V4 Debugger: Move all the jobs into one place

This makes the code more readable and allows us to keep the data
collector as value, rather than pointer, in QV4Debugger.

Change-Id: I2939c2b2f551111139f1dc34704a6029e87a66bf
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

8 files changed, 539 insertions, 437 deletions

diff --git a/src/plugins/qmltooling/qmldbg_debugger/qmldbg_debugger.pro b/src/plugins/qmltooling/qmldbg_debugger/qmldbg_debugger.pro
index 9db38d2dfe..3703d0fe0b 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qmldbg_debugger.pro
+++ b/src/plugins/qmltooling/qmldbg_debugger/qmldbg_debugger.pro
@@ -14,8 +14,8 @@ SOURCES += \
     $$PWD/qv4debugservice.cpp \
     $$PWD/qv4debugger.cpp \
     $$PWD/qv4debuggeragent.cpp \
-    $$PWD/qv4datacollector.cpp
-
+    $$PWD/qv4datacollector.cpp \
+    $$PWD/qv4debugjob.cpp
 
 HEADERS += \
     $$PWD/../shared/qqmlconfigurabledebugservice.h \
@@ -28,7 +28,8 @@ HEADERS += \
     $$PWD/qv4debugservice.h \
     $$PWD/qv4debugger.h \
     $$PWD/qv4debuggeragent.h \
-    $$PWD/qv4datacollector.h
+    $$PWD/qv4datacollector.h \
+    $$PWD/qv4debugjob.h
 
 INCLUDEPATH += $$PWD \
     $$PWD/../shared
diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.cpp b/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.cpp
index 78cb2be8d3..2d8a39e126 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.cpp
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.cpp
@@ -32,6 +32,8 @@
 ****************************************************************************/
 
 #include "qv4datacollector.h"
+#include "qv4debugger.h"
+#include "qv4debugjob.h"
 
 #include <private/qv4script_p.h>
 #include <private/qv4string_p.h>
@@ -353,206 +355,4 @@ QJsonObject QV4DataCollector::collectAsJson(const QString &name, const QV4::Scop
     return dict;
 }
 
