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b32b8144 FG |
1 | // |
2 | // executor_work_guard.hpp | |
20effc67 | 3 | // ~~~~~~~~~~~~~~~~~~~~~~~ |
b32b8144 | 4 | // |
f67539c2 | 5 | // Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
b32b8144 FG |
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_EXECUTOR_WORK_GUARD_HPP | |
12 | #define BOOST_ASIO_EXECUTOR_WORK_GUARD_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> | |
20effc67 TL |
19 | |
20 | #if !defined(BOOST_ASIO_NO_TS_EXECUTORS) | |
21 | ||
b32b8144 FG |
22 | #include <boost/asio/associated_executor.hpp> |
23 | #include <boost/asio/detail/type_traits.hpp> | |
20effc67 | 24 | #include <boost/asio/execution.hpp> |
b32b8144 FG |
25 | #include <boost/asio/is_executor.hpp> |
26 | ||
27 | #include <boost/asio/detail/push_options.hpp> | |
28 | ||
29 | namespace boost { | |
30 | namespace asio { | |
31 | ||
20effc67 TL |
32 | #if !defined(BOOST_ASIO_EXECUTOR_WORK_GUARD_DECL) |
33 | #define BOOST_ASIO_EXECUTOR_WORK_GUARD_DECL | |
34 | ||
35 | template <typename Executor, typename = void> | |
36 | class executor_work_guard; | |
37 | ||
38 | #endif // !defined(BOOST_ASIO_EXECUTOR_WORK_GUARD_DECL) | |
39 | ||
b32b8144 FG |
40 | /// An object of type @c executor_work_guard controls ownership of executor work |
41 | /// within a scope. | |
20effc67 | 42 | #if defined(GENERATING_DOCUMENTATION) |
b32b8144 | 43 | template <typename Executor> |
20effc67 TL |
44 | #else // defined(GENERATING_DOCUMENTATION) |
45 | template <typename Executor, typename> | |
46 | #endif // defined(GENERATING_DOCUMENTATION) | |
b32b8144 FG |
47 | class executor_work_guard |
48 | { | |
49 | public: | |
50 | /// The underlying executor type. | |
51 | typedef Executor executor_type; | |
52 | ||
53 | /// Constructs a @c executor_work_guard object for the specified executor. | |
54 | /** | |
55 | * Stores a copy of @c e and calls <tt>on_work_started()</tt> on it. | |
56 | */ | |
57 | explicit executor_work_guard(const executor_type& e) BOOST_ASIO_NOEXCEPT | |
58 | : executor_(e), | |
59 | owns_(true) | |
60 | { | |
61 | executor_.on_work_started(); | |
62 | } | |
63 | ||
64 | /// Copy constructor. | |
65 | executor_work_guard(const executor_work_guard& other) BOOST_ASIO_NOEXCEPT | |
66 | : executor_(other.executor_), | |
67 | owns_(other.owns_) | |
68 | { | |
69 | if (owns_) | |
70 | executor_.on_work_started(); | |
71 | } | |
72 | ||
73 | #if defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION) | |
74 | /// Move constructor. | |
92f5a8d4 | 75 | executor_work_guard(executor_work_guard&& other) BOOST_ASIO_NOEXCEPT |
b32b8144 FG |
76 | : executor_(BOOST_ASIO_MOVE_CAST(Executor)(other.executor_)), |
77 | owns_(other.owns_) | |
78 | { | |
79 | other.owns_ = false; | |
80 | } | |
81 | #endif // defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION) | |
82 | ||
83 | /// Destructor. | |
84 | /** | |
85 | * Unless the object has already been reset, or is in a moved-from state, | |
86 | * calls <tt>on_work_finished()</tt> on the stored executor. | |
87 | */ | |
88 | ~executor_work_guard() | |
89 | { | |
90 | if (owns_) | |
91 | executor_.on_work_finished(); | |
92 | } | |
93 | ||
94 | /// Obtain the associated executor. | |
95 | executor_type get_executor() const BOOST_ASIO_NOEXCEPT | |
96 | { | |
97 | return executor_; | |
98 | } | |
99 | ||
100 | /// Whether the executor_work_guard object owns some outstanding work. | |
