CtfVisualizer: Do not crash on unexpected types again

And print a nicer error message.

Amends c05f9cacc6

Task-number: QTCREATORBUG-29659
Change-Id: I1db6bea0bedf1fae034fecbbbeae56bb2fee49ed
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/ctfvisualizer/ctftracemanager.cpp

@@ -46,6 +46,7 @@ qint64 CtfTraceManager::traceEnd() const
 
 void CtfTraceManager::addEvent(const json &event)
 {
+    try {
         const double timestamp = event.value(CtfTracingClockTimestampKey, -1.0);
         if (timestamp < 0) {
             // events without or with negative timestamp will be ignored
@@ -56,7 +57,8 @@ void CtfTraceManager::addEvent(const json &event)
             m_timeOffset = timestamp;
         }
 
-    static const auto getStringValue = [](const json &event, const char *key, const QString &def) {
+        static const auto getStringValue =
+            [](const json &event, const char *key, const QString &def) {
                 if (!event.contains(key))
                     return def;
                 const json val = event[key];
@@ -91,6 +93,10 @@ void CtfTraceManager::addEvent(const json &event)
             // -> reset the time offset again:
             m_timeOffset = -1.0;
         }
+    } catch (...) {
+        m_errorString = Tr::tr("Error while parsing CTF data: %1.")
+                            .arg("<pre>" + QString::fromStdString(event.dump()) + "</pre>");
+    }
 }
 
 void CtfTraceManager::finalize()
@@ -216,6 +222,7 @@ void CtfTraceManager::updateStatistics()
 
 void CtfTraceManager::clearAll()
 {
+    m_errorString.clear();
     m_modelAggregator->clear();
     for (CtfTimelineModel *model: std::as_const(m_threadModels)) {
         model->deleteLater();
@@ -226,6 +233,10 @@ void CtfTraceManager::clearAll()
     m_timeOffset = -1;
 }
 
+QString CtfTraceManager::errorString() const
+{
+    return m_errorString;
+}
 
 } // namespace Internal
 } // namespace CtfVisualizer

src/plugins/ctfvisualizer/ctftracemanager.h

@@ -46,6 +46,8 @@ public:
     void updateStatistics();
     void clearAll();
 
+    QString errorString() const;
+
 signals:
     void detailsRequested(const QString &title);
 
@@ -66,6 +68,7 @@ protected:
     double m_traceEnd = std::numeric_limits<double>::min();
     double m_timeOffset = -1.0;
 
+    QString m_errorString;
 };
 
 } // namespace Internal

src/plugins/ctfvisualizer/ctfvisualizertool.cpp

@@ -231,6 +231,10 @@ void CtfVisualizerTool::loadJson(const QString &fileName)
             QMessageBox::warning(Core::ICore::dialogParent(),
                                  Tr::tr("CTF Visualizer"),
                                  Tr::tr("The file does not contain any trace data."));
+        } else if (!m_traceManager->errorString().isEmpty()) {
+            QMessageBox::warning(Core::ICore::dialogParent(),
+                                 Tr::tr("CTF Visualizer"),
+                                 m_traceManager->errorString());
         } else {
             m_traceManager->finalize();
             m_perspective.select();