GP-0: Various UI test fixes, incl. viewport syncing

GP-0: Fixed Listing tests wrt/ location label

GP-0: Trying to synchronize view creation and memory layout

GP-0: Trying to fix CME

GP-0: Got viewport synchronized, and it resolved test.

GP-0: Fixing regions tests - involved listing selections

GP-0: Fixed modules/sections provider tests

GP-0: Fixed static-mappings provider tests.

Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/gui/listing/DebuggerListingPlugin.java

@@ -180,7 +180,6 @@ public class DebuggerListingPlugin extends CodeBrowserPlugin implements Debugger
 		actionNewListing = new NewListingAction();
 	}
 
-	@Override
 	public DebuggerListingProvider createListingIfMissing(LocationTrackingSpec spec,
 			boolean followsCurrentThread) {
 		synchronized (disconnectedProviders) {
@@ -331,7 +330,7 @@ public class DebuggerListingPlugin extends CodeBrowserPlugin implements Debugger
 
 	@Override
 	public void setCurrentSelection(ProgramSelection selection) {
-		getListingPanel().setSelection(selection);
+		getConnectedProvider().setSelection(selection);
 	}
 
 	@Override

Ghidra/Debug/Debugger/src/main/java/ghidra/app/plugin/core/debug/gui/modules/DebuggerModulesProvider.java

@@ -454,7 +454,7 @@ public class DebuggerModulesProvider extends ComponentProviderAdapter {
 				return;
 			}
 			Set<TraceModule> modules = getSelectedModules(myActionContext);
-			if (modules.size() != 1) {
+			if (modules == null || modules.size() != 1) {
 				return;
 			}
 			TraceModule mod = modules.iterator().next();

Ghidra/Debug/Debugger/src/main/java/ghidra/app/services/DebuggerListingService.java

@@ -16,19 +16,16 @@
 package ghidra.app.services;
 
 import ghidra.app.plugin.core.debug.gui.action.LocationTrackingSpec;
-import ghidra.app.plugin.core.debug.gui.listing.*;
+import ghidra.app.plugin.core.debug.gui.listing.DebuggerListingPlugin;
 import ghidra.framework.plugintool.ServiceInfo;
 import ghidra.program.model.address.Address;
 import ghidra.program.util.ProgramSelection;
 
 @ServiceInfo( //
-		defaultProvider = DebuggerListingPlugin.class, //
-		description = "Replacement CodeViewerService for Debugger" //
+	defaultProvider = DebuggerListingPlugin.class, //
+	description = "Replacement CodeViewerService for Debugger" //
 )
 public interface DebuggerListingService extends CodeViewerService {
-	@Deprecated
-	DebuggerListingProvider createListingIfMissing(LocationTrackingSpec spec,
-			boolean followsCurrentThread);
 
 	void setTrackingSpec(LocationTrackingSpec spec);
 

Ghidra/Debug/Debugger/src/test/java/ghidra/app/plugin/core/debug/gui/listing/DebuggerListingProviderTest.java

@@ -743,15 +743,13 @@ public class DebuggerListingProviderTest extends AbstractGhidraHeadedDebuggerGUI
 		traceManager.activateTrace(tb.trace);
 		waitForSwing();
 		assertEquals(traceManager.getCurrentView(), listingProvider.getProgram());
-		assertEquals("dynamic-testCloseCurrentTraceBlanksListings",
-			listingProvider.locationLabel.getText());
+		assertEquals("(nowhere)", listingProvider.locationLabel.getText());
 
 		DebuggerListingProvider extraProvider = runSwing(
 			() -> listingPlugin.createListingIfMissing(trackNone, false));
 		waitForSwing();
 		assertEquals(traceManager.getCurrentView(), extraProvider.getProgram());
-		assertEquals("dynamic-testCloseCurrentTraceBlanksListings",
-			extraProvider.locationLabel.getText());
+		assertEquals("(nowhere)", extraProvider.locationLabel.getText());
 
 		traceManager.closeTrace(tb.trace);
 		waitForSwing();
@@ -1140,26 +1138,30 @@ public class DebuggerListingProviderTest extends AbstractGhidraHeadedDebuggerGUI
 
 		traceManager.activateTrace(tb.trace);
 		waitForSwing();
-		assertEquals("dynamic-testLocationLabel", listingProvider.locationLabel.getText());
+		assertEquals("(nowhere)", listingProvider.locationLabel.getText());
 
