src/ae_select.c

   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 <string.h>
  33
  34 typedef struct aeApiState {
  35     fd_set rfds, wfds;
  36     /* We need to have a copy of the fd sets as it's not safe to reuse
  37      * FD sets after select(). */
  38     fd_set _rfds, _wfds;
  39 } aeApiState;
  40
  41 static int aeApiCreate(aeEventLoop *eventLoop) {
  42     aeApiState *state = zmalloc(sizeof(aeApiState));
  43
  44     if (!state) return -1;
  45     FD_ZERO(&state->rfds);
  46     FD_ZERO(&state->wfds);
  47     eventLoop->apidata = state;
  48     return 0;
  49 }
  50
  51 static void aeApiFree(aeEventLoop *eventLoop) {
  52     zfree(eventLoop->apidata);
  53 }
  54
  55 static int aeApiAddEvent(aeEventLoop *eventLoop, int fd, int mask) {
  56     aeApiState *state = eventLoop->apidata;
  57
  58     if (mask & AE_READABLE) FD_SET(fd,&state->rfds);
  59     if (mask & AE_WRITABLE) FD_SET(fd,&state->wfds);
  60     return 0;
  61 }
  62
  63 static void aeApiDelEvent(aeEventLoop *eventLoop, int fd, int mask) {
  64     aeApiState *state = eventLoop->apidata;
  65
  66     if (mask & AE_READABLE) FD_CLR(fd,&state->rfds);
  67     if (mask & AE_WRITABLE) FD_CLR(fd,&state->wfds);
  68 }
  69
  70 static int aeApiPoll(aeEventLoop *eventLoop, struct timeval *tvp) {
  71     aeApiState *state = eventLoop->apidata;
  72     int retval, j, numevents = 0;
  73
  74     memcpy(&state->_rfds,&state->rfds,sizeof(fd_set));
  75     memcpy(&state->_wfds,&state->wfds,sizeof(fd_set));
  76
  77     retval = select(eventLoop->maxfd+1,
  78                 &state->_rfds,&state->_wfds,NULL,tvp);
  79     if (retval > 0) {
  80         for (j = 0; j <= eventLoop->maxfd; j++) {
  81             int mask = 0;
  82             aeFileEvent *fe = &eventLoop->events[j];
  83
  84             if (fe->mask == AE_NONE) continue;
  85             if (fe->mask & AE_READABLE && FD_ISSET(j,&state->_rfds))
  86                 mask |= AE_READABLE;
  87             if (fe->mask & AE_WRITABLE && FD_ISSET(j,&state->_wfds))
  88                 mask |= AE_WRITABLE;
  89             eventLoop->fired[numevents].fd = j;
  90             eventLoop->fired[numevents].mask = mask;
  91             numevents++;
  92         }
  93     }
  94     return numevents;
  95 }
  96
  97 static char *aeApiName(void) {
  98     return "select";
  99 }