1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef BASE_AUTO_RESET_H_
6 #define BASE_AUTO_RESET_H_
10 #include "base/macros.h"
12 // base::AutoReset<> is useful for setting a variable to a new value only within
13 // a particular scope. An base::AutoReset<> object resets a variable to its
14 // original value upon destruction, making it an alternative to writing
15 // "var = false;" or "var = old_val;" at all of a block's exit points.
17 // This should be obvious, but note that an base::AutoReset<> instance should
18 // have a shorter lifetime than its scoped_variable, to prevent invalid memory
19 // writes when the base::AutoReset<> object is destroyed.
26 AutoReset(T* scoped_variable, T new_value)
27 : scoped_variable_(scoped_variable),
28 original_value_(std::move(*scoped_variable)) {
29 *scoped_variable_ = std::move(new_value);
32 ~AutoReset() { *scoped_variable_ = std::move(original_value_); }
38 DISALLOW_COPY_AND_ASSIGN(AutoReset);
43 #endif // BASE_AUTO_RESET_H_