QWidget: replace manual memory management with unique_ptr [6/N]: extra

Had to port a lot of caching temporaries, too. Decided to leave them as
crefs to unique_ptr to catch any mischief users may be doing with the
raw pointer instead (like deleting it).

Also fixed a use of 0 as nullptr (by standardizing on pointer-to-bool
conversion, as is done everywhere else in qwidget.cpp), and made one
impregnable if condition readable.

Change-Id: Ifdc240bf352c52de0bc3c186fa7a5f4cb2882dd0
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

4 files changed, 19 insertions, 21 deletions

diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index 94b14ecb4f..629c696544 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -3388,7 +3388,7 @@ bool QApplication::notify(QObject *receiver, QEvent *e)
 #if QT_CONFIG(graphicsview)
             // QGraphicsProxyWidget handles its own propagation,
             // and we must not change QDragManagers currentTarget.
-            QWExtra *extra = w->window()->d_func()->extra;
+            const auto &extra = w->window()->d_func()->extra;
             if (extra && extra->proxyWidget) {
                 res = d->notify_helper(w, dragEvent);
                 break;
@@ -3416,7 +3416,7 @@ bool QApplication::notify(QObject *receiver, QEvent *e)
 #if QT_CONFIG(graphicsview)
             // QGraphicsProxyWidget handles its own propagation,
             // and we must not change QDragManagers currentTarget.
-            QWExtra *extra = w->window()->d_func()->extra;
+            const auto &extra = w->window()->d_func()->extra;
             bool isProxyWidget = extra && extra->proxyWidget;
             if (!isProxyWidget)
 #endif
diff --git a/src/widgets/kernel/qshortcut.cpp b/src/widgets/kernel/qshortcut.cpp
index a4ebcdfc84..39b08dbc1e 100644
--- a/src/widgets/kernel/qshortcut.cpp
+++ b/src/widgets/kernel/qshortcut.cpp
@@ -178,7 +178,7 @@ static bool correctWidgetContext(Qt::ShortcutContext context, QWidget *w, QWidge
     // Below is Qt::WindowShortcut context
     QWidget *tlw = w->window();
 #if QT_CONFIG(graphicsview)
-    if (auto topData = static_cast<QWidgetPrivate *>(QObjectPrivate::get(tlw))->extra) {
+    if (auto topData = static_cast<QWidgetPrivate *>(QObjectPrivate::get(tlw))->extra.get()) {
         if (topData->proxyWidget) {
             bool res = correctGraphicsWidgetContext(context, topData->proxyWidget, active_window);
             return res;
diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index 066dfaa183..2edbe05e32 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -148,7 +148,6 @@ extern QDesktopWidget *qt_desktopWidget; // qapplication.cpp
 
 QWidgetPrivate::QWidgetPrivate(int version)
     : QObjectPrivate(version)
-      , extra(0)
       , focus_next(0)
       , focus_prev(0)
       , focus_child(0)
@@ -1553,7 +1552,7 @@ QWidget::~QWidget()
         while (w->d_func()->extra && w->d_func()->extra->focus_proxy)
             w = w->d_func()->extra->focus_proxy;
         QWidget *window = w->window();
-        QWExtra *e = window ? window->d_func()->extra : 0;
+        QWExtra *e = window ? window->d_func()->extra.get() : nullptr ;
         if (!e || !e->proxyWidget || (w->parentWidget() && w->parentWidget()->d_func()->focus_child == this))
 #endif
         clearFocus();
@@ -1732,7 +1731,7 @@ void QWidgetPrivate::createTLExtra()
 void QWidgetPrivate::createExtra()
 {
     if (!extra) {                                // if not exists
-        extra = new QWExtra;
+        extra = qt_make_unique<QWExtra>();
         extra->glContext = 0;
 #if QT_CONFIG(graphicsview)
         extra->proxyWidget = 0;
@@ -1780,9 +1779,8 @@ void QWidgetPrivate::deleteExtra()
             deleteTLSysExtra();
             // extra->topextra->backingStore destroyed in QWidgetPrivate::deleteTLSysExtra()
         }
-        delete extra;
         // extra->xic destroyed in QWidget::destroy()
-        extra = 0;
+        extra.reset();
     }
 }
 
@@ -1853,7 +1851,7 @@ QRegion QWidgetPrivate::overlappedRegion(const QRect &rect, bool breakAfterFirst
 
