| /* |
| * Copyright (C) 2016 The Android Open Source Project |
| * |
| * 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 CHRE_EVENT_REF_QUEUE_H |
| #define CHRE_EVENT_REF_QUEUE_H |
| |
| #include "chre/core/event.h" |
| #include "chre/util/array_queue.h" |
| |
| namespace chre { |
| |
| /** |
| * A non-thread-safe, non-blocking wrapper around ArrayQueue that stores Event* |
| * and manages the Event reference counter. |
| * TODO: make this a template specialization? Or rework the ref count design? |
| */ |
| class EventRefQueue { |
| public: |
| ~EventRefQueue(); |
| |
| /** |
| * @return true if there are no events in the queue |
| */ |
| bool empty() const; |
| |
| /** |
| * Adds an event to the queue, and increments its reference counter |
| * |
| * @param event The event to add |
| * @return true on success |
| */ |
| bool push(Event *event); |
| |
| /** |
| * Removes the oldest event from the queue, and decrements its reference |
| * counter. Does not trigger freeing of the event if the reference count |
| * reaches 0 as a result of this function call. The queue must be non-empty as |
| * a precondition to calling this function, or undefined behavior will result. |
| * |
| * @return Pointer to the next event in the queue |
| */ |
| Event *pop(); |
| |
| private: |
| //! The maximum number of events that can be outstanding for an app. |
| static constexpr size_t kMaxPendingEvents = 16; |
| |
| //! The queue of incoming events. |
| ArrayQueue<Event *, kMaxPendingEvents> mQueue; |
| }; |
| |
| } // namespace chre |
| |
| #endif // CHRE_EVENT_REF_QUEUE_H |