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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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_RAII AutoRestore
{
private:
T& mLocation;
T mValue;
MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
public:
explicit AutoRestore(T& aValue MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: mLocation(aValue)
, mValue(aValue)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
}
~AutoRestore()
{
mLocation = mValue;
}
T SavedValue() const
{
return mValue;
}
};
} // namespace mozilla
#endif /* !defined(mozilla_AutoRestore_h_) */
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