1 |
/* |
2 |
iom.C -- generic I/O multiplexor |
3 |
Copyright (C) 2003 Marc Lehmann <pcg@goof.com> |
4 |
|
5 |
This program is free software; you can redistribute it and/or modify |
6 |
it under the terms of the GNU General Public License as published by |
7 |
the Free Software Foundation; either version 2 of the License, or |
8 |
(at your option) any later version. |
9 |
|
10 |
This program is distributed in the hope that it will be useful, |
11 |
but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
13 |
GNU General Public License for more details. |
14 |
|
15 |
You should have received a copy of the GNU General Public License |
16 |
along with this program; if not, write to the Free Software |
17 |
Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
18 |
*/ |
19 |
|
20 |
#include "../config.h" |
21 |
|
22 |
#include <cstdio> |
23 |
#include <cstdlib> |
24 |
#include <cerrno> |
25 |
|
26 |
#include <sys/select.h> |
27 |
#include <sys/time.h> |
28 |
|
29 |
#include "iom.h" |
30 |
|
31 |
// TSTAMP_MAX must still fit into a positive struct timeval |
32 |
#define TSTAMP_MAX (double)(1UL<<31) |
33 |
|
34 |
tstamp NOW; |
35 |
static bool iom_valid; |
36 |
io_manager iom; |
37 |
|
38 |
template<class watcher> |
39 |
void io_manager::reg (watcher *w, simplevec<watcher *> &queue) |
40 |
{ |
41 |
if (!iom_valid) |
42 |
abort (); |
43 |
|
44 |
if (!w->active) |
45 |
{ |
46 |
queue.push_back (w); |
47 |
w->active = queue.size (); |
48 |
} |
49 |
} |
50 |
|
51 |
template<class watcher> |
52 |
void io_manager::unreg (watcher *w, simplevec<watcher *> &queue) |
53 |
{ |
54 |
if (!iom_valid) |
55 |
return; |
56 |
|
57 |
if (w->active) |
58 |
{ |
59 |
queue [w->active - 1] = 0; |
60 |
w->active = 0; |
61 |
} |
62 |
} |
63 |
|
64 |
#if IOM_TIME |
65 |
void time_watcher::trigger () |
66 |
{ |
67 |
call (*this); |
68 |
|
69 |
iom.reg (this); |
70 |
} |
71 |
|
72 |
void io_manager::reg (time_watcher *w) { reg (w, tw); } |
73 |
void io_manager::unreg (time_watcher *w) { unreg (w, tw); } |
74 |
#endif |
75 |
|
76 |
#if IOM_IO |
77 |
void io_manager::reg (io_watcher *w) { reg (w, iow); } |
78 |
void io_manager::unreg (io_watcher *w) { unreg (w, iow); } |
79 |
#endif |
80 |
|
81 |
#if IOM_CHECK |
82 |
void io_manager::reg (check_watcher *w) { reg (w, cw); } |
83 |
void io_manager::unreg (check_watcher *w) { unreg (w, cw); } |
84 |
#endif |
85 |
|
86 |
#if IOM_IDLE |
87 |
void io_manager::reg (idle_watcher *w) { reg (w, iw); } |
88 |
void io_manager::unreg (idle_watcher *w) { unreg (w, iw); } |
89 |
#endif |
90 |
|
91 |
#if IOM_TIME |
92 |
inline void set_now (void) |
93 |
{ |
94 |
struct timeval tv; |
95 |
|
96 |
gettimeofday (&tv, 0); |
97 |
|
98 |
NOW = (tstamp)tv.tv_sec + (tstamp)tv.tv_usec / 1000000; |
99 |
#endif |
100 |
} |
101 |
|
102 |
void io_manager::loop () |
103 |
{ |
104 |
#if IOM_TIME |
105 |
set_now (); |
106 |
#endif |
107 |
|
108 |
for (;;) |
109 |
{ |
110 |
struct timeval *to = 0; |
111 |
struct timeval tval; |
112 |
|
113 |
#if IOM_IDLE |
114 |
if (iw.size ()) |
115 |
{ |
116 |
tval.tv_sec = 0; |
117 |
tval.tv_usec = 0; |
118 |
to = &tval; |
119 |
} |
120 |
else |
121 |
#endif |
122 |
{ |
123 |
#if IOM_TIME |
124 |
time_watcher *next; |
125 |
|
126 |
for (;;) |
127 |
{ |
128 |
next = tw[0]; // the first time-watcher must exist at ALL times |
129 |
|
130 |
for (int i = tw.size (); i--; ) |
131 |
if (!tw[i]) |
132 |
tw.erase_unordered (i); |
133 |
else if (tw[i]->at < next->at) |
134 |
next = tw[i]; |
135 |
|
136 |
if (next->at > NOW) |
137 |
{ |
138 |
if (next != tw[0]) |
139 |
{ |
140 |
double diff = next->at - NOW; |
141 |
tval.tv_sec = (int)diff; |
142 |
tval.tv_usec = (int)((diff - tval.tv_sec) * 1000000); |
143 |
to = &tval; |
144 |
} |
145 |
break; |
146 |
} |
147 |
else if (next->at >= 0) |
148 |
{ |
149 |
unreg (next); |
150 |
next->call (*next); |
151 |
} |
152 |
} |
153 |
#endif |
154 |
} |
155 |
|
156 |
#if IOM_CHECK |
157 |
for (int i = cw.size (); i--; ) |
158 |
if (!cw[i]) |
159 |
cw.erase_unordered (i); |
160 |
else |
161 |
cw[i]->call (*cw[i]); |
162 |
#endif |
163 |
|
164 |
#if IOM_IO |
165 |
fd_set rfd, wfd, efd; |
166 |
|
167 |
FD_ZERO (&rfd); |
168 |
FD_ZERO (&wfd); |
169 |
|
170 |
int fds = 0; |
171 |
|
172 |
for (io_watcher **i = iow.end (); i-- > iow.begin (); ) |
173 |
if (*i) |
174 |
{ |
175 |
if ((*i)->events & EVENT_READ ) FD_SET ((*i)->fd, &rfd); |
176 |
if ((*i)->events & EVENT_WRITE) FD_SET ((*i)->fd, &wfd); |
177 |
|
178 |
if ((*i)->fd >= fds) fds = (*i)->fd + 1; |
179 |
} |
180 |
|
181 |
if (!to && !fds) //TODO: also check idle_watchers and check_watchers |
182 |
break; // no events |
183 |
|
184 |
fds = select (fds, &rfd, &wfd, &efd, to); |
185 |
# if IOM_TIME |
186 |
set_now (); |
187 |
# endif |
188 |
|
189 |
if (fds > 0) |
190 |
for (int i = iow.size (); i--; ) |
191 |
if (!iow[i]) |
192 |
iow.erase_unordered (i); |
193 |
else |
194 |
{ |
195 |
short revents = iow[i]->events; |
196 |
|
197 |
if (!FD_ISSET (iow[i]->fd, &rfd)) revents &= ~EVENT_READ; |
198 |
if (!FD_ISSET (iow[i]->fd, &wfd)) revents &= ~EVENT_WRITE; |
199 |
|
200 |
if (revents) |
201 |
iow[i]->call (*iow[i], revents); |
202 |
} |
203 |
else if (fds < 0 && errno != EINTR) |
204 |
{ |
205 |
perror ("Error while waiting for I/O or time event"); |
206 |
abort (); |
207 |
} |
208 |
#if IOM_IDLE |
209 |
else |
210 |
for (int i = iw.size (); i--; ) |
211 |
if (!iw[i]) |
212 |
iw.erase_unordered (i); |
213 |
else |
214 |
iw[i]->call (*iw[i]); |
215 |
#endif |
216 |
|
217 |
#elif IOM_TIME |
218 |
if (!to) |
219 |
break; |
220 |
|
221 |
select (0, 0, 0, 0, &to); |
222 |
set_now (); |
223 |
#else |
224 |
break; |
225 |
#endif |
226 |
} |
227 |
} |
228 |
|
229 |
// this is a dummy time watcher to ensure that the first |
230 |
// time watcher is _always_ valid, this gets rid of a lot |
231 |
// of null-pointer-checks |
232 |
static struct tw0 : time_watcher { |
233 |
void cb (time_watcher &w) |
234 |
{ |
235 |
// should never get called |
236 |
// reached end-of-time, or tstamp has a bogus definition :) |
237 |
abort (); |
238 |
} |
239 |
|
240 |
tw0() |
241 |
: time_watcher (this, &tw0::cb) |
242 |
{ } |
243 |
} tw0; |
244 |
|
245 |
io_manager::io_manager () |
246 |
{ |
247 |
iom_valid = true; |
248 |
|
249 |
#if IOM_TIME |
250 |
set_now (); |
251 |
|
252 |
tw0.start (TSTAMP_MAX); |
253 |
#endif |
254 |
} |
255 |
|
256 |
io_manager::~io_manager () |
257 |
{ |
258 |
iom_valid = false; |
259 |
} |
260 |
|