michael@0: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef BASE_THREAD_TASK_RUNNER_HANDLE_H_
michael@0: #define BASE_THREAD_TASK_RUNNER_HANDLE_H_
michael@0: 
michael@0: #include "base/base_export.h"
michael@0: #include "base/memory/ref_counted.h"
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: class SingleThreadTaskRunner;
michael@0: 
michael@0: // ThreadTaskRunnerHandle stores a reference to a thread's TaskRunner
michael@0: // in thread-local storage.  Callers can then retrieve the TaskRunner
michael@0: // for the current thread by calling ThreadTaskRunnerHandle::Get().
michael@0: // At most one TaskRunner may be bound to each thread at a time.
michael@0: class BASE_EXPORT ThreadTaskRunnerHandle {
michael@0:  public:
michael@0:   // Gets the SingleThreadTaskRunner for the current thread.
michael@0:   static scoped_refptr<SingleThreadTaskRunner> Get();
michael@0: 
michael@0:   // Returns true if the SingleThreadTaskRunner is already created for
michael@0:   // the current thread.
michael@0:   static bool IsSet();
michael@0: 
michael@0:   // Binds |task_runner| to the current thread. |task_runner| must belong
michael@0:   // to the current thread for this to succeed.
michael@0:   explicit ThreadTaskRunnerHandle(
michael@0:       const scoped_refptr<SingleThreadTaskRunner>& task_runner);
michael@0:   ~ThreadTaskRunnerHandle();
michael@0: 
michael@0:  private:
michael@0:   scoped_refptr<SingleThreadTaskRunner> task_runner_;
michael@0: };
michael@0: 
michael@0: }  // namespace base
michael@0: 
michael@0: #endif  // BASE_THREAD_TASK_RUNNER_HANDLE_H_