From 7ec5cba6de08f8988df0465d4084d6d512278a24 Mon Sep 17 00:00:00 2001
From: Edward Welbourne <edward.welbourne@qt.io>
Date: Tue, 14 Jul 2020 13:59:40 +0200
Subject: [PATCH] QSystemLocalePrivate::substituteDigits(): change to move
 semantics

Rather than passing an in-out reference parameter and ignoring the
return (of that parameter) use an actual rvalue ref parameter and move
the value through the function, to make it easier for compilers to
see how to optimize it.

Change-Id: Ie239400345da012d8fb8a731394f1687b8b62430
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/text/qlocale_win.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/corelib/text/qlocale_win.cpp b/src/corelib/text/qlocale_win.cpp
index 8c55e04cc6..a1a1e1c43c 100644
--- a/src/corelib/text/qlocale_win.cpp
+++ b/src/corelib/text/qlocale_win.cpp
@@ -133,7 +133,7 @@ private:
     int getTimeFormat(DWORD flags, const SYSTEMTIME *date, LPCWSTR format, LPWSTR data, int size);
 
     SubstitutionType substitution();
-    QString &substituteDigits(QString &string);
+    QString substituteDigits(QString &&string);
 
     static QString winToQtFormat(QStringView sys_fmt);
 
@@ -230,7 +230,7 @@ QSystemLocalePrivate::SubstitutionType QSystemLocalePrivate::substitution()
     return substitutionType;
 }
 
-QString &QSystemLocalePrivate::substituteDigits(QString &string)
+QString QSystemLocalePrivate::substituteDigits(QString &&string)
 {
     zeroDigit(); // Ensure zero is set.
     switch (zero.size()) {
@@ -261,7 +261,7 @@ QString &QSystemLocalePrivate::substituteDigits(QString &string)
     case 0: // Apparently this locale info was not available.
         break;
     }
-    return string;
+    return std::move(string);
 }
 
 QVariant QSystemLocalePrivate::zeroDigit()
@@ -400,7 +400,7 @@ QVariant QSystemLocalePrivate::toString(QDate date, QLocale::FormatType type)
     if (getDateFormat(flags, &st, NULL, buf, 255)) {
         QString format = QString::fromWCharArray(buf);
         if (substitution() == SAlways)
-            substituteDigits(format);
+            format = substituteDigits(std::move(format));
         return format;
     }
     return QString();
@@ -424,7 +424,7 @@ QVariant QSystemLocalePrivate::toString(QTime time, QLocale::FormatType type)
     if (getTimeFormat(flags, &st, NULL, buf, 255)) {
         QString format = QString::fromWCharArray(buf);
         if (substitution() == SAlways)
-            substituteDigits(format);
+            format = substituteDigits(std::move(format));
         return format;
     }
     return QString();
@@ -585,7 +585,7 @@ QVariant QSystemLocalePrivate::toCurrencyString(const QSystemLocale::CurrencyToS
 
     value = QString::fromWCharArray(out.data());
     if (substitution() == SAlways)
-        substituteDigits( value);
+        value = substituteDigits(std::move(value));
     return value;
 }