1) Enable the 'Configure' and 'View log' menu option when the server taking longer than usual time to start.

2) When an error occurs from the backend, the configure window opens and if the user has changed the setting
   of the port, it won't take any effect as we have retrieved the value of the port at the start of the runtime.
3) Added logic to identify the specified fixed port is already in use. Throw the error before starting the pgAdmin server.

Fixes #5751

runtime/FloatingWindow.cpp

@@ -117,7 +117,6 @@ void FloatingWindow::enableViewLogOption()
         m_logAction->setEnabled(true);
 }
 
-
 // Disable the View Log option
 void FloatingWindow::disableViewLogOption()
 {
@@ -125,6 +124,20 @@ void FloatingWindow::disableViewLogOption()
         m_logAction->setEnabled(false);
 }
 
+// Enable the configure option
+void FloatingWindow::enableConfigOption()
+{
+    if (m_configAction != Q_NULLPTR)
+        m_configAction->setEnabled(true);
+}
+
+// Disable the configure option
+void FloatingWindow::disableConfigOption()
+{
+    if (m_configAction != Q_NULLPTR)
+        m_configAction->setEnabled(false);
+}
+
 void FloatingWindow::closeEvent(QCloseEvent * event)
 {
     // Emit the signal to shut down the python server.

runtime/FloatingWindow.h

@@ -31,6 +31,8 @@ public:
     void enablePostStartOptions();
     void enableViewLogOption();
     void disableViewLogOption();
+    void enableConfigOption();
+    void disableConfigOption();
     void setMenuActions(MenuActions * menuActions);
 
 private:

runtime/Runtime.cpp

@@ -67,10 +67,7 @@ bool Runtime::go(int argc, char *argv[])
     configureProxy();
 
     // Display the spash screen
-    QSplashScreen *splash = displaySplash(&app);
-
-    // Get the port number to use
-    quint16 port = getPort();
+    m_splash = displaySplash(&app);
 
     // Generate a random key to authenticate the client to the server
     QString key = QUuid::createUuid().toString();
@@ -80,29 +77,26 @@ bool Runtime::go(int argc, char *argv[])
     MenuActions *menuActions = new MenuActions();
 
     // Create the control object (tray icon or floating window
-    FloatingWindow *floatingWindow = Q_NULLPTR;
-    TrayIcon *trayIcon = Q_NULLPTR;
-
-    splash->showMessage(QString(QWidget::tr("Checking for system tray...")), Qt::AlignBottom | Qt::AlignCenter);
+    m_splash->showMessage(QString(QWidget::tr("Checking for system tray...")), Qt::AlignBottom | Qt::AlignCenter);
 
     if (QSystemTrayIcon::isSystemTrayAvailable())
-        trayIcon = createTrayIcon(splash, menuActions);
+        m_trayIcon = createTrayIcon(menuActions);
     else
-        floatingWindow = createFloatingWindow(splash, menuActions);
+        m_floatingWindow = createFloatingWindow(menuActions);
 
     // Fire up the app server
-    const Server *server = startServerLoop(splash, floatingWindow, trayIcon, port, key);
+    const Server *server = startServerLoop(key);
 
     // Ensure we'll cleanup
     QObject::connect(server, SIGNAL(finished()), server, SLOT(deleteLater()));
     atexit(cleanup);
 
     // Generate the app server URL
-    QString url = QString("http://127.0.0.1:%1/?key=%2").arg(port).arg(key);
+    QString url = QString("http://127.0.0.1:%1/?key=%2").arg(m_port).arg(key);
     Logger::GetLogger()->Log(QString(QWidget::tr("Application Server URL: %1")).arg(url));
 
     // Check the server is running
-    checkServer(splash, url);
+    checkServer(url);
 
     // Stash the URL for any duplicate processes to open
     createAddressFile(url);
@@ -111,10 +105,10 @@ bool Runtime::go(int argc, char *argv[])
     menuActions->setAppServerUrl(url);
 
     // Enable the shutdown server menu as server started successfully.
-    if (trayIcon != Q_NULLPTR)
-        trayIcon->enablePostStartOptions();
-    if (floatingWindow != Q_NULLPTR)
-        floatingWindow->enablePostStartOptions();
+    if (m_trayIcon != Q_NULLPTR)
+        m_trayIcon->enablePostStartOptions();
+    if (m_floatingWindow != Q_NULLPTR)
+        m_floatingWindow->enablePostStartOptions();
 
     // Open the browser if needed
     if (m_settings.value("OpenTabAtStartup", true).toBool())
@@ -124,10 +118,10 @@ bool Runtime::go(int argc, char *argv[])
     QObject::connect(menuActions, SIGNAL(shutdownSignal(QUrl)), server, SLOT(shutdown(QUrl)));
 
