tmf: Fix NullPointerExeptions in Histogram view

These NPEs happens when clicking or dragging the mouse in the
histogram windows before any data is available in the scaled data
instance.

Change-Id: I57efdb03cd53e2198580fa6c0ed047fc2dc4c3ac
Signed-off-by: Bernd Hufmann <Bernd.Hufmann@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/19268
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>
IP-Clean: Patrick Tasse <patrick.tasse@gmail.com>
Tested-by: Hudson CI

3 files changed, 7 insertions, 3 deletions

diff --git a/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/FullTraceHistogram.java b/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/FullTraceHistogram.java
index 12d7a29a5c..ebb16cba99 100644
--- a/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/FullTraceHistogram.java
+++ b/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/FullTraceHistogram.java
@@ -108,7 +108,7 @@ public class FullTraceHistogram extends Histogram {
 
     @Override
     public void mouseDown(MouseEvent event) {
-        if (fDragState == DRAG_NONE && fDataModel.getNbEvents() != 0) {
+        if (fScaledData != null && fDragState == DRAG_NONE && fDataModel.getNbEvents() != 0) {
             if (event.button == 2 || (event.button == 1 && (event.stateMask & SWT.MODIFIER_MASK) == SWT.CTRL)) {
                 fDragState = DRAG_RANGE;
                 fDragButton = event.button;
diff --git a/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/Histogram.java b/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/Histogram.java
index 823789c4fa..b2882d7ea1 100644
--- a/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/Histogram.java
+++ b/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/Histogram.java
@@ -778,6 +778,10 @@ public abstract class Histogram implements ControlListener, PaintListener, KeyLi
      */
     protected void drawTimeRangeWindow(GC imageGC, long rangeStartTime, long rangeDuration) {
 
+        if (fScaledData == null) {
+            return;
+        }
+
         // Map times to histogram coordinates
         long bucketSpan = Math.max(fScaledData.fBucketDuration, 1);
         long startTime = Math.min(rangeStartTime, rangeStartTime + rangeDuration);
@@ -834,7 +838,7 @@ public abstract class Histogram implements ControlListener, PaintListener, KeyLi
 
     @Override
     public void mouseDown(final MouseEvent event) {
-        if (event.button == 1 && fDragState == DRAG_NONE && fDataModel.getNbEvents() != 0) {
+        if (fScaledData != null && event.button == 1 && fDragState == DRAG_NONE && fDataModel.getNbEvents() != 0) {
             fDragState = DRAG_SELECTION;
             fDragButton = event.button;
             if ((event.stateMask & SWT.MODIFIER_MASK) == SWT.SHIFT) {
diff --git a/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/TimeRangeHistogram.java b/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/TimeRangeHistogram.java
index e5d5b22b4c..04b99e932e 100644
--- a/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/TimeRangeHistogram.java
+++ b/lttng/org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/views/histogram/TimeRangeHistogram.java
@@ -114,7 +114,7 @@ public class TimeRangeHistogram extends Histogram {
 
     @Override
     public void mouseDown(MouseEvent event) {
-        if (fDragState == DRAG_NONE && fDataModel.getNbEvents() != 0) {
+        if (fScaledData != null && fDragState == DRAG_NONE && fDataModel.getNbEvents() != 0) {
             if (event.button == 2 || (event.button == 1 && (event.stateMask & SWT.MODIFIER_MASK) == SWT.CTRL)) {
                 fDragState = DRAG_RANGE;
                 fDragButton = event.button;