From ae2d1ae853d5232df4337e4b2c417a9d57e11aa7 Mon Sep 17 00:00:00 2001
From: Fabian Stemmler <stemmler@in.tum.de>
Date: Sat, 28 Sep 2019 14:41:27 +0200
Subject: [PATCH] Fixed issue with row highlighting

Too many highlight requests were being sent to the SWT Eventqueue when
running the simulation at a faster speed. Now there can be at most one
such request at the same time.
---
 .../plugin/tables/mi/InstructionView.java     | 19 ++-----
 .../plugin/tables/mi/RowHighlighter.java      | 54 +++++++++++++++++++
 2 files changed, 57 insertions(+), 16 deletions(-)
 create mode 100644 plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/tables/mi/RowHighlighter.java

diff --git a/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/tables/mi/InstructionView.java b/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/tables/mi/InstructionView.java
index 0158c7bb..7a692c94 100644
--- a/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/tables/mi/InstructionView.java
+++ b/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/tables/mi/InstructionView.java
@@ -11,7 +11,6 @@ import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Composite;
-import org.eclipse.swt.widgets.Display;
 import org.eclipse.ui.IEditorInput;
 import org.eclipse.ui.IEditorSite;
 import org.eclipse.ui.IFileEditorInput;
@@ -27,17 +26,16 @@ import net.mograsim.machine.mi.MicroInstructionMemoryParser;
 import net.mograsim.plugin.nature.MachineContext;
 import net.mograsim.plugin.nature.ProjectMachineContext;
 import net.mograsim.plugin.tables.DisplaySettings;
-import net.mograsim.plugin.tables.LazyTableViewer;
 import net.mograsim.plugin.tables.RadixSelector;
 
 public class InstructionView extends EditorPart implements MemoryCellModifiedListener, ActiveMicroInstructionChangedListener
 {
 	private InstructionTableContentProvider provider;
-	private int highlighted = 0;
 	private boolean dirty = false;
 	private MicroInstructionMemory memory;
 	private InstructionTable table;
 	private MachineContext context;
+	private RowHighlighter highlighter;
 
 	@SuppressWarnings("unused")
 	@Override
@@ -58,23 +56,12 @@ public class InstructionView extends EditorPart implements MemoryCellModifiedLis
 		GridData viewerData = new GridData(GridData.GRAB_HORIZONTAL | GridData.GRAB_VERTICAL | GridData.FILL_BOTH);
 		viewerData.horizontalSpan = 3;
 		table.getTableViewer().getTable().setLayoutData(viewerData);
+		highlighter = new RowHighlighter(table.getTableViewer());
 	}
 
 	public void highlight(int index)
 	{
-		Display.getDefault().asyncExec(() ->
-		{
-			LazyTableViewer viewer = table.getTableViewer();
-			viewer.highlightRow(highlighted, false);
-			highlighted = index;
-			if (index != -1)
-			{
-				viewer.highlightRow(index, true);
-				viewer.getTable()
-						.showItem(viewer.getTable().getItem(Math.min((int) memory.getDefinition().getMaximalAddress(), index + 2)));
-				viewer.getTable().showItem(viewer.getTable().getItem(index));
-			}
-		});
+		highlighter.highlight(index);
 	}
 
 	private void addActivationButton(Composite parent)
diff --git a/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/tables/mi/RowHighlighter.java b/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/tables/mi/RowHighlighter.java
new file mode 100644
index 00000000..18e01084
--- /dev/null
+++ b/plugins/net.mograsim.plugin.core/src/net/mograsim/plugin/tables/mi/RowHighlighter.java
@@ -0,0 +1,54 @@
+package net.mograsim.plugin.tables.mi;
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import org.eclipse.swt.widgets.Display;
+import org.eclipse.swt.widgets.Table;
+
+import net.mograsim.plugin.tables.LazyTableViewer;
+
+public class RowHighlighter
+{
+	private int highlighted, toHighlight;
+	private LazyTableViewer viewer;
+	private AtomicBoolean waiting = new AtomicBoolean();
+
+	public RowHighlighter(LazyTableViewer viewer)
+	{
+		this.viewer = viewer;
+	}
+
+	public void highlight(int row)
+	{
+		synchronized (waiting)
+		{
+			toHighlight = row;
+			if (!waiting.get())
+			{
+				waiting.set(true);
+				Display.getDefault().asyncExec(() ->
+				{
+					synchronized (waiting)
+					{
+						waiting.set(false);
+						if (!viewer.getTable().isDisposed())
+							innerHighlight(toHighlight);
+					}
+				});
+			}
+		}
+	}
+
+	private void innerHighlight(int row)
+	{
+		viewer.highlightRow(highlighted, false);
+		highlighted = row;
+		if (row != -1)
+		{
+			viewer.highlightRow(row, true);
+			Table table = viewer.getTable();
+			table.showItem(table.getItem(Math.min(table.getItemCount(), row + 2)));
+			table.showItem(table.getItem(row));
+		}
+	}
+}
-- 
2.17.1