Delete disconnected socket

Method onSocketDisconnected has never been called, so WebSocketServer did not
handle closed connection properly. Moreover, socket was not freed in time
and this led to increase in memory consumption

Task-number: QTBUG-56414
Change-Id: Ib57f5b88413ffeef4f296a260245ba0a8d25adb2
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
Reviewed-by: Liang Qi <liang.qi@qt.io>

src/websockets/qwebsocketserver_p.cpp

@@ -392,18 +392,20 @@ void QWebSocketServerPrivate::onNewConnection()
         QObjectPrivate::connect(pTcpSocket, &QTcpSocket::readyRead,
                                 this, &QWebSocketServerPrivate::handshakeReceived,
                                 Qt::QueuedConnection);
+        QObjectPrivate::connect(pTcpSocket, &QTcpSocket::disconnected,
+                                this, &QWebSocketServerPrivate::onSocketDisconnected);
     }
 }
 
 /*!
     \internal
  */
-void QWebSocketServerPrivate::onCloseConnection()
+void QWebSocketServerPrivate::onSocketDisconnected()
 {
     if (Q_LIKELY(currentSender)) {
         QTcpSocket *pTcpSocket = qobject_cast<QTcpSocket*>(currentSender->sender);
         if (Q_LIKELY(pTcpSocket))
-            pTcpSocket->close();
+            pTcpSocket->deleteLater();
     }
 }
 

src/websockets/qwebsocketserver_p.h

@@ -136,7 +136,7 @@ private:
                                  const QString &errorDescription);
 
     void onNewConnection();
-    void onCloseConnection();
+    void onSocketDisconnected();
     void handshakeReceived();
 };