From 68823adda3c8838733baea2405a75511baffe172 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jaakko=20Ker=C3=A4nen?= <jaakko.keranen@iki.fi>
Date: Tue, 7 Jul 2015 21:20:31 +0300
Subject: [PATCH] Fixed|Client: Null pointer access if shutting down too early

The input system may be missing when an error occurs.
---
 doomsday/apps/client/include/clientapp.h | 1 +
 doomsday/apps/client/src/clientapp.cpp   | 7 ++++++-
 doomsday/apps/client/src/sys_system.cpp  | 6 +++++-
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/doomsday/apps/client/include/clientapp.h b/doomsday/apps/client/include/clientapp.h
index 80d8b61e79..b1f583e53a 100644
--- a/doomsday/apps/client/include/clientapp.h
+++ b/doomsday/apps/client/include/clientapp.h
@@ -76,6 +76,7 @@ class ClientApp : public de::BaseGuiApp
     static de::Games &games();
     static de::WorldSystem &worldSystem();
 
+    static bool hasInputSystem();
     static bool hasRenderSystem();
 
 public slots:
diff --git a/doomsday/apps/client/src/clientapp.cpp b/doomsday/apps/client/src/clientapp.cpp
index f5b2934268..f23d1aa0d5 100644
--- a/doomsday/apps/client/src/clientapp.cpp
+++ b/doomsday/apps/client/src/clientapp.cpp
@@ -504,6 +504,11 @@ InputSystem &ClientApp::inputSystem()
     return *a.d->inputSys;
 }
 
+bool ClientApp::hasInputSystem()
+{
+    return ClientApp::app().d->inputSys != nullptr;
+}
+
 RenderSystem &ClientApp::renderSystem()
 {
     ClientApp &a = ClientApp::app();
@@ -513,7 +518,7 @@ RenderSystem &ClientApp::renderSystem()
 
 bool ClientApp::hasRenderSystem()
 {
-    return ClientApp::app().d->rendSys != 0;
+    return ClientApp::app().d->rendSys != nullptr;
 }
 
 ResourceSystem &ClientApp::resourceSystem()
diff --git a/doomsday/apps/client/src/sys_system.cpp b/doomsday/apps/client/src/sys_system.cpp
index 81820dc46d..34e6ad1f9c 100644
--- a/doomsday/apps/client/src/sys_system.cpp
+++ b/doomsday/apps/client/src/sys_system.cpp
@@ -134,9 +134,13 @@ void Sys_Shutdown()
     // Let's shut down sound first, so Windows' HD-hogging doesn't jam
     // the MUS player (would produce horrible bursts of notes).
     S_Shutdown();
+    
 #ifdef __CLIENT__
     GL_Shutdown();
-    ClientApp::inputSystem().clearEvents();
+    if(ClientApp::hasInputSystem())
+    {
+        ClientApp::inputSystem().clearEvents();
+    }
 #endif
 
     App_ClearGames();