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/cvs/libev/ev_select.c
Revision: 1.14
Committed: Tue Nov 6 00:10:04 2007 UTC (16 years, 6 months ago) by root
Content type: text/plain
Branch: MAIN
Changes since 1.13: +38 -37 lines
Log Message:
better error handling

File Contents

# Content
1 /*
2 * libev select fd activity backend
3 *
4 * Copyright (c) 2007 Marc Alexander Lehmann <libev@schmorp.de>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are
9 * met:
10 *
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 *
14 * * Redistributions in binary form must reproduce the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer in the documentation and/or other materials provided
17 * with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /* for broken bsd's */
33 #include <sys/time.h>
34 #include <sys/types.h>
35 #include <unistd.h>
36
37 /* for unix systems */
38 #ifndef WIN32
39 # include <sys/select.h>
40 #endif
41
42 #include <string.h>
43 #include <inttypes.h>
44
45 static void
46 select_modify (EV_P_ int fd, int oev, int nev)
47 {
48 int offs = fd >> 3;
49 int mask = 1 << (fd & 7);
50
51 if (oev == nev)
52 return;
53
54 if (vec_max < (fd >> 5) + 1)
55 {
56 int new_max = (fd >> 5) + 1;
57
58 vec_ri = (unsigned char *)ev_realloc (vec_ri, new_max * 4);
59 vec_ro = (unsigned char *)ev_realloc (vec_ro, new_max * 4); /* could free/malloc */
60 vec_wi = (unsigned char *)ev_realloc (vec_wi, new_max * 4);
61 vec_wo = (unsigned char *)ev_realloc (vec_wo, new_max * 4); /* could free/malloc */
62
63 for (; vec_max < new_max; ++vec_max)
64 ((uint32_t *)vec_ri)[vec_max] =
65 ((uint32_t *)vec_wi)[vec_max] = 0;
66 }
67
68 vec_ri [offs] |= mask;
69 if (!(nev & EV_READ))
70 vec_ri [offs] &= ~mask;
71
72 vec_wi [offs] |= mask;
73 if (!(nev & EV_WRITE))
74 vec_wi [offs] &= ~mask;
75 }
76
77 static void
78 select_poll (EV_P_ ev_tstamp timeout)
79 {
80 int word, offs;
81 struct timeval tv;
82 int res;
83
84 memcpy (vec_ro, vec_ri, vec_max * 4);
85 memcpy (vec_wo, vec_wi, vec_max * 4);
86
87 tv.tv_sec = (long)timeout;
88 tv.tv_usec = (long)((timeout - (ev_tstamp)tv.tv_sec) * 1e6);
89
90 res = select (vec_max * 32, (fd_set *)vec_ro, (fd_set *)vec_wo, 0, &tv);
91
92 if (res < 0)
93 {
94 if (errno == EBADF)
95 fd_ebadf (EV_A);
96 else if (errno == ENOMEM && !syserr_cb)
97 fd_enomem (EV_A);
98 else if (errno != EINTR)
99 syserr ();
100
101 return;
102 }
103
104 for (word = vec_max; word--; )
105 {
106 if (((uint32_t *)vec_ro) [word] | ((uint32_t *)vec_wo) [word])
107 for (offs = 4; offs--; )
108 {
109 int idx = word * 4 + offs;
110 unsigned char byte_r = vec_ro [idx];
111 unsigned char byte_w = vec_wo [idx];
112 int bit;
113
114 if (byte_r | byte_w)
115 for (bit = 8; bit--; )
116 {
117 int events = 0;
118 events |= byte_r & (1 << bit) ? EV_READ : 0;
119 events |= byte_w & (1 << bit) ? EV_WRITE : 0;
120
121 if (events)
122 fd_event (EV_A_ idx * 8 + bit, events);
123 }
124 }
125 }
126 }
127
128 static int
129 select_init (EV_P_ int flags)
130 {
131 method_fudge = 1e-2; /* needed to compensate for select returning early, very conservative */
132 method_modify = select_modify;
133 method_poll = select_poll;
134
135 vec_max = 0;
136 vec_ri = 0;
137 vec_ri = 0;
138 vec_wo = 0;
139 vec_wo = 0;
140
141 return EVMETHOD_SELECT;
142 }
143
144 static void
145 select_destroy (EV_P)
146 {
147 ev_free (vec_ri);
148 ev_free (vec_ro);
149 ev_free (vec_wi);
150 ev_free (vec_wo);
151 }
152
153