| 1 | /* A simple event-driven programming library. Originally I wrote this code |
| 2 | * for the Jim's event-loop (Jim is a Tcl interpreter) but later translated |
| 3 | * it in form of a library for easy reuse. |
| 4 | * |
| 5 | * Copyright (c) 2006-2009, Salvatore Sanfilippo <antirez at gmail dot com> |
| 6 | * All rights reserved. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions are met: |
| 10 | * |
| 11 | * * Redistributions of source code must retain the above copyright notice, |
| 12 | * this list of conditions and the following disclaimer. |
| 13 | * * Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * * Neither the name of Redis nor the names of its contributors may be used |
| 17 | * to endorse or promote products derived from this software without |
| 18 | * specific prior written permission. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| 21 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| 24 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 25 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 26 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 29 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 30 | * POSSIBILITY OF SUCH DAMAGE. |
| 31 | */ |
| 32 | |
| 33 | #include <stdio.h> |
| 34 | #include <sys/time.h> |
| 35 | #include <sys/types.h> |
| 36 | #include <unistd.h> |
| 37 | #include <stdlib.h> |
| 38 | |
| 39 | #include "ae.h" |
| 40 | #include "zmalloc.h" |
| 41 | #include "config.h" |
| 42 | |
| 43 | /* Include the best multiplexing layer supported by this system. |
| 44 | * The following should be ordered by performances, descending. */ |
| 45 | #ifdef HAVE_EPOLL |
| 46 | #include "ae_epoll.c" |
| 47 | #else |
| 48 | #ifdef HAVE_KQUEUE |
| 49 | #include "ae_kqueue.c" |
| 50 | #else |
| 51 | #include "ae_select.c" |
| 52 | #endif |
| 53 | #endif |
| 54 | |
| 55 | aeEventLoop *aeCreateEventLoop(void) { |
| 56 | aeEventLoop *eventLoop; |
| 57 | int i; |
| 58 | |
| 59 | eventLoop = zmalloc(sizeof(*eventLoop)); |
| 60 | if (!eventLoop) return NULL; |
| 61 | eventLoop->timeEventHead = NULL; |
| 62 | eventLoop->timeEventNextId = 0; |
| 63 | eventLoop->stop = 0; |
| 64 | eventLoop->maxfd = -1; |
| 65 | if (aeApiCreate(eventLoop) == -1) { |
| 66 | zfree(eventLoop); |
| 67 | return NULL; |
| 68 | } |
| 69 | /* Events with mask == AE_NONE are not set. So let's initialize the |
| 70 | * vector with it. */ |
| 71 | for (i = 0; i < AE_SETSIZE; i++) |
| 72 | eventLoop->events[i].mask = AE_NONE; |
| 73 | return eventLoop; |
| 74 | } |
| 75 | |
| 76 | void aeDeleteEventLoop(aeEventLoop *eventLoop) { |
| 77 | aeApiFree(eventLoop); |
| 78 | zfree(eventLoop); |
| 79 | } |
| 80 | |
| 81 | void aeStop(aeEventLoop *eventLoop) { |
| 82 | eventLoop->stop = 1; |
| 83 | } |
| 84 | |
| 85 | int aeCreateFileEvent(aeEventLoop *eventLoop, int fd, int mask, |
| 86 | aeFileProc *proc, void *clientData) |
| 87 | { |
| 88 | if (fd >= AE_SETSIZE) return AE_ERR; |
| 89 | aeFileEvent *fe = &eventLoop->events[fd]; |
| 90 | |
| 91 | if (aeApiAddEvent(eventLoop, fd, mask) == -1) |
| 92 | return AE_ERR; |
| 93 | fe->mask |= mask; |
| 94 | if (mask & AE_READABLE) fe->rfileProc = proc; |
| 95 | if (mask & AE_WRITABLE) fe->wfileProc = proc; |
| 96 | if (mask & AE_EXCEPTION) fe->efileProc = proc; |
| 97 | fe->clientData = clientData; |
| 98 | if (fd > eventLoop->maxfd) |
| 99 | eventLoop->maxfd = fd; |
| 100 | return AE_OK; |
| 101 | } |
| 102 | |
| 103 | void aeDeleteFileEvent(aeEventLoop *eventLoop, int fd, int mask) |
| 104 | { |
| 105 | if (fd >= AE_SETSIZE) return; |