 		try (UndoableTransaction tid = tb.startTransaction()) {
 			tb.trace.getMemoryManager()
-					.addRegion("exe:.text", Range.atLeast(0L), tb.range(0x55550000, 0x555500ff),
+					.addRegion("test_region", Range.atLeast(0L), tb.range(0x55550000, 0x555502ff),
 						TraceMemoryFlag.READ, TraceMemoryFlag.EXECUTE);
 		}
 		waitForDomainObject(tb.trace);
-		waitForPass(() -> assertEquals("dynamic-testLocationLabel (exe:.text)",
-			listingProvider.locationLabel.getText()));
+		waitForPass(() -> assertEquals("test_region", listingProvider.locationLabel.getText()));
+
+		TraceModule modExe;
+		try (UndoableTransaction tid = tb.startTransaction()) {
+			modExe = tb.trace.getModuleManager()
+					.addModule("modExe", "modExe",
+						tb.range(0x55550000, 0x555501ff), Range.atLeast(0L));
+		}
+		waitForDomainObject(tb.trace);
+		waitForPass(() -> assertEquals("modExe", listingProvider.locationLabel.getText()));
 
 		try (UndoableTransaction tid = tb.startTransaction()) {
-			TraceModule modExe = tb.trace.getModuleManager()
-					.addModule("modExe", "modExe",
-						tb.range(0x55550000, 0x555500ff), Range.atLeast(0L));
 			modExe.addSection(".text", tb.range(0x55550000, 0x555500ff));
 		}
 		waitForDomainObject(tb.trace);
-		waitForPass(() -> assertEquals("dynamic-testLocationLabel (modExe:.text)",
-			listingProvider.locationLabel.getText()));
+		waitForPass(() -> assertEquals("modExe:.text", listingProvider.locationLabel.getText()));
 	}
 
 	@Test

Ghidra/Debug/Debugger/src/test/java/ghidra/app/plugin/core/debug/gui/memory/DebuggerRegionsProviderTest.java

@@ -15,12 +15,12 @@
  */
 package ghidra.app.plugin.core.debug.gui.memory;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.*;
 
 import java.util.Set;
 
-import org.junit.*;
+import org.junit.Before;
+import org.junit.Test;
 
 import com.google.common.collect.Range;
 
@@ -186,6 +186,7 @@ public class DebuggerRegionsProviderTest extends AbstractGhidraHeadedDebuggerGUI
 		traceManager.openTrace(tb.trace);
 		traceManager.activateTrace(tb.trace);
 		waitForSwing();
+		waitForPass(() -> assertEquals(1, provider.regionTable.getRowCount()));
 
 		RegionRow row = Unique.assertOne(provider.regionTableModel.getModelData());
 		assertEquals(region, row.getRegion());
@@ -198,7 +199,6 @@ public class DebuggerRegionsProviderTest extends AbstractGhidraHeadedDebuggerGUI
 	}
 
 	@Test
-	@Ignore("TODO: Seems the error is in the listing")
 	public void testActionSelectAddresses() throws Exception {
 		addPlugin(tool, DebuggerListingPlugin.class);
 		DebuggerListingProvider listing = waitForComponentProvider(DebuggerListingProvider.class);
@@ -217,16 +217,17 @@ public class DebuggerRegionsProviderTest extends AbstractGhidraHeadedDebuggerGUI
 		waitForSwing();
 
 		RegionRow row = Unique.assertOne(provider.regionTableModel.getModelData());
+		waitForPass(() -> assertEquals(1, provider.regionTable.getRowCount()));
 		assertEquals(region, row.getRegion());
+		assertFalse(tb.trace.getProgramView().getMemory().isEmpty());
 
 		provider.setSelectedRegions(Set.of(region));
 		waitForSwing();
 		assertTrue(provider.actionSelectAddresses.isEnabled());
 		performAction(provider.actionSelectAddresses);
 
-		// TODO: This seems to me an error in the listing....
-		// When debugging, I see the selection in the listing, but this still returns empty...
-		assertEquals(tb.range(0x00400000, 0x0040ffff), new AddressSet(listing.getSelection()));
+		waitForPass(() -> assertEquals(tb.set(tb.range(0x00400000, 0x0040ffff)),
+			new AddressSet(listing.getSelection())));
 	}
 
