Make QAnyStringView comparison operators hidden friends

Also add the very same operators to the QBasicUtf8StringView
class to overcome the compiler issues seen on gcc.

Fixes: QTBUG-86481
Change-Id: I12484455ebd3b7b38d4ad67c38977d76f9b3ddfa
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

3 files changed, 52 insertions, 22 deletions

diff --git a/src/corelib/text/qanystringview.h b/src/corelib/text/qanystringview.h
index 242efc6e5c..647f43f265 100644
--- a/src/corelib/text/qanystringview.h
+++ b/src/corelib/text/qanystringview.h
@@ -42,6 +42,10 @@
 #include <QtCore/qstringview.h>
 #include <QtCore/qutf8stringview.h>
 
+#ifdef __cpp_impl_three_way_comparison
+#include <compare>
+#endif
+
 QT_BEGIN_NAMESPACE
 
 template <typename, typename> class QStringBuilder;
@@ -217,7 +221,27 @@ public:
     constexpr int length() const /* not nothrow! */
     { return Q_ASSERT(int(size()) == size()), int(size()); }
 #endif
+
 private:
+    [[nodiscard]] friend inline bool operator==(QAnyStringView lhs, QAnyStringView rhs) noexcept
+    { return QAnyStringView::compare(lhs, rhs) == 0; }
+    [[nodiscard]] friend inline bool operator!=(QAnyStringView lhs, QAnyStringView rhs) noexcept
+    { return !operator==(lhs, rhs); }
+
+#ifdef __cpp_impl_three_way_comparison
+    [[nodiscard]] friend inline auto operator<=>(QAnyStringView lhs, QAnyStringView rhs) noexcept
+    { return QAnyStringView::compare(lhs, rhs) <=> 0; }
+#else
+    [[nodiscard]] friend inline bool operator<=(QAnyStringView lhs, QAnyStringView rhs) noexcept
+    { return QAnyStringView::compare(lhs, rhs) <= 0; }
+    [[nodiscard]] friend inline bool operator>=(QAnyStringView lhs, QAnyStringView rhs) noexcept
+    { return QAnyStringView::compare(lhs, rhs) >= 0; }
+    [[nodiscard]] friend inline bool operator<(QAnyStringView lhs, QAnyStringView rhs) noexcept
+    { return QAnyStringView::compare(lhs, rhs) < 0; }
+    [[nodiscard]] friend inline bool operator>(QAnyStringView lhs, QAnyStringView rhs) noexcept
+    { return QAnyStringView::compare(lhs, rhs) > 0; }
+#endif
+
     // TODO: Optimize by inverting and storing the flags in the low bits and
     //       the size in the high.
     static_assert(std::is_same_v<std::size_t, size_t>);
@@ -273,26 +297,6 @@ template <typename QStringLike, std::enable_if_t<std::disjunction_v<
 [[nodiscard]] inline QAnyStringView qToAnyStringViewIgnoringNull(const QStringLike &s) noexcept
 { return QAnyStringView(s.data(), s.size()); }
 
-
-#define Q_ANY_SV_MAKE_RELOP(op) \
-    [[nodiscard]] Q_ALWAYS_INLINE auto operator op (QAnyStringView lhs, QAnyStringView rhs) noexcept \
-    { return QAnyStringView::compare(lhs, rhs) op 0; } \
-    /* end */
-
-Q_ANY_SV_MAKE_RELOP(==) // size() shortcut doesn't apply for UTF-8 vs. {L1, UTF-16}
-Q_ANY_SV_MAKE_RELOP(!=)
-
-#ifdef __cpp_impl_three_way_comparison
-Q_ANY_SV_MAKE_RELOP(<=>)
-#else
-Q_ANY_SV_MAKE_RELOP(<=)
-Q_ANY_SV_MAKE_RELOP(>=)
-Q_ANY_SV_MAKE_RELOP(<)
-Q_ANY_SV_MAKE_RELOP(>)
-#endif
-
-#undef Q_ANY_SV_MAKE_RELOP
-
 QT_END_NAMESPACE
 
