From 607b7cc9ed5bd281eb286dabf3c7fc7998ab214e Mon Sep 17 00:00:00 2001
From: Taylor Richards <taylor@icculus.org>
Date: Thu, 17 Mar 2016 14:42:16 -0400
Subject: [PATCH] add test for existing instance of game (an error condition)

---
 CMakeLists.txt            |  2 +-
 src/network/stand_gui.cpp | 21 ++++++++++++++++++++-
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2b8f3c5..c642ed1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ find_package(OpenGL REQUIRED)
 find_package(OpenAL REQUIRED)
 find_package(LibWebSockets REQUIRED)
 
-find_package(wxWidgets COMPONENTS core base gl)
+find_package(wxWidgets COMPONENTS core base gl net)
 include(${wxWidgets_USE_FILE})
 
 
diff --git a/src/network/stand_gui.cpp b/src/network/stand_gui.cpp
index 74f4f1c..b57b096 100644
--- a/src/network/stand_gui.cpp
+++ b/src/network/stand_gui.cpp
@@ -18,6 +18,7 @@
 #include "wx/msgdlg.h"
 #include "wx/process.h"
 #include "wx/textfile.h"
+#include "wx/socket.h"
 
 #include "SDL.h"
 
@@ -72,7 +73,7 @@ bool StandaloneApp::OnInit()
 			throw "Unable to initialize WebSocket";
 		}
 	} catch (const char *err) {
-		wxMessageBox(err, "Error!");
+		wxMessageBox(err, "Error!", wxOK|wxICON_ERROR|wxCENTRE|wxSTAY_ON_TOP);
 
 		return false;
 	}
@@ -1165,6 +1166,24 @@ bool Standalone::startFreeSpace(int argc, wxCmdLineArgsArray &argv)
 		}
 	}
 
+	// test if socket is in use (in case exising instance is running on same port)
+	wxDatagramSocket *sock;
+	wxIPV4address addr;
+
+	addr.AnyAddress();
+	addr.Service( (unsigned short)fsport );
+
+	sock = new wxDatagramSocket(addr);
+
+	bool isok = sock->IsOk();
+
+	sock->Destroy();
+
+	if ( !isok ) {
+		throw "Unable to start FreeSpace\n\nAn instance is already running";
+	}
+
+	// start game executable
 	fspid = wxExecute(epath, wxEXEC_ASYNC | wxEXEC_MAKE_GROUP_LEADER | wxEXEC_HIDE_CONSOLE);
 
 	return (fspid > 0);
-- 
2.39.2