-void ValueLookupJob::run()
-{
-    // Open a QML context if we don't have one, yet. We might run into QML objects when looking up
-    // refs and that will crash without a valid QML context. Mind that engine->qmlContext() is only
-    // set if the engine is currently executing QML code.
-    QScopedPointer<QObject> scopeObject;
-    QV4::ExecutionEngine *engine = collector->engine();
-    if (engine->qmlEngine() && !engine->qmlContext()) {
-        scopeObject.reset(new QObject);
-        engine->pushContext(engine->currentContext->newQmlContext(
-                                QQmlContextData::get(engine->qmlEngine()->rootContext()),
-                                scopeObject.data()));
-    }
-    foreach (const QJsonValue &handle, handles) {
-        QV4DataCollector::Ref ref = handle.toInt();
-        if (!collector->isValidRef(ref)) {
-            exception = QString::fromLatin1("Invalid Ref: %1").arg(ref);
-            break;
-        }
-        result[QString::number(ref)] = collector->lookupRef(ref);
-    }
-    collectedRefs = collector->flushCollectedRefs();
-    if (scopeObject)
-        engine->popContext();
-}
-
-const QString &ValueLookupJob::exceptionMessage() const
-{
-    return exception;
-}
-
-const QJsonObject &ValueLookupJob::returnValue() const
-{
-    return result;
-}
-
-const QJsonArray &ValueLookupJob::refs() const
-{
-    return collectedRefs;
-}
-
-ExpressionEvalJob::ExpressionEvalJob(QV4::ExecutionEngine *engine, int frameNr,
-                                     const QString &expression,
-                                     QV4DataCollector *collector)
-    : JavaScriptJob(engine, frameNr, expression)
-    , collector(collector)
-{
-}
-
-void ExpressionEvalJob::handleResult(QV4::ScopedValue &value)
-{
-    if (hasExeption())
-        exception = value->toQStringNoThrow();
-    result = collector->lookupRef(collector->collect(value));
-    collectedRefs = collector->flushCollectedRefs();
-}
-
-const QString &ExpressionEvalJob::exceptionMessage() const
-{
-    return exception;
-}
-
-const QJsonObject &ExpressionEvalJob::returnValue() const
-{
-    return result;
-}
-
-const QJsonArray &ExpressionEvalJob::refs() const
-{
-    return collectedRefs;
-}
-
-GatherSourcesJob::GatherSourcesJob(QV4::ExecutionEngine *engine)
-    : engine(engine)
-{}
-
-void GatherSourcesJob::run()
-{
-    foreach (QV4::CompiledData::CompilationUnit *unit, engine->compilationUnits) {
-        QString fileName = unit->fileName();
-        if (!fileName.isEmpty())
-            sources.append(fileName);
-    }
-}
-
-const QStringList &GatherSourcesJob::result() const
-{
-    return sources;
-}
-
-ArgumentCollectJob::ArgumentCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
-                                       QStringList *names, int frameNr, int scopeNr)
-    : engine(engine)
-    , collector(collector)
-    , names(names)
-    , frameNr(frameNr)
-    , scopeNr(scopeNr)
-{}
-
-void ArgumentCollectJob::run()
-{
-    if (frameNr < 0)
-        return;
-
-    QV4::Scope scope(engine);
-    QV4::Scoped<QV4::CallContext> ctxt(
-                scope, QV4DataCollector::findScope(QV4DataCollector::findContext(engine, frameNr), scopeNr));
-    if (!ctxt)
-        return;
-
-    QV4::ScopedValue v(scope);
-    int nFormals = ctxt->formalCount();
-    for (unsigned i = 0, ei = nFormals; i != ei; ++i) {
-        QString qName;
-        if (QV4::Identifier *name = ctxt->formals()[nFormals - i - 1])
-            qName = name->string;
-        names->append(qName);
-        v = ctxt->argument(i);
-        collector->collect(v);
-    }
-}
-
-LocalCollectJob::LocalCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
-                                 QStringList *names, int frameNr, int scopeNr)
-    : engine(engine)
-    , collector(collector)
-    , names(names)
-    , frameNr(frameNr)
-    , scopeNr(scopeNr)
-{}
-
-void LocalCollectJob::run()
-{
-    if (frameNr < 0)
-        return;
-
-    QV4::Scope scope(engine);
-    QV4::Scoped<QV4::CallContext> ctxt(
-                scope, QV4DataCollector::findScope(QV4DataCollector::findContext(engine, frameNr), scopeNr));
-    if (!ctxt)
-        return;
-
-    QV4::ScopedValue v(scope);
-    for (unsigned i = 0, ei = ctxt->variableCount(); i != ei; ++i) {
-        QString qName;
-        if (QV4::Identifier *name = ctxt->variables()[i])
-            qName = name->string;
-        names->append(qName);
-        v = ctxt->d()->locals[i];
-        collector->collect(v);
-    }
-}
-
-ThisCollectJob::ThisCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
-                               int frameNr)
-    : engine(engine)
-    , collector(collector)
-    , frameNr(frameNr)
-    , thisRef(QV4DataCollector::s_invalidRef)
-{}
-
-void ThisCollectJob::run()
-{
-    QV4::Scope scope(engine);
-    QV4::ScopedContext ctxt(scope, QV4DataCollector::findContext(engine, frameNr));
-    while (ctxt) {
-        if (QV4::CallContext *cCtxt = ctxt->asCallContext())
-            if (cCtxt->d()->activation)
-                break;
-        ctxt = ctxt->d()->outer;
-    }
-
-    if (!ctxt)
-        return;
-
-    QV4::ScopedValue o(scope, ctxt->asCallContext()->d()->activation);
-    thisRef = collector->collect(o);
-}
-
-QV4DataCollector::Ref ThisCollectJob::foundRef() const
-{
-    return thisRef;
-}
-
-ExceptionCollectJob::ExceptionCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector)
-    : engine(engine)
-    , collector(collector)
-    , exception(QV4DataCollector::s_invalidRef)
-{}
-
-void ExceptionCollectJob::run()
-{
-    QV4::Scope scope(engine);
-    QV4::ScopedValue v(scope, *engine->exceptionValue);
-    exception = collector->collect(v);
-}
-
-QV4DataCollector::Ref ExceptionCollectJob::exceptionValue() const
-{
-    return exception;
-}
-
 QT_END_NAMESPACE
diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.h b/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.h
index d1ff98f9b0..e57747fbc1 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.h
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.h
@@ -34,7 +34,6 @@
 #ifndef QV4DATACOLLECTOR_H
 #define QV4DATACOLLECTOR_H
 
-#include "qv4debugger.h"
 #include <private/qv4engine_p.h>
 #include <private/qv4persistent_p.h>
 
@@ -43,6 +42,7 @@
 
 QT_BEGIN_NAMESPACE
 
+class QV4Debugger;
 class QV4DataCollector
 {
 public:
@@ -86,103 +86,6 @@ private:
     SpecialRefs m_specialRefs;
 };
 
