server.cpp
6.29 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
//
// server.cpp
// ~~~~~~~~~~
//
// Copyright (c) 2003-2020 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/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;
}