Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===-- SaveAndRestore.h - Utility  -------------------------------*- C++ -*-=//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

///

/// \file

/// This file provides utility classes that use RAII to save and restore

/// values.

///

//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_SAVEANDRESTORE_H

#define LLVM_SUPPORT_SAVEANDRESTORE_H

#include <utility>

namespace llvm {

/// A utility class that uses RAII to save and restore the value of a variable.

template <typename T> struct SaveAndRestore {

  SaveAndRestore(T &X) : X(X), OldValue(X) {}

  SaveAndRestore(T &X, const T &NewValue) : X(X), OldValue(X) { X = NewValue; }

  SaveAndRestore(T &X, T &&NewValue) : X(X), OldValue(std::move(X)) {

    X = std::move(NewValue);

  }

  ~SaveAndRestore() { X = std::move(OldValue); }

  const T &get() { return OldValue; }

private:

  T &X;

  T OldValue;

};

// User-defined CTAD guides.

template <typename T> SaveAndRestore(T &) -> SaveAndRestore<T>;

template <typename T> SaveAndRestore(T &, const T &) -> SaveAndRestore<T>;

template <typename T> SaveAndRestore(T &, T &&) -> SaveAndRestore<T>;

} // namespace llvm

#endif