Partially revert "QLabel: cleanup QLabelPrivate"

This partially reverts commit 8bd532b1e.

Replacing the std::optional's with real objects led to unwanted
extra allocations, some even in the destructor.

Change-Id: Ib9f949b7d93352c9027ec8a162741d7830e9ec72
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 6f62f25daffafab750f84aec2b90e129e14c2cd9)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/widgets/widgets/qlabel.cpp

@@ -138,7 +138,9 @@ QLabelPrivate::~QLabelPrivate()
 QPicture QLabel::picture() const
 {
     Q_D(const QLabel);
-    return d->picture;
+    if (d->picture)
+        return *(d->picture);
+    return QPicture();
 }
 #endif // QT_NO_PICTURE
 
@@ -302,7 +304,7 @@ void QLabel::clear()
 void QLabel::setPixmap(const QPixmap &pixmap)
 {
     Q_D(QLabel);
-    if (d->pixmap.cacheKey() != pixmap.cacheKey()) {
+    if (!d->pixmap || d->pixmap->cacheKey() != pixmap.cacheKey()) {
         d->clearContents();
         d->pixmap = pixmap;
     }
@@ -313,7 +315,9 @@ void QLabel::setPixmap(const QPixmap &pixmap)
 QPixmap QLabel::pixmap() const
 {
     Q_D(const QLabel);
-    return d->pixmap;
+    if (d->pixmap)
+        return *(d->pixmap);
+    return QPixmap();
 }
 
 /*!
@@ -521,12 +525,12 @@ QSize QLabelPrivate::sizeForWidth(int w) const
     int vextra = hextra;
     QFontMetrics fm = q->fontMetrics();
 
-    if (!pixmap.isNull()) {
-        br = pixmap.rect();
-        br.setSize(pixmap.deviceIndependentSize().toSize());
+    if (pixmap && !pixmap->isNull()) {
+        br = pixmap->rect();
+        br.setSize(pixmap->deviceIndependentSize().toSize());
 #ifndef QT_NO_PICTURE
-    } else if (!picture.isNull()) {
-        br = picture.boundingRect();
+    } else if (picture && !picture->isNull()) {
+        br = picture->boundingRect();
 #endif
 #if QT_CONFIG(movie)
     } else if (movie && !movie->currentPixmap().isNull()) {
@@ -1021,15 +1025,15 @@ void QLabel::paintEvent(QPaintEvent *)
         }
     } else
 #ifndef QT_NO_PICTURE
-    if (!d->picture.isNull()) {
-        QRect br = d->picture.boundingRect();
+    if (d->picture) {
+        QRect br = d->picture->boundingRect();
         int rw = br.width();
         int rh = br.height();
         if (d->scaledcontents) {
             painter.save();
             painter.translate(cr.x(), cr.y());
             painter.scale((double)cr.width()/rw, (double)cr.height()/rh);
-            painter.drawPicture(-br.x(), -br.y(), d->picture);
+            painter.drawPicture(-br.x(), -br.y(), *d->picture);
             painter.restore();
         } else {
             int xo = 0;
@@ -1042,25 +1046,25 @@ void QLabel::paintEvent(QPaintEvent *)
                 xo = cr.width()-rw;
             else if (align & Qt::AlignHCenter)
                 xo = (cr.width()-rw)/2;
-            painter.drawPicture(cr.x()+xo-br.x(), cr.y()+yo-br.y(), d->picture);
+            painter.drawPicture(cr.x()+xo-br.x(), cr.y()+yo-br.y(), *d->picture);
         }
     } else
 #endif
-    if (!d->pixmap.isNull()) {
+    if (d->pixmap && !d->pixmap->isNull()) {
         QPixmap pix;
         const qreal dpr = devicePixelRatio();
-        if (d->scaledcontents || dpr != d->pixmap.devicePixelRatio()) {
+        if (d->scaledcontents || dpr != d->pixmap->devicePixelRatio()) {
             QSize scaledSize = d->scaledcontents ? (cr.size() * dpr)
-                               : (d->pixmap.size() * (dpr / d->pixmap.devicePixelRatio()));
-            if (d->scaledpixmap.size() != scaledSize) {
+                               : (d->pixmap->size() * (dpr / d->pixmap->devicePixelRatio()));
+            if (!d->scaledpixmap || d->scaledpixmap->size() != scaledSize) {
                 d->scaledpixmap =
-                        d->pixmap.scaled(scaledSize,
-                                         Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
-                d->scaledpixmap.setDevicePixelRatio(dpr);
+                        d->pixmap->scaled(scaledSize,
+                                          Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
+                d->scaledpixmap->setDevicePixelRatio(dpr);
             }
-            pix = d->scaledpixmap;
+            pix = *d->scaledpixmap;
         } else
-            pix = d->pixmap;
+            pix = *d->pixmap;
         QStyleOption opt;
         opt.initFrom(this);
         if (!isEnabled())
@@ -1260,10 +1264,10 @@ void QLabelPrivate::clearContents()
     hasShortcut = false;
 
 #ifndef QT_NO_PICTURE
-    picture = QPicture();
+    picture.reset();
 #endif
-    scaledpixmap = QPixmap();
-    pixmap = QPixmap();
+    scaledpixmap.reset();
+    pixmap.reset();
 
     text.clear();
     Q_Q(QLabel);
@@ -1407,7 +1411,7 @@ void QLabel::setScaledContents(bool enable)
         return;
     d->scaledcontents = enable;
     if (!enable)
-        d->scaledpixmap = QPixmap();
+        d->scaledpixmap.reset();
     update(contentsRect());
 }
 

src/widgets/widgets/qlabel_p.h

@@ -35,6 +35,7 @@
 #include <QtCore/qpointer.h>
 
 #include <array>
+#include <optional>
 
 QT_BEGIN_NAMESPACE
 
@@ -84,10 +85,10 @@ public:
     mutable QSize sh;
     mutable QSize msh;
     QString text;
-    QPixmap pixmap;
-    QPixmap scaledpixmap;
+    std::optional<QPixmap> pixmap;
+    std::optional<QPixmap> scaledpixmap;
 #ifndef QT_NO_PICTURE
-    QPicture picture;
+    std::optional<QPicture> picture;
 #endif
 #if QT_CONFIG(movie)
     QPointer<QMovie> movie;