buffer.h

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/****************************************************************************
 *
 * fkie_message_filters
 * Copyright © 2018-2020 Fraunhofer FKIE
 * Author: Timo Röhling
 *
 * 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 INCLUDE_FKIE_MESSAGE_FILTERS_BUFFER_H_
#define INCLUDE_FKIE_MESSAGE_FILTERS_BUFFER_H_


#include "filter.h"
#include <boost/circular_buffer.hpp>
#include <tuple>
#include <mutex>
#include <condition_variable>
#include <ros/callback_queue_interface.h>
#include <ros/node_handle.h>


namespace fkie_message_filters
{

enum class BufferPolicy
{
    Discard,
    Queue,
    Passthru
};

template<class... Inputs>
class Buffer : public Filter<IO<Inputs...>, IO<Inputs...>>
{
public:
    Buffer (const ros::NodeHandle& nh, std::size_t max_queue_size) noexcept;
    Buffer (BufferPolicy policy = BufferPolicy::Discard, std::size_t max_queue_size = 1, ros::CallbackQueueInterface* cbq = nullptr) noexcept;
    virtual ~Buffer();
    void set_policy (BufferPolicy policy, std::size_t max_queue_size = 0);
    void set_callback_queue(ros::CallbackQueueInterface* cbq) noexcept;
    bool has_some() const noexcept;
    bool wait() noexcept;
    template<class Rep, class Period>
    bool wait_for(const std::chrono::duration<Rep, Period>& timeout) noexcept;
    bool process_one();
    template<class Rep, class Period>
    bool process_one(const std::chrono::duration<Rep, Period>& timeout);
    void spin_once();
    void spin();
    void reset() noexcept override;
protected:
    virtual void receive(const Inputs&... in) override;
private:
    struct Impl;
    class RosCB;
    using QueueElement = std::tuple<Inputs...>;
    void process_some(std::unique_lock<std::mutex>&);
    void send_queue_element(const QueueElement& e);
    std::shared_ptr<Impl> impl_;
    ros::CallbackQueueInterface* cbq_;
};

template<class... Inputs>
class Buffer<IO<Inputs...>> : public Buffer<Inputs...> {};

} // namespace fkie_message_filters

#include "buffer_impl.h"

#endif /* INCLUDE_FKIE_MESSAGE_FILTERS_BUFFER_H_ */