QmlProfiler: Detect interrupted execution

Task-number: QTCREATORBUG-8022

The profiler would switch to state "AppKilled" if the connection was
cut before all the profiling data could be read.  With Qt4.8, however,
the application dies before any data is sent at all, and such state
would never be reached.  This patch fixes the flow of states and
properly detects when an application started profiling successfully
but dies before delivering the data.  If the application doesn't run
at all (for example, launching a QtQuick1.1 app from Qt5), the
profiler fails gracefully without showing the error dialog.

Change-Id: I6fc53127b5dfe41de112e140b77895d430d3f79c
Reviewed-by: Kai Koehne <kai.koehne@digia.com>

src/plugins/qmlprofiler/qmlprofilerdatamodel.cpp

@@ -290,6 +290,11 @@ void QmlProfilerDataModel::clear()
     setState(Empty);
 }
 
+void QmlProfilerDataModel::prepareForWriting()
+{
+    setState(AcquiringData);
+}
+
 void QmlProfilerDataModel::addRangedEvent(int type, int bindingType, qint64 startTime,
                                           qint64 length, const QStringList &data,
                                           const QmlDebug::QmlEventLocation &location)

src/plugins/qmlprofiler/qmlprofilerdatamodel.h

@@ -165,6 +165,7 @@ signals:
 public slots:
     void clear();
 
+    void prepareForWriting();
     void addRangedEvent(int type, int bindingType, qint64 startTime, qint64 length,
                         const QStringList &data, const QmlDebug::QmlEventLocation &location);
     void addV8Event(int depth,const QString &function,const QString &filename, int lineNumber, double totalTime, double selfTime);

src/plugins/qmlprofiler/qmlprofilertool.cpp

@@ -692,6 +692,7 @@ void QmlProfilerTool::profilerStateChanged()
     }
     case QmlProfilerStateManager::AppKilled : {
         showNonmodalWarning(tr("Application finished before loading profiled data.\nPlease use the stop button instead."));
+        d->m_profilerDataModel->clear();
         break;
     }
     case QmlProfilerStateManager::Idle :
@@ -720,6 +721,7 @@ void QmlProfilerTool::serverRecordingChanged()
         // clear the old data each time we start a new profiling session
         if (d->m_profilerState->serverRecording()) {
             clearData();
+            d->m_profilerDataModel->prepareForWriting();
         }
     }
 }