QJsonObject iterators: use new comparison helper macros

New comparison macros are used for following classes:
- QJsonObject::iterator
- QJsonObject::const_iterator

Replace public operators operator==(), operator!=(), operator!<(), etc
of classes to friend methods comparesEqual(), compareThreeWay();

Use *_helper methods to have an access to protected members of
QCborValueConstRef class from friend functions.

Task-number: QTBUG-120300
Change-Id: I308e2c0a549ff186c1d6339b38e989b80dc388a3
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 160 insertions, 57 deletions

diff --git a/src/corelib/serialization/qjsonobject.cpp b/src/corelib/serialization/qjsonobject.cpp
index 652f1b4da5..2f61de0824 100644
--- a/src/corelib/serialization/qjsonobject.cpp
+++ b/src/corelib/serialization/qjsonobject.cpp
@@ -840,6 +840,10 @@ QJsonObject::const_iterator QJsonObject::constFindImpl(T key) const
 
     \brief The QJsonObject::iterator class provides an STL-style non-const iterator for QJsonObject.
 
+    \compares strong
+    \compareswith strong QJsonObject::const_iterator
+    \endcompareswith
+
     QJsonObject::iterator allows you to iterate over a QJsonObject
     and to modify the value (but not the key) stored under
     a particular key. If you want to iterate over a const QJsonObject, you
@@ -973,55 +977,55 @@ QJsonObject::const_iterator QJsonObject::constFindImpl(T key) const
 */
 
 /*!
-    \fn bool QJsonObject::iterator::operator==(const iterator &other) const
-    \fn bool QJsonObject::iterator::operator==(const const_iterator &other) const
+    \fn bool QJsonObject::iterator::operator==(const iterator &lhs, const iterator &rhs)
+    \fn bool QJsonObject::iterator::operator==(const iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if \a other points to the same item as this
+    Returns \c true if \a lhs points to the same item as \a rhs
     iterator; otherwise returns \c false.
 
     \sa operator!=()
 */
 
 /*!
-    \fn bool QJsonObject::iterator::operator!=(const iterator &other) const
-    \fn bool QJsonObject::iterator::operator!=(const const_iterator &other) const
+    \fn bool QJsonObject::iterator::operator!=(const iterator &lhs, const iterator &rhs)
+    \fn bool QJsonObject::iterator::operator!=(const iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if \a other points to a different item than this
+    Returns \c true if \a lhs points to a different item than \a rhs
     iterator; otherwise returns \c false.
 
     \sa operator==()
 */
 
 /*!
-    \fn bool QJsonObject::iterator::operator<(const iterator& other) const
-    \fn bool QJsonObject::iterator::operator<(const const_iterator& other) const
+    \fn bool QJsonObject::iterator::operator<(const iterator &lhs, const iterator &rhs)
+    \fn bool QJsonObject::iterator::operator<(const iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if the item pointed to by this iterator is less than
-    the item pointed to by the \a other iterator.
+    Returns \c true if the item pointed to by \a lhs iterator is less than
+    the item pointed to by the \a rhs iterator.
 */
 
 /*!
-    \fn bool QJsonObject::iterator::operator<=(const iterator& other) const
-    \fn bool QJsonObject::iterator::operator<=(const const_iterator& other) const
+    \fn bool QJsonObject::iterator::operator<=(const iterator &lhs, const iterator &rhs)
+    \fn bool QJsonObject::iterator::operator<=(const iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if the item pointed to by this iterator is less than
-    or equal to the item pointed to by the \a other iterator.
+    Returns \c true if the item pointed to by \a lhs iterator is less than
+    or equal to the item pointed to by the \a rhs iterator.
 */
 
 /*!
-    \fn bool QJsonObject::iterator::operator>(const iterator& other) const
-    \fn bool QJsonObject::iterator::operator>(const const_iterator& other) const
+    \fn bool QJsonObject::iterator::operator>(const iterator &lhs, const iterator &rhs)
+    \fn bool QJsonObject::iterator::operator>(const iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if the item pointed to by this iterator is greater
-    than the item pointed to by the \a other iterator.
+    Returns \c true if the item pointed to by \a lhs iterator is greater
+    than the item pointed to by the \a rhs iterator.
 */
 
