61 lines
2.3 KiB
C
61 lines
2.3 KiB
C
|
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
|
||
|
|
// Use of this source code is governed by a BSD-style license that can be
|
||
|
|
// found in the LICENSE file.
|
||
|
|
|
||
|
|
// Support for using the Singleton<T> pattern with Objective-C objects. A
|
||
|
|
// SingletonObjC is the same as a Singleton, except the default traits are
|
||
|
|
// appropriate for Objective-C objects. A typical Objective-C object of type
|
||
|
|
// NSExampleType can be maintained as a singleton and accessed with:
|
||
|
|
//
|
||
|
|
// NSExampleType* exampleSingleton = SingletonObjC<NSExampleType>::get();
|
||
|
|
//
|
||
|
|
// The first time this is used, it will create exampleSingleton as the result
|
||
|
|
// of [[NSExampleType alloc] init]. Subsequent calls will return the same
|
||
|
|
// NSExampleType* object. The object will be released by calling
|
||
|
|
// -[NSExampleType release] when Singleton's atexit routines run
|
||
|
|
// (see singleton.h).
|
||
|
|
//
|
||
|
|
// For Objective-C objects initialized through means other than the
|
||
|
|
// no-parameter -init selector, DefaultSingletonObjCTraits may be extended
|
||
|
|
// as needed:
|
||
|
|
//
|
||
|
|
// struct FooSingletonTraits : public DefaultSingletonObjCTraits<Foo> {
|
||
|
|
// static Foo* New() {
|
||
|
|
// return [[Foo alloc] initWithName:@"selecty"];
|
||
|
|
// }
|
||
|
|
// };
|
||
|
|
// ...
|
||
|
|
// Foo* widgetSingleton = SingletonObjC<Foo, FooSingletonTraits>::get();
|
||
|
|
|
||
|
|
#ifndef BASE_MEMORY_SINGLETON_OBJC_H_
|
||
|
|
#define BASE_MEMORY_SINGLETON_OBJC_H_
|
||
|
|
|
||
|
|
#import <Foundation/Foundation.h>
|
||
|
|
#include "base/memory/singleton.h"
|
||
|
|
|
||
|
|
// Singleton traits usable to manage traditional Objective-C objects, which
|
||
|
|
// are instantiated by sending |alloc| and |init| messages, and are deallocated
|
||
|
|
// in a memory-managed environment when their retain counts drop to 0 by
|
||
|
|
// sending |release| messages.
|
||
|
|
template<typename Type>
|
||
|
|
struct DefaultSingletonObjCTraits : public DefaultSingletonTraits<Type> {
|
||
|
|
static Type* New() {
|
||
|
|
return [[Type alloc] init];
|
||
|
|
}
|
||
|
|
|
||
|
|
static void Delete(Type* object) {
|
||
|
|
[object release];
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
// Exactly like Singleton, but without the DefaultSingletonObjCTraits as the
|
||
|
|
// default trait class. This makes it straightforward for Objective-C++ code
|
||
|
|
// to hold Objective-C objects as singletons.
|
||
|
|
template<typename Type,
|
||
|
|
typename Traits = DefaultSingletonObjCTraits<Type>,
|
||
|
|
typename DifferentiatingType = Type>
|
||
|
|
class SingletonObjC : public Singleton<Type, Traits, DifferentiatingType> {
|
||
|
|
};
|
||
|
|
|
||
|
|
#endif // BASE_MEMORY_SINGLETON_OBJC_H_
|