Make the default constructor of PersistentValue not allocate a d pointer

This is also required to change the v8::Persistent in QQmlData over
to v4.

Change-Id: Ib3164ded9c772e977f6b43ef6163a3aa74da3800
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

11 files changed, 41 insertions, 39 deletions

diff --git a/src/qml/qml/qqmlbinding.cpp b/src/qml/qml/qqmlbinding.cpp
index 9e1a1522af..b66f053b0f 100644
--- a/src/qml/qml/qqmlbinding.cpp
+++ b/src/qml/qml/qqmlbinding.cpp
@@ -279,7 +279,7 @@ void QQmlBinding::update(QQmlPropertyPrivate::WriteFlags flags)
             bool isUndefined = false;
 
             v8::Handle<v8::Value> result =
-                QQmlJavaScriptExpression::evaluate(context(), **v4function, &isUndefined);
+                    QQmlJavaScriptExpression::evaluate(context(), v4function.value(), &isUndefined);
 
             trace.event("writing binding result");
 
@@ -320,7 +320,7 @@ QVariant QQmlBinding::evaluate()
     bool isUndefined = false;
 
     v8::Handle<v8::Value> result =
-        QQmlJavaScriptExpression::evaluate(context(), **v4function, &isUndefined);
+            QQmlJavaScriptExpression::evaluate(context(), v4function.value(), &isUndefined);
 
     ep->dereferenceScarceResources();
 
diff --git a/src/qml/qml/qqmlboundsignal.cpp b/src/qml/qml/qqmlboundsignal.cpp
index d84d7a492d..acb79032e7 100644
--- a/src/qml/qml/qqmlboundsignal.cpp
+++ b/src/qml/qml/qqmlboundsignal.cpp
@@ -138,7 +138,7 @@ QString QQmlBoundSignalExpression::expression() const
 {
     if (m_expressionFunctionValid) {
         Q_ASSERT (context() && engine());
-        return m_v8function->toQString();
+        return m_v8function.value().toQString();
     } else if (!m_expressionUtf8.isEmpty()) {
         return QString::fromUtf8(m_expressionUtf8);
     } else {
@@ -206,7 +206,7 @@ void QQmlBoundSignalExpression::evaluate(void **a)
                                             m_fileName, m_line, &m_v8qmlscope);
             }
 
-            if (m_v8function->isEmpty() || m_v8function->isNull()) {
+            if (m_v8function.isEmpty() || m_v8function.value().isNull()) {
                 ep->dereferenceScarceResources();
                 return; // could not evaluate function.  Not valid.
             }
@@ -216,7 +216,7 @@ void QQmlBoundSignalExpression::evaluate(void **a)
         }
 
         if (!hasParameterInfo()) {
-            QQmlJavaScriptExpression::evaluate(context(), **m_v8function, 0);
+            QQmlJavaScriptExpression::evaluate(context(), m_v8function.value(), 0);
         } else {
             QV8Engine *engine = ep->v8engine();
             QVarLengthArray<int, 9> dummy;
@@ -249,7 +249,7 @@ void QQmlBoundSignalExpression::evaluate(void **a)
                 }
             }
 
-            QQmlJavaScriptExpression::evaluate(context(), **m_v8function, argCount, args.data(), 0);
+            QQmlJavaScriptExpression::evaluate(context(), m_v8function.value(), argCount, args.data(), 0);
         }
     }
     ep->dereferenceScarceResources(); // "release" scarce resources if top-level expression evaluation is complete.
diff --git a/src/qml/qml/qqmlexpression.cpp b/src/qml/qml/qqmlexpression.cpp
index 0f225228b3..32dbbb0e6c 100644
--- a/src/qml/qml/qqmlexpression.cpp
+++ b/src/qml/qml/qqmlexpression.cpp
@@ -354,7 +354,7 @@ v8::Handle<v8::Value> QQmlExpressionPrivate::v8value(bool *isUndefined)
         expressionFunctionValid = true;
     }
 
-    return evaluate(context(), **v8function, isUndefined);
+    return evaluate(context(), v8function.value(), isUndefined);
 }
 
