Add QStringView vs byte array relational operators

... by using the new comparison helper macors.

Note that by providing helper functions for QByteArrayView,
we can support all three types: QByteArray, QByteArrayView, and
const char *.

Use the regular QT_NO_CAST_FROM_ASCII and
QT_RESTRICTED_CAST_FROM_ASCII guards to disable the operators
if the cast from ASCII is forbidden.
Also use QT_ASCII_CAST_WARN on each operator.

This allows to enable related tests in tst_qstringapisymmetry.

Task-number: QTBUG-117661
Task-number: QTBUG-108805
Change-Id: I0d77c30245d8b5ac4b8cfd98d650c1885aca2005
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 42 insertions, 6 deletions

diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp
index ea74cb9d72..d3bb1d92d1 100644
--- a/src/corelib/text/qstring.cpp
+++ b/src/corelib/text/qstring.cpp
@@ -6588,6 +6588,28 @@ int QString::compare_helper(const QChar *data1, qsizetype length1, const char *d
     \internal
     \since 6.8
 */
+bool QStringView::equal_helper(QStringView sv, const char *data, qsizetype len)
+{
+    Q_ASSERT(len >= 0);
+    Q_ASSERT(data || len == 0);
+    return QtPrivate::equalStrings(sv, QUtf8StringView(data, len));
+}
+
+/*!
+    \internal
+    \since 6.8
+*/
+int QStringView::compare_helper(QStringView sv, const char *data, qsizetype len)
+{
+    Q_ASSERT(len >= 0);
+    Q_ASSERT(data || len == 0);
+    return QtPrivate::compareStrings(sv, QUtf8StringView(data, len));
+}
+
+/*!
+    \internal
+    \since 6.8
+*/
 bool QLatin1StringView::equal_helper(QLatin1StringView s1, const char *s2, qsizetype len) noexcept
 {
     // because qlatin1stringview.h can't include qutf8stringview.h
diff --git a/src/corelib/text/qstringview.h b/src/corelib/text/qstringview.h
index 57ae1fe869..2e099a9ba5 100644
--- a/src/corelib/text/qstringview.h
+++ b/src/corelib/text/qstringview.h
@@ -5,6 +5,7 @@
 #define QSTRINGVIEW_H
 
 #include <QtCore/qchar.h>
+#include <QtCore/qcompare.h>
 #include <QtCore/qbytearray.h>
 #include <QtCore/qstringliteral.h>
 #include <QtCore/qstringalgorithms.h>
@@ -431,6 +432,23 @@ private:
 
     constexpr int compare_single_char_helper(int diff) const noexcept
     { return diff ? diff : size() > 1 ? 1 : 0; }
+
+    Q_CORE_EXPORT static bool equal_helper(QStringView sv, const char *data, qsizetype len);
+    Q_CORE_EXPORT static int compare_helper(QStringView sv, const char *data, qsizetype len);
+
+#if !defined(QT_NO_CAST_FROM_ASCII) && !defined(QT_RESTRICTED_CAST_FROM_ASCII)
+    friend bool comparesEqual(const QStringView &lhs, const QByteArrayView &rhs) noexcept
+    { return equal_helper(lhs, rhs.data(), rhs.size()); }
+    friend Qt::strong_ordering
+    compareThreeWay(const QStringView &lhs, const QByteArrayView &rhs) noexcept
+    {
+        const int res = compare_helper(lhs, rhs.data(), rhs.size());
+        return Qt::compareThreeWay(res, 0);
+    }
+    Q_DECLARE_STRONGLY_ORDERED(QStringView, QByteArrayView, QT_ASCII_CAST_WARN)
+    Q_DECLARE_STRONGLY_ORDERED(QStringView, QByteArray, QT_ASCII_CAST_WARN)
+    Q_DECLARE_STRONGLY_ORDERED(QStringView, const char *, QT_ASCII_CAST_WARN)
+#endif // !defined(QT_NO_CAST_FROM_ASCII) && !defined(QT_RESTRICTED_CAST_FROM_ASCII)
 };
 Q_DECLARE_TYPEINFO(QStringView, Q_PRIMITIVE_TYPE);
 
