// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you 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 <stdint.h>

#include <list>

#include <memory>

#include <mutex>

#include "util/countdown_latch.h"

#include "util/thread.h"

namespace doris {

class DataConsumer;

class DataConsumerGroup;

class Status;

class StreamLoadContext;

// DataConsumerPool saves all available data consumer

// to be reused

class DataConsumerPool {

public:

    DataConsumerPool() : _stop_background_threads_latch(1) {}

    ~DataConsumerPool() = default;

    void stop() {

        _stop_background_threads_latch.count_down();

        if (_clean_idle_consumer_thread) {

            _clean_idle_consumer_thread->join();

        }

    }

    // get a already initialized consumer from cache,

    // if not found in cache, create a new one.

    Status get_consumer(std::shared_ptr<StreamLoadContext> ctx, std::shared_ptr<DataConsumer>* ret);

    // get several consumers and put them into group

    Status get_consumer_grp(std::shared_ptr<StreamLoadContext> ctx,

                            std::shared_ptr<DataConsumerGroup>* ret);

    // return the consumer to the pool

    void return_consumer(std::shared_ptr<DataConsumer> consumer);

    // return the consumers in consumer group to the pool

    void return_consumers(DataConsumerGroup* grp);

    Status start_bg_worker();

private:

    void _clean_idle_consumer_bg();

private:

    std::mutex _lock;

    std::list<std::shared_ptr<DataConsumer>> _pool;

    CountDownLatch _stop_background_threads_latch;

    std::shared_ptr<Thread> _clean_idle_consumer_thread;

};

} // end namespace doris