Refs #4641 thread-safe QwtPlot replacement

Also refs #4516, using this safeqwtPlot in SliceViewer looks to make it impossible to segfault

Code/Mantid/MantidQt/API/CMakeLists.txt

@@ -9,6 +9,7 @@ set ( SRC_FILES
 	src/MantidDialog.cpp
 	src/MantidWidget.cpp
 	src/PythonRunner.cpp
+	src/SafeQwtPlot.cpp
 	src/SyncedCheckboxes.cpp
 	src/UserSubWindow.cpp
 	src/VatesViewerInterface.cpp
@@ -30,6 +31,7 @@ set ( INC_FILES
 	inc/MantidQtAPI/MantidDialog.h
 	inc/MantidQtAPI/MantidWidget.h
 	inc/MantidQtAPI/PythonRunner.h
+	inc/MantidQtAPI/SafeQwtPlot.h
 	inc/MantidQtAPI/SyncedCheckboxes.h
 	inc/MantidQtAPI/UserSubWindow.h
 	inc/MantidQtAPI/VatesViewerInterface.h

Code/Mantid/MantidQt/API/inc/MantidQtAPI/SafeQwtPlot.h

@@ -0,0 +1,65 @@
+#ifndef MANTID_API_SAFEQWTPLOT_H_
+#define MANTID_API_SAFEQWTPLOT_H_
+
+#include "MantidKernel/System.h"
+#include <qwt_plot.h>
+#include <qpainter.h>
+#include "qwt_text.h"
+#include "MantidAPI/Workspace.h"
+
+
+namespace MantidQt
+{
+namespace API
+{
+
+  /** A version of QwtPlot that adds a layer of thread safety.
+   * Each SafeQwtPlot has a workspace associated with it.
+   * Before drawing, it acquires a ReadLock to prevent
+   * an algorithm from modifying the underlying workspace while it is
+   * drawing.
+    
+    @date 2012-01-24
+
+    Copyright &copy; 2012 ISIS Rutherford Appleton Laboratory & NScD Oak Ridge National Laboratory
+
+    This file is part of Mantid.
+
+    Mantid is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    Mantid is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+    File change history is stored at: <https://svn.mantidproject.org/mantid/trunk/Code/Mantid>
+    Code Documentation is available at: <http://doxygen.mantidproject.org>
+  */
+  class DLLExport SafeQwtPlot : public QwtPlot
+  {
+  public:
+    explicit SafeQwtPlot(QWidget * parent = NULL);
+    explicit SafeQwtPlot(const QwtText &title, QWidget *p = NULL);
+
+    virtual ~SafeQwtPlot();
+
+    virtual void drawCanvas(QPainter * painter);
+
+    void setWorkspace(Mantid::API::Workspace_sptr ws);
+
+  private:
+    /// Workspace being read-locked
+    Mantid::API::Workspace_sptr m_ws;
+  };
+
+
+} // namespace API
+} // namespace MantidQt
+
+#endif  /* MANTID_API_SAFEQWTPLOT_H_ */

Code/Mantid/MantidQt/API/src/SafeQwtPlot.cpp

@@ -0,0 +1,65 @@
+#include "MantidQtAPI/SafeQwtPlot.h"
+#include "MantidKernel/System.h"
+#include "MantidKernel/ReadLock.h"
+
+using namespace Mantid::Kernel;
+
+namespace MantidQt
+{
+namespace API
+{
+
+
+  //----------------------------------------------------------------------------------------------
+  /** Constructor
+   */
+  SafeQwtPlot::SafeQwtPlot(QWidget * parent)
+  : QwtPlot(parent)
+  {
+  }
+
+
+  //----------------------------------------------------------------------------------------------
+  /** Constructor
+   */
+  SafeQwtPlot::SafeQwtPlot(const QwtText &title, QWidget * parent)
+  : QwtPlot(title, parent)
+  {
+  }
+
+  //----------------------------------------------------------------------------------------------
+  /** Destructor
+   */
+  SafeQwtPlot::~SafeQwtPlot()
+  {
+  }
+
+
+  //----------------------------------------------------------------------------------------------
+  /** Set the workspace that we read-lock when drawing.
+   *
+   * @param ws :: shared ptr to workspace
+   */
+  void SafeQwtPlot::setWorkspace(Mantid::API::Workspace_sptr ws)
+  {
+    m_ws = ws;
+  }
+
+  //----------------------------------------------------------------------------------------------
+  /** Overridden drawCanvas() that protects the
+   * workspace from being overwritten while being drawn
+   *
+   * @param painter :: QPainter
+   */
+  void SafeQwtPlot::drawCanvas(QPainter * painter)
+  {
+    // Do nothing if the workspace is not valid.
+    if (!m_ws) return;
+    // Get the scoped read lock.
+    ReadLock lock(*m_ws);
+    // Draw using the usual procedure.
+    QwtPlot::drawCanvas(painter);
+  }
+
+} // namespace MantidQt
+} // namespace API

Code/Mantid/MantidQt/SliceViewer/inc/MantidQtSliceViewer/SliceViewer.h

@@ -9,6 +9,7 @@
 #include "MantidGeometry/MDGeometry/MDHistoDimension.h"
 #include "MantidKernel/VMD.h"
 #include "MantidQtAPI/MantidColorMap.h"
+#include "MantidQtAPI/SafeQwtPlot.h"
 #include "MantidQtAPI/SyncedCheckboxes.h"
 #include "MantidQtSliceViewer/LineOverlay.h"
 #include "QwtRasterDataMD.h"
@@ -135,7 +136,7 @@ public slots:
   Ui::SliceViewerClass ui;
 
   /// Main plot object
-  QwtPlot * m_plot;
+  MantidQt::API::SafeQwtPlot * m_plot;
 
   /// Spectrogram plot
   QwtPlotSpectrogram * m_spect;

Code/Mantid/MantidQt/SliceViewer/src/SliceViewer.cpp

@@ -49,6 +49,7 @@
 #include <vector>
 #include "MantidKernel/V3D.h"
 #include "MantidKernel/ReadLock.h"
+#include "MantidQtAPI/SafeQwtPlot.h"
 
 
 using namespace Mantid;
@@ -63,6 +64,7 @@ using Poco::XML::Node;
 using Poco::XML::NodeList;
 using Poco::XML::NodeIterator;
 using Poco::XML::NodeFilter;
+using MantidQt::API::SafeQwtPlot;
 
 namespace MantidQt
 {
@@ -86,7 +88,7 @@ SliceViewer::SliceViewer(QWidget *parent)
 
 	// Create the plot
   m_spectLayout = new QHBoxLayout(ui.frmPlot);
-	m_plot = new QwtPlot();
+	m_plot = new SafeQwtPlot();
   m_plot->autoRefresh();
   m_spectLayout->addWidget(m_plot, 1, 0);
 
@@ -424,6 +426,7 @@ void SliceViewer::setWorkspace(Mantid::API::IMDWorkspace_sptr ws)
 {
   m_ws = ws;
   m_data->setWorkspace(ws);
+  m_plot->setWorkspace(ws);
 
   // Emit the signal that we changed the workspace
   emit workspaceChanged();