diff --git a/tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp b/tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp
index e1a2232b7b..7d74253407 100644
--- a/tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp
+++ b/tests/auto/corelib/text/qstringapisymmetry/tst_qstringapisymmetry.cpp
@@ -234,14 +234,12 @@ private Q_SLOTS:
 #endif
     void compare_QStringView_QLatin1String_data() { compare_data(); }
     void compare_QStringView_QLatin1String() { compare_impl<QStringView, QLatin1String>(); }
-#ifdef NOT_YET_IMPLMENTED
     void compare_QStringView_QByteArray_data() { compare_data(); }
     void compare_QStringView_QByteArray() { compare_impl<QStringView, QByteArray>(); }
     void compare_QStringView_QByteArrayView_data() { compare_data(); }
     void compare_QStringView_QByteArrayView() { compare_impl<QStringView, QByteArrayView>(); }
     void compare_QStringView_const_char_star_data() { compare_data(); }
     void compare_QStringView_const_char_star() { compare_impl<QStringView, const char *>(); }
-#endif
 
     void compare_QUtf8StringView_QChar_data() { compare_data(false); }
     void compare_QUtf8StringView_QChar() { compare_impl<QUtf8StringView, QChar>(); }
@@ -287,10 +285,8 @@ private Q_SLOTS:
     void compare_QByteArray_char16_t() { compare_impl<QByteArray, char16_t>(); }
     void compare_QByteArray_QString_data() { compare_data(); }
     void compare_QByteArray_QString() { compare_impl<QByteArray, QString>(); }
-#ifdef NOT_YET_IMPLEMENTED
     void compare_QByteArray_QStringView_data() { compare_data(); }
     void compare_QByteArray_QStringView() { compare_impl<QByteArray, QStringView>(); }
-#endif
     void compare_QByteArray_QUtf8StringView_data() { compare_data(); }
     void compare_QByteArray_QUtf8StringView() { compare_impl<QByteArray, QUtf8StringView>(); }
     void compare_QByteArray_QLatin1String_data() { compare_data(); }
@@ -308,10 +304,8 @@ private Q_SLOTS:
     void compare_QByteArrayView_char16_t() { compare_impl<QByteArrayView, char16_t>(); }
     void compare_QByteArrayView_QString_data() { compare_data(); }
     void compare_QByteArrayView_QString() { compare_impl<QByteArrayView, QString>(); }
-#ifdef NOT_YET_IMPLEMENTED
     void compare_QByteArrayView_QStringView_data() { compare_data(); }
     void compare_QByteArrayView_QStringView() { compare_impl<QByteArrayView, QStringView>(); }
-#endif
     void compare_QByteArrayView_QUtf8StringView_data() { compare_data(); }
     void compare_QByteArrayView_QUtf8StringView() { compare_impl<QByteArrayView, QUtf8StringView>(); }
     void compare_QByteArrayView_QLatin1String_data() { compare_data(); }
@@ -329,6 +323,8 @@ private Q_SLOTS:
     //void compare_const_char_star_char16_t() { compare_impl<const char *, char16_t>(); }
     void compare_const_char_star_QString_data() { compare_data(); }
     void compare_const_char_star_QString() { compare_impl<const char *, QString>(); }
+    void compare_const_char_star_QStringView_data() { compare_data(); }
+    void compare_const_char_star_QStringView() { compare_impl<const char *, QStringView>(); }
     void compare_const_char_star_QUtf8StringView_data() { compare_data(); }
     void compare_const_char_star_QUtf8StringView() { compare_impl<const char *, QUtf8StringView>(); }
     void compare_const_char_star_QLatin1String_data() { compare_data(false); }