 QVariant QQmlExpressionPrivate::value(bool *isUndefined)
diff --git a/src/qml/qml/qqmlpropertycache.cpp b/src/qml/qml/qqmlpropertycache.cpp
index df3d558cb4..bcfc901c53 100644
--- a/src/qml/qml/qqmlpropertycache.cpp
+++ b/src/qml/qml/qqmlpropertycache.cpp
@@ -290,8 +290,8 @@ QQmlPropertyCache::~QQmlPropertyCache()
 
 void QQmlPropertyCache::destroy()
 {
-    Q_ASSERT(engine || constructor->isEmpty());
-    if (constructor->isEmpty())
+    Q_ASSERT(engine || constructor.isEmpty());
+    if (constructor.isEmpty())
         delete this;
     else
         QQmlEnginePrivate::deleteInEngineThread(engine, this);
@@ -598,7 +598,7 @@ void QQmlPropertyCache::append(QQmlEngine *engine, const QMetaObject *metaObject
                                        QQmlPropertyData::Flag signalFlags)
 {
     Q_UNUSED(revision);
-    Q_ASSERT(constructor->isEmpty()); // We should not be appending to an in-use property cache
+    Q_ASSERT(constructor.isEmpty()); // We should not be appending to an in-use property cache
 
     _metaObject = metaObject;
 
diff --git a/src/qml/qml/qqmlvmemetaobject.cpp b/src/qml/qml/qqmlvmemetaobject.cpp
index 37adaad57a..0f808db9a5 100644
--- a/src/qml/qml/qqmlvmemetaobject.cpp
+++ b/src/qml/qml/qqmlvmemetaobject.cpp
@@ -972,7 +972,7 @@ v8::Handle<v8::Function> QQmlVMEMetaObject::method(int index)
     if (!v8methods) 
         v8methods = new QV4::PersistentValue[metaData->methodCount];
 
-    if (v8methods[index]->isEmpty()) {
+    if (v8methods[index].isEmpty()) {
         QQmlVMEMetaData::MethodData *data = metaData->methodData() + index;
 
         const char *body = ((const char*)metaData) + data->bodyOffset;
diff --git a/src/qml/qml/v4/qv4value.cpp b/src/qml/qml/v4/qv4value.cpp
index f330aebad9..af57c47b90 100644
--- a/src/qml/qml/v4/qv4value.cpp
+++ b/src/qml/qml/v4/qv4value.cpp
@@ -217,11 +217,6 @@ Value Value::property(ExecutionContext *ctx, String *name) const
 }
 
 
-PersistentValue::PersistentValue()
-    : d(new PersistentValuePrivate)
-{
-}
-
 PersistentValue::PersistentValue(const Value &val)
     : d(new PersistentValuePrivate(val))
 {
@@ -230,7 +225,8 @@ PersistentValue::PersistentValue(const Value &val)
 PersistentValue::PersistentValue(const PersistentValue &other)
     : d(other.d)
 {
-    d->ref();
+    if (d)
+        d->ref();
 }
 
 PersistentValue &PersistentValue::operator=(const PersistentValue &other)
@@ -239,13 +235,20 @@ PersistentValue &PersistentValue::operator=(const PersistentValue &other)
         return *this;
 
     // the memory manager cleans up those with a refcount of 0
-    d->deref();
+
+    if (d)
+        d->deref();
     d = other.d;
-    d->ref();
+    if (d)
+        d->ref();
 }
 
 PersistentValue &PersistentValue::operator =(const Value &other)
 {
+    if (!d) {
+        d = new PersistentValuePrivate(other);
+        return *this;
+    }
     d->value = other;
     if (!d->prev) {
         if (Managed *m = d->value.asManaged()) {
@@ -261,7 +264,8 @@ PersistentValue &PersistentValue::operator =(const Value &other)
 
 PersistentValue::~PersistentValue()
 {
-    d->deref();
+    if (d)
+        d->deref();
 }
 
 PersistentValuePrivate::PersistentValuePrivate(const Value &v)
@@ -287,7 +291,8 @@ void PersistentValuePrivate::deref()
     // and will get cleaned up in the next gc run
     if (!--refcount) {
         if (prev) {
-            next->prev = prev;
+            if (next)
+                next->prev = prev;
             *prev = next;
         }
         delete this;
diff --git a/src/qml/qml/v4/qv4value_p.h b/src/qml/qml/v4/qv4value_p.h
index 1d2285cbc7..5b56c910e5 100644
--- a/src/qml/qml/v4/qv4value_p.h
+++ b/src/qml/qml/v4/qv4value_p.h
@@ -551,12 +551,6 @@ inline Value Managed::call(ExecutionContext *context, const Value &thisObject, V
 
 struct PersistentValuePrivate
 {
-    PersistentValuePrivate()
-        : value(Value::emptyValue())
-        , refcount(1)
-        , prev(0)
-        , next(0)
-    {}
     PersistentValuePrivate(const Value &v);
     Value value;
     int refcount;
@@ -570,24 +564,27 @@ struct PersistentValuePrivate
 class PersistentValue
 {
 public:
-    PersistentValue();
+    PersistentValue() : d(0) {}
     PersistentValue(const Value &val);
     PersistentValue(const PersistentValue &other);
     PersistentValue &operator=(const PersistentValue &other);
     PersistentValue &operator=(const Value &other);
     ~PersistentValue();
 
