| // Copyright 2017 Google Inc. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef COBALT_DOM_MUTATION_OBSERVER_TASK_MANAGER_H_ |
| #define COBALT_DOM_MUTATION_OBSERVER_TASK_MANAGER_H_ |
| |
| #include <utility> |
| |
| #include "base/hash_tables.h" |
| #include "base/threading/thread_checker.h" |
| #include "cobalt/script/global_environment.h" |
| #include "cobalt/script/tracer.h" |
| |
| namespace cobalt { |
| namespace dom { |
| |
| class MutationObserver; |
| |
| // The Mutation observer spec describes a sequence of steps to "queue a mutation |
| // observer compound microtask" and "notify mutation observers". These steps |
| // are implemented in this helper class, which must outlive all |
| // MutationObserver instances. |
| // The spec expects an EventLoop implementation, which Cobalt does not currently |
| // have. |
| // https://www.w3.org/TR/dom/#mutation-observers |
| class MutationObserverTaskManager : public script::Traceable { |
| public: |
| MutationObserverTaskManager() : task_posted_(false) {} |
| |
| void RegisterAsTracingRoot(script::GlobalEnvironment* global_environment) { |
| // Note that we only add ourselves, and never remove ourselves, as we will |
| // actually outlive the web module. |
| global_environment->AddRoot(this); |
| } |
| |
| // These should be called in the constructor/destructor of the |
| // MutationObserver. |
| void OnMutationObserverCreated(MutationObserver* observer); |
| void OnMutationObserverDestroyed(MutationObserver* observer); |
| |
| // Post a task to notify mutation observers, if one is not already posted. |
| void QueueMutationObserverMicrotask(); |
| |
| void TraceMembers(script::Tracer* tracer) override; |
| |
| private: |
| typedef base::hash_set<MutationObserver*> MutationObserverSet; |
| |
| // Notify all mutation observers. |
| void NotifyMutationObservers(); |
| |
| base::ThreadChecker thread_checker_; |
| MutationObserverSet observers_; |
| bool task_posted_; |
| }; |
| |
| } // namespace dom |
| } // namespace cobalt |
| |
| #endif // COBALT_DOM_MUTATION_OBSERVER_TASK_MANAGER_H_ |