Initial implementation of WebUI generator (WUG) toolkit.

components/webui_generator/view.h

+// Copyright 2015 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 CHROME_BROWSER_UI_WEBUI_WUG_VIEW_H_
+#define CHROME_BROWSER_UI_WEBUI_WUG_VIEW_H_
+
+#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "components/webui_generator/export.h"
+
+namespace base {
+class DictionaryValue;
+}
+
+namespace webui_generator {
+
+class ViewModel;
+
+/**
+ * Base block of Web UI (in terms of Web UI Generator). Every View instance is
+ * associated with single ViewModel instance which provides a context for the
+ * view. Views are hierarchical. Every child of view has an unique id.
+ */
+class WUG_EXPORT View {
+ public:
+  explicit View(const std::string& id);
+  virtual ~View();
+
+  // Should be called before using the view. This method creates children (using
+  // CreateAndAddChildren() method) and a view-model (using CreateViewModel()
+  // method). Then it recursively calls Init() for the children. When
+  // all the children and the view-model are ready, OnReady() method is called.
+  // Overridden methods should call the base implementation.
+  virtual void Init();
+
+  // Root view is a view without parent.
+  // Root view should have id equal to "WUG_ROOT".
+  bool IsRootView() const;
+
+  ViewModel* GetViewModel() const;
+
+  // Called by view-model when it is ready.
+  void OnViewModelReady();
+
+  const std::string& id() const { return id_; }
+
+  // Every view has an unique path in a view hierarchy which is:
+  //  a) |id| for the root view;
+  //  b) concatenation of parent's path, $-sign and |id| for not-root views.
+  const std::string& path() const { return path_; }
+
+  // Returns a child with a given |id|. Returns |nullptr| if such child doesn't
+  // exist.
+  View* GetChild(const std::string& id) const;
+
+  // Called by view-model when it changes the context.
+  virtual void OnContextChanged(const base::DictionaryValue& diff) = 0;
+
+ protected:
+  // Called when view is ready, which means view-model and all children are
+  // ready. Overridden methods should call the base implementation.
+  virtual void OnReady();
+
+  // Forwards context changes stored in |diff| to view-model.
+  void UpdateContext(const base::DictionaryValue& diff);
+
+  // Forwards |event| to view-model.
+  void HandleEvent(const std::string& event);
+
+  bool ready() const { return ready_; }
+
+  base::ScopedPtrHashMap<std::string, View>& children() { return children_; }
+
+  // Adds |child| to the list of children of |this|. Can be called only from
+  // CreateAndAddChildren() override.
+  void AddChild(View* child);
+
+  virtual std::string GetType() = 0;
+
+  // Implementation should create an instance of view-model for this view.
+  virtual ViewModel* CreateViewModel() = 0;
+
+  // Implementation should create and add children to |this| view. This method
+  // is an only place where it is allowed to add children.
+  virtual void CreateAndAddChildren() = 0;
+
+ private:
+  // Called by |child| view, when it is ready.
+  void OnChildReady(View* child);
+
+  // Called when all the children created by CreatedAndAddChildren() are ready.
+  void OnChildrenReady();
+
+  void set_parent(View* parent) { parent_ = parent; }
+
+  View* parent_;
+  std::string id_;
+  std::string path_;
+
+  // Number of child views that are ready.
+  int ready_children_;
+
+  bool view_model_ready_;
+  bool ready_;
+  base::ScopedPtrHashMap<std::string, View> children_;
+  scoped_ptr<ViewModel> view_model_;
+  base::WeakPtrFactory<View> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(View);
+};
+
+}  // namespace webui_generator
+
+#endif  // CHROME_BROWSER_UI_WEBUI_WUG_VIEW_H_