             const QRect siblingRect = sibling->d_func()->effectiveRectFor(sibling->data->crect);
             if (qRectIntersects(siblingRect, r)) {
-                const QWExtra *siblingExtra = sibling->d_func()->extra;
+                const auto &siblingExtra = sibling->d_func()->extra;
                 if (siblingExtra && siblingExtra->hasMask && !sibling->d_func()->graphicsEffect
                     && !siblingExtra->mask.translated(sibling->data->crect.topLeft()).intersects(r)) {
                     continue;
@@ -3858,7 +3856,7 @@ QSize QWidget::sizeIncrement() const
 QSize QWidget::baseSize() const
 {
     Q_D(const QWidget);
-    return (d->extra != 0 && d->extra->topextra != 0)
+    return (d->extra && d->extra->topextra)
         ? QSize(d->extra->topextra->basew, d->extra->topextra->baseh)
         : QSize(0, 0);
 }
@@ -5858,7 +5856,7 @@ QPixmap QWidgetEffectSourcePrivate::pixmap(Qt::CoordinateSystem system, QPoint *
 QGraphicsProxyWidget *QWidgetPrivate::nearestGraphicsProxyWidget(const QWidget *origin)
 {
     if (origin) {
-        QWExtra *extra = origin->d_func()->extra;
+        const auto &extra = origin->d_func()->extra;
         if (extra && extra->proxyWidget)
             return extra->proxyWidget;
         return nearestGraphicsProxyWidget(origin->parentWidget());
@@ -6404,7 +6402,7 @@ bool QWidget::hasFocus() const
         w = w->d_func()->extra->focus_proxy;
 #if QT_CONFIG(graphicsview)
     if (QWidget *window = w->window()) {
-        QWExtra *e = window->d_func()->extra;
+        const auto &e = window->d_func()->extra;
         if (e && e->proxyWidget && e->proxyWidget->hasFocus() && window->focusWidget() == w)
             return true;
     }
@@ -6465,7 +6463,7 @@ void QWidget::setFocus(Qt::FocusReason reason)
 
 #if QT_CONFIG(graphicsview)
     QWidget *previousProxyFocus = 0;
-    if (QWExtra *topData = window()->d_func()->extra) {
+    if (const auto &topData = window()->d_func()->extra) {
         if (topData->proxyWidget && topData->proxyWidget->hasFocus()) {
             previousProxyFocus = topData->proxyWidget->widget()->focusWidget();
             if (previousProxyFocus && previousProxyFocus->focusProxy())
@@ -6478,7 +6476,7 @@ void QWidget::setFocus(Qt::FocusReason reason)
 
 #if QT_CONFIG(graphicsview)
     // Update proxy state
-    if (QWExtra *topData = window()->d_func()->extra) {
+    if (const auto &topData = window()->d_func()->extra) {
         if (topData->proxyWidget && !topData->proxyWidget->hasFocus()) {
             f->d_func()->updateFocusChild();
             topData->proxyWidget->d_func()->focusFromWidgetToProxy = 1;
@@ -6519,7 +6517,7 @@ void QWidget::setFocus(Qt::FocusReason reason)
         }
 #endif
 #if QT_CONFIG(graphicsview)
-        if (QWExtra *topData = window()->d_func()->extra) {
+        if (const auto &topData = window()->d_func()->extra) {
             if (topData->proxyWidget) {
                 if (previousProxyFocus && previousProxyFocus != f) {
                     // Send event to self
@@ -6532,7 +6530,7 @@ void QWidget::setFocus(Qt::FocusReason reason)
                 if (!isHidden()) {
 #if QT_CONFIG(graphicsview)
                     // Update proxy state
-                    if (QWExtra *topData = window()->d_func()->extra)
+                    if (const auto &topData = window()->d_func()->extra)
                         if (topData->proxyWidget && topData->proxyWidget->hasFocus())
                             topData->proxyWidget->d_func()->updateProxyInputMethodAcceptanceFromWidget();
 #endif
@@ -6669,7 +6667,7 @@ void QWidget::clearFocus()
     }
 
 #if QT_CONFIG(graphicsview)
-    QWExtra *topData = d_func()->extra;
+    const auto &topData = d_func()->extra;
     if (topData && topData->proxyWidget)
         topData->proxyWidget->clearFocus();
 #endif
@@ -6835,7 +6833,7 @@ bool QWidget::isActiveWindow() const
         return true;
 
 #if QT_CONFIG(graphicsview)
-    if (QWExtra *tlwExtra = tlw->d_func()->extra) {
+    if (const auto &tlwExtra = tlw->d_func()->extra) {
         if (isVisible() && tlwExtra->proxyWidget)
             return tlwExtra->proxyWidget->isActiveWindow();
     }
@@ -10325,7 +10323,7 @@ void QWidget::setSizePolicy(QSizePolicy policy)
     d->size_policy = policy;
 
 #if QT_CONFIG(graphicsview)
-    if (QWExtra *extra = d->extra) {
+    if (const auto &extra = d->extra) {
         if (extra->proxyWidget)
             extra->proxyWidget->setSizePolicy(policy);
     }
diff --git a/src/widgets/kernel/qwidget_p.h b/src/widgets/kernel/qwidget_p.h
index b4a9d283db..687e8bef09 100644
--- a/src/widgets/kernel/qwidget_p.h
+++ b/src/widgets/kernel/qwidget_p.h
@@ -669,7 +669,7 @@ public:
 
     // Variables.
     // Regular pointers (keep them together to avoid gaps on 64 bit architectures).
-    QWExtra *extra;
+    std::unique_ptr<QWExtra> extra;
     QWidget *focus_next;
     QWidget *focus_prev;
     QWidget *focus_child;
@@ -945,7 +945,7 @@ public:
 
 inline QWExtra *QWidgetPrivate::extraData() const
 {
-    return extra;
+    return extra.get();
 }
 
 inline QTLWExtra *QWidgetPrivate::topData() const