Add missing QUtf8StringView relational operators

Add QU8SV vs QSV, QU8SV vs QChar, and QU8SV vs char16_t relational
operators.

This allows to get rid of the dummy relational operators in
tst_qstringapisymmetry.

Task-number: QTBUG-117661
Change-Id: If95d7418efd13c505ed0e3bef748b86ff55e623a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/text/qstring.h

@@ -1141,12 +1141,29 @@ ushort QStringView::toUShort(bool *ok, int base) const
 // QUtf8StringView inline members that require QStringView:
 //
 
+template <bool UseChar8T>
+int QBasicUtf8StringView<UseChar8T>::compare(QChar other, Qt::CaseSensitivity cs) const noexcept
+{
+    return QtPrivate::compareStrings(*this, QStringView(&other, 1), cs);
+}
+
 template <bool UseChar8T>
 int QBasicUtf8StringView<UseChar8T>::compare(QStringView other, Qt::CaseSensitivity cs) const noexcept
 {
     return QtPrivate::compareStrings(*this, other, cs);
 }
 
+template <bool UseChar8T>
+[[nodiscard]] bool QBasicUtf8StringView<UseChar8T>::equal(QChar other) const noexcept
+{
+    return QtPrivate::equalStrings(*this, QStringView(&other, 1));
+}
+
+template <bool UseChar8T>
+[[nodiscard]] bool QBasicUtf8StringView<UseChar8T>::equal(QStringView other) const noexcept
+{
+    return QtPrivate::equalStrings(*this, other);
+}
 
 //
 // QUtf8StringView inline members that require QString, QL1SV or QBA:

src/corelib/text/qutf8stringview.h

@@ -293,6 +293,8 @@ public:
         return QtPrivate::compareStrings(*this, other, cs);
     }
 
+    [[nodiscard]] int compare(QChar other,
+                              Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
     [[nodiscard]] int compare(QStringView other,
                               Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
     [[nodiscard]] int compare(QLatin1StringView other,
@@ -300,6 +302,8 @@ public:
     [[nodiscard]] int compare(const QByteArray &other,
                               Qt::CaseSensitivity cs = Qt::CaseSensitive) const noexcept;
 
+    [[nodiscard]] bool equal(QChar other) const noexcept;
+    [[nodiscard]] bool equal(QStringView other) const noexcept;
     [[nodiscard]] bool equal(QLatin1StringView other) const noexcept;
     [[nodiscard]] bool equal(const QByteArray &other) const noexcept;
 
@@ -346,6 +350,28 @@ private:
     }
     Q_DECLARE_STRONGLY_ORDERED(QBasicUtf8StringView, QLatin1StringView)
 
+    friend bool
+    comparesEqual(const QBasicUtf8StringView &lhs, const QStringView &rhs) noexcept
+    { return lhs.equal(rhs); }
+    friend Qt::strong_ordering
+    compareThreeWay(const QBasicUtf8StringView &lhs, const QStringView &rhs) noexcept
+    {
+        const int res = lhs.compare(rhs);
+        return Qt::compareThreeWay(res, 0);
+    }
+    Q_DECLARE_STRONGLY_ORDERED(QBasicUtf8StringView, QStringView)
+
+    friend bool comparesEqual(const QBasicUtf8StringView &lhs, const QChar &rhs) noexcept
+    { return lhs.equal(rhs); }
+    friend Qt::strong_ordering
+    compareThreeWay(const QBasicUtf8StringView &lhs, const QChar &rhs) noexcept
+    {
+        const int res = lhs.compare(rhs);
+        return Qt::compareThreeWay(res, 0);
+    }
+    Q_DECLARE_STRONGLY_ORDERED(QBasicUtf8StringView, QChar)
+    Q_DECLARE_STRONGLY_ORDERED(QBasicUtf8StringView, char16_t)
+
 #if !defined(QT_NO_CAST_FROM_ASCII) && !defined(QT_RESTRICTED_CAST_FROM_ASCII)
     friend bool
     comparesEqual(const QBasicUtf8StringView &lhs, const QByteArrayView &rhs) noexcept

src/corelib/text/qutf8stringview.qdoc

@@ -11,6 +11,14 @@
     \ingroup tools
     \ingroup string-processing
 
+    \compares strong
+    \compareswith strong char16_t QChar {const char16_t *} QString QStringView \
+                  QLatin1StringView
+    \endcompareswith
+    \compareswith strong {const char *} QByteArray QByteArrayView
+    The contents of byte arrays is interpreted as utf-8.
+    \endcompareswith
+
     A QUtf8StringView references a contiguous portion of a UTF-8
     string it does not own. It acts as an interface type to all kinds
     of UTF-8 string, without the need to construct a QString or

tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp

@@ -68,10 +68,6 @@ MAKE_ALL(const char*, QChar)
 
 MAKE_ALL(QChar, QByteArray)
 MAKE_ALL(QChar, const char*)
-MAKE_ALL(QChar, QUtf8StringView)
-
-MAKE_ALL(QUtf8StringView, QChar)
-MAKE_ALL(QUtf8StringView, char16_t)
 
 #undef MAKE_ALL
 #undef MAKE_RELOP
@@ -224,10 +220,8 @@ private Q_SLOTS:
     void compare_QStringView_QString() { compare_impl<QStringView, QString>(); }
     void compare_QStringView_QStringView_data() { compare_data(); }
     void compare_QStringView_QStringView() { compare_impl<QStringView, QStringView>(); }
-#ifdef NOT_YET_IMPLEMENTED
     void compare_QStringView_QUtf8StringView_data() { compare_data(); }
     void compare_QStringView_QUtf8StringView() { compare_impl<QStringView, QUtf8StringView>(); }
-#endif
     void compare_QStringView_QLatin1String_data() { compare_data(); }
     void compare_QStringView_QLatin1String() { compare_impl<QStringView, QLatin1String>(); }
     void compare_QStringView_QByteArray_data() { compare_data(); }