Fix QQmlV4Function API to be GC safe

Change-Id: Id4f79c22fc48ada1c8a9a858e1b7b3d1cf14d120
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

6 files changed, 82 insertions, 67 deletions

diff --git a/src/quick/items/context2d/qquickcanvasitem.cpp b/src/quick/items/context2d/qquickcanvasitem.cpp
index 50a5431740..94fe95da4e 100644
--- a/src/quick/items/context2d/qquickcanvasitem.cpp
+++ b/src/quick/items/context2d/qquickcanvasitem.cpp
@@ -739,35 +739,37 @@ void QQuickCanvasItem::getContext(QQmlV4Function *args)
 {
     Q_D(QQuickCanvasItem);
 
-    if (args->length() < 1 || !(*args)[0].isString()) {
+    QV4::Scope scope(args->v4engine());
+    QV4::ScopedString str(scope, (*args)[0]);
+    if (!str) {
         qmlInfo(this) << "getContext should be called with a string naming the required context type";
-        args->setReturnValue(QV4::Value::nullValue());
+        args->setReturnValue(QV4::Encode::null());
         return;
     }
 
     if (!d->available) {
         qmlInfo(this) << "Unable to use getContext() at this time, please wait for available: true";
-        args->setReturnValue(QV4::Value::nullValue());
+        args->setReturnValue(QV4::Encode::null());
         return;
     }
 
-    QString contextId = (*args)[0].toQStringNoThrow();
+    QString contextId = str->toQString();
 
     if (d->context != 0) {
         if (d->context->contextNames().contains(contextId, Qt::CaseInsensitive)) {
-            args->setReturnValue(QV4::Value::fromReturnedValue(d->context->v4value()));
+            args->setReturnValue(d->context->v4value());
             return;
         }
 
         qmlInfo(this) << "Canvas already initialized with a different context type";
-        args->setReturnValue(QV4::Value::nullValue());
+        args->setReturnValue(QV4::Encode::null());
         return;
     }
 
     if (createContext(contextId))
-        args->setReturnValue(QV4::Value::fromReturnedValue(d->context->v4value()));
+        args->setReturnValue(d->context->v4value());
     else
-        args->setReturnValue(QV4::Value::nullValue());
+        args->setReturnValue(QV4::Encode::null());
 }
 
 /*!
@@ -779,9 +781,11 @@ void QQuickCanvasItem::getContext(QQmlV4Function *args)
 
 void QQuickCanvasItem::requestAnimationFrame(QQmlV4Function *args)
 {
-    if (args->length() < 1 || !(*args)[0].asFunctionObject()) {
+    QV4::Scope scope(args->v4engine());
+    QV4::ScopedFunctionObject f(scope, (*args)[0]);
+    if (!f) {
         qmlInfo(this) << "requestAnimationFrame should be called with an animation callback function";
-        args->setReturnValue(QV4::Value::nullValue());
+        args->setReturnValue(QV4::Encode::null());
         return;
     }
 
@@ -789,14 +793,12 @@ void QQuickCanvasItem::requestAnimationFrame(QQmlV4Function *args)
 
     static int id = 0;
 
-    QV4::Scope scope(QV8Engine::getV4(args->engine()));
-    QV4::ScopedValue v(scope, (*args)[0]);
-    d->animationCallbacks.insert(++id, QV4::PersistentValue(v));
+    d->animationCallbacks.insert(++id, QV4::PersistentValue(f));
 
     if (isVisible())
         polish();
 
-    args->setReturnValue(QV4::Value::fromInt32(id));
+    args->setReturnValue(QV4::Encode(id));
 }
 
 /*!
@@ -807,13 +809,15 @@ void QQuickCanvasItem::requestAnimationFrame(QQmlV4Function *args)
 
 void QQuickCanvasItem::cancelRequestAnimationFrame(QQmlV4Function *args)
 {
-    if (args->length() < 1 || !(*args)[0].isInteger()) {
+    QV4::Scope scope(args->v4engine());
+    QV4::ScopedValue v(scope, (*args)[0]);
+    if (!v->isInteger()) {
         qmlInfo(this) << "cancelRequestAnimationFrame should be called with an animation callback id";
-        args->setReturnValue(QV4::Value::nullValue());
+        args->setReturnValue(QV4::Encode::null());
         return;
     }
 
