ceph/src/boost/libs/asio/example/cpp11/local/connect_pair.cpp

   1 //
   2 // connect_pair.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 <array>
  12 #include <iostream>
  13 #include <string>
  14 #include <cctype>
  15 #include <boost/asio.hpp>
  16 #include <boost/thread/thread.hpp>
  17
  18 #if defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
  19
  20 using boost::asio::local::stream_protocol;
  21
  22 class uppercase_filter
  23 {
  24 public:
  25   uppercase_filter(stream_protocol::socket sock)
  26     : socket_(std::move(sock))
  27   {
  28     read();
  29   }
  30
  31 private:
  32   void read()
  33   {
  34     socket_.async_read_some(boost::asio::buffer(data_),
  35         [this](boost::system::error_code ec, std::size_t size)
  36         {
  37           if (!ec)
  38           {
  39             // Compute result.
  40             for (std::size_t i = 0; i < size; ++i)
  41               data_[i] = std::toupper(data_[i]);
  42
  43             // Send result.
  44             write(size);
  45           }
  46           else
  47           {
  48             throw boost::system::system_error(ec);
  49           }
  50         });
  51   }
  52
  53   void write(std::size_t size)
  54   {
  55     boost::asio::async_write(socket_, boost::asio::buffer(data_, size),
  56         [this](boost::system::error_code ec, std::size_t /*size*/)
  57         {
  58           if (!ec)
  59           {
  60             // Wait for request.
  61             read();
  62           }
  63           else
  64           {
  65             throw boost::system::system_error(ec);
  66           }
  67         });
  68   }
  69
  70   stream_protocol::socket socket_;
  71   std::array<char, 512> data_;
  72 };
  73
  74 int main()
  75 {
  76   try
  77   {
  78     boost::asio::io_context io_context;
  79
  80     // Create a connected pair and pass one end to a filter.
  81     stream_protocol::socket socket(io_context);
  82     stream_protocol::socket filter_socket(io_context);
  83     boost::asio::local::connect_pair(socket, filter_socket);
  84     uppercase_filter filter(std::move(filter_socket));
  85
  86     // The io_context runs in a background thread to perform filtering.
  87     boost::thread thread(
  88         [&io_context]()
  89         {
  90           try
  91           {
  92             io_context.run();
  93           }
  94           catch (std::exception& e)
  95           {
  96             std::cerr << "Exception in thread: " << e.what() << "\n";
  97             std::exit(1);
  98           }
  99         });
 100
 101     for (;;)
 102     {
 103       // Collect request from user.
 104       std::cout << "Enter a string: ";
 105       std::string request;
 106       std::getline(std::cin, request);
 107
 108       // Send request to filter.
 109       boost::asio::write(socket, boost::asio::buffer(request));
 110
 111       // Wait for reply from filter.
 112       std::vector<char> reply(request.size());
 113       boost::asio::read(socket, boost::asio::buffer(reply));
 114
 115       // Show reply to user.
 116       std::cout << "Result: ";
 117       std::cout.write(&reply[0], request.size());
 118       std::cout << std::endl;
 119     }
 120   }
 121   catch (std::exception& e)
 122   {
 123     std::cerr << "Exception: " << e.what() << "\n";
 124     std::exit(1);
 125   }
 126 }
 127
 128 #else // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)
 129 # error Local sockets not available on this platform.
 130 #endif // defined(BOOST_ASIO_HAS_LOCAL_SOCKETS)