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

   1 //
   2 // reference_counted.cpp
   3 // ~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2017 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
  17 using boost::asio::ip::tcp;
  18
  19 // A reference-counted non-modifiable buffer class.
  20 class shared_const_buffer
  21 {
  22 public:
  23   // Construct from a std::string.
  24   explicit shared_const_buffer(const std::string& data)
  25     : data_(new std::vector<char>(data.begin(), data.end())),
  26       buffer_(boost::asio::buffer(*data_))
  27   {
  28   }
  29
  30   // Implement the ConstBufferSequence requirements.
  31   typedef boost::asio::const_buffer value_type;
  32   typedef const boost::asio::const_buffer* const_iterator;
  33   const boost::asio::const_buffer* begin() const { return &buffer_; }
  34   const boost::asio::const_buffer* end() const { return &buffer_ + 1; }
  35
  36 private:
  37   std::shared_ptr<std::vector<char> > data_;
  38   boost::asio::const_buffer buffer_;
  39 };
  40
  41 class session
  42   : public std::enable_shared_from_this<session>
  43 {
  44 public:
  45   session(tcp::socket socket)
  46     : socket_(std::move(socket))
  47   {
  48   }
  49
  50   void start()
  51   {
  52     do_write();
  53   }
  54
  55 private:
  56   void do_write()
  57   {
  58     std::time_t now = std::time(0);
  59     shared_const_buffer buffer(std::ctime(&now));
  60
  61     auto self(shared_from_this());
  62     boost::asio::async_write(socket_, buffer,
  63         [this, self](boost::system::error_code /*ec*/, std::size_t /*length*/)
  64         {
  65         });
  66   }
  67
  68   // The socket used to communicate with the client.
  69   tcp::socket socket_;
  70 };
  71
  72 class server
  73 {
  74 public:
  75   server(boost::asio::io_context& io_context, short port)
  76     : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
  77   {
  78     do_accept();
  79   }
  80
  81 private:
  82   void do_accept()
  83   {
  84     acceptor_.async_accept(
  85         [this](boost::system::error_code ec, tcp::socket socket)
  86         {
  87           if (!ec)
  88           {
  89             std::make_shared<session>(std::move(socket))->start();
  90           }
  91
  92           do_accept();
  93         });
  94   }
  95
  96   tcp::acceptor acceptor_;
  97 };
  98
  99 int main(int argc, char* argv[])
 100 {
 101   try
 102   {
 103     if (argc != 2)
 104     {
 105       std::cerr << "Usage: reference_counted <port>\n";
 106       return 1;
 107     }
 108
 109     boost::asio::io_context io_context;
 110
 111     server s(io_context, std::atoi(argv[1]));
 112
 113     io_context.run();
 114   }
 115   catch (std::exception& e)
 116   {
 117     std::cerr << "Exception: " << e.what() << "\n";
 118   }
 119
 120   return 0;
 121 }