base/threading/sequenced_task_runner_handle.h

// Copyright 2015 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_THREADING_SEQUENCED_TASK_RUNNER_HANDLE_H_
#define BASE_THREADING_SEQUENCED_TASK_RUNNER_HANDLE_H_

#include "base/compiler_specific.h"
#include "base/memory/ref_counted.h"

namespace base {

class SequencedTaskRunner;

class BASE_EXPORT SequencedTaskRunnerHandle {
 public:
  // Returns a SequencedTaskRunner which guarantees that posted tasks will only
  // run after the current task is finished and will satisfy a SequenceChecker.
  // It should only be called if IsSet() returns true (see the comment there for
  // the requirements).
  static scoped_refptr<SequencedTaskRunner> Get();

  // Returns true if one of the following conditions is fulfilled:
  // a) The current thread has a ThreadTaskRunnerHandle (which includes any
  //    thread that has a MessageLoop associated with it), or
  // b) The current thread is a worker thread belonging to a SequencedWorkerPool
  //    *and* is currently running a sequenced task.
  static bool IsSet();

 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(SequencedTaskRunnerHandle);
};

}  // namespace base

#endif  // BASE_THREADING_SEQUENCED_TASK_RUNNER_HANDLE_H_