GCC Code Coverage Report

Line	Branch	Exec	Source
1			//
2			// Copyright (c) 2025 Vinnie Falco (vinnie dot falco at gmail dot com)
3			//
4			// Distributed under the Boost Software License, Version 1.0. (See accompanying
5			// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6			//
7			// Official repository: https://github.com/cppalliance/beast2
8			//
9
10			#ifndef BOOST_BEAST2_SERVER_WORKERS_HPP
11			#define BOOST_BEAST2_SERVER_WORKERS_HPP
12
13			#include <boost/beast2/detail/config.hpp>
14			#include <boost/beast2/application.hpp>
15			#include <boost/beast2/log_service.hpp>
16			#include <boost/beast2/server/fixed_array.hpp>
17			#include <boost/asio/basic_stream_socket.hpp>
18			#include <boost/asio/basic_socket_acceptor.hpp>
19			#include <boost/asio/dispatch.hpp>
20			#include <boost/asio/prepend.hpp>
21
22			namespace boost {
23			namespace beast2 {
24
25			class BOOST_SYMBOL_VISIBLE
26			workers_base
27			{
28			public:
29			BOOST_BEAST2_DECL
30			virtual ~workers_base();
31
32			virtual application& app() noexcept = 0;
33			virtual void do_idle(void* worker) = 0;
34			};
35
36			/** A set of accepting sockets and their workers.
37
38			This implements a set of listening ports as a server service. An array of
39			workers created upon construction is used to accept incoming connections
40			and handle their sessions.
41
42			@par Worker exemplar
43			@code
44			template< class Executor >
45			struct Worker
46			{
47			using executor_type = Executor;
48			using protocol_type = asio::ip::tcp;
49			using socket_type = asio::basic_stream_socket<protocol_type, Executor>;
50			using acceptor_config = beast2::acceptor_config;
51
52			asio::basic_stream_socket<protocol_type, Executor>& socket() noexcept;
53			typename protocol_type::endpoint& endpoint() noexcept;
54
55			void on_accept();
56			};
57			@endcode
58
59			@tparam Executor The type of executor used by acceptor sockets.
60			@tparam Worker The type of worker to use.
61			*/
62			template<class Worker>
63			class workers
64			: public workers_base
65			{
66			public:
67			using executor_type = typename Worker::executor_type;
68			using protocol_type = typename Worker::protocol_type;
69			using acceptor_type = asio::basic_socket_acceptor<protocol_type, executor_type>;
70			using acceptor_config = typename Worker::acceptor_config;
71			using socket_type = asio::basic_stream_socket<protocol_type, executor_type>;
72
73		✗	~workers()
74			{
75		✗	}
76
77			/** Constructor
78
79			@param app The @ref application which holds this part
80			@param ex The executor to use for acceptor sockets
81			@param concurrency The number of threads calling io_context::run
82			@param num_workers The number of workers to construct
83			@param args Arguments forwarded to each worker's constructor
84			*/
85			template<class Executor1, class... Args>
86			workers(
87			application& app,
88			Executor1 const& ex,
89			unsigned concurrency,
90			std::size_t num_workers,
91			Args&&... args);
92
93			/** Add an acceptor
94			*/
95			template<class... Args>
96			void
97		✗	emplace(
98			acceptor_config&& config,
99			Args&&... args)
100			{
101		✗	va_.emplace_back(
102		✗	concurrency_,
103		✗	std::move(config),
104		✗	acceptor_type(ex_,
105		✗	std::forward<Args>(args)...));
106		✗	}
107
108			void start();
109			void stop();
110
111			private:
112			struct acceptor;
113			struct worker;
114
115			application& app() noexcept override;
116			void do_idle(void*) override;
117			void do_accepts();
118			void on_accept(acceptor*, worker*,
119			system::error_code const&);
120			void do_stop();
121
122			application& app_;
123			section sect_;
124			executor_type ex_;
125			fixed_array<worker> vw_;
126			std::vector<acceptor> va_;
127			worker* idle_ = nullptr;
128			std::size_t n_idle_ = 0;
129			unsigned concurrency_;
130			bool stop_ = false;
131			};
132
133			//------------------------------------------------
134
135			template<class Worker>
136			struct workers<Worker>::
137			acceptor
138			{
139			template<class... Args>
140			explicit
141		✗	acceptor(
142			std::size_t concurrency,
143			acceptor_config&& config_,
144			acceptor_type&& sock_)
145		✗	: config(std::move(config_))
146		✗	, sock(std::move(sock_))
147		✗	, need(concurrency)
148			{
149		✗	}
150
151			acceptor_config config;
152			asio::basic_socket_acceptor<
153			protocol_type, executor_type> sock;
154			std::size_t need; // number of accepts we need
155			};
156
157			template<class Worker>
158			struct workers<Worker>::
159			worker
160			{
161			worker* next;
162			Worker w;
163
164			template<class... Args>
165		✗	explicit worker(
166			worker* next_, Args&&... args)
167		✗	: next(next_)
168		✗	, w(std::forward<Args>(args)...)
