| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef BASE_TASK_RUNNER_UTIL_H_ |
| #define BASE_TASK_RUNNER_UTIL_H_ |
| |
| #include <memory> |
| #include <utility> |
| |
| #include "base/bind.h" |
| #include "base/bind_helpers.h" |
| #include "base/callback.h" |
| #include "base/callback_helpers.h" |
| #include "base/logging.h" |
| #include "base/post_task_and_reply_with_result_internal.h" |
| #include "base/task_runner.h" |
| |
| namespace base { |
| |
| // When you have these methods |
| // |
| // R DoWorkAndReturn(); |
| // void Callback(const R& result); |
| // |
| // and want to call them in a PostTaskAndReply kind of fashion where the |
| // result of DoWorkAndReturn is passed to the Callback, you can use |
| // PostTaskAndReplyWithResult as in this example: |
| // |
| // PostTaskAndReplyWithResult( |
| // target_thread_.task_runner(), |
| // FROM_HERE, |
| // BindOnce(&DoWorkAndReturn), |
| // BindOnce(&Callback)); |
| // |
| // Though RepeatingCallback is convertible to OnceCallback, we need a |
| // CallbackType template since we can not use template deduction and object |
| // conversion at once on the overload resolution. |
| // TODO(crbug.com/714018): Update all callers of the RepeatingCallback version |
| // to use OnceCallback and remove the CallbackType template. |
| template <template <typename> class CallbackType, |
| typename TaskReturnType, |
| typename ReplyArgType, |
| typename = EnableIfIsBaseCallback<CallbackType>> |
| bool PostTaskAndReplyWithResult(TaskRunner* task_runner, |
| const Location& from_here, |
| CallbackType<TaskReturnType()> task, |
| CallbackType<void(ReplyArgType)> reply) { |
| DCHECK(task); |
| DCHECK(reply); |
| // std::unique_ptr used to avoid the need of a default constructor. |
| auto* result = new std::unique_ptr<TaskReturnType>(); |
| return task_runner->PostTaskAndReply( |
| from_here, |
| BindOnce(&internal::ReturnAsParamAdapter<TaskReturnType>, std::move(task), |
| result), |
| BindOnce(&internal::ReplyAdapter<TaskReturnType, ReplyArgType>, |
| std::move(reply), Owned(result))); |
| } |
| |
| } // namespace base |
| |
| #endif // BASE_TASK_RUNNER_UTIL_H_ |