QSsl: introduce qtls_utils_p.h with simple RAII helpers

Now that I need this stuff both in OpenSSL and woldSSL code, makes sense
to introduce such helpers as a separate change (instead of duplicating
the code in wolfSSL patch).

Change-Id: I9ce600ebe709d103209372ea4c2bdb6fa6b6ce3a
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/network/CMakeLists.txt

@@ -41,7 +41,7 @@ qt_add_module(Network
         socket/qudpsocket.cpp socket/qudpsocket.h
         ssl/qasn1element.cpp ssl/qasn1element_p.h
         ssl/qpassworddigestor.cpp ssl/qpassworddigestor.h
-        ssl/qssl.cpp ssl/qssl.h ssl/qssl_p.h
+        ssl/qssl.cpp ssl/qssl.h ssl/qssl_p.h ssl/qtls_utils_p.h
         ssl/qsslcertificate.cpp ssl/qsslcertificate.h ssl/qsslcertificate_p.h
         ssl/qsslcertificateextension.cpp ssl/qsslcertificateextension.h ssl/qsslcertificateextension_p.h
     DEFINES

src/network/ssl/qtls_utils_p.h

@@ -0,0 +1,99 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtNetwork module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QTLS_UTILS_P_H
+#define QTLS_UTILS_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtNetwork/private/qtnetworkglobal_p.h>
+
+#if QT_CONFIG(openssl)
+#include <QtNetwork/private/qsslsocket_openssl_p.h>
+#endif
+
+#include <QtNetwork/private/qssl_p.h>
+
+#include <QtCore/qglobal.h>
+#include <QtCore/qdebug.h>
+
+#include <memory>
+
+QT_BEGIN_NAMESPACE
+
+namespace QTlslUtils
+{
+
+template <class NativeTlsType, void (*Deleter)(NativeTlsType *)>
+void safe_delete(NativeTlsType *object)
+{
+    if (object && Deleter)
+        Deleter(object);
+}
+
+template<class NativeTlsType, int ok, int (*Deleter)(NativeTlsType *)>
+void safe_delete(NativeTlsType *object)
+{
+    if (Deleter && object) {
+        if (Deleter(object) != ok) {
+            qCWarning(lcSsl, "Failed to free a resource.");
+#if QT_CONFIG(openssl) // || wolfssl later
+            QSslSocketBackendPrivate::logAndClearErrorQueue();
+#endif // QT_CONFIG(openssl)
+        }
+    }
+}
+
+template<class NativeTlsType>
+using Deleter = std::unique_ptr<NativeTlsType, void (*)(NativeTlsType *)>;
+
+} // namespace QTlsUtils
+
+QT_END_NAMESPACE
+
+#endif // QTLS_UTILS_P_H

src/network/ssl/ssl.pri

@@ -1,12 +1,11 @@
-# OpenSSL support; compile in QSslSocket.
-
 HEADERS += ssl/qasn1element_p.h \
            ssl/qssl.h \
            ssl/qssl_p.h \
            ssl/qsslcertificate.h \
            ssl/qsslcertificate_p.h \
            ssl/qsslcertificateextension.h \
-           ssl/qsslcertificateextension_p.h
+           ssl/qsslcertificateextension_p.h \
+           ssl/qtls_utils_p.h
 
 SOURCES += ssl/qasn1element.cpp \
            ssl/qssl.cpp \