1// Copyright 2013 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// Helper class used to find the RenderFrameObservers for a given RenderFrame. 6// 7// Example usage: 8// 9// class MyRFO : public RenderFrameObserver, 10// public RenderFrameObserverTracker<MyRFO> { 11// ... 12// }; 13// 14// MyRFO::MyRFO(RenderFrame* render_frame) 15// : RenderFrameObserver(render_frame), 16// RenderFrameObserverTracker<MyRFO>(render_frame) { 17// ... 18// } 19// 20// void SomeFunction(RenderFrame* rf) { 21// MyRFO* my_rfo = new MyRFO(rf); 22// MyRFO* my_rfo_tracked = MyRFO::Get(rf); 23// // my_rfo == my_rfo_tracked 24// } 25 26#ifndef CONTENT_PUBLIC_RENDERER_RENDER_FRAME_OBSERVER_TRACKER_H_ 27#define CONTENT_PUBLIC_RENDERER_RENDER_FRAME_OBSERVER_TRACKER_H_ 28 29#include <map> 30 31#include "base/lazy_instance.h" 32 33namespace content { 34 35class RenderFrame; 36 37template <class T> 38class RenderFrameObserverTracker { 39 public: 40 static T* Get(const RenderFrame* render_frame) { 41 return render_frame_map_.Get()[render_frame]; 42 } 43 44 explicit RenderFrameObserverTracker(const RenderFrame* render_frame) 45 : render_frame_(render_frame) { 46 render_frame_map_.Get()[render_frame] = static_cast<T*>(this); 47 } 48 ~RenderFrameObserverTracker() { 49 render_frame_map_.Get().erase(render_frame_); 50 } 51 52 private: 53 const RenderFrame* render_frame_; 54 55 static base::LazyInstance<std::map<const RenderFrame*, T*> > 56 render_frame_map_; 57 58 DISALLOW_COPY_AND_ASSIGN(RenderFrameObserverTracker<T>); 59}; 60 61template <class T> 62base::LazyInstance<std::map<const RenderFrame*, T*> > 63 RenderFrameObserverTracker<T>::render_frame_map_ = 64 LAZY_INSTANCE_INITIALIZER; 65 66} // namespace content 67 68#endif // CONTENT_PUBLIC_RENDERER_RENDER_FRAME_OBSERVER_TRACKER_H_ 69