Hook up some machinery ready for testing the no cloning approach

Task-number: QTBUG-51835
Change-Id: I4520bf38acc9b8a990d3f3bce3d96f2014c5637b
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

9 files changed, 93 insertions, 13 deletions

diff --git a/src/core/aspects/qabstractaspect.cpp b/src/core/aspects/qabstractaspect.cpp
index 20a393738..19ec5a1dd 100644
--- a/src/core/aspects/qabstractaspect.cpp
+++ b/src/core/aspects/qabstractaspect.cpp
@@ -181,6 +181,44 @@ QBackendNode *QAbstractAspectPrivate::createBackendNode(QNode *frontend) const
     return Q_NULLPTR;
 }
 
+QBackendNode *QAbstractAspectPrivate::createBackendNodeNoClone(const QNodeCreatedChangeBasePtr &change) const
+{
+    const QMetaObject *metaObj = change->metaObject();
+    QBackendNodeMapperPtr backendNodeMapper;
+    while (metaObj != Q_NULLPTR && backendNodeMapper.isNull()) {
+        backendNodeMapper = m_backendCreatorFunctors.value(metaObj);
+        metaObj = metaObj->superClass();
+    }
+
+    if (!backendNodeMapper)
+        return nullptr;
+
+    QBackendNode *backend = backendNodeMapper->get(change->subjectId());
+    if (backend != Q_NULLPTR)
+        return backend;
+    backend = backendNodeMapper->create(change);
+
+    // TODO: Find some place else to do all of this function from the arbiter
+    if (backend)
+        backend->initializeFromPeer(change);
+
+    // Backend could be null if the user decides that his functor should only
+    // perform some action when encountering a given type of item but doesn't need to
+    // return a QBackendNode pointer.
+    if (!backend)
+        return nullptr;
+
+    QBackendNodePrivate *backendPriv = QBackendNodePrivate::get(backend);
+    // TO DO: Find a way to specify the changes to observe
+    // Register backendNode with QChangeArbiter
+    if (m_arbiter != Q_NULLPTR) { // Unit tests may not have the arbiter registered
+        m_arbiter->registerObserver(backendPriv, backend->peerId(), AllChanges);
+        if (backend->mode() == QBackendNode::ReadWrite)
+            m_arbiter->scene()->addObservable(backendPriv, backend->peerId());
+    }
+    return backend;
+}
+
 void QAbstractAspectPrivate::clearBackendNode(QNode *frontend) const
 {
     const QMetaObject *metaObj = frontend->metaObject();
@@ -202,7 +240,7 @@ void QAbstractAspectPrivate::clearBackendNode(QNode *frontend) const
     }
 }
 
-void QAbstractAspectPrivate::setRootAndCreateNodes(QEntity *rootObject)
+void QAbstractAspectPrivate::setRootAndCreateNodes(QEntity *rootObject, const QVector<QNodeCreatedChangeBasePtr> &changes)
 {
     qCDebug(Aspects) << Q_FUNC_INFO << "rootObject =" << rootObject;
     if (rootObject == m_root)
@@ -211,8 +249,15 @@ void QAbstractAspectPrivate::setRootAndCreateNodes(QEntity *rootObject)
     m_root = rootObject;
     m_rootId = rootObject->id();
 
-    QNodeVisitor visitor;
-    visitor.traverse(rootObject, this, &QAbstractAspectPrivate::createBackendNode);
+    // Use old method for now, unless user explicitly requests new method
+    const auto useNewMethod = qEnvironmentVariableIsSet("QT3D_NO_CLONE");
+    if (!useNewMethod) {
+        QNodeVisitor visitor;
+        visitor.traverse(rootObject, this, &QAbstractAspectPrivate::createBackendNode);
+    } else {
+        for (const auto &change : changes)
+            createBackendNodeNoClone(change);
+    }
 }
 
 QServiceLocator *QAbstractAspectPrivate::services() const
diff --git a/src/core/aspects/qabstractaspect_p.h b/src/core/aspects/qabstractaspect_p.h
index 5536f1e1d..28e1cac2f 100644
--- a/src/core/aspects/qabstractaspect_p.h
+++ b/src/core/aspects/qabstractaspect_p.h
@@ -80,7 +80,7 @@ class QT3DCORE_PRIVATE_EXPORT QAbstractAspectPrivate
 public:
     QAbstractAspectPrivate();
 
-    void setRootAndCreateNodes(QEntity *rootObject);
+    void setRootAndCreateNodes(QEntity *rootObject, const QVector<Qt3DCore::QNodeCreatedChangeBasePtr> &changes);
 
     QServiceLocator *services() const;
     QAbstractAspectJobManager *jobManager() const;
@@ -88,6 +88,9 @@ public:
     QVector<QAspectJobPtr> jobsToExecute(qint64 time) Q_DECL_OVERRIDE;
 
