Merge branch 'master' of scm.dev.nokia.troll.no:qt/qt-qml-staging into master-integration

* 'master' of scm.dev.nokia.troll.no:qt/qt-qml-staging:
  QmlDebug: Fix QmlOstPlugin compilation failure
  QmlDebug: Fix QmlOstPlugin compilation failure
  Enable performance monitoring at application startup.
  Augment documentation
  QmlDebugger: removing slots in Live Preview
  QmlDebugger: adding slots to items in Live Preview
  Fixed license header
  Fixed compile on Windows
  Added forgotten file qdeclarativeobserverinterface_p.h
  Removed some trailing whitespace
  Introduced a CONFIG option that enables declarative debug services
  Moved the QML Observer Service and related functionality into Qt
  QDeclarativeDebugServer: Send hello answer before any service messages
  Removed some superfluous semicolons

17 files changed, 1512 insertions, 19 deletions

diff --git a/src/declarative/debugger/debugger.pri b/src/declarative/debugger/debugger.pri
index 75287b4..044db3c 100644
--- a/src/declarative/debugger/debugger.pri
+++ b/src/declarative/debugger/debugger.pri
@@ -8,7 +8,10 @@ SOURCES += \
     $$PWD/qdeclarativedebug.cpp \
     $$PWD/qdeclarativedebugtrace.cpp \
     $$PWD/qdeclarativedebughelper.cpp \
-    $$PWD/qdeclarativedebugserver.cpp
+    $$PWD/qdeclarativedebugserver.cpp \
+    $$PWD/qdeclarativeobserverservice.cpp \
+    $$PWD/qjsdebuggeragent.cpp \
+    $$PWD/qjsdebugservice.cpp
 
 HEADERS += \
     $$PWD/qdeclarativedebuggerstatus_p.h \
@@ -20,4 +23,8 @@ HEADERS += \
     $$PWD/qdeclarativedebugtrace_p.h \
     $$PWD/qdeclarativedebughelper_p.h \
     $$PWD/qdeclarativedebugserver_p.h \
-    debugger/qdeclarativedebugserverconnection_p.h
+    $$PWD/qdeclarativedebugserverconnection_p.h \
+    $$PWD/qdeclarativeobserverservice_p.h \
+    $$PWD/qdeclarativeobserverinterface_p.h \
+    $$PWD/qjsdebuggeragent_p.h \
+    $$PWD/qjsdebugservice_p.h
diff --git a/src/declarative/debugger/qdeclarativedebugserver.cpp b/src/declarative/debugger/qdeclarativedebugserver.cpp
index 5112af0..4343870 100644
--- a/src/declarative/debugger/qdeclarativedebugserver.cpp
+++ b/src/declarative/debugger/qdeclarativedebugserver.cpp
@@ -90,7 +90,11 @@ public:
     QHash<QString, QDeclarativeDebugService *> plugins;
     QStringList clientPlugins;
     bool gotHello;
+    QString waitingForMsgFromService;
 
+private:
+    // private slot
+    void _q_deliverMessage(const QString &serviceName, const QByteArray &message);
     static QDeclarativeDebugServerConnection *loadConnectionPlugin(const QString &pluginName);
 };
 
@@ -237,7 +241,6 @@ void QDeclarativeDebugServer::receiveMessage(const QByteArray &message)
 
     QDataStream in(message);
     if (!d->gotHello) {
-
         QString name;
         int op;
         in >> name >> op;
@@ -252,6 +255,17 @@ void QDeclarativeDebugServer::receiveMessage(const QByteArray &message)
         int version;
         in >> version >> d->clientPlugins;
 
+        // Send the hello answer immediately, since it needs to arrive before
+        // the plugins below start sending messages.
+        QByteArray helloAnswer;
+        {
+            QDataStream out(&helloAnswer, QIODevice::WriteOnly);
+            out << QString(QLatin1String("QDeclarativeDebugClient")) << 0 << protocolVersion << d->plugins.keys();
+        }
+        d->connection->send(helloAnswer);
+
+        d->gotHello = true;
+
         QHash<QString, QDeclarativeDebugService*>::Iterator iter = d->plugins.begin();
         for (; iter != d->plugins.end(); ++iter) {
             QDeclarativeDebugService::Status newStatus = QDeclarativeDebugService::Unavailable;
@@ -261,14 +275,6 @@ void QDeclarativeDebugServer::receiveMessage(const QByteArray &message)
             iter.value()->statusChanged(newStatus);
         }
 
-        QByteArray helloAnswer;
-        {
-            QDataStream out(&helloAnswer, QIODevice::WriteOnly);
-            out << QString(QLatin1String("QDeclarativeDebugClient")) << 0 << protocolVersion << d->plugins.keys();
-        }
-        d->connection->send(helloAnswer);
-
-        d->gotHello = true;
         qWarning("QDeclarativeDebugServer: Connection established");
     } else {
 
@@ -306,17 +312,33 @@ void QDeclarativeDebugServer::receiveMessage(const QByteArray &message)
             QByteArray message;
             in >> message;
 
-            QHash<QString, QDeclarativeDebugService *>::Iterator iter =
-                d->plugins.find(name);
-            if (iter == d->plugins.end()) {
-                qWarning() << "QDeclarativeDebugServer: Message received for missing plugin" << name;
+            if (d->waitingForMsgFromService == name) {
+                // deliver directly so that it is delivered before waitForMessage is returning.
+                d->_q_deliverMessage(name, message);
+                d->waitingForMsgFromService.clear();
             } else {
-                (*iter)->messageReceived(message);
+                // deliver message in next event loop run.
+                // Fixes the case that the service does start it's own event loop ...,
+                // but the networking code doesn't deliver any new messages because readyRead
+                // hasn't returned.
+                QMetaObject::invokeMethod(this, "_q_deliverMessage", Qt::QueuedConnection,
+                                          Q_ARG(QString, name),
+                                          Q_ARG(QByteArray, message));
             }
         }
     }
 }
 
+void QDeclarativeDebugServerPrivate::_q_deliverMessage(const QString &serviceName, const QByteArray &message)
+{
+    QHash<QString, QDeclarativeDebugService *>::Iterator iter = plugins.find(serviceName);
+    if (iter == plugins.end()) {
+        qWarning() << "QDeclarativeDebugServer: Message received for missing plugin" << serviceName;
+    } else {
+        (*iter)->messageReceived(message);
+    }
+}
+
 QList<QDeclarativeDebugService*> QDeclarativeDebugServer::services() const
 {
     const Q_D(QDeclarativeDebugServer);
@@ -374,4 +396,23 @@ void QDeclarativeDebugServer::sendMessage(QDeclarativeDebugService *service,
     d->connection->send(msg);
 }
 
