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| 1 /* | |
| 2 * Copyright (c) 2002-2004 Niels Provos <provos@citi.umich.edu> | |
| 3 * All rights reserved. | |
| 4 * | |
| 5 * Redistribution and use in source and binary forms, with or without | |
| 6 * modification, are permitted provided that the following conditions | |
| 7 * are met: | |
| 8 * 1. Redistributions of source code must retain the above copyright | |
| 9 * notice, this list of conditions and the following disclaimer. | |
| 10 * 2. Redistributions in binary form must reproduce the above copyright | |
| 11 * notice, this list of conditions and the following disclaimer in the | |
| 12 * documentation and/or other materials provided with the distribution. | |
| 13 * 3. The name of the author may not be used to endorse or promote products | |
| 14 * derived from this software without specific prior written permission. | |
| 15 * | |
| 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
| 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
| 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
| 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
| 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
| 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 26 */ | |
| 27 | |
| 28 #include <sys/types.h> | |
| 29 | |
| 30 #ifdef HAVE_CONFIG_H | |
| 31 #include "config.h" | |
| 32 #endif | |
| 33 | |
| 34 #ifdef HAVE_SYS_TIME_H | |
| 35 #include <sys/time.h> | |
| 36 #endif | |
| 37 | |
| 38 #include <errno.h> | |
| 39 #include <stdio.h> | |
| 40 #include <stdlib.h> | |
| 41 #include <string.h> | |
| 42 #ifdef HAVE_STDARG_H | |
| 43 #include <stdarg.h> | |
| 44 #endif | |
| 45 | |
| 46 #ifdef WIN32 | |
| 47 #include <winsock2.h> | |
| 48 #endif | |
| 49 | |
| 50 #include "evutil.h" | |
| 51 #include "event.h" | |
| 52 | |
| 53 /* prototypes */ | |
| 54 | |
| 55 void bufferevent_read_pressure_cb(struct evbuffer *, size_t, size_t, void *); | |
| 56 | |
| 57 static int | |
| 58 bufferevent_add(struct event *ev, int timeout) | |
| 59 { | |
| 60 struct timeval tv, *ptv = NULL; | |
| 61 | |
| 62 if (timeout) { | |
| 63 evutil_timerclear(&tv); | |
| 64 tv.tv_sec = timeout; | |
| 65 ptv = &tv; | |
| 66 } | |
| 67 | |
| 68 return (event_add(ev, ptv)); | |
| 69 } | |
| 70 | |
| 71 /* | |
| 72 * This callback is executed when the size of the input buffer changes. | |
| 73 * We use it to apply back pressure on the reading side. | |
| 74 */ | |
| 75 | |
| 76 void | |
| 77 bufferevent_read_pressure_cb(struct evbuffer *buf, size_t old, size_t now, | |
| 78 void *arg) { | |
| 79 struct bufferevent *bufev = arg; | |
| 80 /* | |
| 81 * If we are below the watermark then reschedule reading if it's | |
| 82 * still enabled. | |
| 83 */ | |
| 84 if (bufev->wm_read.high == 0 || now < bufev->wm_read.high) { | |
| 85 evbuffer_setcb(buf, NULL, NULL); | |
| 86 | |
| 87 if (bufev->enabled & EV_READ) | |
| 88 bufferevent_add(&bufev->ev_read, bufev->timeout_read); | |
| 89 } | |
| 90 } | |
| 91 | |
| 92 static void | |
| 93 bufferevent_readcb(int fd, short event, void *arg) | |
| 94 { | |
| 95 struct bufferevent *bufev = arg; | |
| 96 int res = 0; | |
| 97 short what = EVBUFFER_READ; | |
| 98 size_t len; | |
| 99 int howmuch = -1; | |
| 100 | |
| 101 if (event == EV_TIMEOUT) { | |
| 102 what |= EVBUFFER_TIMEOUT; | |
| 103 goto error; | |
| 104 } | |
| 105 | |
| 106 /* | |
| 107 * If we have a high watermark configured then we don't want to | |
| 108 * read more data than would make us reach the watermark. | |
| 109 */ | |
| 110 if (bufev->wm_read.high != 0) { | |
| 111 howmuch = bufev->wm_read.high - EVBUFFER_LENGTH(bufev->input); | |
