15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_USER_DATA_H_ 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_USER_DATA_H_ 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/logging.h" 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/supports_user_data.h" 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "content/public/browser/web_contents.h" 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace content { 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// A base class for classes attached to, and scoped to, the lifetime of a 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// WebContents. For example: 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// --- in foo_tab_helper.h --- 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// class FooTabHelper : public content::WebContentsUserData<FooTabHelper> { 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// public: 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// virtual ~FooTabHelper(); 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// // ... more public stuff here ... 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// private: 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// explicit FooTabHelper(content::WebContents* contents); 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// friend class content::WebContentsUserData<FooTabHelper>; 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// // ... more private stuff here ... 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// } 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// --- in foo_tab_helper.cc --- 282a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// DEFINE_WEB_CONTENTS_USER_DATA_KEY(FooTabHelper); 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <typename T> 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class WebContentsUserData : public base::SupportsUserData::Data { 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Creates an object of type T, and attaches it to the specified WebContents. 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If an instance is already attached, does nothing. 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static void CreateForWebContents(WebContents* contents) { 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(contents); 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!FromWebContents(contents)) 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) contents->SetUserData(UserDataKey(), new T(contents)); 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Retrieves the instance of type T that was attached to the specified 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // WebContents (via CreateForWebContents above) and returns it. If no instance 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // of the type was attached, returns NULL. 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static T* FromWebContents(WebContents* contents) { 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(contents); 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return static_cast<T*>(contents->GetUserData(UserDataKey())); 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static const T* FromWebContents(const WebContents* contents) { 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DCHECK(contents); 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return static_cast<const T*>(contents->GetUserData(UserDataKey())); 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) protected: 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static inline void* UserDataKey() { 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return &kLocatorKey; 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The user data key. 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static int kLocatorKey; 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The macro to define the locator key. This key must be defined in the .cc file 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// of the tab helper otherwise different instances for different template types 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// will be collapsed by the Visual Studio linker. 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The "= 0" is surprising, but is required to effect a definition rather than 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// a declaration. Without it, this would be merely a declaration of a template 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// specialization. (C++98: 14.7.3.15; C++11: 14.7.3.13) 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define DEFINE_WEB_CONTENTS_USER_DATA_KEY(TYPE) \ 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template<> \ 732a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)int content::WebContentsUserData<TYPE>::kLocatorKey = 0 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace content 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_USER_DATA_H_ 78