| /* |
| * Copyright 2019 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. |
| */ |
| |
| #pragma once |
| |
| #include <grpc++/grpc++.h> |
| |
| #include <atomic> |
| #include <chrono> |
| #include <utility> |
| |
| #include "common/blocking_queue.h" |
| #include "facade/common.pb.h" |
| #include "os/log.h" |
| |
| namespace bluetooth { |
| namespace grpc { |
| |
| template <typename T> |
| class GrpcEventQueue { |
| public: |
| /** |
| * Create a GrpcEventQueue that can be used to shuffle event from one thread to another |
| * @param log_name |
| */ |
| explicit GrpcEventQueue(std::string log_name) : log_name_(std::move(log_name)){}; |
| |
| /** |
| * Run the event loop and blocks until client cancels the stream request |
| * Event queue will be cleared before entering the loop. Hence, only events occurred after gRPC request will be |
| * delivered to the user. Hence user is advised to run the loop before generating pending events. |
| * |
| * @param context client context |
| * @param writer output writer |
| * @return gRPC status |
| */ |
| ::grpc::Status RunLoop(::grpc::ServerContext* context, ::grpc::ServerWriter<T>* writer) { |
| using namespace std::chrono_literals; |
| LOG_INFO("%s: Entering Loop", log_name_.c_str()); |
| pending_events_.clear(); |
| running_ = true; |
| while (!context->IsCancelled()) { |
| // Wait for 500 ms so that cancellation can be caught in amortized 250 ms latency |
| if (pending_events_.wait_to_take(500ms)) { |
| LOG_INFO("%s: Got event after queue", log_name_.c_str()); |
| writer->Write(pending_events_.take()); |
| } |
| } |
| running_ = false; |
| LOG_INFO("%s: Exited Loop", log_name_.c_str()); |
| return ::grpc::Status::OK; |
| } |
| |
| /** |
| * Called when there is an incoming event |
| * @param event incoming event |
| */ |
| void OnIncomingEvent(T event) { |
| if (!running_) { |
| LOG_INFO("%s: Discarding an event while not running the loop", log_name_.c_str()); |
| return; |
| } |
| LOG_INFO("%s: Got event before queue", log_name_.c_str()); |
| pending_events_.push(std::move(event)); |
| } |
| |
| private: |
| std::string log_name_; |
| std::atomic<bool> running_ = false; |
| common::BlockingQueue<T> pending_events_; |
| }; |
| |
| } // namespace grpc |
| } // namespace bluetooth |