Split responsibilities in QDeclarativeExpression more cleanly

7 files changed, 401 insertions, 331 deletions

diff --git a/src/declarative/qml/qdeclarativebinding.cpp b/src/declarative/qml/qdeclarativebinding.cpp
index 882e981..e3b33c0 100644
--- a/src/declarative/qml/qdeclarativebinding.cpp
+++ b/src/declarative/qml/qdeclarativebinding.cpp
@@ -54,27 +54,20 @@
 
 QT_BEGIN_NAMESPACE
 
-QDeclarativeBindingData::QDeclarativeBindingData()
-: updating(false), enabled(false)
+void QDeclarativeBindingPrivate::refresh()
 {
+    Q_Q(QDeclarativeBinding);
+    q->update();
 }
 
-QDeclarativeBindingData::~QDeclarativeBindingData()
-{
-    removeError();
-}
-
-void QDeclarativeBindingData::refresh()
+QDeclarativeBindingPrivate::QDeclarativeBindingPrivate()
+: updating(false), enabled(false), deleted(0)
 {
-    if (enabled && !updating && q) {
-        QDeclarativeBinding *b = static_cast<QDeclarativeBinding *>(QDeclarativeExpressionPrivate::get(q));
-        b->update();
-    }
 }
 
-QDeclarativeBindingPrivate::QDeclarativeBindingPrivate()
-: QDeclarativeExpressionPrivate(new QDeclarativeBindingData)
+QDeclarativeBindingPrivate::~QDeclarativeBindingPrivate()
 {
+    if (deleted) *deleted = true;
 }
 
 QDeclarativeBinding::QDeclarativeBinding(void *data, QDeclarativeRefCount *rc, QObject *obj, 
@@ -109,7 +102,7 @@ QDeclarativeBinding::~QDeclarativeBinding()
 void QDeclarativeBinding::setTarget(const QDeclarativeProperty &prop)
 {
     Q_D(QDeclarativeBinding);
-    d->bindingData()->property = prop;
+    d->property = prop;
 
     update();
 }
@@ -117,50 +110,53 @@ void QDeclarativeBinding::setTarget(const QDeclarativeProperty &prop)
 QDeclarativeProperty QDeclarativeBinding::property() const 
 {
    Q_D(const QDeclarativeBinding);
-   return d->bindingData()->property; 
+   return d->property; 
 }
 
 void QDeclarativeBinding::update(QDeclarativePropertyPrivate::WriteFlags flags)
 {
     Q_D(QDeclarativeBinding);
 
-    QDeclarativeBindingData *data = d->bindingData();
-
-    if (!data->enabled || !data->context() || !data->context()->isValid())
+    if (!d->enabled || !d->context() || !d->context()->isValid()) 
         return;
 
-    data->addref();
+    if (!d->updating) {
+        d->updating = true;
+        bool wasDeleted = false;
+        d->deleted = &wasDeleted;
 
-    if (!data->updating) {
-        data->updating = true;
+        if (d->property.propertyType() == qMetaTypeId<QDeclarativeBinding *>()) {
 
-        if (data->property.propertyType() == qMetaTypeId<QDeclarativeBinding *>()) {
-
-            int idx = data->property.index();
+            int idx = d->property.index();
             Q_ASSERT(idx != -1);
 
-
             QDeclarativeBinding *t = this;
             int status = -1;
             void *a[] = { &t, 0, &status, &flags };
-            QMetaObject::metacall(data->property.object(),
+            QMetaObject::metacall(d->property.object(),
                                   QMetaObject::WriteProperty,
                                   idx, a);
 
+            if (wasDeleted)
+                return;
+
         } else {
-            QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(data->context()->engine);
+            QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(d->context()->engine);
 
             bool isUndefined = false;
             QVariant value;
 
             QScriptValue scriptValue = d->scriptValue(0, &isUndefined);
-            if (data->property.propertyTypeCategory() == QDeclarativeProperty::List) {
+            if (wasDeleted)
+                return;
+
+            if (d->property.propertyTypeCategory() == QDeclarativeProperty::List) {
                 value = ep->scriptValueToVariant(scriptValue, qMetaTypeId<QList<QObject *> >());
             } else if (scriptValue.isNull() && 
-                       data->property.propertyTypeCategory() == QDeclarativeProperty::Object) {
+                       d->property.propertyTypeCategory() == QDeclarativeProperty::Object) {
                 value = QVariant::fromValue((QObject *)0);
             } else {
-                value = ep->scriptValueToVariant(scriptValue, data->property.propertyType());
+                value = ep->scriptValueToVariant(scriptValue, d->property.propertyType());
                 if (value.userType() == QMetaType::QObjectStar && !qvariant_cast<QObject*>(value)) {
                     // If the object is null, we extract the predicted type.  While this isn't
                     // 100% reliable, in many cases it gives us better error messages if we
@@ -172,73 +168,72 @@ void QDeclarativeBinding::update(QDeclarativePropertyPrivate::WriteFlags flags)
             }
 
 
-            if (data->error.isValid()) {
+            if (d->error.isValid()) {
 
-            } else if (isUndefined && data->property.isResettable()) {
+            } else if (isUndefined && d->property.isResettable()) {
 
-                data->property.reset();
+                d->property.reset();
 
-            } else if (isUndefined && data->property.propertyType() == qMetaTypeId<QVariant>()) {
+            } else if (isUndefined && d->property.propertyType() == qMetaTypeId<QVariant>()) {
 
-                QDeclarativePropertyPrivate::write(data->property, QVariant(), flags);
+                QDeclarativePropertyPrivate::write(d->property, QVariant(), flags);
 
             } else if (isUndefined) {
 
-                QUrl url = QUrl(data->url);
-                int line = data->line;
+                QUrl url = QUrl(d->url);
+                int line = d->line;
                 if (url.isEmpty()) url = QUrl(QLatin1String("<Unknown File>"));
 
