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 int aeApiResize(aeEventLoop *eventLoop, int setsize) { 52 /* Just ensure we have enough room in the fd_set type. */ 53 if (setsize >= FD_SETSIZE) return -1; 54 return 0; 55 } 56 57 static void aeApiFree(aeEventLoop *eventLoop) { 58 zfree(eventLoop->apidata); 59 } 60 61 static int aeApiAddEvent(aeEventLoop *eventLoop, int fd, int mask) { 62 aeApiState *state = eventLoop->apidata; 63 64 if (mask & AE_READABLE) FD_SET(fd,&state->rfds); 65 if (mask & AE_WRITABLE) FD_SET(fd,&state->wfds); 66 return 0; 67 } 68 69 static void aeApiDelEvent(aeEventLoop *eventLoop, int fd, int mask) { 70 aeApiState *state = eventLoop->apidata; 71 72 if (mask & AE_READABLE) FD_CLR(fd,&state->rfds); 73 if (mask & AE_WRITABLE) FD_CLR(fd,&state->wfds); 74 } 75 76 static int aeApiPoll(aeEventLoop *eventLoop, struct timeval *tvp) { 77 aeApiState *state = eventLoop->apidata; 78 int retval, j, numevents = 0; 79 80 memcpy(&state->_rfds,&state->rfds,sizeof(fd_set)); 81 memcpy(&state->_wfds,&state->wfds,sizeof(fd_set)); 82 83 retval = select(eventLoop->maxfd+1, 84 &state->_rfds,&state->_wfds,NULL,tvp); 85 if (retval > 0) { 86 for (j = 0; j <= eventLoop->maxfd; j++) { 87 int mask = 0; 88 aeFileEvent *fe = &eventLoop->events[j]; 89 90 if (fe->mask == AE_NONE) continue; 91 if (fe->mask & AE_READABLE && FD_ISSET(j,&state->_rfds)) 92 mask |= AE_READABLE; 93 if (fe->mask & AE_WRITABLE && FD_ISSET(j,&state->_wfds)) 94 mask |= AE_WRITABLE; 95 eventLoop->fired[numevents].fd = j; 96 eventLoop->fired[numevents].mask = mask; 97 numevents++; 98 } 99 } 100 return numevents; 101 } 102 103 static char *aeApiName(void) { 104 return "select"; 105 } 106