sequence_checker_impl.h

Enable keyboard shortcuts

// 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 <memory>

#include "base/base_export.h"

#include "base/compiler_specific.h"

#include "base/macros.h"

#include "base/synchronization/lock.h"

#include "base/thread_annotations.h"

namespace base {

// 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 only a check, not a "lock". It is marked "LOCKABLE" only in

// order to support thread_annotations.h.

class LOCKABLE BASE_EXPORT SequenceCheckerImpl {

 public:

  SequenceCheckerImpl();

  ~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);

  // Returns true if called in sequence with previous calls to this method and

  // the constructor.

  bool CalledOnValidSequence() 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> core_ GUARDED_BY(lock_);

  DISALLOW_COPY_AND_ASSIGN(SequenceCheckerImpl);

};

}  // namespace base

#endif  // BASE_SEQUENCE_CHECKER_IMPL_H_