supports_user_data.cc 2.3 KB

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  1. // Copyright (c) 2012 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/supports_user_data.h"
  5. #include "base/sequence_checker.h"
  6. namespace base {
  7. std::unique_ptr<SupportsUserData::Data> SupportsUserData::Data::Clone() {
  8. return nullptr;
  9. }
  10. SupportsUserData::SupportsUserData() {
  11. // Harmless to construct on a different execution sequence to subsequent
  12. // usage.
  13. DETACH_FROM_SEQUENCE(sequence_checker_);
  14. }
  15. SupportsUserData::SupportsUserData(SupportsUserData&&) = default;
  16. SupportsUserData& SupportsUserData::operator=(SupportsUserData&&) = default;
  17. SupportsUserData::Data* SupportsUserData::GetUserData(const void* key) const {
  18. DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  19. // Avoid null keys; they are too vulnerable to collision.
  20. DCHECK(key);
  21. auto found = user_data_.find(key);
  22. if (found != user_data_.end())
  23. return found->second.get();
  24. return nullptr;
  25. }
  26. void SupportsUserData::SetUserData(const void* key,
  27. std::unique_ptr<Data> data) {
  28. DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  29. // Avoid null keys; they are too vulnerable to collision.
  30. DCHECK(key);
  31. if (data.get())
  32. user_data_[key] = std::move(data);
  33. else
  34. RemoveUserData(key);
  35. }
  36. void SupportsUserData::RemoveUserData(const void* key) {
  37. DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  38. user_data_.erase(key);
  39. }
  40. void SupportsUserData::DetachFromSequence() {
  41. DETACH_FROM_SEQUENCE(sequence_checker_);
  42. }
  43. void SupportsUserData::CloneDataFrom(const SupportsUserData& other) {
  44. for (const auto& data_pair : other.user_data_) {
  45. auto cloned_data = data_pair.second->Clone();
  46. if (cloned_data)
  47. SetUserData(data_pair.first, std::move(cloned_data));
  48. }
  49. }
  50. SupportsUserData::~SupportsUserData() {
  51. if (!user_data_.empty()) {
  52. DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  53. }
  54. DataMap local_user_data;
  55. user_data_.swap(local_user_data);
  56. // Now this->user_data_ is empty, and any destructors called transitively from
  57. // the destruction of |local_user_data| will see it that way instead of
  58. // examining a being-destroyed object.
  59. }
  60. void SupportsUserData::ClearAllUserData() {
  61. DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
  62. user_data_.clear();
  63. }
  64. } // namespace base