base/sequence_token.cc

   1 // Copyright 2016 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_token.h"
   6
   7 #include "base/atomic_sequence_num.h"
   8 #include "base/lazy_instance.h"
   9 #include "base/logging.h"
  10 #include "base/threading/thread_local.h"
  11
  12 namespace base {
  13
  14 namespace {
  15
  16 base::AtomicSequenceNumber g_sequence_token_generator;
  17
  18 base::AtomicSequenceNumber g_task_token_generator;
  19
  20 LazyInstance<ThreadLocalPointer<const SequenceToken>>::Leaky
  21     tls_current_sequence_token = LAZY_INSTANCE_INITIALIZER;
  22
  23 LazyInstance<ThreadLocalPointer<const TaskToken>>::Leaky
  24     tls_current_task_token = LAZY_INSTANCE_INITIALIZER;
  25
  26 }  // namespace
  27
  28 bool SequenceToken::operator==(const SequenceToken& other) const {
  29   return token_ == other.token_ && IsValid();
  30 }
  31
  32 bool SequenceToken::operator!=(const SequenceToken& other) const {
  33   return !(*this == other);
  34 }
  35
  36 bool SequenceToken::IsValid() const {
  37   return token_ != kInvalidSequenceToken;
  38 }
  39
  40 int SequenceToken::ToInternalValue() const {
  41   return token_;
  42 }
  43
  44 SequenceToken SequenceToken::Create() {
  45   return SequenceToken(g_sequence_token_generator.GetNext());
  46 }
  47
  48 SequenceToken SequenceToken::GetForCurrentThread() {
  49   const SequenceToken* current_sequence_token =
  50       tls_current_sequence_token.Get().Get();
  51   return current_sequence_token ? *current_sequence_token : SequenceToken();
  52 }
  53
  54 bool TaskToken::operator==(const TaskToken& other) const {
  55   return token_ == other.token_ && IsValid();
  56 }
  57
  58 bool TaskToken::operator!=(const TaskToken& other) const {
  59   return !(*this == other);
  60 }
  61
  62 bool TaskToken::IsValid() const {
  63   return token_ != kInvalidTaskToken;
  64 }
  65
  66 TaskToken TaskToken::Create() {
  67   return TaskToken(g_task_token_generator.GetNext());
  68 }
  69
  70 TaskToken TaskToken::GetForCurrentThread() {
  71   const TaskToken* current_task_token = tls_current_task_token.Get().Get();
  72   return current_task_token ? *current_task_token : TaskToken();
  73 }
  74
  75 ScopedSetSequenceTokenForCurrentThread::ScopedSetSequenceTokenForCurrentThread(
  76     const SequenceToken& sequence_token)
  77     : sequence_token_(sequence_token), task_token_(TaskToken::Create()) {
  78   DCHECK(!tls_current_sequence_token.Get().Get());
  79   DCHECK(!tls_current_task_token.Get().Get());
  80   tls_current_sequence_token.Get().Set(&sequence_token_);
  81   tls_current_task_token.Get().Set(&task_token_);
  82 }
  83
  84 ScopedSetSequenceTokenForCurrentThread::
  85     ~ScopedSetSequenceTokenForCurrentThread() {
  86   DCHECK_EQ(tls_current_sequence_token.Get().Get(), &sequence_token_);
  87   DCHECK_EQ(tls_current_task_token.Get().Get(), &task_token_);
  88   tls_current_sequence_token.Get().Set(nullptr);
  89   tls_current_task_token.Get().Set(nullptr);
  90 }
  91
  92 }  // namespace base