diff options
| author | David Faure <david.faure@kdab.com> | 2019-12-02 21:16:24 +0100 |
|---|---|---|
| committer | David Faure <david.faure@kdab.com> | 2019-12-05 14:06:02 +0100 |
| commit | aa504fc2fa764b44d37d9629b9ddf1f114210759 (patch) | |
| tree | 20b70546ad8b7e272608c3456241a793c4a0ca39 /src/corelib | |
| parent | 97ac281c1d70dcfbb137e5a83e24a747e9510116 (diff) | |
Optimize qLastIndexOf<QString> to not detach the QString
The call to data() on a non-const QString led to a detach(), which is
unexpected and unwanted from QString::lastIndexOf() const.
Found by looking at why QFileSystemEntry::fileName() was expensive, in
the hotspot profiler.
The solution is to instanciate QLastIndexOf with QStringView() rather
than QString(). I added a deleted QString overload to make sure nobody
ever instanciates it with a QString argument again.
Change-Id: I06a1b2f937425e83f0779eb215e099aef78c50a7
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src/corelib')
| -rw-r--r-- | src/corelib/text/qstring.cpp | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp index 51aa0b7512..4d83f19db7 100644 --- a/src/corelib/text/qstring.cpp +++ b/src/corelib/text/qstring.cpp @@ -146,6 +146,9 @@ qsizetype qFindStringBoyerMoore(QStringView haystack, qsizetype from, QStringVie static inline qsizetype qFindChar(QStringView str, QChar ch, qsizetype from, Qt::CaseSensitivity cs) noexcept; template <typename Haystack> static inline qsizetype qLastIndexOf(Haystack haystack, QChar needle, qsizetype from, Qt::CaseSensitivity cs) noexcept; +template <> +inline qsizetype qLastIndexOf(QString haystack, QChar needle, + qsizetype from, Qt::CaseSensitivity cs) noexcept = delete; // unwanted, would detach static inline qsizetype qt_string_count(QStringView haystack, QStringView needle, Qt::CaseSensitivity cs); static inline qsizetype qt_string_count(QStringView haystack, QChar needle, Qt::CaseSensitivity cs); @@ -3817,7 +3820,7 @@ int QString::indexOf(const QStringRef &str, int from, Qt::CaseSensitivity cs) co int QString::lastIndexOf(const QString &str, int from, Qt::CaseSensitivity cs) const { // ### Qt6: qsizetype - return int(QtPrivate::lastIndexOf(*this, from, str, cs)); + return int(QtPrivate::lastIndexOf(QStringView(*this), from, str, cs)); } #endif // QT_STRINGVIEW_LEVEL < 2 @@ -3856,7 +3859,7 @@ int QString::lastIndexOf(QLatin1String str, int from, Qt::CaseSensitivity cs) co int QString::lastIndexOf(QChar ch, int from, Qt::CaseSensitivity cs) const { // ### Qt6: qsizetype - return int(qLastIndexOf(*this, ch, from, cs)); + return int(qLastIndexOf(QStringView(*this), ch, from, cs)); } #if QT_STRINGVIEW_LEVEL < 2 |