DISocket.h

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// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
// All rights not expressly granted are reserved.
//
// This software is distributed under the terms of the GNU General Public
// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
//
// In applying this license CERN does not waive the privileges and immunities
// granted to it by virtue of its status as an Intergovernmental Organization
// or submit itself to any jurisdiction.
#ifndef O2_DISOCKET_HPP
#define O2_DISOCKET_HPP
 
#include <cstring>
#include "Framework/Traits.h"
#include "boost/asio.hpp"
#include "boost/endian/conversion.hpp"
#include <sstream>
 
struct DIMessage {
  struct __attribute__((packed)) Header {
    enum class Type : uint32_t {
      INVALID = 0,
      DATA = 1,
      DEVICE_ON = 2,
      DEVICE_OFF = 3,
      INSPECT_ON = 4,
      INSPECT_OFF = 5,
      TERMINATE = 6
    };
 
    Header(Type type, uint64_t payloadSize) : typeLE(boost::endian::native_to_little(static_cast<uint32_t>(type))), payloadSizeLE(boost::endian::native_to_little(payloadSize)) {}
    Header(Type type) : Header(type, 0) {}
    Header() : Header(Type::INVALID, 0) {}
 
    Type type() const;
    uint64_t payloadSize() const;
 
   private:
    uint32_t typeLE;
    uint64_t payloadSizeLE;
  };
 
  template <typename T>
  DIMessage(Header::Type type, const T& payload)
  {
    uint64_t payloadSize = 0;
    if constexpr (std::is_base_of_v<std::string, T>) {
      payloadSize = payload.size();
      this->payload = new char[payloadSize];
      std::memcpy(this->payload, payload.data(), payloadSize);
    } else if constexpr (std::is_integral_v<T>) {
      payloadSize = sizeof(T);
      payload = boost::endian::native_to_little(payload);
      this->payload = new char[payloadSize];
      std::memcpy(this->payload, &payload, payloadSize);
    } else {
      static_assert(o2::framework::always_static_assert_v<T>, "DISocket: Cannot create message of this type.");
    }
 
    header = Header{type, payloadSize};
  }
  DIMessage() : header(Header::Type::INVALID), payload(nullptr) {}
 
  DIMessage(const DIMessage& other) noexcept;
  DIMessage& operator=(const DIMessage& other) noexcept;
 
  DIMessage(DIMessage&& other) noexcept;
  DIMessage& operator=(DIMessage&& other) noexcept;
 
  ~DIMessage();
 
  template <typename T>
  T get() const
  {
    if constexpr (std::is_same_v<std::string, T>) {
      return std::string{payload, header.payloadSize()};
    } else if constexpr (std::is_integral_v<T>) {
      return boost::endian::little_to_native(*((T*)payload));
    } else {
      static_assert(o2::framework::always_static_assert_v<T>, "DISocket: Cannot create object of this type.");
    }
  }
 
  Header header;
  char* payload;
};
 
class DISocket
{
 public:
  DISocket(const std::string& address, int port);
  ~DISocket();
 
  bool isMessageAvailable();
  void send(const DIMessage& message);
  DIMessage receive();
 
 private:
  boost::asio::io_context ioContext;
  boost::asio::ip::tcp::socket socket;
};
 
#endif // O2_DISOCKET_HPP