+bool QDeclarativeDebugServer::waitForMessage(QDeclarativeDebugService *service)
+{
+    Q_D(QDeclarativeDebugServer);
+
+    if (!service
+            || !d->plugins.contains(service->name())
+            || !d->waitingForMsgFromService.isEmpty())
+        return false;
+
+    d->waitingForMsgFromService = service->name();
+
+    do {
+        d->connection->waitForMessage();
+    } while (!d->waitingForMsgFromService.isEmpty());
+    return true;
+}
+
 QT_END_NAMESPACE
+
+#include "moc_qdeclarativedebugserver_p.cpp"
diff --git a/src/declarative/debugger/qdeclarativedebugserver_p.h b/src/declarative/debugger/qdeclarativedebugserver_p.h
index 68ea4d8..72c664c 100644
--- a/src/declarative/debugger/qdeclarativedebugserver_p.h
+++ b/src/declarative/debugger/qdeclarativedebugserver_p.h
@@ -75,10 +75,13 @@ public:
     void sendMessage(QDeclarativeDebugService *service, const QByteArray &message);
     void receiveMessage(const QByteArray &message);
 
+    bool waitForMessage(QDeclarativeDebugService *service);
+
 private:
     friend class QDeclarativeDebugService;
     friend class QDeclarativeDebugServicePrivate;
     QDeclarativeDebugServer();
+    Q_PRIVATE_SLOT(d_func(), void _q_deliverMessage(QString, QByteArray))
 };
 
 QT_END_NAMESPACE
diff --git a/src/declarative/debugger/qdeclarativedebugserverconnection_p.h b/src/declarative/debugger/qdeclarativedebugserverconnection_p.h
index 0c2bdb4..ca267e0 100644
--- a/src/declarative/debugger/qdeclarativedebugserverconnection_p.h
+++ b/src/declarative/debugger/qdeclarativedebugserverconnection_p.h
@@ -62,6 +62,7 @@ public:
     virtual bool isConnected() const = 0;
     virtual void send(const QByteArray &message) = 0;
     virtual void disconnect() = 0;
+    virtual bool waitForMessage() = 0;
 };
 
 Q_DECLARE_INTERFACE(QDeclarativeDebugServerConnection, "com.trolltech.Qt.QDeclarativeDebugServerConnection/1.0")
diff --git a/src/declarative/debugger/qdeclarativedebugservice.cpp b/src/declarative/debugger/qdeclarativedebugservice.cpp
index 1b39f1c..c7e6615 100644
--- a/src/declarative/debugger/qdeclarativedebugservice.cpp
+++ b/src/declarative/debugger/qdeclarativedebugservice.cpp
@@ -209,6 +209,16 @@ void QDeclarativeDebugService::sendMessage(const QByteArray &message)
     d->server->sendMessage(this, message);
 }
 
+bool QDeclarativeDebugService::waitForMessage()
+{
+    Q_D(QDeclarativeDebugService);
+
+    if (status() != Enabled)
+        return false;
+
+    return d->server->waitForMessage(this);
+}
+
 void QDeclarativeDebugService::statusChanged(Status)
 {
 }
diff --git a/src/declarative/debugger/qdeclarativedebugservice_p.h b/src/declarative/debugger/qdeclarativedebugservice_p.h
index 5e30350..f3d1919 100644
--- a/src/declarative/debugger/qdeclarativedebugservice_p.h
+++ b/src/declarative/debugger/qdeclarativedebugservice_p.h
@@ -69,6 +69,7 @@ public:
     Status status() const;
 
     void sendMessage(const QByteArray &);
+    bool waitForMessage();
 
     static int idForObject(QObject *);
     static QObject *objectForId(int);
@@ -84,6 +85,7 @@ protected:
 
 private:
     friend class QDeclarativeDebugServer;
+    friend class QDeclarativeDebugServerPrivate;
 };
 
 QT_END_NAMESPACE
diff --git a/src/declarative/debugger/qdeclarativedebugtrace.cpp b/src/declarative/debugger/qdeclarativedebugtrace.cpp
index 6f28736..edbbe78 100644
--- a/src/declarative/debugger/qdeclarativedebugtrace.cpp
+++ b/src/declarative/debugger/qdeclarativedebugtrace.cpp
@@ -65,9 +65,14 @@ QByteArray QDeclarativeDebugData::toByteArray() const
 
 QDeclarativeDebugTrace::QDeclarativeDebugTrace()
 : QDeclarativeDebugService(QLatin1String("CanvasFrameRate")),
-  m_enabled(false), m_deferredSend(true)
+  m_enabled(false), m_deferredSend(true), m_messageReceived(false)
 {
     m_timer.start();
+    if (status() == Enabled) {
+        // wait for first message indicating whether to trace or not
+        while (!m_messageReceived)
+            waitForMessage();
+    }
 }
 
 void QDeclarativeDebugTrace::addEvent(EventType t)
@@ -213,6 +218,8 @@ void QDeclarativeDebugTrace::messageReceived(const QByteArray &message)
 
     stream >> m_enabled;
 
+    m_messageReceived = true;
+
     if (!m_enabled)
         sendMessages();
 }
diff --git a/src/declarative/debugger/qdeclarativedebugtrace_p.h b/src/declarative/debugger/qdeclarativedebugtrace_p.h
index ae0653e..c74cbe0 100644
--- a/src/declarative/debugger/qdeclarativedebugtrace_p.h
+++ b/src/declarative/debugger/qdeclarativedebugtrace_p.h
@@ -120,6 +120,7 @@ private:
     QPerformanceTimer m_timer;
     bool m_enabled;
     bool m_deferredSend;
+    bool m_messageReceived;
     QList<QDeclarativeDebugData> m_data;
 };
 