 /*!
-    \fn bool QJsonObject::iterator::operator>=(const iterator& other) const
-    \fn bool QJsonObject::iterator::operator>=(const const_iterator& other) const
+    \fn bool QJsonObject::iterator::operator>=(const iterator &lhs, const iterator &rhs)
+    \fn bool QJsonObject::iterator::operator>=(const iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if the item pointed to by this iterator is greater
-    than or equal to the item pointed to by the \a other iterator.
+    Returns \c true if the item pointed to by \a lhs iterator is greater
+    than or equal to the item pointed to by the \a rhs iterator.
 */
 
 /*! \fn QJsonObject::iterator QJsonObject::iterator::operator++()
@@ -1110,6 +1114,10 @@ QJsonObject::const_iterator QJsonObject::constFindImpl(T key) const
     \since 5.0
     \brief The QJsonObject::const_iterator class provides an STL-style const iterator for QJsonObject.
 
+    \compares strong
+    \compareswith strong QJsonObject::iterator
+    \endcompareswith
+
     QJsonObject::const_iterator allows you to iterate over a QJsonObject.
     If you want to modify the QJsonObject as you iterate
     over it, you must use QJsonObject::iterator instead. It is generally
@@ -1218,50 +1226,48 @@ QJsonObject::const_iterator QJsonObject::constFindImpl(T key) const
 */
 
 
-/*! \fn bool QJsonObject::const_iterator::operator==(const const_iterator &other) const
-    \fn bool QJsonObject::const_iterator::operator==(const iterator &other) const
+/*! \fn bool QJsonObject::const_iterator::operator==(const const_iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if \a other points to the same item as this
+    Returns \c true if \a lhs points to the same item as \a rhs
     iterator; otherwise returns \c false.
 
     \sa operator!=()
 */
 
-/*! \fn bool QJsonObject::const_iterator::operator!=(const const_iterator &other) const
-    \fn bool QJsonObject::const_iterator::operator!=(const iterator &other) const
+/*! \fn bool QJsonObject::const_iterator::operator!=(const const_iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if \a other points to a different item than this
+    Returns \c true if \a lhs points to a different item than \a rhs
     iterator; otherwise returns \c false.
 
     \sa operator==()
 */
 
 /*!
-    \fn bool QJsonObject::const_iterator::operator<(const const_iterator& other) const
+    \fn bool QJsonObject::const_iterator::operator<(const const_iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if the item pointed to by this iterator is less than
-    the item pointed to by the \a other iterator.
+    Returns \c true if the item pointed to by \a lhs iterator is less than
+    the item pointed to by the \a rhs iterator.
 */
 
 /*!
-    \fn bool QJsonObject::const_iterator::operator<=(const const_iterator& other) const
+    \fn bool QJsonObject::const_iterator::operator<=(const const_iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if the item pointed to by this iterator is less than
-    or equal to the item pointed to by the \a other iterator.
+    Returns \c true if the item pointed to by \a lhs iterator is less than
+    or equal to the item pointed to by the \a rhs iterator.
 */
 
 /*!
-    \fn bool QJsonObject::const_iterator::operator>(const const_iterator& other) const
+    \fn bool QJsonObject::const_iterator::operator>(const const_iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if the item pointed to by this iterator is greater
-    than the item pointed to by the \a other iterator.
+    Returns \c true if the item pointed to by \a lhs iterator is greater
+    than the item pointed to by the \a rhs iterator.
 */
 
 /*!
-    \fn bool QJsonObject::const_iterator::operator>=(const const_iterator& other) const
+    \fn bool QJsonObject::const_iterator::operator>=(const const_iterator &lhs, const const_iterator &rhs)
 
-    Returns \c true if the item pointed to by this iterator is greater
-    than or equal to the item pointed to by the \a other iterator.
+    Returns \c true if the item pointed to by \a lhs iterator is greater
+    than or equal to the item pointed to by the \a rhs iterator.
 */
 
