fix(gui): save current caret position and add it to tab code jump event (#2409)

Author: skylot

jadx-gui/src/main/java/jadx/gui/ui/codearea/AbstractCodeArea.java

@@ -429,8 +429,12 @@ private void highlightAllMatches(@Nullable String str) {
 		SearchEngine.markAll(this, context);
 	}
 
-	public JumpPosition getCurrentPosition() {
-		return new JumpPosition(node, getCaretPosition());
+	public @Nullable JumpPosition getCurrentPosition() {
+		int pos = getCaretPosition();
+		if (pos == 0) {
+			return null;
+		}
+		return new JumpPosition(node, pos);
 	}
 
 	public int getLineStartFor(int pos) throws BadLocationException {

jadx-gui/src/main/java/jadx/gui/ui/tab/ITabStatesListener.java

@@ -2,18 +2,35 @@
 
 import java.util.List;
 
+import org.jetbrains.annotations.Nullable;
+
 import jadx.gui.ui.codearea.EditorViewState;
 import jadx.gui.utils.JumpPosition;
 
+/**
+ * Tabbed pane events listener
+ */
 public interface ITabStatesListener {
 
+	/**
+	 * Tab added to tabbed pane without become active (selected)
+	 */
 	default void onTabOpen(TabBlueprint blueprint) {
 	}
 
+	/**
+	 * Tab become active (selected)
+	 */
 	default void onTabSelect(TabBlueprint blueprint) {
 	}
 
-	default void onTabCodeJump(TabBlueprint blueprint, JumpPosition position) {
+	/**
+	 * Caret position changes.
+	 *
+	 * @param prevPos previous caret position; can be null if unknown; can be from another tab
+	 * @param newPos  new caret position, node refer to jump target node
+	 */
+	default void onTabCodeJump(TabBlueprint blueprint, @Nullable JumpPosition prevPos, JumpPosition newPos) {
 	}
 
 	default void onTabSmaliJump(TabBlueprint blueprint, int pos, boolean debugMode) {

jadx-gui/src/main/java/jadx/gui/ui/tab/LogTabStates.java

@@ -2,6 +2,7 @@
 
 import java.util.List;
 
+import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -25,8 +26,8 @@ public void onTabClose(TabBlueprint blueprint) {
 	}
 
 	@Override
-	public void onTabCodeJump(TabBlueprint blueprint, JumpPosition position) {
-		LOG.debug("onTabCodeJump: blueprint={}, position={}", blueprint, position);
+	public void onTabCodeJump(TabBlueprint blueprint, @Nullable JumpPosition prevPos, JumpPosition newPos) {
+		LOG.debug("onTabCodeJump: blueprint={}, prevPos={}, newPos={}", blueprint, prevPos, newPos);
 	}
 
 	@Override

jadx-gui/src/main/java/jadx/gui/ui/tab/NavigationController.java

@@ -20,16 +20,10 @@ public NavigationController(MainWindow mainWindow) {
 	}
 
 	public void navBack() {
-		if (jumps.size() > 1) {
-			jumps.updateCurPosition(mainWindow.getTabbedPane().getCurrentPosition());
-		}
 		jump(jumps.getPrev());
 	}
 
 	public void navForward() {
-		if (jumps.size() > 1) {
-			jumps.updateCurPosition(mainWindow.getTabbedPane().getCurrentPosition());
-		}
 		jump(jumps.getNext());
 	}
 
@@ -40,28 +34,20 @@ private void jump(@Nullable JumpPosition pos) {
 	}
 
 	@Override
-	public void onTabCodeJump(TabBlueprint blueprint, JumpPosition position) {
-		if (position.equals(jumps.getCurrent())) {
+	public void onTabCodeJump(TabBlueprint blueprint, @Nullable JumpPosition prevPos, JumpPosition newPos) {
+		if (newPos.equals(jumps.getCurrent())) {
 			// ignore self-initiated jumps
 			return;
 		}
-		saveCurrentPosition();
-		jumps.addPosition(position);
+		jumps.addPosition(prevPos);
+		jumps.addPosition(newPos);
 	}
 
 	@Override
 	public void onTabSmaliJump(TabBlueprint blueprint, int pos, boolean debugMode) {
-		saveCurrentPosition();
 		// TODO: save smali jump
 	}
 
