Merge bitcoin-core/gui#375: Emit dataChanged signal to dynamically re-sort Peers table

986bf78d7e qt: Emit dataChanged signal to dynamically re-sort Peers table (Hennadii Stepanov)

Pull request description:

  [By default](https://doc.qt.io/qt-5/qsortfilterproxymodel.html#details), the `PeerTableSortProxy`
  > dynamically re-sorts ... data whenever the original model changes.

  That is not the case on master (8cdf91735f) as in ecbd911538 (#164) no signals are emitted to notify about model changes.

  This PR uses a dedicated [`dataChanged`](https://doc.qt.io/qt-5/qabstractitemmodel.html#dataChanged) signal.

  Fixes #367.

  An alternative to #374.

ACKs for top commit:
  jarolrod:
    ACK 986bf78d7e

Tree-SHA512: dcb92c2f9a2c632880429e9528007db426d2ad938c64dfa1f1538c03e4b62620df52ad7daf33b582976c67b472ff76bc0dae707049f4bbbd4941232cee9ce3d4

src/qt/peertablemodel.cpp

@@ -179,5 +179,7 @@ void PeerTableModel::refresh()
         m_peers_data.swap(new_peers_data);
     }
 
-    Q_EMIT changed();
+    const auto top_left = index(0, 0);
+    const auto bottom_right = index(rowCount() - 1, columnCount() - 1);
+    Q_EMIT dataChanged(top_left, bottom_right);
 }

src/qt/peertablemodel.h

@@ -73,9 +73,6 @@ public:
 public Q_SLOTS:
     void refresh();
 
-Q_SIGNALS:
-    void changed();
-
 private:
     //! Internal peer data structure.
     QList<CNodeCombinedStats> m_peers_data{};

src/qt/rpcconsole.cpp

@@ -35,6 +35,7 @@
 #endif
 
 #include <QAbstractButton>
+#include <QAbstractItemModel>
 #include <QDateTime>
 #include <QFont>
 #include <QKeyEvent>
@@ -686,7 +687,7 @@ void RPCConsole::setClientModel(ClientModel *model, int bestblock_height, int64_
 
         // peer table signal handling - update peer details when selecting new node
         connect(ui->peerWidget->selectionModel(), &QItemSelectionModel::selectionChanged, this, &RPCConsole::updateDetailWidget);
-        connect(model->getPeerTableModel(), &PeerTableModel::changed, this, &RPCConsole::updateDetailWidget);
+        connect(model->getPeerTableModel(), &QAbstractItemModel::dataChanged, [this] { updateDetailWidget(); });
 
         // set up ban table
         ui->banlistWidget->setModel(model->getBanTableModel());