Let xbus retry to connect to dbus in case it is not available

refs #615

src/xbus/plugin.cpp

@@ -13,6 +13,9 @@
 #include "weather.h"
 #include "utils.h"
 #include "blackmisc/librarypath.h"
+#include "blackmisc/logmessage.h"
+#include <QTimer>
+#include <functional>
 
 namespace {
     inline QString xbusServiceName() {
@@ -33,21 +36,39 @@ namespace XBus
 
     void CPlugin::startServer(const QString &address)
     {
-        Q_ASSERT(! m_server);
         for (auto &item : m_startServerMenuItems) { item.setEnabled(false); }
 
+        m_service = new CService(this);
+        m_traffic = new CTraffic(this);
+        m_weather = new CWeather(this);
+
+        // XPLM API does not like to be called from a QTimer slot, so move the recurring part into a separate method.
+        tryStartServer(address);
+    }
+
+    void CPlugin::tryStartServer(const QString &address)
+    {
+        // Make sure that there are no calls to XPLM in this method
+        Q_ASSERT(! m_server);
         auto previousLibraryPath = BlackMisc::getCustomLibraryPath();
         auto libraryPath = g_xplanePath + "Resources" + g_sep + "plugins" + g_sep + "xbus";
         #if !defined (Q_OS_MAC) && defined(WORD_SIZE_64)
         libraryPath = libraryPath + g_sep + "64";
         #endif
         BlackMisc::setCustomLibraryPath(libraryPath);
+
+        if (!BlackMisc::CDBusServer::isP2PAddress(address) && !BlackMisc::CDBusServer::isDBusAvailable(address))
+        {
+            constexpr int msec = 30000;
+            BlackMisc::CLogMessage(this).warning("DBus daemon not available. Trying again in %1 sec.") << msec / 1000;
+            QTimer::singleShot(msec, this, [&] { tryStartServer(address); });
+            BlackMisc::setCustomLibraryPath(previousLibraryPath);
+            return;
+        }
+
         m_server = new BlackMisc::CDBusServer(xbusServiceName(), address, this);
         BlackMisc::setCustomLibraryPath(previousLibraryPath);
 
-        m_service = new CService(this);
-        m_traffic = new CTraffic(this);
-        m_weather = new CWeather(this);
         m_server->addObject(CService::ObjectPath(), m_service);
         m_server->addObject(CTraffic::ObjectPath(), m_traffic);
         m_server->addObject(CWeather::ObjectPath(), m_weather);

src/xbus/plugin.h

@@ -61,6 +61,7 @@ namespace XBus
         QVector<CMenuItem> m_startServerMenuItems;
 
         void startServer(const QString &address);
+        void tryStartServer(const QString &address);
     };
 }