1 | // |
2 | // buffered_write_stream.hpp |
3 | // ~~~~~~~~~~~~~~~~~~~~~~~~~ |
4 | // |
5 | // Copyright (c) 2003-2024 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/write.hpp> |
29 | |
30 | #include <boost/asio/detail/push_options.hpp> |
31 | |
32 | namespace boost { |
33 | namespace asio { |
34 | namespace detail { |
35 | |
36 | template <typename> class initiate_async_buffered_flush; |
37 | template <typename> class initiate_async_buffered_write_some; |
38 | |
39 | } // namespace detail |
40 | |
41 | /// Adds buffering to the write-related operations of a stream. |
42 | /** |
43 | * The buffered_write_stream class template can be used to add buffering to the |
44 | * synchronous and asynchronous write operations of a stream. |
45 | * |
46 | * @par Thread Safety |
47 | * @e Distinct @e objects: Safe.@n |
48 | * @e Shared @e objects: Unsafe. |
49 | * |
50 | * @par Concepts: |
51 | * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream. |
52 | */ |
53 | template <typename Stream> |
54 | class buffered_write_stream |
55 | : private noncopyable |
56 | { |
57 | public: |
58 | /// The type of the next layer. |
59 | typedef remove_reference_t<Stream> next_layer_type; |
60 | |
61 | /// The type of the lowest layer. |
62 | typedef typename next_layer_type::lowest_layer_type lowest_layer_type; |
63 | |
64 | /// The type of the executor associated with the object. |
65 | typedef typename lowest_layer_type::executor_type executor_type; |
66 | |
67 | #if defined(GENERATING_DOCUMENTATION) |
68 | /// The default buffer size. |
69 | static const std::size_t default_buffer_size = implementation_defined; |
70 | #else |
71 | BOOST_ASIO_STATIC_CONSTANT(std::size_t, default_buffer_size = 1024); |
72 | #endif |
73 | |
74 | /// Construct, passing the specified argument to initialise the next layer. |
75 | template <typename Arg> |
76 | explicit buffered_write_stream(Arg&& a) |
77 | : next_layer_(static_cast<Arg&&>(a)), |
78 | storage_(default_buffer_size) |
79 | { |
80 | } |
81 | |
82 | /// Construct, passing the specified argument to initialise the next layer. |
83 | template <typename Arg> |
84 | buffered_write_stream(Arg&& a, |
85 | std::size_t buffer_size) |
86 | : next_layer_(static_cast<Arg&&>(a)), |
87 | storage_(buffer_size) |
88 | { |
89 | } |
90 | |
91 | /// Get a reference to the next layer. |
92 | next_layer_type& next_layer() |
93 | { |
94 | return next_layer_; |
95 | } |
96 | |
97 | /// Get a reference to the lowest layer. |
98 | lowest_layer_type& lowest_layer() |
99 | { |
100 | return next_layer_.lowest_layer(); |
101 | } |
102 | |
103 | /// Get a const reference to the lowest layer. |
104 | const lowest_layer_type& lowest_layer() const |
105 | { |
106 | return next_layer_.lowest_layer(); |
107 | } |
108 | |
109 | /// Get the executor associated with the object. |
110 | executor_type get_executor() noexcept |
111 | { |
112 | return next_layer_.lowest_layer().get_executor(); |
113 | } |
114 | |
115 | /// Close the stream. |
116 | void close() |
117 | { |
118 | next_layer_.close(); |
119 | } |
120 | |
121 | /// Close the stream. |
122 | BOOST_ASIO_SYNC_OP_VOID close(boost::system::error_code& ec) |
123 | { |
124 | next_layer_.close(ec); |
125 | BOOST_ASIO_SYNC_OP_VOID_RETURN(ec); |
126 | } |
127 | |
128 | /// Flush all data from the buffer to the next layer. Returns the number of |
129 | /// bytes written to the next layer on the last write operation. Throws an |
130 | /// exception on failure. |
131 | std::size_t flush(); |
132 | |
133 | /// Flush all data from the buffer to the next layer. Returns the number of |
134 | /// bytes written to the next layer on the last write operation, or 0 if an |
135 | /// error occurred. |
136 | std::size_t flush(boost::system::error_code& ec); |
137 | |
138 | /// Start an asynchronous flush. |
139 | /** |
140 | * @par Completion Signature |
141 | * @code void(boost::system::error_code, std::size_t) @endcode |
142 | */ |
143 | template < |
144 | BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, |
145 | std::size_t)) WriteHandler = default_completion_token_t<executor_type>> |
146 | auto async_flush( |
147 | WriteHandler&& handler = default_completion_token_t<executor_type>()) |
148 | -> decltype( |
149 | async_initiate<WriteHandler, |
150 | void (boost::system::error_code, std::size_t)>( |
151 | declval<detail::initiate_async_buffered_flush<Stream>>(), |
152 | handler, declval<detail::buffered_stream_storage*>())); |
153 | |
154 | /// Write the given data to the stream. Returns the number of bytes written. |
155 | /// Throws an exception on failure. |