-                data->error.setUrl(url);
-                data->error.setLine(line);
-                data->error.setColumn(-1);
-                data->error.setDescription(QLatin1String("Unable to assign [undefined] to ")
-                    + QLatin1String(QMetaType::typeName(data->property.propertyType()))
-                    + QLatin1String(" ") + data->property.name());
+                d->error.setUrl(url);
+                d->error.setLine(line);
+                d->error.setColumn(-1);
+                d->error.setDescription(QLatin1String("Unable to assign [undefined] to ") +
+                                        QLatin1String(QMetaType::typeName(d->property.propertyType())) +
+                                        QLatin1String(" ") + d->property.name());
 
             } else if (!scriptValue.isRegExp() && scriptValue.isFunction()) {
 
-                QUrl url = QUrl(data->url);
-                int line = data->line;
+                QUrl url = QUrl(d->url);
+                int line = d->line;
                 if (url.isEmpty()) url = QUrl(QLatin1String("<Unknown File>"));
 
-                data->error.setUrl(url);
-                data->error.setLine(line);
-                data->error.setColumn(-1);
-                data->error.setDescription(QLatin1String("Unable to assign a function to a property."));
+                d->error.setUrl(url);
+                d->error.setLine(line);
+                d->error.setColumn(-1);
+                d->error.setDescription(QLatin1String("Unable to assign a function to a property."));
 
-            } else if (data->property.object() &&
-                       !QDeclarativePropertyPrivate::write(data->property, value, flags)) {
+            } else if (d->property.object() &&
+                       !QDeclarativePropertyPrivate::write(d->property, value, flags)) {
 
-                QUrl url = QUrl(data->url);
-                int line = data->line;
+                QUrl url = QUrl(d->url);
+                int line = d->line;
                 if (url.isEmpty()) url = QUrl(QLatin1String("<Unknown File>"));
 
                 const char *valueType = 0;
                 if (value.userType() == QVariant::Invalid) valueType = "null";
                 else valueType = QMetaType::typeName(value.userType());
 
-                data->error.setUrl(url);
-                data->error.setLine(line);
-                data->error.setColumn(-1);
-                data->error.setDescription(QLatin1String("Unable to assign ") +
-                                           QLatin1String(valueType) +
-                                           QLatin1String(" to ") +
-                                           QLatin1String(QMetaType::typeName(data->property.propertyType())));
+                d->error.setUrl(url);
+                d->error.setLine(line);
+                d->error.setColumn(-1);
+                d->error.setDescription(QLatin1String("Unable to assign ") +
+                                        QLatin1String(valueType) +
+                                        QLatin1String(" to ") +
+                                        QLatin1String(QMetaType::typeName(d->property.propertyType())));
             }
 
-            if (data->error.isValid()) {
-               if (!data->addError(ep)) ep->warning(this->error());
+            if (d->error.isValid()) {
+               if (!d->addError(ep)) ep->warning(this->error());
             } else {
-                data->removeError();
+                d->removeError();
             }
         }
 
-        data->updating = false;
+        d->updating = false;
+        d->deleted = 0;
     } else {
-        qmlInfo(data->property.object()) << tr("Binding loop detected for property \"%1\"").arg(data->property.name());
+        qmlInfo(d->property.object()) << tr("Binding loop detected for property \"%1\"").arg(d->property.name());
     }
-
-    data->release();
 }
 
 void QDeclarativeBindingPrivate::emitValueChanged()
@@ -250,13 +245,13 @@ void QDeclarativeBindingPrivate::emitValueChanged()
 void QDeclarativeBinding::setEnabled(bool e, QDeclarativePropertyPrivate::WriteFlags flags)
 {
     Q_D(QDeclarativeBinding);
-    d->bindingData()->enabled = e;
+    d->enabled = e;
     setNotifyOnValueChanged(e);
 
     QDeclarativeAbstractBinding::setEnabled(e, flags);
 
     if (e) {
-        addToObject(d->bindingData()->property.object());
+        addToObject(d->property.object());
         update(flags);
     } else {
         removeFromObject();
@@ -266,14 +261,14 @@ void QDeclarativeBinding::setEnabled(bool e, QDeclarativePropertyPrivate::WriteF
 int QDeclarativeBinding::propertyIndex()
 {
     Q_D(QDeclarativeBinding);
-    return QDeclarativePropertyPrivate::bindingIndex(d->bindingData()->property);
+    return QDeclarativePropertyPrivate::bindingIndex(d->property);
 }
 
 bool QDeclarativeBinding::enabled() const
 {
     Q_D(const QDeclarativeBinding);
 
-    return d->bindingData()->enabled;
+    return d->enabled;
 }
 
 QString QDeclarativeBinding::expression() const
diff --git a/src/declarative/qml/qdeclarativebinding_p_p.h b/src/declarative/qml/qdeclarativebinding_p_p.h
index 617ec4b..6926158 100644
--- a/src/declarative/qml/qdeclarativebinding_p_p.h
+++ b/src/declarative/qml/qdeclarativebinding_p_p.h
@@ -60,30 +60,24 @@
 
 QT_BEGIN_NAMESPACE
 
-class QDeclarativeBindingData : public QDeclarativeExpressionData
-{
-public:
-    QDeclarativeBindingData();
-    virtual ~QDeclarativeBindingData();
-
-    bool updating:1;
-    bool enabled:1;
-
-    QDeclarativeProperty property;
-
-    virtual void refresh();
-};
-
 class QDeclarativeBindingPrivate : public QDeclarativeExpressionPrivate
 {
     Q_DECLARE_PUBLIC(QDeclarativeBinding)
 public:
     QDeclarativeBindingPrivate();
-
-    QDeclarativeBindingData *bindingData() { return static_cast<QDeclarativeBindingData *>(data); }
-    const QDeclarativeBindingData *bindingData() const { return static_cast<const QDeclarativeBindingData *>(data); }
+    ~QDeclarativeBindingPrivate();
 
     virtual void emitValueChanged();
+
+protected:
+    virtual void refresh();
+
+private:
+    bool updating:1;
+    bool enabled:1;
+    QDeclarativeProperty property; 
+
+    bool *deleted;
 };
 
