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 /* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 /* functions for restoring saved values at the end of a C++ scope */

 #ifndef mozilla_AutoRestore_h_

 #define mozilla_AutoRestore_h_

 #include "mozilla/Attributes.h" // MOZ_STACK_CLASS

 #include "mozilla/GuardObjects.h"

 namespace mozilla {

   /**

    * Save the current value of a variable and restore it when the object

    * goes out of scope.  For example:

    *   {

    *     AutoRestore<bool> savePainting(mIsPainting);

    *     mIsPainting = true;

    *     

    *     // ... your code here ...

    *

    *     // mIsPainting is reset to its old value at the end of this block

    *   }

    */

   template <class T>

   class MOZ_STACK_CLASS AutoRestore

   {

   private:

     T& mLocation;

     T mValue;

     MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER

   public:

     AutoRestore(T& aValue MOZ_GUARD_OBJECT_NOTIFIER_PARAM)

       : mLocation(aValue), mValue(aValue)

     {

       MOZ_GUARD_OBJECT_NOTIFIER_INIT;

     }

     ~AutoRestore() { mLocation = mValue; }

   };

 } // namespace mozilla

 #endif /* !defined(mozilla_AutoRestore_h_) */