     // Final cleanup
-    splash->finish(Q_NULLPTR);
+    m_splash->finish(Q_NULLPTR);
 
-    if (floatingWindow != Q_NULLPTR)
-        floatingWindow->show();
+    if (m_floatingWindow != Q_NULLPTR)
+        m_floatingWindow->show();
 
     Logger::GetLogger()->Log("Everything works fine, successfully started pgAdmin4.");
     Logger::ReleaseLogger();
@@ -301,11 +295,11 @@ quint16 Runtime::getPort() const
 
 
 // Create a tray icon
-TrayIcon * Runtime::createTrayIcon(QSplashScreen *splash, MenuActions *menuActions)
+TrayIcon * Runtime::createTrayIcon(MenuActions *menuActions)
 {
     TrayIcon *trayIcon = Q_NULLPTR;
 
-    splash->showMessage(QString(QWidget::tr("Checking for system tray...")), Qt::AlignBottom | Qt::AlignCenter);
+    m_splash->showMessage(QString(QWidget::tr("Checking for system tray...")), Qt::AlignBottom | Qt::AlignCenter);
     Logger::GetLogger()->Log("Checking for system tray...");
 
     // Start the tray service
@@ -322,11 +316,11 @@ TrayIcon * Runtime::createTrayIcon(QSplashScreen *splash, MenuActions *menuActio
 
 
 // Create a floating window
-FloatingWindow * Runtime::createFloatingWindow(QSplashScreen *splash, MenuActions *menuActions)
+FloatingWindow * Runtime::createFloatingWindow(MenuActions *menuActions)
 {
     FloatingWindow *floatingWindow = Q_NULLPTR;
 
-    splash->showMessage(QString(QWidget::tr("System tray not found, creating floating window...")), Qt::AlignBottom | Qt::AlignCenter);
+    m_splash->showMessage(QString(QWidget::tr("System tray not found, creating floating window...")), Qt::AlignBottom | Qt::AlignCenter);
     Logger::GetLogger()->Log("System tray not found, creating floating window...");
     floatingWindow = new FloatingWindow();
     if (floatingWindow == Q_NULLPTR)
@@ -345,16 +339,81 @@ FloatingWindow * Runtime::createFloatingWindow(QSplashScreen *splash, MenuAction
     return floatingWindow;
 }
 
+bool Runtime::isPortInUse(const quint16 port)
+{
+    QTcpSocket socket;
+
+    // Bind the socket on the specified port. It it fails then
+    // port is in use.
+    bool bindSuccessful = socket.bind(port, QTcpSocket::ShareAddress);
+
+    return !bindSuccessful;
+}
+
+void Runtime::openConfigureWindow(const QString errorMsg)
+{
+    m_splash->finish(Q_NULLPTR);
+
+    qDebug() << errorMsg;
+    QMessageBox::critical(Q_NULLPTR, QString(QWidget::tr("Fatal Error")), errorMsg);
+    Logger::GetLogger()->Log(errorMsg);
+
+    // Allow the user to tweak the configuration if needed
+    m_configDone = false;
+    bool oldFixedPort = m_settings.value("FixedPort", false).toBool();
+
+
+    ConfigWindow *dlg = new ConfigWindow();
+    dlg->setAttribute(Qt::WA_DeleteOnClose);
+    dlg->show();
+    dlg->raise();
+    dlg->activateWindow();
+    QObject::connect(dlg, SIGNAL(closing(bool)), this, SLOT(onConfigDone(bool)));
+
+    // Wait for configuration to be completed
+    while (!m_configDone)
+        delay(100);
+
+    // Read the value of port again if user has changed.
+    bool newFixedPort = m_settings.value("FixedPort", false).toBool();
+    quint16 newPort = m_settings.value("PortNumber").toInt();
+
+    // User hasn't changed the value of fixed port check box
+    // only change the value of the port
+    if (oldFixedPort == newFixedPort && newFixedPort && m_port != newPort)
+        m_port = newPort;
+    // User has selected the fixed port and it's old value is random port,
+    // so port needs to be updated.
+    else if (oldFixedPort != newFixedPort && newFixedPort)
+        m_port = newPort;
+    // User has deselect the fixed port and it's old value is fixed port,
+    // so we will have to get the random port
+    else if (oldFixedPort != newFixedPort && !newFixedPort)
+        m_port = getPort();
+}
 
 // Server startup loop
-Server * Runtime::startServerLoop(QSplashScreen *splash, FloatingWindow *floatingWindow, TrayIcon *trayIcon, quint16 port, QString key)
+Server * Runtime::startServerLoop(QString key)
 {
     bool done = false;
     Server *server;
 
