text: /*
   * Copyright (C) 2016 Apple Inc. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
   * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
   * THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #pragma once
  
  #include <type_traits>
  #include <wtf/StdLibExtras.h>
  
  // Based on http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0052r2.pdf
  
  namespace WTF {
  
  template<typename ExitFunction>
  class ScopeExit final {
  public:
      template<typename ExitFunctionParameter>
      explicit ScopeExit(ExitFunctionParameter&& exitFunction)
          : m_exitFunction(WTFMove(exitFunction))
      {
      }
  
      ScopeExit(ScopeExit&& other)
          : m_exitFunction(WTFMove(other.m_exitFunction))
          , m_executeOnDestruction(std::exchange(other.m_executeOnDestruction, false))
      {
      }
  
      ~ScopeExit()
      {
          if (m_executeOnDestruction)
              m_exitFunction();
      }
  
      void release()
      {
          m_executeOnDestruction = false;
      }
  
      ScopeExit(const ScopeExit&) = delete;
      ScopeExit& operator=(const ScopeExit&) = delete;
      ScopeExit& operator=(ScopeExit&&) = delete;
  
  private:
      ExitFunction m_exitFunction;
      bool m_executeOnDestruction { true };
  };
  
  
  template<typename ExitFunction> ScopeExit<ExitFunction> makeScopeExit(ExitFunction&&) WARN_UNUSED_RETURN;
  template<typename ExitFunction>
  ScopeExit<ExitFunction> makeScopeExit(ExitFunction&& exitFunction)
  {
      return ScopeExit<ExitFunction>(std::forward<ExitFunction>(exitFunction));
  }
  
  }
  
  using WTF::ScopeExit;
  using WTF::makeScopeExit;
  