Merge "QSqlQuery: make it a move only type"

src/corelib/tools/qhash.cpp

@@ -740,6 +740,7 @@ static uint qt_create_qhash_seed()
 /*
     The QHash seed itself.
 */
+// ### Qt 7: this should use size_t, not int.
 static QBasicAtomicInt qt_qhash_seed = Q_BASIC_ATOMIC_INITIALIZER(-1);
 
 /*!

src/corelib/tools/qhashfunctions.h

@@ -64,6 +64,7 @@ class QByteArray;
 class QString;
 class QLatin1String;
 
+// ### Qt 7: these should use size_t, not int.
 Q_CORE_EXPORT int qGlobalQHashSeed();
 Q_CORE_EXPORT void qSetGlobalQHashSeed(int newSeed);
 

src/sql/kernel/qsqlquery.cpp

@@ -243,12 +243,18 @@ QSqlQuery::QSqlQuery(QSqlResult *result)
 
 QSqlQuery::~QSqlQuery()
 {
-    if (!d->ref.deref())
+    if (d && !d->ref.deref())
         delete d;
 }
 
+#if QT_DEPRECATED_SINCE(6, 2)
 /*!
     Constructs a copy of \a other.
+
+    \obsolete QSqlQuery cannot be meaningfully copied. Prepared
+    statements, bound values and so on will not work correctly, depending
+    on your database driver (for instance, changing the copy will affect
+    the original). Treat QSqlQuery as a move-only type instead.
 */
 
 QSqlQuery::QSqlQuery(const QSqlQuery& other)
@@ -257,6 +263,41 @@ QSqlQuery::QSqlQuery(const QSqlQuery& other)
     d->ref.ref();
 }
 
+/*!
+    Assigns \a other to this object.
+
+    \obsolete QSqlQuery cannot be meaningfully copied. Prepared
+    statements, bound values and so on will not work correctly, depending
+    on your database driver (for instance, changing the copy will affect
+    the original). Treat QSqlQuery as a move-only type instead.
+*/
+
+QSqlQuery& QSqlQuery::operator=(const QSqlQuery& other)
+{
+    qAtomicAssign(d, other.d);
+    return *this;
+}
+#endif
+
+/*!
+    \fn QSqlQuery::QSqlQuery(QSqlQuery &&other) noexcept
+    \since 6.2
+    Move-constructs a QSqlQuery from \a other.
+*/
+
+/*!
+    \fn QSqlQuery &QSqlQuery::operator=(QSqlQuery &&other) noexcept
+    \since 6.2
+    Move-assigns \a other to this object.
+*/
+
+/*!
+    \fn void QSqlQuery::swap(QSqlQuery &other) noexcept
+    \since 6.2
+    Swaps \a other to this object. This operation is very
+    fast and never fails.
+*/
+
 /*!
     \internal
 */
@@ -299,17 +340,6 @@ QSqlQuery::QSqlQuery(const QSqlDatabase &db)
     qInit(this, QString(), db);
 }
 
-
-/*!
-    Assigns \a other to this object.
-*/
-
-QSqlQuery& QSqlQuery::operator=(const QSqlQuery& other)
-{
-    qAtomicAssign(d, other.d);
-    return *this;
-}
-
 /*!
     Returns \c true if the query is not \l{isActive()}{active},
     the query is not positioned on a valid record,

src/sql/kernel/qsqlquery.h

@@ -61,10 +61,29 @@ public:
     explicit QSqlQuery(QSqlResult *r);
     explicit QSqlQuery(const QString& query = QString(), const QSqlDatabase &db = QSqlDatabase());
     explicit QSqlQuery(const QSqlDatabase &db);
-    QSqlQuery(const QSqlQuery& other);
-    QSqlQuery& operator=(const QSqlQuery& other);
+
+#if QT_DEPRECATED_SINCE(6, 2)
+    QT_DEPRECATED_VERSION_X_6_2("QSqlQuery is not meant to be copied. Use move construction instead.")
+    QSqlQuery(const QSqlQuery &other);
+    QT_DEPRECATED_VERSION_X_6_2("QSqlQuery is not meant to be copied. Use move assignment instead.")
+    QSqlQuery& operator=(const QSqlQuery &other);
+#else
+    QSqlQuery(const QSqlQuery &other) = delete;
+    QSqlQuery& operator=(const QSqlQuery &other) = delete;
+#endif
+
+    QSqlQuery(QSqlQuery &&other) noexcept
+        : d(std::exchange(other.d, nullptr))
+    {}
+    QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QSqlQuery)
+
     ~QSqlQuery();
 
