fixed bug where listing would jump when opening/closing large structures

or arrays

Ghidra/Framework/Docking/src/main/java/docking/widgets/fieldpanel/FieldPanel.java

@@ -961,23 +961,45 @@ public class FieldPanel extends JPanel
 
 	@Override
 	// BigLayoutModelListener
-	public void modelSizeChanged() {
-		BigInteger anchorIndex = layouts.isEmpty() ? BigInteger.ZERO : layouts.get(0).getIndex();
+	public void modelSizeChanged(IndexMapper indexMapper) {
+		BigInteger anchorIndex =
+			layouts.isEmpty() ? BigInteger.ZERO : indexMapper.map(layouts.get(0).getIndex());
 		int anchorOffset = layouts.isEmpty() ? 0 : layouts.get(0).getYPos();
 		Point cursorPoint = getCursorPoint();
-		AnchoredLayout layout = findLayoutOnScreen(cursorPosition.getIndex());
+		BigInteger cursorIndex = indexMapper.map(cursorPosition.getIndex());
+		AnchoredLayout layout = findLayoutOnScreen(cursorIndex);
 		if (layout != null) {
-			anchorIndex = cursorPosition.getIndex();
+			anchorIndex = cursorIndex;
 			anchorOffset = layout.getYPos();
 		}
 		notifyScrollListenerModelChanged();
 		layouts = layoutHandler.positionLayoutsAroundAnchor(anchorIndex, anchorOffset);
 
+		updateHighlight(indexMapper);
 		cursorHandler.updateCursor(cursorPoint);
 		notifyScrollListenerViewChangedAndRepaint();
 		invalidate();
 	}
 
+	private void updateHighlight(IndexMapper mapper) {
+		if (highlight.isEmpty()) {
+			return;
+		}
+		FieldSelection oldHighlight = highlight;
+		highlight = new FieldSelection();
+		for (FieldRange range : oldHighlight) {
+			FieldLocation start = range.getStart();
+			FieldLocation end = range.getEnd();
+			BigInteger startIndex = mapper.map(start.getIndex());
+			BigInteger endIndex = mapper.map(end.getIndex());
+			if (startIndex != null && endIndex != null) {
+				start.setIndex(startIndex);
+				end.setIndex(endIndex);
+				highlight.addRange(start, end);
+			}
+		}
+	}
+
 	@Override
 	protected void paintComponent(Graphics g) {
 		model.flushChanges();

Ghidra/Framework/Docking/src/main/java/docking/widgets/fieldpanel/internal/TestBigLayoutModel.java

@@ -24,6 +24,7 @@ import javax.swing.JFrame;
 
 import docking.widgets.fieldpanel.*;
 import docking.widgets.fieldpanel.field.*;
+import docking.widgets.fieldpanel.listener.IndexMapper;
 import docking.widgets.fieldpanel.listener.LayoutModelListener;
 import docking.widgets.fieldpanel.support.*;
 import docking.widgets.indexedscrollpane.IndexedScrollPane;
@@ -53,7 +54,7 @@ public class TestBigLayoutModel implements LayoutModel {
 	public void setNumIndexes(BigInteger n) {
 		this.numIndexes = n;
 		for (LayoutModelListener listener : listeners) {
-			listener.modelSizeChanged();
+			listener.modelSizeChanged(IndexMapper.IDENTITY_MAPPER);
 		}
 	}
 

Ghidra/Framework/Docking/src/main/java/docking/widgets/fieldpanel/listener/IdentityMapper.java

@@ -0,0 +1,30 @@
+/* ###
+ * IP: GHIDRA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package docking.widgets.fieldpanel.listener;
+
+import java.math.BigInteger;
+
+/**
+ * IndexMapper that always maps an index back to itself.
+ */
+class IdentityMapper implements IndexMapper {
+
+	@Override
+	public BigInteger map(BigInteger value) {
+		return value;
+	}
+
+}

Ghidra/Framework/Docking/src/main/java/docking/widgets/fieldpanel/listener/IndexMapper.java

@@ -0,0 +1,32 @@
+/* ###
+ * IP: GHIDRA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package docking.widgets.fieldpanel.listener;
+
+import java.math.BigInteger;
+
+import docking.widgets.fieldpanel.FieldPanel;
+
+/**
+ * Interface for mapping indexes when the LayoutModel changes. In other words, if the mapping
+ * of layout indexes to some data model changes and you want the {@link FieldPanel} to continue
+ * to display the same model data on the screen, the IndexMapper can be used to convert old
+ * indexes to new indexes.
+ */
+public interface IndexMapper {
+	public IndexMapper IDENTITY_MAPPER = new IdentityMapper();
+
+	public BigInteger map(BigInteger value);
+}

Ghidra/Framework/Docking/src/main/java/docking/widgets/fieldpanel/listener/LayoutModelListener.java

@@ -1,6 +1,5 @@
 /* ###
  * IP: GHIDRA
- * REVIEWED: YES
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,8 +21,10 @@ public interface LayoutModelListener {
 
 	/**
 	 * Called whenever the number of indexes changed
+	 * @param indexMapper Maps indexes from before the model size change to indexes after
+	 * the model size changed.
 	 */
-    void modelSizeChanged();
+	void modelSizeChanged(IndexMapper indexMapper);
 
 	/**
 	 * Called when the data at an index or range of indexes changes.