+    // Get the port number to use
+    m_port = getPort();
+
     while (!done)
     {
-        server = startServer(splash, port, key);
+        if (isPortInUse(m_port))
+        {
+            QString error = QString(QWidget::tr("The specified port is already in use."));
+
+            // Open the configuration window
+            openConfigureWindow(error);
+
+            continue;
+        }
+
+        server = startServer(key);
         if (server == NULL)
         {
             Logger::ReleaseLogger();
@@ -364,41 +423,24 @@ Server * Runtime::startServerLoop(QSplashScreen *splash, FloatingWindow *floatin
         // Check for server startup errors
         if (server->isFinished() || server->getError().length() > 0)
         {
-            splash->finish(Q_NULLPTR);
-
-            qDebug() << server->getError();
-
             QString error = QString(QWidget::tr("An error occurred initialising the pgAdmin 4 server:\n\n%1")).arg(server->getError());
-            QMessageBox::critical(Q_NULLPTR, QString(QWidget::tr("Fatal Error")), error);
-            Logger::GetLogger()->Log(error);
 
             delete server;
 
             // Enable the View Log option for diagnostics
-            if (floatingWindow)
-                floatingWindow->enableViewLogOption();
-            if (trayIcon)
-                trayIcon->enableViewLogOption();
+            if (m_floatingWindow)
+                m_floatingWindow->enableViewLogOption();
+            if (m_trayIcon)
+                m_trayIcon->enableViewLogOption();
 
-            // Allow the user to tweak the Python Path if needed
-            m_configDone = false;
-
-            ConfigWindow *dlg = new ConfigWindow();
-            dlg->setAttribute(Qt::WA_DeleteOnClose);
-            dlg->show();
-            dlg->raise();
-            dlg->activateWindow();
-            QObject::connect(dlg, SIGNAL(closing(bool)), this, SLOT(onConfigDone(bool)));
-
-            // Wait for configuration to be completed
-            while (!m_configDone)
-                delay(100);
+            // Open the configuration window
+            openConfigureWindow(error);
 
             // Disable the View Log option again
-            if (floatingWindow)
-                floatingWindow->disableViewLogOption();
-            if (trayIcon)
-                trayIcon->disableViewLogOption();
+            if (m_floatingWindow)
+                m_floatingWindow->disableViewLogOption();
+            if (m_trayIcon)
+                m_trayIcon->disableViewLogOption();
         }
         else
         {
@@ -422,21 +464,21 @@ void Runtime::onConfigDone(bool accepted)
 
 
 // Start the server
-Server * Runtime::startServer(QSplashScreen *splash, quint16 port, QString key)
+Server * Runtime::startServer(QString key)
 {
     Server *server;
 
-    splash->showMessage(QString(QWidget::tr("Starting pgAdmin4 server...")), Qt::AlignBottom | Qt::AlignCenter);
+    m_splash->showMessage(QString(QWidget::tr("Starting pgAdmin4 server...")), Qt::AlignBottom | Qt::AlignCenter);
     Logger::GetLogger()->Log("Starting pgAdmin4 server...");
 
-    QString msg = QString(QWidget::tr("Creating server object, port:%1, key:%2, logfile:%3")).arg(port).arg(key).arg(g_serverLogFile);
+    QString msg = QString(QWidget::tr("Creating server object, port:%1, key:%2, logfile:%3")).arg(m_port).arg(key).arg(g_serverLogFile);
     Logger::GetLogger()->Log(msg);
-    server = new Server(this, port, key, g_serverLogFile);
+    server = new Server(this, m_port, key, g_serverLogFile);
 
     Logger::GetLogger()->Log("Initializing server...");
     if (!server->Init())
     {
-        splash->finish(Q_NULLPTR);
+        m_splash->finish(Q_NULLPTR);
 
         qDebug() << server->getError();
 
@@ -464,7 +506,7 @@ Server * Runtime::startServer(QSplashScreen *splash, quint16 port, QString key)
 
 
 // Check the server is running properly
-void Runtime::checkServer(QSplashScreen *splash, QString url)
+void Runtime::checkServer(QString url)
 {
     // Read the server connection timeout from the registry or set the default timeout.
     int timeout = m_settings.value("ConnectionTimeout", 90).toInt();
@@ -476,6 +518,7 @@ void Runtime::checkServer(QSplashScreen *splash, QString url)
     QTime midTime1 = QTime::currentTime().addSecs(timeout/3);
     QTime midTime2 = QTime::currentTime().addSecs(timeout*2/3);
     bool alive = false;
+    bool enableOptions = false;
 
