Merge commit '1dd2f4645226bd269f2407d5ed431acc3f66e7a6' as 'Sources/ASIO'

Sources/ASIO/asio/src/examples/cpp03/allocation/server.cpp

@@ -0,0 +1,285 @@
+//
+// 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 <cstdlib>
+#include <iostream>
+#include <boost/aligned_storage.hpp>
+#include <boost/array.hpp>
+#include <boost/bind.hpp>
+#include <boost/enable_shared_from_this.hpp>
+#include <boost/noncopyable.hpp>
+#include <boost/shared_ptr.hpp>
+#include "asio.hpp"
+
+using 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
+  : private boost::noncopyable
+{
+public:
+  handler_memory()
+    : in_use_(false)
+  {
+  }
+
+  void* allocate(std::size_t size)
+  {
+    if (!in_use_ && size < storage_.size)
+    {
+      in_use_ = true;
+      return storage_.address();
+    }
+    else
+    {
+      return ::operator new(size);
+    }
+  }
+
+  void deallocate(void* pointer)
+  {
+    if (pointer == storage_.address())
+    {
+      in_use_ = false;
+    }
+    else
+    {
+      ::operator delete(pointer);
+    }
+  }
+
+private:
+  // Storage space used for handler-based custom memory allocation.
+  boost::aligned_storage<1024> 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, plus rebind when
+// targeting C++03.
+template <typename T>
+class handler_allocator
+{
+public:
+  typedef T value_type;
+
+  explicit handler_allocator(handler_memory& mem)
+    : memory_(mem)
+  {
+  }
+
+  template <typename U>
+  handler_allocator(const handler_allocator<U>& other)
+    : memory_(other.memory_)
+  {
+  }
+
+  template <typename U>
+  struct rebind
+  {
+    typedef handler_allocator<U> other;
+  };
+
+  bool operator==(const handler_allocator& other) const
+  {
+    return &memory_ == &other.memory_;
+  }
+
+  bool operator!=(const handler_allocator& other) const
+  {
+    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:
+  // The underlying memory.
+  handler_memory& memory_;
+};
+
+// Wrapper class template for handler objects to allow handler memory
+// allocation to be customised. The allocator_type typedef 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:
+  typedef handler_allocator<Handler> allocator_type;
+
+  custom_alloc_handler(handler_memory& m, Handler h)
+    : memory_(m),
+      handler_(h)
+  {
+  }
+
+  allocator_type get_allocator() const
+  {
+    return allocator_type(memory_);
+  }
+
+  template <typename Arg1>
+  void operator()(Arg1 arg1)
+  {
+    handler_(arg1);
+  }
+
+  template <typename Arg1, typename Arg2>
+  void operator()(Arg1 arg1, Arg2 arg2)
+  {
+    handler_(arg1, arg2);
+  }
+
+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 boost::enable_shared_from_this<session>
+{
+public:
+  session(asio::io_context& io_context)
+    : socket_(io_context)
+  {
+  }
+
+  tcp::socket& socket()
+  {
+    return socket_;
+  }
+
+  void start()
+  {
+    socket_.async_read_some(asio::buffer(data_),
+        make_custom_alloc_handler(handler_memory_,
+          boost::bind(&session::handle_read,
+            shared_from_this(),
+            asio::placeholders::error,
+            asio::placeholders::bytes_transferred)));
+  }
+
+  void handle_read(const asio::error_code& error,
+      size_t bytes_transferred)
+  {
+    if (!error)
+    {
+      asio::async_write(socket_,
+          asio::buffer(data_, bytes_transferred),
+          make_custom_alloc_handler(handler_memory_,
+            boost::bind(&session::handle_write,
+              shared_from_this(),
+              asio::placeholders::error)));
+    }
+  }
+
+  void handle_write(const asio::error_code& error)
+  {
+    if (!error)
+    {
+      socket_.async_read_some(asio::buffer(data_),
+          make_custom_alloc_handler(handler_memory_,
+            boost::bind(&session::handle_read,
+              shared_from_this(),
+              asio::placeholders::error,
+              asio::placeholders::bytes_transferred)));
+    }
+  }
+
+private:
+  // The socket used to communicate with the client.
+  tcp::socket socket_;
+
+  // Buffer used to store data received from the client.
+  boost::array<char, 1024> data_;
+
+  // The memory to use for handler-based custom memory allocation.
+  handler_memory handler_memory_;
+};
+
+typedef boost::shared_ptr<session> session_ptr;
+
+class server
+{
+public:
+  server(asio::io_context& io_context, short port)
+    : io_context_(io_context),
+      acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
+  {
+    session_ptr new_session(new session(io_context_));
+    acceptor_.async_accept(new_session->socket(),
+        boost::bind(&server::handle_accept, this, new_session,
+          asio::placeholders::error));
+  }
+
+  void handle_accept(session_ptr new_session,
+      const asio::error_code& error)
+  {
+    if (!error)
+    {
+      new_session->start();
+    }
+
+    new_session.reset(new session(io_context_));
+    acceptor_.async_accept(new_session->socket(),
+        boost::bind(&server::handle_accept, this, new_session,
+          asio::placeholders::error));
+  }
+
+private:
+  asio::io_context& io_context_;
+  tcp::acceptor acceptor_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: server <port>\n";
+      return 1;
+    }
+
+    asio::io_context io_context;
+
+    using namespace std; // For atoi.
+    server s(io_context, atoi(argv[1]));
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}