| /* |
| * Copyright (C) 2018 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 android_hardware_automotive_vehicle_V2_0_impl_GeneratorHub_H_ |
| #define android_hardware_automotive_vehicle_V2_0_impl_GeneratorHub_H_ |
| |
| #include <atomic> |
| #include <chrono> |
| #include <condition_variable> |
| #include <iostream> |
| #include <queue> |
| #include <thread> |
| #include <unordered_map> |
| |
| #include "FakeValueGenerator.h" |
| |
| namespace android { |
| namespace hardware { |
| namespace automotive { |
| namespace vehicle { |
| namespace V2_0 { |
| |
| namespace impl { |
| |
| /** |
| * This is the scheduler for all VHAL event generators. It manages all generators and uses priority |
| * queue to maintain generated events ordered by timestamp. The scheduler uses a single thread to |
| * keep querying and updating the event queue to make sure events from all generators are produced |
| * in order. |
| */ |
| class GeneratorHub { |
| private: |
| struct VhalEvent { |
| int32_t cookie; // Cookie is used to find the associated generator. |
| VehiclePropValue val; |
| }; |
| // Comparator used by priority queue to keep track of soonest event. |
| struct GreaterByTime { |
| bool operator()(const VhalEvent& lhs, const VhalEvent& rhs) const { |
| return lhs.val.timestamp > rhs.val.timestamp; |
| } |
| }; |
| |
| using OnHalEvent = std::function<void(const VehiclePropValue& event)>; |
| |
| public: |
| GeneratorHub(const OnHalEvent& onHalEvent); |
| ~GeneratorHub() = default; |
| |
| /** |
| * Register a new generator. The generator will be discarded if it could not produce next event. |
| * The existing generator will be overridden if it has the same cookie. |
| */ |
| void registerGenerator(int32_t cookie, FakeValueGeneratorPtr generator); |
| |
| void unregisterGenerator(int32_t cookie); |
| |
| private: |
| /** |
| * Main loop of the single thread to producing event and updating event queue. |
| */ |
| void run(); |
| |
| bool hasNext(int32_t cookie); |
| |
| private: |
| std::priority_queue<VhalEvent, std::vector<VhalEvent>, GreaterByTime> mEventQueue; |
| std::unordered_map<int32_t, FakeValueGeneratorPtr> mGenerators; |
| OnHalEvent mOnHalEvent; |
| |
| mutable std::mutex mLock; |
| std::condition_variable mCond; |
| std::thread mThread; |
| }; |
| |
| } // namespace impl |
| |
| } // namespace V2_0 |
| } // namespace vehicle |
| } // namespace automotive |
| } // namespace hardware |
| } // namespace android |
| |
| #endif // android_hardware_automotive_vehicle_V2_0_impl_GeneratorHub_H_ |