1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/ipc/chromium/src/third_party/libevent/bufferevent_pair.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,333 @@
1.4 +/*
1.5 + * Copyright (c) 2009-2012 Niels Provos, Nick Mathewson
1.6 + *
1.7 + * Redistribution and use in source and binary forms, with or without
1.8 + * modification, are permitted provided that the following conditions
1.9 + * are met:
1.10 + * 1. Redistributions of source code must retain the above copyright
1.11 + * notice, this list of conditions and the following disclaimer.
1.12 + * 2. Redistributions in binary form must reproduce the above copyright
1.13 + * notice, this list of conditions and the following disclaimer in the
1.14 + * documentation and/or other materials provided with the distribution.
1.15 + * 3. The name of the author may not be used to endorse or promote products
1.16 + * derived from this software without specific prior written permission.
1.17 + *
1.18 + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
1.19 + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1.20 + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
1.21 + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
1.22 + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
1.23 + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.24 + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.25 + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.26 + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1.27 + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.28 + */
1.29 +
1.30 +#include <sys/types.h>
1.31 +
1.32 +#ifdef WIN32
1.33 +#include <winsock2.h>
1.34 +#endif
1.35 +
1.36 +#include "event2/event-config.h"
1.37 +
1.38 +#include "event2/util.h"
1.39 +#include "event2/buffer.h"
1.40 +#include "event2/bufferevent.h"
1.41 +#include "event2/bufferevent_struct.h"
1.42 +#include "event2/event.h"
1.43 +#include "defer-internal.h"
1.44 +#include "bufferevent-internal.h"
1.45 +#include "mm-internal.h"
1.46 +#include "util-internal.h"
1.47 +
1.48 +struct bufferevent_pair {
1.49 + struct bufferevent_private bev;
1.50 + struct bufferevent_pair *partner;
1.51 +};
1.52 +
1.53 +
1.54 +/* Given a bufferevent that's really a bev part of a bufferevent_pair,
1.55 + * return that bufferevent_filtered. Returns NULL otherwise.*/
1.56 +static inline struct bufferevent_pair *
1.57 +upcast(struct bufferevent *bev)
1.58 +{
1.59 + struct bufferevent_pair *bev_p;
1.60 + if (bev->be_ops != &bufferevent_ops_pair)
1.61 + return NULL;
1.62 + bev_p = EVUTIL_UPCAST(bev, struct bufferevent_pair, bev.bev);
1.63 + EVUTIL_ASSERT(bev_p->bev.bev.be_ops == &bufferevent_ops_pair);
1.64 + return bev_p;
1.65 +}
1.66 +
1.67 +#define downcast(bev_pair) (&(bev_pair)->bev.bev)
1.68 +
1.69 +static inline void
1.70 +incref_and_lock(struct bufferevent *b)
1.71 +{
1.72 + struct bufferevent_pair *bevp;
1.73 + _bufferevent_incref_and_lock(b);
1.74 + bevp = upcast(b);
1.75 + if (bevp->partner)
1.76 + _bufferevent_incref_and_lock(downcast(bevp->partner));
1.77 +}
1.78 +
1.79 +static inline void
1.80 +decref_and_unlock(struct bufferevent *b)
1.81 +{
1.82 + struct bufferevent_pair *bevp = upcast(b);
1.83 + if (bevp->partner)
1.84 + _bufferevent_decref_and_unlock(downcast(bevp->partner));
1.85 + _bufferevent_decref_and_unlock(b);
1.86 +}
1.87 +
1.88 +/* XXX Handle close */
1.89 +
1.90 +static void be_pair_outbuf_cb(struct evbuffer *,
1.91 + const struct evbuffer_cb_info *, void *);
1.92 +
1.93 +static struct bufferevent_pair *
1.94 +bufferevent_pair_elt_new(struct event_base *base,
1.95 + int options)
1.96 +{
1.97 + struct bufferevent_pair *bufev;
1.98 + if (! (bufev = mm_calloc(1, sizeof(struct bufferevent_pair))))
