strawberry-audio-player-win.../src/core/simpletreemodel.h

155 lines
4.3 KiB
C++

/*
* Strawberry Music Player
* This file was part of Clementine.
* Copyright 2010, David Sansome <me@davidsansome.com>
*
* Strawberry 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 3 of the License, or
* (at your option) any later version.
*
* Strawberry 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 Strawberry. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef SIMPLETREEMODEL_H
#define SIMPLETREEMODEL_H
#include "config.h"
#include <QObject>
#include <QAbstractItemModel>
#include <QModelIndex>
template <typename T>
class SimpleTreeModel : public QAbstractItemModel {
public:
explicit SimpleTreeModel(T *root = 0, QObject *parent = nullptr);
virtual ~SimpleTreeModel() {}
// QAbstractItemModel
int columnCount(const QModelIndex &parent) const;
QModelIndex index(int row, int, const QModelIndex &parent = QModelIndex()) const;
QModelIndex parent(const QModelIndex &index) const;
int rowCount(const QModelIndex &parent) const;
bool hasChildren(const QModelIndex &parent) const;
bool canFetchMore(const QModelIndex &parent) const;
void fetchMore(const QModelIndex &parent);
T *IndexToItem(const QModelIndex &index) const;
QModelIndex ItemToIndex(T *item) const;
// Called by items
void BeginInsert(T *parent, int start, int end = -1);
void EndInsert();
void BeginDelete(T *parent, int start, int end = -1);
void EndDelete();
void EmitDataChanged(T *item);
protected:
virtual void LazyPopulate(T *item) = 0;
protected:
T *root_;
};
template <typename T>
SimpleTreeModel<T>::SimpleTreeModel(T *root, QObject *parent)
: QAbstractItemModel(parent), root_(root) {}
template <typename T>
T *SimpleTreeModel<T>::IndexToItem(const QModelIndex &index) const {
if (!index.isValid()) return root_;
return reinterpret_cast<T*>(index.internalPointer());
}
template <typename T>
QModelIndex SimpleTreeModel<T>::ItemToIndex(T *item) const {
if (!item || !item->parent) return QModelIndex();
return createIndex(item->row, 0, item);
}
template <typename T>
int SimpleTreeModel<T>::columnCount(const QModelIndex&) const {
return 1;
}
template <typename T>
QModelIndex SimpleTreeModel<T>::index(int row, int, const QModelIndex &parent) const {
T *parent_item = IndexToItem(parent);
if (!parent_item || row < 0 || parent_item->children.count() <= row)
return QModelIndex();
return ItemToIndex(parent_item->children[row]);
}
template <typename T>
QModelIndex SimpleTreeModel<T>::parent(const QModelIndex &index) const {
return ItemToIndex(IndexToItem(index)->parent);
}
template <typename T>
int SimpleTreeModel<T>::rowCount(const QModelIndex &parent) const {
T *item = IndexToItem(parent);
return item->children.count();
}
template <typename T>
bool SimpleTreeModel<T>::hasChildren(const QModelIndex &parent) const {
T *item = IndexToItem(parent);
if (item->lazy_loaded)
return !item->children.isEmpty();
else
return true;
}
template <typename T>
bool SimpleTreeModel<T>::canFetchMore(const QModelIndex &parent) const {
T *item = IndexToItem(parent);
return !item->lazy_loaded;
}
template <typename T>
void SimpleTreeModel<T>::fetchMore(const QModelIndex &parent) {
T *item = IndexToItem(parent);
if (!item->lazy_loaded) {
LazyPopulate(item);
}
}
template <typename T>
void SimpleTreeModel<T>::BeginInsert(T *parent, int start, int end) {
if (end == -1) end = start;
beginInsertRows(ItemToIndex(parent), start, end);
}
template <typename T>
void SimpleTreeModel<T>::EndInsert() {
endInsertRows();
}
template <typename T>
void SimpleTreeModel<T>::BeginDelete(T *parent, int start, int end) {
if (end == -1) end = start;
beginRemoveRows(ItemToIndex(parent), start, end);
}
template <typename T>
void SimpleTreeModel<T>::EndDelete() {
endRemoveRows();
}
template <typename T>
void SimpleTreeModel<T>::EmitDataChanged(T *item) {
QModelIndex index(ItemToIndex(item));
emit dataChanged(index, index);
}
#endif // SIMPLETREEMODEL_H