-    d_func()->animationCallbacks.remove((*args)[0].integerValue());
+    d_func()->animationCallbacks.remove(v->integerValue());
 }
 
 
diff --git a/src/quick/items/qquickdrag.cpp b/src/quick/items/qquickdrag.cpp
index d66c57c667..fa8b52dfd9 100644
--- a/src/quick/items/qquickdrag.cpp
+++ b/src/quick/items/qquickdrag.cpp
@@ -595,9 +595,10 @@ void QQuickDragAttached::start(QQmlV4Function *args)
     Qt::DropActions supportedActions = d->supportedActions;
     // check arguments for supportedActions, maybe data?
     if (args->length() >= 1) {
-        QV4::Value v = (*args)[0];
-        if (v.isInt32()) {
-            supportedActions = Qt::DropActions(v.integerValue());
+        QV4::Scope scope(args->v4engine());
+        QV4::ScopedValue v(scope, (*args)[0]);
+        if (v->isInt32()) {
+            supportedActions = Qt::DropActions(v->integerValue());
             d->overrideActions = true;
         }
     }
@@ -773,15 +774,16 @@ void QQuickDragAttached::startDrag(QQmlV4Function *args)
 
     // check arguments for supportedActions
     if (args->length() >= 1) {
-        QV4::Value v = (*args)[0];
-        if (v.isInt32()) {
-            supportedActions = Qt::DropActions(v.integerValue());
+        QV4::Scope scope(args->v4engine());
+        QV4::ScopedValue v(scope, (*args)[0]);
+        if (v->isInt32()) {
+            supportedActions = Qt::DropActions(v->integerValue());
         }
     }
 
     Qt::DropAction dropAction = d->startDrag(supportedActions);
 
-    args->setReturnValue(QV4::Value::fromInt32(dropAction));
+    args->setReturnValue(QV4::Encode((int)dropAction));
 }
 
 QQuickDrag::QQuickDrag(QObject *parent)
diff --git a/src/quick/items/qquickdroparea.cpp b/src/quick/items/qquickdroparea.cpp
index 51037508e0..92275b1655 100644
--- a/src/quick/items/qquickdroparea.cpp
+++ b/src/quick/items/qquickdroparea.cpp
@@ -559,11 +559,12 @@ QStringList QQuickDropEvent::formats() const
 void QQuickDropEvent::getDataAsString(QQmlV4Function *args)
 {
     if (args->length() != 0) {
-        QV4::Value v = (*args)[0];
-        QString format = v.toQString();
+        QV4::ExecutionEngine *v4 = args->v4engine();
+        QV4::Scope scope(v4);
+        QV4::ScopedValue v(scope, (*args)[0]);
+        QString format = v->toQString();
         QString rv = QString::fromUtf8(event->mimeData()->data(format));
-        QV4::ExecutionEngine *v4 = QV8Engine::getV4(args->engine());
-        args->setReturnValue(QV4::Value::fromString(v4, rv));
+        args->setReturnValue(QV4::Value::fromString(v4, rv).asReturnedValue());
     }
 }
 
@@ -577,9 +578,10 @@ void QQuickDropEvent::accept(QQmlV4Function *args)
     Qt::DropAction action = event->dropAction();
 
     if (args->length() >= 1) {
-        QV4::Value v = (*args)[0];
-        if (v.isInt32())
-            action = Qt::DropAction(v.integerValue());
+        QV4::Scope scope(args->v4engine());
+        QV4::ScopedValue v(scope, (*args)[0]);
+        if (v->isInt32())
+            action = Qt::DropAction(v->integerValue());
     }
 
     // get action from arguments.
diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index 3ecd5f558d..cd9e88e452 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -3868,34 +3868,35 @@ void QQuickItem::polish()
 void QQuickItem::mapFromItem(QQmlV4Function *args) const
 {
     if (args->length() != 0) {
-        QV4::Value item = (*args)[0];
+        QV4::ExecutionEngine *v4 = args->v4engine();
+        QV4::Scope scope(v4);
+        QV4::ScopedValue item(scope, (*args)[0]);
 