 QT_END_NAMESPACE
diff --git a/src/declarative/qml/qdeclarativecontext_p.h b/src/declarative/qml/qdeclarativecontext_p.h
index 1f5aaf1..c5a039a 100644
--- a/src/declarative/qml/qdeclarativecontext_p.h
+++ b/src/declarative/qml/qdeclarativecontext_p.h
@@ -198,6 +198,7 @@ public:
     // context
     QDeclarativeComponentAttached *componentAttached;
 
+    // Return the outermost id for obj, if any.
     QString findObjectId(const QObject *obj) const;
 
     static QDeclarativeContextData *get(QDeclarativeContext *context) {
diff --git a/src/declarative/qml/qdeclarativeengine.cpp b/src/declarative/qml/qdeclarativeengine.cpp
index 00bc1b7..97ef99c 100644
--- a/src/declarative/qml/qdeclarativeengine.cpp
+++ b/src/declarative/qml/qdeclarativeengine.cpp
@@ -219,7 +219,7 @@ of their use.
 
 
 QDeclarativeEnginePrivate::QDeclarativeEnginePrivate(QDeclarativeEngine *e)
-: captureProperties(false), rootContext(0), currentExpression(0), isDebugging(false),
+: captureProperties(false), rootContext(0), isDebugging(false),
   outputWarningsToStdErr(true), contextClass(0), sharedContext(0), sharedScope(0),
   objectClass(0), valueTypeClass(0), globalClass(0), cleanup(0), erroredBindings(0),
   inProgressCreations(0), scriptEngine(this), workerScriptEngine(0), componentAttached(0),
diff --git a/src/declarative/qml/qdeclarativeengine_p.h b/src/declarative/qml/qdeclarativeengine_p.h
index f457b53..a5c8c38 100644
--- a/src/declarative/qml/qdeclarativeengine_p.h
+++ b/src/declarative/qml/qdeclarativeengine_p.h
@@ -162,7 +162,6 @@ public:
     QPODVector<CapturedProperty> capturedProperties;
 
     QDeclarativeContext *rootContext;
-    QDeclarativeExpression *currentExpression;
     bool isDebugging;
 
     bool outputWarningsToStdErr;
diff --git a/src/declarative/qml/qdeclarativeexpression.cpp b/src/declarative/qml/qdeclarativeexpression.cpp
index 96cdec1..9935e38 100644
--- a/src/declarative/qml/qdeclarativeexpression.cpp
+++ b/src/declarative/qml/qdeclarativeexpression.cpp
@@ -71,109 +71,95 @@ bool QDeclarativeDelayedError::addError(QDeclarativeEnginePrivate *e)
     return true;
 }
 
-QDeclarativeExpressionData::QDeclarativeExpressionData()
-: q(0), dataRef(0), expressionFunctionValid(false), expressionRewritten(false), me(0), 
-  trackChange(false), isShared(false), line(-1), guardList(0), guardListLength(0)
+QDeclarativeQtScriptExpression::QDeclarativeQtScriptExpression()
+: dataRef(0), expressionFunctionMode(ExplicitContext), scopeObject(0), trackChange(false), 
+  guardList(0), guardListLength(0), guardObject(0), guardObjectNotifyIndex(-1), deleted(0)
 {
 }
 
-QDeclarativeExpressionData::~QDeclarativeExpressionData()
+QDeclarativeQtScriptExpression::~QDeclarativeQtScriptExpression()
 {
     if (guardList) { delete [] guardList; guardList = 0; }
     if (dataRef) dataRef->release();
+    if (deleted) *deleted = true;
 }
 
 QDeclarativeExpressionPrivate::QDeclarativeExpressionPrivate()
-: data(new QDeclarativeExpressionData)
+: expressionFunctionValid(true), line(-1)
 {
-    data->q = this;
-}
-
-QDeclarativeExpressionPrivate::QDeclarativeExpressionPrivate(QDeclarativeExpressionData *d)
-: data(d)
-{
-    data->q = this;
 }
 
 QDeclarativeExpressionPrivate::~QDeclarativeExpressionPrivate()
 {
-    if (data) { 
-        delete [] data->guardList; 
-        data->guardList = 0; 
-        data->guardListLength = 0; 
-        data->q = 0; 
-        data->release(); 
-        data = 0; 
-    }
 }
 
 void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, const QString &expr, 
                                          QObject *me)
 {
-    data->expression = expr;
+    expression = expr;
 
-    data->QDeclarativeAbstractExpression::setContext(ctxt);
-    data->me = me;
+    QDeclarativeAbstractExpression::setContext(ctxt);
+    scopeObject = me;
+    expressionFunctionValid = false;
 }
 
-void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, void *expr, QDeclarativeRefCount *rc, 
-                                         QObject *me, const QString &url, int lineNumber)
+void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, void *expr, 
+                                         QDeclarativeRefCount *rc, 
+                                         QObject *me, const QString &srcUrl, int lineNumber)
 {
-    data->url = url;
-    data->line = lineNumber;
+    url = srcUrl;
+    line = lineNumber;
 
-    if (data->dataRef) data->dataRef->release();
-    data->dataRef = rc;
-    if (data->dataRef) data->dataRef->addref();
+    if (dataRef) dataRef->release();
+    dataRef = rc;
+    if (dataRef) dataRef->addref();
 
     quint32 *exprData = (quint32 *)expr;
     QDeclarativeCompiledData *dd = (QDeclarativeCompiledData *)rc;
 
