QML Preview: Add a frames per second counter

It is instructive to the client to know how many frames per second the
current QML can achieve in the preview.

Change-Id: I8b73e2b5218410d903a07dfe27c038663c84fdee
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 22 insertions, 9 deletions

diff --git a/src/qmldebug/qqmlpreviewclient.cpp b/src/qmldebug/qqmlpreviewclient.cpp
index fa040e226b..33a2f53ca4 100644
--- a/src/qmldebug/qqmlpreviewclient.cpp
+++ b/src/qmldebug/qqmlpreviewclient.cpp
@@ -61,18 +61,29 @@ void QQmlPreviewClient::messageReceived(const QByteArray &message)
     qint8 command;
     packet >> command;
 
-    if (command == Error) {
+    switch (command) {
+    case Error: {
         QString seviceError;
         packet >> seviceError;
         emit error(seviceError);
-        return;
+        break;
+    }
+    case Request: {
+        QString fileName;
+        packet >> fileName;
+        emit request(fileName);
+        break;
+    }
+    case Fps: {
+        quint16 frames;
+        packet >> frames;
+        emit fps(frames);
+        break;
+    }
+    default:
+        emit error(QString::fromLatin1("Unknown command received: %1").arg(command));
+        break;
     }
-
-    Q_ASSERT(command == Request);
-
-    QString fileName;
-    packet >> fileName;
-    emit request(fileName);
 }
 
 void QQmlPreviewClient::sendDirectory(const QString &path, const QStringList &entries)
diff --git a/src/qmldebug/qqmlpreviewclient_p.h b/src/qmldebug/qqmlpreviewclient_p.h
index 49d147c866..d79ecefe32 100644
--- a/src/qmldebug/qqmlpreviewclient_p.h
+++ b/src/qmldebug/qqmlpreviewclient_p.h
@@ -71,7 +71,8 @@ public:
         Rerun,
         Directory,
         ClearCache,
-        Zoom
+        Zoom,
+        Fps
     };
 
     QQmlPreviewClient(QQmlDebugConnection *parent);
@@ -88,6 +89,7 @@ public:
 signals:
     void request(const QString &path);
     void error(const QString &message);
+    void fps(quint16 frames);
 };
 
 QT_END_NAMESPACE