From 75663be3b580d1b763c354f69f7828a0c32536d9 Mon Sep 17 00:00:00 2001
From: Axel Spoerl <axel.spoerl@qt.io>
Date: Fri, 28 Mar 2025 09:53:03 +0100
Subject: [PATCH] QXdgDesktopPortalTheme: Refactor base theme creation loop
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The search for a base theme was handled in 2 separate loops.
Combine those in sync with QGuiApplication.
Make list of theme names const, as it doesn't and mustn't change.

Pick-to: 6.8 6.5
Task-number: QTBUG-134702
Change-Id: If4ae8212bbefa2934639feec983b94e8e2d6b168
Reviewed-by: Jan Grulich <jgrulich@redhat.com>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
(cherry picked from commit 63ba867dddd5bfe3827f48eb24884c534c80541a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 .../qxdgdesktopportaltheme.cpp                | 23 ++++++-------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/src/plugins/platformthemes/xdgdesktopportal/qxdgdesktopportaltheme.cpp b/src/plugins/platformthemes/xdgdesktopportal/qxdgdesktopportaltheme.cpp
index 58b613baeb2..2b3fb2b9494 100644
--- a/src/plugins/platformthemes/xdgdesktopportal/qxdgdesktopportaltheme.cpp
+++ b/src/plugins/platformthemes/xdgdesktopportal/qxdgdesktopportaltheme.cpp
@@ -84,28 +84,19 @@ QXdgDesktopPortalTheme::QXdgDesktopPortalTheme()
 {
     Q_D(QXdgDesktopPortalTheme);
 
-    QStringList themeNames;
-    themeNames += QGuiApplicationPrivate::platform_integration->themeNames();
-    // 1) Look for a theme plugin.
-    for (const QString &themeName : std::as_const(themeNames)) {
+    const QStringList themeNames = QGuiApplicationPrivate::platform_integration->themeNames();
+    for (const QString &themeName : themeNames) {
         if (QXdgDesktopPortalTheme::isXdgPlugin(themeName))
             continue;
+        // 1) Look for a theme plugin.
         d->baseTheme = QPlatformThemeFactory::create(themeName, nullptr);
         if (d->baseTheme)
             break;
-    }
 
-    // 2) If no theme plugin was found ask the platform integration to
-    // create a theme
-    if (!d->baseTheme) {
-        for (const QString &themeName : std::as_const(themeNames)) {
-            if (QXdgDesktopPortalTheme::isXdgPlugin(themeName))
-                continue;
-            d->baseTheme = QGuiApplicationPrivate::platform_integration->createPlatformTheme(themeName);
-            if (d->baseTheme)
-                break;
-        }
-        // No error message; not having a theme plugin is allowed.
+        // 2) If no theme plugin was found ask the platform integration to create a theme
+        d->baseTheme = QGuiApplicationPrivate::platform_integration->createPlatformTheme(themeName);
+        if (d->baseTheme)
+            break;
     }
 
     // 3) Fall back on the built-in "null" platform theme.