QVariant: replace v_construct with a Private template constructor

It's effectively the same and no one is using v_construct().

Change-Id: I3859764fed084846bcb0fffd1704470801c9e6e7
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

3 files changed, 61 insertions, 133 deletions

diff --git a/src/corelib/kernel/qvariant.cpp b/src/corelib/kernel/qvariant.cpp
index 5f0e759cf5..7310fd9be2 100644
--- a/src/corelib/kernel/qvariant.cpp
+++ b/src/corelib/kernel/qvariant.cpp
@@ -298,6 +298,22 @@ static QVariant::Private clonePrivate(const QVariant::Private &other)
 
 } // anonymous used to hide QVariant handlers
 
+template <typename T> inline
+QVariant::Private::Private(std::piecewise_construct_t, const T &t)
+    : is_shared(!CanUseInternalSpace<T>), is_null(std::is_same_v<T, std::nullptr_t>)
+{
+    const QtPrivate::QMetaTypeInterface *iface = QtPrivate::qMetaTypeInterfaceForType<T>();
+    Q_ASSERT((quintptr(iface) & 0x3) == 0);
+    packedType = quintptr(iface) >> 2;
+
+    if constexpr (CanUseInternalSpace<T>) {
+        new (data.data) T(t);
+    } else {
+        data.shared = QVariant::PrivateShared::create(QtPrivate::qMetaTypeInterfaceForType<T>());
+        new (data.shared->data()) T(t);
+    }
+}
+
 /*!
     \class QVariant
     \inmodule QtCore
@@ -818,133 +834,60 @@ QVariant::QVariant(QMetaType type, const void *copy) : d(type)
         d = {};
 }
 