-    data->expressionRewritten = true;
-    data->expression = QString::fromRawData((QChar *)(exprData + 2), exprData[1]);
+    expression = QString::fromRawData((QChar *)(exprData + 2), exprData[1]);
 
     int progIdx = *(exprData);
-    bool isShared = progIdx & 0x80000000;
+    bool isSharedProgram = progIdx & 0x80000000;
     progIdx &= 0x7FFFFFFF;
 
     QDeclarativeEngine *engine = ctxt->engine;
     QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);
     QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine);
 
-    if (isShared) {
+    if (isSharedProgram) {
 
         if (!dd->cachedClosures.at(progIdx)) {
             QScriptContext *scriptContext = QScriptDeclarativeClass::pushCleanContext(scriptEngine);
             scriptContext->pushScope(ep->contextClass->newSharedContext());
             scriptContext->pushScope(ep->globalClass->staticGlobalObject());
-            dd->cachedClosures[progIdx] = new QScriptValue(scriptEngine->evaluate(data->expression, data->url, data->line));
+            dd->cachedClosures[progIdx] = new QScriptValue(scriptEngine->evaluate(expression, url, line));
             scriptEngine->popContext();
         }
 
-        data->expressionFunction = *dd->cachedClosures.at(progIdx);
-        data->isShared = true;
-        data->expressionFunctionValid = true;
+        expressionFunction = *dd->cachedClosures.at(progIdx);
+        expressionFunctionMode = SharedContext;
+        expressionFunctionValid = true;
 
     } else {
 
 #if !defined(Q_OS_SYMBIAN) //XXX Why doesn't this work?
         if (!dd->cachedPrograms.at(progIdx)) {
-            dd->cachedPrograms[progIdx] =
-                new QScriptProgram(data->expression, data->url, data->line);
+            dd->cachedPrograms[progIdx] = new QScriptProgram(expression, url, line);
         }
 
-        data->expressionFunction = evalInObjectScope(ctxt, me, *dd->cachedPrograms.at(progIdx), 
-                                                     &data->expressionContext);
+        expressionFunction = evalInObjectScope(ctxt, me, *dd->cachedPrograms.at(progIdx), 
+                                                     &expressionContext);
 #else
-        data->expressionFunction = evalInObjectScope(ctxt, me, data->expression, 
-                                                     &data->expressionContext);
+        expressionFunction = evalInObjectScope(ctxt, me, expression, &expressionContext);
 #endif
 
-        data->expressionFunctionValid = true;
+        expressionFunctionMode = ExplicitContext;
+        expressionFunctionValid = true;
     }
 
-    data->QDeclarativeAbstractExpression::setContext(ctxt);
-    data->me = me;
+    QDeclarativeAbstractExpression::setContext(ctxt);
+    scopeObject = me;
 }
 
 QScriptValue QDeclarativeExpressionPrivate::evalInObjectScope(QDeclarativeContextData *context, QObject *object, 
@@ -240,6 +226,8 @@ QScriptValue QDeclarativeExpressionPrivate::evalInObjectScope(QDeclarativeContex
     \endcode
 */
 
+static int QDeclarativeExpression_notifyIdx = -1;
+
 /*!
     Create an invalid QDeclarativeExpression.
 
@@ -249,6 +237,11 @@ QScriptValue QDeclarativeExpressionPrivate::evalInObjectScope(QDeclarativeContex
 QDeclarativeExpression::QDeclarativeExpression()
 : QObject(*new QDeclarativeExpressionPrivate, 0)
 {
+    Q_D(QDeclarativeExpression);
+
+    if (QDeclarativeExpression_notifyIdx == -1) 
+        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
+    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
 }
 
 /*!  \internal */
@@ -260,6 +253,10 @@ QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, vo
 {
     Q_D(QDeclarativeExpression);
     d->init(ctxt, expr, rc, me, url, lineNumber);
+
+    if (QDeclarativeExpression_notifyIdx == -1) 
+        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
+    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
 }
 
 /*!
@@ -277,6 +274,10 @@ QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContext *ctxt,
 {
     Q_D(QDeclarativeExpression);
     d->init(QDeclarativeContextData::get(ctxt), expression, scope);
+
+    if (QDeclarativeExpression_notifyIdx == -1) 
+        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
+    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
 }
 
 /*! 
@@ -288,6 +289,10 @@ QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, QO
 {
     Q_D(QDeclarativeExpression);
     d->init(ctxt, expression, scope);
+
+    if (QDeclarativeExpression_notifyIdx == -1) 
+        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
+    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
 }
 
 /*!  \internal */
@@ -297,6 +302,10 @@ QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, QO
 {
     Q_D(QDeclarativeExpression);
     d->init(ctxt, expression, scope);
+
+    if (QDeclarativeExpression_notifyIdx == -1) 
+        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
+    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
 }
 
 /*!
@@ -313,7 +322,7 @@ QDeclarativeExpression::~QDeclarativeExpression()
 QDeclarativeEngine *QDeclarativeExpression::engine() const
 {
     Q_D(const QDeclarativeExpression);
-    return d->data->context()?d->data->context()->engine:0;
+    return d->context()?d->context()->engine:0;
 }
 
 /*!
@@ -323,7 +332,7 @@ QDeclarativeEngine *QDeclarativeExpression::engine() const
 QDeclarativeContext *QDeclarativeExpression::context() const
 {
     Q_D(const QDeclarativeExpression);
-    QDeclarativeContextData *data = d->data->context();
+    QDeclarativeContextData *data = d->context();
     return data?data->asQDeclarativeContext():0;
 }
 
@@ -333,7 +342,7 @@ QDeclarativeContext *QDeclarativeExpression::context() const
 QString QDeclarativeExpression::expression() const
 {
     Q_D(const QDeclarativeExpression);
-    return d->data->expression;
+    return d->expression;
 }
 
 /*!
@@ -343,12 +352,10 @@ void QDeclarativeExpression::setExpression(const QString &expression)
 {
     Q_D(QDeclarativeExpression);
 
