Make cloning available to third party QNodes

Third party QNode subclasses won't have access to QNodePrivate, so move
the clone() operation as a protected static method on QNode itself. This
way third party nodes can implement deep copy in their copy()
implementation as expected.

Change-Id: I59d0414f4ea9c679f2b7e197ea90e36bd8a915a4
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

4 files changed, 38 insertions, 43 deletions

diff --git a/src/core/nodes/qentity.cpp b/src/core/nodes/qentity.cpp
index 69abb83bd..a65a1d704 100644
--- a/src/core/nodes/qentity.cpp
+++ b/src/core/nodes/qentity.cpp
@@ -86,7 +86,7 @@ void QEntity::copy(const QNode *ref)
     d_func()->m_visible = entity->d_func()->m_visible;
 
     Q_FOREACH (QComponent *c, entity->d_func()->m_components) {
-        QNode *ccclone = QNodePrivate::get(c)->clone();
+        QNode *ccclone = QNode::clone(c);
         addComponent(qobject_cast<QComponent *>(ccclone));
     }
 }
@@ -115,7 +115,7 @@ void QEntity::addComponent(QComponent *comp)
     if (d->m_changeArbiter != Q_NULLPTR) {
         QScenePropertyChangePtr propertyChange(new QScenePropertyChange(ComponentAdded, this));
         propertyChange->setPropertyName(QByteArrayLiteral("component"));
-        propertyChange->setValue(QVariant::fromValue(QNodePtr(QNodePrivate::get(comp)->clone(), &QNodePrivate::nodePtrDeleter)));
+        propertyChange->setValue(QVariant::fromValue(QNodePtr(QNode::clone(comp), &QNodePrivate::nodePtrDeleter)));
         d->notifyObservers(propertyChange);
     }
     static_cast<QComponentPrivate *>(QComponentPrivate::get(comp))->addEntity(this);
@@ -131,7 +131,7 @@ void QEntity::removeComponent(QComponent *comp)
 
     if (d->m_changeArbiter != Q_NULLPTR) {
         QScenePropertyChangePtr propertyChange(new QScenePropertyChange(ComponentRemoved, this));
-        propertyChange->setValue(QVariant::fromValue(QNodePtr(QNodePrivate::get(comp)->clone(), &QNodePrivate::nodePtrDeleter)));
+        propertyChange->setValue(QVariant::fromValue(QNodePtr(QNode::clone(comp), &QNodePrivate::nodePtrDeleter)));
         propertyChange->setPropertyName(QByteArrayLiteral("component"));
         d->notifyObservers(propertyChange);
     }
diff --git a/src/core/nodes/qnode.cpp b/src/core/nodes/qnode.cpp
index 959cf3ab6..6df130dcb 100644
--- a/src/core/nodes/qnode.cpp
+++ b/src/core/nodes/qnode.cpp
@@ -92,7 +92,7 @@ void QNodePrivate::addChild(QNode *childNode)
         QScenePropertyChangePtr e(new QScenePropertyChange(NodeCreated, q));
         e->setPropertyName(QByteArrayLiteral("node"));
         // We need to clone the parent of the childNode we send
-        QNode *parentClone = clone();
+        QNode *parentClone = QNode::clone(q_func());
         QNode *childClone = Q_NULLPTR;
         Q_FOREACH (QObject *c, parentClone->children()) {
             QNode *clone = qobject_cast<QNode *>(c);
@@ -119,7 +119,7 @@ void QNodePrivate::removeChild(QNode *childNode)
         QScenePropertyChangePtr e(new QScenePropertyChange(NodeAboutToBeDeleted, q));
         e->setPropertyName(QByteArrayLiteral("node"));
         // We need to clone the parent of the childNode we send
-        QNode *parentClone = clone();
+        QNode *parentClone = QNode::clone(q_func());
         QNode *childClone = Q_NULLPTR;
         Q_FOREACH (QObject *c, parentClone->children()) {
             QNode *clone = qobject_cast<QNode *>(c);
@@ -137,41 +137,6 @@ void QNodePrivate::removeChild(QNode *childNode)
     childNode->d_func()->setScene(Q_NULLPTR);
 }
 
