mlScopeGuard.h

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/*************************************************************************************
**
** Copyright 2013, MeVis Medical Solutions AG
**
** The user may use this file in accordance with the license agreement provided with
** the Software or, alternatively, in accordance with the terms contained in a
** written agreement between the user and MeVis Medical Solutions AG.
**
** For further information use the contact form at https://www.mevislab.de/contact
**
**************************************************************************************/
 
#pragma once
 
#include "mlTypeDefs.h"
 
#include <utility>
 
#define ML_UTILITIES_CONCATENATE_IMPL(s1,s2) s1##s2
#define ML_UTILITIES_CONCATENATE(s1,s2) ML_UTILITIES_CONCATENATE_IMPL(s1,s2)
 
// Some compiler does not support __COUNTER__ so there is an alternative
// implementation with __LINE__
#ifdef __COUNTER__
#define ML_UTILITIES_ANONYMOUS_VARIABLE(str)\
  ML_UTILITIES_CONCATENATE(str,__COUNTER__)
#else
#define ML_UTILITIES_ANONYMOUS_VARIABLE(str) \
  ML_UTILITIES_CONCATENATE(str,__LINE__)
#endif
 
ML_START_NAMESPACE
 
  namespace ScopeGuardDetail
  {
    template <class Functor>
    class ScopeGuard
    {
    public:
      explicit ScopeGuard(Functor fn)
        : _f(std::move(fn))
        , _active(true)
      {}
 
      ScopeGuard(ScopeGuard&& rhs)
        : _f(std::move(rhs._f))
        , _active(rhs._active)
      {
        rhs._active = false;
      }
 
      ~ScopeGuard()
      {
        if (_active)
        {
          _f();
        }
      }
 
      void dismiss()
      {
        _active = false;
      }
 
    private:
      Functor _f;
      bool _active;
 
      ScopeGuard() = delete;
      ScopeGuard(const ScopeGuard&) = delete;
      ScopeGuard& operator=(const ScopeGuard&) = delete;
    };
 
    enum class ScopeGuardOnExit {};
 
    template <class Functor>
    ScopeGuard<Functor> operator+(ScopeGuardOnExit, Functor&& fn)
    {
      return ScopeGuard<Functor>(std::forward<Functor>(fn));
    }
  }
 
ML_END_NAMESPACE
 
#define SCOPE_EXIT \
  auto ML_UTILITIES_ANONYMOUS_VARIABLE(SCOPE_EXIT_STATE) \
  = ::ML_NAMESPACE::ScopeGuardDetail::ScopeGuardOnExit() + [&]()
 
 
#define EXPLICIT_SCOPE_EXIT \
  ::ML_NAMESPACE::ScopeGuardDetail::ScopeGuardOnExit() + [&]()