Fix default property preventing signals from being emitted.

Change the way connectAlias works so that even if the target
for the connection is not available immediately, anything that
is bound to it is notified when the target is changed.

(Fix is authored by Aaron).

Task-number: QTBUG-21580
Change-Id: Ida23c0e620069c50b123c71b5078929d4c7ec4e4
Reviewed-by: Martin Jones <martin.jones@nokia.com>

5 files changed, 279 insertions, 22 deletions

diff --git a/src/declarative/qml/ftw/ftw.pri b/src/declarative/qml/ftw/ftw.pri
index 9d114e2b05..9df0af8146 100644
--- a/src/declarative/qml/ftw/ftw.pri
+++ b/src/declarative/qml/ftw/ftw.pri
@@ -13,6 +13,7 @@ HEADERS +=  \
     $$PWD/qrecursionwatcher_p.h \
     $$PWD/qdeletewatcher_p.h \
     $$PWD/qrecyclepool_p.h \
+    $$PWD/qflagpointer_p.h \
 
 SOURCES += \
     $$PWD/qintrusivelist.cpp \
diff --git a/src/declarative/qml/ftw/qflagpointer_p.h b/src/declarative/qml/ftw/qflagpointer_p.h
new file mode 100644
index 0000000000..20f829bcc0
--- /dev/null
+++ b/src/declarative/qml/ftw/qflagpointer_p.h
@@ -0,0 +1,182 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QFLAGPOINTER_P_H
+#define QFLAGPOINTER_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtCore/qglobal.h>
+
+QT_BEGIN_NAMESPACE
+
+template<typename T>
+class QFlagPointer {
+public:
+    inline QFlagPointer();
+    inline QFlagPointer(T *);
+    inline QFlagPointer(const QFlagPointer<T> &o);
+
+    inline bool isNull() const;
+
+    inline bool flag() const;
+    inline void setFlag();
+    inline void clearFlag();
+
+    inline bool flag2() const;
+    inline void setFlag2();
+    inline void clearFlag2();
+
+    inline QFlagPointer<T> &operator=(const QFlagPointer &o);
+    inline QFlagPointer<T> &operator=(T *);
+
+    inline T *operator->() const;
+    inline T *operator*() const;
+
+private:
+    intptr_t ptr_value;
+
+    static const intptr_t FlagBit = 0x1;
+    static const intptr_t Flag2Bit = 0x2;
+    static const intptr_t FlagsMask = FlagBit | Flag2Bit;
+};
+
+template<typename T>
+QFlagPointer<T>::QFlagPointer()
+: ptr_value(0)
+{
+}
+
+template<typename T>
+QFlagPointer<T>::QFlagPointer(T *v)
+: ptr_value(intptr_t(v))
+{
+    Q_ASSERT((ptr_value & FlagsMask) == 0);
+}
+
+template<typename T>
+QFlagPointer<T>::QFlagPointer(const QFlagPointer<T> &o)
+: ptr_value(o.ptr_value)
+{
+}
+
+template<typename T>
+bool QFlagPointer<T>::isNull() const
+{
+    return 0 == (ptr_value & (~FlagsMask));
+}
+
+template<typename T>
+bool QFlagPointer<T>::flag() const
+{
+    return ptr_value & FlagBit;
+}
+
+template<typename T>
+void QFlagPointer<T>::setFlag()
+{
+    ptr_value |= FlagBit;
+}
+
+template<typename T>
+void QFlagPointer<T>::clearFlag()
+{
+    ptr_value &= ~FlagBit;
+}
+
+template<typename T>
+bool QFlagPointer<T>::flag2() const
+{
+    return ptr_value & Flag2Bit;
+}
+
+template<typename T>
+void QFlagPointer<T>::setFlag2()
+{
+    ptr_value|= Flag2Bit;
+}
+
+template<typename T>
+void QFlagPointer<T>::clearFlag2()
+{
+    ptr_value &= ~Flag2Bit;
+}
+
+template<typename T>
+QFlagPointer<T> &QFlagPointer<T>::operator=(const QFlagPointer &o)
+{
+    ptr_value = o.ptr_value;
+    return *this;
+}
+
+template<typename T>
+QFlagPointer<T> &QFlagPointer<T>::operator=(T *o)
+{
+    Q_ASSERT((intptr_t(o) & FlagsMask) == 0);
+
+    ptr_value = intptr_t(o) | (ptr_value & FlagsMask);
+    return *this;
+}
+
+template<typename T>
+T *QFlagPointer<T>::operator->() const
+{
+    return (T *)(ptr_value & ~FlagsMask);
+}
+
+template<typename T>
+T *QFlagPointer<T>::operator*() const
+{
+    return (T *)(ptr_value & ~FlagsMask);
+}
+
+QT_END_NAMESPACE
+
+#endif // QFLAGPOINTER_P_H
diff --git a/src/declarative/qml/qdeclarativecontext_p.h b/src/declarative/qml/qdeclarativecontext_p.h
index fb6473cb7a..92aa7bfafb 100644
--- a/src/declarative/qml/qdeclarativecontext_p.h
+++ b/src/declarative/qml/qdeclarativecontext_p.h
@@ -67,10 +67,12 @@
 #include <QtCore/qset.h>
 
