gz/common/SingletonT.hh

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/*
 * Copyright (C) 2016 Open Source Robotics Foundation
 *
 * 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.
 *
*/
#ifndef GZ_COMMON_SINGLETONT_HH_
#define GZ_COMMON_SINGLETONT_HH_
 
namespace ignition
{
  namespace common
  {
    template <class T>
    class SingletonT
    {
      public: static T *Instance()
      {
        return &GetInstance();
      }
 
      protected: SingletonT() {}
 
      protected: virtual ~SingletonT() {}
 
      private: static T &GetInstance()
      {
        static T t;
        return static_cast<T &>(t);
      }
 
      private: static T &myself;
    };
 
    template <class T>
    T &SingletonT<T>::myself = SingletonT<T>::GetInstance();
  }
}
#endif