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/CMakeLists.txt

@@ -68,6 +68,7 @@ set(JellyfinQt_HEADERS
         include/JellyfinQt/viewmodel/userdata.h
         include/JellyfinQt/viewmodel/usermodel.h
         include/JellyfinQt/viewmodel/user.h
+        include/JellyfinQt/viewmodel/utils.h
         include/JellyfinQt/apiclient.h
         include/JellyfinQt/apimodel.h
         include/JellyfinQt/credentialmanager.h

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

core/src/viewmodel/item.cpp

@@ -22,6 +22,7 @@
 #include "JellyfinQt/loader/http/items.h"
 #include "JellyfinQt/loader/http/userlibrary.h"
 #include "JellyfinQt/viewmodel/userdata.h"
+#include "JellyfinQt/viewmodel/utils.h"
 
 namespace Jellyfin {
 namespace ViewModel {
@@ -81,11 +82,9 @@ void Item::updateMediaStreams() {
     qDebug() << m_audioStreams.size() << " audio streams, " << m_videoStreams.size() << " video streams, "
              << m_subtitleStreams.size() << " subtitle streams, " << m_allMediaStreams.size() << " streams total";
 
-    m_artistItems.clear();
     const QList<DTO::NameGuidPair> artists = m_data->artistItems();
-    for (auto it = artists.cbegin(); it != artists.cend(); it++) {
-        m_artistItems.append(new NameGuidPair(QSharedPointer<DTO::NameGuidPair>::create(*it), this));
-    }
+    qDeleteAll(m_artistItems);
+    m_artistItems = wrapQObjectList<NameGuidPair, DTO::NameGuidPair>(artists.cbegin(), artists.cend(), this);
 }
 
 void Item::setUserData(DTO::UserItemDataDto &newData) {

core/src/viewmodel/itemmodel.cpp

@@ -27,6 +27,7 @@
 #include "JellyfinQt/loader/http/tvshows.h"
 
 #include "JellyfinQt/viewmodel/userdata.h"
+#include "JellyfinQt/viewmodel/utils.h"
 
 #define JF_CASE(roleName) case roleName: \
     try { \
@@ -96,12 +97,8 @@ QVariant ItemModel::data(const QModelIndex &index, int role) const {
         return QVariant(item->runTimeTicks().value_or(0));
     JF_CASE(artists)
     case RoleNames::artistItems: {
-        QVariantList data;
         auto artists = item->artistItems();
-        for (auto it = artists.cbegin(); it != artists.cend(); it++) {
-            data.append(QVariant::fromValue(new NameGuidPair(QSharedPointer<DTO::NameGuidPair>::create(*it), const_cast<ItemModel *>(this))));
-        }
-        return data;
+        return wrapQVariantList<NameGuidPair, DTO::NameGuidPair>(artists.cbegin(), artists.cend(), const_cast<ItemModel *>(this));
     }
     case RoleNames::isFolder:
         return QVariant(item->isFolder().value_or(false));

core/src/viewmodel/playlist.cpp

@@ -19,6 +19,7 @@
 #include "JellyfinQt/viewmodel/playlist.h"
 
 #include "JellyfinQt/viewmodel/item.h"
+#include "JellyfinQt/viewmodel/utils.h"
 
 namespace Jellyfin {
 namespace ViewModel {
@@ -87,14 +88,8 @@ QVariant Playlist::data(const QModelIndex &index, int role) const {
     case RoleNames::artists:
         return QVariant(rowData->artists());
     case RoleNames::artistItems: {
-        QVariantList result;
-
-        auto items = rowData->artistItems();
-        for (auto it = items.cbegin(); it != items.cend(); it++) {
-            result.append(QVariant::fromValue(new NameGuidPair(QSharedPointer<DTO::NameGuidPair>::create(*it), const_cast<Playlist *>(this))));
-        }
-
-        return result;
+        auto artists = rowData->artistItems();
+        return wrapQVariantList<NameGuidPair, DTO::NameGuidPair>(artists.cbegin(), artists.cend(), const_cast<Playlist *>(this));
     }
     case RoleNames::runTimeTicks:
         return QVariant(rowData->runTimeTicks().value_or(-1));