1 // Copyright (c) 2009 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. 4 5 #ifndef BASE_AUTO_RESET_H_ 6 #define BASE_AUTO_RESET_H_ 7 8 #include "base/basictypes.h" 9 10 // AutoReset is useful for setting a variable to some value only during a 11 // particular scope. If you have code that has to add "var = false;" or 12 // "var = old_var;" at all the exit points of a block, for example, you would 13 // benefit from using this instead. 14 // 15 // NOTE: Right now this is hardcoded to work on bools, since that covers all the 16 // cases where we've used it. It would be reasonable to turn it into a template 17 // class in the future. 18 19 class AutoReset { 20 public: 21 explicit AutoReset(bool* scoped_variable, bool new_value) 22 : scoped_variable_(scoped_variable), 23 original_value_(*scoped_variable) { 24 *scoped_variable_ = new_value; 25 } 26 ~AutoReset() { *scoped_variable_ = original_value_; } 27 28 private: 29 bool* scoped_variable_; 30 bool original_value_; 31 32 DISALLOW_COPY_AND_ASSIGN(AutoReset); 33 }; 34 35 #endif // BASE_AUTO_RESET_H_ 36
