QStyleSheetStyle: optimize away triple key lookup

Instead of contains()/value()/remove(), all of which perform a new
lookup, and a new application of qHash(), get an iterator using
find(), deref it, then pass it to erase().

Also add some optimistic std::move().

Change-Id: I27a623dcd974de9c67d11d030e9b98d7598efc93
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/src/widgets/styles/qstylesheetstyle.cpp b/src/widgets/styles/qstylesheetstyle.cpp
index 9be19b2679..65894a6dde 100644
--- a/src/widgets/styles/qstylesheetstyle.cpp
+++ b/src/widgets/styles/qstylesheetstyle.cpp
@@ -2607,9 +2607,10 @@ void QStyleSheetStyle::unsetPalette(QWidget *w)
     const bool useStyleSheetPropagationInWidgetStyles =
         QCoreApplication::testAttribute(Qt::AA_UseStyleSheetPropagationInWidgetStyles);
 
-    if (styleSheetCaches->customPaletteWidgets.contains(w)) {
-        QPair<QPalette, uint> p = styleSheetCaches->customPaletteWidgets.value(w);
-        styleSheetCaches->customPaletteWidgets.remove(w);
+    const auto it = styleSheetCaches->customPaletteWidgets.find(w);
+    if (it != styleSheetCaches->customPaletteWidgets.end()) {
+        QPair<QPalette, uint> p = std::move(*it);
+        styleSheetCaches->customPaletteWidgets.erase(it);
 
         QPalette original = p.first;
 
@@ -2649,9 +2650,10 @@ void QStyleSheetStyle::unsetPalette(QWidget *w)
 
 void QStyleSheetStyle::unsetStyleSheetFont(QWidget *w) const
 {
-    if (styleSheetCaches->customFontWidgets.contains(w)) {
-        QPair<QFont, uint> f = styleSheetCaches->customFontWidgets.value(w);
-        styleSheetCaches->customFontWidgets.remove(w);
+    const auto it = styleSheetCaches->customFontWidgets.find(w);
+    if (it != styleSheetCaches->customFontWidgets.end()) {
+        QPair<QFont, uint> f = std::move(*it);
+        styleSheetCaches->customFontWidgets.erase(it);
 
         QFont original = f.first;
         original.resolve(original.resolve() & f.second);