 	@Test
@@ -249,12 +250,16 @@ public class DebuggerRegionsProviderTest extends AbstractGhidraHeadedDebuggerGUI
 
 		RegionRow row = Unique.assertOne(provider.regionTableModel.getModelData());
 		assertEquals(region, row.getRegion());
+		assertFalse(tb.trace.getProgramView().getMemory().isEmpty());
 
 		listing.setSelection(new ProgramSelection(tb.set(tb.range(0x00401234, 0x00404321))));
+		waitForPass(() -> assertEquals(tb.set(tb.range(0x00401234, 0x00404321)),
+			new AddressSet(listing.getSelection())));
+
 		waitForSwing();
 		assertTrue(provider.actionSelectRows.isEnabled());
 		performAction(provider.actionSelectRows);
 
-		assertEquals(Set.of(row), Set.copyOf(provider.getSelectedRows()));
+		waitForPass(() -> assertEquals(Set.of(row), Set.copyOf(provider.getSelectedRows())));
 	}
 }

Ghidra/Debug/Debugger/src/test/java/ghidra/app/plugin/core/debug/gui/modules/DebuggerModulesProviderTest.java

@@ -222,6 +222,7 @@ public class DebuggerModulesProviderTest extends AbstractGhidraHeadedDebuggerGUI
 			program.setName(modExe.getName());
 		}
 		waitForDomainObject(program);
+		waitForPass(() -> assertEquals(4, modulesProvider.sectionTable.getRowCount()));
 
 		modulesProvider.setSelectedSections(Set.of(secExeText));
 		performAction(modulesProvider.actionMapSections, false);
@@ -349,6 +350,7 @@ public class DebuggerModulesProviderTest extends AbstractGhidraHeadedDebuggerGUI
 			addBlock(); // So the program has a size
 		}
 		waitForDomainObject(program);
+		waitForPass(() -> assertEquals(2, modulesProvider.moduleTable.getRowCount()));
 
 		modulesProvider.setSelectedModules(Set.of(modExe));
 		waitForSwing();
@@ -411,6 +413,7 @@ public class DebuggerModulesProviderTest extends AbstractGhidraHeadedDebuggerGUI
 			program.setName(modExe.getName());
 		}
 		waitForDomainObject(program);
+		waitForPass(() -> assertEquals(4, modulesProvider.sectionTable.getRowCount()));
 
 		modulesProvider.setSelectedSections(Set.of(secExeText));
 		waitForSwing();
@@ -470,6 +473,8 @@ public class DebuggerModulesProviderTest extends AbstractGhidraHeadedDebuggerGUI
 
 		traceManager.activateTrace(tb.trace);
 		waitForSwing(); // NOTE: The table may select first by default, enabling action
+		waitForPass(() -> assertEquals(2, modulesProvider.moduleTable.getRowCount()));
+		waitForPass(() -> assertEquals(4, modulesProvider.sectionTable.getRowCount()));
 		modulesProvider.setSelectedModules(Set.of(modExe));
 		waitForSwing();
 		assertTrue(modulesProvider.actionSelectAddresses.isEnabled());
@@ -608,6 +613,8 @@ public class DebuggerModulesProviderTest extends AbstractGhidraHeadedDebuggerGUI
 		try (UndoableTransaction tid = tb.startTransaction()) {
 			modExe.setName("/bin/echo"); // File has to exist
 		}
+		waitForPass(() -> assertEquals(2, modulesProvider.moduleTable.getRowCount()));
+
 		modulesProvider.setSelectedModules(Set.of(modExe));
 		waitForSwing();
 		performAction(modulesProvider.actionImportFromFileSystem, false);
@@ -616,6 +623,10 @@ public class DebuggerModulesProviderTest extends AbstractGhidraHeadedDebuggerGUI
 		dialog.close();
 	}
 
+	protected Set<SectionRow> visibleSections() {
+		return Set.copyOf(modulesProvider.sectionFilterPanel.getTableFilterModel().getModelData());
+	}
+
 	@Test
 	public void testActionFilterSections() throws Exception {
 		addPlugin(tool, ImporterPlugin.class);
@@ -623,35 +634,29 @@ public class DebuggerModulesProviderTest extends AbstractGhidraHeadedDebuggerGUI
 		addModules();
 		traceManager.activateTrace(tb.trace);
 		waitForSwing();
+		waitForPass(() -> assertEquals(2, modulesProvider.moduleTable.getRowCount()));
+		waitForPass(() -> assertEquals(4, modulesProvider.sectionTable.getRowCount()));
 
