Highlander code

4 files changed, 109 insertions, 4 deletions

diff --git a/main.cpp b/main.cpp
index d4a97f7e..87df4ade 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,10 +1,14 @@
 #include "mainwindow.h"
 #include <QApplication>
 #include <QTranslator>
+#include "singleapplication.h"
 
 int main(int argc, char *argv[])
 {
-    QApplication app(argc, argv);
+    SingleApplication app(argc, argv, "QtPass");
+    if (app.isRunning()) {
+        return 0;
+    }
    
     QCoreApplication::setOrganizationName("IJHack");
     QCoreApplication::setOrganizationDomain("ijhack.org");
diff --git a/qtpass.pro b/qtpass.pro
index fe4f0278..e81e24bc 100644
--- a/qtpass.pro
+++ b/qtpass.pro
@@ -4,7 +4,7 @@
 #
 #-------------------------------------------------
 
-QT        += core gui
+QT        += core gui network
 
 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
@@ -19,11 +19,13 @@ TEMPLATE   = app
 SOURCES   += main.cpp\
              mainwindow.cpp \
              dialog.cpp \
-             storemodel.cpp
+             storemodel.cpp \
+             singleapplication.cpp
 
 HEADERS   += mainwindow.h \
              dialog.h \
-             storemodel.h
+             storemodel.h \
+             singleapplication.h
 
 FORMS     += mainwindow.ui \
              dialog.ui
diff --git a/singleapplication.cpp b/singleapplication.cpp
new file mode 100644
index 00000000..fc668f97
--- /dev/null
+++ b/singleapplication.cpp
@@ -0,0 +1,68 @@
+#include <QLocalSocket>
+
+#include "singleapplication.h"
+
+SingleApplication::SingleApplication(int &argc, char *argv[], const QString uniqueKey) : QApplication(argc, argv), _uniqueKey(uniqueKey)
+{
+        sharedMemory.setKey(_uniqueKey);
+        if (sharedMemory.attach())
+                _isRunning = true;
+        else
+        {
+                _isRunning = false;
+                // create shared memory.
+                if (!sharedMemory.create(1))
+                {
+                        qDebug("Unable to create single instance.");
+                        return;
+                }
+                // create local server and listen to incomming messages from other instances.
+                localServer = new QLocalServer(this);
+                connect(localServer, SIGNAL(newConnection()), this, SLOT(receiveMessage()));
+                localServer->listen(_uniqueKey);
+        }
+}
+
+// public slots.
+
+void SingleApplication::receiveMessage()
+{
+        QLocalSocket *localSocket = localServer->nextPendingConnection();
+        if (!localSocket->waitForReadyRead(timeout))
+        {
+                qDebug() << localSocket->errorString().toLatin1();
+                return;
+        }
+        QByteArray byteArray = localSocket->readAll();
+        QString message = QString::fromUtf8(byteArray.constData());
+        emit messageAvailable(message);
+        localSocket->disconnectFromServer();
+}
+
+// public functions.
+
+bool SingleApplication::isRunning()
+{
+        return _isRunning;
+}
+
+bool SingleApplication::sendMessage(const QString &message)
+{
+        if (!_isRunning)
+                return false;
+        QLocalSocket localSocket(this);
+        localSocket.connectToServer(_uniqueKey, QIODevice::WriteOnly);
+        if (!localSocket.waitForConnected(timeout))
+        {
+                qDebug() << localSocket.errorString().toLatin1();
+                return false;
+        }
+        localSocket.write(message.toUtf8());
+        if (!localSocket.waitForBytesWritten(timeout))
+        {
+                qDebug() << localSocket.errorString().toLatin1();
+                return false;
+        }
+        localSocket.disconnectFromServer();
+        return true;
+}
diff --git a/singleapplication.h b/singleapplication.h
new file mode 100644
index 00000000..85c5f609
--- /dev/null
+++ b/singleapplication.h
@@ -0,0 +1,31 @@
+#ifndef SINGLE_APPLICATION_H
+#define SINGLE_APPLICATION_H
+
+#include <QApplication>
+#include <QSharedMemory>
+#include <QLocalServer>
+
+class SingleApplication : public QApplication
+{
+        Q_OBJECT
+public:
+        SingleApplication(int &argc, char *argv[], const QString uniqueKey);
+
+        bool isRunning();
+        bool sendMessage(const QString &message);
+
+public slots:
+        void receiveMessage();
+
+signals:
+        void messageAvailable(QString message);
+
+private:
+        bool _isRunning;
+        QString _uniqueKey;
+        QSharedMemory sharedMemory;
+        QLocalServer *localServer;
+
+        static const int timeout = 1000;
+};
+#endif // SINGLE_APPLICATION_H