Initial work on gadget support

Changed built-in QtQml value types to use gadgets. This is in preparation for
supporting external gadgets.

This replaces the mostly direct inheritance of the concrete value types with
gadgets and "dynamic" inheritance through QQmlValueType being generic. Over
time as some of the value types may become gadgets, we can remove the ones
here. It's important that these "separate" gadgets have the same memory layout
as the actual types (QPointF, etc.).

Also while QQmlValueType remains practically a singleton, it's not required
anymore to be one. Consequently the JS wrappers for value types keep their own
instance of QQmlValueType. This allows eliminating the qobject_cast in various
places that dealt with the singleton nature. This comes at a cost, making the
JS wrappers slightly heavier. However that is meant to be a temporary situation
and finally the value type wrapper should merely store the meta-object in
addition to the data and the type.

Change-Id: I15071ded0a1e54203f29ec1ecf7a9ab646d1168e
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 47 insertions, 111 deletions

diff --git a/src/qml/qml/qqmlvaluetype_p.h b/src/qml/qml/qqmlvaluetype_p.h
index 5a6bcdd003..2f6a192f77 100644
--- a/src/qml/qml/qqmlvaluetype_p.h
+++ b/src/qml/qml/qqmlvaluetype_p.h
@@ -57,34 +57,37 @@
 
 QT_BEGIN_NAMESPACE
 
-class Q_QML_PRIVATE_EXPORT QQmlValueType : public QObject
+class Q_QML_PRIVATE_EXPORT QQmlValueType : public QObject, public QAbstractDynamicMetaObject
 {
-    Q_OBJECT
 public:
-    QQmlValueType(int userType, QObject *parent = 0);
-    virtual void read(QObject *, int) = 0;
-    virtual void readVariantValue(QObject *, int, QVariant *) = 0;
-    virtual void write(QObject *, int, QQmlPropertyPrivate::WriteFlags flags) = 0;
-    virtual void writeVariantValue(QObject *, int, QQmlPropertyPrivate::WriteFlags, QVariant *) = 0;
-    virtual QVariant value() = 0;
-    virtual void setValue(const QVariant &) = 0;
-
-    virtual QString toString() const = 0;
-    virtual bool isEqual(const QVariant &value) const = 0;
-
-    virtual void onLoad() {}
+    QQmlValueType(int userType, const QMetaObject *metaObject);
+    ~QQmlValueType();
+    void read(QObject *, int);
+    void readVariantValue(QObject *, int, QVariant *);
+    void write(QObject *, int, QQmlPropertyPrivate::WriteFlags flags);
+    void writeVariantValue(QObject *, int, QQmlPropertyPrivate::WriteFlags, QVariant *);
+    QVariant value();
+    void setValue(const QVariant &);
+
+    QString toString() const;
+    bool isEqual(const QVariant &value) const;
 
     inline int userType() const
     {
-        return m_userType;
+        return typeId;
+
     }
+    // ---- dynamic meta object data interface
+    virtual QAbstractDynamicMetaObject *toDynamicMetaObject(QObject *);
+    virtual void objectDestroyed(QObject *);
+    virtual int metaCall(QObject *obj, QMetaObject::Call type, int _id, void **argv);
+    // ----
 
 protected:
     inline void readProperty(QObject *obj, int idx, void *p)
     {
         void *a[] = { p, 0 };
         QMetaObject::metacall(obj, QMetaObject::ReadProperty, idx, a);
-        onLoad();
     }
 
     inline void writeProperty(QObject *obj, int idx, QQmlPropertyPrivate::WriteFlags flags, void *p)
@@ -95,59 +98,9 @@ protected:
     }
 
 private:
-    int m_userType;
-};
-
-template <typename T>
-class QQmlValueTypeBase : public QQmlValueType
-{
-public:
-    typedef T ValueType;
-
-    QQmlValueTypeBase(int userType, QObject *parent)
-        : QQmlValueType(userType, parent)
-    {
-    }
-
-    virtual void read(QObject *obj, int idx)
-    {
-        readProperty(obj, idx, &v);
-    }
-
-    virtual void readVariantValue(QObject *obj, int idx, QVariant *into)
-    {
-        // important: must not change the userType of the variant
-        readProperty(obj, idx, into);
-    }
-
-    virtual void write(QObject *obj, int idx, QQmlPropertyPrivate::WriteFlags flags)
-    {
-        writeProperty(obj, idx, flags, &v);
-    }
-
-    virtual void writeVariantValue(QObject *obj, int idx, QQmlPropertyPrivate::WriteFlags flags, QVariant *from)
-    {
-        writeProperty(obj, idx, flags, from);
-    }
-
-    virtual QVariant value()
-    {
-        return QVariant::fromValue(v);
-    }
-
-    virtual void setValue(const QVariant &value)
-    {
-        v = qvariant_cast<T>(value);
-        onLoad();
-    }
-
-    virtual bool isEqual(const QVariant &other) const
-    {
-        return QVariant::fromValue(v) == other;
-    }
-
-protected:
-    ValueType v;
+    const QMetaObject *_metaObject;
+    int typeId;
+    void *gadgetPtr;
 };
 
 class Q_QML_PRIVATE_EXPORT QQmlValueTypeFactory
@@ -155,86 +108,75 @@ class Q_QML_PRIVATE_EXPORT QQmlValueTypeFactory
 public:
     static bool isValueType(int);
     static QQmlValueType *valueType(int idx);
+    static const QMetaObject *metaObjectForMetaType(int type);
 
     static void registerValueTypes(const char *uri, int versionMajor, int versionMinor);
 };
 
