ceph/src/boost/libs/asio/example/cpp11/buffers/reference_counted.cpp

   1 //
   2 // reference_counted.cpp
   3 // ~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #include <boost/asio.hpp>
  12 #include <iostream>
  13 #include <memory>
  14 #include <utility>
  15 #include <vector>
  16 #include <ctime>
  17
  18 using boost::asio::ip::tcp;
  19
  20 // A reference-counted non-modifiable buffer class.
  21 class shared_const_buffer
  22 {
  23 public:
  24   // Construct from a std::string.
  25   explicit shared_const_buffer(const std::string& data)
  26     : data_(new std::vector<char>(data.begin(), data.end())),
  27       buffer_(boost::asio::buffer(*data_))
  28   {
  29   }
  30
  31   // Implement the ConstBufferSequence requirements.
  32   typedef boost::asio::const_buffer value_type;
  33   typedef const boost::asio::const_buffer* const_iterator;
  34   const boost::asio::const_buffer* begin() const { return &buffer_; }
  35   const boost::asio::const_buffer* end() const { return &buffer_ + 1; }
  36
  37 private:
  38   std::shared_ptr<std::vector<char> > data_;
  39   boost::asio::const_buffer buffer_;
  40 };
  41
  42 class session
  43   : public std::enable_shared_from_this<session>
  44 {
  45 public:
  46   session(tcp::socket socket)
  47     : socket_(std::move(socket))
  48   {
  49   }
  50
  51   void start()
  52   {
  53     do_write();
  54   }
  55
  56 private:
  57   void do_write()
  58   {
  59     std::time_t now = std::time(0);
  60     shared_const_buffer buffer(std::ctime(&now));
  61
  62     auto self(shared_from_this());
  63     boost::asio::async_write(socket_, buffer,
  64         [self](boost::system::error_code /*ec*/, std::size_t /*length*/)
  65         {
  66         });
  67   }
  68
  69   // The socket used to communicate with the client.
  70   tcp::socket socket_;
  71 };
  72
  73 class server
  74 {
  75 public:
  76   server(boost::asio::io_context& io_context, short port)
  77     : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
  78   {
  79     do_accept();
  80   }
  81
  82 private:
  83   void do_accept()
  84   {
  85     acceptor_.async_accept(
  86         [this](boost::system::error_code ec, tcp::socket socket)
  87         {
  88           if (!ec)
  89           {
  90             std::make_shared<session>(std::move(socket))->start();
  91           }
  92
  93           do_accept();
  94         });
  95   }
  96
  97   tcp::acceptor acceptor_;
  98 };
  99
 100 int main(int argc, char* argv[])
 101 {
 102   try
 103   {
 104     if (argc != 2)
 105     {
 106       std::cerr << "Usage: reference_counted <port>\n";
 107       return 1;
 108     }
 109
 110     boost::asio::io_context io_context;
 111
 112     server s(io_context, std::atoi(argv[1]));
 113
 114     io_context.run();
 115   }
 116   catch (std::exception& e)
 117   {
 118     std::cerr << "Exception: " << e.what() << "\n";
 119   }
 120
 121   return 0;
 122 }