 /*! \fn QJsonObject::const_iterator QJsonObject::const_iterator::operator++()
diff --git a/src/corelib/serialization/qjsonobject.h b/src/corelib/serialization/qjsonobject.h
index 009f6c920f..4cdbf4511d 100644
--- a/src/corelib/serialization/qjsonobject.h
+++ b/src/corelib/serialization/qjsonobject.h
@@ -107,17 +107,17 @@ public:
         inline const QJsonValueConstRef *operator->() const { return &item; }
         inline QJsonValueRef *operator->() { return &item; }
         inline QJsonValueRef operator[](qsizetype j) const { return *(*this + j); }
-
+#if QT_CORE_REMOVED_SINCE(6, 8)
         inline bool operator==(const iterator &other) const
         { return item.d == other.item.d && item.index == other.item.index; }
-        inline bool operator!=(const iterator &other) const { return !(*this == other); }
+        inline bool operator!=(const iterator &other) const { return !operator==(other); }
         bool operator<(const iterator& other) const
         { Q_ASSERT(item.d == other.item.d); return item.index < other.item.index; }
         bool operator<=(const iterator& other) const
         { Q_ASSERT(item.d == other.item.d); return item.index <= other.item.index; }
-        bool operator>(const iterator& other) const { return !(*this <= other); }
-        bool operator>=(const iterator& other) const { return !(*this < other); }
-
+        bool operator>(const iterator& other) const { return !operator<=(other); }
+        bool operator>=(const iterator& other) const { return !operator<(other); }
+#endif
         inline iterator &operator++() { ++item.index; return *this; }
         inline iterator operator++(int) { iterator r = *this; ++item.index; return r; }
         inline iterator &operator--() { --item.index; return *this; }
@@ -129,15 +129,63 @@ public:
         qsizetype operator-(iterator j) const { return item.index - j.item.index; }
 
     public:
+#if QT_CORE_REMOVED_SINCE(6, 8)
         inline bool operator==(const const_iterator &other) const
         { return item.d == other.item.d && item.index == other.item.index; }
-        inline bool operator!=(const const_iterator &other) const { return !(*this == other); }
+        inline bool operator!=(const const_iterator &other) const { return !operator==(other); }
         bool operator<(const const_iterator& other) const
         { Q_ASSERT(item.d == other.item.d); return item.index < other.item.index; }
         bool operator<=(const const_iterator& other) const
         { Q_ASSERT(item.d == other.item.d); return item.index <= other.item.index; }
-        bool operator>(const const_iterator& other) const { return !(*this <= other); }
-        bool operator>=(const const_iterator& other) const { return !(*this < other); }
+        bool operator>(const const_iterator& other) const { return operator<=(other); }
+        bool operator>=(const const_iterator& other) const { return operator<(other); }
+#endif
+    private:
+        // Helper functions
+        static bool comparesEqual_helper(const iterator &lhs, const iterator &rhs) noexcept
+        {
+            return lhs.item.d == rhs.item.d && lhs.item.index == rhs.item.index;
+        }
+        static bool comparesEqual_helper(const iterator &lhs, const const_iterator &rhs) noexcept
+        {
+            return lhs.item.d == rhs.item.d && lhs.item.index == rhs.item.index;
+        }
+
+        static Qt::strong_ordering compareThreeWay_helper(const iterator &lhs,
+                                                          const iterator &rhs) noexcept
+        {
+            Q_ASSERT(lhs.item.d == rhs.item.d);
+            return Qt::compareThreeWay(lhs.item.index, rhs.item.index);
+        }
+        static Qt::strong_ordering compareThreeWay_helper(const iterator &lhs,
+                                                          const const_iterator &rhs) noexcept
+        {
+            Q_ASSERT(lhs.item.d == rhs.item.d);
+            return Qt::compareThreeWay(lhs.item.index, rhs.item.index);
+        }
+
+        // Compare friends
+        friend bool comparesEqual(const iterator &lhs, const iterator &rhs) noexcept
+        {
+            return comparesEqual_helper(lhs, rhs);
+        }
+        friend Qt::strong_ordering compareThreeWay(const iterator &lhs,
+                                                   const iterator &rhs) noexcept
+        {
+            return compareThreeWay_helper(lhs, rhs);
+        }
+        Q_DECLARE_STRONGLY_ORDERED(iterator)
+
+        friend bool comparesEqual(const iterator &lhs, const const_iterator &rhs) noexcept
+        {
+            return comparesEqual_helper(lhs, rhs);
+        }
+        friend Qt::strong_ordering compareThreeWay(const iterator &lhs,
+                                                   const const_iterator &rhs) noexcept
+        {
+            return compareThreeWay_helper(lhs, rhs);
+        }
+        Q_DECLARE_STRONGLY_ORDERED(iterator, const_iterator)
     };
     friend class iterator;
 