169			{
170		✗	}
171			};
172
173			//------------------------------------------------
174
175			template<class Worker>
176			template<class Executor1, class... Args>
177		✗	workers<Worker>::
178			workers(
179			application& app,
180			Executor1 const& ex,
181			unsigned concurrency,
182			std::size_t num_workers,
183			Args&&... args)
184		✗	: app_(app)
185		✗	, sect_(use_log_service(app).get_section("workers"))
186		✗	, ex_(executor_type(ex))
187		✗	, vw_(num_workers)
188		✗	, concurrency_(concurrency)
189			{
190		✗	while(! vw_.is_full())
191		✗	idle_ = &vw_.emplace_back(idle_, *this,
192			std::forward<Args>(args)...);
193		✗	n_idle_ = vw_.size();
194		✗	}
195
196			template<class Worker>
197			application&
198		✗	workers<Worker>::
199			app() noexcept
200			{
201		✗	return app_;
202			}
203
204			template<class Worker>
205			void
206		✗	workers<Worker>::
207			do_idle(void* pw)
208			{
209		✗	asio::dispatch(ex_,
210		✗	[this, pw]()
211			{
212			// recover the `worker` pointer without using offsetof
213		✗	worker* w = vw_.data() + (
214		✗	reinterpret_cast<std::uintptr_t>(pw) -
215		✗	reinterpret_cast<std::uintptr_t>(vw_.data())) /
216			sizeof(worker);
217			// push
218		✗	w->next = idle_;
219		✗	idle_ = w;
220		✗	++n_idle_;
221		✗	do_accepts();
222			});
223		✗	}
224			template<class Worker>
225			void
226		✗	workers<Worker>::
227			start()
228			{
229		✗	asio::dispatch(ex_, call_mf(&workers::do_accepts, this));
230		✗	}
231
232			template<class Worker>
233			void
234		✗	workers<Worker>::
235			stop()
236			{
237		✗	asio::dispatch(ex_, call_mf(&workers::do_stop, this));
238		✗	}
239
240			template<class Worker>
241			void
242		✗	workers<Worker>::
243			do_accepts()
244			{
245		✗	BOOST_ASSERT(ex_.running_in_this_thread());
246		✗	if(stop_)
247		✗	return;
248		✗	if(idle_)
249			{
250		✗	for(auto& a : va_)
251			{
252		✗	while(a.need > 0)
253			{
254		✗	--a.need;
255			// pop
256		✗	auto pw = idle_;
257		✗	idle_ = idle_->next;
258		✗	--n_idle_;
259		✗	a.sock.async_accept(pw->w.socket(), pw->w.endpoint(),
260		✗	asio::prepend(call_mf(&workers::on_accept, this), &a, pw));
261		✗	if(! idle_)
262		✗	goto busy;
263			}
264			}
265		✗	return;
266			}
267		✗	busy:
268			// all workers are busy
269			// VFALCO log to warn the server admin?
270		✗	return;
271			}
272
273			template<class Worker>
274			void
275		✗	workers<Worker>::
276			on_accept(
277			acceptor* pa,
278			worker* pw,
279			system::error_code const& ec)
280			{
281		✗	BOOST_ASSERT(ex_.running_in_this_thread());
282		✗	++pa->need;
283		✗	if(ec.failed())
284			{
285			// push
286		✗	pw->next = idle_;
287		✗	idle_ = pw;
288		✗	++n_idle_;
289		✗	LOG_DBG(sect_)("async_accept: {}", ec.message());
290		✗	return do_accepts();
291			}
292		✗	do_accepts();
293		✗	asio::dispatch(pw->w.socket().get_executor(), asio::prepend(
294		✗	call_mf(&Worker::on_accept, &pw->w), &pa->config));
295			}
296
297			template<class Worker>
298			void
299		✗	workers<Worker>::
300			do_stop()
301			{
302		✗	stop_ = true;
303
304		✗	for(auto& a : va_)
305			{
306		✗	system::error_code ec;
307		✗	a.sock.cancel(ec); // error ignored
308			}
309		✗	for(auto& w : vw_)
310		✗	w.w.cancel();
311		✗	}
312
313			} // beast2
314			} // boost
315
316			#endif
317