         QQuickItem *itemObj = 0;
-        if (!item.isNull()) {
-            if (QV4::QObjectWrapper *qobjectWrapper = item.as<QV4::QObjectWrapper>())
+        if (!item->isNull()) {
+            QV4::Scoped<QV4::QObjectWrapper> qobjectWrapper(scope, item->as<QV4::QObjectWrapper>());
+            if (qobjectWrapper)
                 itemObj = qobject_cast<QQuickItem*>(qobjectWrapper->object());
         }
 
-        if (!itemObj && !item.isNull()) {
-            qmlInfo(this) << "mapFromItem() given argument \"" << item.toQStringNoThrow()
+        if (!itemObj && !item->isNull()) {
+            qmlInfo(this) << "mapFromItem() given argument \"" << item->toQStringNoThrow()
                           << "\" which is neither null nor an Item";
             return;
         }
 
-        QV4::ExecutionEngine *v4 = QV8Engine::getV4(args->engine());
-        QV4::Scope scope(v4);
         QV4::Scoped<QV4::Object> rv(scope, v4->newObject());
-        args->setReturnValue(rv.asValue());
+        args->setReturnValue(rv.asReturnedValue());
 
         QV4::ScopedString s(scope);
         QV4::ScopedValue v(scope);
 
-        qreal x = (args->length() > 1) ? (*args)[1].asDouble() : 0;
-        qreal y = (args->length() > 2) ? (*args)[2].asDouble() : 0;
+        qreal x = (args->length() > 1) ? (v = (*args)[1])->asDouble() : 0;
+        qreal y = (args->length() > 2) ? (v = (*args)[2])->asDouble() : 0;
 
         if (args->length() > 3) {
-            qreal w = (*args)[3].asDouble();
-            qreal h = (args->length() > 4) ? (*args)[4].asDouble() : 0;
+            qreal w = (v = (*args)[3])->asDouble();
+            qreal h = (args->length() > 4) ? (v = (*args)[4])->asDouble() : 0;
 
             QRectF r = mapRectFromItem(itemObj, QRectF(x, y, w, h));
 
@@ -3946,34 +3947,36 @@ QTransform QQuickItem::itemTransform(QQuickItem *other, bool *ok) const
 void QQuickItem::mapToItem(QQmlV4Function *args) const
 {
     if (args->length() != 0) {
-        QV4::Value item = (*args)[0];
+        QV4::ExecutionEngine *v4 = args->v4engine();
+        QV4::Scope scope(v4);
+        QV4::ScopedValue item(scope, (*args)[0]);
 
         QQuickItem *itemObj = 0;
-        if (!item.isNull()) {
-            if (QV4::QObjectWrapper *qobjectWrapper = item.as<QV4::QObjectWrapper>())
+        if (!item->isNull()) {
+            QV4::Scoped<QV4::QObjectWrapper> qobjectWrapper(scope, item->as<QV4::QObjectWrapper>());
+            if (qobjectWrapper)
                 itemObj = qobject_cast<QQuickItem*>(qobjectWrapper->object());
         }
 
-        if (!itemObj && !item.isNull()) {
-            qmlInfo(this) << "mapToItem() given argument \"" << item.toQStringNoThrow()
+        if (!itemObj && !item->isNull()) {
+            qmlInfo(this) << "mapToItem() given argument \"" << item->toQStringNoThrow()
                           << "\" which is neither null nor an Item";
             return;
         }
 
-        QV4::ExecutionEngine *v4 = QV8Engine::getV4(args->engine());
-        QV4::Scope scope(v4);
         QV4::Scoped<QV4::Object> rv(scope, v4->newObject());
-        args->setReturnValue(rv.asValue());
+        args->setReturnValue(rv.asReturnedValue());
 
-        qreal x = (args->length() > 1) ? (*args)[1].asDouble() : 0;
-        qreal y = (args->length() > 2) ? (*args)[2].asDouble() : 0;
+        QV4::ScopedValue v(scope);
+
+        qreal x = (args->length() > 1) ? (v = (*args)[1])->asDouble() : 0;
+        qreal y = (args->length() > 2) ? (v = (*args)[2])->asDouble() : 0;
 
         QV4::ScopedString s(scope);
-        QV4::ScopedValue v(scope);
 
         if (args->length() > 3) {
-            qreal w = (*args)[3].asDouble();
-            qreal h = (args->length() > 4) ? (*args)[4].asDouble() : 0;
+            qreal w = (v = (*args)[3])->asDouble();
+            qreal h = (args->length() > 4) ? (v = (*args)[4])->asDouble() : 0;
 
