QSqlRecord: add missing C++11 move SMFs

[ChangeLog][QtSql][QSqlRecord] Added move constructor, -assignment
operator, and swap().

Task-number: QTBUG-109938
Change-Id: I54f2666defbf56f5ba2faea6358722ebd7cac157
Reviewed-by: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

src/sql/kernel/qsqlrecord.cpp

@@ -88,6 +88,37 @@ QSqlRecord::QSqlRecord(const QSqlRecord& other)
     d->ref.ref();
 }
 
+/*!
+    \fn QSqlRecord::QSqlRecord(QSqlRecord &&other)
+    \since 6.6
+
+    Move-constructs a new QSqlRecord from \a other.
+
+    \note The moved-from object \a other is placed in a partially-formed state,
+    in which the only valid operations are destruction and assignment of a new
+    value.
+*/
+
+/*!
+    \fn QSqlRecord &QSqlRecord::operator=(QSqlRecord &&other)
+    \since 6.6
+
+    Move-assigns \a other to this QSqlRecord instance.
+
+    \note The moved-from object \a other is placed in a partially-formed state,
+    in which the only valid operations are destruction and assignment of a new
+    value.
+*/
+
+/*!
+    \fn void QSqlRecord::swap(QSqlRecord &other)
+    \since 6.6
+
+    Swaps SQL record \a other with this SQL record. This operation is very fast
+    and never fails.
+*/
+
+
 /*!
     Sets the record equal to \a other.
 
@@ -97,7 +128,7 @@ QSqlRecord::QSqlRecord(const QSqlRecord& other)
 
 QSqlRecord& QSqlRecord::operator=(const QSqlRecord& other)
 {
-    qAtomicAssign(d, other.d);
+    QSqlRecord(other).swap(*this);
     return *this;
 }
 
@@ -107,7 +138,7 @@ QSqlRecord& QSqlRecord::operator=(const QSqlRecord& other)
 
 QSqlRecord::~QSqlRecord()
 {
-    if (!d->ref.deref())
+    if (d && !d->ref.deref())
         delete d;
 }
 

src/sql/kernel/qsqlrecord.h

@@ -19,9 +19,14 @@ class Q_SQL_EXPORT QSqlRecord
 public:
     QSqlRecord();
     QSqlRecord(const QSqlRecord& other);
+    QSqlRecord(QSqlRecord &&other) noexcept
+        : d{std::exchange(other.d, nullptr)} {}
     QSqlRecord& operator=(const QSqlRecord& other);
+    QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QSqlRecord)
     ~QSqlRecord();
 
+    void swap(QSqlRecord &other) noexcept { qt_ptr_swap(d, other.d); }
+
     bool operator==(const QSqlRecord &other) const;
     inline bool operator!=(const QSqlRecord &other) const { return !operator==(other); }
 

tests/auto/sql/kernel/qsqlrecord/tst_qsqlrecord.cpp

@@ -40,6 +40,7 @@ private slots:
     void clearValues();
     void clear();
     void append();
+    void moveSemantics();
 
 private:
     std::unique_ptr<QSqlRecord> rec;
@@ -449,5 +450,24 @@ void tst_QSqlRecord::value()
     QCOMPARE(rec2.value("string").toString(), QLatin1String("Harry"));
 }
 
+void tst_QSqlRecord::moveSemantics()
+{
+    QSqlRecord rec, empty;
+    rec.append(QSqlField("string", QMetaType(QMetaType::QString)));
+    rec.setValue("string", "Harry");
+    auto moved = std::move(rec);
+    // `rec` is not partially-formed
+
+    // moving transfers state:
+    QCOMPARE(moved.value("string").toString(), QLatin1String("Harry"));
+
+    // moved-from objects can be assigned-to:
+    rec = empty;
+    QVERIFY(rec.value("string").isNull());
+
+    // moved-from object can be destroyed:
+    moved = std::move(rec);
+}
+
 QTEST_MAIN(tst_QSqlRecord)
 #include "tst_qsqlrecord.moc"