1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/base/singleton_objc.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,60 @@
1.4 +// Copyright (c) 2008 The Chromium Authors. All rights reserved.
1.5 +// Use of this source code is governed by a BSD-style license that can be
1.6 +// found in the LICENSE file.
1.7 +
1.8 +// Support for using the Singleton<T> pattern with Objective-C objects. A
1.9 +// SingletonObjC is the same as a Singleton, except the default traits are
1.10 +// appropriate for Objective-C objects. A typical Objective-C object of type
1.11 +// NSExampleType can be maintained as a singleton and accessed with:
1.12 +//
1.13 +// NSExampleType* exampleSingleton = SingletonObjC<NSExampleType>::get();
1.14 +//
1.15 +// The first time this is used, it will create exampleSingleton as the result
1.16 +// of [[NSExampleType alloc] init]. Subsequent calls will return the same
1.17 +// NSExampleType* object. The object will be released by calling
1.18 +// -[NSExampleType release] when Singleton's atexit routines run
1.19 +// (see singleton.h).
1.20 +//
1.21 +// For Objective-C objects initialized through means other than the
1.22 +// no-parameter -init selector, DefaultSingletonObjCTraits may be extended
1.23 +// as needed:
1.24 +//
1.25 +// struct FooSingletonTraits : public DefaultSingletonObjCTraits<Foo> {
1.26 +// static Foo* New() {
1.27 +// return [[Foo alloc] initWithName:@"selecty"];
1.28 +// }
1.29 +// }
1.30 +// ...
1.31 +// Foo* widgetSingleton = SingletonObjC<Foo, FooSingletonTraits>::get();
1.32 +
1.33 +#ifndef BASE_SINGLETON_OBJC_H_
1.34 +#define BASE_SINGLETON_OBJC_H_
1.35 +
1.36 +#import <Foundation/Foundation.h>
1.37 +#include "base/singleton.h"
1.38 +
1.39 +// Singleton traits usable to manage traditional Objective-C objects, which
1.40 +// are instantiated by sending |alloc| and |init| messages, and are deallocated
1.41 +// in a memory-managed environment when their retain counts drop to 0 by
1.42 +// sending |release| messages.
1.43 +template<typename Type>
1.44 +struct DefaultSingletonObjCTraits : public DefaultSingletonTraits<Type> {
1.45 + static Type* New() {
1.46 + return [[Type alloc] init];
1.47 + }
1.48 +
1.49 + static void Delete(Type* object) {
1.50 + [object release];
1.51 + }
1.52 +};
1.53 +
1.54 +// Exactly like Singleton, but without the DefaultSingletonObjCTraits as the
1.55 +// default trait class. This makes it straightforward for Objective-C++ code
1.56 +// to hold Objective-C objects as singletons.
1.57 +template<typename Type,
1.58 + typename Traits = DefaultSingletonObjCTraits<Type>,
1.59 + typename DifferentiatingType = Type>
1.60 +class SingletonObjC : public Singleton<Type, Traits, DifferentiatingType> {
1.61 +};
1.62 +
1.63 +#endif // BASE_SINGLETON_OBJC_H_