-		Set<SectionRow> visible =
-			Set.copyOf(modulesProvider.sectionFilterPanel.getTableFilterModel().getModelData());
-		assertEquals(4, visible.size());
+		assertEquals(4, visibleSections().size());
 
 		modulesProvider.setSelectedModules(Set.of(modExe));
 		waitForSwing();
 
-		visible =
-			Set.copyOf(modulesProvider.sectionFilterPanel.getTableFilterModel().getModelData());
-		assertEquals(4, visible.size());
+		assertEquals(4, visibleSections().size());
 
 		assertTrue(modulesProvider.actionFilterSectionsByModules.isEnabled());
 		performAction(modulesProvider.actionFilterSectionsByModules);
 		waitForSwing();
 
-		visible =
-			Set.copyOf(modulesProvider.sectionFilterPanel.getTableFilterModel().getModelData());
-		assertEquals(2, visible.size());
-		for (SectionRow row : visible) {
+		assertEquals(2, visibleSections().size());
+		for (SectionRow row : visibleSections()) {
 			assertEquals(modExe, row.getModule());
 		}
 
 		modulesProvider.setSelectedModules(Set.of());
 		waitForSwing();
 
-		visible =
-			Set.copyOf(modulesProvider.sectionFilterPanel.getTableFilterModel().getModelData());
-		assertEquals(4, visible.size());
+		waitForPass(() -> assertEquals(4, visibleSections().size()));
 	}
 
 	protected static final Set<String> POPUP_ACTIONS = Set.of(
@@ -693,6 +698,7 @@ public class DebuggerModulesProviderTest extends AbstractGhidraHeadedDebuggerGUI
 		addModules();
 		traceManager.activateTrace(tb.trace);
 		waitForSwing();
+		waitForPass(() -> assertEquals(4, modulesProvider.sectionTable.getRowCount()));
 
 		clickTableCellWithButton(modulesProvider.sectionTable, 0, 0, MouseEvent.BUTTON3);
 		waitForSwing();

Ghidra/Debug/Debugger/src/test/java/ghidra/app/plugin/core/debug/gui/modules/DebuggerStaticMappingProviderTest.java

@@ -171,9 +171,10 @@ public class DebuggerStaticMappingProviderTest extends AbstractGhidraHeadedDebug
 		waitForDomainObject(tb.trace);
 
 		// First check that all records are displayed
-		List<StaticMappingRow> correlationsDisplayed =
+		waitForPass(() -> assertEquals(3, mappingsProvider.mappingTable.getRowCount()));
+		List<StaticMappingRow> mappingsDisplayed =
 			mappingsProvider.mappingTableModel.getModelData();
-		assertEquals(3, correlationsDisplayed.size());
+		assertEquals(3, mappingsDisplayed.size());
 
 		// Select and remove the first 2 via the action
 		// NOTE: I'm not responsible for making the transaction here. The UI should do it.
@@ -182,9 +183,9 @@ public class DebuggerStaticMappingProviderTest extends AbstractGhidraHeadedDebug
 		waitForDomainObject(tb.trace);
 
 		// Now, check that only the final one remains
-		correlationsDisplayed = mappingsProvider.mappingTableModel.getModelData();
-		assertEquals(1, correlationsDisplayed.size());
-		StaticMappingRow record = correlationsDisplayed.get(0);
+		mappingsDisplayed = mappingsProvider.mappingTableModel.getModelData();
+		assertEquals(1, mappingsDisplayed.size());
+		StaticMappingRow record = mappingsDisplayed.get(0);
 		assertEquals(tb.addr(0xdeadbeef + 0x180), record.getTraceAddress());
 
 		// Check that they were removed from the trace as well

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/database/DBTrace.java

@@ -525,19 +525,23 @@ public class DBTrace extends DBCachedDomainObjectAdapter implements Trace, Trace
 
