1 /* Select()-based ae.c module.
2 *
3 * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * * Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 * * Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * * Neither the name of Redis nor the names of its contributors may be used
15 * to endorse or promote products derived from this software without
16 * specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31
32 #include <sys/select.h>
33 #include <string.h>
34
35 typedef struct aeApiState {
36 fd_set rfds, wfds;
37 /* We need to have a copy of the fd sets as it's not safe to reuse
38 * FD sets after select(). */
39 fd_set _rfds, _wfds;
40 } aeApiState;
41
aeApiCreate(aeEventLoop * eventLoop)42 static int aeApiCreate(aeEventLoop *eventLoop) {
43 aeApiState *state = zmalloc(sizeof(aeApiState));
44
45 if (!state) return -1;
46 FD_ZERO(&state->rfds);
47 FD_ZERO(&state->wfds);
48 eventLoop->apidata = state;
49 return 0;
50 }
51
aeApiResize(aeEventLoop * eventLoop,int setsize)52 static int aeApiResize(aeEventLoop *eventLoop, int setsize) {
53 /* Just ensure we have enough room in the fd_set type. */
54 if (setsize >= FD_SETSIZE) return -1;
55 return 0;
56 }
57
aeApiFree(aeEventLoop * eventLoop)58 static void aeApiFree(aeEventLoop *eventLoop) {
59 zfree(eventLoop->apidata);
60 }
61
aeApiAddEvent(aeEventLoop * eventLoop,int fd,int mask)62 static int aeApiAddEvent(aeEventLoop *eventLoop, int fd, int mask) {
63 aeApiState *state = eventLoop->apidata;
64
65 if (mask & AE_READABLE) FD_SET(fd,&state->rfds);
66 if (mask & AE_WRITABLE) FD_SET(fd,&state->wfds);
67 return 0;
68 }
69
aeApiDelEvent(aeEventLoop * eventLoop,int fd,int mask)70 static void aeApiDelEvent(aeEventLoop *eventLoop, int fd, int mask) {
71 aeApiState *state = eventLoop->apidata;
72
73 if (mask & AE_READABLE) FD_CLR(fd,&state->rfds);
74 if (mask & AE_WRITABLE) FD_CLR(fd,&state->wfds);
75 }
76
aeApiPoll(aeEventLoop * eventLoop,struct timeval * tvp)77 static int aeApiPoll(aeEventLoop *eventLoop, struct timeval *tvp) {
78 aeApiState *state = eventLoop->apidata;
79 int retval, j, numevents = 0;
80
81 memcpy(&state->_rfds,&state->rfds,sizeof(fd_set));
82 memcpy(&state->_wfds,&state->wfds,sizeof(fd_set));
83
84 retval = select(eventLoop->maxfd+1,
85 &state->_rfds,&state->_wfds,NULL,tvp);
86 if (retval > 0) {
87 for (j = 0; j <= eventLoop->maxfd; j++) {
88 int mask = 0;
89 aeFileEvent *fe = &eventLoop->events[j];
90
91 if (fe->mask == AE_NONE) continue;
92 if (fe->mask & AE_READABLE && FD_ISSET(j,&state->_rfds))
93 mask |= AE_READABLE;
94 if (fe->mask & AE_WRITABLE && FD_ISSET(j,&state->_wfds))
95 mask |= AE_WRITABLE;
96 eventLoop->fired[numevents].fd = j;
97 eventLoop->fired[numevents].mask = mask;
98 numevents++;
99 }
100 }
101 return numevents;
102 }
103
aeApiName(void)104 static char *aeApiName(void) {
105 return "select";
106 }
107