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// Copyright (C) 2011 The Libphonenumber Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Author: Philippe Liard
#ifndef I18N_PHONENUMBERS_BASE_SINGLETON_H_
#define I18N_PHONENUMBERS_BASE_SINGLETON_H_
#if defined(I18N_PHONENUMBERS_USE_BOOST)
#include <boost/scoped_ptr.hpp>
#include <boost/thread/once.hpp>
#include <boost/utility.hpp>
namespace i18n {
namespace phonenumbers {
template <class T>
class Singleton : private boost::noncopyable {
public:
virtual ~Singleton() {}
static T* GetInstance() {
boost::call_once(Init, flag);
return instance.get();
}
private:
static void Init() {
instance.reset(new T());
}
static boost::scoped_ptr<T> instance;
static boost::once_flag flag;
};
template <class T> boost::scoped_ptr<T> Singleton<T>::instance;
template <class T> boost::once_flag Singleton<T>::flag = BOOST_ONCE_INIT;
#else // !I18N_PHONENUMBERS_USE_BOOST
#include "phonenumbers/base/logging.h"
#include "phonenumbers/base/thread_checker.h"
namespace i18n {
namespace phonenumbers {
// Note that this implementation is not thread-safe. For a thread-safe
// implementation, please compile with -DI18N_PHONENUMBERS_USE_BOOST.
template <class T>
class Singleton {
public:
Singleton() : thread_checker_() {}
virtual ~Singleton() {}
static T* GetInstance() {
static T* instance = NULL;
if (!instance) {
instance = new T();
}
DCHECK(instance->thread_checker_.CalledOnValidThread());
return instance;
}
private:
const ThreadChecker thread_checker_;
};
#endif // !I18N_PHONENUMBERS_USE_BOOST
} // namespace phonenumbers
} // namespace i18n
#endif // I18N_PHONENUMBERS_BASE_SINGLETON_H_