-class Q_QML_PRIVATE_EXPORT QQmlPointFValueType : public QQmlValueTypeBase<QPointF>
+struct QQmlPointFValueType
 {
+    QPointF v;
     Q_PROPERTY(qreal x READ x WRITE setX FINAL)
     Q_PROPERTY(qreal y READ y WRITE setY FINAL)
-    Q_OBJECT
+    Q_GADGET
 public:
-    QQmlPointFValueType(QObject *parent = 0);
-
-    virtual QString toString() const;
-
+    Q_INVOKABLE QString toString() const;
     qreal x() const;
     qreal y() const;
     void setX(qreal);
     void setY(qreal);
 };
 
-class Q_QML_PRIVATE_EXPORT QQmlPointValueType : public QQmlValueTypeBase<QPoint>
+struct QQmlPointValueType
 {
+    QPoint v;
     Q_PROPERTY(int x READ x WRITE setX FINAL)
     Q_PROPERTY(int y READ y WRITE setY FINAL)
-    Q_OBJECT
+    Q_GADGET
 public:
-    QQmlPointValueType(QObject *parent = 0);
-
-    virtual QString toString() const;
-
     int x() const;
     int y() const;
     void setX(int);
     void setY(int);
 };
 
-class Q_QML_PRIVATE_EXPORT QQmlSizeFValueType : public QQmlValueTypeBase<QSizeF>
+struct QQmlSizeFValueType
 {
+    QSizeF v;
     Q_PROPERTY(qreal width READ width WRITE setWidth FINAL)
     Q_PROPERTY(qreal height READ height WRITE setHeight FINAL)
-    Q_OBJECT
+    Q_GADGET
 public:
-    QQmlSizeFValueType(QObject *parent = 0);
-
-    virtual QString toString() const;
-
+    Q_INVOKABLE QString toString() const;
     qreal width() const;
     qreal height() const;
     void setWidth(qreal);
     void setHeight(qreal);
 };
 
-class Q_QML_PRIVATE_EXPORT QQmlSizeValueType : public QQmlValueTypeBase<QSize>
+struct QQmlSizeValueType
 {
+    QSize v;
     Q_PROPERTY(int width READ width WRITE setWidth FINAL)
     Q_PROPERTY(int height READ height WRITE setHeight FINAL)
-    Q_OBJECT
+    Q_GADGET
 public:
-    QQmlSizeValueType(QObject *parent = 0);
-
-    virtual QString toString() const;
-
     int width() const;
     int height() const;
     void setWidth(int);
     void setHeight(int);
 };
 
-class Q_QML_PRIVATE_EXPORT QQmlRectFValueType : public QQmlValueTypeBase<QRectF>
+struct QQmlRectFValueType
 {
+    QRectF v;
     Q_PROPERTY(qreal x READ x WRITE setX FINAL)
     Q_PROPERTY(qreal y READ y WRITE setY FINAL)
     Q_PROPERTY(qreal width READ width WRITE setWidth FINAL)
     Q_PROPERTY(qreal height READ height WRITE setHeight FINAL)
-    Q_OBJECT
+    Q_GADGET
 public:
-    QQmlRectFValueType(QObject *parent = 0);
-
-    virtual QString toString() const;
-
+    Q_INVOKABLE QString toString() const;
     qreal x() const;
     qreal y() const;
     void setX(qreal);
@@ -246,18 +188,15 @@ public:
     void setHeight(qreal);
 };
 
-class Q_QML_PRIVATE_EXPORT QQmlRectValueType : public QQmlValueTypeBase<QRect>
+struct QQmlRectValueType
 {
+    QRect v;
     Q_PROPERTY(int x READ x WRITE setX FINAL)
     Q_PROPERTY(int y READ y WRITE setY FINAL)
     Q_PROPERTY(int width READ width WRITE setWidth FINAL)
     Q_PROPERTY(int height READ height WRITE setHeight FINAL)
-    Q_OBJECT
+    Q_GADGET
 public:
-    QQmlRectValueType(QObject *parent = 0);
-
-    virtual QString toString() const;
-
     int x() const;
     int y() const;
     void setX(int);
@@ -269,9 +208,10 @@ public:
     void setHeight(int);
 };
 
-class Q_QML_PRIVATE_EXPORT QQmlEasingValueType : public QQmlValueTypeBase<QEasingCurve>
+struct QQmlEasingValueType
 {
-    Q_OBJECT
+    QEasingCurve v;
+    Q_GADGET
     Q_ENUMS(Type)
 
     Q_PROPERTY(QQmlEasingValueType::Type type READ type WRITE setType FINAL)
@@ -307,10 +247,6 @@ public:
         Bezier = QEasingCurve::BezierSpline
     };
 
-    QQmlEasingValueType(QObject *parent = 0);
-
-    virtual QString toString() const;
-
     Type type() const;
     qreal amplitude() const;
     qreal overshoot() const;