Plugins: optimize string usage

Prefer QStringRef methods to avoid allocations.

Use startsWith/endsWith rather than comparing substrings;
and avoid substrings where references suffice.

Use new QStringList::join(QL1S).

Change-Id: I46c44aca96578633370006d613eb0ac13f7cfc03
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp b/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp
index 42d3c1f193..2030732e4b 100644
--- a/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp
+++ b/src/plugins/platformthemes/gtk3/qgtk3dialoghelpers.cpp
@@ -463,10 +463,10 @@ void QGtk3FileDialogHelper::setNameFilters(const QStringList &filters)
 
     foreach (const QString &filter, filters) {
         GtkFileFilter *gtkFilter = gtk_file_filter_new();
-        const QString name = filter.left(filter.indexOf(QLatin1Char('(')));
+        const QStringRef name = filter.leftRef(filter.indexOf(QLatin1Char('(')));
         const QStringList extensions = cleanFilterList(filter);
 
-        gtk_file_filter_set_name(gtkFilter, name.isEmpty() ? extensions.join(QStringLiteral(", ")).toUtf8() : name.toUtf8());
+        gtk_file_filter_set_name(gtkFilter, name.isEmpty() ? extensions.join(QLatin1String(", ")).toUtf8() : name.toUtf8());
         foreach (const QString &ext, extensions)
             gtk_file_filter_add_pattern(gtkFilter, ext.toUtf8());