QAbstractSocket: virtualize options setting

Some kinds of socket options can be applied only to newly created
descriptors. However, a current QAbstractSocket implementation proceeds
to actions immediately after the socket layer initialization. This
disallows a socket tuning in further inheritance.

Add a private virtual configureCreatedSocket() method that gives an
ability to set the socket options before binding or connecting.

Change-Id: I2d858a400cd46ae7fe5bf0b8900220f6121d0132
Reviewed-by: Richard J. Moore <rich@kde.org>

src/network/socket/qabstractsocket.cpp

@@ -650,6 +650,8 @@ bool QAbstractSocketPrivate::initSocketLayer(QAbstractSocket::NetworkLayerProtoc
         return false;
     }
 
+    configureCreatedSocket();
+
     if (threadData->hasEventDispatcher())
         socketEngine->setReceiver(this);
 
@@ -660,6 +662,12 @@ bool QAbstractSocketPrivate::initSocketLayer(QAbstractSocket::NetworkLayerProtoc
     return true;
 }
 
+/*! \internal
+*/
+void QAbstractSocketPrivate::configureCreatedSocket()
+{
+}
+
 /*! \internal
 
     Slot connected to the read socket notifier. This slot is called

src/network/socket/qabstractsocket_p.h

@@ -130,6 +130,7 @@ public:
     bool flush();
 
     bool initSocketLayer(QAbstractSocket::NetworkLayerProtocol protocol);
+    virtual void configureCreatedSocket();
     void startConnectingByName(const QString &host);
     void fetchConnectionParameters();
     void setupSocketNotifiers();