From f1211d328ec3646d2ed51c6208eb5b812887287c Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Fri, 8 Sep 2017 17:49:00 +0100
Subject: [PATCH] Delete QDBusServiceWatcher when unloading X-Plane driver.

Summary:
When unloading a sim driver, first its threads are killed, then the driver object is destroyed.

This means that when the `QDBusServiceWatcher` child object is destroyed, it deadlocks waiting for a thread that was already killed (T147).

This change causes the `QDBusServiceWatcher` to be deleted before the driver is unloaded.

Reviewers: #swift_pilot_client, kbasan, rwinklmeier

Reviewed By: #swift_pilot_client, kbasan, rwinklmeier

Subscribers: kbasan, jenkins

Tags: #swift_pilot_client

Differential Revision: https://dev.swift-project.org/D50
---
 src/plugins/simulator/xplane/simulatorxplane.cpp | 15 +++++++++++----
 src/plugins/simulator/xplane/simulatorxplane.h   |  1 +
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/plugins/simulator/xplane/simulatorxplane.cpp b/src/plugins/simulator/xplane/simulatorxplane.cpp
index 328bfe2b7..1df81812a 100644
--- a/src/plugins/simulator/xplane/simulatorxplane.cpp
+++ b/src/plugins/simulator/xplane/simulatorxplane.cpp
@@ -113,6 +113,13 @@ namespace BlackSimPlugin
             resetData();
         }
 
+        void CSimulatorXPlane::unload()
+        {
+            CSimulatorCommon::unload();
+            delete m_watcher;
+            m_watcher = nullptr;
+        }
+
         // convert xplane squawk mode to swift squawk mode
         BlackMisc::Aviation::CTransponder::TransponderMode xpdrMode(int xplaneMode, bool ident)
         {
@@ -255,7 +262,7 @@ namespace BlackSimPlugin
                 connect(m_traffic, &CXSwiftBusTrafficProxy::installedModelsUpdated, this, &CSimulatorXPlane::ps_installedModelsUpdated);
                 m_service->updateAirportsInRange();
                 m_traffic->updateInstalledModels();
-                m_watcher->setConnection(m_conn);
+                if (m_watcher) { m_watcher->setConnection(m_conn); }
                 loadCslPackages();
                 emitSimulatorCombinedStatus();
                 return true;
@@ -276,7 +283,7 @@ namespace BlackSimPlugin
             }
 
             m_conn = QDBusConnection { "default" };
-            m_watcher->setConnection(m_conn);
+            if (m_watcher) { m_watcher->setConnection(m_conn); }
             delete m_service;
             delete m_traffic;
             delete m_weather;
@@ -290,7 +297,7 @@ namespace BlackSimPlugin
         void CSimulatorXPlane::ps_serviceUnregistered()
         {
             m_conn = QDBusConnection { "default" };
-            m_watcher->setConnection(m_conn);
+            if (m_watcher) { m_watcher->setConnection(m_conn); }
             delete m_service;
             delete m_traffic;
             delete m_weather;
@@ -746,7 +753,7 @@ namespace BlackSimPlugin
         {
             if (m_watcher)
             {
-                m_watcher->deleteLater();
+                delete m_watcher;
                 m_watcher = nullptr;
             }
         }
diff --git a/src/plugins/simulator/xplane/simulatorxplane.h b/src/plugins/simulator/xplane/simulatorxplane.h
index 6f81d43c4..69022e98f 100644
--- a/src/plugins/simulator/xplane/simulatorxplane.h
+++ b/src/plugins/simulator/xplane/simulatorxplane.h
@@ -100,6 +100,7 @@ namespace BlackSimPlugin
             virtual bool setTimeSynchronization(bool enable, const BlackMisc::PhysicalQuantities::CTime &offset) override;
             virtual BlackMisc::PhysicalQuantities::CTime getTimeSynchronizationOffset() const override { return BlackMisc::PhysicalQuantities::CTime(0, BlackMisc::PhysicalQuantities::CTimeUnit::hrmin()); }
             virtual bool setInterpolatorMode(BlackMisc::Simulation::CInterpolatorMulti::Mode mode, const BlackMisc::Aviation::CCallsign &callsign) override;
+            virtual void unload() override;
             //! @}
 
             //! Creates an appropriate dbus connection from the string describing it