diff --git a/src/declarative/debugger/qdeclarativeobserverinterface_p.h b/src/declarative/debugger/qdeclarativeobserverinterface_p.h
new file mode 100644
index 0000000..501c132
--- /dev/null
+++ b/src/declarative/debugger/qdeclarativeobserverinterface_p.h
@@ -0,0 +1,69 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QDECLARATIVEOBSERVERINTERFACE_H
+#define QDECLARATIVEOBSERVERINTERFACE_H
+
+#include <QtDeclarative/private/qdeclarativeglobal_p.h>
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Declarative)
+
+class Q_DECLARATIVE_EXPORT QDeclarativeObserverInterface
+{
+public:
+    QDeclarativeObserverInterface() {}
+    virtual ~QDeclarativeObserverInterface() {}
+
+    virtual void activate() = 0;
+    virtual void deactivate() = 0;
+};
+
+Q_DECLARE_INTERFACE(QDeclarativeObserverInterface, "com.trolltech.Qt.QDeclarativeObserverInterface/1.0")
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif // QDECLARATIVEOBSERVERINTERFACE_H
diff --git a/src/declarative/debugger/qdeclarativeobserverservice.cpp b/src/declarative/debugger/qdeclarativeobserverservice.cpp
new file mode 100644
index 0000000..a623c55
--- /dev/null
+++ b/src/declarative/debugger/qdeclarativeobserverservice.cpp
@@ -0,0 +1,137 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "private/qdeclarativeobserverservice_p.h"
+#include "private/qdeclarativeobserverinterface_p.h"
+
+#include <QtCore/QCoreApplication>
+#include <QtCore/QDebug>
+#include <QtCore/QDir>
+#include <QtCore/QPluginLoader>
+
+#include <QtDeclarative/QDeclarativeView>
+
+QT_BEGIN_NAMESPACE
+
+Q_GLOBAL_STATIC(QDeclarativeObserverService, serviceInstance)
+
+QDeclarativeObserverService::QDeclarativeObserverService()
+    : QDeclarativeDebugService(QLatin1String("QDeclarativeObserverMode"))
+    , m_observer(0)
+{
+}
+
+QDeclarativeObserverService *QDeclarativeObserverService::instance()
+{
+    return serviceInstance();
+}
+
+void QDeclarativeObserverService::addView(QDeclarativeView *view)
+{
+    m_views.append(view);
+}
+
+void QDeclarativeObserverService::removeView(QDeclarativeView *view)
+{
+    m_views.removeAll(view);
+}
+
+void QDeclarativeObserverService::sendMessage(const QByteArray &message)
+{
+    if (status() != Enabled)
+        return;
+
+    QDeclarativeDebugService::sendMessage(message);
+}
+
+void QDeclarativeObserverService::statusChanged(Status status)
+{
+    if (m_views.isEmpty())
+        return;
+
+    if (status == Enabled) {
+        if (!m_observer)
+            m_observer = loadObserverPlugin();
+
+        if (!m_observer) {
+            qWarning() << "Error while loading observer plugin";
+            return;
+        }
+
+        m_observer->activate();
+    } else {
+        if (m_observer)
+            m_observer->deactivate();
+    }
+}
+
+void QDeclarativeObserverService::messageReceived(const QByteArray &message)
+{
+    emit gotMessage(message);
+}
+
+QDeclarativeObserverInterface *QDeclarativeObserverService::loadObserverPlugin()
+{
+    QStringList pluginCandidates;
+    const QStringList paths = QCoreApplication::libraryPaths();
+    foreach (const QString &libPath, paths) {
+        const QDir dir(libPath + QLatin1String("/qmltooling"));
+        if (dir.exists())
+            foreach (const QString &pluginPath, dir.entryList(QDir::Files))
+                pluginCandidates << dir.absoluteFilePath(pluginPath);
+    }
+
+    foreach (const QString &pluginPath, pluginCandidates) {
+        QPluginLoader loader(pluginPath);
+        if (!loader.load())
+            continue;
+
+        QDeclarativeObserverInterface *observer =
+                qobject_cast<QDeclarativeObserverInterface*>(loader.instance());
+
+        if (observer)
+            return observer;
+        loader.unload();
+    }
+    return 0;
+}
+
+QT_END_NAMESPACE
diff --git a/src/declarative/debugger/qdeclarativeobserverservice_p.h b/src/declarative/debugger/qdeclarativeobserverservice_p.h
new file mode 100644
index 0000000..36f31dc
--- /dev/null
+++ b/src/declarative/debugger/qdeclarativeobserverservice_p.h
@@ -0,0 +1,91 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QDECLARATIVEOBSERVERSERVICE_H
+#define QDECLARATIVEOBSERVERSERVICE_H
+
+#include "private/qdeclarativedebugservice_p.h"
+#include <private/qdeclarativeglobal_p.h>
+
+#include <QtCore/QList>
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Declarative)
+
+class QDeclarativeView;
+class QDeclarativeObserverInterface;
+
+class Q_DECLARATIVE_EXPORT QDeclarativeObserverService : public QDeclarativeDebugService
+{
+    Q_OBJECT
+
+public:
+    QDeclarativeObserverService();
+    static QDeclarativeObserverService *instance();
+
+    void addView(QDeclarativeView *);
+    void removeView(QDeclarativeView *);
+    QList<QDeclarativeView*> views() const { return m_views; }
+
+    void sendMessage(const QByteArray &message);
+
+Q_SIGNALS:
+    void gotMessage(const QByteArray &message);
+
+protected:
+    virtual void statusChanged(Status status);
+    virtual void messageReceived(const QByteArray &);
+
+private:
+    static QDeclarativeObserverInterface *loadObserverPlugin();
+
+    QList<QDeclarativeView*> m_views;
+    QDeclarativeObserverInterface *m_observer;
+};
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif // QDECLARATIVEOBSERVERSERVICE_H
diff --git a/src/declarative/debugger/qjsdebuggeragent.cpp b/src/declarative/debugger/qjsdebuggeragent.cpp
new file mode 100644
index 0000000..601c8c8
--- /dev/null
+++ b/src/declarative/debugger/qjsdebuggeragent.cpp
@@ -0,0 +1,576 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "private/qjsdebuggeragent_p.h"
+#include "private/qdeclarativedebughelper_p.h"
+
+#include <QtCore/qdatetime.h>
+#include <QtCore/qcoreapplication.h>
+#include <QtCore/qset.h>
+#include <QtCore/qurl.h>
+#include <QtScript/qscriptcontextinfo.h>
+#include <QtScript/qscriptengine.h>
+#include <QtScript/qscriptvalueiterator.h>
+
+QT_BEGIN_NAMESPACE
+
+class QJSDebuggerAgentPrivate
+{
+public:
+    QJSDebuggerAgentPrivate(QJSDebuggerAgent *q)
+        : q(q), state(NoState)
+    {}
+
+    void continueExec();
+    void recordKnownObjects(const QList<JSAgentWatchData> &);
+    QList<JSAgentWatchData> getLocals(QScriptContext *);
+    void positionChange(qint64 scriptId, int lineNumber, int columnNumber);
+    QScriptEngine *engine() { return q->engine(); }
