[Aura] Implement views-based applist.

ui/base/models/list_model.h

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef UI_BASE_MODELS_LIST_MODEL_H_
+#define UI_BASE_MODELS_LIST_MODEL_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "base/observer_list.h"
+#include "base/memory/scoped_vector.h"
+#include "ui/base/models/list_model_observer.h"
+
+namespace ui {
+
+// A list model that manages a list of ItemType pointers. Items added to the
+// model are owned by the model. An item can be taken out of the model by
+// RemoveAt.
+template <class ItemType>
+class ListModel {
+ public:
+  typedef std::vector<ItemType*> Items;
+
+  ListModel() {}
+  virtual ~ListModel() {}
+
+  // Adds |item| to the model at given |index|.
+  virtual void AddAt(int index, ItemType* item) {
+    DCHECK(index >= 0 && index <= item_count());
+    items_->insert(items_.begin() + index, item);
+    NotifyItemsAdded(index, 1);
+  }
+
+  // Removes an item at given |index| from the model. Note the removed item
+  // is NOT deleted and it's up to the caller to delete it.
+  virtual ItemType* RemoveAt(int index) {
+    DCHECK(index >= 0 && index < item_count());
+    ItemType* item = items_[index];
+    items_->erase(items_.begin() + index);
+    NotifyItemsRemoved(index, 1);
+    return item;
+  }
+
+  // Removes all items from the model. This does NOT delete the items.
+  virtual void RemoveAll() {
+    int count = item_count();
+    items_->clear();
+    NotifyItemsRemoved(0, count);
+  }
+
+  // Removes an item at given |index| from the model and deletes it.
+  virtual void DeleteAt(int index) {
+    delete RemoveAt(index);
+  }
+
+  // Removes and deletes all items from the model.
+  virtual void DeleteAll() {
+    int count = item_count();
+    items_.reset();
+    NotifyItemsRemoved(0, count);
+  }
+
+  // Convenience function to append an item to the model.
+  void Add(ItemType* item) {
+    AddAt(item_count(), item);
+  }
+
+  void AddObserver(ListModelObserver* observer) {
+    observers_.AddObserver(observer);
+  }
+
+  void RemoveObserver(ListModelObserver* observer) {
+    observers_.RemoveObserver(observer);
+  }
+
+  void NotifyItemsAdded(int start, int count) {
+    FOR_EACH_OBSERVER(ListModelObserver,
+                      observers_,
+                      ListItemsAdded(start, count));
+  }
+
+  void NotifyItemsRemoved(int start, int count) {
+    FOR_EACH_OBSERVER(ListModelObserver,
+                      observers_,
+                      ListItemsRemoved(start, count));
+  }
+
+  void NotifyItemsChanged(int start, int count) {
+    FOR_EACH_OBSERVER(ListModelObserver,
+                      observers_,
+                      ListItemsChanged(start, count));
+  }
+
+  int item_count() const { return static_cast<int>(items_.size()); }
+  const Items& items() const { return items_.get(); }
+
+  const ItemType* item_at(int index) const {
+    DCHECK(index >= 0 && index < item_count());
+    return items_[index];
+  }
+  ItemType* item_at(int index) {
+    return const_cast<ItemType*>(
+        const_cast<const ListModel<ItemType>*>(this)->item_at(index));
+  }
+
+ private:
+  ScopedVector<ItemType> items_;
+  ObserverList<ListModelObserver> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(ListModel<ItemType>);
+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_MODELS_LIST_MODEL_H_