-    d->clearGuards();
-
-    d->data->expression = expression;
-    d->data->expressionFunctionValid = false;
-    d->data->expressionRewritten = false;
-    d->data->expressionFunction = QScriptValue();
+    d->resetNotifyOnChange();
+    d->expression = expression;
+    d->expressionFunctionValid = false;
+    d->expressionFunction = QScriptValue();
 }
 
 void QDeclarativeExpressionPrivate::exceptionToError(QScriptEngine *scriptEngine, 
@@ -378,59 +385,108 @@ void QDeclarativeExpressionPrivate::exceptionToError(QScriptEngine *scriptEngine
     }
 }
 
-QScriptValue QDeclarativeExpressionPrivate::eval(QObject *secondaryScope, bool *isUndefined)
+bool QDeclarativeQtScriptExpression::notifyOnValueChange() const
 {
-    QDeclarativeExpressionData *data = this->data;
-    QDeclarativeEngine *engine = data->context()->engine;
-    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);
+    return trackChange;
+}
 
-    QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine);
+void QDeclarativeQtScriptExpression::setNotifyOnValueChange(bool notify)
+{
+    trackChange = notify;
+    if (!notify && guardList) 
+        clearGuards();
+}
 
-    if (!data->expressionFunctionValid) {
+void QDeclarativeQtScriptExpression::resetNotifyOnChange()
+{
+    clearGuards();
+}
 
-        QScriptContext *scriptContext = QScriptDeclarativeClass::pushCleanContext(scriptEngine);
-        data->expressionContext = ep->contextClass->newContext(data->context(), data->me);
-        scriptContext->pushScope(data->expressionContext);
-        scriptContext->pushScope(ep->globalClass->staticGlobalObject());
+void QDeclarativeQtScriptExpression::setNotifyObject(QObject *object, int notifyIndex)
+{
+    if (guardList) clearGuards();
+
+    if (!object || notifyIndex == -1) {
+        guardObject = 0;
+        notifyIndex = -1;
+    } else {
+        guardObject = object;
+        guardObjectNotifyIndex = notifyIndex;
+
+    }
+}
+
+QScriptValue QDeclarativeQtScriptExpression::scriptValue(QObject *secondaryScope, bool *isUndefined)
+{
+    Q_ASSERT(context() && context()->engine);
+    Q_ASSERT(!trackChange || (guardObject && guardObjectNotifyIndex != -1));
+
+    if (!expressionFunction.isValid()) {
+        if (isUndefined) *isUndefined = true;
+        return QScriptValue();
+    }
+
+    DeleteWatcher watcher(this);
+
+    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(context()->engine);
+
+    bool lastCaptureProperties = ep->captureProperties;
+    QPODVector<QDeclarativeEnginePrivate::CapturedProperty> lastCapturedProperties;
+    ep->captureProperties = trackChange;
+    ep->capturedProperties.copyAndClear(lastCapturedProperties);
+
+    QScriptValue value = eval(secondaryScope, isUndefined);
+
+    if (!watcher.wasDeleted() && trackChange) {
+        if (ep->capturedProperties.count() == 0) {
+
+            if (guardList) clearGuards();
 
-        if (data->expressionRewritten) {
-            data->expressionFunction = scriptEngine->evaluate(data->expression, 
-                                                              data->url, data->line);
         } else {
-            QDeclarativeRewrite::RewriteBinding rewriteBinding;
 
-            bool ok = true;
-            const QString code = rewriteBinding(data->expression, &ok);
-            if (!ok) {
-                scriptEngine->popContext();
-                return QScriptValue();
-            }
-            data->expressionFunction = scriptEngine->evaluate(code, data->url, data->line);
-        }
+            updateGuards(ep->capturedProperties);
 
-        scriptEngine->popContext();
-        data->expressionFunctionValid = true;
+        }
     }
 
+    lastCapturedProperties.copyAndClear(ep->capturedProperties);
+    ep->captureProperties = lastCaptureProperties;
+
+    return value;
+}
+
+QScriptValue QDeclarativeQtScriptExpression::eval(QObject *secondaryScope, bool *isUndefined)
+{
+    Q_ASSERT(context() && context()->engine);
+
+    DeleteWatcher watcher(this);
+
+    QDeclarativeEngine *engine = context()->engine;
+    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);
+
+    QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine);
+
     QDeclarativeContextData *oldSharedContext = 0;
     QObject *oldSharedScope = 0;
     QObject *oldOverride = 0;
-    if (data->isShared) {
+    bool isShared = (expressionFunctionMode == SharedContext);
+
+    if (isShared) {
         oldSharedContext = ep->sharedContext;
         oldSharedScope = ep->sharedScope;
-        ep->sharedContext = data->context();
-        ep->sharedScope = data->me;
+        ep->sharedContext = context();
+        ep->sharedScope = scopeObject;
     } else {
-        oldOverride = ep->contextClass->setOverrideObject(data->expressionContext, secondaryScope);
+        oldOverride = ep->contextClass->setOverrideObject(expressionContext, secondaryScope);
     }
 
-    QScriptValue svalue = data->expressionFunction.call();
+    QScriptValue svalue = expressionFunction.call(); // This could cause this to be deleted
 
-    if (data->isShared) {
+    if (isShared) {
         ep->sharedContext = oldSharedContext;
         ep->sharedScope = oldSharedScope;
-    } else {
-        ep->contextClass->setOverrideObject(data->expressionContext, oldOverride);
+    } else if (!watcher.wasDeleted()) {
+        ep->contextClass->setOverrideObject(expressionContext, oldOverride);
     }
 
     if (isUndefined)
@@ -438,63 +494,134 @@ QScriptValue QDeclarativeExpressionPrivate::eval(QObject *secondaryScope, bool *
 
