HTML Diff spawn/parallel

src/examples/cpp03/spawn/parallel_grep.cpp		src/examples/cpp11/spawn/parallel_grep.cpp
⋮		⋮
1	//	1	//
2	//·parallel_grep.cpp	2	//·parallel_grep.cpp
3	//·~~~~~~~~~~~~~~~~~	3	//·~~~~~~~~~~~~~~~~~
4	//	4	//
5	//·Copyright·(c)·2003-2023·Christopher·M.·Kohlhoff·(chris·at·kohlhoff·dot·com)	5	//·Copyright·(c)·2003-2023·Christopher·M.·Kohlhoff·(chris·at·kohlhoff·dot·com)
6	//	6	//
7	//·Distributed·under·the·Boost·Software·License,·Version·1.0.·(See·accompanying	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)	8	//·file·LICENSE_1_0.txt·or·copy·at·http://www.boost.org/LICENSE_1_0.txt)
9	//	9	//
10		10
11	#include·<asio/detached.hpp>	11	#include·<asio/detached.hpp>
12	#include·<asio/dispatch.hpp>	12	#include·<asio/dispatch.hpp>
13	#include·<asio/post.hpp>	13	#include·<asio/post.hpp>
14	#include·<asio/spawn.hpp>	14	#include·<asio/spawn.hpp>
15	#include·<asio/strand.hpp>	15	#include·<asio/strand.hpp>
16	#include·<asio/thread_pool.hpp>	16	#include·<asio/thread_pool.hpp>
17	#include·<boost/bind/bind.hpp>
18	#include·<fstream>	17	#include·<fstream>
19	#include·<iostream>	18	#include·<iostream>
20	#include·<string>	19	#include·<string>
21		20
22	using·asio::detached_t;	21	using·asio::detached;
23	using·asio::dispatch;	22	using·asio::dispatch;
24	using·asio::spawn;	23	using·asio::spawn;
25	using·asio::strand;	24	using·asio::strand;
26	using·asio::thread_pool;	25	using·asio::thread_pool;
27	using·asio::yield_context;	26	using·asio::yield_context;
28		27
29	void·print_match(std::string·input_file,·std::string·line)
30	{
31	··std::cout·<<·input_file·<<·':'·<<·line·<<·std::endl;
32	}
33
34	void·search_file(std::string·search_string,·std::string·input_file,
35	····strand<thread_pool::executor_type>·output_strand,·yield_context·yield)
36	{
37	··std::ifstream·is(input_file.c_str());
38	··std::string·line;
39	··std::size_t·line_num·=·0;
40	··while·(std::getline(is,·line))
41	··{
42	····//·If·we·find·a·match,·send·a·message·to·the·output.
43	····if·(line.find(search_string)·!=·std::string::npos)
44	····{
45	······dispatch(output_strand,·boost::bind(&print_match,·input_file,·line));
46	····}
47
48	····//·Every·so·often·we·yield·control·to·another·coroutine.
49	····if·(++line_num·%·10·==·0)
50	······post(yield);
51	··}
52	}
53
54	int·main(int·argc,·char*·argv[])	28	int·main(int·argc,·char*·argv[])
55	{	29	{
56	··try	30	··try
57	··{	31	··{
58	····if·(argc·<·2)	32	····if·(argc·<·2)
59	····{	33	····{
60	······std::cerr·<<·"Usage:·parallel_grep·<string>·<files...>\n";	34	······std::cerr·<<·"Usage:·parallel_grep·<string>·<files...>\n";
61	······return·1;	35	······return·1;
62	····}	36	····}
63		37
64	····//·We·use·a·fixed·size·pool·of·threads·for·reading·the·input·files.·The	38	····//·We·use·a·fixed·size·pool·of·threads·for·reading·the·input·files.·The
65	····//·number·of·threads·is·automatically·determined·based·on·the·number·of	39	····//·number·of·threads·is·automatically·determined·based·on·the·number·of
66	····//·CPUs·available·in·the·system.	40	····//·CPUs·available·in·the·system.
67	····thread_pool·pool;	41	····thread_pool·pool;
68		42
69	····//·To·prevent·the·output·from·being·garbled,·we·use·a·strand·to·synchronise	43	····//·To·prevent·the·output·from·being·garbled,·we·use·a·strand·to·synchronise
70	····//·printing.	44	····//·printing.
71	····strand<thread_pool::executor_type>·output_strand(pool.get_executor());	45	····strand<thread_pool::executor_type>·output_strand(pool.get_executor());
72		46
73	····//·Spawn·a·new·coroutine·for·each·file·specified·on·the·command·line.	47	····//·Spawn·a·new·coroutine·for·each·file·specified·on·the·command·line.
74	····std::string·search_string·=·argv[1];	48	····std::string·search_string·=·argv[1];
75	····for·(int·argn·=·2;·argn·<·argc;·++argn)	49	····for·(int·argn·=·2;·argn·<·argc;·++argn)
76	····{	50	····{
77	······std::string·input_file·=·argv[argn];	51	······std::string·input_file·=·argv[argn];
78	······spawn(pool,	52	······spawn(pool,
79	··········boost::bind(&search_file,·search_string,	53	········[=](yield_context·yield)
80	············input_file,·output_strand,·boost::placeholders::_1),	54	········{
81	··········detached_t());	55	··········std::ifstream·is(input_file.c_str());
		56	··········std::string·line;
		57	··········std::size_t·line_num·=·0;
		58	··········while·(std::getline(is,·line))
		59	··········{
		60	············//·If·we·find·a·match,·send·a·message·to·the·output.
		61	············if·(line.find(search_string)·!=·std::string::npos)
		62	············{
		63	··············dispatch(output_strand,
		64	··················[=]
		65	··················{
		66	····················std::cout·<<·input_file·<<·':'·<<·line·<<·std::endl;
		67	··················});
		68	············}
		69
		70	············//·Every·so·often·we·yield·control·to·another·coroutine.
		71	············if·(++line_num·%·10·==·0)
		72	··············post(yield);
		73	··········}
		74	········},·detached);
82	····}	75	····}
83		76
84	····//·Join·the·thread·pool·to·wait·for·all·the·spawned·tasks·to·complete.	77	····//·Join·the·thread·pool·to·wait·for·all·the·spawned·tasks·to·complete.
85	····pool.join();	78	····pool.join();
86	··}	79	··}
87	··catch·(std::exception&·e)	80	··catch·(std::exception&·e)
88	··{	81	··{
89	····std::cerr·<<·"Exception:·"·<<·e.what()·<<·"\n";	82	····std::cerr·<<·"Exception:·"·<<·e.what()·<<·"\n";
90	··}	83	··}
91		84
92	··return·0;	85	··return·0;
93	}	86	}