Review comments: redo notifiers as QPointers

Summary:
IPv6 is supported by LibVNCServer but for compatibility reasons its
socket is backed by another file descriptor.

This commit adds tracking IPv6 listen socket in the same way we now
track IPv4 one.

Differential Revision: https://phabricator.kde.org/D13209

krfb/rfbserver.cpp

@@ -22,6 +22,7 @@
 #include <QtCore/QSocketNotifier>
 #include <QApplication>
 #include <QClipboard>
+#include <QPointer>
 #include <QDebug>
 
 struct RfbServer::Private
@@ -30,7 +31,8 @@ struct RfbServer::Private
     int listeningPort;
     bool passwordRequired;
     rfbScreenInfoPtr screen;
-    QSocketNotifier *notifier;
+    QPointer<QSocketNotifier> ipv4notifier;
+    QPointer<QSocketNotifier> ipv6notifier;
 };
 
 RfbServer::RfbServer(QObject *parent)
@@ -40,7 +42,6 @@ RfbServer::RfbServer(QObject *parent)
     d->listeningPort = 0;
     d->passwordRequired = true;
     d->screen = NULL;
-    d->notifier = NULL;
 
     RfbServerManager::instance()->registerServer(this);
 }
@@ -135,9 +136,13 @@ bool RfbServer::start()
         return false;
     };
 
-    d->notifier = new QSocketNotifier(d->screen->listenSock, QSocketNotifier::Read, this);
-    d->notifier->setEnabled(true);
-    connect(d->notifier, &QSocketNotifier::activated, this, &RfbServer::onListenSocketActivated);
+    d->ipv4notifier = new QSocketNotifier(d->screen->listenSock, QSocketNotifier::Read, this);
+    connect(d->ipv4notifier, &QSocketNotifier::activated, this, &RfbServer::onListenSocketActivated);
+    if (d->screen->listen6Sock > 0) {
+        // we're also listening on additional IPv6 socket, get events from there
+        d->ipv6notifier = new QSocketNotifier(d->screen->listen6Sock, QSocketNotifier::Read, this);
+        connect(d->ipv6notifier, &QSocketNotifier::activated, this, &RfbServer::onListenSocketActivated);
+    }
     connect(QApplication::clipboard(), &QClipboard::dataChanged,
             this, &RfbServer::krfbSendServerCutText);
 
@@ -148,10 +153,11 @@ void RfbServer::stop()
 {
     if (d->screen) {
         rfbShutdownServer(d->screen, true);
-        if (d->notifier) {
-            d->notifier->setEnabled(false);
-            d->notifier->deleteLater();
-            d->notifier = NULL;
+        for (auto notifier : {d->ipv4notifier, d->ipv6notifier}) {
+            if (notifier) {
+                notifier->setEnabled(false);
+                notifier->deleteLater();
+            }
         }
     }
 }