timing: Fix SegmentStoreScatterDataProvider for empty segment store

For example, if a trace doesn't have any call stack events to populate
the segment store and hence populate the view, the data provider should
return an empty model instead of failed for fetchTree and fetchXy

[Fixed] Fix SegmentStoreScatterDataProvider for empty segment store

Signed-off-by: Bernd Hufmann <[email protected]>

Author: bhufmann

analysis/org.eclipse.tracecompass.analysis.timing.core/src/org/eclipse/tracecompass/internal/analysis/timing/core/segmentstore/SegmentStoreScatterDataProvider.java

@@ -254,18 +254,22 @@ private SegmentStoreScatterDataProvider(ITmfTrace trace, ISegmentStoreProvider p
     @Override
     public TmfModelResponse<TmfTreeModel<TmfTreeDataModel>> fetchTree(Map<String, Object> fetchParameters, @Nullable IProgressMonitor monitor) {
         ISegmentStoreProvider provider = fProvider;
+        boolean waitResult = true;
         if (provider instanceof IAnalysisModule) {
             IAnalysisModule module = (IAnalysisModule) provider;
             IProgressMonitor mon = monitor != null ? monitor : new NullProgressMonitor();
-            module.waitForCompletion(mon);
+            waitResult = module.waitForCompletion(mon);
             if (mon.isCanceled()) {
                 return new TmfModelResponse<>(null, Status.CANCELLED, CommonStatusMessage.TASK_CANCELLED);
             }
         }
         ISegmentStore<ISegment> segStore = provider.getSegmentStore();
 
         if (segStore == null) {
-            return new TmfModelResponse<>(null, ITmfResponse.Status.FAILED, CommonStatusMessage.ANALYSIS_INITIALIZATION_FAILED);
+            if (!waitResult) {
+                return new TmfModelResponse<>(null, ITmfResponse.Status.FAILED, CommonStatusMessage.ANALYSIS_INITIALIZATION_FAILED);
+            }
+            return new TmfModelResponse<>(new TmfTreeModel<>(Collections.emptyList(), Collections.emptyList()), ITmfResponse.Status.COMPLETED, CommonStatusMessage.COMPLETED);
         }
         TimeQueryFilter filter = FetchParametersUtils.createTimeQuery(fetchParameters);
         if (filter == null) {
@@ -333,8 +337,10 @@ public TmfModelResponse<ITmfXyModel> fetchXY(Map<String, Object> fetchParameters
         }
 
         final ISegmentStore<ISegment> segStore = provider.getSegmentStore();
+
         if (segStore == null) {
-            return TmfXyResponseFactory.createFailedResponse(Objects.requireNonNull(Messages.SegmentStoreDataProvider_SegmentNotAvailable));
+            return TmfXyResponseFactory.create(Objects.requireNonNull(Messages.SegmentStoreScatterGraphViewer_title),
+                    Collections.emptyList(), true);
         }
 
         // TODO server: Parameters validation should be handle separately. It