Initial commit.

src/core/simpletreemodel.h

@@ -0,0 +1,154 @@
+/*
+ * 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 <QAbstractItemModel>
+
+class 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