Add infrastructure to connect properties from Quick API to the Q3DS API

Removes the syncProperties() function, as it's strictly not needed
anymore. If there's a need to intercept one or more property change,
two different options are provided:
1. Add a property on the target object that is prefixed with "qq_" or
2. Re-implement the propertChanged() function.

Change-Id: If2ef181f09f17916b0d2d9606663175958e46e77
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

9 files changed, 129 insertions, 30 deletions

diff --git a/src/runtime/aping/q3dsgroup3d.cpp b/src/runtime/aping/q3dsgroup3d.cpp
index 98f83fe..76d45a3 100644
--- a/src/runtime/aping/q3dsgroup3d.cpp
+++ b/src/runtime/aping/q3dsgroup3d.cpp
@@ -58,16 +58,7 @@ Q3DSGraphObject *Q3DSGroup3D::createObject(Q3DSUipPresentation *presentation)
     Q3DSGraphObject *obj = presentation->newObject<Q3DSGroupNode>(id);
     obj->setName(QString::fromLatin1(id));
 
-    syncProperties();
-
     return obj;
 }
 
-void Q3DSGroup3D::syncProperties()
-{
-    Q3DSNode3D::syncProperties();
-
-    // ###
-}
-
 QT_END_NAMESPACE
diff --git a/src/runtime/aping/q3dsgroup3d_p.h b/src/runtime/aping/q3dsgroup3d_p.h
index 506b08d..de8f3f4 100644
--- a/src/runtime/aping/q3dsgroup3d_p.h
+++ b/src/runtime/aping/q3dsgroup3d_p.h
@@ -56,7 +56,6 @@ public:
     Q3DSGroupNode *groupNode() const { return static_cast<Q3DSGroupNode *>(object()); }
 
     Q3DSGraphObject *createObject(Q3DSUipPresentation *presentation) override;
-    void syncProperties() override;
 };
 
 QT_END_NAMESPACE
diff --git a/src/runtime/aping/q3dslayer3d.cpp b/src/runtime/aping/q3dslayer3d.cpp
index e783198..50f9eb4 100644
--- a/src/runtime/aping/q3dslayer3d.cpp
+++ b/src/runtime/aping/q3dslayer3d.cpp
@@ -243,8 +243,6 @@ void Q3DSLayer3D::sync()
             m_engine->handleViewGeometryChange(this, sz);
         }
 
-        syncProperties();
-
         // Notify the waiting Object3D, if there is one, to create its subtree
         // and parent it to our m_layer3DS.
         emit layerNodeCreated();
@@ -380,9 +378,4 @@ void Q3DSLayer3D::touchEvent(QTouchEvent *event)
         m_engine->engine()->handleTouchEvent(event, m_layer3DS);
 }
 
-void Q3DSLayer3D::syncProperties()
-{
-    // ###
-}
-
 QT_END_NAMESPACE
diff --git a/src/runtime/aping/q3dslayer3d_p.h b/src/runtime/aping/q3dslayer3d_p.h
index 571a83e..f1f43bb 100644
--- a/src/runtime/aping/q3dslayer3d_p.h
+++ b/src/runtime/aping/q3dslayer3d_p.h
@@ -78,8 +78,6 @@ public:
 
     bool isLive() const { return layerNode() && presentation(); }
 
-    void syncProperties();
-
 signals:
     void engineChanged();
     void layerNodeCreated();
diff --git a/src/runtime/aping/q3dsnode3d.cpp b/src/runtime/aping/q3dsnode3d.cpp
index 58873c3..a885491 100644
--- a/src/runtime/aping/q3dsnode3d.cpp
+++ b/src/runtime/aping/q3dsnode3d.cpp
@@ -50,11 +50,4 @@ Q3DSNode3D::~Q3DSNode3D()
 {
 }
 
-void Q3DSNode3D::syncProperties()
-{
-    Q3DSObject3D::syncProperties();
-
-    // ###
-}
-
 QT_END_NAMESPACE
diff --git a/src/runtime/aping/q3dsnode3d_p.h b/src/runtime/aping/q3dsnode3d_p.h
index 9ec5d77..88e61c8 100644
--- a/src/runtime/aping/q3dsnode3d_p.h
+++ b/src/runtime/aping/q3dsnode3d_p.h
@@ -54,8 +54,6 @@ public:
     ~Q3DSNode3D();
 