     // Handle exception
     if (scriptEngine->hasUncaughtException()) {
-       exceptionToError(scriptEngine, data->error);
+        if (!watcher.wasDeleted()) 
+           QDeclarativeExpressionPrivate::exceptionToError(scriptEngine, error);
+
        scriptEngine->clearExceptions();
        return QScriptValue();
     } else {
-        data->error = QDeclarativeError();
+        if (!watcher.wasDeleted())
+            error = QDeclarativeError();
+
         return svalue;
     }
 }
 
-QScriptValue QDeclarativeExpressionPrivate::scriptValue(QObject *secondaryScope, bool *isUndefined)
+void QDeclarativeQtScriptExpression::updateGuards(const QPODVector<QDeclarativeEnginePrivate::CapturedProperty> &properties)
 {
-    Q_Q(QDeclarativeExpression);
-    Q_ASSERT(q->engine());
+    Q_ASSERT(guardObject);
+    Q_ASSERT(guardObjectNotifyIndex != -1);
 
-    if (data->expression.isEmpty())
-        return QScriptValue();
+    if (properties.count() != guardListLength) {
+        QDeclarativeNotifierEndpoint *newGuardList = new QDeclarativeNotifierEndpoint[properties.count()];
 
-    QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(q->engine());
+        for (int ii = 0; ii < qMin(guardListLength, properties.count()); ++ii) 
+           guardList[ii].copyAndClear(newGuardList[ii]);
 
-    QDeclarativeExpression *lastCurrentExpression = ep->currentExpression;
-    bool lastCaptureProperties = ep->captureProperties;
-    QPODVector<QDeclarativeEnginePrivate::CapturedProperty> lastCapturedProperties;
-    ep->capturedProperties.copyAndClear(lastCapturedProperties);
+        delete [] guardList;
+        guardList = newGuardList;
+        guardListLength = properties.count();
+    }
 
-    ep->currentExpression = q;
-    ep->captureProperties = data->trackChange;
+    bool outputWarningHeader = false;
+    bool noChanges = true;
+    for (int ii = 0; ii < properties.count(); ++ii) {
+        QDeclarativeNotifierEndpoint &guard = guardList[ii];
+        const QDeclarativeEnginePrivate::CapturedProperty &property = properties.at(ii);
 
-    // This object might be deleted during the eval
-    QDeclarativeExpressionData *localData = data;
-    localData->addref();
+        guard.target = guardObject;
+        guard.targetMethod = guardObjectNotifyIndex;
 
-    QScriptValue value = eval(secondaryScope, isUndefined);
+        if (property.notifier != 0) {
 
-    ep->currentExpression = lastCurrentExpression;
-    ep->captureProperties = lastCaptureProperties;
+            if (!noChanges && guard.isConnected(property.notifier)) {
+                // Nothing to do
 
-    // Check if we were deleted
-    if (localData->q) {
-        if ((!data->trackChange || !ep->capturedProperties.count()) && data->guardList) {
-            clearGuards();
-        } else if(data->trackChange) {
-            updateGuards(ep->capturedProperties);
+            } else {
+                noChanges = false;
+
+                bool existing = false;
+                for (int jj = 0; !existing && jj < ii; ++jj) 
+                    if (guardList[jj].isConnected(property.notifier)) 
+                        existing = true;
+
+                if (existing) {
+                    // duplicate
+                    guard.disconnect();
+                } else {
+                    guard.connect(property.notifier);
+                }
+            }
+
+
+        } else if (property.notifyIndex != -1) {
+
+            if (!noChanges && guard.isConnected(property.object, property.notifyIndex)) {
+                // Nothing to do
+
+            } else {
+                noChanges = false;
+
+                bool existing = false;
+                for (int jj = 0; !existing && jj < ii; ++jj) 
+                    if (guardList[jj].isConnected(property.object, property.notifyIndex)) 
+                        existing = true;
+
+                if (existing) {
+                    // duplicate
+                    guard.disconnect();
+                } else {
+                    guard.connect(property.object, property.notifyIndex);
+                }
+            }
+
+        } else {
+            if (!outputWarningHeader) {
+                outputWarningHeader = true;
+                qWarning() << "QDeclarativeExpression: Expression" << expression
+                           << "depends on non-NOTIFYable properties:";
+            }
+
+            const QMetaObject *metaObj = property.object->metaObject();
+            QMetaProperty metaProp = metaObj->property(property.coreIndex);
+
+            qWarning().nospace() << "    " << metaObj->className() << "::" << metaProp.name();
         }
     }
+}
 
-    localData->release();
+QScriptValue QDeclarativeExpressionPrivate::scriptValue(QObject *secondaryScope, bool *isUndefined)
+{
+    if (!expressionFunctionValid) {
+        QDeclarativeEngine *engine = context()->engine;
+        QDeclarativeEnginePrivate *ep = QDeclarativeEnginePrivate::get(engine);
 
-    lastCapturedProperties.copyAndClear(ep->capturedProperties);
+        QScriptEngine *scriptEngine = QDeclarativeEnginePrivate::getScriptEngine(engine);
 
-    return value;
+        QScriptContext *scriptContext = QScriptDeclarativeClass::pushCleanContext(scriptEngine);
+        expressionContext = ep->contextClass->newContext(context(), scopeObject);
+        scriptContext->pushScope(expressionContext);
+        scriptContext->pushScope(ep->globalClass->staticGlobalObject());
+
+        QDeclarativeRewrite::RewriteBinding rewriteBinding;
+        bool ok = true;
+        const QString code = rewriteBinding(expression, &ok);
+        if (ok) 
+            expressionFunction = scriptEngine->evaluate(code, url, line);
+
+        scriptEngine->popContext();
+        expressionFunctionMode = ExplicitContext;
+        expressionFunctionValid = true;
+    }
+
+    return QDeclarativeQtScriptExpression::scriptValue(secondaryScope, isUndefined);
 }
 
