1//
2// buffered_write_stream.hpp
3// ~~~~~~~~~~~~~~~~~~~~~~~~~
4//
5// Copyright (c) 2003-2015 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#ifndef BOOST_ASIO_BUFFERED_WRITE_STREAM_HPP
12#define BOOST_ASIO_BUFFERED_WRITE_STREAM_HPP
13
14#if defined(_MSC_VER) && (_MSC_VER >= 1200)
15# pragma once
16#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17
18#include <boost/asio/detail/config.hpp>
19#include <cstddef>
20#include <boost/asio/buffered_write_stream_fwd.hpp>
21#include <boost/asio/buffer.hpp>
22#include <boost/asio/completion_condition.hpp>
23#include <boost/asio/detail/bind_handler.hpp>
24#include <boost/asio/detail/buffered_stream_storage.hpp>
25#include <boost/asio/detail/noncopyable.hpp>
26#include <boost/asio/detail/type_traits.hpp>
27#include <boost/asio/error.hpp>
28#include <boost/asio/io_service.hpp>
29#include <boost/asio/write.hpp>
30
31#include <boost/asio/detail/push_options.hpp>
32
33namespace boost {
34namespace asio {
35
36/// Adds buffering to the write-related operations of a stream.
37/**
38 * The buffered_write_stream class template can be used to add buffering to the
39 * synchronous and asynchronous write operations of a stream.
40 *
41 * @par Thread Safety
42 * @e Distinct @e objects: Safe.@n
43 * @e Shared @e objects: Unsafe.
44 *
45 * @par Concepts:
46 * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
47 */
48template <typename Stream>
49class buffered_write_stream
50 : private noncopyable
51{
52public:
53 /// The type of the next layer.
54 typedef typename remove_reference<Stream>::type next_layer_type;
55
56 /// The type of the lowest layer.
57 typedef typename next_layer_type::lowest_layer_type lowest_layer_type;
58
59#if defined(GENERATING_DOCUMENTATION)
60 /// The default buffer size.
61 static const std::size_t default_buffer_size = implementation_defined;
62#else
63 BOOST_ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024);
64#endif
65
66 /// Construct, passing the specified argument to initialise the next layer.
67 template <typename Arg>
68 explicit buffered_write_stream(Arg& a)
69 : next_layer_(a),
70 storage_(default_buffer_size)
71 {
72 }
73
74 /// Construct, passing the specified argument to initialise the next layer.
75 template <typename Arg>
76 buffered_write_stream(Arg& a, std::size_t buffer_size)
77 : next_layer_(a),
78 storage_(buffer_size)
79 {
80 }
81
82 /// Get a reference to the next layer.
83 next_layer_type& next_layer()
84 {
85 return next_layer_;
86 }
87
88 /// Get a reference to the lowest layer.
89 lowest_layer_type& lowest_layer()
90 {
91 return next_layer_.lowest_layer();
92 }
93
94 /// Get a const reference to the lowest layer.
95 const lowest_layer_type& lowest_layer() const
96 {
97 return next_layer_.lowest_layer();
98 }
99
100 /// Get the io_service associated with the object.
101 boost::asio::io_service& get_io_service()
102 {
103 return next_layer_.get_io_service();
104 }
105
106 /// Close the stream.
107 void close()
108 {
109 next_layer_.close();
110 }
111
112 /// Close the stream.
113 boost::system::error_code close(boost::system::error_code& ec)
114 {
115 return next_layer_.close(ec);
116 }
117
118 /// Flush all data from the buffer to the next layer. Returns the number of
119 /// bytes written to the next layer on the last write operation. Throws an
120 /// exception on failure.
121 std::size_t flush();
122
123 /// Flush all data from the buffer to the next layer. Returns the number of
124 /// bytes written to the next layer on the last write operation, or 0 if an
125 /// error occurred.
126 std::size_t flush(boost::system::error_code& ec);
127
128 /// Start an asynchronous flush.
129 template <typename WriteHandler>
130 BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
131 void (boost::system::error_code, std::size_t))
132 async_flush(BOOST_ASIO_MOVE_ARG(WriteHandler) handler);
133
134 /// Write the given data to the stream. Returns the number of bytes written.