 	@Override
 	public DBTraceProgramView getFixedProgramView(long snap) {
-		DBTraceProgramView view = fixedProgramViews.computeIfAbsent(snap, t -> {
-			Msg.debug(this, "Creating fixed view at snap=" + snap);
-			return new DBTraceProgramView(this, snap, baseCompilerSpec);
-		});
-		return view;
+		synchronized (fixedProgramViews) {
+			DBTraceProgramView view = fixedProgramViews.computeIfAbsent(snap, t -> {
+				Msg.debug(this, "Creating fixed view at snap=" + snap);
+				return new DBTraceProgramView(this, snap, baseCompilerSpec);
+			});
+			return view;
+		}
 	}
 
 	@Override
 	public DBTraceVariableSnapProgramView createProgramView(long snap) {
-		DBTraceVariableSnapProgramView view =
-			new DBTraceVariableSnapProgramView(this, snap, baseCompilerSpec);
-		programViews.put(view, null);
-		return view;
+		synchronized (programViews) {
+			DBTraceVariableSnapProgramView view =
+				new DBTraceVariableSnapProgramView(this, snap, baseCompilerSpec);
+			programViews.put(view, null);
+			return view;
+		}
 	}
 
 	@Override
@@ -675,10 +679,14 @@ public class DBTrace extends DBCachedDomainObjectAdapter implements Trace, Trace
 	}
 
 	protected void allViews(Consumer<DBTraceProgramView> action) {
-		for (DBTraceProgramView view : programViews.keySet()) {
-			action.accept(view);
+		Collection<DBTraceProgramView> all = new ArrayList<>();
+		synchronized (programViews) {
+			all.addAll(programViews.keySet());
 		}
-		for (DBTraceProgramView view : fixedProgramViews.values()) {
+		synchronized (fixedProgramViews) {
+			all.addAll(fixedProgramViews.values());
+		}
+		for (DBTraceProgramView view : all) {
 			action.accept(view);
 		}
 	}

Ghidra/Debug/Framework-TraceModeling/src/main/java/ghidra/trace/util/DefaultTraceTimeViewport.java

@@ -56,30 +56,20 @@ public class DefaultTraceTimeViewport implements TraceTimeViewport {
 		}
 
 		private void snapshotAdded(TraceSnapshot snapshot) {
-			if (snapshot.getSchedule() == null) {
-				return;
-			}
-			if (spanSet.contains(snapshot.getKey())) {
-				recomputeSnapRanges();
-				return;
+			if (checkSnapshotAddedNeedsRefresh(snapshot)) {
+				refreshSnapRanges();
 			}
 		}
 
 		private void snapshotChanged(TraceSnapshot snapshot) {
-			if (isLower(snapshot.getKey())) {
-				recomputeSnapRanges();
-				return;
-			}
-			if (spanSet.contains(snapshot.getKey()) && snapshot.getSchedule() != null) {
-				recomputeSnapRanges();
-				return;
+			if (checkSnapshotChangedNeedsRefresh(snapshot)) {
+				refreshSnapRanges();
 			}
 		}
 
 		private void snapshotDeleted(TraceSnapshot snapshot) {
-			if (isLower(snapshot.getKey())) {
-				recomputeSnapRanges();
-				return;
+			if (checkSnapshotDeletedNeedsRefresh(snapshot)) {
+				refreshSnapRanges();
 			}
 		}
 
@@ -117,27 +107,31 @@ public class DefaultTraceTimeViewport implements TraceTimeViewport {
 
 	@Override
 	public boolean containsAnyUpper(Range<Long> range) {
-		// NB. This should only ever visit the first range intersecting that given
-		for (Range<Long> intersecting : spanSet.subRangeSet(range).asRanges()) {
-			if (range.contains(intersecting.upperEndpoint())) {
-				return true;
+		synchronized (ordered) {
+			// NB. This should only ever visit the first range intersecting that given
+			for (Range<Long> intersecting : spanSet.subRangeSet(range).asRanges()) {
+				if (range.contains(intersecting.upperEndpoint())) {
+					return true;
+				}
 			}
+			return false;
 		}
-		return false;
 	}
 
