Forward declare types as much as possible

src/app/qtlocalpeer/qtlockedfile.cpp

@@ -1,4 +1,31 @@
-/****************************************************************************
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2019  Mike Tzou (Chocobo1)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), you may extend this exception to your version of the file(s),
+ * but you are not obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ *
+****************************************************************************
 **
 ** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
@@ -36,7 +63,8 @@
 **
 ** $QT_END_LICENSE$
 **
-****************************************************************************/
+****************************************************************************
+*/
 
 #include "qtlockedfile.h"
 
@@ -120,7 +148,7 @@ QtLockedFile::QtLockedFile(const QString &name)
 
   \sa QFile::open(), QFile::resize()
 */
-bool QtLockedFile::open(OpenMode mode)
+bool QtLockedFile::open(const OpenMode mode)
 {
     if (mode & QIODevice::Truncate) {
         qWarning("QtLockedFile::open(): Truncate mode not allowed.");