-class ValueLookupJob: public QV4Debugger::Job
-{
-    QV4DataCollector *collector;
-    const QJsonArray handles;
-    QJsonObject result;
-    QJsonArray collectedRefs;
-    QString exception;
-
-public:
-    ValueLookupJob(const QJsonArray &handles, QV4DataCollector *collector) :
-        collector(collector), handles(handles) {}
-    void run();
-    const QString &exceptionMessage() const;
-    const QJsonObject &returnValue() const;
-    const QJsonArray &refs() const;
-};
-
-class ExpressionEvalJob: public QV4Debugger::JavaScriptJob
-{
-    QV4DataCollector *collector;
-    QString exception;
-    QJsonObject result;
-    QJsonArray collectedRefs;
-
-public:
-    ExpressionEvalJob(QV4::ExecutionEngine *engine, int frameNr, const QString &expression,
-                      QV4DataCollector *collector);
-    virtual void handleResult(QV4::ScopedValue &value);
-    const QString &exceptionMessage() const;
-    const QJsonObject &returnValue() const;
-    const QJsonArray &refs() const;
-};
-
-class GatherSourcesJob: public QV4Debugger::Job
-{
-    QV4::ExecutionEngine *engine;
-    QStringList sources;
-
-public:
-    GatherSourcesJob(QV4::ExecutionEngine *engine);
-    void run();
-    const QStringList &result() const;
-};
-
-class ArgumentCollectJob: public QV4Debugger::Job
-{
-    QV4::ExecutionEngine *engine;
-    QV4DataCollector *collector;
-    QStringList *names;
-    int frameNr;
-    int scopeNr;
-
-public:
-    ArgumentCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
-                       QStringList *names, int frameNr, int scopeNr);
-    void run();
-};
-
-class LocalCollectJob: public QV4Debugger::Job
-{
-    QV4::ExecutionEngine *engine;
-    QV4DataCollector *collector;
-    QStringList *names;
-    int frameNr;
-    int scopeNr;
-
-public:
-    LocalCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector, QStringList *names,
-                    int frameNr, int scopeNr);
-    void run();
-};
-
-class ThisCollectJob: public QV4Debugger::Job
-{
-    QV4::ExecutionEngine *engine;
-    QV4DataCollector *collector;
-    int frameNr;
-    QV4DataCollector::Ref thisRef;
-
-public:
-    ThisCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector, int frameNr);
-    void run();
-    QV4DataCollector::Ref foundRef() const;
-};
-
-class ExceptionCollectJob: public QV4Debugger::Job
-{
-    QV4::ExecutionEngine *engine;
-    QV4DataCollector *collector;
-    QV4DataCollector::Ref exception;
-
-public:
-    ExceptionCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector);
-    void run();
-    QV4DataCollector::Ref exceptionValue() const;
-};
-
 QT_END_NAMESPACE
 
 #endif // QV4DATACOLLECTOR_H
diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4debugger.cpp b/src/plugins/qmltooling/qmldbg_debugger/qv4debugger.cpp
index b7c310edd8..6ff3b81b4b 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qv4debugger.cpp
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4debugger.cpp
@@ -32,6 +32,7 @@
 ****************************************************************************/
 
 #include "qv4debugger.h"
+#include "qv4debugjob.h"
 #include "qv4datacollector.h"
 
 #include <private/qv4scopedvalue_p.h>
@@ -56,97 +57,6 @@ inline bool operator==(const QV4Debugger::BreakPoint &a,
     return a.lineNumber == b.lineNumber && a.fileName == b.fileName;
 }
 