     Logger::GetLogger()->Log("The server should be up. Attempting to connect and get a response.");
     while(QTime::currentTime() <= endTime)
@@ -489,12 +532,26 @@ void Runtime::checkServer(QSplashScreen *splash, QString url)
 
         if(QTime::currentTime() >= midTime1)
         {
+            if (m_floatingWindow && !enableOptions)
+            {
+                m_floatingWindow->enableViewLogOption();
+                m_floatingWindow->enableConfigOption();
+                enableOptions = true;
+            }
+
+            if (m_trayIcon && !enableOptions)
+            {
+                m_trayIcon->enableViewLogOption();
+                m_trayIcon->enableConfigOption();
+                enableOptions = true;
+            }
+
             if(QTime::currentTime() < midTime2) {
-                splash->showMessage(QString(QWidget::tr("Taking longer than usual...")), Qt::AlignBottom | Qt::AlignCenter);
+                m_splash->showMessage(QString(QWidget::tr("Taking longer than usual...")), Qt::AlignBottom | Qt::AlignCenter);
             }
             else
             {
-                splash->showMessage(QString(QWidget::tr("Almost there...")), Qt::AlignBottom | Qt::AlignCenter);
+                m_splash->showMessage(QString(QWidget::tr("Almost there...")), Qt::AlignBottom | Qt::AlignCenter);
             }
         }
 
@@ -505,7 +562,7 @@ void Runtime::checkServer(QSplashScreen *splash, QString url)
     Logger::GetLogger()->Log("Attempt to connect one more time in case of a long network timeout while looping");
     if (!alive && !pingServer(QUrl(url)))
     {
-        splash->finish(Q_NULLPTR);
+        m_splash->finish(Q_NULLPTR);
         QString error(QWidget::tr("The pgAdmin 4 server could not be contacted."));
         QMessageBox::critical(Q_NULLPTR, QString(QWidget::tr("Fatal Error")), error);
 

runtime/Runtime.h

@@ -43,20 +43,26 @@ private:
     QSettings m_settings;
     QSharedMemory *m_shmem;
     bool m_configDone;
+    FloatingWindow *m_floatingWindow = Q_NULLPTR;
+    TrayIcon *m_trayIcon = Q_NULLPTR;
+    QSplashScreen *m_splash = Q_NULLPTR;
+    quint16 m_port = 0;
 
     void setupStyling(QApplication *app) const;
     void configureProxy() const;
     QSplashScreen *displaySplash(QApplication *app);
     quint16 getPort() const;
-    TrayIcon *createTrayIcon(QSplashScreen *splash, MenuActions *menuActions);
-    FloatingWindow *createFloatingWindow(QSplashScreen *splash, MenuActions *menuActions);
-    Server *startServerLoop(QSplashScreen *splash, FloatingWindow *floatingWindow, TrayIcon *trayIcon, quint16 port, QString key);
-    Server *startServer(QSplashScreen *splash, quint16 port, QString key);
-    void checkServer(QSplashScreen *splash, QString url);
+    TrayIcon *createTrayIcon(MenuActions *menuActions);
+    FloatingWindow *createFloatingWindow(MenuActions *menuActions);
+    Server *startServerLoop(QString key);
+    Server *startServer(QString key);
+    void checkServer(QString url);
     void createAddressFile(QString url) const;
     void openBrowserTab(QString url) const;
     QString serverRequest(QUrl url, QString path);
     bool pingServer(QUrl url);
+    bool isPortInUse(const quint16 port);
+    void openConfigureWindow(const QString errorMsg);
 
 private slots:
     void onConfigDone(bool accepted);

runtime/TrayIcon.cpp

@@ -116,7 +116,6 @@ void TrayIcon::enableViewLogOption()
         m_logAction->setEnabled(true);
 }
 
-
 // Disable the View Log option
 void TrayIcon::disableViewLogOption()
 {
@@ -124,6 +123,20 @@ void TrayIcon::disableViewLogOption()
         m_logAction->setEnabled(false);
 }
 
+// Enable the configure option
+void TrayIcon::enableConfigOption()
+{
+    if (m_configAction != Q_NULLPTR)
+        m_configAction->setEnabled(true);
+}
+
+// Disable the configure option
+void TrayIcon::disableConfigOption()
+{
+    if (m_configAction != Q_NULLPTR)
+        m_configAction->setEnabled(false);
+}
+
 void TrayIcon::setMenuActions(MenuActions * menuActions)
 {
     m_menuActions = menuActions;

runtime/TrayIcon.h

@@ -28,6 +28,8 @@ public:
     void enablePostStartOptions();
     void enableViewLogOption();
     void disableViewLogOption();
+    void enableConfigOption();
+    void disableConfigOption();
     void setMenuActions(MenuActions * menuActions);
 
 private: