ui/views/focus/view_storage.h

   1 // Copyright (c) 2012 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 UI_VIEWS_FOCUS_VIEW_STORAGE_H_
   6 #define UI_VIEWS_FOCUS_VIEW_STORAGE_H_
   7
   8 #include <map>
   9 #include <vector>
  10
  11 #include "base/basictypes.h"
  12 #include "ui/views/views_export.h"
  13
  14 template <typename T> struct DefaultSingletonTraits;
  15
  16 // This class is a simple storage place for storing/retrieving views.  It is
  17 // used for example in the FocusManager to store/restore focused views when the
  18 // main window becomes active/inactive.
  19 // It automatically removes a view from the storage if the view is removed from
  20 // the tree hierarchy or when the view is destroyed, which ever comes first.
  21 //
  22 // To use it, you first need to create a view storage id that can then be used
  23 // to store/retrieve views.
  24
  25 namespace views {
  26 class View;
  27
  28 class VIEWS_EXPORT ViewStorage {
  29  public:
  30   // Returns the global ViewStorage instance.
  31   // It is guaranted to be non NULL.
  32   static ViewStorage* GetInstance();
  33
  34   // Returns a unique storage id that can be used to store/retrieve views.
  35   int CreateStorageID();
  36
  37   // Associates |view| with the specified |storage_id|.
  38   void StoreView(int storage_id, View* view);
  39
  40   // Returns the view associated with |storage_id| if any, NULL otherwise.
  41   View* RetrieveView(int storage_id);
  42
  43   // Removes the view associated with |storage_id| if any.
  44   void RemoveView(int storage_id);
  45
  46   // Notifies the ViewStorage that a view was removed from its parent somewhere.
  47   void ViewRemoved(View* removed);
  48
  49   size_t view_count() const { return view_to_ids_.size(); }
  50
  51  private:
  52   friend struct DefaultSingletonTraits<ViewStorage>;
  53
  54   ViewStorage();
  55   ~ViewStorage();
  56
  57   // Removes the view associated with |storage_id|. If |remove_all_ids| is true,
  58   // all other mapping pointing to the same view are removed as well.
  59   void EraseView(int storage_id, bool remove_all_ids);
  60
  61   // Next id for the view storage.
  62   int view_storage_next_id_;
  63
  64   // The association id to View used for the view storage.
  65   std::map<int, View*> id_to_view_;
  66
  67   // Association View to id, used to speed up view notification removal.
  68   std::map<View*, std::vector<int>*> view_to_ids_;
  69
  70   DISALLOW_COPY_AND_ASSIGN(ViewStorage);
  71 };
  72
  73 }  // namespace views
  74
  75 #endif  // UI_VIEWS_FOCUS_VIEW_STORAGE_H_