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/sequence_checker_impl.h"
6
7namespace base {
8
9SequenceCheckerImpl::SequenceCheckerImpl()
10    : sequence_token_assigned_(false) {
11  AutoLock auto_lock(lock_);
12  EnsureSequenceTokenAssigned();
13}
14
15SequenceCheckerImpl::~SequenceCheckerImpl() {}
16
17bool SequenceCheckerImpl::CalledOnValidSequencedThread() const {
18  AutoLock auto_lock(lock_);
19  EnsureSequenceTokenAssigned();
20
21  // If this thread is not associated with a SequencedWorkerPool,
22  // SequenceChecker behaves as a ThreadChecker. See header for details.
23  if (!sequence_token_.IsValid())
24    return thread_checker_.CalledOnValidThread();
25
26  return sequence_token_.Equals(
27      SequencedWorkerPool::GetSequenceTokenForCurrentThread());
28}
29
30void SequenceCheckerImpl::DetachFromSequence() {
31  AutoLock auto_lock(lock_);
32  thread_checker_.DetachFromThread();
33  sequence_token_assigned_ = false;
34  sequence_token_ = SequencedWorkerPool::SequenceToken();
35}
36
37void SequenceCheckerImpl::EnsureSequenceTokenAssigned() const {
38  lock_.AssertAcquired();
39  if (sequence_token_assigned_)
40    return;
41
42  sequence_token_assigned_ = true;
43  sequence_token_ = SequencedWorkerPool::GetSequenceTokenForCurrentThread();
44}
45
46}  // namespace base
47