 	@Override
 	public <T> boolean isCompletelyVisible(AddressRange range, Range<Long> lifespan, T object,
 			Occlusion<T> occlusion) {
-		for (Range<Long> rng : ordered) {
-			if (lifespan.contains(rng.upperEndpoint())) {
-				return true;
-			}
-			if (occlusion.occluded(object, range, rng)) {
-				return false;
+		synchronized (ordered) {
+			for (Range<Long> rng : ordered) {
+				if (lifespan.contains(rng.upperEndpoint())) {
+					return true;
+				}
+				if (occlusion.occluded(object, range, rng)) {
+					return false;
+				}
 			}
+			return false;
 		}
-		return false;
 	}
 
 	@Override
@@ -147,13 +141,15 @@ public class DefaultTraceTimeViewport implements TraceTimeViewport {
 			return new AddressSet();
 		}
 		AddressSet remains = new AddressSet(set);
-		for (Range<Long> rng : ordered) {
-			if (lifespan.contains(rng.upperEndpoint())) {
-				return remains;
-			}
-			occlusion.remove(object, remains, rng);
-			if (remains.isEmpty()) {
-				return remains;
+		synchronized (ordered) {
+			for (Range<Long> rng : ordered) {
+				if (lifespan.contains(rng.upperEndpoint())) {
+					return remains;
+				}
+				occlusion.remove(object, remains, rng);
+				if (remains.isEmpty()) {
+					return remains;
+				}
 			}
 		}
 		// This condition should have been detected by !containsAnyUpper
@@ -161,14 +157,17 @@ public class DefaultTraceTimeViewport implements TraceTimeViewport {
 	}
 
 	protected boolean isLower(long lower) {
-		Range<Long> range = spanSet.rangeContaining(lower);
-		if (range == null) {
-			return false;
+		synchronized (ordered) {
+			Range<Long> range = spanSet.rangeContaining(lower);
+			if (range == null) {
+				return false;
+			}
+			return range.lowerEndpoint().longValue() == lower;
 		}
-		return range.lowerEndpoint().longValue() == lower;
 	}
 
-	protected boolean addSnapRange(long lower, long upper) {
+	protected static boolean addSnapRange(long lower, long upper, RangeSet<Long> spanSet,
+			List<Range<Long>> ordered) {
 		if (spanSet.contains(lower)) {
 			return false;
 		}
@@ -178,7 +177,7 @@ public class DefaultTraceTimeViewport implements TraceTimeViewport {
 		return true;
 	}
 
-	protected TraceSnapshot locateMostRecentFork(long from) {
+	protected static TraceSnapshot locateMostRecentFork(TraceTimeManager timeManager, long from) {
 		while (true) {
 			TraceSnapshot prev = timeManager.getMostRecentSnapshot(from);
 			if (prev == null) {
@@ -203,11 +202,23 @@ public class DefaultTraceTimeViewport implements TraceTimeViewport {
 		}
 	}
 
-	protected void traverseAndAddForkRanges(long curSnap) {
+	/**
+	 * Construct the ranges (set and ordered)
+	 * 
+	 * <p>
+	 * NOTE: I cannot hold the lock during this, because I also require the DB's read lock. There
+	 * are other operations, e.g., addRegion, that will hold the DB's write lock, and then also
+	 * require the viewport's lock to check if it is visible. That would cause the classic tango of
+	 * death.
+	 * 
+	 * @param curSnap the seed snap
+	 */
+	protected static void collectForkRanges(TraceTimeManager timeManager, long curSnap,
+			RangeSet<Long> spanSet, List<Range<Long>> ordered) {
 		while (true) {
-			TraceSnapshot fork = locateMostRecentFork(curSnap);
+			TraceSnapshot fork = locateMostRecentFork(timeManager, curSnap);
 			long prevSnap = fork == null ? Long.MIN_VALUE : fork.getKey();
-			if (!addSnapRange(prevSnap, curSnap)) {
+			if (!addSnapRange(prevSnap, curSnap, spanSet, ordered)) {
 				return;
 			}
 			if (fork == null) {
@@ -217,71 +228,124 @@ public class DefaultTraceTimeViewport implements TraceTimeViewport {
 		}
 	}
 