+    void stopped();
+
+public:
+    QJSDebuggerAgent *q;
+    JSDebuggerState state;
+    int stepDepth;
+    int stepCount;
+
+    QEventLoop loop;
+    QHash<qint64, QString> filenames;
+    JSAgentBreakpoints breakpoints;
+    // breakpoints by filename (without path)
+    QHash<QString, JSAgentBreakpointData> fileNameToBreakpoints;
+    QStringList watchExpressions;
+    QSet<qint64> knownObjectIds;
+};
+
+namespace {
+
+class SetupExecEnv
+{
+public:
+    SetupExecEnv(QJSDebuggerAgentPrivate *a)
+        : agent(a),
+          previousState(a->state),
+          hadException(a->engine()->hasUncaughtException())
+    {
+        agent->state = StoppedState;
+    }
+
+    ~SetupExecEnv()
+    {
+        if (!hadException && agent->engine()->hasUncaughtException())
+            agent->engine()->clearExceptions();
+        agent->state = previousState;
+    }
+
+private:
+    QJSDebuggerAgentPrivate *agent;
+    JSDebuggerState previousState;
+    bool hadException;
+};
+
+} // anonymous namespace
+
+static JSAgentWatchData fromScriptValue(const QString &expression,
+                                        const QScriptValue &value)
+{
+    static const QString arrayStr = QCoreApplication::translate
+            ("Debugger::JSAgentWatchData", "[Array of length %1]");
+    static const QString undefinedStr = QCoreApplication::translate
+            ("Debugger::JSAgentWatchData", "<undefined>");
+
+    JSAgentWatchData data;
+    data.exp = expression.toUtf8();
+    data.name = data.exp;
+    data.hasChildren = false;
+    data.value = value.toString().toUtf8();
+    data.objectId = value.objectId();
+    if (value.isArray()) {
+        data.type = "Array";
+        data.value = arrayStr.arg(value.property(QLatin1String("length")).toString()).toUtf8();
+        data.hasChildren = true;
+    } else if (value.isBool()) {
+        data.type = "Bool";
+        // data.value = value.toBool() ? "true" : "false";
+    } else if (value.isDate()) {
+        data.type = "Date";
+        data.value = value.toDateTime().toString().toUtf8();
+    } else if (value.isError()) {
+        data.type = "Error";
+    } else if (value.isFunction()) {
+        data.type = "Function";
+    } else if (value.isUndefined()) {
+        data.type = undefinedStr.toUtf8();
+    } else if (value.isNumber()) {
+        data.type = "Number";
+    } else if (value.isRegExp()) {
+        data.type = "RegExp";
+    } else if (value.isString()) {
+        data.type = "String";
+    } else if (value.isVariant()) {
+        data.type = "Variant";
+    } else if (value.isQObject()) {
+        const QObject *obj = value.toQObject();
+        data.type = "Object";
+        data.value += '[';
+        data.value += obj->metaObject()->className();
+        data.value += ']';
+        data.hasChildren = true;
+    } else if (value.isObject()) {
+        data.type = "Object";
+        data.hasChildren = true;
+        data.value = "[Object]";
+    } else if (value.isNull()) {
+        data.type = "<null>";
+    } else {
+        data.type = "<unknown>";
+    }
+    return data;
+}
+
+static QList<JSAgentWatchData> expandObject(const QScriptValue &object)
+{
+    QList<JSAgentWatchData> result;
+    QScriptValueIterator it(object);
+    while (it.hasNext()) {
+        it.next();
+        if (it.flags() & QScriptValue::SkipInEnumeration)
+            continue;
+        if (/*object.isQObject() &&*/ it.value().isFunction()) {
+            // Cosmetics: skip all functions and slot, there are too many of them,
+            // and it is not useful information in the debugger.
+            continue;
+        }
+        JSAgentWatchData data = fromScriptValue(it.name(), it.value());
+        result.append(data);
+    }
+    if (result.isEmpty()) {
+        JSAgentWatchData data;
+        data.name = "<no initialized data>";
+        data.hasChildren = false;
+        data.value = " ";
+        data.objectId = 0;
+        result.append(data);
+    }
+    return result;
+}
+
+static QString fileName(const QString &fileUrl)
+{
+    int lastDelimiterPos = fileUrl.lastIndexOf(QLatin1Char('/'));
+    return fileUrl.mid(lastDelimiterPos, fileUrl.size() - lastDelimiterPos);
+}
+
+void QJSDebuggerAgentPrivate::recordKnownObjects(const QList<JSAgentWatchData>& list)
+{
+    foreach (const JSAgentWatchData &data, list)
+        knownObjectIds << data.objectId;
+}
+
+QList<JSAgentWatchData> QJSDebuggerAgentPrivate::getLocals(QScriptContext *ctx)
+{
+    QList<JSAgentWatchData> locals;
+    if (ctx) {
+        QScriptValue activationObject = ctx->activationObject();
+        QScriptValue thisObject = ctx->thisObject();
+        locals = expandObject(activationObject);
+        if (thisObject.isObject()
+                && thisObject.objectId() != engine()->globalObject().objectId()
+                && QScriptValueIterator(thisObject).hasNext())
+            locals.prepend(fromScriptValue(QLatin1String("this"), thisObject));
+        recordKnownObjects(locals);
+        knownObjectIds << activationObject.objectId();
+    }
+    return locals;
+}
+
+/*!
+  Constructs a new agent for the given \a engine. The agent will
+  report debugging-related events (e.g. step completion) to the given
+  \a backend.
+*/
+QJSDebuggerAgent::QJSDebuggerAgent(QScriptEngine *engine, QObject *parent)
+    : QObject(parent)
+    , QScriptEngineAgent(engine)
+    , d(new QJSDebuggerAgentPrivate(this))
+{
+    QJSDebuggerAgent::engine()->setAgent(this);
+}
+
+QJSDebuggerAgent::QJSDebuggerAgent(QDeclarativeEngine *engine, QObject *parent)
+    : QObject(parent)
+    , QScriptEngineAgent(QDeclarativeDebugHelper::getScriptEngine(engine))
+    , d(new QJSDebuggerAgentPrivate(this))
+{
+    QJSDebuggerAgent::engine()->setAgent(this);
+}
+
+/*!
+  Destroys this QJSDebuggerAgent.
+*/
+QJSDebuggerAgent::~QJSDebuggerAgent()
+{
+    engine()->setAgent(0);
+    delete d;
+}
+
+void QJSDebuggerAgent::setBreakpoints(const JSAgentBreakpoints &breakpoints)
+{
+    d->breakpoints = breakpoints;
+
+    d->fileNameToBreakpoints.clear();
+    foreach (const JSAgentBreakpointData &bp, breakpoints)
+        d->fileNameToBreakpoints.insertMulti(fileName(QString::fromUtf8(bp.fileUrl)), bp);
+}
+
+void QJSDebuggerAgent::setWatchExpressions(const QStringList &watchExpressions)