135 /// Throws an exception on failure.
136 template <typename ConstBufferSequence>
137 std::size_t write_some(const ConstBufferSequence& buffers);
138
139 /// Write the given data to the stream. Returns the number of bytes written,
140 /// or 0 if an error occurred and the error handler did not throw.
141 template <typename ConstBufferSequence>
142 std::size_t write_some(const ConstBufferSequence& buffers,
143 boost::system::error_code& ec);
144
145 /// Start an asynchronous write. The data being written must be valid for the
146 /// lifetime of the asynchronous operation.
147 template <typename ConstBufferSequence, typename WriteHandler>
148 BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
149 void (boost::system::error_code, std::size_t))
150 async_write_some(const ConstBufferSequence& buffers,
151 BOOST_ASIO_MOVE_ARG(WriteHandler) handler);
152
153 /// Read some data from the stream. Returns the number of bytes read. Throws
154 /// an exception on failure.
155 template <typename MutableBufferSequence>
156 std::size_t read_some(const MutableBufferSequence& buffers)
157 {
158 return next_layer_.read_some(buffers);
159 }
160
161 /// Read some data from the stream. Returns the number of bytes read or 0 if
162 /// an error occurred.
163 template <typename MutableBufferSequence>
164 std::size_t read_some(const MutableBufferSequence& buffers,
165 boost::system::error_code& ec)
166 {
167 return next_layer_.read_some(buffers, ec);
168 }
169
170 /// Start an asynchronous read. The buffer into which the data will be read
171 /// must be valid for the lifetime of the asynchronous operation.
172 template <typename MutableBufferSequence, typename ReadHandler>
173 BOOST_ASIO_INITFN_RESULT_TYPE(ReadHandler,
174 void (boost::system::error_code, std::size_t))
175 async_read_some(const MutableBufferSequence& buffers,
176 BOOST_ASIO_MOVE_ARG(ReadHandler) handler)
177 {
178 detail::async_result_init<
179 ReadHandler, void (boost::system::error_code, std::size_t)> init(
180 BOOST_ASIO_MOVE_CAST(ReadHandler)(handler));
181
182 next_layer_.async_read_some(buffers,
183 BOOST_ASIO_MOVE_CAST(BOOST_ASIO_HANDLER_TYPE(ReadHandler,
184 void (boost::system::error_code, std::size_t)))(init.handler));
185
186 return init.result.get();
187 }
188
189 /// Peek at the incoming data on the stream. Returns the number of bytes read.
190 /// Throws an exception on failure.
191 template <typename MutableBufferSequence>
192 std::size_t peek(const MutableBufferSequence& buffers)
193 {
194 return next_layer_.peek(buffers);
195 }
196
197 /// Peek at the incoming data on the stream. Returns the number of bytes read,
198 /// or 0 if an error occurred.
199 template <typename MutableBufferSequence>
200 std::size_t peek(const MutableBufferSequence& buffers,
201 boost::system::error_code& ec)
202 {
203 return next_layer_.peek(buffers, ec);
204 }
205
206 /// Determine the amount of data that may be read without blocking.
207 std::size_t in_avail()
208 {
209 return next_layer_.in_avail();
210 }
211
212 /// Determine the amount of data that may be read without blocking.
213 std::size_t in_avail(boost::system::error_code& ec)
214 {
215 return next_layer_.in_avail(ec);
216 }
217
218private:
219 /// Copy data into the internal buffer from the specified source buffer.
220 /// Returns the number of bytes copied.
221 template <typename ConstBufferSequence>
222 std::size_t copy(const ConstBufferSequence& buffers);
223
224 /// The next layer.
225 Stream next_layer_;
226
227 // The data in the buffer.
228 detail::buffered_stream_storage storage_;
229};
230
231} // namespace asio
232} // namespace boost
233
234#include <boost/asio/detail/pop_options.hpp>
235
236#include <boost/asio/impl/buffered_write_stream.hpp>
237
238#endif // BOOST_ASIO_BUFFERED_WRITE_STREAM_HPP
239