-	protected void recomputeSnapRanges() {
-		spanSet.clear();
-		ordered.clear();
-		traverseAndAddForkRanges(snap);
+	protected void refreshSnapRanges() {
+		RangeSet<Long> spanSet = TreeRangeSet.create();
+		List<Range<Long>> ordered = new ArrayList<>();
+		collectForkRanges(timeManager, snap, spanSet, ordered);
+		synchronized (this.ordered) {
+			this.spanSet.clear();
+			this.ordered.clear();
+			this.spanSet.addAll(spanSet);
+			this.ordered.addAll(ordered);
+		}
 		assert !ordered.isEmpty();
 		changeListeners.fire.run();
 	}
 
 	public void setSnap(long snap) {
 		this.snap = snap;
-		recomputeSnapRanges();
+		refreshSnapRanges();
+	}
+
+	protected boolean checkSnapshotAddedNeedsRefresh(TraceSnapshot snapshot) {
+		synchronized (ordered) {
+			if (snapshot.getSchedule() == null) {
+				return false;
+			}
+			if (spanSet.contains(snapshot.getKey())) {
+				return true;
+			}
+			return false;
+		}
+	}
+
+	protected boolean checkSnapshotChangedNeedsRefresh(TraceSnapshot snapshot) {
+		synchronized (ordered) {
+			if (isLower(snapshot.getKey())) {
+				return true;
+			}
+			if (spanSet.contains(snapshot.getKey()) && snapshot.getSchedule() != null) {
+				return true;
+			}
+			return false;
+		}
+	}
+
+	protected boolean checkSnapshotDeletedNeedsRefresh(TraceSnapshot snapshot) {
+		synchronized (ordered) {
+			if (isLower(snapshot.getKey())) {
+				return true;
+			}
+			return false;
+		}
 	}
 
 	@Override
 	public boolean isForked() {
-		return ordered.size() > 1;
+		synchronized (ordered) {
+			return ordered.size() > 1;
+		}
 	}
 
 	@Override
 	public List<Long> getOrderedSnaps() {
-		return ordered
-				.stream()
-				.map(Range::upperEndpoint)
-				.collect(Collectors.toList());
+		synchronized (ordered) {
+			return ordered
+					.stream()
+					.map(Range::upperEndpoint)
+					.collect(Collectors.toList());
+		}
 	}
 
 	@Override
 	public List<Long> getReversedSnaps() {
-		return Lists.reverse(ordered)
-				.stream()
-				.map(Range::upperEndpoint)
-				.collect(Collectors.toList());
+		synchronized (ordered) {
+			return Lists.reverse(ordered)
+					.stream()
+					.map(Range::upperEndpoint)
+					.collect(Collectors.toList());
+		}
 	}
 
 	@Override
 	public <T> T getTop(Function<Long, T> func) {
-		for (Range<Long> rng : ordered) {
-			T t = func.apply(rng.upperEndpoint());
-			if (t != null) {
-				return t;
+		synchronized (ordered) {
+			for (Range<Long> rng : ordered) {
+				T t = func.apply(rng.upperEndpoint());
+				if (t != null) {
+					return t;
+				}
 			}
+			return null;
 		}
-		return null;
 	}
 
 	@Override
 	public <T> Iterator<T> mergedIterator(Function<Long, Iterator<T>> iterFunc,
 			Comparator<? super T> comparator) {
-		if (!isForked()) {
-			return iterFunc.apply(snap);
+		List<Iterator<T>> iters;
+		synchronized (ordered) {
+			if (!isForked()) {
+				return iterFunc.apply(snap);
+			}
+			iters = ordered.stream()
+					.map(rng -> iterFunc.apply(rng.upperEndpoint()))
+					.collect(Collectors.toList());
 		}
-		List<Iterator<T>> iters = ordered.stream()
-				.map(rng -> iterFunc.apply(rng.upperEndpoint()))
-				.collect(Collectors.toList());
 		return new UniqIterator<>(new MergeSortingIterator<>(iters, comparator));
 	}
 
 	@Override
 	public AddressSetView unionedAddresses(Function<Long, AddressSetView> viewFunc) {
-		if (!isForked()) {
-			return viewFunc.apply(snap);
+		List<AddressSetView> views;
+		synchronized (ordered) {
+			if (!isForked()) {
+				return viewFunc.apply(snap);
+			}
+			views = ordered.stream()
+					.map(rng -> viewFunc.apply(rng.upperEndpoint()))
+					.collect(Collectors.toList());
 		}
-		List<AddressSetView> views = ordered.stream()
-				.map(rng -> viewFunc.apply(rng.upperEndpoint()))
-				.collect(Collectors.toList());
 		return new UnionAddressSetView(views);
 	}
 }