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94 lines
3.6 KiB
C++
94 lines
3.6 KiB
C++
// Copyright 2012 The Chromium Authors
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_SEQUENCE_CHECKER_IMPL_H_
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#define BASE_SEQUENCE_CHECKER_IMPL_H_
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#include <cstdint>
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#include <memory>
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#include <vector>
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#include "base/base_export.h"
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#include "base/sequence_token.h"
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#include "base/synchronization/lock.h"
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#include "base/thread_annotations.h"
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#include "base/threading/platform_thread_ref.h"
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namespace base {
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namespace debug {
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class StackTrace;
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}
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// Real implementation of SequenceChecker.
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//
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// In most cases, SEQUENCE_CHECKER should be used instead of this, get the right
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// implementation for the build configuration. It's possible to temporarily use
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// this directly to get sequence checking in production builds, which can be
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// handy to debug issues only seen in the field. However, when used in a
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// non-DCHECK build, SequenceCheckerImpl::CalledOnValidSequence() will not
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// consider locks as a valid way to guarantee mutual exclusion (returns false if
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// not invoked from the bound sequence, even if all calls are made under the
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// same lock).
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// Marked with "context" capability to support thread_annotations.h.
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class THREAD_ANNOTATION_ATTRIBUTE__(capability("context"))
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BASE_EXPORT SequenceCheckerImpl {
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public:
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static void EnableStackLogging();
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SequenceCheckerImpl();
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// Allow move construct/assign. This must be called on |other|'s associated
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// sequence and assignment can only be made into a SequenceCheckerImpl which
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// is detached or already associated with the current sequence. This isn't
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// thread-safe (|this| and |other| shouldn't be in use while this move is
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// performed). If the assignment was legal, the resulting SequenceCheckerImpl
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// will be bound to the current sequence and |other| will be detached.
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SequenceCheckerImpl(SequenceCheckerImpl&& other);
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SequenceCheckerImpl& operator=(SequenceCheckerImpl&& other);
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SequenceCheckerImpl(const SequenceCheckerImpl&) = delete;
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SequenceCheckerImpl& operator=(const SequenceCheckerImpl&) = delete;
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~SequenceCheckerImpl();
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// Returns true if called in sequence with previous calls to this method and
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// the constructor.
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// On returning false, if logging is enabled with EnableStackLogging() and
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// `out_bound_at` is not null, this method allocates a StackTrace and returns
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// it in the out-parameter, storing inside it the stack from where the failing
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// SequenceChecker was bound to its sequence. Otherwise, out_bound_at is left
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// untouched.
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[[nodiscard]] bool CalledOnValidSequence(
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std::unique_ptr<debug::StackTrace>* out_bound_at = nullptr) const;
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// Unbinds the checker from the currently associated sequence. The checker
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// will be re-bound on the next call to CalledOnValidSequence().
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void DetachFromSequence();
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private:
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void EnsureAssigned() const EXCLUSIVE_LOCKS_REQUIRED(lock_);
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// Members are mutable so that `CalledOnValidSequence()` can set them.
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mutable Lock lock_;
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// Stack from which this was bound (set if `EnableStackLogging()` was called).
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mutable std::unique_ptr<debug::StackTrace> bound_at_ GUARDED_BY(lock_);
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// Sequence to which this is bound.
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mutable internal::SequenceToken sequence_token_ GUARDED_BY(lock_);
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#if DCHECK_IS_ON()
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// Locks to which this is bound.
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mutable std::vector<uintptr_t> locks_ GUARDED_BY(lock_);
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#endif // DCHECK_IS_ON()
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// Thread to which this is bound. Only used to evaluate
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// `CalledOnValidSequence()` after TLS destruction.
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mutable PlatformThreadRef thread_ref_ GUARDED_BY(lock_);
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};
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} // namespace base
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#endif // BASE_SEQUENCE_CHECKER_IMPL_H_
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