-	private void saveCurrentPosition() {
-		JumpPosition curPos = mainWindow.getTabbedPane().getCurrentPosition();
-		if (curPos != null) {
-			jumps.addPosition(curPos);
-		}
-	}
-
 	public void reset() {
 		jumps.reset();
 	}

jadx-gui/src/main/java/jadx/gui/ui/tab/TabbedPane.java

@@ -211,8 +211,8 @@ public TabsController getTabsController() {
 	private @Nullable ContentPanel showCode(JumpPosition jumpPos) {
 		ContentPanel contentPanel = getContentPanel(jumpPos.getNode());
 		if (contentPanel != null) {
-			scrollToPos(contentPanel, jumpPos.getPos());
 			selectTab(contentPanel);
+			scrollToPos(contentPanel, jumpPos.getPos());
 		}
 		return contentPanel;
 	}
@@ -224,8 +224,8 @@ private void scrollToPos(ContentPanel contentPanel, int pos) {
 		}
 		if (contentPanel instanceof AbstractCodeContentPanel) {
 			AbstractCodeArea codeArea = ((AbstractCodeContentPanel) contentPanel).getCodeArea();
-			codeArea.scrollToPos(pos);
 			codeArea.requestFocus();
+			codeArea.scrollToPos(pos);
 		}
 	}
 
@@ -414,7 +414,7 @@ public void onTabSelect(TabBlueprint blueprint) {
 	}
 
 	@Override
-	public void onTabCodeJump(TabBlueprint blueprint, JumpPosition position) {
+	public void onTabCodeJump(TabBlueprint blueprint, @Nullable JumpPosition prevPos, JumpPosition position) {
 		showCode(position);
 	}
 

jadx-gui/src/main/java/jadx/gui/ui/tab/TabsController.java

@@ -37,6 +37,7 @@ public class TabsController {
 
 	public TabsController(MainWindow mainWindow) {
 		this.mainWindow = mainWindow;
+		// addListener(new LogTabStates());
 	}
 
 	public MainWindow getMainWindow() {
@@ -76,6 +77,10 @@ public TabBlueprint openTab(JNode node, boolean hidden) {
 	}
 
 	public void selectTab(JNode node) {
+		if (selectedTab != null && selectedTab.getNode() == node) {
+			// already selected
+			return;
+		}
 		TabBlueprint blueprint = openTab(node);
 		selectedTab = blueprint;
 		listeners.forEach(l -> l.onTabSelect(blueprint));
@@ -141,10 +146,11 @@ private void jumpToInnerClass(JNode node, JavaClass codeParent, JClass jumpCls)
 	 * Prefer {@link TabsController#codeJump(JNode)} method
 	 */
 	public void codeJump(JumpPosition pos) {
+		JumpPosition currentPosition = mainWindow.getTabbedPane().getCurrentPosition();
 		if (selectedTab == null || selectedTab.getNode() != pos.getNode()) {
 			selectTab(pos.getNode());
 		}
-		listeners.forEach(l -> l.onTabCodeJump(selectedTab, pos));
+		listeners.forEach(l -> l.onTabCodeJump(selectedTab, currentPosition, pos));
 	}
 
 	public void smaliJump(JClass cls, int pos, boolean debugMode) {

jadx-gui/src/main/java/jadx/gui/utils/JumpManager.java

@@ -6,31 +6,40 @@
 import org.jetbrains.annotations.Nullable;
 
 public class JumpManager {
+	/**
+	 * Maximum number of elements to store in a jump list
+	 */
+	private static final int MAX_JUMPS = 100;
 
-	private final List<JumpPosition> list = new ArrayList<>();
+	/**
+	 * This number of elements will be removed from the start if a list becomes bigger than MAX_JUMPS.
+	 * List grow most of the time, so removing should be done in big batches to not run very often.
+	 * Because of this, an effective jump history size will vary
+	 * from (MAX_JUMPS - LIST_SHRINK_COUNT) to MAX_JUMPS over time.
+	 */
+	private static final int LIST_SHRINK_COUNT = 50;
+
+	private final List<JumpPosition> list = new ArrayList<>(MAX_JUMPS);
 	private int currentPos = 0;
 
-	public void addPosition(JumpPosition pos) {
-		if (ignoreJump(pos)) {
+	public void addPosition(@Nullable JumpPosition pos) {
+		if (pos == null || ignoreJump(pos)) {
 			return;
 		}
 		currentPos++;
 		if (currentPos >= list.size()) {
 			list.add(pos);
+			if (list.size() >= MAX_JUMPS) {
+				list.subList(0, LIST_SHRINK_COUNT).clear();
+			}
 			currentPos = list.size() - 1;
 		} else {
+			// discard forward history after navigating back and jumping to a new place
 			list.set(currentPos, pos);
-			int size = list.size();
-			for (int i = currentPos + 1; i < size; i++) {
-				list.set(i, null);
-			}
+			list.subList(currentPos + 1, list.size()).clear();
 		}
 	}
 
-	public void updateCurPosition(JumpPosition pos) {
-		list.set(currentPos, pos);
-	}
-
 	public int size() {
 		return list.size();
 	}

jadx-gui/src/main/java/jadx/gui/utils/JumpPosition.java

@@ -47,6 +47,6 @@ public int hashCode() {
 
 	@Override
 	public String toString() {
-		return "Jump: " + node + " : " + pos;
+		return "Jump{" + node + ":" + pos + '}';
 	}
 }