| // 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 "base/bind.h" |
| #include "base/bind_helpers.h" |
| #include "base/callback_internal.h" |
| #include "base/logging.h" |
| #include "base/task_runner.h" |
| |
| namespace base { |
| |
| namespace internal { |
| |
| // Helper class for TaskRunner::PostTaskAndReplyWithResult. |
| template <typename ReturnType> |
| void ReturnAsParamAdapter(const Callback<ReturnType(void)>& func, |
| ReturnType* result) { |
| if (!func.is_null()) |
| *result = func.Run(); |
| } |
| |
| // Helper class for TaskRunner::PostTaskAndReplyWithResult. |
| template <typename ReturnType> |
| Closure ReturnAsParam(const Callback<ReturnType(void)>& func, |
| ReturnType* result) { |
| DCHECK(result); |
| return Bind(&ReturnAsParamAdapter<ReturnType>, func, result); |
| } |
| |
| // Helper class for TaskRunner::PostTaskAndReplyWithResult. |
| template <typename ReturnType> |
| void ReplyAdapter(const Callback<void(ReturnType)>& callback, |
| ReturnType* result) { |
| DCHECK(result); |
| if(!callback.is_null()) |
| callback.Run(CallbackForward(*result)); |
| } |
| |
| // Helper class for TaskRunner::PostTaskAndReplyWithResult. |
| template <typename ReturnType, typename OwnedType> |
| Closure ReplyHelper(const Callback<void(ReturnType)>& callback, |
| OwnedType result) { |
| return Bind(&ReplyAdapter<ReturnType>, callback, result); |
| } |
| |
| } // namespace internal |
| |
| // 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_.message_loop_proxy(), |
| // FROM_HERE, |
| // Bind(&DoWorkAndReturn), |
| // Bind(&Callback)); |
| template <typename ReturnType> |
| bool PostTaskAndReplyWithResult( |
| TaskRunner* task_runner, |
| const tracked_objects::Location& from_here, |
| const Callback<ReturnType(void)>& task, |
| const Callback<void(ReturnType)>& reply) { |
| ReturnType* result = new ReturnType; |
| return task_runner->PostTaskAndReply( |
| from_here, |
| internal::ReturnAsParam<ReturnType>(task, result), |
| internal::ReplyHelper(reply, Owned(result))); |
| } |
| |
| } // namespace base |
| |
| #endif // BASE_TASK_RUNNER_UTIL_H_ |