, const QDir& layout_dir) const {
  const auto& sources = session_->sessionManager().loadedSources();
  // Do not save a data-source reference after the catalog was cleared.
  if (sources.empty() || session_->catalogModel().isEmpty()) {
    return QDomElement();
  }

  // Persist only sources that still back a live dataset. A dataset whose curves
  // were all removed (Remove Dataset, or trashing every topic) drops out of
  // datasets(), so its file is neither serialized here nor resurrected on the
  // next reload — while loaded_sources_ itself stays intact for the quick-reload
  // button (which keys off lastLoadedSource, not this list). FileLoader owns the
  // DatasetId->path link the engine's basename-only DatasetInfo can't provide.
  QSet<QString> live_paths;
  QHash<QString, DatasetId> dataset_for_path;  // reverse of sourcePathForDataset, for offset lookup
  for (const auto& [id, name] : session_->catalogModel().datasets()) {
    (void)name;
    if (const QString src_path = file_loader_->sourcePathForDataset(id); !src_path.isEmpty()) {
      live_paths.insert(src_path);
      dataset_for_path.insert(src_path, id);
    }
  }

  // Source Timeline arrangement: the bar's top-to-bottom slot, persisted per
  // file so the vertical order round-trips (re-bound by path on reload). Build
  // dataset -> slot once; absent => fall back to load order on restore.
  QHash<DatasetId, int> timeline_order;
  if (source_timeline_controller_ != nullptr) {
    const std::vector<DatasetId> order = source_timeline_controller_->currentTrackOrder();
    for (int i = 0; i < static_cast<int>(order.size()); ++i) {
      timeline_order.insert(order[static_cast<std::size_t>(i)], i);
    }
  }

  QDomElement wrapper = doc.createElement(QStringLiteral("previouslyLoaded_Datafiles"));

  // One <fileInfo> per loaded file, in load order, so a multi-file session
  // round-trips. Old PJ4 readers that only read the first child degrade to the
  // first file; new readers restore them all.
  for (const auto& src : sources) {
    if (!live_paths.contains(src.path)) {
      continue;  // dataset removed since load; don't resurrect it on reload
    }
    QDomElement file_info = doc.createElement(QStringLiteral("fileInfo"));

    const QFileInfo info(src.path);
    const QString abs = info.absoluteFilePath();
    const QString rel = layout_dir.relativeFilePath(abs);
    // Prefer the relative form when the data lives at or beneath the layout
    // dir; fall back to absolute when it escapes. This diverges from PJ3,
    // which always stores relative — PJ4 avoids brittle ../.. paths so that
    // moving a layout file doesn't silently break the data reference.
    // A relative path is a "subpath" only when Qt's relativeFilePath did
    // NOT emit a "../" prefix or the literal ".." path. The earlier check
    // (`!rel.startsWith("..")`) would misclassify legitimate filenames
    // like "..foo" or "..bar/data.csv" as escaping the dir.
    const bool is_subpath = rel != QStringLiteral("..") && !rel.startsWith(QStringLiteral("../"));
    file_info.setAttribute(QStringLiteral("filename"), is_subpath ? rel : abs);