Home | History | Annotate | Download | only in base 
      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
     47