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 type base = struct {
52 	working: queue,
53 	wip: queue,
54 	sigpipe: ((io::file, io::file) | void),
55 	sigcb: (cb | void),
56 	stop: bool, // signal to stop
57 	// TODO: timeout
58 };
59 
60 let b = base {
61 	sigpipe = void,
62 	sigcb = void,
63 	...
64 };
65 
66 fn ev2poll(ev: event) poll::event = switch (ev) {
67 	case event::READ => yield poll::event::POLLIN;
68 	case event::WRITE => yield poll::event::POLLOUT;
69 };
70 
71 fn poll2ev(ev: i16) event = {
72 	if ((ev & poll::event::POLLOUT) != 0) {
73 		return event::WRITE;
74 	};
75 	return event::READ;
76 };
77 
78 export fn add(fd: io::file, ev: event, f: *fn(io::file, event, nullable *opaque) void, data: nullable *opaque) void = {
79 	append(b.wip.pfds, poll::pollfd {
80 		fd = fd,
81 		events = ev2poll(ev),
82 		...
83 	});
84 	append(b.wip.cbs, cb {
85 		cb = f,
86 		data = data,
87 	});
88 };
89 
90 export fn del(fd: io::file) void = {
91 	for (let i = 0z; i < len(b.wip.pfds); i += 1) {
92 		if (b.wip.pfds[i].fd != fd) {
93 			continue;
94 		};
95 		delete(b.wip.pfds[i]);
96 		delete(b.wip.cbs[i]);
97 		return;
98 	};
99 };
100 
101 fn prepare_queue() void = {
102 	let wip = b.wip;
103 
104 	if (len(b.working.pfds) > 0) {
105 		delete(b.working.pfds[..]);
106 		delete(b.working.cbs[..]);
107 	};
108 
109 	for (let i = 0z; i < len(wip.pfds); i += 1) {
110 		append(b.working.pfds, wip.pfds[i]);
111 		append(b.working.cbs, wip.cbs[i]);
112 	};
113 };
114 
115 export fn loop() (void | poll::error) = {
116 	const mask = poll::event::POLLIN | poll::event::POLLOUT |
117 		poll::event::POLLHUP;
118 
119 	for (!b.stop) {
120 		prepare_queue();
121 
122 		let q = b.working;
123 
124 		let n = poll::poll(q.pfds, poll::INDEF)?;
125 		for (let i = 0z; i < len(q.pfds); i += 1) {
126 			if ((q.pfds[i].revents & mask) == 0) {
127 				continue;
128 			};
129 			q.cbs[i].cb(q.pfds[i].fd, poll2ev(q.pfds[i].revents),
130 				q.cbs[i].data);
131 		};
132 	};
133 };
134 
135 export fn loopexit() void = {
136 	b.stop = true;
137 };