Clementine-audio-player-Mac.../src/simpletreemodel.h

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#ifndef SIMPLETREEMODEL_H
#define SIMPLETREEMODEL_H
#include <QAbstractItemModel>
class QModelIndex;
template <typename T>
class SimpleTreeModel : public QAbstractItemModel {
public:
SimpleTreeModel(T* root = 0, QObject* parent = 0);
virtual ~SimpleTreeModel() {}
// QAbstractItemModel
int columnCount(const QModelIndex& parent) const;
QModelIndex index(int row, int, const QModelIndex& parent) const;
QModelIndex parent(const QModelIndex& index) const;
int rowCount(const QModelIndex& parent) const;
bool hasChildren(const QModelIndex& parent) const;
T* IndexToItem(const QModelIndex& index) const;
QModelIndex ItemToIndex(T* item) const;
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// 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();
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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 || 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);
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if (!item->lazy_loaded)
const_cast<SimpleTreeModel<T>*>(this)->LazyPopulate(item); // Ahem
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;
}
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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();
}
#endif // SIMPLETREEMODEL_H