Windows: Wrap window pointers to enforce correct checking of NULL pointers

core/src/test/java/com/github/weisj/darklaf/core/test/PointerUtilTest.java

@@ -1,7 +1,7 @@
 /*
  * MIT License
  *
- * Copyright (c) 2019-2021 Jannis Weis
+ * Copyright (c) 2019-2022 Jannis Weis
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
  * associated documentation files (the "Software"), to deal in the Software without restriction,
@@ -46,7 +46,7 @@ class PointerUtilTest {
             Window frame = new JWindow();
             frame.setAutoRequestFocus(false);
             SwingUtilities.invokeAndWait(() -> frame.setVisible(true));
-            Assertions.assertEquals(Native.getWindowID(frame), PointerUtil.getHWND(frame));
+            Assertions.assertEquals(Native.getWindowID(frame), PointerUtil.getHWND(frame).value());
             SwingUtilities.invokeLater(() -> {
                 frame.setVisible(false);
                 frame.dispose();

windows/src/main/java/com/github/weisj/darklaf/platform/windows/PointerUtil.java

@@ -21,6 +21,7 @@
 package com.github.weisj.darklaf.platform.windows;
 
 import java.awt.*;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import javax.swing.*;
@@ -32,23 +33,45 @@ public final class PointerUtil {
 
     private static final Logger LOGGER = LogUtil.getLogger(PointerUtil.class);
 
+    public static class WindowPointer {
+        private final long hwnd;
+
+        public WindowPointer(final long hwnd) {
+            this.hwnd = hwnd;
+        }
+
+        public boolean isValid() {
+            return hwnd != 0;
+        }
+
+        public long value() {
+            return hwnd;
+        }
+
+        @Override
+        public String toString() {
+            return String.valueOf(hwnd);
+        }
+    }
+
     /**
      * Get the window handle for the window the given component descends from.
      *
      * @param component the component.
      * @return the handle.
      */
-    public static long getHWND(final Component component) {
+    public static WindowPointer getHWND(final Component component) {
         Window window = component instanceof Window
                 ? (Window) component
                 : SwingUtilities.getWindowAncestor(component);
         String javaLibPath = SystemInfo.JAVA_HOME != null
                 ? SystemInfo.JAVA_HOME + "/bin/jawt.dll"
                 : "jawt.dll";
-        long hwnd = JNIDecorationsWindows.getWindowHWND(window, javaLibPath);
-        if (hwnd < 0) {
-            LOGGER.severe("Couldn't get HWND of window (errorCode =" + hwnd + ")." + component);
+        try {
+            return new WindowPointer(JNIDecorationsWindows.getWindowHWND(window, javaLibPath));
+        } catch (Exception e) {
+            LOGGER.log(Level.SEVERE, "Couldn't get HWND of window " + component, e);
+            return new WindowPointer(0);
         }
-        return hwnd;
     }
 }

windows/src/main/java/com/github/weisj/darklaf/platform/windows/WindowsDecorationsProvider.java

@@ -59,14 +59,14 @@ public class WindowsDecorationsProvider implements DecorationsProvider {
         if (!window.isDisplayable()) {
             window.addNotify();
         }
-        long hwnd = PointerUtil.getHWND(window);
-        if (hwnd > 0) {
-            JNIDecorationsWindows.installPopupMenuDecorations(hwnd);
+        PointerUtil.WindowPointer hwnd = PointerUtil.getHWND(window);
+        if (hwnd.isValid()) {
+            JNIDecorationsWindows.installPopupMenuDecorations(hwnd.value());
             if (window instanceof RootPaneContainer) {
                 JRootPane rootPane = ((RootPaneContainer) window).getRootPane();
                 Color bg = rootPane != null ? rootPane.getBackground() : null;
                 if (bg != null) {
-                    JNIDecorationsWindows.setBackground(hwnd, bg.getRed(), bg.getGreen(), bg.getBlue());
+                    JNIDecorationsWindows.setBackground(hwnd.value(), bg.getRed(), bg.getGreen(), bg.getBlue());
                 }
             }
         }
@@ -75,9 +75,9 @@ public class WindowsDecorationsProvider implements DecorationsProvider {
     @Override
     public void uninstallPopupWindow(final Window window) {
         if (window.isDisplayable()) {
-            long hwnd = PointerUtil.getHWND(window);
-            if (hwnd != 0) {
-                JNIDecorationsWindows.uninstallDecorations(hwnd, false);
+            PointerUtil.WindowPointer hwnd = PointerUtil.getHWND(window);
+            if (hwnd.isValid()) {
+                JNIDecorationsWindows.uninstallDecorations(hwnd.value(), false);
             }
             window.dispose();
         }

windows/src/main/java/com/github/weisj/darklaf/platform/windows/ui/WindowsTitlePane.java

