1 // Copyright (c) 2012 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.
5 #ifndef BASE_THREADING_WORKER_POOL_H_
6 #define BASE_THREADING_WORKER_POOL_H_
8 #include "base/base_export.h"
9 #include "base/callback_forward.h"
10 #include "base/memory/ref_counted.h"
14 namespace tracked_objects
{
16 } // namespace tracked_objects
22 // This is a facility that runs tasks that don't require a specific thread or
25 // WARNING: This shouldn't be used unless absolutely necessary. We don't wait
26 // for the worker pool threads to finish on shutdown, so the tasks running
27 // inside the pool must be extremely careful about other objects they access
28 // (MessageLoops, Singletons, etc). During shutdown these object may no longer
30 class BASE_EXPORT WorkerPool
{
32 // This function posts |task| to run on a worker thread. |task_is_slow|
33 // should be used for tasks that will take a long time to execute. Returns
34 // false if |task| could not be posted to a worker thread. Regardless of
35 // return value, ownership of |task| is transferred to the worker pool.
36 static bool PostTask(const tracked_objects::Location
& from_here
,
37 const base::Closure
& task
, bool task_is_slow
);
39 // Just like TaskRunner::PostTaskAndReply, except the destination
40 // for |task| is a worker thread and you can specify |task_is_slow| just
41 // like you can for PostTask above.
42 static bool PostTaskAndReply(const tracked_objects::Location
& from_here
,
47 // Return true if the current thread is one that this WorkerPool runs tasks
48 // on. (Note that if the Windows worker pool is used without going through
49 // this WorkerPool interface, RunsTasksOnCurrentThread would return false on
51 static bool RunsTasksOnCurrentThread();
53 // Get a TaskRunner wrapper which posts to the WorkerPool using the given
54 // |task_is_slow| behavior.
55 static const scoped_refptr
<TaskRunner
>& GetTaskRunner(bool task_is_slow
);
60 #endif // BASE_THREADING_WORKER_POOL_H_