 QVariant QDeclarativeExpressionPrivate::value(QObject *secondaryScope, bool *isUndefined)
 {
     Q_Q(QDeclarativeExpression);
 
-    if (!data || !data->context() || !data->context()->isValid()) {
+    if (!context() || !context()->isValid()) {
         qWarning("QDeclarativeExpression: Attempted to evaluate an expression in an invalid context");
         return QVariant();
     }
@@ -526,7 +653,7 @@ value changes.
 bool QDeclarativeExpression::notifyOnValueChanged() const
 {
     Q_D(const QDeclarativeExpression);
-    return d->data->trackChange;
+    return d->notifyOnValueChange();
 }
 
 /*!
@@ -548,7 +675,7 @@ bool QDeclarativeExpression::notifyOnValueChanged() const
 void QDeclarativeExpression::setNotifyOnValueChanged(bool notifyOnChange)
 {
     Q_D(QDeclarativeExpression);
-    d->data->trackChange = notifyOnChange;
+    d->setNotifyOnValueChange(notifyOnChange);
 }
 
 /*!
@@ -558,7 +685,7 @@ void QDeclarativeExpression::setNotifyOnValueChanged(bool notifyOnChange)
 QString QDeclarativeExpression::sourceFile() const
 {
     Q_D(const QDeclarativeExpression);
-    return d->data->url;
+    return d->url;
 }
 
 /*!
@@ -568,7 +695,7 @@ QString QDeclarativeExpression::sourceFile() const
 int QDeclarativeExpression::lineNumber() const
 {
     Q_D(const QDeclarativeExpression);
-    return d->data->line;
+    return d->line;
 }
 
 /*!
@@ -578,8 +705,8 @@ int QDeclarativeExpression::lineNumber() const
 void QDeclarativeExpression::setSourceLocation(const QString &url, int line)
 {
     Q_D(QDeclarativeExpression);
-    d->data->url = url;
-    d->data->line = line;
+    d->url = url;
+    d->line = line;
 }
 
 /*!
@@ -591,7 +718,7 @@ void QDeclarativeExpression::setSourceLocation(const QString &url, int line)
 QObject *QDeclarativeExpression::scopeObject() const
 {
     Q_D(const QDeclarativeExpression);
-    return d->data->me;
+    return d->scopeObject;
 }
 
 /*!
@@ -603,7 +730,7 @@ QObject *QDeclarativeExpression::scopeObject() const
 bool QDeclarativeExpression::hasError() const
 {
     Q_D(const QDeclarativeExpression);
-    return d->data->error.isValid();
+    return d->error.isValid();
 }
 
 /*!
@@ -615,7 +742,7 @@ bool QDeclarativeExpression::hasError() const
 void QDeclarativeExpression::clearError()
 {
     Q_D(QDeclarativeExpression);
-    d->data->error = QDeclarativeError();
+    d->error = QDeclarativeError();
 }
 
 /*!
@@ -628,7 +755,7 @@ void QDeclarativeExpression::clearError()
 QDeclarativeError QDeclarativeExpression::error() const
 {
     Q_D(const QDeclarativeExpression);
-    return d->data->error;
+    return d->error;
 }
 
 /*! \internal */
@@ -637,98 +764,11 @@ void QDeclarativeExpressionPrivate::_q_notify()
     emitValueChanged();
 }
 
-void QDeclarativeExpressionPrivate::clearGuards()
-{
-    delete [] data->guardList; 
-    data->guardList = 0; 
-    data->guardListLength = 0;
-}
-
-void QDeclarativeExpressionPrivate::updateGuards(const QPODVector<QDeclarativeEnginePrivate::CapturedProperty> &properties)
+void QDeclarativeQtScriptExpression::clearGuards()
 {
-    Q_Q(QDeclarativeExpression);
-
-    static int notifyIdx = -1;
-    if (notifyIdx == -1) 
-        notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
-
-    if (properties.count() != data->guardListLength) {
-        QDeclarativeNotifierEndpoint *newGuardList = 
-            new QDeclarativeNotifierEndpoint[properties.count()];
-
-        for (int ii = 0; ii < qMin(data->guardListLength, properties.count()); ++ii) 
-           data->guardList[ii].copyAndClear(newGuardList[ii]);
-
-        delete [] data->guardList;
-        data->guardList = newGuardList;
-        data->guardListLength = properties.count();
-    }
-
-    bool outputWarningHeader = false;
-    bool noChanges = true;
-    for (int ii = 0; ii < properties.count(); ++ii) {
-        QDeclarativeNotifierEndpoint &guard = data->guardList[ii];
-        const QDeclarativeEnginePrivate::CapturedProperty &property = properties.at(ii);
-
-        guard.target = q;
-        guard.targetMethod = notifyIdx;
-
-        if (property.notifier != 0) {
-
-            if (!noChanges && guard.isConnected(property.notifier)) {
-                // Nothing to do
-
-            } else {
-                noChanges = false;
-
-                bool existing = false;
-                for (int jj = 0; !existing && jj < ii; ++jj) 
-                    if (data->guardList[jj].isConnected(property.notifier)) 
-                        existing = true;
-
-                if (existing) {
-                    // duplicate
-                    guard.disconnect();
-                } else {
-                    guard.connect(property.notifier);
-                }
-            }
-
-
-        } else if (property.notifyIndex != -1) {
-
-            if (!noChanges && guard.isConnected(property.object, property.notifyIndex)) {
-                // Nothing to do
-
-            } else {
-                noChanges = false;
-
-                bool existing = false;
-                for (int jj = 0; !existing && jj < ii; ++jj) 
-                    if (data->guardList[jj].isConnected(property.object, property.notifyIndex)) 
-                        existing = true;
-
-                if (existing) {
-                    // duplicate
-                    guard.disconnect();
-                } else {
-                    guard.connect(property.object, property.notifyIndex);
-                }
-            }
-
-        } else {
-            if (!outputWarningHeader) {
-                outputWarningHeader = true;
-                qWarning() << "QDeclarativeExpression: Expression" << q->expression()
-                           << "depends on non-NOTIFYable properties:";
-            }
-
-            const QMetaObject *metaObj = property.object->metaObject();
-            QMetaProperty metaProp = metaObj->property(property.coreIndex);
-
-            qWarning().nospace() << "    " << metaObj->className() << "::" << metaProp.name();
-        }
-    }
+    delete [] guardList; 
+    guardList = 0; 
+    guardListLength = 0;
 }
 