+    void swap(QSqlQuery &other) noexcept
+    {
+        qSwap(d, other.d);
+    }
+
     bool isValid() const;
     bool isActive() const;
     bool isNull(int field) const;

src/sql/models/qsqlquerymodel.cpp

@@ -418,6 +418,20 @@ void QSqlQueryModel::queryChange()
     // do nothing
 }
 
+
+/*!
+    \obsolete
+    \overload
+    \since 4.5
+
+    Use the \c{setQuery(QSqlQuery &&query)} overload instead.
+*/
+void QSqlQueryModel::setQuery(const QSqlQuery &query)
+{
+    QT_IGNORE_DEPRECATIONS(QSqlQuery copy = query;)
+    setQuery(std::move(copy));
+}
+
 /*!
     Resets the model and sets the data provider to be the given \a
     query. Note that the query must be active and must not be
@@ -428,9 +442,11 @@ void QSqlQueryModel::queryChange()
 
     \note Calling setQuery() will remove any inserted columns.
 
+    \since 6.2
+
     \sa query(), QSqlQuery::isActive(), QSqlQuery::setForwardOnly(), lastError()
 */
-void QSqlQueryModel::setQuery(const QSqlQuery &query)
+void QSqlQueryModel::setQuery(QSqlQuery &&query)
 {
     Q_D(QSqlQueryModel);
     beginResetModel();
@@ -443,11 +459,11 @@ void QSqlQueryModel::setQuery(const QSqlQuery &query)
 
     d->bottom = QModelIndex();
     d->error = QSqlError();
-    d->query = query;
+    d->query = std::move(query);
     d->rec = newRec;
     d->atEnd = true;
 
-    if (query.isForwardOnly()) {
+    if (d->query.isForwardOnly()) {
         d->error = QSqlError(QLatin1String("Forward-only queries "
                                            "cannot be used in a data model"),
                              QString(), QSqlError::ConnectionError);
@@ -455,13 +471,13 @@ void QSqlQueryModel::setQuery(const QSqlQuery &query)
         return;
     }
 
-    if (!query.isActive()) {
-        d->error = query.lastError();
+    if (!d->query.isActive()) {
+        d->error = d->query.lastError();
         endResetModel();
         return;
     }
 
-    if (query.driver()->hasFeature(QSqlDriver::QuerySize) && d->query.size() > 0) {
+    if (d->query.driver()->hasFeature(QSqlDriver::QuerySize) && d->query.size() > 0) {
         d->bottom = createIndex(d->query.size() - 1, d->rec.count() - 1);
     } else {
         d->bottom = createIndex(-1, d->rec.count() - 1);
@@ -545,11 +561,14 @@ bool QSqlQueryModel::setHeaderData(int section, Qt::Orientation orientation,
 
     \sa setQuery()
 */
+QT_WARNING_PUSH
+QT_WARNING_DISABLE_DEPRECATED
 QSqlQuery QSqlQueryModel::query() const
 {
     Q_D(const QSqlQueryModel);
     return d->query;
 }
+QT_WARNING_POP
 
 /*!
     Returns information about the last error that occurred on the

src/sql/models/qsqlquerymodel.h

@@ -76,7 +76,11 @@ public:
     bool insertColumns(int column, int count, const QModelIndex &parent = QModelIndex()) override;
     bool removeColumns(int column, int count, const QModelIndex &parent = QModelIndex()) override;
 
+#if QT_DEPRECATED_SINCE(6, 2)
+    QT_DEPRECATED_VERSION_X_6_2("QSqlQuery is not meant to be copied. Pass it by move instead.")
     void setQuery(const QSqlQuery &query);
+#endif
+    void setQuery(QSqlQuery &&query);
     void setQuery(const QString &query, const QSqlDatabase &db = QSqlDatabase());
     QSqlQuery query() const;
 

tests/auto/sql/models/qsqlquerymodel/tst_qsqlquerymodel.cpp

@@ -573,7 +573,7 @@ void tst_QSqlQueryModel::setQueryWithNoRowsInResultSet()
     // The query's result set will be empty so no signals should be emitted!
     QSqlQuery query(db);
     QVERIFY_SQL(query, exec("SELECT * FROM " + qTableName("test", __FILE__, db) + " where 0 = 1"));
-    model.setQuery(query);
+    model.setQuery(std::move(query));
     QCOMPARE(modelRowsAboutToBeInsertedSpy.count(), 0);
     QCOMPARE(modelRowsInsertedSpy.count(), 0);
 }