             QRectF r = mapRectToItem(itemObj, QRectF(x, y, w, h));
 
diff --git a/src/quick/items/qquickloader.cpp b/src/quick/items/qquickloader.cpp
index 63490ef2cc..1301225feb 100644
--- a/src/quick/items/qquickloader.cpp
+++ b/src/quick/items/qquickloader.cpp
@@ -568,7 +568,7 @@ void QQuickLoader::setSource(QQmlV4Function *args)
     Q_D(QQuickLoader);
 
     bool ipvError = false;
-    args->setReturnValue(QV4::Value::undefinedValue());
+    args->setReturnValue(QV4::Encode::undefined());
     QV4::Value ipv = d->extractInitialPropertyValues(args, this, &ipvError);
     if (ipvError)
         return;
@@ -578,7 +578,7 @@ void QQuickLoader::setSource(QQmlV4Function *args)
     if (!ipv.isUndefined()) {
         d->disposeInitialPropertyValues();
         d->initialPropertyValues = ipv.asReturnedValue();
-        d->qmlGlobalForIpv = args->qmlGlobal().asReturnedValue();
+        d->qmlGlobalForIpv = args->qmlGlobal();
     }
 
     setSource(sourceUrl, false); // already cleared and set ipv above.
@@ -926,7 +926,9 @@ void QQuickLoader::geometryChanged(const QRectF &newGeometry, const QRectF &oldG
 
 QUrl QQuickLoaderPrivate::resolveSourceUrl(QQmlV4Function *args)
 {
-    QString arg = (*args)[0].toQStringNoThrow();
+    QV4::Scope scope(args->v4engine());
+    QV4::ScopedValue v(scope, (*args)[0]);
+    QString arg = v->toQString();
     if (arg.isEmpty())
         return QUrl();
 
@@ -937,10 +939,11 @@ QUrl QQuickLoaderPrivate::resolveSourceUrl(QQmlV4Function *args)
 
 QV4::Value QQuickLoaderPrivate::extractInitialPropertyValues(QQmlV4Function *args, QObject *loader, bool *error)
 {
-    QV4::Value valuemap = QV4::Value::undefinedValue();
+    QV4::Scope scope(args->v4engine());
+    QV4::ScopedValue valuemap(scope, QV4::Value::undefinedValue());
     if (args->length() >= 2) {
-        QV4::Value v = (*args)[1];
-        if (!v.isObject() || v.asArrayObject()) {
+        QV4::ScopedValue v(scope, (*args)[1]);
+        if (!v->isObject() || v->asArrayObject()) {
             *error = true;
             qmlInfo(loader) << QQuickLoader::tr("setSource: value is not an object");
         } else {
diff --git a/src/quick/items/qquicktextinput.cpp b/src/quick/items/qquicktextinput.cpp
index b5b86993f4..a5db64c983 100644
--- a/src/quick/items/qquicktextinput.cpp
+++ b/src/quick/items/qquicktextinput.cpp
@@ -1420,17 +1420,18 @@ void QQuickTextInput::positionAt(QQmlV4Function *args) const
         return;
 
     int i = 0;
-    QV4::Value arg = (*args)[i];
-    x = arg.toNumber();
+    QV4::Scope scope(args->v4engine());
+    QV4::ScopedValue arg(scope, (*args)[0]);
+    x = arg->toNumber();
 
     if (++i < args->length()) {
         arg = (*args)[i];
-        y = arg.toNumber();
+        y = arg->toNumber();
     }
 
     if (++i < args->length()) {
         arg = (*args)[i];
-        position = QTextLine::CursorPosition(arg.toInt32());
+        position = QTextLine::CursorPosition(arg->toInt32());
     }
 
     int pos = d->positionAt(x, y, position);
@@ -1445,7 +1446,7 @@ void QQuickTextInput::positionAt(QQmlV4Function *args) const
         pos = cursor;
 #endif
     }
-    args->setReturnValue(QV4::Value::fromInt32(pos));
+    args->setReturnValue(QV4::Encode(pos));
 }
 
 int QQuickTextInputPrivate::positionAt(qreal x, qreal y, QTextLine::CursorPosition position) const