// Copyright 2015 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/threading/sequenced_task_runner_handle.h"

#include "base/sequenced_task_runner.h"
#include "base/thread_task_runner_handle.h"
#include "base/threading/sequenced_worker_pool.h"

namespace base {

// static
scoped_refptr<SequencedTaskRunner> SequencedTaskRunnerHandle::Get() {
  // If we are on a worker thread for a SequencedBlockingPool that is running a
  // sequenced task, return a SequencedTaskRunner for it.
  scoped_refptr<base::SequencedWorkerPool> pool =
      SequencedWorkerPool::GetWorkerPoolForCurrentThread();
  if (pool) {
    SequencedWorkerPool::SequenceToken sequence_token =
        SequencedWorkerPool::GetSequenceTokenForCurrentThread();
    DCHECK(sequence_token.IsValid());
    DCHECK(pool->IsRunningSequenceOnCurrentThread(sequence_token));
    return pool->GetSequencedTaskRunner(sequence_token);
  }

  // Otherwise, return a SingleThreadTaskRunner for the current thread.
  return base::ThreadTaskRunnerHandle::Get();
}

// static
bool SequencedTaskRunnerHandle::IsSet() {
  return (SequencedWorkerPool::GetWorkerPoolForCurrentThread() &&
          SequencedWorkerPool::GetSequenceTokenForCurrentThread().IsValid()) ||
         base::ThreadTaskRunnerHandle::IsSet();
}

}  // namespace base