Add QJSEngine::newQMetaObject

QJSEngine::newQMetaObject let us expose QMetaObject to the QJSEngine,
allowing to construct QObjects instance from javascript.

Additionally, enums values are exposed as property of the QMetaObject
wrapper.

(The engine takes ownership of the created objects)

Change-Id: I5428d4b7061cceacfa89f51e703dce3379b2c329
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 71 insertions, 28 deletions

diff --git a/src/qml/qml/qqmlpropertycache.cpp b/src/qml/qml/qqmlpropertycache.cpp
index 08d51ecfa1..562e7d1746 100644
--- a/src/qml/qml/qqmlpropertycache.cpp
+++ b/src/qml/qml/qqmlpropertycache.cpp
@@ -184,10 +184,16 @@ void QQmlPropertyData::load(const QMetaMethod &m)
 {
     coreIndex = m.methodIndex();
     arguments = 0;
+
+    propType = m.returnType();
+
     flags |= IsFunction;
     if (m.methodType() == QMetaMethod::Signal)
         flags |= IsSignal;
-    propType = m.returnType();
+    else if (m.methodType() == QMetaMethod::Constructor) {
+        flags |= IsConstructor;
+        propType = QMetaType::QObjectStar;
+    }
 
     if (m.parameterCount()) {
         flags |= HasArguments;
@@ -206,11 +212,15 @@ void QQmlPropertyData::load(const QMetaMethod &m)
 void QQmlPropertyData::lazyLoad(const QMetaMethod &m)
 {
     coreIndex = m.methodIndex();
+    propType = QMetaType::Void;
     arguments = 0;
     flags |= IsFunction;
     if (m.methodType() == QMetaMethod::Signal)
         flags |= IsSignal;
-    propType = QMetaType::Void;
+    else if (m.methodType() == QMetaMethod::Constructor) {
+        flags |= IsConstructor;
+        propType = QMetaType::QObjectStar;
+    }
 
     const char *returnType = m.typeName();
     if (!returnType)
@@ -1508,39 +1518,49 @@ int *QQmlMetaObject::methodParameterTypes(int index, QVarLengthArray<int, 9> &du
 
     } else {
         QMetaMethod m = _m.asT2()->method(index);
-        int argc = m.parameterCount();
-        dummy.resize(argc + 1);
-        dummy[0] = argc;
-        QList<QByteArray> argTypeNames; // Only loaded if needed
+        return methodParameterTypes(m, dummy, unknownTypeError);
 
-        for (int ii = 0; ii < argc; ++ii) {
-            int type = m.parameterType(ii);
-            QMetaType::TypeFlags flags = QMetaType::typeFlags(type);
-            if (flags & QMetaType::IsEnumeration)
-                type = QVariant::Int;
-            else if (type == QMetaType::UnknownType ||
-                     (type >= (int)QVariant::UserType && !(flags & QMetaType::PointerToQObject) &&
-                      type != qMetaTypeId<QJSValue>())) {
-                //the UserType clause is to catch registered QFlags)
-                if (argTypeNames.isEmpty())
-                    argTypeNames = m.parameterTypes();
-                type = EnumType(_m.asT2(), argTypeNames.at(ii), type);
-            }
-            if (type == QMetaType::UnknownType) {
-                if (unknownTypeError) *unknownTypeError = argTypeNames.at(ii);
-                return 0;
-            }
-            dummy[ii + 1] = type;
-        }
+    }
+}
 
-        return dummy.data();
+int* QQmlMetaObject::methodParameterTypes(const QMetaMethod &m, QVarLengthArray<int, 9> &dummy, QByteArray *unknownTypeError) const {
+    int argc = m.parameterCount();
+    dummy.resize(argc + 1);
+    dummy[0] = argc;
+    QList<QByteArray> argTypeNames; // Only loaded if needed
+
+    for (int ii = 0; ii < argc; ++ii) {
+        int type = m.parameterType(ii);
+        QMetaType::TypeFlags flags = QMetaType::typeFlags(type);
+        if (flags & QMetaType::IsEnumeration)
+            type = QVariant::Int;
+        else if (type == QMetaType::UnknownType ||
+                 (type >= (int)QVariant::UserType && !(flags & QMetaType::PointerToQObject) &&
+                  type != qMetaTypeId<QJSValue>())) {
+            //the UserType clause is to catch registered QFlags)
+            if (argTypeNames.isEmpty())
+                argTypeNames = m.parameterTypes();
+            type = EnumType(_m.asT2(), argTypeNames.at(ii), type);
+        }
+        if (type == QMetaType::UnknownType) {
+            if (unknownTypeError) *unknownTypeError = argTypeNames.at(ii);
+            return 0;
+        }
+        dummy[ii + 1] = type;
     }
+
+    return dummy.data();
 }
 