+{
+    d->watchExpressions = watchExpressions;
+}
+
+void QJSDebuggerAgent::stepOver()
+{
+    d->stepDepth = 0;
+    d->state = SteppingOverState;
+    d->continueExec();
+}
+
+void QJSDebuggerAgent::stepInto()
+{
+    d->stepDepth = 0;
+    d->state = SteppingIntoState;
+    d->continueExec();
+}
+
+void QJSDebuggerAgent::stepOut()
+{
+    d->stepDepth = 0;
+    d->state = SteppingOutState;
+    d->continueExec();
+}
+
+void QJSDebuggerAgent::continueExecution()
+{
+    d->state = NoState;
+    d->continueExec();
+}
+
+JSAgentWatchData QJSDebuggerAgent::executeExpression(const QString &expr)
+{
+    SetupExecEnv execEnv(d);
+
+    JSAgentWatchData data = fromScriptValue(expr, engine()->evaluate(expr));
+    d->knownObjectIds << data.objectId;
+    return data;
+}
+
+QList<JSAgentWatchData> QJSDebuggerAgent::expandObjectById(quint64 objectId)
+{
+    SetupExecEnv execEnv(d);
+
+    QScriptValue v;
+    if (d->knownObjectIds.contains(objectId))
+        v = engine()->objectById(objectId);
+
+    QList<JSAgentWatchData> result = expandObject(v);
+    d->recordKnownObjects(result);
+    return result;
+}
+
+QList<JSAgentWatchData> QJSDebuggerAgent::locals()
+{
+    SetupExecEnv execEnv(d);
+    return d->getLocals(engine()->currentContext());
+}
+
+QList<JSAgentWatchData> QJSDebuggerAgent::localsAtFrame(int frameId)
+{
+    SetupExecEnv execEnv(d);
+
+    int deep = 0;
+    QScriptContext *ctx = engine()->currentContext();
+    while (ctx && deep < frameId) {
+        ctx = ctx->parentContext();
+        deep++;
+    }
+
+    return d->getLocals(ctx);
+}
+
+QList<JSAgentStackData> QJSDebuggerAgent::backtrace()
+{
+    SetupExecEnv execEnv(d);
+
+    QList<JSAgentStackData> backtrace;
+
+    for (QScriptContext *ctx = engine()->currentContext(); ctx; ctx = ctx->parentContext()) {
+        QScriptContextInfo info(ctx);
+
+        JSAgentStackData frame;
+        frame.functionName = info.functionName().toUtf8();
+        if (frame.functionName.isEmpty()) {
+            if (ctx->parentContext()) {
+                switch (info.functionType()) {
+                case QScriptContextInfo::ScriptFunction:
+                    frame.functionName = "<anonymous>";
+                    break;
+                case QScriptContextInfo::NativeFunction:
+                    frame.functionName = "<native>";
+                    break;
+                case QScriptContextInfo::QtFunction:
+                case QScriptContextInfo::QtPropertyFunction:
+                    frame.functionName = "<native slot>";
+                    break;
+                }
+            } else {
+                frame.functionName = "<global>";
+            }
+        }
+        frame.lineNumber = info.lineNumber();
+        // if the line number is unknown, fallback to the function line number
+        if (frame.lineNumber == -1)
+            frame.lineNumber = info.functionStartLineNumber();
+
+        frame.fileUrl = info.fileName().toUtf8();
+        backtrace.append(frame);
+    }
+
+    return backtrace;
+}
+
+QList<JSAgentWatchData> QJSDebuggerAgent::watches()
+{
+    SetupExecEnv execEnv(d);
+
+    QList<JSAgentWatchData> watches;
+    foreach (const QString &expr, d->watchExpressions)
+        watches << fromScriptValue(expr, engine()->evaluate(expr));
+    d->recordKnownObjects(watches);
+    return watches;
+}
+
+void QJSDebuggerAgent::setProperty(qint64 objectId,
+                                   const QString &property,
+                                   const QString &value)
+{
+    SetupExecEnv execEnv(d);
+
+    if (d->knownObjectIds.contains(objectId)) {
+        QScriptValue object = engine()->objectById(objectId);
+        if (object.isObject()) {
+            QScriptValue result = engine()->evaluate(value);
+            object.setProperty(property, result);
+        }
+    }
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::scriptLoad(qint64 id, const QString &program,
+                                  const QString &fileName, int)
+{
+    Q_UNUSED(program);
+    d->filenames.insert(id, fileName);
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::scriptUnload(qint64 id)
+{
+    d->filenames.remove(id);
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::contextPush()
+{
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::contextPop()
+{
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::functionEntry(qint64 scriptId)
+{
+    Q_UNUSED(scriptId);
+    d->stepDepth++;
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::functionExit(qint64 scriptId, const QScriptValue &returnValue)
+{
+    Q_UNUSED(scriptId);
+    Q_UNUSED(returnValue);
+    d->stepDepth--;
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::positionChange(qint64 scriptId, int lineNumber, int columnNumber)
+{
+    d->positionChange(scriptId, lineNumber, columnNumber);
+}
+
+void QJSDebuggerAgentPrivate::positionChange(qint64 scriptId, int lineNumber, int columnNumber)
+{
+    Q_UNUSED(columnNumber);
+
+    if (state == StoppedState)
+        return; //no re-entrency
+
+    // check breakpoints
+    if (!breakpoints.isEmpty()) {
+        QHash<qint64, QString>::const_iterator it = filenames.constFind(scriptId);
+        QScriptContext *ctx = engine()->currentContext();
+        QScriptContextInfo info(ctx);
+        if (it == filenames.constEnd()) {
+            // It is possible that the scripts are loaded before the agent is attached
+            QString filename = info.fileName();
+
+            JSAgentStackData frame;
+            frame.functionName = info.functionName().toUtf8();
+
+            QPair<QString, qint32> key = qMakePair(filename, lineNumber);
+            it = filenames.insert(scriptId, filename);
+        }
+
+        const QString filePath = it.value();
+        JSAgentBreakpoints bps = fileNameToBreakpoints.values(fileName(filePath)).toSet();
+
+        foreach (const JSAgentBreakpointData &bp, bps) {
+            if (bp.lineNumber == lineNumber) {
+                stopped();
+                return;
+            }
+        }
+    }
+
+    switch (state) {
+    case NoState:
+    case StoppedState:
+        // Do nothing
+        break;
+    case SteppingOutState:
+        if (stepDepth >= 0)
+            break;
+        //fallthough
+    case SteppingOverState:
