Initialize gstreamer independent of witch engine is used

src/engine/gststartup.h

@@ -0,0 +1,47 @@
+/*
+ * Strawberry Music Player
+ * Copyright 2018, Jonas Kvinge <jonas@jkvinge.net>
+ *
+ * Strawberry is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Strawberry is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef GSTSTARTUP_H
+#define GSTSTARTUP_H
+
+#include "config.h"
+
+#include <gst/gst.h>
+
+#include <QtGlobal>
+#include <QObject>
+#include <QFuture>
+
+class GstStartup : public QObject {
+  Q_OBJECT
+
+ public:
+  explicit GstStartup(QObject *parent = nullptr);
+  ~GstStartup();
+
+  void EnsureInitialised() { initialising_.waitForFinished(); }
+
+ private:
+  void InitialiseGStreamer();
+  void SetEnvironment();
+  QFuture<void> initialising_;
+
+};
+
+#endif  /* GSTSTARTUP_H */