156 | template <typename ConstBufferSequence> |
157 | std::size_t write_some(const ConstBufferSequence& buffers); |
158 | |
159 | /// Write the given data to the stream. Returns the number of bytes written, |
160 | /// or 0 if an error occurred and the error handler did not throw. |
161 | template <typename ConstBufferSequence> |
162 | std::size_t write_some(const ConstBufferSequence& buffers, |
163 | boost::system::error_code& ec); |
164 | |
165 | /// Start an asynchronous write. The data being written must be valid for the |
166 | /// lifetime of the asynchronous operation. |
167 | /** |
168 | * @par Completion Signature |
169 | * @code void(boost::system::error_code, std::size_t) @endcode |
170 | */ |
171 | template <typename ConstBufferSequence, |
172 | BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, |
173 | std::size_t)) WriteHandler = default_completion_token_t<executor_type>> |
174 | auto async_write_some(const ConstBufferSequence& buffers, |
175 | WriteHandler&& handler = default_completion_token_t<executor_type>()) |
176 | -> decltype( |
177 | async_initiate<WriteHandler, |
178 | void (boost::system::error_code, std::size_t)>( |
179 | declval<detail::initiate_async_buffered_write_some<Stream>>(), |
180 | handler, declval<detail::buffered_stream_storage*>(), buffers)); |
181 | |
182 | /// Read some data from the stream. Returns the number of bytes read. Throws |
183 | /// an exception on failure. |
184 | template <typename MutableBufferSequence> |
185 | std::size_t read_some(const MutableBufferSequence& buffers) |
186 | { |
187 | return next_layer_.read_some(buffers); |
188 | } |
189 | |
190 | /// Read some data from the stream. Returns the number of bytes read or 0 if |
191 | /// an error occurred. |
192 | template <typename MutableBufferSequence> |
193 | std::size_t read_some(const MutableBufferSequence& buffers, |
194 | boost::system::error_code& ec) |
195 | { |
196 | return next_layer_.read_some(buffers, ec); |
197 | } |
198 | |
199 | /// Start an asynchronous read. The buffer into which the data will be read |
200 | /// must be valid for the lifetime of the asynchronous operation. |
201 | /** |
202 | * @par Completion Signature |
203 | * @code void(boost::system::error_code, std::size_t) @endcode |
204 | */ |
205 | template <typename MutableBufferSequence, |
206 | BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, |
207 | std::size_t)) ReadHandler = default_completion_token_t<executor_type>> |
208 | auto async_read_some(const MutableBufferSequence& buffers, |
209 | ReadHandler&& handler = default_completion_token_t<executor_type>()) |
210 | -> decltype( |
211 | declval<conditional_t<true, Stream&, ReadHandler>>().async_read_some( |
212 | buffers, static_cast<ReadHandler&&>(handler))) |
213 | { |
214 | return next_layer_.async_read_some(buffers, |
215 | static_cast<ReadHandler&&>(handler)); |
216 | } |
217 | |
218 | /// Peek at the incoming data on the stream. Returns the number of bytes read. |
219 | /// Throws an exception on failure. |
220 | template <typename MutableBufferSequence> |
221 | std::size_t peek(const MutableBufferSequence& buffers) |
222 | { |
223 | return next_layer_.peek(buffers); |
224 | } |
225 | |
226 | /// Peek at the incoming data on the stream. Returns the number of bytes read, |
227 | /// or 0 if an error occurred. |
228 | template <typename MutableBufferSequence> |
229 | std::size_t peek(const MutableBufferSequence& buffers, |
230 | boost::system::error_code& ec) |
231 | { |
232 | return next_layer_.peek(buffers, ec); |
233 | } |
234 | |
235 | /// Determine the amount of data that may be read without blocking. |
236 | std::size_t in_avail() |
237 | { |
238 | return next_layer_.in_avail(); |
239 | } |
240 | |
241 | /// Determine the amount of data that may be read without blocking. |
242 | std::size_t in_avail(boost::system::error_code& ec) |
243 | { |
244 | return next_layer_.in_avail(ec); |
245 | } |
246 | |
247 | private: |
248 | /// Copy data into the internal buffer from the specified source buffer. |
249 | /// Returns the number of bytes copied. |
250 | template <typename ConstBufferSequence> |
251 | std::size_t copy(const ConstBufferSequence& buffers); |
252 | |
253 | /// The next layer. |
254 | Stream next_layer_; |
255 | |
256 | // The data in the buffer. |
257 | detail::buffered_stream_storage storage_; |
258 | }; |
259 | |
260 | } // namespace asio |
261 | } // namespace boost |
262 | |
263 | #include <boost/asio/detail/pop_options.hpp> |
264 | |
265 | #include <boost/asio/impl/buffered_write_stream.hpp> |
266 | |
267 | #endif // BOOST_ASIO_BUFFERED_WRITE_STREAM_HPP |
268 | |