1// Copyright 2016 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#include "base/threading/thread_task_runner_handle.h" 6 7#include <utility> 8 9#include "base/lazy_instance.h" 10#include "base/logging.h" 11#include "base/threading/sequenced_task_runner_handle.h" 12#include "base/threading/thread_local.h" 13 14namespace base { 15 16namespace { 17 18base::LazyInstance<base::ThreadLocalPointer<ThreadTaskRunnerHandle>>::Leaky 19 lazy_tls_ptr = LAZY_INSTANCE_INITIALIZER; 20 21} // namespace 22 23// static 24scoped_refptr<SingleThreadTaskRunner> ThreadTaskRunnerHandle::Get() { 25 ThreadTaskRunnerHandle* current = lazy_tls_ptr.Pointer()->Get(); 26 DCHECK(current); 27 return current->task_runner_; 28} 29 30// static 31bool ThreadTaskRunnerHandle::IsSet() { 32 return !!lazy_tls_ptr.Pointer()->Get(); 33} 34 35ThreadTaskRunnerHandle::ThreadTaskRunnerHandle( 36 scoped_refptr<SingleThreadTaskRunner> task_runner) 37 : task_runner_(std::move(task_runner)) { 38 DCHECK(task_runner_->BelongsToCurrentThread()); 39 // No SequencedTaskRunnerHandle (which includes ThreadTaskRunnerHandles) 40 // should already be set for this thread. 41 DCHECK(!SequencedTaskRunnerHandle::IsSet()); 42 lazy_tls_ptr.Pointer()->Set(this); 43} 44 45ThreadTaskRunnerHandle::~ThreadTaskRunnerHandle() { 46 DCHECK(task_runner_->BelongsToCurrentThread()); 47 DCHECK_EQ(lazy_tls_ptr.Pointer()->Get(), this); 48 lazy_tls_ptr.Pointer()->Set(nullptr); 49} 50 51} // namespace base 52