base/barrier_closure.h

   1 // Copyright 2013 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.
   4
   5 #ifndef BASE_BARRIER_CLOSURE_H_
   6 #define BASE_BARRIER_CLOSURE_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/callback_forward.h"
  10
  11 namespace base {
  12
  13 // BarrierClosure executes |done_closure| after it has been invoked
  14 // |num_closures| times.
  15 //
  16 // If |num_closures| is 0, |done_closure| is executed immediately.
  17 //
  18 // BarrierClosure is thread-safe - the count of remaining closures is
  19 // maintained as a base::AtomicRefCount. |done_closure| will be run on
  20 // the thread that calls the final Run() on the returned closures.
  21 //
  22 // |done_closure| is also Reset() on the final calling thread but due to the
  23 // refcounted nature of callbacks, it is hard to know what thread resources
  24 // will be released on.
  25 BASE_EXPORT base::Closure BarrierClosure(int num_closures,
  26                                          const base::Closure& done_closure);
  27
  28 }  // namespace base
  29
  30 #endif  // BASE_BARRIER_CLOSURE_H_