Log old session out of server if logging in from a second location

cockatrice/src/window_main.cpp

@@ -85,6 +85,7 @@ void MainWindow::processConnectionClosedEvent(const Event_ConnectionClosed &even
         }
         case Event_ConnectionClosed::SERVER_SHUTDOWN: reasonStr = tr("Scheduled server shutdown."); break;
         case Event_ConnectionClosed::USERNAMEINVALID: reasonStr = tr("Invalid username."); break;
+        case Event_ConnectionClosed::LOGGEDINELSEWERE: reasonStr = tr("You have been logged out due to logging in at another location."); break;
         default: reasonStr = QString::fromStdString(event.reason_str());
     }
     QMessageBox::critical(this, tr("Connection closed"), tr("The server has terminated your connection.\nReason: %1").arg(reasonStr));

common/pb/event_connection_closed.proto

@@ -12,6 +12,7 @@ message Event_ConnectionClosed {
 		USERNAMEINVALID = 5;
 		USER_LIMIT_REACHED = 6;
 		DEMOTED = 7;
+		LOGGEDINELSEWERE = 8;
 	}
 	optional CloseReason reason = 1;
 	optional string reason_str = 2;

common/server.cpp

@@ -30,6 +30,7 @@
 #include "pb/event_user_left.pb.h"
 #include "pb/event_list_rooms.pb.h"
 #include "pb/session_event.pb.h"
+#include "pb/event_connection_closed.pb.h"
 #include "pb/isl_message.pb.h"
 #include <QCoreApplication>
 #include <QThread>
@@ -126,9 +127,17 @@ AuthenticationResult Server::loginUser(Server_ProtocolHandler *session, QString
 
         // verify that new session would not cause problems with older existing session
         if (users.contains(name) || databaseInterface->userSessionExists(name)) {
-            qDebug("Login denied: would overwrite old session");
-            databaseInterface->unlockSessionTables();
-            return WouldOverwriteOldSession;
+            qDebug("Session already logged in, logging old session out");
+
+            Event_ConnectionClosed event;
+            event.set_reason(Event_ConnectionClosed::LOGGEDINELSEWERE);
+            event.set_reason_str("You have been logged out due to logging in at another location.");
+            event.set_end_time(QDateTime::currentDateTime().toTime_t());
+
+            SessionEvent *se = users.value(name)->prepareSessionEvent(event);
+            users.value(name)->sendProtocolItem(*se);
+            delete se;
+
         }
     } else if (authState == UnknownUser) {
         // Change user name so that no two users have the same names,