// Copyright 2013 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "base/barrier_closure.h" #include #include "base/atomic_ref_count.h" #include "base/bind.h" #include "base/memory/ptr_util.h" #include "base/numerics/safe_conversions.h" namespace base { namespace { // Maintains state for a BarrierClosure. class BarrierInfo { public: BarrierInfo(size_t num_callbacks_left, OnceClosure done_closure); void Run(); private: AtomicRefCount num_callbacks_left_; OnceClosure done_closure_; }; BarrierInfo::BarrierInfo(size_t num_callbacks, OnceClosure done_closure) : num_callbacks_left_(checked_cast(num_callbacks)), done_closure_(std::move(done_closure)) {} void BarrierInfo::Run() { DCHECK(!num_callbacks_left_.IsZero()); if (!num_callbacks_left_.Decrement()) std::move(done_closure_).Run(); } void ShouldNeverRun() { CHECK(false); } } // namespace RepeatingClosure BarrierClosure(size_t num_callbacks_left, OnceClosure done_closure) { if (num_callbacks_left == 0) { std::move(done_closure).Run(); return BindRepeating(&ShouldNeverRun); } return BindRepeating(&BarrierInfo::Run, std::make_unique(num_callbacks_left, std::move(done_closure))); } } // namespace base