61 lines
2.3 KiB
C
61 lines
2.3 KiB
C
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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_THREADING_WORKER_POOL_H_
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#define BASE_THREADING_WORKER_POOL_H_
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#include "base/base_export.h"
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#include "base/callback_forward.h"
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#include "base/memory/ref_counted.h"
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class Task;
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namespace tracked_objects {
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class Location;
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} // namespace tracked_objects
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namespace base {
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class TaskRunner;
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// This is a facility that runs tasks that don't require a specific thread or
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// a message loop.
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//
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// WARNING: This shouldn't be used unless absolutely necessary. We don't wait
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// for the worker pool threads to finish on shutdown, so the tasks running
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// inside the pool must be extremely careful about other objects they access
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// (MessageLoops, Singletons, etc). During shutdown these object may no longer
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// exist.
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class BASE_EXPORT WorkerPool {
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public:
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// This function posts |task| to run on a worker thread. |task_is_slow|
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// should be used for tasks that will take a long time to execute. Returns
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// false if |task| could not be posted to a worker thread. Regardless of
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// return value, ownership of |task| is transferred to the worker pool.
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static bool PostTask(const tracked_objects::Location& from_here,
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const base::Closure& task, bool task_is_slow);
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// Just like MessageLoopProxy::PostTaskAndReply, except the destination
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// for |task| is a worker thread and you can specify |task_is_slow| just
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// like you can for PostTask above.
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static bool PostTaskAndReply(const tracked_objects::Location& from_here,
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const Closure& task,
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const Closure& reply,
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bool task_is_slow);
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// Return true if the current thread is one that this WorkerPool runs tasks
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// on. (Note that if the Windows worker pool is used without going through
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// this WorkerPool interface, RunsTasksOnCurrentThread would return false on
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// those threads.)
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static bool RunsTasksOnCurrentThread();
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// Get a TaskRunner wrapper which posts to the WorkerPool using the given
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// |task_is_slow| behavior.
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static const scoped_refptr<TaskRunner>& GetTaskRunner(bool task_is_slow);
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};
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} // namespace base
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#endif // BASE_THREADING_WORKER_POOL_H_
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