| // Copyright 2018 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. |
| |
| #ifndef SERVICES_AUDIO_GROUP_COORDINATOR_IMPL_H_ |
| #define SERVICES_AUDIO_GROUP_COORDINATOR_IMPL_H_ |
| |
| #include "base/compiler_specific.h" |
| #include "base/no_destructor.h" |
| |
| #if DCHECK_IS_ON() |
| #define DCHECK_INCREMENT_MUTATION_COUNT() ++mutation_count_ |
| #define DCHECK_REMEMBER_CURRENT_MUTATION_COUNT() \ |
| const auto change_number = mutation_count_ |
| #define DCHECK_MUTATION_COUNT_UNCHANGED() \ |
| DCHECK_EQ(mutation_count_, change_number) |
| #else |
| #define DCHECK_INCREMENT_MUTATION_COUNT() |
| #define DCHECK_REMEMBER_CURRENT_MUTATION_COUNT() |
| #define DCHECK_MUTATION_COUNT_UNCHANGED() |
| #endif |
| |
| namespace audio { |
| |
| template <typename Member> |
| GroupCoordinator<Member>::GroupCoordinator() { |
| DETACH_FROM_SEQUENCE(sequence_checker_); |
| } |
| |
| template <typename Member> |
| GroupCoordinator<Member>::~GroupCoordinator() { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| DCHECK(groups_.empty()); |
| } |
| |
| template <typename Member> |
| void GroupCoordinator<Member>::RegisterMember( |
| const base::UnguessableToken& group_id, |
| Member* member) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| DCHECK(member); |
| |
| const auto it = FindGroup(group_id); |
| std::vector<Member*>& members = it->second.members; |
| DCHECK(!base::ContainsValue(members, member)); |
| members.push_back(member); |
| DCHECK_INCREMENT_MUTATION_COUNT(); |
| DCHECK_REMEMBER_CURRENT_MUTATION_COUNT(); |
| |
| for (Observer* observer : it->second.observers) { |
| observer->OnMemberJoinedGroup(member); |
| DCHECK_MUTATION_COUNT_UNCHANGED(); |
| } |
| } |
| |
| template <typename Member> |
| void GroupCoordinator<Member>::UnregisterMember( |
| const base::UnguessableToken& group_id, |
| Member* member) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| DCHECK(member); |
| |
| const auto group_it = FindGroup(group_id); |
| std::vector<Member*>& members = group_it->second.members; |
| const auto member_it = std::find(members.begin(), members.end(), member); |
| DCHECK(member_it != members.end()); |
| members.erase(member_it); |
| DCHECK_INCREMENT_MUTATION_COUNT(); |
| DCHECK_REMEMBER_CURRENT_MUTATION_COUNT(); |
| |
| for (Observer* observer : group_it->second.observers) { |
| observer->OnMemberLeftGroup(member); |
| DCHECK_MUTATION_COUNT_UNCHANGED(); |
| } |
| |
| MaybePruneGroupMapEntry(group_it); |
| } |
| |
| template <typename Member> |
| void GroupCoordinator<Member>::AddObserver( |
| const base::UnguessableToken& group_id, |
| Observer* observer) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| DCHECK(observer); |
| |
| std::vector<Observer*>& observers = FindGroup(group_id)->second.observers; |
| DCHECK(!base::ContainsValue(observers, observer)); |
| observers.push_back(observer); |
| DCHECK_INCREMENT_MUTATION_COUNT(); |
| } |
| |
| template <typename Member> |
| void GroupCoordinator<Member>::RemoveObserver( |
| const base::UnguessableToken& group_id, |
| Observer* observer) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| DCHECK(observer); |
| |
| const auto group_it = FindGroup(group_id); |
| std::vector<Observer*>& observers = group_it->second.observers; |
| const auto it = std::find(observers.begin(), observers.end(), observer); |
| DCHECK(it != observers.end()); |
| observers.erase(it); |
| DCHECK_INCREMENT_MUTATION_COUNT(); |
| |
| MaybePruneGroupMapEntry(group_it); |
| } |
| |
| template <typename Member> |
| void GroupCoordinator<Member>::ForEachMemberInGroup( |
| const base::UnguessableToken& group_id, |
| base::RepeatingCallback<void(Member*)> callback) const { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| DCHECK_REMEMBER_CURRENT_MUTATION_COUNT(); |
| for (Member* member : this->GetCurrentMembersUnsafe(group_id)) { |
| callback.Run(member); |
| // Note: If this fails, then not only is there a re-entrancy problem, but |
| // also the iterator being used by this for-loop is no longer valid! |
| DCHECK_MUTATION_COUNT_UNCHANGED(); |
| } |
| } |
| |
| template <typename Member> |
| const std::vector<Member*>& GroupCoordinator<Member>::GetCurrentMembersUnsafe( |
| const base::UnguessableToken& group_id) const { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| for (const auto& entry : groups_) { |
| if (entry.first == group_id) { |
| return entry.second.members; |
| } |
| } |
| |
| static const base::NoDestructor<std::vector<Member*>> empty_set; |
| return *empty_set; |
| } |
| |
| template <typename Member> |
| typename GroupCoordinator<Member>::GroupMap::iterator |
| GroupCoordinator<Member>::FindGroup(const base::UnguessableToken& group_id) { |
| for (auto it = groups_.begin(); it != groups_.end(); ++it) { |
| if (it->first == group_id) { |
| return it; |
| } |
| } |
| |
| // Group does not exist. Create a new entry. |
| groups_.emplace_back(); |
| const auto new_it = groups_.end() - 1; |
| new_it->first = group_id; |
| DCHECK_INCREMENT_MUTATION_COUNT(); |
| return new_it; |
| } |
| |
| template <typename Member> |
| void GroupCoordinator<Member>::MaybePruneGroupMapEntry( |
| typename GroupMap::iterator it) { |
| if (it->second.members.empty() && it->second.observers.empty()) { |
| groups_.erase(it); |
| DCHECK_INCREMENT_MUTATION_COUNT(); |
| } |
| } |
| |
| template <typename Member> |
| GroupCoordinator<Member>::Observer::~Observer() = default; |
| |
| template <typename Member> |
| GroupCoordinator<Member>::Group::Group() = default; |
| template <typename Member> |
| GroupCoordinator<Member>::Group::~Group() = default; |
| template <typename Member> |
| GroupCoordinator<Member>::Group::Group( |
| GroupCoordinator<Member>::Group&& other) = default; |
| template <typename Member> |
| typename GroupCoordinator<Member>::Group& GroupCoordinator<Member>::Group:: |
| operator=(GroupCoordinator::Group&& other) = default; |
| |
| } // namespace audio |
| |
| #if DCHECK_IS_ON() |
| #undef DCHECK_INCREMENT_MUTATION_COUNT |
| #undef DCHECK_REMEMBER_CURRENT_MUTATION_COUNT |
| #undef DCHECK_MUTATION_COUNT_UNCHANGED |
| #endif |
| |
| #endif // SERVICES_AUDIO_GROUP_COORDINATOR_IMPL_H_ |