| // Copyright 2016 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef ASH_WINDOW_USER_DATA_H_ |
| #define ASH_WINDOW_USER_DATA_H_ |
| |
| #include<map> |
| #include<memory> |
| #include<utility> |
| |
| #include"ui/aura/window.h" |
| #include"ui/aura/window_observer.h" |
| |
| namespace ash{ |
| |
| // WindowUserData provides a way to associate an object with a Window and have |
| // that object destroyed when the window is destroyed, or when WindowUserData |
| // is destroyed (from aura::WindowObserver::OnWindowDestroying()). |
| // |
| // NOTE: WindowUserData does not make use of the Set/GetProperty API offered |
| // on aura::Window. This is done to avoid collisions in the case of multiple |
| // WindowUserDatas operating on the same Window. |
| template<typenameUserData> |
| classWindowUserData:public aura::WindowObserver{ |
| public: |
| WindowUserData(){} |
| |
| WindowUserData(constWindowUserData&)=delete; |
| WindowUserData&operator=(constWindowUserData&)=delete; |
| |
| ~WindowUserData()override{ clear();} |
| |
| void clear(){ |
| // Take care to destroy the data after removing from the map. |
| while(!window_to_data_.empty()){ |
| auto iter= window_to_data_.begin(); |
| iter->first->RemoveObserver(this); |
| std::unique_ptr<UserData> user_data= std::move(iter->second); |
| window_to_data_.erase(iter); |
| } |
| } |
| |
| // Sets the data associated with window. This destroys any existing data. |
| // |data| may be null. |
| voidSet(aura::Window* window, std::unique_ptr<UserData> data){ |
| if(!data){ |
| if(window_to_data_.erase(window)) |
| window->RemoveObserver(this); |
| return; |
| } |
| if(window_to_data_.count(window)==0u) |
| window->AddObserver(this); |
| window_to_data_[window]= std::move(data); |
| } |
| |
| // Returns the data associated with the window, or null if none set. The |
| // returned object is owned by WindowUserData. |
| UserData*Get(aura::Window* window){ |
| auto it= window_to_data_.find(window); |
| return it== window_to_data_.end()?nullptr: it->second.get(); |
| } |
| |
| // Returns the set of windows with data associated with them. |
| std::set<aura::Window*>GetWindows(){ |
| std::set<aura::Window*> windows; |
| for(auto& pair: window_to_data_) |
| windows.insert(pair.first); |
| return windows; |
| } |
| |
| private: |
| // aura::WindowObserver: |
| voidOnWindowDestroying(aura::Window* window)override{ |
| window->RemoveObserver(this); |
| window_to_data_.erase(window); |
| } |
| |
| std::map<aura::Window*, std::unique_ptr<UserData>> window_to_data_; |
| }; |
| |
| }// namespace ash |
| |
| #endif// ASH_WINDOW_USER_DATA_H_ |
