1 // Copyright (c) 2012 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 // This defines helpful methods for dealing with Callbacks. Because Callbacks 6 // are implemented using templates, with a class per callback signature, adding 7 // methods to Callback<> itself is unattractive (lots of extra code gets 8 // generated). Instead, consider adding methods here. 9 // 10 // ResetAndReturn(&cb) is like cb.Reset() but allows executing a callback (via a 11 // copy) after the original callback is Reset(). This can be handy if Run() 12 // reads/writes the variable holding the Callback. 13 14 #ifndef BASE_CALLBACK_HELPERS_H_ 15 #define BASE_CALLBACK_HELPERS_H_ 16 17 #include "base/callback.h" 18 19 namespace base { 20 21 template <typename Sig> 22 base::Callback<Sig> ResetAndReturn(base::Callback<Sig>* cb) { 23 base::Callback<Sig> ret(*cb); 24 cb->Reset(); 25 return ret; 26 } 27 28 } // namespace base 29 30 #endif // BASE_CALLBACK_HELPERS_H_ 31
