1424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// Copyright 2013 The Chromium Authors. All rights reserved.
2424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be
3424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// found in the LICENSE file.
4424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)
5424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)#ifndef BASE_BARRIER_CLOSURE_H_
6424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)#define BASE_BARRIER_CLOSURE_H_
7424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)
8424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)#include "base/base_export.h"
9424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)#include "base/callback_forward.h"
10424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)
11424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)namespace base {
12424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)
13424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// BarrierClosure executes |done_closure| after it has been invoked
14424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// |num_closures| times.
15424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)//
16424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// If |num_closures| is 0, |done_closure| is executed immediately.
17424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)//
18424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// BarrierClosure is thread-safe - the count of remaining closures is
19424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// maintained as a base::AtomicRefCount. |done_closure| will be run on
20424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// the thread that calls the final Run() on the returned closures.
21424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)//
22424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// |done_closure| is also Reset() on the final calling thread but due to the
23424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// refcounted nature of callbacks, it is hard to know what thread resources
24424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)// will be released on.
25424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)BASE_EXPORT base::Closure BarrierClosure(int num_closures,
26424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)                                         const base::Closure& done_closure);
27424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)
28424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)}  // namespace base
29424c4d7b64af9d0d8fd9624f381f469654d5e3d2Torne (Richard Coles)
30d0247b1b59f9c528cb6df88b4f2b9afaf80d181eTorne (Richard Coles)#endif  // BASE_BARRIER_CLOSURE_H_
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