101 | bool owns_work() const BOOST_ASIO_NOEXCEPT | |
102 | { | |
103 | return owns_; | |
104 | } | |
105 | ||
106 | /// Indicate that the work is no longer outstanding. | |
f67539c2 | 107 | /** |
b32b8144 FG |
108 | * Unless the object has already been reset, or is in a moved-from state, |
109 | * calls <tt>on_work_finished()</tt> on the stored executor. | |
110 | */ | |
111 | void reset() BOOST_ASIO_NOEXCEPT | |
112 | { | |
113 | if (owns_) | |
114 | { | |
115 | executor_.on_work_finished(); | |
116 | owns_ = false; | |
117 | } | |
118 | } | |
119 | ||
120 | private: | |
121 | // Disallow assignment. | |
122 | executor_work_guard& operator=(const executor_work_guard&); | |
123 | ||
124 | executor_type executor_; | |
125 | bool owns_; | |
126 | }; | |
127 | ||
20effc67 TL |
128 | #if !defined(GENERATING_DOCUMENTATION) |
129 | ||
130 | template <typename Executor> | |
131 | class executor_work_guard<Executor, | |
132 | typename enable_if< | |
133 | !is_executor<Executor>::value && execution::is_executor<Executor>::value | |
134 | >::type> | |
135 | { | |
136 | public: | |
137 | typedef Executor executor_type; | |
138 | ||
139 | explicit executor_work_guard(const executor_type& e) BOOST_ASIO_NOEXCEPT | |
140 | : executor_(e), | |
141 | owns_(true) | |
142 | { | |
143 | new (&work_) work_type(boost::asio::prefer(executor_, | |
144 | execution::outstanding_work.tracked)); | |
145 | } | |
146 | ||
147 | executor_work_guard(const executor_work_guard& other) BOOST_ASIO_NOEXCEPT | |
148 | : executor_(other.executor_), | |
149 | owns_(other.owns_) | |
150 | { | |
151 | if (owns_) | |
152 | { | |
153 | new (&work_) work_type(boost::asio::prefer(executor_, | |
154 | execution::outstanding_work.tracked)); | |
155 | } | |
156 | } | |
157 | ||
158 | #if defined(BOOST_ASIO_HAS_MOVE) | |
159 | executor_work_guard(executor_work_guard&& other) BOOST_ASIO_NOEXCEPT | |
160 | : executor_(BOOST_ASIO_MOVE_CAST(Executor)(other.executor_)), | |
161 | owns_(other.owns_) | |
162 | { | |
163 | if (owns_) | |
164 | { | |
165 | new (&work_) work_type( | |
166 | BOOST_ASIO_MOVE_CAST(work_type)( | |
167 | *static_cast<work_type*>( | |
168 | static_cast<void*>(&other.work_)))); | |
169 | other.owns_ = false; | |
170 | } | |
171 | } | |
172 | #endif // defined(BOOST_ASIO_HAS_MOVE) | |
173 | ||
174 | ~executor_work_guard() | |
175 | { | |
176 | if (owns_) | |
177 | static_cast<work_type*>(static_cast<void*>(&work_))->~work_type(); | |
178 | } | |
179 | ||
180 | executor_type get_executor() const BOOST_ASIO_NOEXCEPT | |
181 | { | |
182 | return executor_; | |
183 | } | |
184 | ||
185 | bool owns_work() const BOOST_ASIO_NOEXCEPT | |
186 | { | |
187 | return owns_; | |
188 | } | |
189 | ||
190 | void reset() BOOST_ASIO_NOEXCEPT | |
191 | { | |
192 | if (owns_) | |
193 | { | |
194 | static_cast<work_type*>(static_cast<void*>(&work_))->~work_type(); | |
195 | owns_ = false; | |
196 | } | |
197 | } | |
198 | ||
199 | private: | |
200 | // Disallow assignment. | |
201 | executor_work_guard& operator=(const executor_work_guard&); | |
202 | ||
203 | typedef typename decay< | |
204 | typename prefer_result< | |
205 | const executor_type&, | |
206 | execution::outstanding_work_t::tracked_t | |
207 | >::type | |
208 | >::type work_type; | |
209 | ||
210 | executor_type executor_; | |
211 | typename aligned_storage<sizeof(work_type), | |