     Q3DSNode *node() const { return static_cast<Q3DSNode *>(object()); }
-
-    void syncProperties() override;
 };
 
 QT_END_NAMESPACE
diff --git a/src/runtime/aping/q3dsobject3d.cpp b/src/runtime/aping/q3dsobject3d.cpp
index 54dfcd8..256845e 100644
--- a/src/runtime/aping/q3dsobject3d.cpp
+++ b/src/runtime/aping/q3dsobject3d.cpp
@@ -179,6 +179,17 @@ void Q3DSObject3D::activate()
     // Connect the object and its children to the Q3DSLayerNode. If that is
     // parented to a scene then the subtree becomes alive now.
     m_layer->layerNode()->appendChildNode(m_object);
+
+    // Sync the properties and make sure they continue being updated.
+    syncProperties();
+    Q3DSPropertyBinder *binder = nullptr;
+    const QVariant v = property(Q3DSPropertyBinder::binderName());
+    if (v.isValid())
+        binder = v.value<Q3DSPropertyBinder *>();
+
+    if (!binder)
+        binder = new Q3DSPropertyBinder(this);
+    binder->bind(this, m_object);
 }
 
 void Q3DSObject3D::setLayer_recursive(Q3DSLayer3D *layer)
@@ -215,9 +226,35 @@ QByteArray Q3DSObject3D::makeIdAndName() const
     return id;
 }
 
+void Q3DSObject3D::propertyChanged(const QMetaProperty &sp,
+                                   Q3DSGraphObject *target,
+                                   const QMetaProperty &tp)
+{
+    if (!target || !tp.isValid())
+        return;
+
+    const QVariant &v = sp.read(this);
+    if (!tp.writeOnGadget(target, v)) {
+        qWarning("Failed to write property %s on %s", sp.name(), target->id().constData());
+        return;
+    }
+    const QString propName = QString::fromLatin1((!::strncmp(tp.name(), "qq_", 3)) ? tp.name() + 3 : tp.name());
+    target->notifyPropertyChanges({propName, QString()});
+}
+
 void Q3DSObject3D::syncProperties()
 {
-    // ###
+    Q_ASSERT(m_object);
+    // This is a bit crude, but it's only called once, so it's good enough for now.
+    const int propCount = metaObject()->propertyCount();
+    for (int i = 0; i != propCount; ++i) {
+        const auto property = metaObject()->property(i);
+        const QByteArray name = QByteArrayLiteral("qq_") + property.name();
+        int idx = m_object->metaObject()->indexOfProperty(name.constData());
+        if (idx < 0)
+            idx = m_object->metaObject()->indexOfProperty(name.constData() + 3);
+        propertyChanged(property, m_object, (idx >= 0) ? m_object->metaObject()->property(idx) : QMetaProperty());
+    }
 }
 
 QT_END_NAMESPACE
diff --git a/src/runtime/aping/q3dsobject3d_p.h b/src/runtime/aping/q3dsobject3d_p.h
index e588fdc..f055cef 100644
--- a/src/runtime/aping/q3dsobject3d_p.h
+++ b/src/runtime/aping/q3dsobject3d_p.h
@@ -58,7 +58,6 @@ public:
     ~Q3DSObject3D();
 
     virtual Q3DSGraphObject *createObject(Q3DSUipPresentation *presentation) = 0;
-    virtual void syncProperties();
 
     Q3DSGraphObject *object() const { return m_object; }
     Q3DSLayer3D *layer() const { return m_layer; }
@@ -74,11 +73,15 @@ public:
 protected:
     void itemChange(ItemChange, const ItemChangeData &) override;
     QByteArray makeIdAndName() const;
+    virtual void propertyChanged(const QMetaProperty &sp,
+                                 Q3DSGraphObject *target,
+                                 const QMetaProperty &tp);
 
 private:
     void activate();
     void activate_helper(Q3DSLayer3D *layer);
     void setLayer_recursive(Q3DSLayer3D *layer);
+    void syncProperties();
 
     Q3DSGraphObject *m_object = nullptr;
     Q3DSLayer3D *m_layer = nullptr;
@@ -87,10 +90,90 @@ private:
     QMetaObject::Connection m_layerConn;
 
     friend class Q3DSLayer3D;
+    friend class Q3DSPropertyBinder;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(Q3DSObject3D::InvalidateFlags)
 
