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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_SEQUENCE_CHECKER_IMPL_H_
#define BASE_SEQUENCE_CHECKER_IMPL_H_
#include <memory>
#include "base/base_export.h"
#include "base/synchronization/lock.h"
#include "base/thread_annotations.h"
#include "base/threading/thread_checker_impl.h"
namespace base {
namespace debug {
class StackTrace;
}
// Real implementation of SequenceChecker for use in debug mode or for temporary
// use in release mode (e.g. to CHECK on a threading issue seen only in the
// wild).
//
// Note: You should almost always use the SequenceChecker class to get the right
// version for your build configuration.
// Note: This is marked with "context" capability in order to support
// thread_annotations.h.
class THREAD_ANNOTATION_ATTRIBUTE__(capability("context"))
BASE_EXPORT SequenceCheckerImpl {
public:
static void EnableStackLogging();
SequenceCheckerImpl();
// Allow move construct/assign. This must be called on |other|'s associated
// sequence and assignment can only be made into a SequenceCheckerImpl which
// is detached or already associated with the current sequence. This isn't
// thread-safe (|this| and |other| shouldn't be in use while this move is
// performed). If the assignment was legal, the resulting SequenceCheckerImpl
// will be bound to the current sequence and |other| will be detached.
SequenceCheckerImpl(SequenceCheckerImpl&& other);
SequenceCheckerImpl& operator=(SequenceCheckerImpl&& other);
SequenceCheckerImpl(const SequenceCheckerImpl&) = delete;
SequenceCheckerImpl& operator=(const SequenceCheckerImpl&) = delete;
~SequenceCheckerImpl();
// Returns true if called in sequence with previous calls to this method and
// the constructor.
// On returning false, if logging is enabled with EnableStackLogging() and
// `out_bound_at` is not null, this method allocates a StackTrace and returns
// it in the out-parameter, storing inside it the stack from where the failing
// SequenceChecker was bound to its sequence. Otherwise, out_bound_at is left
// untouched.
[[nodiscard]] bool CalledOnValidSequence(
std::unique_ptr<debug::StackTrace>* out_bound_at = nullptr) const;
// Unbinds the checker from the currently associated sequence. The checker
// will be re-bound on the next call to CalledOnValidSequence().
void DetachFromSequence();
private:
// SequenceCheckerImpl uses ThreadCheckerImpl for shared storage.
ThreadCheckerImpl thread_checker_;
};
} // namespace base
#endif // BASE_SEQUENCE_CHECKER_IMPL_H_