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- // Copyright (c) 2012 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_checker_impl.h"
- #include <utility>
- #include "base/check.h"
- #include "base/debug/stack_trace.h"
- #include "base/memory/ptr_util.h"
- #include "base/sequence_token.h"
- #include "base/threading/thread_checker.h"
- #include "base/threading/thread_checker_impl.h"
- #include "base/threading/thread_local_storage.h"
- namespace base {
- // static
- void SequenceCheckerImpl::EnableStackLogging() {
- ThreadChecker::EnableStackLogging();
- }
- class SequenceCheckerImpl::Core {
- public:
- Core() : sequence_token_(SequenceToken::GetForCurrentThread()) {}
- ~Core() = default;
- bool CalledOnValidSequence(
- std::unique_ptr<debug::StackTrace>* out_bound_at) const {
- // SequenceToken::GetForCurrentThread() accesses thread-local storage.
- // During destruction the state of thread-local storage is not guaranteed to
- // be in a consistent state. Further, task-runner only installs the
- // SequenceToken when running a task. For this reason, |sequence_token_| is
- // not checked during thread destruction.
- if (!SequenceCheckerImpl::HasThreadLocalStorageBeenDestroyed() &&
- sequence_token_.IsValid()) {
- if (sequence_token_ != SequenceToken::GetForCurrentThread()) {
- if (out_bound_at)
- *out_bound_at = thread_checker_.GetBoundAt();
- return false;
- }
- return true;
- }
- // SequenceChecker behaves as a ThreadChecker when it is not bound to a
- // valid sequence token.
- return thread_checker_.CalledOnValidThread(out_bound_at);
- }
- private:
- SequenceToken sequence_token_{SequenceToken::GetForCurrentThread()};
- // Used when |sequence_token_| is invalid, or during thread destruction.
- ThreadCheckerImpl thread_checker_;
- };
- SequenceCheckerImpl::SequenceCheckerImpl() : core_(std::make_unique<Core>()) {}
- SequenceCheckerImpl::~SequenceCheckerImpl() = default;
- SequenceCheckerImpl::SequenceCheckerImpl(SequenceCheckerImpl&& other) {
- // Verify that |other| is called on its associated sequence and bind it now if
- // it is currently detached (even if this isn't a DCHECK build).
- const bool other_called_on_valid_sequence = other.CalledOnValidSequence();
- DCHECK(other_called_on_valid_sequence);
- core_ = std::move(other.core_);
- }
- SequenceCheckerImpl& SequenceCheckerImpl::operator=(
- SequenceCheckerImpl&& other) {
- // If |this| is not in a detached state it needs to be bound to the current
- // sequence.
- DCHECK(CalledOnValidSequence());
- // Verify that |other| is called on its associated sequence and bind it now if
- // it is currently detached (even if this isn't a DCHECK build).
- const bool other_called_on_valid_sequence = other.CalledOnValidSequence();
- DCHECK(other_called_on_valid_sequence);
- // Intentionally not using either |lock_| in this method to let TSAN catch
- // racy assign.
- TS_UNCHECKED_READ(core_) = std::move(TS_UNCHECKED_READ(other.core_));
- return *this;
- }
- bool SequenceCheckerImpl::CalledOnValidSequence(
- std::unique_ptr<debug::StackTrace>* bound_at) const {
- AutoLock auto_lock(lock_);
- if (!core_)
- core_ = std::make_unique<Core>();
- return core_->CalledOnValidSequence(bound_at);
- }
- void SequenceCheckerImpl::DetachFromSequence() {
- AutoLock auto_lock(lock_);
- core_.reset();
- }
- // static
- bool SequenceCheckerImpl::HasThreadLocalStorageBeenDestroyed() {
- return ThreadLocalStorage::HasBeenDestroyed();
- }
- } // namespace base
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