1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_THREAD_TASK_RUNNER_HANDLE_H_
6#define BASE_THREAD_TASK_RUNNER_HANDLE_H_
7
8#include "base/base_export.h"
9#include "base/memory/ref_counted.h"
10
11namespace base {
12
13class SingleThreadTaskRunner;
14
15// ThreadTaskRunnerHandle stores a reference to a thread's TaskRunner
16// in thread-local storage.  Callers can then retrieve the TaskRunner
17// for the current thread by calling ThreadTaskRunnerHandle::Get().
18// At most one TaskRunner may be bound to each thread at a time.
19class BASE_EXPORT ThreadTaskRunnerHandle {
20 public:
21  // Gets the SingleThreadTaskRunner for the current thread.
22  static scoped_refptr<SingleThreadTaskRunner> Get();
23
24  // Returns true if the SingleThreadTaskRunner is already created for
25  // the current thread.
26  static bool IsSet();
27
28  // Binds |task_runner| to the current thread. |task_runner| must belong
29  // to the current thread for this to succeed.
30  explicit ThreadTaskRunnerHandle(
31      const scoped_refptr<SingleThreadTaskRunner>& task_runner);
32  ~ThreadTaskRunnerHandle();
33
34 private:
35  scoped_refptr<SingleThreadTaskRunner> task_runner_;
36};
37
38}  // namespace base
39
40#endif  // BASE_THREAD_TASK_RUNNER_HANDLE_H_
41