cabana: fix seeking issue (#28346)

* fix seekto

* rename loadThumbnail to parseQLog

tools/cabana/videowidget.cc

@@ -157,26 +157,31 @@ Slider::Slider(QWidget *parent) : thumbnail_label(parent), QSlider(Qt::Horizonta
     update();
   });
   timer->start(2000);
-  thumnail_future = QtConcurrent::run(this, &Slider::loadThumbnails);
+  QObject::connect(can, &AbstractStream::eventsMerged, [this]() {
+    if (!qlog_future) {
+      qlog_future = std::make_unique<QFuture<void>>(QtConcurrent::run(this, &Slider::parseQLog));
+    }
+  });
 }
 
 Slider::~Slider() {
-  abort_load_thumbnail = true;
-  thumnail_future.waitForFinished();
+  abort_parse_qlog = true;
+  if (qlog_future) {
+    qlog_future->waitForFinished();
+  }
 }
 
-void Slider::loadThumbnails() {
+void Slider::parseQLog() {
   const auto &segments = can->route()->segments();
-  double max_time = 0;
-  for (auto it = segments.rbegin(); it != segments.rend() && !abort_load_thumbnail; ++it) {
+  for (auto it = segments.rbegin(); it != segments.rend() && !abort_parse_qlog; ++it) {
     LogReader log;
     std::string qlog = it->second.qlog.toStdString();
-    if (!qlog.empty() && log.load(qlog, &abort_load_thumbnail, {cereal::Event::Which::THUMBNAIL, cereal::Event::Which::CONTROLS_STATE}, true, 0, 3)) {
-      if (max_time == 0 && !log.events.empty()) {
-        max_time = (*(log.events.rbegin()))->mono_time / 1e9 - can->routeStartTime();
+    if (!qlog.empty() && log.load(qlog, &abort_parse_qlog, {cereal::Event::Which::THUMBNAIL, cereal::Event::Which::CONTROLS_STATE}, true, 0, 3)) {
+      if (it == segments.rbegin() && !log.events.empty()) {
+        double max_time = (*(log.events.rbegin()))->mono_time / 1e9 - can->routeStartTime();
         emit updateMaximumTime(max_time);
       }
-      for (auto ev = log.events.cbegin(); ev != log.events.cend() && !abort_load_thumbnail; ++ev) {
+      for (auto ev = log.events.cbegin(); ev != log.events.cend() && !abort_parse_qlog; ++ev) {
         if ((*ev)->which == cereal::Event::Which::THUMBNAIL) {
           auto thumb = (*ev)->event.getThumbnail();
           auto data = thumb.getThumbnail();

tools/cabana/videowidget.h

@@ -44,16 +44,16 @@ private:
   bool event(QEvent *event) override;
   void sliderChange(QAbstractSlider::SliderChange change) override;
   void paintEvent(QPaintEvent *ev) override;
-  void loadThumbnails();
+  void parseQLog();
 
   double max_sec = 0;
   int slider_x = -1;
   std::vector<std::tuple<int, int, TimelineType>> timeline;
   std::mutex thumbnail_lock;
-  std::atomic<bool> abort_load_thumbnail = false;
+  std::atomic<bool> abort_parse_qlog = false;
   QMap<uint64_t, QPixmap> thumbnails;
   std::map<uint64_t, AlertInfo> alerts;
-  QFuture<void> thumnail_future;
+  std::unique_ptr<QFuture<void>> qlog_future;
   InfoLabel thumbnail_label;
   friend class VideoWidget;
 };