Store AppItems as pages in AppListModel.

ui/app_list/app_list_model.h

 // Copyright (c) 2012 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_APP_LIST_APP_LIST_MODEL_H_
 #define UI_APP_LIST_APP_LIST_MODEL_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/files/file_path.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "base/strings/string16.h"
 #include "ui/app_list/app_list_export.h"
 #include "ui/base/models/list_model.h"
 
 namespace app_list {
 
 class AppListItemModel;
 class AppListModelObserver;
 class SearchBoxModel;
 class SearchResult;
 
-// Master model of app list that consists of three sub models: Apps,
-// SearchBoxModel and SearchResults. The Apps sub model owns a list of
+// Master model of app list that consists of three sub models: AppItems,
+// SearchBoxModel and SearchResults. The AppItems sub model owns a list of
 // AppListItemModel and is displayed in the grid view. SearchBoxModel is
 // the model for SearchBoxView. SearchResults owns a list of SearchResult.
 class APP_LIST_EXPORT AppListModel {
  public:
   // A user of the app list.
   struct APP_LIST_EXPORT User {
     User();
     ~User();
 
     // Whether or not this user is the current user of the app list.
     bool active;
 
     // The name of this user.
     base::string16 name;
 
     // The email address of this user.
     base::string16 email;
 
     // The path to this user's profile directory.
     base::FilePath profile_path;
   };
 
   enum Status {
     STATUS_NORMAL,
     STATUS_SYNCING,  // Syncing apps or installing synced apps.
   };
 
-  typedef ui::ListModel<AppListItemModel> Apps;
+  typedef ui::ListModel<AppListItemModel> AppItems;
   typedef ui::ListModel<SearchResult> SearchResults;
   typedef std::vector<User> Users;
 
   AppListModel();
   ~AppListModel();
 
   void AddObserver(AppListModelObserver* observer);
   void RemoveObserver(AppListModelObserver* observer);
 
   void SetStatus(Status status);
   void SetUsers(const Users& profile_menu_items);
   void SetSignedIn(bool signed_in);
 
   // Find item matching |id|. NOTE: Requires a linear search.
   AppListItemModel* FindItem(const std::string& id);
 
-  // Adds |item| to |apps_|. Takes ownership of |item|. Uses item->SortOrder()
-  // to insert in the correct place. TODO(stevenjb): Use synced app list order
-  // instead of SortOrder when available: crbug.com/305024.
-  void AddItem(AppListItemModel* item);
+  // Returns the item at |page_idx| and |item_idx| or NULL.
+  AppListItemModel* GetItemAt(size_t page_idx, size_t item_idx);
 
-  // Finds |item| in |apps_| and deletes it.
+  // Adds |item| to a page. Takes ownership of |item|. Uses
+  // item->SortOrder() to insert in the correct page and position.
+  // Returns which page the item was added to.
+  // TODO(stevenjb): Use synced app list order instead of SortOrder.
+  // crbug.com/305024.
+  size_t AddItem(AppListItemModel* item);
+
+  // Similar to AddItem, but adds the item to a specific page. If the page is
+  // full, will return the index of the next page. |page_idx| must be
+  // <= the number of pages, i.e. at most one new page will be added.

[koz (OOO until 15th September), 2013/10/18 05:17:17]

What does it return when the page isn't full? -1?
When the page is full, it returns the index of the next page, I assume it
doesn't add the item then? Or does it keep moving along until it finds a page
that has capacity, adds it there and returns that page's index? Could you
clarify in the comment?

[stevenjb, 2013/10/18 22:14:26]

Clarified.

+  size_t AddItemToPage(AppListItemModel* item, size_t page_idx);
+
+  // Finds |item| in the model and deletes it.
   void DeleteItem(const std::string& id);
 
-  Apps* apps() { return apps_.get(); }
+  // Deletes item at |item_idx| from page |page_idx|.
+  void DeleteItemAt(size_t page_idx, size_t item_idx);
+
+  // Move item at |item_idx| in |page_idx| to |target_index|
+  // in |target_page_idx|.
+  void MoveItem(size_t page_idx, size_t item_idx,
+                size_t target_page_idx, size_t target_item_idx);
+
+  // Returns the number of apps per page.
+  static size_t GetNumAppsPerPage();
+
+  // Returns the number of app pages.
+  size_t GetNumAppPages() const;
+
+  // Returns a const reference to the items at page |page_idx| which must be
+  // less than GetAppPages().
+  const AppItems& GetAppItems(size_t page_idx) const;
+
   SearchBoxModel* search_box() { return search_box_.get(); }
   SearchResults* results() { return results_.get(); }
   Status status() const { return status_; }
   bool signed_in() const { return signed_in_; }
 
   const Users& users() const {
     return users_;
   }
 
- private:
-  scoped_ptr<Apps> apps_;
+private:
+  class ItemPage;
+
+  // Gets the list of items fpr |page_idx| from item_pages_ and checks ranges.
+  AppItems* app_items(size_t page_idx);
+
+  // Creates/removes a page of items.
+  void AddPage();
+  void RemovePage(size_t idx);
+
+  // Adds |item| to page |page_idx| at |item_idx| and handles overflow.
+  // Returns the page index for |item| which will differ from |page_idx| only
+  // if |item_idx| == GetNumAppsPerPage().
+  size_t AddItemToPageAtIndex(AppListItemModel* item,
+                              size_t page_idx, size_t item_idx);
+
+  // Sets the postion of |item| based on its new index.
+  void SetItemPosition(AppListItemModel* item,
+                       size_t page_idx, size_t item_idx);
+
+  ScopedVector<ItemPage> item_pages_;
 
   scoped_ptr<SearchBoxModel> search_box_;
   scoped_ptr<SearchResults> results_;
 
   Users users_;
 
   bool signed_in_;
   Status status_;
   ObserverList<AppListModelObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListModel);
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_APP_LIST_MODEL_H_