From 742c180967cefc15413ba03ddaf9778e931dbe89 Mon Sep 17 00:00:00 2001
From: Bill Somerville <bill@classdesign.com>
Date: Fri, 6 Nov 2020 01:28:19 +0000
Subject: [PATCH] Allow message_aggregator example to not join on he loopback
 interface

---
 UDPExamples/MessageAggregatorMainWindow.cpp | 41 ++++++++++++++++++---
 UDPExamples/MessageAggregatorMainWindow.hpp |  2 +
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/UDPExamples/MessageAggregatorMainWindow.cpp b/UDPExamples/MessageAggregatorMainWindow.cpp
index a0fe90c47..63b1e45b5 100644
--- a/UDPExamples/MessageAggregatorMainWindow.cpp
+++ b/UDPExamples/MessageAggregatorMainWindow.cpp
@@ -107,13 +107,16 @@ MessageAggregatorMainWindow::MessageAggregatorMainWindow ()
       auto flags = QNetworkInterface::IsRunning | QNetworkInterface::CanMulticast;
       if ((net_if.flags () & flags) == flags)
         {
-          auto is_loopback = net_if.flags () & QNetworkInterface::IsLoopBack;
+          if (net_if.flags () & QNetworkInterface::IsLoopBack)
+            {
+              loopback_interface_name_ = net_if.name ();
+            }
           auto item = network_interfaces_combo_box_->addCheckItem (net_if.humanReadableName ()
                                                                    , net_if.name ()
-                                                                   , is_loopback ? Qt::Checked : Qt::Unchecked);
-          item->setEnabled (!is_loopback);
-          auto tip = QString {"name(index): %1(%2) - %3"}.arg (net_if.name ()).arg (net_if.index ())
-                                                            .arg (net_if.flags () & QNetworkInterface::IsUp ? "Up" : "Down");
+                                                                   , Qt::Unchecked);
+          auto tip = QString {"name(index): %1(%2) - %3"}
+            .arg (net_if.name ()).arg (net_if.index ())
+            .arg (net_if.flags () & QNetworkInterface::IsUp ? "Up" : "Down");
           auto hw_addr = net_if.hardwareAddress ();
           if (hw_addr.size ())
             {
@@ -131,6 +134,8 @@ MessageAggregatorMainWindow::MessageAggregatorMainWindow ()
           item->setToolTip (tip);
         }
     }
+  connect (network_interfaces_combo_box_, &QComboBox::currentTextChanged, this, &MessageAggregatorMainWindow::validate_network_interfaces);
+  validate_network_interfaces (QString {});
 
   log_table_view_->setModel (log_);
   log_table_view_->verticalHeader ()->hide ();
@@ -369,4 +374,30 @@ void MessageAggregatorMainWindow::change_highlighting (QString const& call, QCol
     }
 }
 
+void MessageAggregatorMainWindow::validate_network_interfaces (QString const& /*text*/)
+{
+  auto model = static_cast<QStandardItemModel *> (network_interfaces_combo_box_->model ());
+  bool has_checked {false};
+  int loopback_row {-1};
+  for (int row = 0; row < model->rowCount (); ++row)
+    {
+      if (model->item (row)->data ().toString () == loopback_interface_name_)
+        {
+          loopback_row = row;
+        }
+      else if (Qt::Checked == model->item (row)->checkState ())
+        {
+          has_checked = true;
+        }
+    }
+  if (loopback_row >= 0)
+    {
+      if (!has_checked)
+        {
+          model->item (loopback_row)->setCheckState (Qt::Checked);
+        }
+      model->item (loopback_row)->setEnabled (has_checked);
+    }
+}
+
 #include "moc_MessageAggregatorMainWindow.cpp"
diff --git a/UDPExamples/MessageAggregatorMainWindow.hpp b/UDPExamples/MessageAggregatorMainWindow.hpp
index 1bff0d692..71ab89ffe 100644
--- a/UDPExamples/MessageAggregatorMainWindow.hpp
+++ b/UDPExamples/MessageAggregatorMainWindow.hpp
@@ -46,6 +46,7 @@ private:
   void remove_client (ClientKey const&);
   void change_highlighting (QString const& call, QColor const& bg = QColor {}, QColor const& fg = QColor {},
                             bool last_only = false);
+  Q_SLOT void validate_network_interfaces (QString const&);
 
   // maps client id to widgets
   using ClientsDictionary = QHash<ClientKey, ClientWidget *>;
@@ -59,6 +60,7 @@ private:
   QSpinBox * port_spin_box_;
   QLineEdit * multicast_group_line_edit_;
   CheckableItemComboBox * network_interfaces_combo_box_;
+  QString loopback_interface_name_;
   QLabel * network_interfaces_form_label_widget_;
   QTableView * log_table_view_;
   QListWidget * calls_of_interest_;