Use QQmlRefCount for QQmlType(Private)

As we already have an implementation of refcounting, we can just use
that intead of inventing another one. This also gives us nice move ctors
and operators.

Also, use const pointers to QQmlTypePrivate where possible. This exposes
quite some nastiness that needs to be fixed in follow-up commits: All
the mutable members of QQmlTypePrivate are unsafe for multithreaded use.

Change-Id: I3be8f2c53d86e06ffa80c8df8830473fe6d1d91d
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

6 files changed, 43 insertions, 67 deletions

diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index a034d72221..0da96f61e4 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -1220,7 +1220,7 @@ void QQmlMetaType::freeUnusedTypesAndCaches()
         QList<QQmlType>::Iterator it = data->types.begin();
         while (it != data->types.end()) {
             const QQmlTypePrivate *d = (*it).priv();
-            if (d && d->refCount == 1) {
+            if (d && d->count() == 1) {
                 deletedAtLeastOneType = true;
 
                 removeQQmlTypePrivate(data->idToType, d);
diff --git a/src/qml/qml/qqmlmetatypedata.cpp b/src/qml/qml/qqmlmetatypedata.cpp
index da5b4ec075..13c46e4911 100644
--- a/src/qml/qml/qqmlmetatypedata.cpp
+++ b/src/qml/qml/qqmlmetatypedata.cpp
@@ -74,7 +74,7 @@ void QQmlMetaTypeData::registerType(QQmlTypePrivate *priv)
     }
     types.append(QQmlType(priv));
     priv->index = types.count() - 1;
-    priv->refCount.deref();
+    priv->release();
 }
 
 QQmlPropertyCache *QQmlMetaTypeData::propertyCache(const QMetaObject *metaObject, int minorVersion)
diff --git a/src/qml/qml/qqmltype.cpp b/src/qml/qml/qqmltype.cpp
index a4adb18f76..efe190cbcf 100644
--- a/src/qml/qml/qqmltype.cpp
+++ b/src/qml/qml/qqmltype.cpp
@@ -116,7 +116,7 @@ QJSValue QQmlType::SingletonInstanceInfo::scriptApi(QQmlEngine *e) const
 }
 
 QQmlTypePrivate::QQmlTypePrivate(QQmlType::RegistrationType type)
-    : refCount(1), regType(type), iid(nullptr), typeId(0), listId(0), revision(0),
+    : regType(type), iid(nullptr), typeId(0), listId(0), revision(0),
     containsRevisionedAttributes(false), baseMetaObject(nullptr),
     index(-1), isSetup(false), isEnumSetup(false), haveSuperType(false)
 {
@@ -155,6 +155,10 @@ QQmlTypePrivate::~QQmlTypePrivate()
     qDeleteAll(scopedEnums);
     switch (regType) {
     case QQmlType::CppType:
+        // If attached properties were successfully registered, deregister them.
+        // (They may not have been registered if some other type used the same baseMetaObject)
+        if (extraData.cd->attachedPropertiesType)
+            QQmlMetaType::unregisterAttachedPropertyId(baseMetaObject, index);
         delete extraData.cd->customParser;
         delete extraData.cd;
         break;
@@ -171,47 +175,13 @@ QQmlTypePrivate::~QQmlTypePrivate()
     }
 }
 
-QQmlType::QQmlType()
-    : d(nullptr)
-{
-}
-
-QQmlType::QQmlType(const QQmlType &other)
-    : d(other.d)
-{
-    if (d)
-        d->refCount.ref();
-}
-
-QQmlType &QQmlType::operator =(const QQmlType &other)
-{
-    if (d != other.d) {
-        if (d && !d->refCount.deref())
-            delete d;
-        d = other.d;
-        if (d)
-            d->refCount.ref();
-    }
-    return *this;
-}
-
-QQmlType::QQmlType(QQmlTypePrivate *priv)
-    : d(priv)
-{
-    if (d)
-        d->refCount.ref();
-}
-
-QQmlType::~QQmlType()
-{
-    if (d && !d->refCount.deref()) {
-        // If attached properties were successfully registered, deregister them.
-        // (They may not have been registered if some other type used the same baseMetaObject)
-        if (d->regType == CppType && d->extraData.cd->attachedPropertiesType)
-            QQmlMetaType::unregisterAttachedPropertyId(d->baseMetaObject, d->index);
-        delete d;
-    }
-}
+QQmlType::QQmlType() = default;
+QQmlType::QQmlType(const QQmlType &other) = default;
+QQmlType::QQmlType(QQmlType &&other) = default;
+QQmlType &QQmlType::operator =(const QQmlType &other) = default;
+QQmlType &QQmlType::operator =(QQmlType &&other) = default;
+QQmlType::QQmlType(const QQmlTypePrivate *priv) : d(priv) {}
+QQmlType::~QQmlType() = default;
 
 QHashedString QQmlType::module() const
 {
@@ -985,22 +955,22 @@ int QQmlType::scopedEnumValue(QQmlEnginePrivate *engine, const QStringRef &scope
     return -1;
 }
 
-void QQmlType::refHandle(QQmlTypePrivate *priv)
+void QQmlType::refHandle(const QQmlTypePrivate *priv)
 {
     if (priv)
-        priv->refCount.ref();
+        priv->addref();
 }
 
-void QQmlType::derefHandle(QQmlTypePrivate *priv)
+void QQmlType::derefHandle(const QQmlTypePrivate *priv)
 {
-    if (priv && !priv->refCount.deref())
-        delete priv;
+    if (priv)
+        priv->release();
 }
 