-QV4Debugger::JavaScriptJob::JavaScriptJob(QV4::ExecutionEngine *engine, int frameNr,
-                                         const QString &script)
-    : engine(engine)
-    , frameNr(frameNr)
-    , script(script)
-    , resultIsException(false)
-{}
-
-void QV4Debugger::JavaScriptJob::run()
-{
-    QV4::Scope scope(engine);
-
-    QV4::ExecutionContextSaver saver(scope);
-
-    QV4::ExecutionContext *ctx = engine->currentContext;
-    QObject scopeObject;
-    if (frameNr < 0) { // Use QML context if available
-        QQmlEngine *qmlEngine = engine->qmlEngine();
-        if (qmlEngine) {
-            QQmlContext *qmlRootContext = qmlEngine->rootContext();
-            QQmlContextPrivate *ctxtPriv = QQmlContextPrivate::get(qmlRootContext);
-
-            QV4::ScopedObject withContext(scope, engine->newObject());
-            for (int ii = 0; ii < ctxtPriv->instances.count(); ++ii) {
-                QObject *object = ctxtPriv->instances.at(ii);
-                if (QQmlContext *context = qmlContext(object)) {
-                    if (QQmlContextData *cdata = QQmlContextData::get(context)) {
-                        QV4::ScopedValue v(scope, QV4::QObjectWrapper::wrap(engine, object));
-                        withContext->put(engine, cdata->findObjectId(object), v);
-                    }
-                }
-            }
-            if (!engine->qmlContext()) {
-                engine->pushContext(ctx->newQmlContext(QQmlContextData::get(qmlRootContext),
-                                                       &scopeObject));
-                ctx = engine->currentContext;
-            }
-            engine->pushContext(ctx->newWithContext(withContext->toObject(engine)));
-            ctx = engine->currentContext;
-        }
-    } else {
-        if (frameNr > 0) {
-            for (int i = 0; i < frameNr; ++i) {
-                ctx = engine->parentContext(ctx);
-            }
-            engine->pushContext(ctx);
-        }
-    }
-
-    QV4::Script script(ctx, this->script);
-    script.strictMode = ctx->d()->strictMode;
-    // In order for property lookups in QML to work, we need to disable fast v4 lookups. That
-    // is a side-effect of inheritContext.
-    script.inheritContext = true;
-    script.parse();
-    QV4::ScopedValue result(scope);
-    if (!scope.engine->hasException)
-        result = script.run();
-    if (scope.engine->hasException) {
-        result = scope.engine->catchException();
-        resultIsException = true;
-    }
-    handleResult(result);
-}
-
-bool QV4Debugger::JavaScriptJob::hasExeption() const
-{
-    return resultIsException;
-}
-
-class EvalJob: public QV4Debugger::JavaScriptJob
-{
-    bool result;
-
-public:
-    EvalJob(QV4::ExecutionEngine *engine, const QString &script)
-        : QV4Debugger::JavaScriptJob(engine, /*frameNr*/-1, script)
-        , result(false)
-    {}
-
-    virtual void handleResult(QV4::ScopedValue &result)
-    {
-        this->result = result->toBoolean();
-    }
-
-    bool resultAsBoolean() const
-    {
-        return result;
-    }
-};
-
 QV4Debugger::QV4Debugger(QV4::ExecutionEngine *engine)
     : m_engine(engine)
     , m_state(Running)
@@ -157,7 +67,7 @@ QV4Debugger::QV4Debugger(QV4::ExecutionEngine *engine)
     , m_returnedValue(engine, QV4::Primitive::undefinedValue())
     , m_gatherSources(0)
     , m_runningJob(0)
-    , m_collector(new QV4DataCollector(engine))
+    , m_collector(engine)
 {
     static int debuggerId = qRegisterMetaType<QV4Debugger*>();
     static int pauseReasonId = qRegisterMetaType<QV4Debugger::PauseReason>();
@@ -165,19 +75,19 @@ QV4Debugger::QV4Debugger(QV4::ExecutionEngine *engine)
     Q_UNUSED(pauseReasonId);
 }
 
-QV4Debugger::~QV4Debugger()
+QV4::ExecutionEngine *QV4Debugger::engine() const
 {
-    delete m_collector;
+    return m_engine;
 }
 
-QV4::ExecutionEngine *QV4Debugger::engine() const
+const QV4DataCollector *QV4Debugger::collector() const
 {
-    return m_engine;
+    return &m_collector;
 }
 
-QV4DataCollector *QV4Debugger::collector() const
+QV4DataCollector *QV4Debugger::collector()
 {
-    return m_collector;
+    return &m_collector;
 }
 
 void QV4Debugger::pause()
@@ -389,13 +299,13 @@ bool QV4Debugger::reallyHitTheBreakPoint(const QString &filename, int linenr)
     return evilJob.resultAsBoolean();
 }
 
-void QV4Debugger::runInEngine(QV4Debugger::Job *job)
+void QV4Debugger::runInEngine(QV4DebugJob *job)
 {
     QMutexLocker locker(&m_lock);
     runInEngine_havingLock(job);
 }
 
-void QV4Debugger::runInEngine_havingLock(QV4Debugger::Job *job)
+void QV4Debugger::runInEngine_havingLock(QV4DebugJob *job)
 {
     Q_ASSERT(job);
     Q_ASSERT(m_runningJob == 0);
@@ -409,8 +319,4 @@ void QV4Debugger::runInEngine_havingLock(QV4Debugger::Job *job)
     m_runningJob = 0;
 }
 
