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#include "base/thread_task_runner_handle.h"
6
7#include "base/lazy_instance.h"
8#include "base/single_thread_task_runner.h"
9#include "base/threading/thread_local.h"
10
11namespace base {
12
13namespace {
14
15base::LazyInstance<base::ThreadLocalPointer<ThreadTaskRunnerHandle> >
16    lazy_tls_ptr = LAZY_INSTANCE_INITIALIZER;
17
18}  // namespace
19
20// static
21scoped_refptr<SingleThreadTaskRunner> ThreadTaskRunnerHandle::Get() {
22  ThreadTaskRunnerHandle* current = lazy_tls_ptr.Pointer()->Get();
23  DCHECK(current);
24  return current->task_runner_;
25}
26
27// static
28bool ThreadTaskRunnerHandle::IsSet() {
29  return lazy_tls_ptr.Pointer()->Get() != NULL;
30}
31
32ThreadTaskRunnerHandle::ThreadTaskRunnerHandle(
33    const scoped_refptr<SingleThreadTaskRunner>& task_runner)
34    : task_runner_(task_runner) {
35  DCHECK(task_runner_->BelongsToCurrentThread());
36  DCHECK(!lazy_tls_ptr.Pointer()->Get());
37  lazy_tls_ptr.Pointer()->Set(this);
38}
39
40ThreadTaskRunnerHandle::~ThreadTaskRunnerHandle() {
41  DCHECK(task_runner_->BelongsToCurrentThread());
42  DCHECK_EQ(lazy_tls_ptr.Pointer()->Get(), this);
43  lazy_tls_ptr.Pointer()->Set(NULL);
44}
45
46}  // namespace base
47