+        if (stepDepth > 0)
+            break;
+        //fallthough
+    case SteppingIntoState:
+        stopped();
+        break;
+    }
+
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::exceptionThrow(qint64 scriptId,
+                                     const QScriptValue &exception,
+                                     bool hasHandler)
+{
+    Q_UNUSED(scriptId);
+    Q_UNUSED(exception);
+    Q_UNUSED(hasHandler);
+//    qDebug() << Q_FUNC_INFO << exception.toString() << hasHandler;
+#if 0 //sometimes, we get exceptions that we should just ignore.
+    if (!hasHandler && state != StoppedState)
+        stopped(true, exception);
+#endif
+}
+
+/*!
+  \reimp
+*/
+void QJSDebuggerAgent::exceptionCatch(qint64 scriptId, const QScriptValue &exception)
+{
+    Q_UNUSED(scriptId);
+    Q_UNUSED(exception);
+}
+
+bool QJSDebuggerAgent::supportsExtension(Extension extension) const
+{
+    return extension == QScriptEngineAgent::DebuggerInvocationRequest;
+}
+
+QVariant QJSDebuggerAgent::extension(Extension extension, const QVariant &argument)
+{
+    if (extension == QScriptEngineAgent::DebuggerInvocationRequest) {
+        d->stopped();
+        return QVariant();
+    }
+    return QScriptEngineAgent::extension(extension, argument);
+}
+
+void QJSDebuggerAgentPrivate::stopped()
+{
+    bool becauseOfException = false;
+    const QScriptValue &exception = QScriptValue();
+
+    knownObjectIds.clear();
+    state = StoppedState;
+
+    emit q->stopped(becauseOfException, exception.toString());
+
+    loop.exec(QEventLoop::ExcludeUserInputEvents);
+}
+
+void QJSDebuggerAgentPrivate::continueExec()
+{
+    loop.quit();
+}
+
+QT_END_NAMESPACE
diff --git a/src/declarative/debugger/qjsdebuggeragent_p.h b/src/declarative/debugger/qjsdebuggeragent_p.h
new file mode 100644
index 0000000..ce5a044
--- /dev/null
+++ b/src/declarative/debugger/qjsdebuggeragent_p.h
@@ -0,0 +1,204 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QJSDEBUGGERAGENT_P_H
+#define QJSDEBUGGERAGENT_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 <QtScript/qscriptengineagent.h>
+#include <QtCore/qset.h>
+
+QT_BEGIN_NAMESPACE
+class QScriptValue;
+class QDeclarativeEngine;
+QT_END_NAMESPACE
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Declarative)
+
+class QJSDebuggerAgentPrivate;
+
+enum JSDebuggerState
+{
+    NoState,
+    SteppingIntoState,
+    SteppingOverState,
+    SteppingOutState,
+    StoppedState
+};
+
+struct JSAgentWatchData
+{
+    QByteArray exp;
+    QByteArray name;
+    QByteArray value;
+    QByteArray type;
+    bool hasChildren;
+    quint64 objectId;
+};
+
+inline QDataStream &operator<<(QDataStream &s, const JSAgentWatchData &data)
+{
+    return s << data.exp << data.name << data.value
+             << data.type << data.hasChildren << data.objectId;
+}
+
+struct JSAgentStackData
+{
+    QByteArray functionName;
+    QByteArray fileUrl;
+    qint32 lineNumber;
+};
+
+inline QDataStream &operator<<(QDataStream &s, const JSAgentStackData &data)
+{
+    return s << data.functionName << data.fileUrl << data.lineNumber;
+}
+
+struct JSAgentBreakpointData
+{
+    QByteArray functionName;
+    QByteArray fileUrl;
+    qint32 lineNumber;
+};
+
+typedef QSet<JSAgentBreakpointData> JSAgentBreakpoints;
+
+inline QDataStream &operator<<(QDataStream &s, const JSAgentBreakpointData &data)
+{
+    return s << data.functionName << data.fileUrl << data.lineNumber;
+}
+
+inline QDataStream &operator>>(QDataStream &s, JSAgentBreakpointData &data)
+{
+    return s >> data.functionName >> data.fileUrl >> data.lineNumber;
+}
+
+inline bool operator==(const JSAgentBreakpointData &b1, const JSAgentBreakpointData &b2)
+{
+    return b1.lineNumber == b2.lineNumber && b1.fileUrl == b2.fileUrl;
+}
+
+inline uint qHash(const JSAgentBreakpointData &b)
+{
+    return b.lineNumber ^ qHash(b.fileUrl);
+}
+
+
+class QJSDebuggerAgent : public QObject, public QScriptEngineAgent
+{
+    Q_OBJECT
+
+public:
+    QJSDebuggerAgent(QScriptEngine *engine, QObject *parent = 0);
+    QJSDebuggerAgent(QDeclarativeEngine *engine, QObject *parent = 0);
+    ~QJSDebuggerAgent();
+
+    void setBreakpoints(const JSAgentBreakpoints &);
+    void setWatchExpressions(const QStringList &);
+
+    void stepOver();
+    void stepInto();
+    void stepOut();
+    void continueExecution();
+
+    JSAgentWatchData executeExpression(const QString &expr);
+    QList<JSAgentWatchData> expandObjectById(quint64 objectId);
+    QList<JSAgentWatchData> locals();
+    QList<JSAgentWatchData> localsAtFrame(int frameId);
+    QList<JSAgentStackData> backtrace();
+    QList<JSAgentWatchData> watches();
+    void setProperty(qint64 objectId,
+                     const QString &property,
+                     const QString &value);
+
+    // reimplemented
+    void scriptLoad(qint64 id, const QString &program,
+                    const QString &fileName, int baseLineNumber);
+    void scriptUnload(qint64 id);
+
+    void contextPush();
+    void contextPop();
+
+    void functionEntry(qint64 scriptId);
+    void functionExit(qint64 scriptId,
+                      const QScriptValue &returnValue);
+
+    void positionChange(qint64 scriptId,
+                        int lineNumber, int columnNumber);
+
+    void exceptionThrow(qint64 scriptId,
+                        const QScriptValue &exception,
+                        bool hasHandler);
+    void exceptionCatch(qint64 scriptId,
+                        const QScriptValue &exception);
+
+    bool supportsExtension(Extension extension) const;
+    QVariant extension(Extension extension,
+                       const QVariant &argument = QVariant());
+
+Q_SIGNALS:
+    void stopped(bool becauseOfException,
+                 const QString &exception);
+
+private:
+    friend class QJSDebuggerAgentPrivate;
+    QJSDebuggerAgentPrivate *d;
+};
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif // QJSDEBUGGERAGENT_P_H
diff --git a/src/declarative/debugger/qjsdebugservice.cpp b/src/declarative/debugger/qjsdebugservice.cpp
new file mode 100644
index 0000000..f8cd095
--- /dev/null
+++ b/src/declarative/debugger/qjsdebugservice.cpp
@@ -0,0 +1,198 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "private/qjsdebugservice_p.h"
+#include "private/qjsdebuggeragent_p.h"
+
+#include <QtCore/qdatastream.h>
