From 51332b86a118704bc73cae43556b83a4591399b1 Mon Sep 17 00:00:00 2001
From: Marc Bouvier <marcrbouvier@gmail.com>
Date: Tue, 3 Sep 2013 01:44:21 -0500
Subject: [PATCH] [Feature #811] Only 1 Instance of OpenCS is Allowed

If another instance of OpenCS is started, then it will terminate. This
is done by creating a QLocalServer with a unique ID. If another
QLocalServer with the same ID attempts to be opened, then the creation
of the QLocalServer will fail and the application will terminate.
---
 apps/opencs/CMakeLists.txt |  2 +-
 apps/opencs/editor.cpp     | 11 +++++++++++
 apps/opencs/editor.hpp     |  8 ++++++++
 apps/opencs/main.cpp       |  5 +++++
 4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/apps/opencs/CMakeLists.txt b/apps/opencs/CMakeLists.txt
index f7b7daee49..1eb8fd2761 100644
--- a/apps/opencs/CMakeLists.txt
+++ b/apps/opencs/CMakeLists.txt
@@ -127,7 +127,7 @@ if(WIN32)
     set(QT_USE_QTMAIN TRUE)
 endif(WIN32)
 
-find_package(Qt4 COMPONENTS QtCore QtGui QtXml QtXmlPatterns REQUIRED)
+find_package(Qt4 COMPONENTS QtCore QtGui QtNetwork QtXml QtXmlPatterns REQUIRED)
 include(${QT_USE_FILE})
 
 qt4_wrap_ui(OPENCS_UI_HDR ${OPENCS_UI})
diff --git a/apps/opencs/editor.cpp b/apps/opencs/editor.cpp
index e05ebcdeb2..c339d87699 100644
--- a/apps/opencs/editor.cpp
+++ b/apps/opencs/editor.cpp
@@ -2,6 +2,8 @@
 #include "editor.hpp"
 
 #include <QApplication>
+#include <QLocalServer>
+#include <QLocalSocket>
 
 #include "model/doc/document.hpp"
 #include "model/world/data.hpp"
@@ -114,6 +116,15 @@ void CS::Editor::createNewFile()
     mFileDialog.hide();
 }
 
+bool CS::Editor::makeIPCServer()
+{
+	server = new QLocalServer(this);
+	if(server->listen("IPCServer"))
+		return true;
+	server->close();
+	return false;
+}
+
 int CS::Editor::run()
 {
     mStartup.show();
diff --git a/apps/opencs/editor.hpp b/apps/opencs/editor.hpp
index 380e434c24..2d50b68fe3 100644
--- a/apps/opencs/editor.hpp
+++ b/apps/opencs/editor.hpp
@@ -1,6 +1,8 @@
 #ifndef CS_EDITOR_H
 #define CS_EDITOR_H
 
+#include <QLocalServer>
+
 #include <QObject>
 #ifndef Q_MOC_RUN
 #include <components/files/configurationmanager.hpp>
@@ -35,6 +37,8 @@ namespace CS
 
             Editor();
 
+            bool makeIPCServer();
+
             int run();
             ///< \return error status
 
@@ -45,6 +49,10 @@ namespace CS
             void loadDocument();
             void openFiles();
             void createNewFile();
+
+        private:
+
+            QLocalServer *server;
     };
 }
 
diff --git a/apps/opencs/main.cpp b/apps/opencs/main.cpp
index 7f6f9302ed..3e40ee8ccb 100644
--- a/apps/opencs/main.cpp
+++ b/apps/opencs/main.cpp
@@ -39,5 +39,10 @@ int main(int argc, char *argv[])
 
     CS::Editor editor;
 
+    if(!editor.makeIPCServer())
+    {
+    	return 0;
+    }
+
     return editor.run();
 }