| // Copyright 2016 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 ASH_WINDOW_USER_DATA_H_ |
| #define ASH_WINDOW_USER_DATA_H_ |
| |
| #include <map> |
| #include <memory> |
| #include <utility> |
| |
| #include "base/macros.h" |
| #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 <typename UserData> |
| class WindowUserData : public aura::WindowObserver { |
| public: |
| WindowUserData() {} |
| |
| ~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. |
| void Set(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: |
| void OnWindowDestroying(aura::Window* window) override { |
| window->RemoveObserver(this); |
| window_to_data_.erase(window); |
| } |
| |
| std::map<aura::Window*, std::unique_ptr<UserData>> window_to_data_; |
| |
| DISALLOW_COPY_AND_ASSIGN(WindowUserData); |
| }; |
| |
| } // namespace ash |
| |
| #endif // ASH_WINDOW_USER_DATA_H_ |