| 112 /* we might have lowered the watermark, stop reading */ | |
| 113 if (howmuch <= 0) { | |
| 114 struct evbuffer *buf = bufev->input; | |
| 115 event_del(&bufev->ev_read); | |
| 116 evbuffer_setcb(buf, | |
| 117 bufferevent_read_pressure_cb, bufev); | |
| 118 return; | |
| 119 } | |
| 120 } | |
| 121 | |
| 122 res = evbuffer_read(bufev->input, fd, howmuch); | |
| 123 if (res == -1) { | |
| 124 if (errno == EAGAIN || errno == EINTR) | |
| 125 goto reschedule; | |
| 126 /* error case */ | |
| 127 what |= EVBUFFER_ERROR; | |
| 128 } else if (res == 0) { | |
| 129 /* eof case */ | |
| 130 what |= EVBUFFER_EOF; | |
| 131 } | |
| 132 | |
| 133 if (res <= 0) | |
| 134 goto error; | |
| 135 | |
| 136 bufferevent_add(&bufev->ev_read, bufev->timeout_read); | |
| 137 | |
| 138 /* See if this callbacks meets the water marks */ | |
| 139 len = EVBUFFER_LENGTH(bufev->input); | |
| 140 if (bufev->wm_read.low != 0 && len < bufev->wm_read.low) | |
| 141 return; | |
| 142 if (bufev->wm_read.high != 0 && len >= bufev->wm_read.high) { | |
| 143 struct evbuffer *buf = bufev->input; | |
| 144 event_del(&bufev->ev_read); | |
| 145 | |
| 146 /* Now schedule a callback for us when the buffer changes */ | |
| 147 evbuffer_setcb(buf, bufferevent_read_pressure_cb, bufev); | |
| 148 } | |
| 149 | |
| 150 /* Invoke the user callback - must always be called last */ | |
| 151 if (bufev->readcb != NULL) | |
| 152 (*bufev->readcb)(bufev, bufev->cbarg); | |
| 153 return; | |
| 154 | |
| 155 reschedule: | |
| 156 bufferevent_add(&bufev->ev_read, bufev->timeout_read); | |
| 157 return; | |
| 158 | |
| 159 error: | |
| 160 (*bufev->errorcb)(bufev, what, bufev->cbarg); | |
| 161 } | |
| 162 | |
| 163 static void | |
| 164 bufferevent_writecb(int fd, short event, void *arg) | |
| 165 { | |
| 166 struct bufferevent *bufev = arg; | |
| 167 int res = 0; | |
| 168 short what = EVBUFFER_WRITE; | |
| 169 | |
| 170 if (event == EV_TIMEOUT) { | |
| 171 what |= EVBUFFER_TIMEOUT; | |
| 172 goto error; | |
| 173 } | |
| 174 | |
| 175 if (EVBUFFER_LENGTH(bufev->output)) { | |
| 176 res = evbuffer_write(bufev->output, fd); | |
| 177 if (res == -1) { | |
| 178 #ifndef WIN32 | |
| 179 /*todo. evbuffer uses WriteFile when WIN32 is set. WIN32 system calls do not | |
| 180 *set errno. thus this error checking is not portable*/ | |
| 181 if (errno == EAGAIN || | |
| 182 errno == EINTR || | |
| 183 errno == EINPROGRESS) | |
| 184 goto reschedule; | |
| 185 /* error case */ | |
| 186 what |= EVBUFFER_ERROR; | |
| 187 | |
| 188 #else | |
| 189 goto reschedule; | |
| 190 #endif | |
| 191 | |
| 192 } else if (res == 0) { | |
| 193 /* eof case */ | |
| 194 what |= EVBUFFER_EOF; | |
| 195 } | |
| 196 if (res <= 0) | |
| 197 goto error; | |
| 198 } | |
| 199 | |
| 200 if (EVBUFFER_LENGTH(bufev->output) != 0) | |
| 201 bufferevent_add(&bufev->ev_write, bufev->timeout_write); | |
| 202 | |
| 203 /* | |
| 204 * Invoke the user callback if our buffer is drained or below the | |
| 205 * low watermark. | |
| 206 */ | |
| 207 if (bufev->writecb != NULL && | |
| 208 EVBUFFER_LENGTH(bufev->output) <= bufev->wm_write.low) | |
| 209 (*bufev->writecb)(bufev, bufev->cbarg); | |
| 210 | |
| 211 return; | |
| 212 | |
| 213 reschedule: | |
| 214 if (EVBUFFER_LENGTH(bufev->output) != 0) | |
| 215 bufferevent_add(&bufev->ev_write, bufev->timeout_write); | |
| 216 return; | |
| 217 | |
| 218 error: | |
| 219 (*bufev->errorcb)(bufev, what, bufev->cbarg); | |
| 220 } | |
| 221 | |
| 222 /* | |
| 223 * Create a new buffered event object. | |
| 224 * | |
| 225 * The read callback is invoked whenever we read new data. | |
