text: ﻿
  #ifndef __base_auto_reset_h__
  #define __base_auto_reset_h__
  
  #pragma once
  
  // AutoReset<> is useful for setting a variable to a new value only within a
  // particular scope. An AutoReset<> object resets a variable to its original
  // value upon destruction, making it an alternative to writing "var = false;"
  // or "var = old_val;" at all of a block's exit points.
  //
  // This should be obvious, but note that an AutoReset<> instance should have a
  // shorter lifetime than its scoped_variable, to prevent invalid memory writes
  // when the AutoReset<> object is destroyed.
  template<typename T>
  class AutoReset
  {
  public:
      AutoReset(T* scoped_variable, T new_value)
          : scoped_variable_(scoped_variable),
          original_value_(*scoped_variable)
      {
          *scoped_variable_ = new_value;
      }
  
      ~AutoReset() { *scoped_variable_ = original_value_; }
  
  private:
      T* scoped_variable_;
      T original_value_;
  
      DISALLOW_COPY_AND_ASSIGN(AutoReset);
  };
  
  #endif //__base_auto_reset_h__