@@ -171,17 +219,17 @@ public:
         inline const QJsonValueConstRef operator*() const { return item; }
         inline const QJsonValueConstRef *operator->() const { return &item; }
         inline QJsonValueConstRef operator[](qsizetype j) const { return *(*this + j); }
-
+#if QT_CORE_REMOVED_SINCE(6, 8)
         inline bool operator==(const const_iterator &other) const
         { return item.d == other.item.d && item.index == other.item.index; }
-        inline bool operator!=(const const_iterator &other) const { return !(*this == other); }
+        inline bool operator!=(const const_iterator &other) const { return !operator==(other); }
         bool operator<(const const_iterator& other) const
         { Q_ASSERT(item.d == other.item.d); return item.index < other.item.index; }
         bool operator<=(const const_iterator& other) const
         { Q_ASSERT(item.d == other.item.d); return item.index <= other.item.index; }
-        bool operator>(const const_iterator& other) const { return !(*this <= other); }
-        bool operator>=(const const_iterator& other) const { return !(*this < other); }
-
+        bool operator>(const const_iterator& other) const { return !operator<=(other); }
+        bool operator>=(const const_iterator& other) const { return !operator<(other); }
+#endif
         inline const_iterator &operator++() { ++item.index; return *this; }
         inline const_iterator operator++(int) { const_iterator r = *this; ++item.index; return r; }
         inline const_iterator &operator--() { --item.index; return *this; }
@@ -191,16 +239,43 @@ public:
         inline const_iterator &operator+=(qsizetype j) { item.index += quint64(j); return *this; }
         inline const_iterator &operator-=(qsizetype j) { item.index -= quint64(j); return *this; }
         qsizetype operator-(const_iterator j) const { return item.index - j.item.index; }
-
+#if QT_CORE_REMOVED_SINCE(6, 8)
         inline bool operator==(const iterator &other) const
         { return item.d == other.item.d && item.index == other.item.index; }
-        inline bool operator!=(const iterator &other) const { return !(*this == other); }
+        inline bool operator!=(const iterator &other) const { return !operator==(other); }
         bool operator<(const iterator& other) const
         { Q_ASSERT(item.d == other.item.d); return item.index < other.item.index; }
         bool operator<=(const iterator& other) const
         { Q_ASSERT(item.d == other.item.d); return item.index <= other.item.index; }
-        bool operator>(const iterator& other) const { return !(*this <= other); }
-        bool operator>=(const iterator& other) const { return !(*this < other); }
+        bool operator>(const iterator& other) const { return !operator<=(other); }
+        bool operator>=(const iterator& other) const { return !operator<(other); }
+#endif
+
+    private:
+        // Helper functions
+        static bool comparesEqual_helper(const const_iterator &lhs,
+                                         const const_iterator &rhs) noexcept
+        {
+            return lhs.item.d == rhs.item.d && lhs.item.index == rhs.item.index;
+        }
+        static Qt::strong_ordering compareThreeWay_helper(const const_iterator &lhs,
+                                                          const const_iterator &rhs) noexcept
+        {
+            Q_ASSERT(lhs.item.d == rhs.item.d);
+            return Qt::compareThreeWay(lhs.item.index, rhs.item.index);
+        }
+
+        // Compare friends
+        friend bool comparesEqual(const const_iterator &lhs, const const_iterator &rhs) noexcept
+        {
+            return comparesEqual_helper(lhs, rhs);
+        }
+        friend Qt::strong_ordering compareThreeWay(const const_iterator &lhs,
+                                                   const const_iterator &rhs) noexcept
+        {
+            return compareThreeWay_helper(lhs, rhs);
+        }
+        Q_DECLARE_STRONGLY_ORDERED(const_iterator)
     };
     friend class const_iterator;
 
diff --git a/tests/auto/corelib/serialization/json/tst_qtjson.cpp b/tests/auto/corelib/serialization/json/tst_qtjson.cpp
index 4b6468f42f..54ef9be4f2 100644
--- a/tests/auto/corelib/serialization/json/tst_qtjson.cpp
+++ b/tests/auto/corelib/serialization/json/tst_qtjson.cpp
@@ -182,6 +182,8 @@ void tst_QtJson::compareCompiles()
                                                     QJsonArray::const_iterator>();
     QTestPrivate::testEqualityOperatorsCompile<QJsonDocument>();
     QTestPrivate::testEqualityOperatorsCompile<QJsonObject>();
+    QTestPrivate::testEqualityOperatorsCompile<QJsonObject::iterator>();
+    QTestPrivate::testEqualityOperatorsCompile<QJsonObject::const_iterator>();
     QTestPrivate::testEqualityOperatorsCompile<QJsonValue>();
     QTestPrivate::testEqualityOperatorsCompile<QJsonValueConstRef>();
     QTestPrivate::testEqualityOperatorsCompile<QJsonValueRef>();
@@ -192,6 +194,8 @@ void tst_QtJson::compareCompiles()
     QTestPrivate::testEqualityOperatorsCompile<QJsonValueConstRef, QJsonValue>();
     QTestPrivate::testEqualityOperatorsCompile<QJsonValueRef, QJsonValue>();
     QTestPrivate::testEqualityOperatorsCompile<QJsonValueRef, QJsonValueConstRef>();
+    QTestPrivate::testEqualityOperatorsCompile<QJsonObject::iterator,
+                                               QJsonObject::const_iterator>();
 }
 
