components/webui_generator/view.h

   1 // Copyright 2015 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 CHROME_BROWSER_UI_WEBUI_WUG_VIEW_H_
   6 #define CHROME_BROWSER_UI_WEBUI_WUG_VIEW_H_
   7
   8 #include "base/containers/scoped_ptr_hash_map.h"
   9 #include "base/macros.h"
  10 #include "base/memory/weak_ptr.h"
  11 #include "components/webui_generator/export.h"
  12
  13 namespace base {
  14 class DictionaryValue;
  15 }
  16
  17 namespace webui_generator {
  18
  19 class ViewModel;
  20
  21 /**
  22  * Base block of Web UI (in terms of Web UI Generator). Every View instance is
  23  * associated with single ViewModel instance which provides a context for the
  24  * view. Views are hierarchical. Every child of view has an unique id.
  25  */
  26 class WUG_EXPORT View {
  27  public:
  28   explicit View(const std::string& id);
  29   virtual ~View();
  30
  31   // Should be called before using the view. This method creates children (using
  32   // CreateAndAddChildren() method) and a view-model (using CreateViewModel()
  33   // method). Then it recursively calls Init() for the children. When
  34   // all the children and the view-model are ready, OnReady() method is called.
  35   // Overridden methods should call the base implementation.
  36   virtual void Init();
  37
  38   // Root view is a view without parent.
  39   // Root view should have id equal to "WUG_ROOT".
  40   bool IsRootView() const;
  41
  42   ViewModel* GetViewModel() const;
  43
  44   // Called by view-model when it is ready.
  45   void OnViewModelReady();
  46
  47   const std::string& id() const { return id_; }
  48
  49   // Every view has an unique path in a view hierarchy which is:
  50   //  a) |id| for the root view;
  51   //  b) concatenation of parent's path, $-sign and |id| for not-root views.
  52   const std::string& path() const { return path_; }
  53
  54   // Returns a child with a given |id|. Returns |nullptr| if such child doesn't
  55   // exist.
  56   View* GetChild(const std::string& id) const;
  57
  58   // Called by view-model when it changes the context.
  59   virtual void OnContextChanged(const base::DictionaryValue& diff) = 0;
  60
  61  protected:
  62   // Called when view is ready, which means view-model and all children are
  63   // ready. Overridden methods should call the base implementation.
  64   virtual void OnReady();
  65
  66   // Forwards context changes stored in |diff| to view-model.
  67   void UpdateContext(const base::DictionaryValue& diff);
  68
  69   // Forwards |event| to view-model.
  70   void HandleEvent(const std::string& event);
  71
  72   bool ready() const { return ready_; }
  73
  74   base::ScopedPtrHashMap<std::string, scoped_ptr<View>>& children() {
  75     return children_;
  76   }
  77
  78   // Adds |child| to the list of children of |this|. Can be called only from
  79   // CreateAndAddChildren() override.
  80   void AddChild(View* child);
  81
  82   virtual std::string GetType() = 0;
  83
  84   // Implementation should create an instance of view-model for this view.
  85   virtual ViewModel* CreateViewModel() = 0;
  86
  87   // Implementation should create and add children to |this| view. This method
  88   // is an only place where it is allowed to add children.
  89   virtual void CreateAndAddChildren() = 0;
  90
  91  private:
  92   // Called by |child| view, when it is ready.
  93   void OnChildReady(View* child);
  94
  95   // Called when all the children created by CreatedAndAddChildren() are ready.
  96   void OnChildrenReady();
  97
  98   void set_parent(View* parent) { parent_ = parent; }
  99
 100   View* parent_;
 101   std::string id_;
 102   std::string path_;
 103
 104   // Number of child views that are ready.
 105   int ready_children_;
 106
 107   bool view_model_ready_;
 108   bool ready_;
 109   base::ScopedPtrHashMap<std::string, scoped_ptr<View>> children_;
 110   scoped_ptr<ViewModel> view_model_;
 111   base::WeakPtrFactory<View> weak_factory_;
 112
 113   DISALLOW_COPY_AND_ASSIGN(View);
 114 };
 115
 116 }  // namespace webui_generator
 117
 118 #endif  // CHROME_BROWSER_UI_WEBUI_WUG_VIEW_H_