15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This defines helpful methods for dealing with Callbacks. Because Callbacks 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// are implemented using templates, with a class per callback signature, adding 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// methods to Callback<> itself is unattractive (lots of extra code gets 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// generated). Instead, consider adding methods here. 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// ResetAndReturn(&cb) is like cb.Reset() but allows executing a callback (via a 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// copy) after the original callback is Reset(). This can be handy if Run() 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// reads/writes the variable holding the Callback. 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#ifndef BASE_CALLBACK_HELPERS_H_ 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_CALLBACK_HELPERS_H_ 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 17424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)#include "base/basictypes.h" 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/callback.h" 19424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)#include "base/compiler_specific.h" 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace base { 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <typename Sig> 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)base::Callback<Sig> ResetAndReturn(base::Callback<Sig>* cb) { 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::Callback<Sig> ret(*cb); 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) cb->Reset(); 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ret; 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 30424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// ScopedClosureRunner is akin to scoped_ptr for Closures. It ensures that the 31424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// Closure is executed and deleted no matter how the current scope exits. 32424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)class BASE_EXPORT ScopedClosureRunner { 33424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) public: 34424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) ScopedClosureRunner(); 35424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) explicit ScopedClosureRunner(const Closure& closure); 36424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) ~ScopedClosureRunner(); 37424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) 38424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) void Reset(); 39424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) void Reset(const Closure& closure); 40424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) Closure Release() WARN_UNUSED_RESULT; 41424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) 42424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) private: 43424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) Closure closure_; 44424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) 45424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) DISALLOW_COPY_AND_ASSIGN(ScopedClosureRunner); 46424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)}; 47424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles) 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace base 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_CALLBACK_HELPERS_H_ 51