| 226 * The write callback is invoked whenever the output buffer is drained. | |
| 227 * The error callback is invoked on a write/read error or on EOF. | |
| 228 * | |
| 229 * Both read and write callbacks maybe NULL. The error callback is not | |
| 230 * allowed to be NULL and have to be provided always. | |
| 231 */ | |
| 232 | |
| 233 struct bufferevent * | |
| 234 bufferevent_new(int fd, evbuffercb readcb, evbuffercb writecb, | |
| 235 everrorcb errorcb, void *cbarg) | |
| 236 { | |
| 237 struct bufferevent *bufev; | |
| 238 | |
| 239 if ((bufev = calloc(1, sizeof(struct bufferevent))) == NULL) | |
| 240 return (NULL); | |
| 241 | |
| 242 if ((bufev->input = evbuffer_new()) == NULL) { | |
| 243 free(bufev); | |
| 244 return (NULL); | |
| 245 } | |
| 246 | |
| 247 if ((bufev->output = evbuffer_new()) == NULL) { | |
| 248 evbuffer_free(bufev->input); | |
| 249 free(bufev); | |
| 250 return (NULL); | |
| 251 } | |
| 252 | |
| 253 event_set(&bufev->ev_read, fd, EV_READ, bufferevent_readcb, bufev); | |
| 254 event_set(&bufev->ev_write, fd, EV_WRITE, bufferevent_writecb, bufev); | |
| 255 | |
| 256 bufferevent_setcb(bufev, readcb, writecb, errorcb, cbarg); | |
| 257 | |
| 258 /* | |
| 259 * Set to EV_WRITE so that using bufferevent_write is going to | |
| 260 * trigger a callback. Reading needs to be explicitly enabled | |
| 261 * because otherwise no data will be available. | |
| 262 */ | |
| 263 bufev->enabled = EV_WRITE; | |
| 264 | |
| 265 return (bufev); | |
| 266 } | |
| 267 | |
| 268 void | |
| 269 bufferevent_setcb(struct bufferevent *bufev, | |
| 270 evbuffercb readcb, evbuffercb writecb, everrorcb errorcb, void *cbarg) | |
| 271 { | |
| 272 bufev->readcb = readcb; | |
| 273 bufev->writecb = writecb; | |
| 274 bufev->errorcb = errorcb; | |
| 275 | |
| 276 bufev->cbarg = cbarg; | |
| 277 } | |
| 278 | |
| 279 void | |
| 280 bufferevent_setfd(struct bufferevent *bufev, int fd) | |
| 281 { | |
| 282 event_del(&bufev->ev_read); | |
| 283 event_del(&bufev->ev_write); | |
| 284 | |
| 285 event_set(&bufev->ev_read, fd, EV_READ, bufferevent_readcb, bufev); | |
| 286 event_set(&bufev->ev_write, fd, EV_WRITE, bufferevent_writecb, bufev); | |
| 287 if (bufev->ev_base != NULL) { | |
| 288 event_base_set(bufev->ev_base, &bufev->ev_read); | |
| 289 event_base_set(bufev->ev_base, &bufev->ev_write); | |
| 290 } | |
| 291 | |
| 292 /* might have to manually trigger event registration */ | |
| 293 } | |
| 294 | |
| 295 int | |
| 296 bufferevent_priority_set(struct bufferevent *bufev, int priority) | |
| 297 { | |
| 298 if (event_priority_set(&bufev->ev_read, priority) == -1) | |
| 299 return (-1); | |
| 300 if (event_priority_set(&bufev->ev_write, priority) == -1) | |
| 301 return (-1); | |
| 302 | |
| 303 return (0); | |
| 304 } | |
| 305 | |
| 306 /* Closing the file descriptor is the responsibility of the caller */ | |
| 307 | |
| 308 void | |
| 309 bufferevent_free(struct bufferevent *bufev) | |
| 310 { | |
| 311 event_del(&bufev->ev_read); | |
| 312 event_del(&bufev->ev_write); | |
| 313 | |
| 314 evbuffer_free(bufev->input); | |
| 315 evbuffer_free(bufev->output); | |
| 316 | |
| 317 free(bufev); | |
| 318 } | |
| 319 | |
| 320 /* | |
| 321 * Returns 0 on success; | |
| 322 * -1 on failure. | |
| 323 */ | |
| 324 | |
| 325 int | |
| 326 bufferevent_write(struct bufferevent *bufev, const void *data, size_t size) | |
| 327 { | |
| 328 int res; | |
| 329 | |
| 330 res = evbuffer_add(bufev->output, data, size); | |
| 331 | |
| 332 if (res == -1) | |
| 333 return (res); | |
| 334 | |
| 335 /* If everything is okay, we need to schedule a write */ | |
| 336 if (size > 0 && (bufev->enabled & EV_WRITE)) | |
