blob: e911cec1d65261d89efa9c1cc5df344cfdeea2ea [file] [log] [blame]
// Copyright (c) 2011 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/base_export.h"
#include "base/compiler_specific.h"
#include "base/sequence_token.h"
#include "base/synchronization/lock.h"
#include "base/thread_annotations.h"
#include "base/threading/platform_thread.h"
namespace base {
// Real implementation of ThreadChecker, 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 ThreadChecker class to get the right
// version for your build configuration.
class BASE_EXPORT ThreadCheckerImpl {
// Allow move construct/assign. This must be called on |other|'s associated
// thread and assignment can only be made into a ThreadCheckerImpl which is
// detached or already associated with the current thread. 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 ThreadCheckerImpl
// will be bound to the current thread and |other| will be detached.
ThreadCheckerImpl(ThreadCheckerImpl&& other);
ThreadCheckerImpl& operator=(ThreadCheckerImpl&& other);
bool CalledOnValidThread() const WARN_UNUSED_RESULT;
// Changes the thread that is checked for in CalledOnValidThread. This may
// be useful when an object may be created on one thread and then used
// exclusively on another thread.
void DetachFromThread();
void EnsureAssignedLockRequired() const EXCLUSIVE_LOCKS_REQUIRED(lock_);
// Members are mutable so that CalledOnValidThread() can set them.
// Synchronizes access to all members.
mutable base::Lock lock_;
// Thread on which CalledOnValidThread() may return true.
mutable PlatformThreadRef thread_id_ GUARDED_BY(lock_);
// TaskToken for which CalledOnValidThread() always returns true. This allows
// CalledOnValidThread() to return true when called multiple times from the
// same task, even if it's not running in a single-threaded context itself
// (allowing usage of ThreadChecker objects on the stack in the scope of one-
// off tasks). Note: CalledOnValidThread() may return true even if the current
// TaskToken is not equal to this.
mutable TaskToken task_token_ GUARDED_BY(lock_);
// SequenceToken for which CalledOnValidThread() may return true. Used to
// ensure that CalledOnValidThread() doesn't return true for ThreadPool
// tasks that happen to run on the same thread but weren't posted to the same
// SingleThreadTaskRunner.
mutable SequenceToken sequence_token_ GUARDED_BY(lock_);
} // namespace base