// 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. #ifndef BASE_SEQUENCE_CHECKER_IMPL_H_ #define BASE_SEQUENCE_CHECKER_IMPL_H_ #include #include "base/base_export.h" #include "base/synchronization/lock.h" #include "base/thread_annotations.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. bool CalledOnValidSequence(std::unique_ptr* out_bound_at = nullptr) const WARN_UNUSED_RESULT; // Unbinds the checker from the currently associated sequence. The checker // will be re-bound on the next call to CalledOnValidSequence(). void DetachFromSequence(); private: class Core; // Calls straight to ThreadLocalStorage::HasBeenDestroyed(). Exposed purely // for 'friend' to work. static bool HasThreadLocalStorageBeenDestroyed(); mutable Lock lock_; mutable std::unique_ptr core_ GUARDED_BY(lock_); }; } // namespace base #endif // BASE_SEQUENCE_CHECKER_IMPL_H_