 void QQmlObjectOrGadget::metacall(QMetaObject::Call type, int index, void **argv) const
 {
-    if (ptr.isT1())
+    if (ptr.isNull()) {
+        const QMetaObject *metaObject = _m.asT2();
+        metaObject->d.static_metacall(0, type, index, argv);
+    }
+    else if (ptr.isT1()) {
         QMetaObject::metacall(ptr.asT1(), type, index, argv);
+    }
     else {
         const QMetaObject *metaObject = _m.asT1()->metaObject();
         QQmlMetaObject::resolveGadgetMethodOrPropertyIndex(type, &metaObject, &index);
@@ -1548,4 +1568,9 @@ void QQmlObjectOrGadget::metacall(QMetaObject::Call type, int index, void **argv
     }
 }
 
+int* QQmlStaticMetaObject::constructorParameterTypes(int index, QVarLengthArray<int, 9> &dummy, QByteArray *unknownTypeError) const {
+    QMetaMethod m = _m.asT2()->constructor(index);
+    return methodParameterTypes(m, dummy, unknownTypeError);
+}
+
 QT_END_NAMESPACE
diff --git a/src/qml/qml/qqmlpropertycache_p.h b/src/qml/qml/qqmlpropertycache_p.h
index b2171dd86b..3e84fb3070 100644
--- a/src/qml/qml/qqmlpropertycache_p.h
+++ b/src/qml/qml/qqmlpropertycache_p.h
@@ -115,9 +115,10 @@ public:
         IsSignalHandler    = 0x00800000, // Function is a signal handler
         IsOverload         = 0x01000000, // Function is an overload of another function
         IsCloned           = 0x02000000, // The function was marked as cloned
+        IsConstructor      = 0x04000000, // The function was marked is a constructor
 
         // Internal QQmlPropertyCache flags
-        NotFullyResolved   = 0x04000000, // True if the type data is to be lazily resolved
+        NotFullyResolved   = 0x08000000, // True if the type data is to be lazily resolved
 
         // Flags that are set based on the propType field
         PropTypeFlagMask = IsQObjectDerived | IsEnumType | IsQList | IsQmlBinding | IsQJSValue |
@@ -156,6 +157,7 @@ public:
     bool isSignalHandler() const { return flags & IsSignalHandler; }
     bool isOverload() const { return flags & IsOverload; }
     bool isCloned() const { return flags & IsCloned; }
+    bool isConstructor() const { return flags & IsConstructor; }
 
     bool hasOverride() const { return !(flags & IsValueTypeVirtual) &&
                                       !(flags & HasAccessors) &&
@@ -437,6 +439,8 @@ public:
 
 protected:
     QBiPointer<QQmlPropertyCache, const QMetaObject> _m;
+    int *methodParameterTypes(const QMetaMethod &method, QVarLengthArray<int, 9> &dummy, QByteArray *unknownTypeError) const;
+
 };
 
 class QQmlObjectOrGadget: public QQmlMetaObject
@@ -455,6 +459,20 @@ public:
 
 private:
     QBiPointer<QObject, void> ptr;
+
+protected:
+    QQmlObjectOrGadget(const QMetaObject* metaObject)
+        : QQmlMetaObject(metaObject)
+    {}
+
+};
+
+class QQmlStaticMetaObject : public QQmlObjectOrGadget {
+public:
+    QQmlStaticMetaObject(const QMetaObject* metaObject)
+        : QQmlObjectOrGadget(metaObject)
+    {}
+    int *constructorParameterTypes(int index, QVarLengthArray<int, 9> &dummy, QByteArray *unknownTypeError) const;
 };
 
 QQmlPropertyData::QQmlPropertyData()