QRMA: add move assignment operator to DataReference

Don't copy the new value into the QVariant if we can move it.

Also add move-construction and move-assignment SFM to the DataReference
type itself; they don't save us anything right now, but it clarifies the
semantics.

Amends e22cd01076e795ed853b0536605d3bb205587d78.

Pick-to: 6.11
Change-Id: I6cdba7a03f5e6e59bb9e2f5e44483fea7b1ed1cc
Reviewed-by: Artem Dyomin <[email protected]>

1 files changed, 40 insertions, 18 deletions

diff --git a/src/corelib/itemmodels/qrangemodeladapter.h b/src/corelib/itemmodels/qrangemodeladapter.h
index bd3342e6185..bb57b816fe5 100644
--- a/src/corelib/itemmodels/qrangemodeladapter.h
+++ b/src/corelib/itemmodels/qrangemodeladapter.h
@@ -141,6 +141,7 @@ public:
         }
 
         DataReference(const DataReference &other) = default;
+        DataReference(DataReference &&other) = default;
 
         // reference (not std::reference_wrapper) semantics
         DataReference &operator=(const DataReference &other)
@@ -149,29 +150,23 @@ public:
             return *this;
         }
 
+        DataReference &operator=(DataReference &&other)
+        {
+            *this = other.get();
+            return *this;
+        }
+
         ~DataReference() = default;
 
         DataReference &operator=(const value_type &value)
         {
-            constexpr Qt::ItemDataRole dataRole = Qt::RangeModelAdapterRole;
+            assign(value);
+            return *this;
+        }
 
-            if (m_index.isValid()) {
-                auto model = const_cast<QAbstractItemModel *>(m_index.model());
-                [[maybe_unused]] bool couldWrite = false;
-                if constexpr (std::is_same_v<q20::remove_cvref_t<value_type>, QVariant>)
-                    couldWrite = model->setData(m_index, value, dataRole);
-                else
-                    couldWrite = model->setData(m_index, QVariant::fromValue(value), dataRole);
-#ifndef QT_NO_DEBUG
-                if (!couldWrite) {
-                    qWarning() << "Writing value of type" << QMetaType::fromType<value_type>().name()
-                               << "to role" << dataRole << "at index" << m_index
-                               << "of the model failed";
-                }
-            } else {
-                qCritical("Data reference for invalid index, can't write to model");
-#endif
-            }
+        DataReference &operator=(value_type &&value)
+        {
+            assign(std::move(value));
             return *this;
         }
 
@@ -196,6 +191,33 @@ public:
     private:
         QModelIndex m_index;
 
+        template <typename Value>
+        void assign(Value &&value)
+        {
+            constexpr Qt::ItemDataRole dataRole = Qt::RangeModelAdapterRole;
+
+            if (m_index.isValid()) {
+                auto model = const_cast<QAbstractItemModel *>(m_index.model());
+                [[maybe_unused]] bool couldWrite = false;
+                if constexpr (std::is_same_v<q20::remove_cvref_t<Value>, QVariant>) {
+                    couldWrite = model->setData(m_index, value, dataRole);
+                } else {
+                    couldWrite = model->setData(m_index,
+                                                QVariant::fromValue(std::forward<Value>(value)),
+                                                dataRole);
+                }
+#ifndef QT_NO_DEBUG
+                if (!couldWrite) {
+                    qWarning() << "Writing value of type"
+                               << QMetaType::fromType<q20::remove_cvref_t<Value>>().name()
+                               << "to role" << dataRole << "at index" << m_index << "failed";
+                }
+            } else {
+                qCritical("Data reference for invalid index, can't write to model");
+#endif
+            }
+        }
+
         friend inline bool comparesEqual(const DataReference &lhs, const DataReference &rhs)
         {
             return lhs.m_index == rhs.m_index