From daa7f5375c58464bbe92744599f1e2258445e259 Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Sun, 25 Feb 2018 17:41:11 -0800 Subject: q{,Utf8}Printable: avoid creating a copy of a QString MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We have this QString() constructor call to permit things that convert to QString but aren't QString to be used in qPrintable, like a QStringBuilder-powered fast operator+ expression, like: qPrintable(string1 + ": " + string2) Unfortunately, it meant that we unnecessarily created a QString copy if the input was already QString. Change-Id: Iecab8770aa5840aba8edfffd1516bc94cec791a9 Reviewed-by: Olivier Goffart (Woboq GmbH) Reviewed-by: Oswald Buddenhagen Reviewed-by: Mårten Nordheim Reviewed-by: Thiago Macieira --- src/corelib/global/qglobal.h | 5 +++-- src/corelib/tools/qstring.h | 6 ++++++ 2 files changed, 9 insertions(+), 2 deletions(-) (limited to 'src') diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h index 33885021ba..e31d4d9ad7 100644 --- a/src/corelib/global/qglobal.h +++ b/src/corelib/global/qglobal.h @@ -747,12 +747,13 @@ Q_CORE_EXPORT Q_DECL_CONST_FUNCTION bool qSharedBuild() Q_DECL_NOTHROW; # define QT_DEBUG #endif +// QtPrivate::asString defined in qstring.h #ifndef qPrintable -# define qPrintable(string) QString(string).toLocal8Bit().constData() +# define qPrintable(string) QtPrivate::asString(string).toLocal8Bit().constData() #endif #ifndef qUtf8Printable -# define qUtf8Printable(string) QString(string).toUtf8().constData() +# define qUtf8Printable(string) QtPrivate::asString(string).toUtf8().constData() #endif /* diff --git a/src/corelib/tools/qstring.h b/src/corelib/tools/qstring.h index 0138ae4098..b8f4d49831 100644 --- a/src/corelib/tools/qstring.h +++ b/src/corelib/tools/qstring.h @@ -1857,6 +1857,12 @@ QT_DEPRECATED inline QString escape(const QString &plain) { #endif } +namespace QtPrivate { +// used by qPrintable() and qUtf8Printable() macros +inline const QString &asString(const QString &s) { return s; } +inline QString &&asString(QString &&s) { return std::move(s); } +} + QT_END_NAMESPACE #if defined(QT_USE_FAST_OPERATOR_PLUS) || defined(QT_USE_QSTRINGBUILDER) -- cgit v1.2.3