-QVariant::QVariant(int val)
-    : d(QMetaType::fromType<int>())
-{ d.set(val); }
-QVariant::QVariant(uint val)
-    : d(QMetaType::fromType<uint>())
-{ d.set(val); }
-QVariant::QVariant(qlonglong val)
-    : d(QMetaType::fromType<qlonglong>())
-{ d.set(val); }
-QVariant::QVariant(qulonglong val)
-    : d(QMetaType::fromType<qulonglong>())
-{ d.set(val); }
-QVariant::QVariant(bool val)
-    : d(QMetaType::fromType<bool>())
-{ d.set(val); }
-QVariant::QVariant(double val)
-    : d(QMetaType::fromType<double>())
-{ d.set(val); }
-QVariant::QVariant(float val)
-    : d(QMetaType::fromType<float>())
-{ d.set(val); }
-
-QVariant::QVariant(const QByteArray &val)
-    : d(QMetaType::fromType<QByteArray>())
-{ v_construct<QByteArray>(&d, val); }
-QVariant::QVariant(const QBitArray &val)
-    : d(QMetaType::fromType<QBitArray>())
-{ v_construct<QBitArray>(&d, val);  }
-QVariant::QVariant(const QString &val)
-    : d(QMetaType::fromType<QString>())
-{ v_construct<QString>(&d, val);  }
-QVariant::QVariant(QChar val)
-    : d(QMetaType::fromType<QChar>())
-{ v_construct<QChar>(&d, val);  }
-QVariant::QVariant(QLatin1StringView val)
-    : d(QMetaType::fromType<QString>())
-{ v_construct<QString>(&d, val); }
-QVariant::QVariant(const QStringList &val)
-    : d(QMetaType::fromType<QStringList>())
-{ v_construct<QStringList>(&d, val); }
-
-QVariant::QVariant(QDate val)
-    : d(QMetaType::fromType<QDate>())
-{ v_construct<QDate>(&d, val); }
-QVariant::QVariant(QTime val)
-    : d(QMetaType::fromType<QTime>())
-{ v_construct<QTime>(&d, val); }
-QVariant::QVariant(const QDateTime &val)
-    : d(QMetaType::fromType<QDateTime>())
-{ v_construct<QDateTime>(&d, val); }
+QVariant::QVariant(int val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(uint val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(qlonglong val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(qulonglong val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(bool val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(double val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(float val) : d(std::piecewise_construct_t{}, val) {}
+
+QVariant::QVariant(const QByteArray &val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(const QBitArray &val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(const QString &val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(QChar val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(const QStringList &val) : d(std::piecewise_construct_t{}, val) {}
+
+QVariant::QVariant(QDate val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(QTime val) : d(std::piecewise_construct_t{}, val) {}
+QVariant::QVariant(const QDateTime &val) : d(std::piecewise_construct_t{}, val) {}
+
+QVariant::QVariant(const QList<QVariant> &list) : d(std::piecewise_construct_t{}, list) {}
+QVariant::QVariant(const QMap<QString, QVariant> &map) : d(std::piecewise_construct_t{}, map) {}
+QVariant::QVariant(const QHash<QString, QVariant> &hash) : d(std::piecewise_construct_t{}, hash) {}
+
+QVariant::QVariant(QLatin1StringView val) : QVariant(QString(val)) {}
+
 #if QT_CONFIG(easingcurve)
-QVariant::QVariant(const QEasingCurve &val)
-    : d(QMetaType::fromType<QEasingCurve>())
-{ v_construct<QEasingCurve>(&d, val); }
+QVariant::QVariant(const QEasingCurve &val) : d(std::piecewise_construct_t{}, val) {}
 #endif
-QVariant::QVariant(const QList<QVariant> &list)
-    : d(QMetaType::fromType<QList<QVariant>>())
-{ v_construct<QVariantList>(&d, list); }
-QVariant::QVariant(const QMap<QString, QVariant> &map)
-    : d(QMetaType::fromType<QMap<QString, QVariant>>())
-{ v_construct<QVariantMap>(&d, map); }
-QVariant::QVariant(const QHash<QString, QVariant> &hash)
-    : d(QMetaType::fromType<QHash<QString, QVariant>>())
-{ v_construct<QVariantHash>(&d, hash); }
 #ifndef QT_NO_GEOM_VARIANT
-QVariant::QVariant(const QPoint &pt)
-    : d(QMetaType::fromType<QPoint>())
-{ v_construct<QPoint>(&d, pt); }
-QVariant::QVariant(const QPointF &pt)
-    : d(QMetaType::fromType<QPointF>())
-{ v_construct<QPointF>(&d, pt); }
-QVariant::QVariant(const QRectF &r)
-    : d(QMetaType::fromType<QRectF>())
-{ v_construct<QRectF>(&d, r); }
-QVariant::QVariant(const QLineF &l)
-    : d(QMetaType::fromType<QLineF>())
-{ v_construct<QLineF>(&d, l); }
-QVariant::QVariant(const QLine &l)
-    : d(QMetaType::fromType<QLine>())
-{ v_construct<QLine>(&d, l); }
-QVariant::QVariant(const QRect &r)
-    : d(QMetaType::fromType<QRect>())
-{ v_construct<QRect>(&d, r); }
-QVariant::QVariant(const QSize &s)
-    : d(QMetaType::fromType<QSize>())
-{ v_construct<QSize>(&d, s); }
-QVariant::QVariant(const QSizeF &s)
-    : d(QMetaType::fromType<QSizeF>())
-{ v_construct<QSizeF>(&d, s); }
+QVariant::QVariant(const QPoint &pt) : d(std::piecewise_construct_t{}, pt) {}
+QVariant::QVariant(const QPointF &pt) : d(std::piecewise_construct_t{}, pt) {}
+QVariant::QVariant(const QRect &r) : d(std::piecewise_construct_t{}, r) {}
+QVariant::QVariant(const QRectF &r) : d(std::piecewise_construct_t{}, r) {}
+QVariant::QVariant(const QLine &l) : d(std::piecewise_construct_t{}, l) {}
+QVariant::QVariant(const QLineF &l) : d(std::piecewise_construct_t{}, l) {}
+QVariant::QVariant(const QSize &s) : d(std::piecewise_construct_t{}, s) {}
+QVariant::QVariant(const QSizeF &s) : d(std::piecewise_construct_t{}, s) {}
 #endif
 #ifndef QT_BOOTSTRAPPED
-QVariant::QVariant(const QUrl &u)
-    : d(QMetaType::fromType<QUrl>())
-{ v_construct<QUrl>(&d, u); }
+QVariant::QVariant(const QUrl &u) : d(std::piecewise_construct_t{}, u) {}
 #endif
-QVariant::QVariant(const QLocale &l)
-    : d(QMetaType::fromType<QLocale>())
-{ v_construct<QLocale>(&d, l); }
+QVariant::QVariant(const QLocale &l) : d(std::piecewise_construct_t{}, l) {}
 #if QT_CONFIG(regularexpression)
-QVariant::QVariant(const QRegularExpression &re)
-    : d(QMetaType::fromType<QRegularExpression>())
-{ v_construct<QRegularExpression>(&d, re); }
+QVariant::QVariant(const QRegularExpression &re) : d(std::piecewise_construct_t{}, re) {}
 #endif // QT_CONFIG(regularexpression)
-QVariant::QVariant(const QUuid &uuid)
-    : d(QMetaType::fromType<QUuid>())
-{ v_construct<QUuid>(&d, uuid); }
+QVariant::QVariant(const QUuid &uuid) : d(std::piecewise_construct_t{}, uuid) {}
 #ifndef QT_BOOTSTRAPPED
-QVariant::QVariant(const QJsonValue &jsonValue)
-    : d(QMetaType::fromType<QJsonValue>())
-{ v_construct<QJsonValue>(&d, jsonValue); }
-QVariant::QVariant(const QJsonObject &jsonObject)
-    : d(QMetaType::fromType<QJsonObject>())
-{ v_construct<QJsonObject>(&d, jsonObject); }
-QVariant::QVariant(const QJsonArray &jsonArray)
-    : d(QMetaType::fromType<QJsonArray>())
-{ v_construct<QJsonArray>(&d, jsonArray); }
-QVariant::QVariant(const QJsonDocument &jsonDocument)
-    : d(QMetaType::fromType<QJsonDocument>())
-{ v_construct<QJsonDocument>(&d, jsonDocument); }
+QVariant::QVariant(const QJsonValue &jsonValue) : d(std::piecewise_construct_t{}, jsonValue) {}
+QVariant::QVariant(const QJsonObject &jsonObject) : d(std::piecewise_construct_t{}, jsonObject) {}
+QVariant::QVariant(const QJsonArray &jsonArray) : d(std::piecewise_construct_t{}, jsonArray) {}
+QVariant::QVariant(const QJsonDocument &jsonDocument) : d(std::piecewise_construct_t{}, jsonDocument) {}
 #endif // QT_BOOTSTRAPPED
 #if QT_CONFIG(itemmodel)
-QVariant::QVariant(const QModelIndex &modelIndex)
-    : d(QMetaType::fromType<QModelIndex>())
-{ v_construct<QModelIndex>(&d, modelIndex); }
-QVariant::QVariant(const QPersistentModelIndex &modelIndex)
-    : d(QMetaType::fromType<QPersistentModelIndex>())
-{ v_construct<QPersistentModelIndex>(&d, modelIndex); }
+QVariant::QVariant(const QModelIndex &modelIndex) : d(std::piecewise_construct_t{}, modelIndex) {}
+QVariant::QVariant(const QPersistentModelIndex &modelIndex) : d(std::piecewise_construct_t{}, modelIndex) {}
 #endif
 