-// In most cases isClone is true so that the clone isn't handled like
-// a real node. If there is a need for a real clone, set isClone to false
-// eg When a subtree built in the backend needs to be cloned
-// in the main thread to be added to the scene graph
-QNode *QNodePrivate::clone()
-{
-    static int clearLock = 0;
-    clearLock++;
-
-    // We keep a reference of clones for the current subtree
-    // In order to preserve relationships when multiple entities
-    // reference the same component
-    QNode *clonedNode = QNodePrivate::m_clonesLookupTable.value(m_uuid);
-    if (clonedNode == Q_NULLPTR) {
-        Q_Q(QNode);
-        clonedNode = q->doClone();
-        // doClone, returns new instance with content copied
-        // and relationships added
-        QNodePrivate::m_clonesLookupTable.insert(clonedNode->uuid(), clonedNode);
-    }
-    Q_FOREACH (QObject *c, q_ptr->children()) {
-        QNode *childNode = qobject_cast<QNode *>(c);
-        if (childNode != Q_NULLPTR) {
-            QNode *cclone = childNode->d_func()->clone();
-            if (cclone != Q_NULLPTR)
-                cclone->setParent(clonedNode);
-        }
-    }
-
-    if (--clearLock == 0)
-        QNodePrivate::m_clonesLookupTable.clear();
-
-    return clonedNode;
-}
-
 void QNodePrivate::removeAllChildren()
 {
     Q_FOREACH (QObject *child, q_ptr->children()) {
@@ -386,6 +351,36 @@ bool QNode::blockNotifications(bool block)
     return previous;
 }
 
+QNode *QNode::clone(QNode *node)
+{
+    static int clearLock = 0;
+    clearLock++;
+
+    // We keep a reference of clones for the current subtree
+    // In order to preserve relationships when multiple entities
+    // reference the same component
+    QNode *clonedNode = QNodePrivate::m_clonesLookupTable.value(node->uuid());
+    if (clonedNode == Q_NULLPTR) {
+        clonedNode = node->doClone();
+        // doClone, returns new instance with content copied
+        // and relationships added
+        QNodePrivate::m_clonesLookupTable.insert(clonedNode->uuid(), clonedNode);
+    }
+    Q_FOREACH (QObject *c, node->children()) {
+        QNode *childNode = qobject_cast<QNode *>(c);
+        if (childNode != Q_NULLPTR) {
+            QNode *cclone = QNode::clone(childNode);
+            if (cclone != Q_NULLPTR)
+                cclone->setParent(clonedNode);
+        }
+    }
+
+    if (--clearLock == 0)
+        QNodePrivate::m_clonesLookupTable.clear();
+
+    return clonedNode;
+}
+
 bool QNode::event(QEvent *e)
 {
     Q_D(QNode);
diff --git a/src/core/nodes/qnode.h b/src/core/nodes/qnode.h
index 01da4d961..3235d0a7e 100644
--- a/src/core/nodes/qnode.h
+++ b/src/core/nodes/qnode.h
@@ -81,6 +81,9 @@ public:
     bool blockNotifications(bool block);
 
 protected:
+    // Clone should only be made in the main thread
+    static QNode *clone(QNode *node);
+
     QNode(QNodePrivate &dd, QNode *parent = 0);
     virtual void copy(const QNode *ref);
     virtual void sceneChangeEvent(const QSceneChangePtr &change);
diff --git a/src/core/nodes/qnode_p.h b/src/core/nodes/qnode_p.h
index 4271f7d13..fc238024d 100644
--- a/src/core/nodes/qnode_p.h
+++ b/src/core/nodes/qnode_p.h
@@ -61,9 +61,6 @@ class QT3DCORESHARED_EXPORT QNodePrivate : public QObjectPrivate, public QObserv
 public:
     QNodePrivate(QNode *qq);
 
-    // Clone should only be made in the main thread
-    QNode *clone();
-
     void setScene(QSceneInterface *scene);
     QSceneInterface *scene() const;