-    Value *operator->() { return &d->value; }
-    Value *operator*() { return &d->value; }
-    const Value *operator->() const { return &d->value; }
-    const Value *operator*() const { return &d->value; }
+    Value value() const {
+        return d ? d->value : Value::emptyValue();
+    }
 
     ExecutionEngine *engine() {
+        if (!d)
+            return 0;
         Managed *m = d->value.asManaged();
         return m ? m->engine() : 0;
     }
 
-    operator Value() const { return d->value; }
+    operator Value() const { return value(); }
+
+    bool isEmpty() const { return !d; }
 
 private:
     PersistentValuePrivate *d;
diff --git a/src/qml/qml/v8/qjsvalue_p.h b/src/qml/qml/v8/qjsvalue_p.h
index ab8572baf9..db30ad8c92 100644
--- a/src/qml/qml/v8/qjsvalue_p.h
+++ b/src/qml/qml/v8/qjsvalue_p.h
@@ -80,7 +80,7 @@ public:
         : PersistentValuePrivate(QV4::Value::fromString(s))
     {}
     QJSValuePrivate(const QString &s)
-        : PersistentValuePrivate()
+        : PersistentValuePrivate(QV4::Value::undefinedValue())
         , string(0, s)
     {
         value = QV4::Value::fromString(&string);
diff --git a/src/qml/qml/v8/qv8bindings.cpp b/src/qml/qml/v8/qv8bindings.cpp
index a17f2a732a..f437984ec6 100644
--- a/src/qml/qml/v8/qv8bindings.cpp
+++ b/src/qml/qml/v8/qv8bindings.cpp
@@ -245,7 +245,7 @@ QV8Bindings::QV8Bindings(QQmlCompiledData::V8Program *program,
 {
     QV8Engine *engine = QQmlEnginePrivate::getV8Engine(context->engine);
 
-    if (program->bindings->isEmpty()) {
+    if (program->bindings.isEmpty()) {
         v8::Handle<v8::Script> script;
         bool compileFailed = false;
         {
@@ -327,7 +327,7 @@ const QString &QV8Bindings::urlString() const
 
 QV4::ArrayObject *QV8Bindings::functions() const
 {
-    return program->bindings->asArrayObject();
+    return program->bindings.value().asArrayObject();
 }
 
 
diff --git a/src/qml/qml/v8/qv8engine.cpp b/src/qml/qml/v8/qv8engine.cpp
index 4a6300c256..6dc3ac714b 100644
--- a/src/qml/qml/v8/qv8engine.cpp
+++ b/src/qml/qml/v8/qv8engine.cpp
@@ -688,7 +688,7 @@ void QV8Engine::initializeGlobal(v8::Handle<v8::Object> global)
 void QV8Engine::freezeObject(const QV4::Value &value)
 {
     QV4::Value args = value;
-    m_freezeObject->asFunctionObject()->call(m_v4Engine->rootContext, QV4::Value::fromObject(m_v4Engine->globalObject), &args, 1);
+    m_freezeObject.value().asFunctionObject()->call(m_v4Engine->rootContext, QV4::Value::fromObject(m_v4Engine->globalObject), &args, 1);
 }
 
 void QV8Engine::gc()
diff --git a/src/qml/qml/v8/qv8qobjectwrapper.cpp b/src/qml/qml/v8/qv8qobjectwrapper.cpp
index e25b8b478b..86ae6a165a 100644
--- a/src/qml/qml/v8/qv8qobjectwrapper.cpp
+++ b/src/qml/qml/v8/qv8qobjectwrapper.cpp
@@ -961,7 +961,7 @@ v8::Handle<v8::Object> QQmlPropertyCache::newQObject(QObject *object, QV8Engine
     Q_ASSERT(QQmlData::get(object, false)->propertyCache == this);
 
     // Setup constructor
-    if (constructor->isEmpty()) {
+    if (constructor.isEmpty()) {
         v8::Handle<v8::FunctionTemplate> ft;
 
         const QHashedString toString(QStringLiteral("toString"));
@@ -1050,7 +1050,7 @@ v8::Handle<v8::Object> QQmlPropertyCache::newQObject(QObject *object, QV8Engine
         QQmlCleanup::addToEngine(this->engine);
     }
 
-    v8::Handle<v8::Object> result = constructor->asFunctionObject()->newInstance();
+    v8::Handle<v8::Object> result = constructor.value().asFunctionObject()->newInstance();
     QV8QObjectResource *r = new QV8QObjectResource(engine, object);
     result->SetExternalResource(r);
     return result;