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)#ifndef BASE_TASK_RUNNER_UTIL_H_ 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#define BASE_TASK_RUNNER_UTIL_H_ 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/bind.h" 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/bind_helpers.h" 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/callback_internal.h" 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/logging.h" 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/task_runner.h" 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace base { 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace internal { 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 182a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// Adapts a function that produces a result via a return value to 192a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// one that returns via an output parameter. 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)template <typename ReturnType> 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void ReturnAsParamAdapter(const Callback<ReturnType(void)>& func, 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ReturnType* result) { 232a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) *result = func.Run(); 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 262a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)// Adapts a T* result to a callblack that expects a T. 272a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)template <typename TaskReturnType, typename ReplyArgType> 282a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)void ReplyAdapter(const Callback<void(ReplyArgType)>& callback, 292a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) TaskReturnType* result) { 302a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // TODO(ajwong): Remove this conditional and add a DCHECK to enforce that 312a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // |reply| must be non-null in PostTaskAndReplyWithResult() below after 322a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // current code that relies on this API softness has been removed. 332a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) // http://crbug.com/162712 342a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) if (!callback.is_null()) 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) callback.Run(CallbackForward(*result)); 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace internal 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// When you have these methods 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// R DoWorkAndReturn(); 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// void Callback(const R& result); 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// and want to call them in a PostTaskAndReply kind of fashion where the 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// result of DoWorkAndReturn is passed to the Callback, you can use 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// PostTaskAndReplyWithResult as in this example: 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// PostTaskAndReplyWithResult( 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// target_thread_.message_loop_proxy(), 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// FROM_HERE, 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Bind(&DoWorkAndReturn), 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Bind(&Callback)); 542a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles)template <typename TaskReturnType, typename ReplyArgType> 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool PostTaskAndReplyWithResult( 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) TaskRunner* task_runner, 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const tracked_objects::Location& from_here, 582a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) const Callback<TaskReturnType(void)>& task, 592a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) const Callback<void(ReplyArgType)>& reply) { 602a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) TaskReturnType* result = new TaskReturnType(); 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return task_runner->PostTaskAndReply( 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) from_here, 632a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) base::Bind(&internal::ReturnAsParamAdapter<TaskReturnType>, task, 642a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) result), 652a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) base::Bind(&internal::ReplyAdapter<TaskReturnType, ReplyArgType>, reply, 662a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) base::Owned(result))); 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace base 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif // BASE_TASK_RUNNER_UTIL_H_ 72