Refs #3348: Thread-safe progress updates when rebinning in PV.

Code/Mantid/Vates/ParaviewPlugins/ParaViewReaders/EventNexusReader/vtkEventNexusReader.cxx

@@ -543,6 +543,8 @@ unsigned long vtkEventNexusReader::GetMTime()
 */
 void vtkEventNexusReader::UpdateAlgorithmProgress(double progress)
 {
+  progressMutex.lock();
   this->SetProgressText("Executing Mantid MDEvent Rebinning Algorithm...");
   this->UpdateProgress(progress);
+  progressMutex.unlock();
 }

Code/Mantid/Vates/ParaviewPlugins/ParaViewReaders/EventNexusReader/vtkEventNexusReader.h

@@ -6,6 +6,7 @@
 #include "MantidVatesAPI/EscalatingRebinningActionManager.h"
 #include "MantidGeometry/MDGeometry/MDGeometryXMLBuilder.h"
 #include "MantidVatesAPI/ThresholdRange.h"
+#include "MantidKernel/MultiThreaded.h"
 
 class vtkImplicitFunction;
 class VTK_EXPORT vtkEventNexusReader : public vtkUnstructuredGridAlgorithm
@@ -156,5 +157,8 @@ private:
   int m_thresholdMethodIndex;
 
   Mantid::VATES::ThresholdRange_scptr m_ThresholdRange;
+
+  /// Mutex for thread-safe progress reporting.
+  Mantid::Kernel::Mutex progressMutex;
 };
 #endif