     QBackendNode *createBackendNode(QNode *frontend) const Q_DECL_OVERRIDE;
+    // TODO: Rename this to createBackendNode when new system is fully in place
+    QBackendNode *createBackendNodeNoClone(const QNodeCreatedChangeBasePtr &change) const Q_DECL_OVERRIDE;
+
     void clearBackendNode(QNode *frontend) const;
 
     void sceneNodeAdded(Qt3DCore::QSceneChangePtr &e) Q_DECL_OVERRIDE;
diff --git a/src/core/aspects/qaspectengine.cpp b/src/core/aspects/qaspectengine.cpp
index af6798407..b76aae603 100644
--- a/src/core/aspects/qaspectengine.cpp
+++ b/src/core/aspects/qaspectengine.cpp
@@ -331,11 +331,15 @@ void QAspectEngine::setRootEntity(QEntityPtr root)
     // Finally, tell the aspects about the new scene object tree. This is done
     // in a blocking manner to allow the aspects to get synchronized before the
     // main thread starts triggering potentially more notifications
+
+    // TODO: Pass the creation changes via the arbiter rather than relying upon
+    // an invokeMethod call.
     qCDebug(Aspects) << "Begin setting scene root on aspect manager";
     QMetaObject::invokeMethod(d->m_aspectThread->aspectManager(),
                               "setRootEntity",
                               Qt::BlockingQueuedConnection,
-                              Q_ARG(Qt3DCore::QEntity *, root.data()));
+                              Q_ARG(Qt3DCore::QEntity *, root.data()),
+                              Q_ARG(QVector<Qt3DCore::QNodeCreatedChangeBasePtr>, d->m_creationChanges));
     qCDebug(Aspects) << "Done setting scene root on aspect manager";
 
     d->m_aspectThread->aspectManager()->enterSimulationLoop();
diff --git a/src/core/aspects/qaspectmanager.cpp b/src/core/aspects/qaspectmanager.cpp
index 6155fa995..74b33f866 100644
--- a/src/core/aspects/qaspectmanager.cpp
+++ b/src/core/aspects/qaspectmanager.cpp
@@ -148,7 +148,7 @@ void QAspectManager::shutdown()
     // Aspects must be deleted in the Thread they were created in
 }
 
-void QAspectManager::setRootEntity(Qt3DCore::QEntity *root)
+void QAspectManager::setRootEntity(Qt3DCore::QEntity *root, const QVector<Qt3DCore::QNodeCreatedChangeBasePtr> &changes)
 {
     qCDebug(Aspects) << Q_FUNC_INFO;
 
@@ -164,7 +164,7 @@ void QAspectManager::setRootEntity(Qt3DCore::QEntity *root)
 
     if (m_root) {
         for (QAbstractAspect *aspect : qAsConst(m_aspects))
-            aspect->d_func()->setRootAndCreateNodes(m_root);
+            aspect->d_func()->setRootAndCreateNodes(m_root, changes);
     }
 }
 
diff --git a/src/core/aspects/qaspectmanager_p.h b/src/core/aspects/qaspectmanager_p.h
index 643da2311..99d29320e 100644
--- a/src/core/aspects/qaspectmanager_p.h
+++ b/src/core/aspects/qaspectmanager_p.h
@@ -52,6 +52,7 @@
 //
 
 #include <QObject>
+#include <Qt3DCore/qnodecreatedchange.h>
 #include <Qt3DCore/private/qt3dcore_global_p.h>
 #include <QList>
 #include <QScopedPointer>
@@ -89,7 +90,7 @@ public Q_SLOTS:
     void initialize();
     void shutdown();
 
-    void setRootEntity(Qt3DCore::QEntity *root);
+    void setRootEntity(Qt3DCore::QEntity *root, const QVector<Qt3DCore::QNodeCreatedChangeBasePtr> &changes);
     void registerAspect(Qt3DCore::QAbstractAspect *aspect);
 
     void exec();
diff --git a/src/core/nodes/qbackendnode.cpp b/src/core/nodes/qbackendnode.cpp
index 8dfc646ce..430d12cff 100644
--- a/src/core/nodes/qbackendnode.cpp
+++ b/src/core/nodes/qbackendnode.cpp
@@ -125,6 +125,13 @@ void QBackendNode::notifyObservers(const QSceneChangePtr &e)
     d->notifyObservers(e);
 }
 
+void QBackendNode::initializeFromPeer(const QNodeCreatedChangeBasePtr &change)
+{
+    // TODO: Put a warning/assert in here?
+    // Uncomment to see any backend nodes that do not implement this function yet
+    //qDebug() << Q_FUNC_INFO << change->metaObject()->className();
+}
+
 } // Qt3D
 
 QT_END_NAMESPACE
diff --git a/src/core/nodes/qbackendnode.h b/src/core/nodes/qbackendnode.h
index e8001e85d..5055e7986 100644
--- a/src/core/nodes/qbackendnode.h
+++ b/src/core/nodes/qbackendnode.h
@@ -42,6 +42,7 @@
 