 /*!
diff --git a/src/declarative/qml/qdeclarativeexpression_p.h b/src/declarative/qml/qdeclarativeexpression_p.h
index 4ff3162..b629e20 100644
--- a/src/declarative/qml/qdeclarativeexpression_p.h
+++ b/src/declarative/qml/qdeclarativeexpression_p.h
@@ -107,56 +107,73 @@ private:
     QDeclarativeDelayedError **prevError;
 };
 
-class QDeclarativeExpressionData : public QDeclarativeAbstractExpression, public QDeclarativeDelayedError, public QDeclarativeRefCount
+class QDeclarativeQtScriptExpression : public QDeclarativeAbstractExpression, 
+                                       public QDeclarativeDelayedError
 {
 public:
-    QDeclarativeExpressionData();
-    virtual ~QDeclarativeExpressionData();
+    enum Mode { SharedContext, ExplicitContext };
 
-    QDeclarativeExpressionPrivate *q;
+    QDeclarativeQtScriptExpression();
+    virtual ~QDeclarativeQtScriptExpression();
 
     QDeclarativeRefCount *dataRef;
+
     QString expression;
-    bool expressionFunctionValid:1;
-    bool expressionRewritten:1;
+
+    Mode expressionFunctionMode;
     QScriptValue expressionFunction;
-    QScriptValue expressionContext;
 
-    QObject *me;
-    bool trackChange;
+    QScriptValue expressionContext; // Only used in ExplicitContext
+    QObject *scopeObject;           // Only used in SharedContext
 
-    bool isShared;
+    bool notifyOnValueChange() const;
+    void setNotifyOnValueChange(bool);
+    void resetNotifyOnChange();
+    void setNotifyObject(QObject *, int );
 
-    QString url; // This is a QString for a reason.  QUrls are slooooooow...
-    int line;
+    QScriptValue scriptValue(QObject *secondaryScope, bool *isUndefined);
+
+    class DeleteWatcher {
+    public:
+        inline DeleteWatcher(QDeclarativeQtScriptExpression *data);
+        inline ~DeleteWatcher();
+        inline bool wasDeleted() const;
+    private:
+        bool *m_wasDeleted;
+        bool m_wasDeletedStorage;
+        QDeclarativeQtScriptExpression *m_d;
+    };
+
+private:
+    void clearGuards();
+    QScriptValue eval(QObject *secondaryScope, bool *isUndefined);
+    void updateGuards(const QPODVector<QDeclarativeEnginePrivate::CapturedProperty> &properties);
+
+    bool trackChange;
 
     QDeclarativeNotifierEndpoint *guardList;
     int guardListLength;
+
+    QObject *guardObject;
+    int guardObjectNotifyIndex;
+    bool *deleted;
 };
 
 class QDeclarativeExpression;
 class QString;
-class QDeclarativeExpressionPrivate : public QObjectPrivate
+class QDeclarativeExpressionPrivate : public QObjectPrivate, public QDeclarativeQtScriptExpression
 {
     Q_DECLARE_PUBLIC(QDeclarativeExpression)
 public:
     QDeclarativeExpressionPrivate();
-    QDeclarativeExpressionPrivate(QDeclarativeExpressionData *);
     ~QDeclarativeExpressionPrivate();
 
     void init(QDeclarativeContextData *, const QString &, QObject *);
     void init(QDeclarativeContextData *, void *, QDeclarativeRefCount *, QObject *, const QString &, int);
 
-    QDeclarativeExpressionData *data;
-
     QVariant value(QObject *secondaryScope = 0, bool *isUndefined = 0);
     QScriptValue scriptValue(QObject *secondaryScope = 0, bool *isUndefined = 0);
 
-    QScriptValue eval(QObject *secondaryScope, bool *isUndefined = 0);
-
-    void updateGuards(const QPODVector<QDeclarativeEnginePrivate::CapturedProperty> &properties);
-    void clearGuards();
-
     static QDeclarativeExpressionPrivate *get(QDeclarativeExpression *expr) {
         return static_cast<QDeclarativeExpressionPrivate *>(QObjectPrivate::get(expr));
     }
@@ -172,8 +189,32 @@ public:
                                           int, QScriptValue *);
     static QScriptValue evalInObjectScope(QDeclarativeContextData *, QObject *, const QScriptProgram &, 
                                           QScriptValue *);
+
+    bool expressionFunctionValid:1;
+
+    QString url; // This is a QString for a reason.  QUrls are slooooooow...
+    int line;
 };
 
+QDeclarativeQtScriptExpression::DeleteWatcher::DeleteWatcher(QDeclarativeQtScriptExpression *data)
+: m_wasDeletedStorage(false), m_d(data) 
+{
+    if (!m_d->deleted) 
+        m_d->deleted = &m_wasDeletedStorage; 
+    m_wasDeleted = m_d->deleted;
+}
+
+QDeclarativeQtScriptExpression::DeleteWatcher::~DeleteWatcher() 
+{
+    if (false == *m_wasDeleted && m_wasDeleted == m_d->deleted)
+        m_d->deleted = 0;
+}
+
+bool QDeclarativeQtScriptExpression::DeleteWatcher::wasDeleted() const 
+{ 
+    return *m_wasDeleted; 
+}
+
 QT_END_NAMESPACE
 
 #endif // QDECLARATIVEEXPRESSION_P_H