-QV4Debugger::Job::~Job()
-{
-}
-
 QT_END_NAMESPACE
diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4debugger.h b/src/plugins/qmltooling/qmldbg_debugger/qv4debugger.h
index abb43f82f3..98224d5075 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qv4debugger.h
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4debugger.h
@@ -45,6 +45,7 @@
 // We mean it.
 //
 
+#include "qv4datacollector.h"
 #include <private/qv4debugging_p.h>
 #include <private/qv4function_p.h>
 #include <private/qv4context_p.h>
@@ -55,6 +56,7 @@
 
 QT_BEGIN_NAMESPACE
 
+class QV4DebugJob;
 class QV4DataCollector;
 class QV4Debugger : public QV4::Debugging::Debugger
 {
@@ -66,29 +68,6 @@ public:
         int lineNumber;
     };
 
-    class Job
-    {
-    public:
-        virtual ~Job();
-        virtual void run() = 0;
-    };
-
-    class JavaScriptJob: public Job
-    {
-        QV4::ExecutionEngine *engine;
-        int frameNr;
-        const QString &script;
-        bool resultIsException;
-
-    public:
-        JavaScriptJob(QV4::ExecutionEngine *engine, int frameNr, const QString &script);
-        void run();
-        bool hasExeption() const;
-
-    protected:
-        virtual void handleResult(QV4::ScopedValue &result) = 0;
-    };
-
     enum State {
         Running,
         Paused
@@ -111,10 +90,10 @@ public:
     };
 
     QV4Debugger(QV4::ExecutionEngine *engine);
-    ~QV4Debugger();
 
     QV4::ExecutionEngine *engine() const;
-    QV4DataCollector *collector() const;
+    const QV4DataCollector *collector() const;
+    QV4DataCollector *collector();
 
     void pause();
     void resume(Speed speed);
@@ -141,7 +120,7 @@ public:
     QVector<QV4::Heap::ExecutionContext::ContextType> getScopeTypes(int frame = 0) const;
 
     QV4::Function *getFunction() const;
-    void runInEngine(Job *job);
+    void runInEngine(QV4DebugJob *job);
 
     // compile-time interface
     void maybeBreakAtInstruction() Q_DECL_OVERRIDE;
@@ -163,7 +142,7 @@ private:
     // requires lock to be held
     void pauseAndWait(PauseReason reason);
     bool reallyHitTheBreakPoint(const QString &filename, int linenr);
-    void runInEngine_havingLock(QV4Debugger::Job *job);
+    void runInEngine_havingLock(QV4DebugJob *job);
 
     QV4::ExecutionEngine *m_engine;
     QV4::PersistentValue m_currentContext;
@@ -178,9 +157,9 @@ private:
     QHash<BreakPoint, QString> m_breakPoints;
     QV4::PersistentValue m_returnedValue;
 
-    Job *m_gatherSources;
-    Job *m_runningJob;
-    QV4DataCollector *m_collector;
+    QV4DebugJob *m_gatherSources;
+    QV4DebugJob *m_runningJob;
+    QV4DataCollector m_collector;
     QWaitCondition m_jobIsRunning;
 };
 
diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp b/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp
new file mode 100644
index 0000000000..572ea805a5
--- /dev/null
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp
@@ -0,0 +1,332 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** 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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qv4debugjob.h"
+
+#include <private/qv4script_p.h>
+#include <private/qqmlcontext_p.h>
+#include <private/qv4qobjectwrapper_p.h>
+
+#include <QtQml/qqmlengine.h>
+
+QT_BEGIN_NAMESPACE
+
+QV4DebugJob::~QV4DebugJob()
+{
+}
+
+JavaScriptJob::JavaScriptJob(QV4::ExecutionEngine *engine, int frameNr,
+                                   const QString &script) :
+    engine(engine), frameNr(frameNr), script(script), resultIsException(false)
+{}
+
+void JavaScriptJob::run()
+{
+    QV4::Scope scope(engine);
+
+    QV4::ExecutionContextSaver saver(scope);
+
+    QV4::ExecutionContext *ctx = engine->currentContext;
+    QObject scopeObject;
+    if (frameNr < 0) { // Use QML context if available
+        QQmlEngine *qmlEngine = engine->qmlEngine();
+        if (qmlEngine) {
+            QQmlContext *qmlRootContext = qmlEngine->rootContext();
+            QQmlContextPrivate *ctxtPriv = QQmlContextPrivate::get(qmlRootContext);
+
+            QV4::ScopedObject withContext(scope, engine->newObject());
+            for (int ii = 0; ii < ctxtPriv->instances.count(); ++ii) {
+                QObject *object = ctxtPriv->instances.at(ii);
+                if (QQmlContext *context = qmlContext(object)) {
+                    if (QQmlContextData *cdata = QQmlContextData::get(context)) {
+                        QV4::ScopedValue v(scope, QV4::QObjectWrapper::wrap(engine, object));
+                        withContext->put(engine, cdata->findObjectId(object), v);
+                    }
+                }
+            }
+            if (!engine->qmlContext()) {
+                engine->pushContext(ctx->newQmlContext(QQmlContextData::get(qmlRootContext),
+                                                       &scopeObject));
+                ctx = engine->currentContext;
+            }
+            engine->pushContext(ctx->newWithContext(withContext->toObject(engine)));
+            ctx = engine->currentContext;
+        }
+    } else {
+        if (frameNr > 0) {
+            for (int i = 0; i < frameNr; ++i) {
+                ctx = engine->parentContext(ctx);
+            }
+            engine->pushContext(ctx);
+        }
+    }
+
+    QV4::Script script(ctx, this->script);
+    script.strictMode = ctx->d()->strictMode;
+    // In order for property lookups in QML to work, we need to disable fast v4 lookups. That
+    // is a side-effect of inheritContext.
+    script.inheritContext = true;
+    script.parse();
+    QV4::ScopedValue result(scope);
+    if (!scope.engine->hasException)
+        result = script.run();
+    if (scope.engine->hasException) {
+        result = scope.engine->catchException();
+        resultIsException = true;
+    }
+    handleResult(result);
+}
+
+bool JavaScriptJob::hasExeption() const
+{
+    return resultIsException;
+}
+
+ValueLookupJob::ValueLookupJob(const QJsonArray &handles, QV4DataCollector *collector) :
+    collector(collector), handles(handles) {}
+
+void ValueLookupJob::run()
+{
+    // Open a QML context if we don't have one, yet. We might run into QML objects when looking up
+    // refs and that will crash without a valid QML context. Mind that engine->qmlContext() is only
+    // set if the engine is currently executing QML code.
+    QScopedPointer<QObject> scopeObject;
+    QV4::ExecutionEngine *engine = collector->engine();
+    if (engine->qmlEngine() && !engine->qmlContext()) {
+        scopeObject.reset(new QObject);
+        engine->pushContext(engine->currentContext->newQmlContext(
+                                QQmlContextData::get(engine->qmlEngine()->rootContext()),
+                                scopeObject.data()));
+    }
+    foreach (const QJsonValue &handle, handles) {
+        QV4DataCollector::Ref ref = handle.toInt();
+        if (!collector->isValidRef(ref)) {
+            exception = QString::fromLatin1("Invalid Ref: %1").arg(ref);
+            break;
+        }
+        result[QString::number(ref)] = collector->lookupRef(ref);
+    }
+    collectedRefs = collector->flushCollectedRefs();
+    if (scopeObject)
+        engine->popContext();
+}
+
+const QString &ValueLookupJob::exceptionMessage() const
+{
+    return exception;
+}
+
+const QJsonObject &ValueLookupJob::returnValue() const
+{
+    return result;
+}
+