| 106 | aeFileEvent *fe = &eventLoop->events[fd]; |
| 107 | |
| 108 | if (fe->mask == AE_NONE) return; |
| 109 | fe->mask = fe->mask & (~mask); |
| 110 | if (fd == eventLoop->maxfd && fe->mask == AE_NONE) { |
| 111 | /* Update the max fd */ |
| 112 | int j; |
| 113 | |
| 114 | for (j = eventLoop->maxfd-1; j >= 0; j--) |
| 115 | if (eventLoop->events[j].mask != AE_NONE) break; |
| 116 | eventLoop->maxfd = j; |
| 117 | } |
| 118 | aeApiDelEvent(eventLoop, fd, mask); |
| 119 | } |
| 120 | |
| 121 | static void aeGetTime(long *seconds, long *milliseconds) |
| 122 | { |
| 123 | struct timeval tv; |
| 124 | |
| 125 | gettimeofday(&tv, NULL); |
| 126 | *seconds = tv.tv_sec; |
| 127 | *milliseconds = tv.tv_usec/1000; |
| 128 | } |
| 129 | |
| 130 | static void aeAddMillisecondsToNow(long long milliseconds, long *sec, long *ms) { |
| 131 | long cur_sec, cur_ms, when_sec, when_ms; |
| 132 | |
| 133 | aeGetTime(&cur_sec, &cur_ms); |
| 134 | when_sec = cur_sec + milliseconds/1000; |
| 135 | when_ms = cur_ms + milliseconds%1000; |
| 136 | if (when_ms >= 1000) { |
| 137 | when_sec ++; |
| 138 | when_ms -= 1000; |
| 139 | } |
| 140 | *sec = when_sec; |
| 141 | *ms = when_ms; |
| 142 | } |
| 143 | |
| 144 | long long aeCreateTimeEvent(aeEventLoop *eventLoop, long long milliseconds, |
| 145 | aeTimeProc *proc, void *clientData, |
| 146 | aeEventFinalizerProc *finalizerProc) |
| 147 | { |
| 148 | long long id = eventLoop->timeEventNextId++; |
| 149 | aeTimeEvent *te; |
| 150 | |
| 151 | te = zmalloc(sizeof(*te)); |
| 152 | if (te == NULL) return AE_ERR; |
| 153 | te->id = id; |
| 154 | aeAddMillisecondsToNow(milliseconds,&te->when_sec,&te->when_ms); |
| 155 | te->timeProc = proc; |
| 156 | te->finalizerProc = finalizerProc; |
| 157 | te->clientData = clientData; |
| 158 | te->next = eventLoop->timeEventHead; |
| 159 | eventLoop->timeEventHead = te; |
| 160 | return id; |
| 161 | } |
| 162 | |
| 163 | int aeDeleteTimeEvent(aeEventLoop *eventLoop, long long id) |
| 164 | { |
| 165 | aeTimeEvent *te, *prev = NULL; |
| 166 | |
| 167 | te = eventLoop->timeEventHead; |
| 168 | while(te) { |
| 169 | if (te->id == id) { |
| 170 | if (prev == NULL) |
| 171 | eventLoop->timeEventHead = te->next; |
| 172 | else |
| 173 | prev->next = te->next; |
| 174 | if (te->finalizerProc) |
| 175 | te->finalizerProc(eventLoop, te->clientData); |
| 176 | zfree(te); |
| 177 | return AE_OK; |
| 178 | } |
| 179 | prev = te; |
| 180 | te = te->next; |
| 181 | } |
| 182 | return AE_ERR; /* NO event with the specified ID found */ |
| 183 | } |
| 184 | |
| 185 | /* Search the first timer to fire. |
| 186 | * This operation is useful to know how many time the select can be |
| 187 | * put in sleep without to delay any event. |
| 188 | * If there are no timers NULL is returned. |
| 189 | * |
| 190 | * Note that's O(N) since time events are unsorted. |
| 191 | * Possible optimizations (not needed by Redis so far, but...): |
| 192 | * 1) Insert the event in order, so that the nearest is just the head. |
| 193 | * Much better but still insertion or deletion of timers is O(N). |
| 194 | * 2) Use a skiplist to have this operation as O(1) and insertion as O(log(N)). |
| 195 | */ |
| 196 | static aeTimeEvent *aeSearchNearestTimer(aeEventLoop *eventLoop) |
| 197 | { |
| 198 | aeTimeEvent *te = eventLoop->timeEventHead; |
| 199 | aeTimeEvent *nearest = NULL; |
| 200 | |
| 201 | while(te) { |
| 202 | if (!nearest || te->when_sec < nearest->when_sec || |
| 203 | (te->when_sec == nearest->when_sec && |
