[transfer-engine] Prevent premature exits

If TransferEnginePrivate::exitSafely() finds out that activity is still
ongoing it should cancel previously sheduled delayedExitSafely() call.
Otherwise delayedExitSafely() may be invoked between two syncs causing
nemo-transfer-engine to exit and get immediately restarted by D-Bus which
isn't something we really want. We want to exit when all the activity has
really calmed down.

src/transferengine.cpp

@@ -147,6 +147,11 @@ TransferEnginePrivate::TransferEnginePrivate(TransferEngine *parent):
     m_fileWatcherTimer->setSingleShot(true);
     connect(m_fileWatcherTimer, SIGNAL(timeout()), this, SLOT(enabledPluginsCheck()));
 
+    m_delayedExitTimer = new QTimer(this);
+    m_delayedExitTimer->setSingleShot(true);
+    m_delayedExitTimer->setInterval(5000);
+    connect(m_delayedExitTimer, SIGNAL(timeout()), this, SLOT(delayedExitSafely()));
+
     m_fileWatcher = new QFileSystemWatcher(this);
     m_fileWatcher->addPath(SHARE_PLUGINS_PATH);
     connect(m_fileWatcher, SIGNAL(directoryChanged(QString)), this, SLOT(pluginDirChanged()));
@@ -177,19 +182,17 @@ void TransferEnginePrivate::pluginDirChanged()
 void TransferEnginePrivate::exitSafely()
 {
     if (!m_activityMonitor->activeTransfers()) {
-        qDebug() << Q_FUNC_INFO;
-        QTimer::singleShot(2000, this, SLOT(delayedExitSafely()));
+        qDebug() << "Scheduling exit in" << m_delayedExitTimer->interval() << "ms";
+        m_delayedExitTimer->start();
+    } else {
+        m_delayedExitTimer->stop();
     }
 }
 
 void TransferEnginePrivate::delayedExitSafely()
 {
-    if (m_activityMonitor->activeTransfers()) {
-        qDebug() << "Keeping transfer engine alive, transfers still ongoing";
-    } else {
-        qDebug() << "Stopping transfer engine";
-        qApp->exit();
-    }
+    qDebug() << "Stopping transfer engine";
+    qApp->exit();
 }
 
 void TransferEnginePrivate::enabledPluginsCheck()

src/transferengine_p.h

@@ -83,8 +83,6 @@ public Q_SLOTS:
     QTimer *m_timer;
 };
 
-
-
 class TransferEnginePrivate: QObject
 {
     Q_OBJECT
@@ -133,6 +131,7 @@ public Q_SLOTS:
     MediaTransferInterface *loadPlugin(const QString &pluginId) const;
     QString mediaFileOrResourceName(MediaItem *mediaItem) const;
 
+private:
     QMap <MediaTransferInterface*, int> m_plugins;
     QMap <int, TransferEngineData::TransferType> m_keyTypeCache;
     bool m_notificationsEnabled;
@@ -141,6 +140,7 @@ public Q_SLOTS:
     Accounts::Manager *m_accountManager;
     QFileSystemWatcher *m_fileWatcher;
     QTimer *m_fileWatcherTimer;
+    QTimer *m_delayedExitTimer;
     QSettings m_settings;
     ClientActivityMonitor *m_activityMonitor;
     TransferEngine *q_ptr;