 #include <Qt3DCore/qt3dcore_global.h>
 #include <Qt3DCore/qscenechange.h>
+#include <Qt3DCore/qnodecreatedchange.h>
 #include <Qt3DCore/qnodeid.h>
 
 QT_BEGIN_NAMESPACE
@@ -57,6 +58,13 @@ class QT3DCORESHARED_EXPORT QBackendNodeMapper
 public:
     virtual ~QBackendNodeMapper() {}
     virtual QBackendNode *create(QNode *frontend) const = 0;
+    // TODO: Make this pure virtual and remove QNode* overload
+    virtual QBackendNode *create(const QNodeCreatedChangeBasePtr &change) const
+    {
+        Q_UNUSED(change);
+        //qDebug() << "Functor with unimplemented create() function";
+        return nullptr;
+    }
     virtual QBackendNode *get(QNodeId id) const = 0;
     virtual void destroy(QNodeId id) const = 0;
 };
@@ -80,6 +88,10 @@ public:
     Mode mode() const Q_DECL_NOEXCEPT;
     virtual void updateFromPeer(QNode *peer) = 0;
 
+    // TODO: Make pure virtual
+    // TODO: Make protected/private
+    virtual void initializeFromPeer(const QNodeCreatedChangeBasePtr &change);
+
 protected:
     void notifyObservers(const QSceneChangePtr &e);
     virtual void sceneChangeEvent(const QSceneChangePtr &e) = 0;
diff --git a/src/core/qbackendnodefactory_p.h b/src/core/qbackendnodefactory_p.h
index 7cde150e5..732a2bacd 100644
--- a/src/core/qbackendnodefactory_p.h
+++ b/src/core/qbackendnodefactory_p.h
@@ -52,6 +52,7 @@
 //
 
 #include <Qt3DCore/private/qt3dcore_global_p.h>
+#include <Qt3DCore/qnodecreatedchange.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -65,6 +66,8 @@ class QT3DCORE_PRIVATE_EXPORT QBackendNodeFactory
 public:
     virtual ~QBackendNodeFactory();
     virtual QBackendNode *createBackendNode(QNode *frontend) const = 0;
+    // TODO: Rename this to createBackendNode when new system is fully in place
+    virtual QBackendNode *createBackendNodeNoClone(const QNodeCreatedChangeBasePtr &change) const = 0;
 };
 
 } // namespace Qt3DCore
diff --git a/tests/benchmarks/render/jobs/tst_bench_jobs.cpp b/tests/benchmarks/render/jobs/tst_bench_jobs.cpp
index 608c9ff16..362a363a7 100644
--- a/tests/benchmarks/render/jobs/tst_bench_jobs.cpp
+++ b/tests/benchmarks/render/jobs/tst_bench_jobs.cpp
@@ -233,7 +233,8 @@ private Q_SLOTS:
         QFETCH(Qt3DCore::QEntity*, rootEntity);
         TestAspect aspect;
 
-        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity));
+        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity),
+                                                                              QVector<Qt3DCore::QNodeCreatedChangeBasePtr>());
 
         // WHEN
         QVector<Qt3DCore::QAspectJobPtr> jobs = aspect.worldTransformJob();
@@ -256,7 +257,8 @@ private Q_SLOTS:
         QFETCH(Qt3DCore::QEntity*, rootEntity);
         TestAspect aspect;
 
-        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity));
+        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity),
+                                                                              QVector<Qt3DCore::QNodeCreatedChangeBasePtr>());
 
         // WHEN
         QVector<Qt3DCore::QAspectJobPtr> jobs = aspect.updateBoundingJob();
@@ -279,7 +281,8 @@ private Q_SLOTS:
         QFETCH(Qt3DCore::QEntity*, rootEntity);
         TestAspect aspect;
 
-        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity));
+        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity),
+                                                                              QVector<Qt3DCore::QNodeCreatedChangeBasePtr>());
 
         // WHEN
         QVector<Qt3DCore::QAspectJobPtr> jobs = aspect.calculateBoundingVolumeJob();
@@ -302,7 +305,8 @@ private Q_SLOTS:
         QFETCH(Qt3DCore::QEntity*, rootEntity);
         TestAspect aspect;
 
-        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity));
+        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity),
+                                                                              QVector<Qt3DCore::QNodeCreatedChangeBasePtr>());
 
         // WHEN
         QVector<Qt3DCore::QAspectJobPtr> jobs = aspect.framePreparationJob();
@@ -325,7 +329,8 @@ private Q_SLOTS:
         QFETCH(Qt3DCore::QEntity*, rootEntity);
         TestAspect aspect;
 
-        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity));
+        Qt3DCore::QAbstractAspectPrivate::get(&aspect)->setRootAndCreateNodes(qobject_cast<Qt3DCore::QEntity *>(rootEntity),
+                                                                              QVector<Qt3DCore::QNodeCreatedChangeBasePtr>());
 
         // WHEN
         QVector<Qt3DCore::QAspectJobPtr> jobs = aspect.frameCleanupJob();