| 204 | te->when_ms < nearest->when_ms)) |
| 205 | nearest = te; |
| 206 | te = te->next; |
| 207 | } |
| 208 | return nearest; |
| 209 | } |
| 210 | |
| 211 | /* Process time events */ |
| 212 | static int processTimeEvents(aeEventLoop *eventLoop) { |
| 213 | int processed = 0; |
| 214 | aeTimeEvent *te; |
| 215 | long long maxId; |
| 216 | |
| 217 | te = eventLoop->timeEventHead; |
| 218 | maxId = eventLoop->timeEventNextId-1; |
| 219 | while(te) { |
| 220 | long now_sec, now_ms; |
| 221 | long long id; |
| 222 | |
| 223 | if (te->id > maxId) { |
| 224 | te = te->next; |
| 225 | continue; |
| 226 | } |
| 227 | aeGetTime(&now_sec, &now_ms); |
| 228 | if (now_sec > te->when_sec || |
| 229 | (now_sec == te->when_sec && now_ms >= te->when_ms)) |
| 230 | { |
| 231 | int retval; |
| 232 | |
| 233 | id = te->id; |
| 234 | retval = te->timeProc(eventLoop, id, te->clientData); |
| 235 | processed++; |
| 236 | /* After an event is processed our time event list may |
| 237 | * no longer be the same, so we restart from head. |
| 238 | * Still we make sure to don't process events registered |
| 239 | * by event handlers itself in order to don't loop forever. |
| 240 | * To do so we saved the max ID we want to handle. |
| 241 | * |
| 242 | * FUTURE OPTIMIZATIONS: |
| 243 | * Note that this is NOT great algorithmically. Redis uses |
| 244 | * a single time event so it's not a problem but the right |
| 245 | * way to do this is to add the new elements on head, and |
| 246 | * to flag deleted elements in a special way for later |
| 247 | * deletion (putting references to the nodes to delete into |
| 248 | * another linked list). */ |
| 249 | if (retval != AE_NOMORE) { |
| 250 | aeAddMillisecondsToNow(retval,&te->when_sec,&te->when_ms); |
| 251 | } else { |
| 252 | aeDeleteTimeEvent(eventLoop, id); |
| 253 | } |
| 254 | te = eventLoop->timeEventHead; |
| 255 | } else { |
| 256 | te = te->next; |
| 257 | } |
| 258 | } |
| 259 | return processed; |
| 260 | } |
| 261 | |
| 262 | /* Process every pending time event, then every pending file event |
| 263 | * (that may be registered by time event callbacks just processed). |
| 264 | * Without special flags the function sleeps until some file event |
| 265 | * fires, or when the next time event occurrs (if any). |
| 266 | * |
| 267 | * If flags is 0, the function does nothing and returns. |
| 268 | * if flags has AE_ALL_EVENTS set, all the kind of events are processed. |
| 269 | * if flags has AE_FILE_EVENTS set, file events are processed. |
| 270 | * if flags has AE_TIME_EVENTS set, time events are processed. |
| 271 | * if flags has AE_DONT_WAIT set the function returns ASAP until all |
| 272 | * the events that's possible to process without to wait are processed. |
| 273 | * |
| 274 | * The function returns the number of events processed. */ |
| 275 | int aeProcessEvents(aeEventLoop *eventLoop, int flags) |
| 276 | { |
| 277 | int processed = 0, numevents; |
| 278 | |
| 279 | /* Nothing to do? return ASAP */ |
| 280 | if (!(flags & AE_TIME_EVENTS) && !(flags & AE_FILE_EVENTS)) return 0; |
| 281 | |
| 282 | /* Note that we want call select() even if there are no |
| 283 | * file events to process as long as we want to process time |
| 284 | * events, in order to sleep until the next time event is ready |
| 285 | * to fire. */ |
| 286 | if (eventLoop->maxfd != -1 || |
| 287 | ((flags & AE_TIME_EVENTS) && !(flags & AE_DONT_WAIT))) { |
| 288 | int j; |
| 289 | aeTimeEvent *shortest = NULL; |
| 290 | struct timeval tv, *tvp; |
| 291 | |
