fix nested frameless windows & other minor tweaks

Signed-off-by: Yuhang Zhao <2546789017@qq.com>

include/FramelessHelper/Core/framelesshelpercore_global.h

@@ -56,10 +56,10 @@ QT_END_NAMESPACE
 #endif
 
 #if defined(Q_OS_WIN) && !defined(Q_OS_WINDOWS)
-#  define Q_OS_WINDOWS
+#  define Q_OS_WINDOWS // Since 5.14
 #endif
 
-#ifndef Q_DISABLE_COPY_MOVE
+#ifndef Q_DISABLE_COPY_MOVE // Since 5.13
 #  define Q_DISABLE_COPY_MOVE(Class) \
       Q_DISABLE_COPY(Class) \
       Class(Class &&) = delete; \
@@ -68,8 +68,6 @@ QT_END_NAMESPACE
 
 #if (QT_VERSION < QT_VERSION_CHECK(5, 10, 0))
    using QStringView = const QString &;
-#else
-#  include <QtCore/qstringview.h>
 #endif
 
 #if (QT_VERSION < QT_VERSION_CHECK(5, 14, 0))
@@ -77,6 +75,7 @@ QT_END_NAMESPACE
 #  define Q_NAMESPACE_EXPORT(...) Q_NAMESPACE
 #endif
 
+// MOC can't handle C++ attributes before 5.15.
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 15, 0))
 #  define Q_NODISCARD [[nodiscard]]
 #  define Q_MAYBE_UNUSED [[maybe_unused]]
@@ -108,7 +107,7 @@ QT_END_NAMESPACE
 #endif
 
 #if (QT_VERSION >= QT_VERSION_CHECK(6, 4, 0))
-  using namespace Qt::StringLiterals;
+  using namespace Qt::Literals::StringLiterals;
 #endif
 
 #ifndef FRAMELESSHELPER_BYTEARRAY_LITERAL
@@ -131,6 +130,14 @@ QT_END_NAMESPACE
 #  endif
 #endif
 
+#ifndef Q_UNREACHABLE_RETURN // Since 6.5
+#  define Q_UNREACHABLE_RETURN(...) \
+     do { \
+         Q_UNREACHABLE(); \
+         return __VA_ARGS__; \
+     } while (false)
+#endif
+
 #ifndef FRAMELESSHELPER_BYTEARRAY_CONSTANT2
 #  define FRAMELESSHELPER_BYTEARRAY_CONSTANT2(name, ba) \
      [[maybe_unused]] static const auto k##name = FRAMELESSHELPER_BYTEARRAY_LITERAL(ba);

src/core/framelesshelper_win.cpp

@@ -206,8 +206,7 @@ Q_GLOBAL_STATIC(Win32Helper, g_win32Helper)
         if (data.params.isInsideSystemButtons(qtScenePos, &buttonType)) {
             switch (buttonType) {
             case SystemButtonType::Unknown:
-                Q_ASSERT(false);
-                break;
+                Q_UNREACHABLE_RETURN(HTNOWHERE);
             case SystemButtonType::WindowIcon:
                 return HTSYSMENU;
             case SystemButtonType::Help:

src/core/framelesshelpercore_global.cpp

@@ -197,6 +197,10 @@ void initialize()
     Utils::fixupDialogsDpiScaling();
 #endif
 
+    // We need this flag to enable nested frameless windows, however,
+    // this flag is known to be __NOT__ compatible with QGLWidget.
+    QCoreApplication::setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
+
 #if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
     // Enable high DPI scaling by default, but only for Qt5 applications,
     // because this has become the default setting since Qt6 and it can't

src/core/utils_win.cpp

@@ -1681,8 +1681,7 @@ void Utils::setCornerStyleForWindow(const WId windowId, const WindowCornerStyle
         case WindowCornerStyle::Round:
             return _DWMWCP_ROUND;
         }
-        Q_ASSERT(false);
-        return _DWMWCP_DEFAULT;
+        Q_UNREACHABLE_RETURN(_DWMWCP_DEFAULT);
     }();
     const HRESULT hr = API_CALL_FUNCTION(DwmSetWindowAttribute,
         hwnd, _DWMWA_WINDOW_CORNER_PREFERENCE, &wcp, sizeof(wcp));
@@ -1739,8 +1738,7 @@ bool Utils::setBlurBehindWindowEnabled(const WId windowId, const BlurMode mode,
                 }
                 return BlurMode::Windows_Aero;
             }
-            Q_ASSERT(false); // Really should NOT go here.
-            return mode;
+            Q_UNREACHABLE_RETURN(BlurMode::Default);
         }();
         if (blurMode == BlurMode::Disable) {
             bool result = true;
@@ -1849,7 +1847,7 @@ bool Utils::setBlurBehindWindowEnabled(const WId windowId, const BlurMode mode,
                 } else if (blurMode == BlurMode::Windows_Aero) {
                     policy.State = ACCENT_ENABLE_BLURBEHIND;
                 } else {
-                    Q_ASSERT(false); // Really should NOT go here.
+                    Q_UNREACHABLE_RETURN(false);
                 }
                 WINDOWCOMPOSITIONATTRIBDATA wcad;
                 SecureZeroMemory(&wcad, sizeof(wcad));

src/quick/framelessquickhelper.cpp

@@ -275,8 +275,7 @@ void FramelessQuickHelperPrivate::setSystemButton(QQuickItem *item, const QuickG
     }
     switch (buttonType) {
     case QuickGlobal::SystemButtonType::Unknown:
-        Q_ASSERT(false);
-        break;
+        Q_UNREACHABLE_RETURN(static_cast<void>(0));
     case QuickGlobal::SystemButtonType::WindowIcon:
         data->windowIconButton = item;
         break;
@@ -800,8 +799,7 @@ void FramelessQuickHelperPrivate::setSystemButtonState(const QuickGlobal::System
     QQuickAbstractButton *quickButton = nullptr;
     switch (button) {
     case QuickGlobal::SystemButtonType::Unknown:
-        Q_ASSERT(false);
-        break;
+        Q_UNREACHABLE_RETURN(void(0));
     case QuickGlobal::SystemButtonType::WindowIcon:
         if (data.windowIconButton) {
             if (const auto btn = qobject_cast<QQuickAbstractButton *>(data.windowIconButton)) {

src/widgets/framelesswidgetshelper.cpp

@@ -689,8 +689,7 @@ void FramelessWidgetsHelperPrivate::setSystemButtonState(const SystemButtonType
     QWidget *widgetButton = nullptr;
     switch (button) {
     case SystemButtonType::Unknown:
-        Q_ASSERT(false);
-        break;
+        Q_UNREACHABLE_RETURN(void(0));
     case SystemButtonType::WindowIcon:
         if (data.windowIconButton) {
             widgetButton = data.windowIconButton;
@@ -843,8 +842,7 @@ void FramelessWidgetsHelperPrivate::setSystemButton(QWidget *widget, const Syste
     }
     switch (buttonType) {
     case SystemButtonType::Unknown:
-        Q_ASSERT(false);
-        break;
+        Q_UNREACHABLE_RETURN(void(0));
     case SystemButtonType::WindowIcon:
         data->windowIconButton = widget;
         break;