+#include <QtCore/qdebug.h>
+#include <QtCore/qstringlist.h>
+#include <QtDeclarative/qdeclarativeengine.h>
+
+Q_GLOBAL_STATIC(QJSDebugService, serviceInstance)
+
+QJSDebugService::QJSDebugService(QObject *parent)
+    : QDeclarativeDebugService(QLatin1String("JSDebugger"), parent)
+    , m_agent(0)
+{
+}
+
+QJSDebugService::~QJSDebugService()
+{
+    delete m_agent;
+}
+
+QJSDebugService *QJSDebugService::instance()
+{
+    return serviceInstance();
+}
+
+void QJSDebugService::addEngine(QDeclarativeEngine *engine)
+{
+    Q_ASSERT(engine);
+    Q_ASSERT(!m_engines.contains(engine));
+
+    m_engines.append(engine);
+}
+
+void QJSDebugService::removeEngine(QDeclarativeEngine *engine)
+{
+    Q_ASSERT(engine);
+    Q_ASSERT(m_engines.contains(engine));
+
+    m_engines.removeAll(engine);
+}
+
+void QJSDebugService::statusChanged(Status status)
+{
+    if (status == Enabled && !m_engines.isEmpty() && !m_agent) {
+        // Multiple engines are currently unsupported
+        QDeclarativeEngine *engine = m_engines.first();
+        m_agent = new QJSDebuggerAgent(engine, engine);
+
+        connect(m_agent, SIGNAL(stopped(bool,QString)),
+                this, SLOT(executionStopped(bool,QString)));
+
+    } else if (status != Enabled && m_agent) {
+        delete m_agent;
+        m_agent = 0;
+    }
+}
+
+void QJSDebugService::messageReceived(const QByteArray &message)
+{
+    if (!m_agent) {
+        qWarning() << "QJSDebugService::messageReceived: No QJSDebuggerAgent available";
+        return;
+    }
+
+    QDataStream ds(message);
+    QByteArray command;
+    ds >> command;
+    if (command == "BREAKPOINTS") {
+        JSAgentBreakpoints breakpoints;
+        ds >> breakpoints;
+        m_agent->setBreakpoints(breakpoints);
+
+        //qDebug() << "BREAKPOINTS";
+        //foreach (const JSAgentBreakpointData &bp, breakpoints)
+        //    qDebug() << "BREAKPOINT: " << bp.fileUrl << bp.lineNumber;
+    } else if (command == "WATCH_EXPRESSIONS") {
+        QStringList watchExpressions;
+        ds >> watchExpressions;
+        m_agent->setWatchExpressions(watchExpressions);
+    } else if (command == "STEPOVER") {
+        m_agent->stepOver();
+    } else if (command == "STEPINTO" || command == "INTERRUPT") {
+        m_agent->stepInto();
+    } else if (command == "STEPOUT") {
+        m_agent->stepOut();
+    } else if (command == "CONTINUE") {
+        m_agent->continueExecution();
+    } else if (command == "EXEC") {
+        QByteArray id;
+        QString expr;
+        ds >> id >> expr;
+
+        JSAgentWatchData data = m_agent->executeExpression(expr);
+
+        QByteArray reply;
+        QDataStream rs(&reply, QIODevice::WriteOnly);
+        rs << QByteArray("RESULT") << id << data;
+        sendMessage(reply);
+    } else if (command == "EXPAND") {
+        QByteArray requestId;
+        quint64 objectId;
+        ds >> requestId >> objectId;
+
+        QList<JSAgentWatchData> result = m_agent->expandObjectById(objectId);
+
+        QByteArray reply;
+        QDataStream rs(&reply, QIODevice::WriteOnly);
+        rs << QByteArray("EXPANDED") << requestId << result;
+        sendMessage(reply);
+    } else if (command == "ACTIVATE_FRAME") {
+        int frameId;
+        ds >> frameId;
+
+        QList<JSAgentWatchData> locals = m_agent->localsAtFrame(frameId);
+
+        QByteArray reply;
+        QDataStream rs(&reply, QIODevice::WriteOnly);
+        rs << QByteArray("LOCALS") << frameId << locals;
+        sendMessage(reply);
+    } else if (command == "SET_PROPERTY") {
+        QByteArray id;
+        qint64 objectId;
+        QString property;
+        QString value;
+        ds >> id >> objectId >> property >> value;
+
+        m_agent->setProperty(objectId, property, value);
+
+        //TODO: feedback
+    } else if (command == "PING") {
+        int ping;
+        ds >> ping;
+        QByteArray reply;
+        QDataStream rs(&reply, QIODevice::WriteOnly);
+        rs << QByteArray("PONG") << ping;
+        sendMessage(reply);
+    } else {
+        qDebug() << Q_FUNC_INFO << "Unknown command" << command;
+    }
+
+    QDeclarativeDebugService::messageReceived(message);
+}
+
+void QJSDebugService::executionStopped(bool becauseOfException,
+                                       const QString &exception)
+{
+    const QList<JSAgentStackData> backtrace = m_agent->backtrace();
+    const QList<JSAgentWatchData> watches = m_agent->watches();
+    const QList<JSAgentWatchData> locals = m_agent->locals();
+
+    QByteArray reply;
+    QDataStream rs(&reply, QIODevice::WriteOnly);
+    rs << QByteArray("STOPPED") << backtrace << watches << locals
+       << becauseOfException << exception;
+    sendMessage(reply);
+}
diff --git a/src/declarative/debugger/qjsdebugservice_p.h b/src/declarative/debugger/qjsdebugservice_p.h
new file mode 100644
index 0000000..6839ca8
--- /dev/null
+++ b/src/declarative/debugger/qjsdebugservice_p.h
@@ -0,0 +1,99 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QJSDEBUGSERVICE_P_H
+#define QJSDEBUGSERVICE_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/QPointer>
+
+#include "private/qdeclarativedebugservice_p.h"
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Declarative)
+
+class QDeclarativeEngine;
+class QJSDebuggerAgent;
+
+class QJSDebugService : public QDeclarativeDebugService
+{
+    Q_OBJECT
+
+public:
+    QJSDebugService(QObject *parent = 0);
+    ~QJSDebugService();
+
+    static QJSDebugService *instance();
+
+    void addEngine(QDeclarativeEngine *);
+    void removeEngine(QDeclarativeEngine *);
+
+protected:
+    void statusChanged(Status status);
+    void messageReceived(const QByteArray &);
+
+private Q_SLOTS:
+    void executionStopped(bool becauseOfException,
+                          const QString &exception);
+
+private:
+    QList<QDeclarativeEngine *> m_engines;
+    QPointer<QJSDebuggerAgent> m_agent;
+};
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif // QJSDEBUGSERVICE_P_H
diff --git a/src/declarative/debugger/qpacketprotocol.cpp b/src/declarative/debugger/qpacketprotocol.cpp
index 15a14cf..c1034a7 100644
--- a/src/declarative/debugger/qpacketprotocol.cpp
+++ b/src/declarative/debugger/qpacketprotocol.cpp
@@ -42,6 +42,7 @@
 #include "private/qpacketprotocol_p.h"
 
