src/IOEngine_select.c

   1 /* IOEngine_select.c - TransparentIRC 0.1
   2  * Copyright (C) 2011-2012  Philipp Kreil (pk910)
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 #include "IOEngine.h"
  18 #include "IOHandler.h"
  19
  20 static int engine_select_init() {
  21     /* empty */
  22     return 1;
  23 }
  24
  25 static void engine_select_add(struct IODescriptor *iofd) {
  26     /* empty */
  27 }
  28
  29 static void engine_select_remove(struct IODescriptor *iofd) {
  30     /* empty */
  31 }
  32
  33 static void engine_select_update(struct IODescriptor *iofd) {
  34     /* empty */
  35 }
  36
  37 static void engine_select_loop(struct timeval *timeout) {
  38     fd_set read_fds;
  39     fd_set write_fds;
  40     unsigned int fds_size = 0;
  41     struct IODescriptor *iofd, *tmp_iofd;
  42     struct timeval now, tdiff;
  43     int select_result;
  44
  45     gettimeofday(&now, NULL);
  46
  47     //clear fds
  48     FD_ZERO(&read_fds);
  49     FD_ZERO(&write_fds);
  50
  51     for(iofd = first_descriptor; iofd; iofd = tmp_iofd) {
  52         tmp_iofd = iofd->next;
  53         if(iofd->type == IOTYPE_SERVER || iofd->type == IOTYPE_CLIENT || iofd->type == IOTYPE_STDIN) {
  54             if(iofd->fd > fds_size)
  55                 fds_size = iofd->fd;
  56             FD_SET(iofd->fd, &read_fds);
  57             if(iohandler_wants_writes(iofd))
  58                 FD_SET(iofd->fd, &write_fds);
  59         }
  60         if(iofd->type == IOTYPE_TIMER || iofd->timeout.tv_sec || iofd->timeout.tv_usec) {
  61             tdiff.tv_sec = iofd->timeout.tv_sec - now.tv_sec;
  62             tdiff.tv_usec = iofd->timeout.tv_usec - now.tv_usec;
  63
  64             if(tdiff.tv_sec < 0 || (tdiff.tv_sec == 0 && tdiff.tv_usec <= 0)) {
  65                 //exec timer
  66                 iohandler_events(iofd, 0, 0);
  67                 if(iofd->type == IOTYPE_TIMER)
  68                     iohandler_close(iofd);
  69                 continue;
  70             } else if(tdiff.tv_usec < 0) {
  71                 tdiff.tv_sec--;
  72                 tdiff.tv_usec += 1000000; //1 sec
  73             }
  74             if(timeval_is_smaler((&tdiff), timeout)) {
  75                 timeout->tv_sec = tdiff.tv_sec;
  76                 timeout->tv_usec = tdiff.tv_usec;
  77             }
  78         }
  79     }
  80
  81     //select system call
  82     select_result = select(fds_size + 1, &read_fds, &write_fds, NULL, timeout);
  83
  84     if (select_result < 0) {
  85         if (errno != EINTR) {
  86             //hard fail
  87             return;
  88         }
  89     }
  90
  91     gettimeofday(&now, NULL);
  92
  93     //check all descriptors
  94     for(iofd = first_descriptor; iofd; iofd = tmp_iofd) {
  95         tmp_iofd = iofd->next;
  96         if(iofd->type == IOTYPE_SERVER || iofd->type == IOTYPE_CLIENT || iofd->type == IOTYPE_STDIN) {
  97             if(FD_ISSET(iofd->fd, &read_fds) || FD_ISSET(iofd->fd, &write_fds)) {
  98                 iohandler_events(iofd, FD_ISSET(iofd->fd, &read_fds), FD_ISSET(iofd->fd, &write_fds));
  99                 continue;
 100             }
 101         }
 102         if(iofd->type == IOTYPE_TIMER || iofd->timeout.tv_sec || iofd->timeout.tv_usec) {
 103             tdiff.tv_sec = iofd->timeout.tv_sec - now.tv_sec;
 104             tdiff.tv_usec = iofd->timeout.tv_usec - now.tv_usec;
 105
 106             if(tdiff.tv_sec < 0 || (tdiff.tv_sec == 0 && tdiff.tv_usec <= 0)) {
 107                 //exec timer
 108                 iohandler_events(iofd, 0, 0);
 109                 if(iofd->type == IOTYPE_TIMER)
 110                     iohandler_close(iofd);
 111                 continue;
 112             }
 113         }
 114     }
 115 }
 116
 117 static void engine_select_cleanup() {
 118     /* empty */
 119 }
 120
 121 struct IOEngine engine_select = {
 122     .name = "select",
 123     .init = engine_select_init,
 124     .add = engine_select_add,
 125     .remove = engine_select_remove,
 126     .update = engine_select_update,
 127     .loop = engine_select_loop,
 128     .cleanup = engine_select_cleanup,
 129 };