qt-models/maplocationmodel: add new classes for map model based handling

The QML Map widget requires a QAbstractListModel based model to operate
with good performance. Technically gpslistmodel.cpp can be used for that
same purpose (e.g. has GPS coordinates), but the way it updates
may complicate the Map widget integration.

Thus, a new model is created - MapLocationModel, with items of type
MapLocation, for an attempt for a clean project structure on the C++ side.

For now it only handles latitude and longitude.

Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>

qt-models/maplocationmodel.cpp

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "maplocationmodel.h"
+
+MapLocation::MapLocation()
+{
+}
+
+MapLocation::MapLocation(qreal latitude, qreal longitude) :
+    m_latitude(latitude), m_longitude(longitude)
+{
+}
+
+QVariant MapLocation::getRole(int role) const
+{
+	switch (role) {
+	case Roles::RoleLatitude:
+		return m_latitude;
+	case Roles::RoleLongitude:
+		return m_longitude;
+	default:
+		return QVariant();
+	}
+}
+
+MapLocationModel::MapLocationModel(QObject *parent) : QAbstractListModel(parent)
+{
+	m_roles[MapLocation::Roles::RoleLatitude] = "latitude";
+	m_roles[MapLocation::Roles::RoleLongitude] = "longitude";
+}
+
+MapLocationModel::~MapLocationModel()
+{
+	qDeleteAll(m_mapLocations);
+}
+
+QVariant MapLocationModel::data( const QModelIndex & index, int role ) const
+{
+	if (index.row() < 0 || index.row() >= m_mapLocations.size())
+		return QVariant();
+
+	return m_mapLocations.at(index.row())->getRole(role);
+}
+
+QHash<int, QByteArray> MapLocationModel::roleNames() const
+{
+	return m_roles;
+}
+
+int MapLocationModel::rowCount(const QModelIndex &parent) const
+{
+	Q_UNUSED(parent);
+	return m_mapLocations.size();
+}
+
+int MapLocationModel::count()
+{
+	return m_mapLocations.size();
+}
+
+MapLocation *MapLocationModel::get(int row)
+{
+	if (row < 0 || row >= m_mapLocations.size())
+		return NULL;
+	return m_mapLocations.at(row);
+}