Qt: OpenIGTLink: handle client connection

No disconnect detection yet, though. It seems as if disconnects can
only be detected by reading from the client and having that fail?

Author: ClaudioHoffmann

examples/solum_qt/solum/openigtlink.cpp

@@ -1,19 +1,53 @@
 #include "openigtlink.h"
 
+SolumIGTL::SolumIGTL()
+{
+    QObject::connect(&clientConnectTimer_, &QTimer::timeout, [this]()
+    {
+        client_ = server_->WaitForConnection(1); // 0 would wait forever.
+        if (client_.IsNotNull())
+        {
+            emit clientConnected(true);
+            clientConnectTimer_.stop();
+        }
+    });
+}
+
 bool SolumIGTL::serve(uint16_t port)
 {
     server_ = igtl::ServerSocket::New();
     if (server_->CreateServer(port) < 0)
         return false;
+    reconnectClient();
     return true;
 }
 
 void SolumIGTL::close()
 {
+    disconnectClient();
     server_->CloseSocket();
 }
 
+void SolumIGTL::disconnectClient()
+{
+    clientConnectTimer_.stop();
+    if (client_)
+        client_->CloseSocket();
+    emit clientConnected(false);
+}
+
+void SolumIGTL::reconnectClient()
+{
+    disconnectClient();
+    clientConnectTimer_.start(100);
+}
+
 bool SolumIGTL::isServing() const
 {
     return (server_ && server_->GetConnected());
 }
+
+bool SolumIGTL::isClientConnected() const
+{
+    return (client_ && client_->GetConnected());
+}

examples/solum_qt/solum/openigtlink.h

@@ -8,11 +8,22 @@ class SolumIGTL : public QObject
     Q_OBJECT;
 
 public:
+    SolumIGTL();
+
     bool serve(uint16_t port); /// Returns `false` on failure.
     void close();
 
     bool isServing() const;
+    bool isClientConnected() const;
+
+signals:
+    void clientConnected(bool);
 
 private:
+    void disconnectClient();
+    void reconnectClient();
+
     igtl::ServerSocket::Pointer server_;
+    igtl::Socket::Pointer client_;
+    QTimer clientConnectTimer_;
 };

examples/solum_qt/solum/solumqt.cpp

@@ -301,6 +301,14 @@ Solum::Solum(QWidget *parent) : QMainWindow(parent), imaging_(false)
         }
     });
 
+    connect(&igtl_, &SolumIGTL::clientConnected, [this](bool connected)
+    {
+        if(connected)
+            ui_.igtlStatusClient->setText(tr("🟢 Client connected"));
+        else
+            ui_.igtlStatusClient->setText(tr("⌛ Waiting for client connection…"));
+    });
+
     imagingState(ImagingNotReady, false);
 
     // Automatically trigger a BLE search at startup
@@ -1103,6 +1111,7 @@ void Solum::onIGTLServe()
     {
         igtl_.close();
         ui_.igtlStatusServer->setText(tr("🔴 Server is stopped"));
+        ui_.igtlStatusClient->clear();
         ui_.igtlport->setEnabled(true);
         ui_.igtlserve->setText(tr("Serve"));
     }