 #endif /* QANYSTRINGVIEW_H */
diff --git a/src/corelib/text/qstring.h b/src/corelib/text/qstring.h
index d12c96632e..5c809592e8 100644
--- a/src/corelib/text/qstring.h
+++ b/src/corelib/text/qstring.h
@@ -1042,6 +1042,11 @@ QString QBasicUtf8StringView<UseChar8T>::toString() const
     return QString::fromUtf8(data(), int(size()));
 }
 
+template<bool UseChar8T>
+inline int QBasicUtf8StringView<UseChar8T>::compare(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs,
+                                                    Qt::CaseSensitivity cs) noexcept
+{ return QAnyStringView::compare(lhs, rhs, cs); }
+
 //
 // QAnyStringView inline members that require QString:
 //
@@ -1438,7 +1443,6 @@ inline bool operator> (QLatin1String lhs, QChar rhs) noexcept { return   rhs <
 inline bool operator<=(QLatin1String lhs, QChar rhs) noexcept { return !(rhs <  lhs); }
 inline bool operator>=(QLatin1String lhs, QChar rhs) noexcept { return !(rhs >  lhs); }
 
-#if 0
 // QStringView <> QStringView
 inline bool operator==(QStringView lhs, QStringView rhs) noexcept { return lhs.size() == rhs.size() && QtPrivate::compareStrings(lhs, rhs) == 0; }
 inline bool operator!=(QStringView lhs, QStringView rhs) noexcept { return !(lhs == rhs); }
@@ -1446,7 +1450,6 @@ inline bool operator< (QStringView lhs, QStringView rhs) noexcept { return QtPri
 inline bool operator<=(QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) <= 0; }
 inline bool operator> (QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) >  0; }
 inline bool operator>=(QStringView lhs, QStringView rhs) noexcept { return QtPrivate::compareStrings(lhs, rhs) >= 0; }
-#endif
 
 // QStringView <> QChar
 inline bool operator==(QStringView lhs, QChar rhs) noexcept { return lhs == QStringView(&rhs, 1); }
diff --git a/src/corelib/text/qutf8stringview.h b/src/corelib/text/qutf8stringview.h
index ac42a3d73f..98357ae5a9 100644
--- a/src/corelib/text/qutf8stringview.h
+++ b/src/corelib/text/qutf8stringview.h
@@ -304,7 +304,30 @@ public:
     constexpr int length() const /* not nothrow! */
     { return Q_ASSERT(int(size()) == size()), int(size()); }
 #endif
+
 private:
+    [[nodiscard]] static inline int compare(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs,
+                                            Qt::CaseSensitivity cs = Qt::CaseSensitive) noexcept;
+
+    [[nodiscard]] friend inline bool operator==(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs) noexcept
+    { return QBasicUtf8StringView::compare(lhs, rhs) == 0; }
+    [[nodiscard]] friend inline bool operator!=(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs) noexcept
+    { return !operator==(lhs, rhs); }
+
+#ifdef __cpp_impl_three_way_comparison
+    [[nodiscard]] friend inline auto operator<=>(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs) noexcept
+    { return QBasicUtf8StringView::compare(lhs, rhs) <=> 0; }
+#else
+    [[nodiscard]] friend inline bool operator<=(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs) noexcept
+    { return QBasicUtf8StringView::compare(lhs, rhs) <= 0; }
+    [[nodiscard]] friend inline bool operator>=(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs) noexcept
+    { return QBasicUtf8StringView::compare(lhs, rhs) >= 0; }
+    [[nodiscard]] friend inline bool operator<(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs) noexcept
+    { return QBasicUtf8StringView::compare(lhs, rhs) < 0; }
+    [[nodiscard]] friend inline bool operator>(QBasicUtf8StringView lhs, QBasicUtf8StringView rhs) noexcept
+    { return QBasicUtf8StringView::compare(lhs, rhs) > 0; }
+#endif
+
     Q_ALWAYS_INLINE constexpr void verify(qsizetype pos, qsizetype n = 0) const
     {
         Q_ASSERT(pos >= 0);