86 lines
2.6 KiB
C++
86 lines
2.6 KiB
C++
/*
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* Copyright 2019 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <grpc++/grpc++.h>
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#include <atomic>
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#include <chrono>
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#include <utility>
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#include "blueberry/facade/common.pb.h"
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#include "common/blocking_queue.h"
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#include "os/log.h"
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namespace bluetooth {
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namespace grpc {
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template <typename T>
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class GrpcEventQueue {
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public:
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/**
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* Create a GrpcEventQueue that can be used to shuffle event from one thread to another
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* @param log_name
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*/
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explicit GrpcEventQueue(std::string log_name) : log_name_(std::move(log_name)){};
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/**
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* Run the event loop and blocks until client cancels the stream request
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* Event queue will be cleared before entering the loop. Hence, only events occurred after gRPC request will be
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* delivered to the user. Hence user is advised to run the loop before generating pending events.
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*
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* @param context client context
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* @param writer output writer
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* @return gRPC status
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*/
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::grpc::Status RunLoop(::grpc::ServerContext* context, ::grpc::ServerWriter<T>* writer) {
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using namespace std::chrono_literals;
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LOG_INFO("%s: Entering Loop", log_name_.c_str());
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while (!context->IsCancelled()) {
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// Wait for 100 ms so that cancellation can be caught in amortized 50 ms latency
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if (pending_events_.wait_to_take(100ms)) {
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LOG_INFO("%s: Got event from queue", log_name_.c_str());
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writer->Write(pending_events_.take());
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}
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}
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running_ = false;
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LOG_INFO("%s: Exited Loop", log_name_.c_str());
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return ::grpc::Status::OK;
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}
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/**
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* Called when there is an incoming event
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* @param event incoming event
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*/
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void OnIncomingEvent(T event) {
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if (!running_) {
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LOG_INFO("%s: Discarding an event while not running the loop", log_name_.c_str());
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return;
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}
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LOG_INFO("%s: Got event, enqueuing", log_name_.c_str());
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pending_events_.push(std::move(event));
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}
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private:
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std::string log_name_;
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std::atomic<bool> running_{true};
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common::BlockingQueue<T> pending_events_;
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};
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} // namespace grpc
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} // namespace bluetooth
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