| // Copyright 2016 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/sequence_token.h" |
| |
| #include "base/atomic_sequence_num.h" |
| #include "base/lazy_instance.h" |
| #include "base/logging.h" |
| #include "base/threading/thread_local.h" |
| |
| namespace base { |
| |
| namespace { |
| |
| base::StaticAtomicSequenceNumber g_sequence_token_generator; |
| |
| LazyInstance<ThreadLocalPointer<ScopedSetSequenceTokenForCurrentThread>>::Leaky |
| tls_current_sequence_token = LAZY_INSTANCE_INITIALIZER; |
| |
| } // namespace |
| |
| bool SequenceToken::operator==(const SequenceToken& other) const { |
| return token_ == other.token_ && token_ != kInvalidSequenceToken; |
| } |
| |
| bool SequenceToken::operator!=(const SequenceToken& other) const { |
| return !(*this == other); |
| } |
| |
| bool SequenceToken::IsValid() const { |
| return token_ != kInvalidSequenceToken; |
| } |
| |
| SequenceToken SequenceToken::Create() { |
| return SequenceToken(g_sequence_token_generator.GetNext()); |
| } |
| |
| SequenceToken SequenceToken::GetForCurrentThread() { |
| const ScopedSetSequenceTokenForCurrentThread* current_sequence_token = |
| tls_current_sequence_token.Get().Get(); |
| return current_sequence_token ? current_sequence_token->token_ |
| : SequenceToken(); |
| } |
| |
| ScopedSetSequenceTokenForCurrentThread::ScopedSetSequenceTokenForCurrentThread( |
| const SequenceToken& token) |
| : token_(token) { |
| DCHECK(!tls_current_sequence_token.Get().Get()); |
| tls_current_sequence_token.Get().Set(this); |
| } |
| |
| ScopedSetSequenceTokenForCurrentThread:: |
| ~ScopedSetSequenceTokenForCurrentThread() { |
| DCHECK_EQ(tls_current_sequence_token.Get().Get(), this); |
| tls_current_sequence_token.Get().Set(nullptr); |
| } |
| |
| } // namespace base |