Remove QSslSocket::abort()

QAbstractSocket::abort() is not a virtual function and
QSslSocket::abort() does not override it. Having two alternatives
requires a dynamic typecasting and violates the principles of object-
oriented programming.

Due to the BC, we were unable to fix that in Qt5. Now, we can modify
QSslSocket::close() to handle QAbstractSocket::abort() requests and
remove the duplicate.

Change-Id: I49d6f32a571ae6e35b08cb366816f917e580dae8
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

src/network/socket/qabstractsocket.cpp

@@ -479,10 +479,6 @@
 #include <qscopedvaluerollback.h>
 #include <qvarlengtharray.h>
 
-#ifndef QT_NO_SSL
-#include <QtNetwork/qsslsocket.h>
-#endif
-
 #include <private/qthread_p.h>
 
 #ifdef QABSTRACTSOCKET_DEBUG
@@ -2406,13 +2402,6 @@ void QAbstractSocket::abort()
     qDebug("QAbstractSocket::abort()");
 #endif
     d->setWriteChannelCount(0);
-#ifndef QT_NO_SSL
-    if (QSslSocket *socket = qobject_cast<QSslSocket *>(this)) {
-        socket->abort();
-        return;
-    }
-#endif
-
     d->abortCalled = true;
     close();
 }

src/network/ssl/qsslsocket.cpp

@@ -899,13 +899,19 @@ void QSslSocket::close()
 #endif
     Q_D(QSslSocket);
 
-    // We don't want any CA roots fetched anymore.
+    // On Windows, CertGetCertificateChain is probably still doing its
+    // job, if the socket is re-used, we want to ignore its reported
+    // root CA.
     d->caToFetch = QSslCertificate{};
 
-    if (encryptedBytesToWrite() || !d->writeBuffer.isEmpty())
+    if (!d->abortCalled && (encryptedBytesToWrite() || !d->writeBuffer.isEmpty()))
         flush();
-    if (d->plainSocket)
+    if (d->plainSocket) {
+        if (d->abortCalled)
+            d->plainSocket->abort();
+        else
             d->plainSocket->close();
+    }
     QTcpSocket::close();
 
     // must be cleared, reading/writing not possible on closed socket:
@@ -938,29 +944,6 @@ void QSslSocket::setReadBufferSize(qint64 size)
         d->plainSocket->setReadBufferSize(size);
 }
 
-/*!
-    Aborts the current connection and resets the socket. Unlike
-    disconnectFromHost(), this function immediately closes the socket,
-    clearing any pending data in the write buffer.
-
-    \sa disconnectFromHost(), close()
-*/
-void QSslSocket::abort()
-{
-    Q_D(QSslSocket);
-#ifdef QSSLSOCKET_DEBUG
-    qCDebug(lcSsl) << "QSslSocket::abort()";
-#endif
-    // On Windows, CertGetCertificateChain is probably still doing its
-    // job, if the socket is re-used, we want to ignore its reported
-    // root CA.
-    d->caToFetch = QSslCertificate{};
-
-    if (d->plainSocket)
-        d->plainSocket->abort();
-    close();
-}
-
 /*!
     \since 4.4
 
@@ -1883,6 +1866,7 @@ void QSslSocketPrivate::init()
     connectionEncrypted = false;
     ignoreAllSslErrors = false;
     shutdown = false;
+    abortCalled = false;
     pendingClose = false;
     flushTriggered = false;
     ocspResponses.clear();

src/network/ssl/qsslsocket.h

@@ -117,7 +117,6 @@ public:
     bool canReadLine() const override;
     void close() override;
     bool atEnd() const override;
-    void abort();
 
     // From QAbstractSocket:
     void setReadBufferSize(qint64 size) override;