212 | alignment_of<work_type>::value>::type work_; | |
213 | bool owns_; | |
214 | }; | |
215 | ||
216 | #endif // !defined(GENERATING_DOCUMENTATION) | |
217 | ||
b32b8144 FG |
218 | /// Create an @ref executor_work_guard object. |
219 | template <typename Executor> | |
220 | inline executor_work_guard<Executor> make_work_guard(const Executor& ex, | |
20effc67 TL |
221 | typename enable_if< |
222 | is_executor<Executor>::value || execution::is_executor<Executor>::value | |
223 | >::type* = 0) | |
b32b8144 FG |
224 | { |
225 | return executor_work_guard<Executor>(ex); | |
226 | } | |
227 | ||
228 | /// Create an @ref executor_work_guard object. | |
229 | template <typename ExecutionContext> | |
230 | inline executor_work_guard<typename ExecutionContext::executor_type> | |
231 | make_work_guard(ExecutionContext& ctx, | |
232 | typename enable_if< | |
20effc67 TL |
233 | is_convertible<ExecutionContext&, execution_context&>::value |
234 | >::type* = 0) | |
b32b8144 FG |
235 | { |
236 | return executor_work_guard<typename ExecutionContext::executor_type>( | |
237 | ctx.get_executor()); | |
238 | } | |
239 | ||
240 | /// Create an @ref executor_work_guard object. | |
241 | template <typename T> | |
242 | inline executor_work_guard<typename associated_executor<T>::type> | |
243 | make_work_guard(const T& t, | |
20effc67 TL |
244 | typename enable_if< |
245 | !is_executor<T>::value && !execution::is_executor<T>::value | |
246 | && !is_convertible<T&, execution_context& | |
247 | >::value>::type* = 0) | |
b32b8144 FG |
248 | { |
249 | return executor_work_guard<typename associated_executor<T>::type>( | |
250 | associated_executor<T>::get(t)); | |
251 | } | |
252 | ||
253 | /// Create an @ref executor_work_guard object. | |
254 | template <typename T, typename Executor> | |
255 | inline executor_work_guard<typename associated_executor<T, Executor>::type> | |
256 | make_work_guard(const T& t, const Executor& ex, | |
20effc67 TL |
257 | typename enable_if< |
258 | is_executor<Executor>::value || execution::is_executor<Executor>::value | |
259 | >::type* = 0) | |
b32b8144 FG |
260 | { |
261 | return executor_work_guard<typename associated_executor<T, Executor>::type>( | |
262 | associated_executor<T, Executor>::get(t, ex)); | |
263 | } | |
264 | ||
265 | /// Create an @ref executor_work_guard object. | |
266 | template <typename T, typename ExecutionContext> | |
267 | inline executor_work_guard<typename associated_executor<T, | |
268 | typename ExecutionContext::executor_type>::type> | |
269 | make_work_guard(const T& t, ExecutionContext& ctx, | |
20effc67 TL |
270 | typename enable_if< |
271 | !is_executor<T>::value && !execution::is_executor<T>::value | |
272 | && !is_convertible<T&, execution_context&>::value | |
273 | && is_convertible<ExecutionContext&, execution_context&>::value | |
274 | >::type* = 0) | |
b32b8144 FG |
275 | { |
276 | return executor_work_guard<typename associated_executor<T, | |
277 | typename ExecutionContext::executor_type>::type>( | |
278 | associated_executor<T, typename ExecutionContext::executor_type>::get( | |
279 | t, ctx.get_executor())); | |
280 | } | |
281 | ||
282 | } // namespace asio | |
283 | } // namespace boost | |
284 | ||
285 | #include <boost/asio/detail/pop_options.hpp> | |
286 | ||
20effc67 TL |
287 | #endif // !defined(BOOST_ASIO_NO_TS_EXECUTORS) |
288 | ||
b32b8144 | 289 | #endif // BOOST_ASIO_EXECUTOR_WORK_GUARD_HPP |