| 337 bufferevent_add(&bufev->ev_write, bufev->timeout_write); | |
| 338 | |
| 339 return (res); | |
| 340 } | |
| 341 | |
| 342 int | |
| 343 bufferevent_write_buffer(struct bufferevent *bufev, struct evbuffer *buf) | |
| 344 { | |
| 345 int res; | |
| 346 | |
| 347 res = bufferevent_write(bufev, buf->buffer, buf->off); | |
| 348 if (res != -1) | |
| 349 evbuffer_drain(buf, buf->off); | |
| 350 | |
| 351 return (res); | |
| 352 } | |
| 353 | |
| 354 size_t | |
| 355 bufferevent_read(struct bufferevent *bufev, void *data, size_t size) | |
| 356 { | |
| 357 struct evbuffer *buf = bufev->input; | |
| 358 | |
| 359 if (buf->off < size) | |
| 360 size = buf->off; | |
| 361 | |
| 362 /* Copy the available data to the user buffer */ | |
| 363 memcpy(data, buf->buffer, size); | |
| 364 | |
| 365 if (size) | |
| 366 evbuffer_drain(buf, size); | |
| 367 | |
| 368 return (size); | |
| 369 } | |
| 370 | |
| 371 int | |
| 372 bufferevent_enable(struct bufferevent *bufev, short event) | |
| 373 { | |
| 374 if (event & EV_READ) { | |
| 375 if (bufferevent_add(&bufev->ev_read, bufev->timeout_read) == -1) | |
| 376 return (-1); | |
| 377 } | |
| 378 if (event & EV_WRITE) { | |
| 379 if (bufferevent_add(&bufev->ev_write, bufev->timeout_write) == -
1) | |
| 380 return (-1); | |
| 381 } | |
| 382 | |
| 383 bufev->enabled |= event; | |
| 384 return (0); | |
| 385 } | |
| 386 | |
| 387 int | |
| 388 bufferevent_disable(struct bufferevent *bufev, short event) | |
| 389 { | |
| 390 if (event & EV_READ) { | |
| 391 if (event_del(&bufev->ev_read) == -1) | |
| 392 return (-1); | |
| 393 } | |
| 394 if (event & EV_WRITE) { | |
| 395 if (event_del(&bufev->ev_write) == -1) | |
| 396 return (-1); | |
| 397 } | |
| 398 | |
| 399 bufev->enabled &= ~event; | |
| 400 return (0); | |
| 401 } | |
| 402 | |
| 403 /* | |
| 404 * Sets the read and write timeout for a buffered event. | |
| 405 */ | |
| 406 | |
| 407 void | |
| 408 bufferevent_settimeout(struct bufferevent *bufev, | |
| 409 int timeout_read, int timeout_write) { | |
| 410 bufev->timeout_read = timeout_read; | |
| 411 bufev->timeout_write = timeout_write; | |
| 412 | |
| 413 if (event_pending(&bufev->ev_read, EV_READ, NULL)) | |
| 414 bufferevent_add(&bufev->ev_read, timeout_read); | |
| 415 if (event_pending(&bufev->ev_write, EV_WRITE, NULL)) | |
| 416 bufferevent_add(&bufev->ev_write, timeout_write); | |
| 417 } | |
| 418 | |
| 419 /* | |
| 420 * Sets the water marks | |
| 421 */ | |
| 422 | |
| 423 void | |
| 424 bufferevent_setwatermark(struct bufferevent *bufev, short events, | |
| 425 size_t lowmark, size_t highmark) | |
| 426 { | |
| 427 if (events & EV_READ) { | |
| 428 bufev->wm_read.low = lowmark; | |
| 429 bufev->wm_read.high = highmark; | |
| 430 } | |
| 431 | |
| 432 if (events & EV_WRITE) { | |
| 433 bufev->wm_write.low = lowmark; | |
| 434 bufev->wm_write.high = highmark; | |
| 435 } | |
| 436 | |
| 437 /* If the watermarks changed then see if we should call read again */ | |
| 438 bufferevent_read_pressure_cb(bufev->input, | |
| 439 0, EVBUFFER_LENGTH(bufev->input), bufev); | |
| 440 } | |
| 441 | |
| 442 int | |
| 443 bufferevent_base_set(struct event_base *base, struct bufferevent *bufev) | |
| 444 { | |
| 445 int res; | |
| 446 | |
| 447 bufev->ev_base = base; | |
| 448 | |
| 449 res = event_base_set(base, &bufev->ev_read); | |
| 450 if (res == -1) | |
| 451 return (res); | |
| 452 | |
| 453 res = event_base_set(base, &bufev->ev_write); | |
| 454 return (res); | |
| 455 } | |
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Chromium Code Reviews
Issue 1531573008:
move libevent into base (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master