bndtools#5062 JVM Crash in bndtools explorer

I was able to consistently crash the VM by
selecting a binary class file in rt.jar from
the VM project item and then closing the VM project
item.

After hundreds of trials I found that the bug was
triggered when the getTreeViewer().refresh() was
called during a model update. For the record,
this happened on the main thread so I cannot
see any issue with this.

I then made the refresh conditional on a change
in the filter text field. For this, an
AtomicBoolean dirtyFilter was added.

This seemed to work fine now.

Of course this does not remove the bug. There
is an SWT bug lurking but closing an tree item
in the bnd explorer will no longer trigger it.



Signed-off-by: Peter Kriens <Peter.Kriens@aqute.biz>

bndtools.core/src/bndtools/Plugin.java

@@ -70,7 +70,7 @@ public void start(BundleContext context) throws Exception {
 		plugin = this;
 		this.bundleContext = context;
 
-		scheduler = Executors.newScheduledThreadPool(1);
+		scheduler = Executors.newScheduledThreadPool(4);
 
 		bndActivator = new Activator();
 		bndActivator.start(context);

bndtools.core/src/bndtools/explorer/BndtoolsExplorer.java

@@ -336,9 +336,11 @@ private void updateTreeViewer() {
 		if (!installed) {
 			installed = true;
 			installFilter();
+			model.filterDirty.set(true);
 		}
 
-		getTreeViewer().refresh();
+		if (model.filterDirty.getAndSet(false))
+			getTreeViewer().refresh();
 	}
 
 	private void installFilter() {

bndtools.core/src/bndtools/explorer/Model.java

@@ -24,6 +24,7 @@ class Model {
 	String					message	= "initializing workspace";
 	int						severity;
 	String					filterText;
+	final AtomicBoolean		filterDirty	= new AtomicBoolean(false);
 	final List<Runnable>	updates	= new ArrayList<>();
 	final AtomicBoolean		dirty	= new AtomicBoolean(false);
 	final Set<IProject>		pinned	= new HashSet<>();
@@ -48,6 +49,7 @@ void setFilterText(String value) {
 			glob = null;
 		else
 			glob = new Glob(value);
+		filterDirty.set(true);
 		update();
 	}
 
@@ -77,14 +79,15 @@ void updateMessage() {
 	void setSeverity(int severity) {
 		if (this.severity != severity) {
 			this.severity = severity;
+			filterDirty.set(true);
 			update();
 		}
 	}
 
 	private String getPrompt(Workspace ws) {
 		try {
 			if (prompt == null || prompt.isEmpty())
-				prompt = "<b>${basename;${workspace}}</b> ${def;Bundle-Version} <a href='prefs'>change macro def</a>";
+				prompt = "<b>${basename;${workspace}}</b> ${def;Bundle-Version} <a href='prefs'>[?]</a>";
 			else if ("-".equals(prompt))
 				return "";
 
@@ -113,16 +116,6 @@ void update() {
 	 * This runs async on the display thread.
 	 */
 	private void update0() {
-		try {
-			// coalesce some more updates on
-			// the worker thread(s).
-			Thread.sleep(50);
-		} catch (InterruptedException e) {
-			Thread.currentThread()
-				.interrupt();
-			return;
-		}
-
 		if (dirty.getAndSet(false)) {
 			updates.forEach(Runnable::run);
 		}
@@ -138,6 +131,7 @@ void doPin() {
 		} else {
 			pinned.add(p);
 		}
+		filterDirty.set(true);
 		update();
 	}