base/sequence_checker_impl.cc

   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
   7 namespace base {
   8
   9 SequenceCheckerImpl::SequenceCheckerImpl()
  10     : sequence_token_assigned_(false) {
  11   AutoLock auto_lock(lock_);
  12   EnsureSequenceTokenAssigned();
  13 }
  14
  15 SequenceCheckerImpl::~SequenceCheckerImpl() {}
  16
  17 bool 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
  30 void SequenceCheckerImpl::DetachFromSequence() {
  31   AutoLock auto_lock(lock_);
  32   thread_checker_.DetachFromThread();
  33   sequence_token_assigned_ = false;
  34   sequence_token_ = SequencedWorkerPool::SequenceToken();
  35 }
  36
  37 void 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