Move QObject-wrapping code into templates

Previously, this pattern was copy-pasted in a few places. This is
undesirable, so the code has been moved into templates.

Fixes #30

core/include/JellyfinQt/viewmodel/utils.h

@@ -0,0 +1,78 @@
+/*
+ * Sailfin: a Jellyfin client written using Qt
+ * Copyright (C) 2022 Chris Josten and the Sailfin Contributors.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+#ifndef JELLYFIN_VIEWMODEL_UTILS_H
+#define JELLYFIN_VIEWMODEL_UTILS_H
+
+#include <QObject>
+#include <QSharedPointer>
+#include <QVariant>
+
+/**
+ * \brief Wraps a data object in a QObject.
+ *
+ * This class is made for use in the ViewModel namespace, since many
+ * objects follow the pattern of having a constructor with a QSharedPointer<DTO::SomeItem>
+ * and a parent.
+ *
+ * The QObject wrapper class W must have a accessible constructor which takes only a QSharedPointer<D>
+ * as argument.
+ *
+ * \tparam W The QObject wrapper class
+ * \tparam D The DTO class
+ * \param data The data to wrap in a QObject
+ * \param parent The QObject to set as the parent of the newly created type.
+ */
+template<typename W, typename D>
+W *wrapQObject(D data, QObject *parent) {
+    return new W(QSharedPointer<D>::create(data), parent);
+}
+
+/**
+ * \brief Wraps a list of DTO items in a QVariantList of QObject's
+ * \see wrapQObject()
+ * \param begin The begin iterator of the list of DTO items
+ * \param end The end iterator of the list of DTO items
+ * \param parent The QObject to set as the parent of the QObjects in the newly created list.
+ */
+template<typename W, typename D, typename It>
+QVariantList wrapQVariantList(It begin, It end, QObject *parent) {
+    QVariantList result;
+    for (It it = begin; it != end; it++) {
+        result.append(QVariant::fromValue(wrapQObject<W, D>(*it, parent)));
+    }
+    return result;
+}
+
+/**
+ * \brief Wraps a list of DTO items in a QObjectList.
+ * \see wrapQObject()
+ * \param begin The begin iterator of the list of DTO items
+ * \param end The end iterator of the list of DTO items
+ * \param parent The QObject to set as the parent of the QObjects in the newly created list.
+ */
+template<typename W, typename D, typename It>
+QObjectList wrapQObjectList(It begin, It end, QObject *parent) {
+    QObjectList result;
+    for (It it = begin; it != end; it++) {
+        result.append(wrapQObject<W, D>(*it, parent));
+    }
+    return result;
+}
+
+#endif // JELLYFIN_VIEWMODEL_UTILS_H