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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef ASH_SHELF_SHELF_MODEL_H_
      6 #define ASH_SHELF_SHELF_MODEL_H_
      7 
      8 #include "ash/ash_export.h"
      9 #include "ash/shelf/shelf_item_types.h"
     10 #include "base/basictypes.h"
     11 #include "base/observer_list.h"
     12 
     13 namespace ash {
     14 
     15 class ShelfModelObserver;
     16 
     17 // Model used by ShelfView.
     18 class ASH_EXPORT ShelfModel {
     19  public:
     20   enum Status {
     21     STATUS_NORMAL,
     22     // A status that indicates apps are syncing/loading.
     23     STATUS_LOADING,
     24   };
     25 
     26   ShelfModel();
     27   ~ShelfModel();
     28 
     29   // Adds a new item to the model. Returns the resulting index.
     30   int Add(const ShelfItem& item);
     31 
     32   // Adds the item. |index| is the requested insertion index, which may be
     33   // modified to meet type-based ordering. Returns the actual insertion index.
     34   int AddAt(int index, const ShelfItem& item);
     35 
     36   // Removes the item at |index|.
     37   void RemoveItemAt(int index);
     38 
     39   // Moves the item at |index| to |target_index|. |target_index| is in terms
     40   // of the model *after* the item at |index| is removed.
     41   void Move(int index, int target_index);
     42 
     43   // Resets the item at the specified index. The item maintains its existing
     44   // id and type.
     45   void Set(int index, const ShelfItem& item);
     46 
     47   // Returns the index of the item by id.
     48   int ItemIndexByID(ShelfID id) const;
     49 
     50   // Returns the |index| of the item matching |type| in |items_|.
     51   // Returns -1 if the matching item is not found.
     52   // Note: Requires a linear search.
     53   int GetItemIndexForType(ShelfItemType type);
     54 
     55   // Returns the index of the first running application or the index where the
     56   // first running application would go if there are no running (non pinned)
     57   // applications yet.
     58   int FirstRunningAppIndex() const;
     59 
     60   // Returns the index of the first panel or the index where the first panel
     61   // would go if there are no panels.
     62   int FirstPanelIndex() const;
     63 
     64   // Returns the id assigned to the next item added.
     65   ShelfID next_id() const { return next_id_; }
     66 
     67   // Returns a reserved id which will not be used by the |ShelfModel|.
     68   ShelfID reserve_external_id() { return next_id_++; }
     69 
     70   // Returns an iterator into items() for the item with the specified id, or
     71   // items().end() if there is no item with the specified id.
     72   ShelfItems::const_iterator ItemByID(ShelfID id) const;
     73 
     74   const ShelfItems& items() const { return items_; }
     75   int item_count() const { return static_cast<int>(items_.size()); }
     76 
     77   void SetStatus(Status status);
     78   Status status() const { return status_; }
     79 
     80   void AddObserver(ShelfModelObserver* observer);
     81   void RemoveObserver(ShelfModelObserver* observer);
     82 
     83  private:
     84   // Makes sure |index| is in line with the type-based order of items. If that
     85   // is not the case, adjusts index by shifting it to the valid range and
     86   // returns the new value.
     87   int ValidateInsertionIndex(ShelfItemType type, int index) const;
     88 
     89   // ID assigned to the next item.
     90   ShelfID next_id_;
     91 
     92   ShelfItems items_;
     93   Status status_;
     94   ObserverList<ShelfModelObserver> observers_;
     95 
     96   DISALLOW_COPY_AND_ASSIGN(ShelfModel);
     97 };
     98 
     99 }  // namespace ash
    100 
    101 #endif  // ASH_SHELF_SHELF_MODEL_H_
    102