 void tst_QtJson::testValueSimple()
@@ -1108,6 +1112,7 @@ void tst_QtJson::testObjectIteration()
     for (QJsonObject::iterator it = object.begin(); it != object.end(); ++it) {
         QJsonValue value = it.value();
         QCOMPARE((double)it.key().toInt(), value.toDouble());
+        QT_TEST_EQUALITY_OPS(it, QJsonObject::iterator(), false);
     }
 
     {
@@ -1120,6 +1125,7 @@ void tst_QtJson::testObjectIteration()
         QCOMPARE(object.size(), 10);
         QCOMPARE(object2.size(), 9);
         QVERIFY(next == object2.begin());
+        QT_TEST_EQUALITY_OPS(next, object2.begin(), true);
 
         double d = 1;   // we erased the first item
         for (auto it = object2.constBegin(); it != object2.constEnd(); ++it, d += 1) {
@@ -1178,6 +1184,7 @@ void tst_QtJson::testObjectIteration()
     {
         QJsonObject::Iterator it = object.begin();
         it += 5;
+        QT_TEST_ALL_COMPARISON_OPS(it, object.begin(), Qt::strong_ordering::greater);
         QCOMPARE(QJsonValue(it.value()).toDouble(), 5.);
         it -= 3;
         QCOMPARE(QJsonValue(it.value()).toDouble(), 2.);
@@ -1192,10 +1199,14 @@ void tst_QtJson::testObjectIteration()
         it += 5;
         QCOMPARE(QJsonValue(it.value()).toDouble(), 5.);
         it -= 3;
+        QT_TEST_ALL_COMPARISON_OPS(object.constBegin(), it, Qt::strong_ordering::less);
         QCOMPARE(QJsonValue(it.value()).toDouble(), 2.);
         QJsonObject::ConstIterator it2 = it + 5;
+        QT_TEST_EQUALITY_OPS(it, it2, false);
         QCOMPARE(QJsonValue(it2.value()).toDouble(), 7.);
         it2 = it - 1;
+        QT_TEST_ALL_COMPARISON_OPS(it2, it, Qt::strong_ordering::less);
+        QT_TEST_ALL_COMPARISON_OPS(it2, it - 2, Qt::strong_ordering::greater);
         QCOMPARE(QJsonValue(it2.value()).toDouble(), 1.);
     }
 
@@ -1204,6 +1215,17 @@ void tst_QtJson::testObjectIteration()
         it = object.erase(it);
     QCOMPARE(object.size() , 0);
     QCOMPARE(it, object.end());
+    QT_TEST_ALL_COMPARISON_OPS(it, object.end(), Qt::strong_ordering::equal);
+    QT_TEST_ALL_COMPARISON_OPS(it, object.constEnd(), Qt::strong_ordering::equal);
+    QT_TEST_ALL_COMPARISON_OPS(it, object.begin(),
+                               Qt::strong_ordering::equal); // because object is empty
+    QT_TEST_ALL_COMPARISON_OPS(it, object.constBegin(), Qt::strong_ordering::equal);
+    QT_TEST_ALL_COMPARISON_OPS(QJsonObject::Iterator(),
+                               QJsonObject::Iterator(), Qt::strong_ordering::equal);
+    QT_TEST_ALL_COMPARISON_OPS(QJsonObject::ConstIterator(),
+                               QJsonObject::Iterator(), Qt::strong_ordering::equal);
+    QT_TEST_ALL_COMPARISON_OPS(QJsonObject::ConstIterator(),
+                               QJsonObject::ConstIterator(), Qt::strong_ordering::equal);
 }
 
 void tst_QtJson::testArrayIteration()