base/threading/post_task_and_reply_impl.h

// Copyright (c) 2011 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.

// This file contains the implementation shared by
// TaskRunner::PostTaskAndReply and WorkerPool::PostTaskAndReply.

#ifndef BASE_THREADING_POST_TASK_AND_REPLY_IMPL_H_
#define BASE_THREADING_POST_TASK_AND_REPLY_IMPL_H_

#include "base/base_export.h"
#include "base/callback.h"
#include "base/location.h"

namespace base {
namespace internal {

// Inherit from this in a class that implements PostTask to send a task to a
// custom execution context.
//
// If you're looking for a concrete implementation of PostTaskAndReply, you
// probably want base::TaskRunner, or you may want base::WorkerPool.
class BASE_EXPORT PostTaskAndReplyImpl {
 public:
  virtual ~PostTaskAndReplyImpl() = default;

  // Posts |task| by calling PostTask(). On completion, |reply| is posted to the
  // sequence or thread that called this. Can only be called when
  // SequencedTaskRunnerHandle::IsSet(). Both |task| and |reply| are guaranteed
  // to be deleted on the sequence or thread that called this.
  bool PostTaskAndReply(const tracked_objects::Location& from_here,
                        Closure task,
                        Closure reply);

 private:
  virtual bool PostTask(const tracked_objects::Location& from_here,
                        const Closure& task) = 0;
};

}  // namespace internal
}  // namespace base

#endif  // BASE_THREADING_POST_TASK_AND_REPLY_IMPL_H_