-int QQmlType::refCount(QQmlTypePrivate *priv)
+int QQmlType::refCount(const QQmlTypePrivate *priv)
 {
     if (priv)
-        return priv->refCount;
+        return priv->count();
     return -1;
 }
 
diff --git a/src/qml/qml/qqmltype_p.h b/src/qml/qml/qqmltype_p.h
index 969c096aeb..1d1345a0cb 100644
--- a/src/qml/qml/qqmltype_p.h
+++ b/src/qml/qml/qqmltype_p.h
@@ -52,6 +52,7 @@
 //
 
 #include <private/qtqmlglobal_p.h>
+#include <private/qqmlrefcount_p.h>
 
 #include <QtQml/qqmlprivate.h>
 #include <QtQml/qjsvalue.h>
@@ -77,16 +78,18 @@ class Q_QML_PRIVATE_EXPORT QQmlType
 public:
     QQmlType();
     QQmlType(const QQmlType &other);
+    QQmlType(QQmlType &&other);
     QQmlType &operator =(const QQmlType &other);
-    explicit QQmlType(QQmlTypePrivate *priv);
+    QQmlType &operator =(QQmlType &&other);
+    explicit QQmlType(const QQmlTypePrivate *priv);
     ~QQmlType();
 
     bool operator ==(const QQmlType &other) const {
-        return d == other.d;
+        return d.data() == other.d.data();
     }
 
-    bool isValid() const { return d != nullptr; }
-    const QQmlTypePrivate *key() const { return d; }
+    bool isValid() const { return !d.isNull(); }
+    const QQmlTypePrivate *key() const { return d.data(); }
 
     QByteArray typeName() const;
     QString qmlTypeName() const;
@@ -174,10 +177,10 @@ public:
     int scopedEnumValue(QQmlEnginePrivate *engine, const QByteArray &, const QByteArray &, bool *ok) const;
     int scopedEnumValue(QQmlEnginePrivate *engine, const QStringRef &, const QStringRef &, bool *ok) const;
 
-    QQmlTypePrivate *priv() const { return d; }
-    static void refHandle(QQmlTypePrivate *priv);
-    static void derefHandle(QQmlTypePrivate *priv);
-    static int refCount(QQmlTypePrivate *priv);
+    const QQmlTypePrivate *priv() const { return d.data(); }
+    static void refHandle(const QQmlTypePrivate *priv);
+    static void derefHandle(const QQmlTypePrivate *priv);
+    static int refCount(const QQmlTypePrivate *priv);
 
     enum RegistrationType {
         CppType = 0,
@@ -195,10 +198,13 @@ private:
     QQmlPropertyCache *compositePropertyCache(QQmlEnginePrivate *engine) const;
     friend uint qHash(const QQmlType &t, uint seed);
 
-    QQmlTypePrivate *d;
+    QQmlRefPointer<const QQmlTypePrivate> d;
 };
 
-inline uint qHash(const QQmlType &t, uint seed = 0) { return qHash(reinterpret_cast<quintptr>(t.d), seed); }
+inline uint qHash(const QQmlType &t, uint seed = 0)
+{
+    return qHash(reinterpret_cast<quintptr>(t.d.data()), seed);
+}
 
 QT_END_NAMESPACE
 
diff --git a/src/qml/qml/qqmltype_p_p.h b/src/qml/qml/qqmltype_p_p.h
index 51984dd360..380139f385 100644
--- a/src/qml/qml/qqmltype_p_p.h
+++ b/src/qml/qml/qqmltype_p_p.h
@@ -59,19 +59,17 @@
 
 QT_BEGIN_NAMESPACE
 
-class QQmlTypePrivate
+class QQmlTypePrivate : public QQmlRefCount
 {
-    Q_DISABLE_COPY(QQmlTypePrivate)
+    Q_DISABLE_COPY_MOVE(QQmlTypePrivate)
 public:
     QQmlTypePrivate(QQmlType::RegistrationType type);
-    ~QQmlTypePrivate();
 
     void init() const;
     void initEnums(const QQmlPropertyCache *cache = nullptr) const;
     void insertEnums(const QMetaObject *metaObject) const;
     void insertEnumsFromPropertyCache(const QQmlPropertyCache *cache) const;
 
-    QAtomicInt refCount;
     QQmlType::RegistrationType regType;
 
     struct QQmlCppTypeData
@@ -143,6 +141,8 @@ public:
     void setName(const QString &uri, const QString &element);
 
 private:
+    ~QQmlTypePrivate() override;
+
     struct EnumInfo {
         QStringList path;
         QString metaObjectName;
diff --git a/src/qml/qml/qqmltypewrapper_p.h b/src/qml/qml/qqmltypewrapper_p.h
index fa1ad56902..bc615e0f6c 100644
--- a/src/qml/qml/qqmltypewrapper_p.h
+++ b/src/qml/qml/qqmltypewrapper_p.h
@@ -81,7 +81,7 @@ struct QQmlTypeWrapper : Object {
 
     QQmlType type() const;
 
-    QQmlTypePrivate *typePrivate;
+    const QQmlTypePrivate *typePrivate;
     QQmlTypeNameCache *typeNamespace;
     const QQmlImportRef *importNamespace;
 };
@@ -90,7 +90,7 @@ struct QQmlScopedEnumWrapper : Object {
     void init() { Object::init(); }
     void destroy();
     int scopeEnumIndex;
-    QQmlTypePrivate *typePrivate;
+    const QQmlTypePrivate *typePrivate;
     QQmlType type() const;
 };