 #include <QBuffer>
+#include <QElapsedTimer>
 
 QT_BEGIN_NAMESPACE
 
@@ -114,7 +115,7 @@ Q_OBJECT
 public:
     QPacketProtocolPrivate(QPacketProtocol * parent, QIODevice * _dev)
     : QObject(parent), inProgressSize(-1), maxPacketSize(MAX_PACKET_SIZE),
-      dev(_dev)
+      waitingForPacket(false), dev(_dev)
     {
         Q_ASSERT(4 == sizeof(qint32));
 
@@ -125,7 +126,7 @@ public:
         QObject::connect(this, SIGNAL(invalidPacket()),
                          parent, SIGNAL(invalidPacket()));
         QObject::connect(dev, SIGNAL(readyRead()),
-                         this, SLOT(readyToRead()), Qt::QueuedConnection);
+                         this, SLOT(readyToRead()));
         QObject::connect(dev, SIGNAL(aboutToClose()),
                          this, SLOT(aboutToClose()));
         QObject::connect(dev, SIGNAL(bytesWritten(qint64)),
@@ -200,6 +201,7 @@ public Q_SLOTS:
                 inProgress.clear();
 
                 emit readyRead();
+                waitingForPacket = false;
 
                 // Need to get trailing data
                 readyToRead();
@@ -213,6 +215,7 @@ public:
     QByteArray inProgress;
     qint32 inProgressSize;
     qint32 maxPacketSize;
+    bool waitingForPacket;
     QIODevice * dev;
 };
 
@@ -324,6 +327,48 @@ QPacket QPacketProtocol::read()
     return rv;
 }
 
+/*
+   Returns the difference between msecs and elapsed. If msecs is -1,
+   however, -1 is returned.
+*/
+static int qt_timeout_value(int msecs, int elapsed)
+{
+    if (msecs == -1)
+        return -1;
+
+    int timeout = msecs - elapsed;
+    return timeout < 0 ? 0 : timeout;
+}
+
+/*!
+  This function locks until a new packet is available for reading and the
+  \l{QIODevice::}{readyRead()} signal has been emitted. The function
+  will timeout after \a msecs milliseconds; the default timeout is
+  30000 milliseconds.
+
+  The function returns true if the readyRead() signal is emitted and
+  there is new data available for reading; otherwise it returns false
+  (if an error occurred or the operation timed out).
+  */
+
+bool QPacketProtocol::waitForReadyRead(int msecs)
+{
+    if (!d->packets.isEmpty())
+        return true;
+
+    QElapsedTimer stopWatch;
+    stopWatch.start();
+
+    d->waitingForPacket = true;
+    do {
+        if (!d->dev->waitForReadyRead(msecs))
+            return false;
+        if (!d->waitingForPacket)
+            return true;
+        msecs = qt_timeout_value(msecs, stopWatch.elapsed());
+    } while (true);
+}
+
 /*!
   Return the QIODevice passed to the QPacketProtocol constructor.
 */
diff --git a/src/declarative/debugger/qpacketprotocol_p.h b/src/declarative/debugger/qpacketprotocol_p.h
index accb8ef..22bc3c2 100644
--- a/src/declarative/debugger/qpacketprotocol_p.h
+++ b/src/declarative/debugger/qpacketprotocol_p.h
@@ -75,6 +75,8 @@ public:
     qint64 packetsAvailable() const;
     QPacket read();
 
+    bool waitForReadyRead(int msecs = 3000);
+
     void clear();
 
     QIODevice * device();