 /*! \fn QVariant::Type QVariant::type() const
diff --git a/src/corelib/kernel/qvariant.h b/src/corelib/kernel/qvariant.h
index dc73f46af5..aca2db2cbe 100644
--- a/src/corelib/kernel/qvariant.h
+++ b/src/corelib/kernel/qvariant.h
@@ -445,7 +445,8 @@ public:
         quintptr is_null : 1;
         quintptr packedType : sizeof(QMetaType) * 8 - 2;
 
-        Private() noexcept : is_shared(false), is_null(true), packedType(0) {}
+        constexpr Private() noexcept : is_shared(false), is_null(true), packedType(0) {}
+        template <typename T> explicit Private(std::piecewise_construct_t, const T &t);
         explicit Private(QMetaType type) noexcept : is_shared(false), is_null(false)
         {
             quintptr mt = quintptr(type.d_ptr);
@@ -464,9 +465,6 @@ public:
         template<typename T>
         const T &get() const
         { return *static_cast<const T *>(CanUseInternalSpace<T> ? &data.data : data.shared->data()); }
-        template<typename T>
-        void set(const T &t)
-        { *static_cast<T *>(CanUseInternalSpace<T> ? &data.data : data.shared->data()) = t; }
 
         inline const QtPrivate::QMetaTypeInterface* typeInterface() const
         {
diff --git a/src/corelib/kernel/qvariant_p.h b/src/corelib/kernel/qvariant_p.h
index 593adfd0e9..40fde48a1c 100644
--- a/src/corelib/kernel/qvariant_p.h
+++ b/src/corelib/kernel/qvariant_p.h
@@ -22,19 +22,6 @@
 
 QT_BEGIN_NAMESPACE
 
-template <class T>
-inline void v_construct(QVariant::Private *x, const T &t)
-{
-    if constexpr (QVariant::Private::CanUseInternalSpace<T>) {
-        new (&x->data) T(t);
-        x->is_shared = false;
-    } else {
-        x->data.shared = QVariant::PrivateShared::create(QtPrivate::qMetaTypeInterfaceForType<T>());
-        new (x->data.shared->data()) T(t);
-        x->is_shared = true;
-    }
-}
-
 QT_END_NAMESPACE
 
 #endif // QVARIANT_P_H