barrier_closure.cc 1.4 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556
  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. #include "base/barrier_closure.h"
  5. #include <utility>
  6. #include "base/atomic_ref_count.h"
  7. #include "base/bind.h"
  8. #include "base/memory/ptr_util.h"
  9. #include "base/numerics/safe_conversions.h"
  10. namespace base {
  11. namespace {
  12. // Maintains state for a BarrierClosure.
  13. class BarrierInfo {
  14. public:
  15. BarrierInfo(size_t num_callbacks_left, OnceClosure done_closure);
  16. void Run();
  17. private:
  18. AtomicRefCount num_callbacks_left_;
  19. OnceClosure done_closure_;
  20. };
  21. BarrierInfo::BarrierInfo(size_t num_callbacks, OnceClosure done_closure)
  22. : num_callbacks_left_(checked_cast<int>(num_callbacks)),
  23. done_closure_(std::move(done_closure)) {}
  24. void BarrierInfo::Run() {
  25. DCHECK(!num_callbacks_left_.IsZero());
  26. if (!num_callbacks_left_.Decrement())
  27. std::move(done_closure_).Run();
  28. }
  29. void ShouldNeverRun() {
  30. CHECK(false);
  31. }
  32. } // namespace
  33. RepeatingClosure BarrierClosure(size_t num_callbacks_left,
  34. OnceClosure done_closure) {
  35. if (num_callbacks_left == 0) {
  36. std::move(done_closure).Run();
  37. return BindRepeating(&ShouldNeverRun);
  38. }
  39. return BindRepeating(&BarrierInfo::Run,
  40. std::make_unique<BarrierInfo>(num_callbacks_left,
  41. std::move(done_closure)));
  42. }
  43. } // namespace base