@@ -94,7 +94,7 @@ public class WindowsTitlePane extends CustomTitlePane {
     private Action minimizeAction;
     private JLabel titleLabel;
     private final Window window;
-    private long windowHandle;
+    private PointerUtil.WindowPointer windowHandle = new PointerUtil.WindowPointer(0);
     private int state;
 
     private Color inactiveBackground;
@@ -190,11 +190,11 @@ public class WindowsTitlePane extends CustomTitlePane {
     }
 
     protected void uninstallDecorations(final boolean removeDecorations) {
-        if (windowHandle != 0) {
+        if (windowHandle.isValid()) {
             if (removeDecorations) {
-                JNIDecorationsWindows.uninstallDecorations(windowHandle, decorationStyle != JRootPane.NONE);
+                JNIDecorationsWindows.uninstallDecorations(windowHandle.value(), decorationStyle != JRootPane.NONE);
             }
-            windowHandle = 0;
+            windowHandle = new PointerUtil.WindowPointer(0);
         }
     }
 
@@ -224,9 +224,9 @@ public class WindowsTitlePane extends CustomTitlePane {
     @Override
     public void setDecorationsStyle(final int style) {
         super.setDecorationsStyle(style);
-        if (style == JRootPane.NONE && windowHandle != 0) {
+        if (style == JRootPane.NONE && windowHandle.isValid()) {
             uninstall(true);
-        } else if (windowHandle == 0) {
+        } else if (!windowHandle.isValid()) {
             install();
         }
     }
@@ -236,14 +236,15 @@ public class WindowsTitlePane extends CustomTitlePane {
         if (!window.isDisplayable()) return false;
         if (window instanceof Dialog || window instanceof Frame) {
             windowHandle = PointerUtil.getHWND(window);
-            if (windowHandle > 0) {
+            if (windowHandle.isValid()) {
                 LOGGER.fine("Installing decorations for window " + windowHandle);
-                if (!JNIDecorationsWindows.installDecorations(windowHandle)) {
+                if (!JNIDecorationsWindows.installDecorations(windowHandle.value())) {
                     LOGGER.fine("Already installed.");
                 }
                 updateResizeBehaviour();
                 Color color = rootPane.getBackground();
-                JNIDecorationsWindows.setBackground(windowHandle, color.getRed(), color.getGreen(), color.getBlue());
+                JNIDecorationsWindows.setBackground(windowHandle.value(), color.getRed(), color.getGreen(),
+                        color.getBlue());
             } else {
                 uninstall(decorationStyle != JRootPane.NONE);
                 return false;
@@ -411,15 +412,15 @@ public class WindowsTitlePane extends CustomTitlePane {
     }
 
     private void minimize() {
-        JNIDecorationsWindows.minimize(windowHandle);
+        JNIDecorationsWindows.minimize(windowHandle.value());
     }
 
     private void maximize() {
-        JNIDecorationsWindows.maximize(windowHandle);
+        JNIDecorationsWindows.maximize(windowHandle.value());
     }
 
     private void restore() {
-        JNIDecorationsWindows.restore(windowHandle);
+        JNIDecorationsWindows.restore(windowHandle.value());
     }
 
     private void createActions() {
@@ -533,7 +534,7 @@ public class WindowsTitlePane extends CustomTitlePane {
         boolean res = isResizable();
         if (oldResizable != res) {
             oldResizable = res;
-            JNIDecorationsWindows.setResizable(windowHandle, res);
+            JNIDecorationsWindows.setResizable(windowHandle.value(), res);
         }
     }
 
@@ -769,7 +770,7 @@ public class WindowsTitlePane extends CustomTitlePane {
         // of the menubar.
         boolean emptyMenuBar = menuBarStealer.isMenuBarEmpty();
         boolean emptyContent = getDecorationStyle() == JRootPane.NONE && emptyMenuBar && title.length() == 0;
-        return windowHandle == 0
+        return !windowHandle.isValid()
                 || emptyContent
                 || (menuBarStealer.hasMenuBar() && !menuBarStealer.getMenuBar().isVisible());
     }
@@ -823,7 +824,7 @@ public class WindowsTitlePane extends CustomTitlePane {
     }
 
     protected void updateDragArea(final GraphicsConfiguration gc) {
-        JNIDecorationsWindows.updateValues(windowHandle,
+        JNIDecorationsWindows.updateValues(windowHandle.value(),
                 (int) Scale.scaleWidth(left, gc), (int) Scale.scaleWidth(right, gc),
                 (int) Scale.scaleHeight(height, gc), (int) Scale.scaleHeight(BUTTON_WIDTH, gc));
     }
@@ -945,7 +946,7 @@ public class WindowsTitlePane extends CustomTitlePane {
                     setState(frame.getExtendedState(), true);
                 }
                 if (KEY_RESIZABLE.equals(name)) {
-                    JNIDecorationsWindows.setResizable(windowHandle, Boolean.TRUE.equals(pce.getNewValue()));
+                    JNIDecorationsWindows.setResizable(windowHandle.value(), Boolean.TRUE.equals(pce.getNewValue()));
                     getRootPane().repaint();
                 }
             } else if (PropertyKey.TITLE.equals(name)) {
@@ -962,7 +963,8 @@ public class WindowsTitlePane extends CustomTitlePane {
             } else if (PropertyKey.BACKGROUND.equals(name) && pce.getNewValue() instanceof Color) {
                 Color color = (Color) pce.getNewValue();
                 if (color == null) return;
-                JNIDecorationsWindows.setBackground(windowHandle, color.getRed(), color.getGreen(), color.getBlue());
+                JNIDecorationsWindows.setBackground(windowHandle.value(), color.getRed(), color.getGreen(),
+                        color.getBlue());
             }
         }
     }