Merge remote-tracking branch 'origin/GP-2371-dragonmacher-tool-restore-exception--SQUASHED' into patch

Ghidra/Framework/Docking/src/main/java/docking/ComponentPlaceholder.java

@@ -35,6 +35,12 @@ import utilities.util.reflection.ReflectionUtilities;
  * Class to hold information about a dockable component with respect to its position within the
  * windowing system.  It also holds identification information about the provider so that its
  * location can be reused when the provider is re-opened.
+ * <p>
+ * The placeholder will be used to link previously saved position information.  The tool will
+ * initially construct plugins and their component providers with default position information.
+ * Then, any existing xml data will be restored, which may have provider position information.
+ * The restoring of the xml will create placeholders with this saved information.  Finally, the
+ * restored placeholders will be linked with existing component providers.
  */
 public class ComponentPlaceholder {
 	private String name;

Ghidra/Framework/Docking/src/main/java/docking/DetachedWindowNode.java

@@ -474,6 +474,16 @@ class DetachedWindowNode extends WindowNode {
 	@Override
 	void dispose() {
 
+		disposeWindow();
+
+		if (child != null) {
+			child.parent = null;
+			child.dispose();
+			child = null;
+		}
+	}
+
+	private void disposeWindow() {
 		if (dropTargetHandler != null) {
 			dropTargetHandler.dispose();
 		}
@@ -485,12 +495,24 @@ class DetachedWindowNode extends WindowNode {
 			window.dispose();
 			window = null;
 		}
+	}
 
+	/**
+	 * An oddly named method for an odd use case.  This method is meant to take an existing window,
+	 * such as that created by default when loading plugins, and hide it.   Clients cannot simply
+	 * call dispose(), as that would also dispose the entire child hierarchy of this class.  This
+	 * method is intended to keep all children not disposed while allowing this window node to go
+	 * away.
+	 */
+	void disconnect() {
+
+		// note: do not call child.dispose() here
 		if (child != null) {
 			child.parent = null;
-			child.dispose();
 			child = null;
 		}
+
+		disposeWindow();
 	}
 
 	@Override

Ghidra/Framework/Docking/src/main/java/docking/PlaceholderManager.java

@@ -43,17 +43,22 @@ class PlaceholderManager {
 	}
 
 	ComponentPlaceholder replacePlaceholder(ComponentProvider provider,
-			ComponentPlaceholder oldPlaceholder) {
+			ComponentPlaceholder defaultPlaceholder) {
 
-		ComponentPlaceholder newPlaceholder = createOrRecyclePlaceholder(provider, oldPlaceholder);
+		// Note: the 'restoredPlaceholder' is from xml; the 'defaultPlaceholder' is that which was
+		// created by a plugin as it was constructed.  If there is no placeholder in the xml,
+		// then the original 'defaultPlaceholder' will be returned from
+		// createOrRecyclePlaceholder().
+		ComponentPlaceholder restoredPlaceholder =
+			createOrRecyclePlaceholder(provider, defaultPlaceholder);
 
-		moveActions(oldPlaceholder, newPlaceholder);
-		if (!oldPlaceholder.isHeaderShowing()) {
-			newPlaceholder.showHeader(false);
+		moveActions(defaultPlaceholder, restoredPlaceholder);
+		if (!defaultPlaceholder.isHeaderShowing()) {
+			restoredPlaceholder.showHeader(false);
 		}
 
-		if (oldPlaceholder.isShowing() != newPlaceholder.isShowing()) {
-			if (newPlaceholder.isShowing()) {
+		if (defaultPlaceholder.isShowing() != restoredPlaceholder.isShowing()) {
+			if (restoredPlaceholder.isShowing()) {
 				provider.componentShown();
 			}
 			else {
@@ -61,11 +66,13 @@ class PlaceholderManager {
 			}
 		}
 
-		if (newPlaceholder != oldPlaceholder) {
-			oldPlaceholder.dispose();
-			removePlaceholder(oldPlaceholder);
+		// if we have found a replacement placeholder, then remove the default placeholder
+		if (restoredPlaceholder != defaultPlaceholder) {
+			defaultPlaceholder.dispose();
+			removePlaceholder(defaultPlaceholder);
 		}
-		return newPlaceholder;
+
+		return restoredPlaceholder;
 	}
 
 	/**

Ghidra/Framework/Docking/src/main/java/docking/RootNode.java

@@ -445,7 +445,13 @@ class RootNode extends WindowNode {
 
 	/**
 	 * Restores the component hierarchy from the given XML JDOM element.
-	 * @param root the XML from which to restore the state.
+	 * <p>
+	 * The process of restoring from xml will create new {@link ComponentPlaceholder}s that will be
+	 * used to replace any existing matching placeholders.  This allows the already loaded default
+	 * placeholders to be replaced by the previously saved configuration.
+	 * 
+	 * @param rootNodeElement the XML from which to restore the state.
+	 * @return the newly created placeholders
 	 */
 	List<ComponentPlaceholder> restoreFromXML(Element rootNodeElement) {
 		invalid = true;
@@ -455,7 +461,7 @@ class RootNode extends WindowNode {
 		detachedWindows.clear();
 		for (DetachedWindowNode windowNode : copy) {
 			notifyWindowRemoved(windowNode);
-			windowNode.dispose();
+			windowNode.disconnect();
 		}
 
 		int x = Integer.parseInt(rootNodeElement.getAttributeValue("X_POS"));