| 292 | if (flags & AE_TIME_EVENTS && !(flags & AE_DONT_WAIT)) |
| 293 | shortest = aeSearchNearestTimer(eventLoop); |
| 294 | if (shortest) { |
| 295 | long now_sec, now_ms; |
| 296 | |
| 297 | /* Calculate the time missing for the nearest |
| 298 | * timer to fire. */ |
| 299 | aeGetTime(&now_sec, &now_ms); |
| 300 | tvp = &tv; |
| 301 | tvp->tv_sec = shortest->when_sec - now_sec; |
| 302 | if (shortest->when_ms < now_ms) { |
| 303 | tvp->tv_usec = ((shortest->when_ms+1000) - now_ms)*1000; |
| 304 | tvp->tv_sec --; |
| 305 | } else { |
| 306 | tvp->tv_usec = (shortest->when_ms - now_ms)*1000; |
| 307 | } |
| 308 | if (tvp->tv_sec < 0) tvp->tv_sec = 0; |
| 309 | if (tvp->tv_usec < 0) tvp->tv_usec = 0; |
| 310 | } else { |
| 311 | /* If we have to check for events but need to return |
| 312 | * ASAP because of AE_DONT_WAIT we need to se the timeout |
| 313 | * to zero */ |
| 314 | if (flags & AE_DONT_WAIT) { |
| 315 | tv.tv_sec = tv.tv_usec = 0; |
| 316 | tvp = &tv; |
| 317 | } else { |
| 318 | /* Otherwise we can block */ |
| 319 | tvp = NULL; /* wait forever */ |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | numevents = aeApiPoll(eventLoop, tvp); |
| 324 | for (j = 0; j < numevents; j++) { |
| 325 | aeFileEvent *fe = &eventLoop->events[eventLoop->fired[j].fd]; |
| 326 | int mask = eventLoop->fired[j].mask; |
| 327 | int fd = eventLoop->fired[j].fd; |
| 328 | |
| 329 | /* note the fe->mask & mask & ... code: maybe an already processed |
| 330 | * event removed an element that fired and we still didn't |
| 331 | * processed, so we check if the event is still valid. */ |
| 332 | if (fe->mask & mask & AE_READABLE) |
| 333 | fe->rfileProc(eventLoop,fd,fe->clientData,mask); |
| 334 | if (fe->mask & mask & AE_WRITABLE && fe->wfileProc != fe->rfileProc) |
| 335 | fe->wfileProc(eventLoop,fd,fe->clientData,mask); |
| 336 | if (fe->mask & mask & AE_EXCEPTION && |
| 337 | fe->efileProc != fe->wfileProc && |
| 338 | fe->efileProc != fe->rfileProc) |
| 339 | fe->efileProc(eventLoop,fd,fe->clientData,mask); |
| 340 | processed++; |
| 341 | } |
| 342 | } |
| 343 | /* Check time events */ |
| 344 | if (flags & AE_TIME_EVENTS) |
| 345 | processed += processTimeEvents(eventLoop); |
| 346 | |
| 347 | return processed; /* return the number of processed file/time events */ |
| 348 | } |
| 349 | |
| 350 | /* Wait for millseconds until the given file descriptor becomes |
| 351 | * writable/readable/exception */ |
| 352 | int aeWait(int fd, int mask, long long milliseconds) { |
| 353 | struct timeval tv; |
| 354 | fd_set rfds, wfds, efds; |
| 355 | int retmask = 0, retval; |
| 356 | |
| 357 | tv.tv_sec = milliseconds/1000; |
| 358 | tv.tv_usec = (milliseconds%1000)*1000; |
| 359 | FD_ZERO(&rfds); |
| 360 | FD_ZERO(&wfds); |
| 361 | FD_ZERO(&efds); |
| 362 | |
| 363 | if (mask & AE_READABLE) FD_SET(fd,&rfds); |
| 364 | if (mask & AE_WRITABLE) FD_SET(fd,&wfds); |
| 365 | if (mask & AE_EXCEPTION) FD_SET(fd,&efds); |
| 366 | if ((retval = select(fd+1, &rfds, &wfds, &efds, &tv)) > 0) { |
| 367 | if (FD_ISSET(fd,&rfds)) retmask |= AE_READABLE; |
| 368 | if (FD_ISSET(fd,&wfds)) retmask |= AE_WRITABLE; |
| 369 | if (FD_ISSET(fd,&efds)) retmask |= AE_EXCEPTION; |
| 370 | return retmask; |
| 371 | } else { |
| 372 | return retval; |
| 373 | } |
| 374 | } |
| 375 | |
| 376 | void aeMain(aeEventLoop *eventLoop) { |
| 377 | eventLoop->stop = 0; |
| 378 | while (!eventLoop->stop) |
| 379 | aeProcessEvents(eventLoop, AE_ALL_EVENTS); |
| 380 | } |
| 381 | |
| 382 | char *aeGetApiName(void) { |
| 383 | return aeApiName(); |
| 384 | } |