+const QJsonArray &ValueLookupJob::refs() const
+{
+    return collectedRefs;
+}
+
+ExpressionEvalJob::ExpressionEvalJob(QV4::ExecutionEngine *engine, int frameNr,
+                                     const QString &expression, QV4DataCollector *collector) :
+    JavaScriptJob(engine, frameNr, expression), collector(collector)
+{
+}
+
+void ExpressionEvalJob::handleResult(QV4::ScopedValue &value)
+{
+    if (hasExeption())
+        exception = value->toQStringNoThrow();
+    result = collector->lookupRef(collector->collect(value));
+    collectedRefs = collector->flushCollectedRefs();
+}
+
+const QString &ExpressionEvalJob::exceptionMessage() const
+{
+    return exception;
+}
+
+const QJsonObject &ExpressionEvalJob::returnValue() const
+{
+    return result;
+}
+
+const QJsonArray &ExpressionEvalJob::refs() const
+{
+    return collectedRefs;
+}
+
+GatherSourcesJob::GatherSourcesJob(QV4::ExecutionEngine *engine)
+    : engine(engine)
+{}
+
+void GatherSourcesJob::run()
+{
+    foreach (QV4::CompiledData::CompilationUnit *unit, engine->compilationUnits) {
+        QString fileName = unit->fileName();
+        if (!fileName.isEmpty())
+            sources.append(fileName);
+    }
+}
+
+const QStringList &GatherSourcesJob::result() const
+{
+    return sources;
+}
+
+ArgumentCollectJob::ArgumentCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
+                                       QStringList *names, int frameNr, int scopeNr)
+    : engine(engine)
+    , collector(collector)
+    , names(names)
+    , frameNr(frameNr)
+    , scopeNr(scopeNr)
+{}
+
+void ArgumentCollectJob::run()
+{
+    if (frameNr < 0)
+        return;
+
+    QV4::Scope scope(engine);
+    QV4::Scoped<QV4::CallContext> ctxt(
+                scope, QV4DataCollector::findScope(QV4DataCollector::findContext(engine, frameNr), scopeNr));
+    if (!ctxt)
+        return;
+
+    QV4::ScopedValue v(scope);
+    int nFormals = ctxt->formalCount();
+    for (unsigned i = 0, ei = nFormals; i != ei; ++i) {
+        QString qName;
+        if (QV4::Identifier *name = ctxt->formals()[nFormals - i - 1])
+            qName = name->string;
+        names->append(qName);
+        v = ctxt->argument(i);
+        collector->collect(v);
+    }
+}
+
+LocalCollectJob::LocalCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
+                                 QStringList *names, int frameNr, int scopeNr)
+    : engine(engine)
+    , collector(collector)
+    , names(names)
+    , frameNr(frameNr)
+    , scopeNr(scopeNr)
+{}
+
+void LocalCollectJob::run()
+{
+    if (frameNr < 0)
+        return;
+
+    QV4::Scope scope(engine);
+    QV4::Scoped<QV4::CallContext> ctxt(
+                scope, QV4DataCollector::findScope(QV4DataCollector::findContext(engine, frameNr), scopeNr));
+    if (!ctxt)
+        return;
+
+    QV4::ScopedValue v(scope);
+    for (unsigned i = 0, ei = ctxt->variableCount(); i != ei; ++i) {
+        QString qName;
+        if (QV4::Identifier *name = ctxt->variables()[i])
+            qName = name->string;
+        names->append(qName);
+        v = ctxt->d()->locals[i];
+        collector->collect(v);
+    }
+}
+
+ThisCollectJob::ThisCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
+                               int frameNr)
+    : engine(engine)
+    , collector(collector)
+    , frameNr(frameNr)
+    , thisRef(QV4DataCollector::s_invalidRef)
+{}
+
+void ThisCollectJob::run()
+{
+    QV4::Scope scope(engine);
+    QV4::ScopedContext ctxt(scope, QV4DataCollector::findContext(engine, frameNr));
+    while (ctxt) {
+        if (QV4::CallContext *cCtxt = ctxt->asCallContext())
+            if (cCtxt->d()->activation)
+                break;
+        ctxt = ctxt->d()->outer;
+    }
+
+    if (!ctxt)
+        return;
+
+    QV4::ScopedValue o(scope, ctxt->asCallContext()->d()->activation);
+    thisRef = collector->collect(o);
+}
+
+QV4DataCollector::Ref ThisCollectJob::foundRef() const
+{
+    return thisRef;
+}
+
+ExceptionCollectJob::ExceptionCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector)
+    : engine(engine)
+    , collector(collector)
+    , exception(QV4DataCollector::s_invalidRef)
+{}
+
+void ExceptionCollectJob::run()
+{
+    QV4::Scope scope(engine);
+    QV4::ScopedValue v(scope, *engine->exceptionValue);
+    exception = collector->collect(v);
+}
+
+QV4DataCollector::Ref ExceptionCollectJob::exceptionValue() const
+{
+    return exception;
+}
+
+EvalJob::EvalJob(QV4::ExecutionEngine *engine, const QString &script) :
+    JavaScriptJob(engine, /*frameNr*/-1, script), result(false)
+{}
+
+void EvalJob::handleResult(QV4::ScopedValue &result)
+{
+    this->result = result->toBoolean();
+}
+
+bool EvalJob::resultAsBoolean() const
