1 // This is free and unencumbered software released into the public domain.
2 //
3 // Anyone is free to copy, modify, publish, use, compile, sell, or
4 // distribute this software, either in source code form or as a compiled
5 // binary, for any purpose, commercial or non-commercial, and by any
6 // means.
7 //
8 // In jurisdictions that recognize copyright laws, the author or authors
9 // of this software dedicate any and all copyright interest in the
10 // software to the public domain. We make this dedication for the benefit
11 // of the public at large and to the detriment of our heirs and
12 // successors. We intend this dedication to be an overt act of
13 // relinquishment in perpetuity of all present and future rights to this
14 // software under copyright law.
15 //
16 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
19 // IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
20 // OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21 // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22 // OTHER DEALINGS IN THE SOFTWARE.
23 
24 // XXX would be nice to eventually have multiple backends for poll,
25 // kqueue, epoll.
26 
27 use errors;
28 use io;
29 use unix;
30 use unix::poll;
31 use unix::signal;
32 
33 export type event = enum i16 {
34 	READ,
35 	WRITE,
36 };
37 
38 export def READ = event::READ;
39 export def WRITE = event::WRITE;
40 
41 type cb = struct {
42 	cb: *fn(io::file, event, nullable *opaque) void,
43 	data: nullable *opaque,
44 };
45 
46 type queue = struct {
47 	pfds: []poll::pollfd,
48 	cbs: []cb,
49 };
50 
51 // XXX we should hide the poll::error and return 'just' an error.
52 // maybe.
53 export type evloop = struct {
54 	add: *fn(*evloop, io::file, event, *fn(io::file, event, nullable *opaque) void, nullable *opaque) void,
55 	del: *fn(*evloop, io::file) void,
56 	loop: *fn(*evloop) (void | poll::error),
57 	loopbreak: *fn(*evloop) void,
58 };
59 
60 type base = struct {
61 	evloop,
62 	working: queue,
63 	wip: queue,
64 	sigpipe: (void | (io::file, io::file)),
65 	sigcb: (void | *fn(signal::sig, nullable *opaque) void),
66 	sigdata: nullable *opaque,
67 	stop: bool, // signal to stop
68 	// TODO: timeout
69 };
70 
71 export fn new() *evloop = alloc(base {
72 	add = &evadd,
73 	del = &evdel,
74 	loop = &loop,
75 	loopbreak = &evloopbreak,
76 	sigpipe = void,
77 	sigcb = void,
78 	...
79 });
80 
81 fn ev2poll(ev: event) poll::event = switch (ev) {
82 	case event::READ => yield poll::event::POLLIN;
83 	case event::WRITE => yield poll::event::POLLOUT;
84 };
85 
86 fn poll2ev(ev: i16) event = {
87 	if ((ev & poll::event::POLLOUT) != 0) {
88 		return event::WRITE;
89 	};
90 	return event::READ;
91 };
92 
93 export fn evadd(
94 	evloop: *evloop,
95 	fd: io::file,
96 	ev: event,
97 	f: *fn(io::file, event, nullable *opaque) void,
98 	data: nullable *opaque
99 ) void = {
100 	const b = evloop: *base;
101 
102 	for (let i = 0z; i < len(b.wip.pfds); i += 1) {
103 		if (b.wip.pfds[i].fd != fd)
104 			continue;
105 		b.wip.pfds[i].events = ev2poll(ev);
106 		b.wip.cbs[i] = cb { cb = f, data = data };
107 		return;
108 	};
109 
110 	append(b.wip.pfds, poll::pollfd {
111 		fd = fd,
112 		events = ev2poll(ev),
113 		...
114 	});
115 	append(b.wip.cbs, cb {
116 		cb = f,
117 		data = data,
118 	});
119 };
120 
121 export fn evdel(evloop: *evloop, fd: io::file) void = {
122 	const b = evloop: *base;
123 	for (let i = 0z; i < len(b.wip.pfds); i += 1) {
124 		if (b.wip.pfds[i].fd != fd) {
125 			continue;
126 		};
127 		delete(b.wip.pfds[i]);
128 		delete(b.wip.cbs[i]);
129 		return;
130 	};
131 };
132 
133 fn prepare_queue(b: *base) void = {
134 	delete(b.working.pfds[..]);
135 	delete(b.working.cbs[..]);
136 
137 	for (let i = 0z; i < len(b.wip.pfds); i += 1) {
138 		append(b.working.pfds, b.wip.pfds[i]);
139 		append(b.working.cbs, b.wip.cbs[i]);
140 	};
141 };
142 
143 export fn loop(evloop: *evloop) (void | poll::error) = {
144 	const b = evloop: *base;
145 
146 	const mask = poll::event::POLLIN | poll::event::POLLOUT |
147 		poll::event::POLLHUP;
148 
149 	for (!b.stop) {
150 		prepare_queue(b);
151 
152 		let q = b.working;
153 
154 		let n = match (poll::poll(q.pfds, poll::INDEF)) {
155 		case let err: errors::interrupted =>
156 			continue;
157 		case let err: errors::error =>
158 			return err;
159 		case let n: uint => yield n;
160 		};
161 
162 		for (let i = 0z; i < len(q.pfds); i += 1) {
163 			// XXX check for POLLNVAL ?
164 
165 			if ((q.pfds[i].revents & mask) == 0) {
166 				continue;
167 			};
168 			q.cbs[i].cb(q.pfds[i].fd, poll2ev(q.pfds[i].revents),
169 				q.cbs[i].data);
170 		};
171 	};
172 };
173 
174 export fn evloopbreak(evloop: *evloop) void = {
175 	const b = evloop: *base;
176 	b.stop = true;
177 };