123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255 |
- //
- // server.cpp
- // ~~~~~~~~~~
- //
- // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
- //
- // Distributed under the Boost Software License, Version 1.0. (See accompanying
- // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- //
- #include <array>
- #include <cstdlib>
- #include <iostream>
- #include <memory>
- #include <type_traits>
- #include <utility>
- #include <boost/asio.hpp>
- using boost::asio::ip::tcp;
- // Class to manage the memory to be used for handler-based custom allocation.
- // It contains a single block of memory which may be returned for allocation
- // requests. If the memory is in use when an allocation request is made, the
- // allocator delegates allocation to the global heap.
- class handler_memory
- {
- public:
- handler_memory()
- : in_use_(false)
- {
- }
- handler_memory(const handler_memory&) = delete;
- handler_memory& operator=(const handler_memory&) = delete;
- void* allocate(std::size_t size)
- {
- if (!in_use_ && size < sizeof(storage_))
- {
- in_use_ = true;
- return &storage_;
- }
- else
- {
- return ::operator new(size);
- }
- }
- void deallocate(void* pointer)
- {
- if (pointer == &storage_)
- {
- in_use_ = false;
- }
- else
- {
- ::operator delete(pointer);
- }
- }
- private:
- // Storage space used for handler-based custom memory allocation.
- typename std::aligned_storage<1024>::type storage_;
- // Whether the handler-based custom allocation storage has been used.
- bool in_use_;
- };
- // The allocator to be associated with the handler objects. This allocator only
- // needs to satisfy the C++11 minimal allocator requirements.
- template <typename T>
- class handler_allocator
- {
- public:
- using value_type = T;
- explicit handler_allocator(handler_memory& mem)
- : memory_(mem)
- {
- }
- template <typename U>
- handler_allocator(const handler_allocator<U>& other) noexcept
- : memory_(other.memory_)
- {
- }
- bool operator==(const handler_allocator& other) const noexcept
- {
- return &memory_ == &other.memory_;
- }
- bool operator!=(const handler_allocator& other) const noexcept
- {
- return &memory_ != &other.memory_;
- }
- T* allocate(std::size_t n) const
- {
- return static_cast<T*>(memory_.allocate(sizeof(T) * n));
- }
- void deallocate(T* p, std::size_t /*n*/) const
- {
- return memory_.deallocate(p);
- }
- private:
- template <typename> friend class handler_allocator;
- // The underlying memory.
- handler_memory& memory_;
- };
- // Wrapper class template for handler objects to allow handler memory
- // allocation to be customised. The allocator_type type and get_allocator()
- // member function are used by the asynchronous operations to obtain the
- // allocator. Calls to operator() are forwarded to the encapsulated handler.
- template <typename Handler>
- class custom_alloc_handler
- {
- public:
- using allocator_type = handler_allocator<Handler>;
- custom_alloc_handler(handler_memory& m, Handler h)
- : memory_(m),
- handler_(h)
- {
- }
- allocator_type get_allocator() const noexcept
- {
- return allocator_type(memory_);
- }
- template <typename ...Args>
- void operator()(Args&&... args)
- {
- handler_(std::forward<Args>(args)...);
- }
- private:
- handler_memory& memory_;
- Handler handler_;
- };
- // Helper function to wrap a handler object to add custom allocation.
- template <typename Handler>
- inline custom_alloc_handler<Handler> make_custom_alloc_handler(
- handler_memory& m, Handler h)
- {
- return custom_alloc_handler<Handler>(m, h);
- }
- class session
- : public std::enable_shared_from_this<session>
- {
- public:
- session(tcp::socket socket)
- : socket_(std::move(socket))
- {
- }
- void start()
- {
- do_read();
- }
- private:
- void do_read()
- {
- auto self(shared_from_this());
- socket_.async_read_some(boost::asio::buffer(data_),
- make_custom_alloc_handler(handler_memory_,
- [this, self](boost::system::error_code ec, std::size_t length)
- {
- if (!ec)
- {
- do_write(length);
- }
- }));
- }
- void do_write(std::size_t length)
- {
- auto self(shared_from_this());
- boost::asio::async_write(socket_, boost::asio::buffer(data_, length),
- make_custom_alloc_handler(handler_memory_,
- [this, self](boost::system::error_code ec, std::size_t /*length*/)
- {
- if (!ec)
- {
- do_read();
- }
- }));
- }
- // The socket used to communicate with the client.
- tcp::socket socket_;
- // Buffer used to store data received from the client.
- std::array<char, 1024> data_;
- // The memory to use for handler-based custom memory allocation.
- handler_memory handler_memory_;
- };
- class server
- {
- public:
- server(boost::asio::io_context& io_context, short port)
- : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
- {
- do_accept();
- }
- private:
- void do_accept()
- {
- acceptor_.async_accept(
- [this](boost::system::error_code ec, tcp::socket socket)
- {
- if (!ec)
- {
- std::make_shared<session>(std::move(socket))->start();
- }
- do_accept();
- });
- }
- tcp::acceptor acceptor_;
- };
- int main(int argc, char* argv[])
- {
- try
- {
- if (argc != 2)
- {
- std::cerr << "Usage: server <port>\n";
- return 1;
- }
- boost::asio::io_context io_context;
- server s(io_context, std::atoi(argv[1]));
- io_context.run();
- }
- catch (std::exception& e)
- {
- std::cerr << "Exception: " << e.what() << "\n";
- }
- return 0;
- }
|