15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2011 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)// Support for using the Singleton<T> pattern with Objective-C objects. A 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// SingletonObjC is the same as a Singleton, except the default traits are 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// appropriate for Objective-C objects. A typical Objective-C object of type 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// NSExampleType can be maintained as a singleton and accessed with: 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// NSExampleType* exampleSingleton = SingletonObjC<NSExampleType>::get(); 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The first time this is used, it will create exampleSingleton as the result 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// of [[NSExampleType alloc] init]. Subsequent calls will return the same 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// NSExampleType* object. The object will be released by calling 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// -[NSExampleType release] when Singleton's atexit routines run 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// (see singleton.h). 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// For Objective-C objects initialized through means other than the 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// no-parameter -init selector, DefaultSingletonObjCTraits may be extended 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// as needed: 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// struct FooSingletonTraits : public DefaultSingletonObjCTraits<Foo> { 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// static Foo* New() { 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// return [[Foo alloc] initWithName:@"selecty"]; 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// } 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// }; 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// ... 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Foo* widgetSingleton = SingletonObjC<Foo, FooSingletonTraits>::get(); 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef BASE_MEMORY_SINGLETON_OBJC_H_ 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_MEMORY_SINGLETON_OBJC_H_ 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#import <Foundation/Foundation.h> 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/memory/singleton.h" 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Singleton traits usable to manage traditional Objective-C objects, which 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// are instantiated by sending |alloc| and |init| messages, and are deallocated 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// in a memory-managed environment when their retain counts drop to 0 by 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// sending |release| messages. 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template<typename Type> 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)struct DefaultSingletonObjCTraits : public DefaultSingletonTraits<Type> { 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static Type* New() { 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return [[Type alloc] init]; 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) static void Delete(Type* object) { 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) [object release]; 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Exactly like Singleton, but without the DefaultSingletonObjCTraits as the 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// default trait class. This makes it straightforward for Objective-C++ code 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// to hold Objective-C objects as singletons. 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template<typename Type, 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typename Traits = DefaultSingletonObjCTraits<Type>, 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) typename DifferentiatingType = Type> 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)class SingletonObjC : public Singleton<Type, Traits, DifferentiatingType> { 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)}; 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_MEMORY_SINGLETON_OBJC_H_ 61