11e9bf3e0803691d0a228da41fc608347b6db4340Torne (Richard Coles)// Copyright 2013 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)// A helper class that assists preferences in firing notifications when lists 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// or dictionaries are changed. 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 81e9bf3e0803691d0a228da41fc608347b6db4340Torne (Richard Coles)#ifndef BASE_PREFS_SCOPED_USER_PREF_UPDATE_H_ 91e9bf3e0803691d0a228da41fc608347b6db4340Torne (Richard Coles)#define BASE_PREFS_SCOPED_USER_PREF_UPDATE_H_ 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <string> 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/basictypes.h" 141e9bf3e0803691d0a228da41fc608347b6db4340Torne (Richard Coles)#include "base/prefs/base_prefs_export.h" 152a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)#include "base/prefs/pref_service.h" 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/threading/non_thread_safe.h" 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/values.h" 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class PrefService; 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace base { 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class DictionaryValue; 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class ListValue; 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace subtle { 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Base class for ScopedUserPrefUpdateTemplate that contains the parts 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// that do not depend on ScopedUserPrefUpdateTemplate's template parameter. 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// We need this base class mostly for making it a friend of PrefService 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// and getting access to PrefService::GetMutableUserPref and 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// PrefService::ReportUserPrefChanged. 341e9bf3e0803691d0a228da41fc608347b6db4340Torne (Richard Coles)class BASE_PREFS_EXPORT ScopedUserPrefUpdateBase : public base::NonThreadSafe { 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) protected: 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ScopedUserPrefUpdateBase(PrefService* service, const char* path); 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Calls Notify(). 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ~ScopedUserPrefUpdateBase(); 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Sets |value_| to |service_|->GetMutableUserPref and returns it. 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Value* GetValueOfType(base::Value::Type type); 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If |value_| is not null, triggers a notification of PrefObservers and 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // resets |value_|. 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) void Notify(); 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Weak pointer. 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) PrefService* service_; 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Path of the preference being updated. 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) std::string path_; 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Cache of value from user pref store (set between Get() and Notify() calls). 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Value* value_; 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(ScopedUserPrefUpdateBase); 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace subtle 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Class to support modifications to DictionaryValues and ListValues while 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// guaranteeing that PrefObservers are notified of changed values. 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This class may only be used on the UI thread as it requires access to the 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// PrefService. 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <typename T, base::Value::Type type_enum_value> 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class ScopedUserPrefUpdate : public subtle::ScopedUserPrefUpdateBase { 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) public: 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ScopedUserPrefUpdate(PrefService* service, const char* path) 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) : ScopedUserPrefUpdateBase(service, path) {} 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Triggers an update notification if Get() was called. 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual ~ScopedUserPrefUpdate() {} 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Returns a mutable |T| instance that 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // - is already in the user pref store, or 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // - is (silently) created and written to the user pref store if none existed 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // before. 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Calling Get() implies that an update notification is necessary at 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // destruction time. 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The ownership of the return value remains with the user pref store. 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Virtual so it can be overriden in subclasses that transform the value 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // before returning it (for example to return a subelement of a dictionary). 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) virtual T* Get() { 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return static_cast<T*>(GetValueOfType(type_enum_value)); 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) T& operator*() { 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return *Get(); 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) T* operator->() { 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return Get(); 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) private: 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(ScopedUserPrefUpdate); 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 102eb525c5499e34cc9c4b825d6d9e75bb07cc06aceBen Murdochtypedef ScopedUserPrefUpdate<base::DictionaryValue, 103eb525c5499e34cc9c4b825d6d9e75bb07cc06aceBen Murdoch base::Value::TYPE_DICTIONARY> 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) DictionaryPrefUpdate; 105eb525c5499e34cc9c4b825d6d9e75bb07cc06aceBen Murdochtypedef ScopedUserPrefUpdate<base::ListValue, base::Value::TYPE_LIST> 106eb525c5499e34cc9c4b825d6d9e75bb07cc06aceBen Murdoch ListPrefUpdate; 1075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1081e9bf3e0803691d0a228da41fc608347b6db4340Torne (Richard Coles)#endif // BASE_PREFS_SCOPED_USER_PREF_UPDATE_H_ 109