+{
+    return result;
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.h b/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.h
new file mode 100644
index 0000000000..b758868ace
--- /dev/null
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.h
@@ -0,0 +1,180 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** 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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** As a special exception, The Qt Company gives you certain additional
+** rights. These rights are described in The Qt Company LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QV4DEBUGJOB_H
+#define QV4DEBUGJOB_H
+
+#include "qv4datacollector.h"
+#include <private/qv4engine_p.h>
+
+#include <QtCore/qjsonarray.h>
+#include <QtCore/qjsonobject.h>
+
+QT_BEGIN_NAMESPACE
+
+class QV4DataCollector;
+class QV4DebugJob
+{
+public:
+    virtual ~QV4DebugJob();
+    virtual void run() = 0;
+};
+
+class JavaScriptJob : public QV4DebugJob
+{
+    QV4::ExecutionEngine *engine;
+    int frameNr;
+    const QString &script;
+    bool resultIsException;
+
+public:
+    JavaScriptJob(QV4::ExecutionEngine *engine, int frameNr, const QString &script);
+    void run();
+    bool hasExeption() const;
+
+protected:
+    virtual void handleResult(QV4::ScopedValue &result) = 0;
+};
+
+class ValueLookupJob: public QV4DebugJob
+{
+    QV4DataCollector *collector;
+    const QJsonArray handles;
+    QJsonObject result;
+    QJsonArray collectedRefs;
+    QString exception;
+
+public:
+    ValueLookupJob(const QJsonArray &handles, QV4DataCollector *collector);
+    void run();
+    const QString &exceptionMessage() const;
+    const QJsonObject &returnValue() const;
+    const QJsonArray &refs() const;
+};
+
+class ExpressionEvalJob: public JavaScriptJob
+{
+    QV4DataCollector *collector;
+    QString exception;
+    QJsonObject result;
+    QJsonArray collectedRefs;
+
+public:
+    ExpressionEvalJob(QV4::ExecutionEngine *engine, int frameNr, const QString &expression,
+                      QV4DataCollector *collector);
+    virtual void handleResult(QV4::ScopedValue &value);
+    const QString &exceptionMessage() const;
+    const QJsonObject &returnValue() const;
+    const QJsonArray &refs() const;
+};
+
+class GatherSourcesJob: public QV4DebugJob
+{
+    QV4::ExecutionEngine *engine;
+    QStringList sources;
+
+public:
+    GatherSourcesJob(QV4::ExecutionEngine *engine);
+    void run();
+    const QStringList &result() const;
+};
+
+class ArgumentCollectJob: public QV4DebugJob
+{
+    QV4::ExecutionEngine *engine;
+    QV4DataCollector *collector;
+    QStringList *names;
+    int frameNr;
+    int scopeNr;
+
+public:
+    ArgumentCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector,
+                       QStringList *names, int frameNr, int scopeNr);
+    void run();
+};
+
+class LocalCollectJob: public QV4DebugJob
+{
+    QV4::ExecutionEngine *engine;
+    QV4DataCollector *collector;
+    QStringList *names;
+    int frameNr;
+    int scopeNr;
+
+public:
+    LocalCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector, QStringList *names,
+                    int frameNr, int scopeNr);
+    void run();
+};
+
+class ThisCollectJob: public QV4DebugJob
+{
+    QV4::ExecutionEngine *engine;
+    QV4DataCollector *collector;
+    int frameNr;
+    QV4DataCollector::Ref thisRef;
+
+public:
+    ThisCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector, int frameNr);
+    void run();
+    QV4DataCollector::Ref foundRef() const;
+};
+
+class ExceptionCollectJob: public QV4DebugJob
+{
+    QV4::ExecutionEngine *engine;
+    QV4DataCollector *collector;
+    QV4DataCollector::Ref exception;
+
+public:
+    ExceptionCollectJob(QV4::ExecutionEngine *engine, QV4DataCollector *collector);
+    void run();
+    QV4DataCollector::Ref exceptionValue() const;
+};
+
+class EvalJob: public JavaScriptJob
+{
+    bool result;
+
+public:
+    EvalJob(QV4::ExecutionEngine *engine, const QString &script);
+
+    virtual void handleResult(QV4::ScopedValue &result);
+    bool resultAsBoolean() const
+;
+};
+
+QT_END_NAMESPACE
+
+#endif // QV4DEBUGJOB_H
+
diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4debugservice.cpp b/src/plugins/qmltooling/qmldbg_debugger/qv4debugservice.cpp
index dcf1fe8335..1c1e9e48df 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qv4debugservice.cpp
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4debugservice.cpp
@@ -32,6 +32,7 @@
 ****************************************************************************/
 
 #include "qv4debugservice.h"
+#include "qv4debugjob.h"
 #include "qqmlengine.h"
 #include "qqmldebugpacket.h"