 #include <private/qobject_p.h>
-#include "qdeclarativeguard_p.h"
+#include <private/qflagpointer_p.h>
+#include <private/qdeclarativeguard_p.h>
 
 #include <private/qv8_p.h>
 
+
 QT_BEGIN_NAMESPACE
 
 class QV8Bindings;
@@ -184,13 +186,13 @@ public:
     // id guards
     struct ContextGuard : public QDeclarativeGuard<QObject>
     {
-        ContextGuard() : context(0) {}
-        inline ContextGuard &operator=(QObject *obj)
-        { QDeclarativeGuard<QObject>::operator=(obj); return *this; }
-        virtual void objectDestroyed(QObject *) { 
-            if (context->contextObject && !QObjectPrivate::get(context->contextObject)->wasDeleted) bindings.notify(); 
-        }
-        QDeclarativeContextData *context;
+        inline ContextGuard();
+        inline ContextGuard &operator=(QObject *obj);
+        inline void objectDestroyed(QObject *);
+
+        inline bool wasSet() const;
+
+        QFlagPointer<QDeclarativeContextData> context;
         QDeclarativeNotifier bindings;
     };
     ContextGuard *idValues;
@@ -302,6 +304,30 @@ QDeclarativeGuardedContextData::operator=(QDeclarativeContextData *d)
     return *this;
 }
 
+QDeclarativeContextData::ContextGuard::ContextGuard()
+: context(0)
+{
+}
+
+QDeclarativeContextData::ContextGuard &QDeclarativeContextData::ContextGuard::operator=(QObject *obj)
+{
+    QDeclarativeGuard<QObject>::operator=(obj);
+    context.setFlag();
+    bindings.notify(); // For alias connections
+    return *this;
+}
+
+void QDeclarativeContextData::ContextGuard::objectDestroyed(QObject *)
+{
+    if (context->contextObject && !QObjectPrivate::get(context->contextObject)->wasDeleted)
+        bindings.notify();
+}
+
+bool QDeclarativeContextData::ContextGuard::wasSet() const
+{
+    return context.flag();
+}
+
 QT_END_NAMESPACE
 
 #endif // QDECLARATIVECONTEXT_P_H
diff --git a/src/declarative/qml/qdeclarativevmemetaobject.cpp b/src/declarative/qml/qdeclarativevmemetaobject.cpp
index 9cdec020a7..f768d8c1ae 100644
--- a/src/declarative/qml/qdeclarativevmemetaobject.cpp
+++ b/src/declarative/qml/qdeclarativevmemetaobject.cpp
@@ -94,6 +94,17 @@ private:
     inline void cleanup();
 };
 
+class QDeclarativeVMEMetaObjectEndpoint : public QDeclarativeNotifierEndpoint
+{
+public:
+    QDeclarativeVMEMetaObjectEndpoint();
+    static void vmecallback(QDeclarativeNotifierEndpoint *);
+    void tryConnect();
+
+    QFlagPointer<QDeclarativeVMEMetaObject> metaObject;
+};
+
+
 QDeclarativeVMEVariant::QDeclarativeVMEVariant()
 : type(QVariant::Invalid)
 {
@@ -378,13 +389,50 @@ void QDeclarativeVMEVariant::setValue(const QJSValue &v)
     }
 }
 
