Frameworks/QStringView porting cheat sheet

From KDE Community Wiki

According to this upstream Git repo, QStringRef will be moved to a qt5compat module in Qt6, which means KDE code needs to be ported away from it. The candidate replacement is QStringView. Since the latter's API is apparently still being modified upstream, not all methods are available in Qt 5.13 (which is the version that KDE Frameworks require at the time of writing this), this is a "cheat sheet" of sorts, listing all the QStringView methods that aren't available in Qt 5.13, or that have a different behaviour than the QString counterpart.

See the relevant discussion in https://phabricator.kde.org/T13913 (some of those methods introduced in Qt 5.15 as porting aid may be slow/ugly).

Method Notes
QString arg(Args &&... args) const Since Qt5.14
int compare(QLatin1String l1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
int compare(QChar ch) const Since Qt5.14
int compare(QChar ch, Qt::CaseSensitivity cs) const Since Qt5.14
bool contains(QChar c, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
bool contains(QStringView str, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
bool contains(QLatin1String l1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
qsizetype count(QChar ch, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.15.2
qsizetype count(QStringView str, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.15.2
qsizetype indexOf(QChar c, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
qsizetype indexOf(QStringView str, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
qsizetype indexOf(QLatin1String l1, qsizetype from = 0, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
bool isValidUtf16() const Since Qt5.15
qsizetype lastIndexOf(QChar c, qsizetype from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
qsizetype lastIndexOf(QStringView str, qsizetype from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
qsizetype lastIndexOf(QLatin1String l1, qsizetype from = -1, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.14
QStringView left(qsizetype length) const Until 5.15.1, the behavior was undefined when length < 0 or length > size(). Since 5.15.2, the behavior is compatible with QString::left()
QStringView mid(qsizetype start) const Until 5.15.1, the behavior was undefined when start < 0 or start > size(). Since 5.15.2, the behavior is compatible with QString::mid()
QStringView mid(qsizetype start, qsizetype length) const Until 5.15.1, the behavior was undefined when start < 0 or start > size(). Since 5.15.2, the behavior is compatible with QString::mid()
QStringView right(qsizetype length) const Until 5.15.1, the behavior was undefined when length < 0 or length > size(). Since 5.15.2, the behavior is compatible with QString::right()
QList<QStringView> split(QStringView sep, Qt::SplitBehavior behavior = Qt::KeepEmptyParts, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.15.2
QList<QStringView> split(QChar sep, Qt::SplitBehavior behavior = Qt::KeepEmptyParts, Qt::CaseSensitivity cs = Qt::CaseSensitive) const Since Qt5.15.2
QList<QStringView> split(const QRegularExpression &sep, Qt::SplitBehavior behavior = Qt::KeepEmptyParts) const Since Qt5.15.2
double toDouble(bool *ok = nullptr) const Since Qt5.15.2
float toFloat(bool *ok = nullptr) const Since Qt5.15.2
int toInt(bool *ok = nullptr, int base = 10) const Since Qt5.15.2
long toLong(bool *ok = nullptr, int base = 10) const Since Qt5.15.2
qlonglong toLongLong(bool *ok = nullptr, int base = 10) const Since Qt5.15.2
short toShort(bool *ok = nullptr, int base = 10) const Since Qt5.15.2
uint toUInt(bool *ok = nullptr, int base = 10) const Since Qt5.15.2
ulong toULong(bool *ok = nullptr, int base = 10) const Since Qt5.15.2
qulonglong toULongLong(bool *ok = nullptr, int base = 10) const Since Qt5.15.2
ushort toUShort(bool *ok = nullptr, int base = 10) const Since Qt5.15.2
int toWCharArray(wchar_t *array) const Since Qt5.14