+class Q3DSPropertyBinder : public QObject
+{
+public:
+    ~Q3DSPropertyBinder() { unbind(); }
+    static QByteArray binderName() { return QByteArrayLiteral("_q3dsbinding"); }
+    static QByteArray propertyPrefix() { return QByteArrayLiteral("qq_"); }
+
+    Q3DSPropertyBinder(QObject *p = nullptr) : QObject(p) {}
+    int qt_metacall(QMetaObject::Call call, int methodId, void **args) override
+    {
+        methodId = QObject::qt_metacall(call, methodId, args);
+        if (methodId < 0)
+            return methodId;
+
+        if (!m_dst || !m_src)
+            return  methodId;
+
+        if (call == QMetaObject::InvokeMetaMethod) {
+            QMetaProperty sp = m_src->metaObject()->property(methodId);
+            const int dstIdx = m_propMap[methodId];
+            QMetaProperty tp = (dstIdx >= 0) ? m_dst->metaObject()->property(dstIdx)
+                                             : QMetaProperty();
+            m_src->propertyChanged(sp, m_dst, tp);
+            return -1;
+        }
+        return methodId;
+    }
+
+    void bind(Q3DSObject3D *src, Q3DSGraphObject *dst)
+    {
+        if (src == m_src && dst == m_dst)
+            return;
+
+        unbind();
+
+        m_src = src;
+        m_src->setProperty(binderName(), QVariant::fromValue(this));
+        m_dst = dst;
+        m_dst->setProperty(binderName(), QVariant::fromValue(this));
+        const int propCount = src->metaObject()->propertyCount();
+        for (int i = 0; i != propCount; ++i) {
+            const auto property = src->metaObject()->property(i);
+            if (!property.hasNotifySignal())
+                continue;
+            const QByteArray name = propertyPrefix() + property.name();
+            int idx = dst->metaObject()->indexOfProperty(name.constData());
+            if (idx < 0)
+                idx = dst->metaObject()->indexOfProperty(name.constData() + 3);
+            m_propMap[i] = idx;
+            QMetaObject::connect(src, property.notifySignalIndex(), this, i + metaObject()->methodCount(), Qt::DirectConnection, nullptr);
+        }
+    }
+
+    Q_INVOKABLE void unbind()
+    {
+        if (m_src) {
+            const QVariant h = m_src->property(binderName());
+            Q_ASSERT(this == h.value<Q3DSPropertyBinder *>());
+            m_src->setProperty(binderName(), QVariant());
+        }
+
+        if (m_dst) {
+            const QVariant h = m_dst->property(binderName());
+            Q_ASSERT(this == h.value<Q3DSPropertyBinder *>());
+            m_dst->setProperty(binderName(), QVariant());
+        }
+
+        disconnect();
+        m_propMap.clear();
+        m_src = nullptr;
+        m_dst = nullptr;
+    }
+
+private:
+    QMap<int, int> m_propMap;
+    Q3DSObject3D *m_src = nullptr;
+    Q3DSGraphObject *m_dst = nullptr;
+};
+
 QT_END_NAMESPACE
 
 #endif // Q3DSOBJECT3D_P_H
diff --git a/src/runtime/q3dsuippresentation.cpp b/src/runtime/q3dsuippresentation.cpp
index 23836f0..11c2aa6 100644
--- a/src/runtime/q3dsuippresentation.cpp
+++ b/src/runtime/q3dsuippresentation.cpp
@@ -40,6 +40,7 @@
 #include <QtMath>
 #include <QImage>
 
+#include <QtCore/qobject.h>
 #include <QtCore/qmetaobject.h>
 
 QT_BEGIN_NAMESPACE
@@ -411,6 +412,12 @@ Q3DSGraphObject::Q3DSGraphObject(Q3DSGraphObject::Type type)
 
 Q3DSGraphObject::~Q3DSGraphObject()
 {
+    const QVariant v = property(QByteArrayLiteral("_q3dsbinding"));
+    if (v.isValid()) {
+        QObject *src = v.value<QObject *>();
+        QMetaObject::invokeMethod(src, "unbind", Qt::DirectConnection);
+    }
+
     destroyGraph();
     delete m_attached;
 }