+QDeclarativeVMEMetaObjectEndpoint::QDeclarativeVMEMetaObjectEndpoint()
+{
+    callback = &vmecallback;
+}
+
+void QDeclarativeVMEMetaObjectEndpoint::vmecallback(QDeclarativeNotifierEndpoint *e)
+{
+    QDeclarativeVMEMetaObjectEndpoint *vmee = static_cast<QDeclarativeVMEMetaObjectEndpoint*>(e);
+    vmee->tryConnect();
+}
+
+void QDeclarativeVMEMetaObjectEndpoint::tryConnect()
+{
+    if (metaObject.flag())
+        return;
+
+    int aliasId = this - metaObject->aliasEndpoints;
+
+    QDeclarativeVMEMetaData::AliasData *d = metaObject->metaData->aliasData() + aliasId;
+    if (!d->isObjectAlias()) {
+        QDeclarativeContextData *ctxt = metaObject->ctxt;
+        QObject *target = ctxt->idValues[d->contextIdx].data();
+        if (!target)
+            return;
+
+        QMetaProperty prop = target->metaObject()->property(d->propertyIndex());
+        if (prop.hasNotifySignal()) {
+            int sigIdx = metaObject->methodOffset + aliasId + metaObject->metaData->propertyCount;
+            QDeclarativePropertyPrivate::connect(target, prop.notifySignalIndex(),
+                                                 metaObject->object, sigIdx);
+        }
+    }
+
+    metaObject.setFlag();
+}
+
 QDeclarativeVMEMetaObject::QDeclarativeVMEMetaObject(QObject *obj,
                                                      const QMetaObject *other, 
                                                      const QDeclarativeVMEMetaData *meta,
                                                      QDeclarativeCompiledData *cdata)
 : QV8GCCallback::Node(GcPrologueCallback), object(obj), compiledData(cdata),
   ctxt(QDeclarativeData::get(obj, true)->outerContext), metaData(meta), data(0),
-  firstVarPropertyIndex(-1), varPropertiesInitialized(false), v8methods(0), parent(0)
+  aliasEndpoints(0), firstVarPropertyIndex(-1), varPropertiesInitialized(false),
+  v8methods(0), parent(0)
 {
     compiledData->addref();
 
@@ -423,6 +471,7 @@ QDeclarativeVMEMetaObject::~QDeclarativeVMEMetaObject()
     compiledData->release();
     delete parent;
     delete [] data;
+    delete [] aliasEndpoints;
 
     for (int ii = 0; v8methods && ii < metaData->methodCount; ++ii) {
         qPersistentDispose(v8methods[ii]);
@@ -974,25 +1023,20 @@ bool QDeclarativeVMEMetaObject::aliasTarget(int index, QObject **target, int *co
 void QDeclarativeVMEMetaObject::connectAlias(int aliasId)
 {
     if (!aConnected.testBit(aliasId)) {
-        aConnected.setBit(aliasId);
 
-        QDeclarativeContext *context = ctxt->asQDeclarativeContext();
-        QDeclarativeContextPrivate *ctxtPriv = QDeclarativeContextPrivate::get(context);
+        if (!aliasEndpoints)
+            aliasEndpoints = new QDeclarativeVMEMetaObjectEndpoint[metaData->aliasCount];
+
+        aConnected.setBit(aliasId);
 
         QDeclarativeVMEMetaData::AliasData *d = metaData->aliasData() + aliasId;
 
-        QObject *target = ctxtPriv->data->idValues[d->contextIdx].data();
-        if (!target) 
-            return;
+        QDeclarativeVMEMetaObjectEndpoint *endpoint = aliasEndpoints + aliasId;
+        endpoint->metaObject = this;
 
-        int sigIdx = methodOffset + aliasId + metaData->propertyCount;
-        QMetaObject::connect(context, d->contextIdx + ctxtPriv->notifyIndex, object, sigIdx);
+        endpoint->connect(&ctxt->idValues[d->contextIdx].bindings);
 
-        if (!d->isObjectAlias()) {
-            QMetaProperty prop = target->metaObject()->property(d->propertyIndex());
-            if (prop.hasNotifySignal())
-                QDeclarativePropertyPrivate::connect(target, prop.notifySignalIndex(), object, sigIdx);
-        }
+        endpoint->tryConnect();
     }
 }
 
diff --git a/src/declarative/qml/qdeclarativevmemetaobject_p.h b/src/declarative/qml/qdeclarativevmemetaobject_p.h
index 6076dcfe61..de0ac9e4d9 100644
--- a/src/declarative/qml/qdeclarativevmemetaobject_p.h
+++ b/src/declarative/qml/qdeclarativevmemetaobject_p.h
@@ -139,6 +139,7 @@ struct QDeclarativeVMEMetaData
 class QV8QObjectWrapper;
 class QDeclarativeVMEVariant;
 class QDeclarativeRefCount;
+class QDeclarativeVMEMetaObjectEndpoint;
 class Q_AUTOTEST_EXPORT QDeclarativeVMEMetaObject : public QAbstractDynamicMetaObject,
                                                     public QV8GCCallback::Node
 {
@@ -161,6 +162,8 @@ protected:
     virtual int metaCall(QMetaObject::Call _c, int _id, void **_a);
 
 private:
+    friend class QDeclarativeVMEMetaObjectEndpoint;
+
     QObject *object;
     QDeclarativeCompiledData *compiledData;
     QDeclarativeGuardedContextData ctxt;
@@ -170,6 +173,7 @@ private:
     int methodOffset;
 
     QDeclarativeVMEVariant *data;
+    QDeclarativeVMEMetaObjectEndpoint *aliasEndpoints;
 
     v8::Persistent<v8::Array> varProperties;
     int firstVarPropertyIndex;