add single application solution

Rythem.pro

@@ -37,7 +37,8 @@ SOURCES += main.cpp\
     quazip/JlCompress.cpp \
     rytablesortfilterproxymodel.cpp \
     widget/rywebview.cpp \
-    widget/rytabwidget.cpp
+    widget/rytabwidget.cpp \
+    singleapplication.cpp
 
 
 HEADERS  += mainwindow.h \
@@ -70,7 +71,8 @@ HEADERS  += mainwindow.h \
     rymimedata.h \
     rytablesortfilterproxymodel.h \
     widget/rywebview.h \
-    widget/rytabwidget.h
+    widget/rytabwidget.h \
+    singleapplication.h
 win32:HEADERS += zlib/zutil.h \
     zlib/zlib.h \
     zlib/zconf.h \

main.cpp

@@ -16,6 +16,7 @@
 #include <QThread>
 
 #include <QTranslator>
+#include "singleapplication.h"
 
 using namespace rule;
 
@@ -51,7 +52,12 @@ void myMessageHandler(QtMsgType type, const char *msg)
 
 int main(int argc, char *argv[])
 {
-	QApplication a(argc, argv);
+    SingleApplication a(argc, argv, "a");
+    if(a.isRunning()){
+        a.sendMessage("from other instance");
+        return 0;
+    }
+
     a.setQuitOnLastWindowClosed(false);
     appPath =  qApp->applicationDirPath();
 

singleapplication.cpp

@@ -0,0 +1,69 @@
+#include "singleapplication.h"
+
+#include <QLocalSocket>
+
+
+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;
+}

singleapplication.h

@@ -0,0 +1,33 @@
+// "single_application.h"
+
+#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