1.99 + return NULL;
1.100 + if (bufferevent_init_common(&bufev->bev, base, &bufferevent_ops_pair,
1.101 + options)) {
1.102 + mm_free(bufev);
1.103 + return NULL;
1.104 + }
1.105 + if (!evbuffer_add_cb(bufev->bev.bev.output, be_pair_outbuf_cb, bufev)) {
1.106 + bufferevent_free(downcast(bufev));
1.107 + return NULL;
1.108 + }
1.109 +
1.110 + _bufferevent_init_generic_timeout_cbs(&bufev->bev.bev);
1.111 +
1.112 + return bufev;
1.113 +}
1.114 +
1.115 +int
1.116 +bufferevent_pair_new(struct event_base *base, int options,
1.117 + struct bufferevent *pair[2])
1.118 +{
1.119 + struct bufferevent_pair *bufev1 = NULL, *bufev2 = NULL;
1.120 + int tmp_options;
1.121 +
1.122 + options |= BEV_OPT_DEFER_CALLBACKS;
1.123 + tmp_options = options & ~BEV_OPT_THREADSAFE;
1.124 +
1.125 + bufev1 = bufferevent_pair_elt_new(base, options);
1.126 + if (!bufev1)
1.127 + return -1;
1.128 + bufev2 = bufferevent_pair_elt_new(base, tmp_options);
1.129 + if (!bufev2) {
1.130 + bufferevent_free(downcast(bufev1));
1.131 + return -1;
1.132 + }
1.133 +
1.134 + if (options & BEV_OPT_THREADSAFE) {
1.135 + /*XXXX check return */
1.136 + bufferevent_enable_locking(downcast(bufev2), bufev1->bev.lock);
1.137 + }
1.138 +
1.139 + bufev1->partner = bufev2;
1.140 + bufev2->partner = bufev1;
1.141 +
1.142 + evbuffer_freeze(downcast(bufev1)->input, 0);
1.143 + evbuffer_freeze(downcast(bufev1)->output, 1);
1.144 + evbuffer_freeze(downcast(bufev2)->input, 0);
1.145 + evbuffer_freeze(downcast(bufev2)->output, 1);
1.146 +
1.147 + pair[0] = downcast(bufev1);
1.148 + pair[1] = downcast(bufev2);
1.149 +
1.150 + return 0;
1.151 +}
1.152 +
1.153 +static void
1.154 +be_pair_transfer(struct bufferevent *src, struct bufferevent *dst,
1.155 + int ignore_wm)
1.156 +{
1.157 + size_t src_size, dst_size;
1.158 + size_t n;
1.159 +
1.160 + evbuffer_unfreeze(src->output, 1);
1.161 + evbuffer_unfreeze(dst->input, 0);
1.162 +
1.163 + if (dst->wm_read.high) {
1.164 + dst_size = evbuffer_get_length(dst->input);
1.165 + if (dst_size < dst->wm_read.high) {
1.166 + n = dst->wm_read.high - dst_size;
1.167 + evbuffer_remove_buffer(src->output, dst->input, n);
1.168 + } else {
1.169 + if (!ignore_wm)
1.170 + goto done;
1.171 + n = evbuffer_get_length(src->output);
1.172 + evbuffer_add_buffer(dst->input, src->output);
1.173 + }
1.174 + } else {
1.175 + n = evbuffer_get_length(src->output);
1.176 + evbuffer_add_buffer(dst->input, src->output);
1.177 + }
1.178 +
1.179 + if (n) {
1.180 + BEV_RESET_GENERIC_READ_TIMEOUT(dst);
1.181 +
1.182 + if (evbuffer_get_length(dst->output))
1.183 + BEV_RESET_GENERIC_WRITE_TIMEOUT(dst);
1.184 + else
1.185 + BEV_DEL_GENERIC_WRITE_TIMEOUT(dst);
1.186 + }
1.187 +
1.188 + src_size = evbuffer_get_length(src->output);
1.189 + dst_size = evbuffer_get_length(dst->input);
1.190 +
1.191 + if (dst_size >= dst->wm_read.low) {
1.192 + _bufferevent_run_readcb(dst);
1.193 + }
1.194 + if (src_size <= src->wm_write.low) {
1.195 + _bufferevent_run_writecb(src);
1.196 + }
1.197 +done:
1.198 + evbuffer_freeze(src->output, 1);
1.199 + evbuffer_freeze(dst->input, 0);
1.200 +}
1.201 +
1.202 +static inline int
1.203 +be_pair_wants_to_talk(struct bufferevent_pair *src,
1.204 + struct bufferevent_pair *dst)
1.205 +{
1.206 + return (downcast(src)->enabled & EV_WRITE) &&
1.207 + (downcast(dst)->enabled & EV_READ) &&
1.208 + !dst->bev.read_suspended &&
1.209 + evbuffer_get_length(downcast(src)->output);
1.210 +}
1.211 +
1.212 +static void
1.213 +be_pair_outbuf_cb(struct evbuffer *outbuf,
1.214 + const struct evbuffer_cb_info *info, void *arg)
1.215 +{
1.216 + struct bufferevent_pair *bev_pair = arg;
1.217 + struct bufferevent_pair *partner = bev_pair->partner;
1.218 +
1.219 + incref_and_lock(downcast(bev_pair));
1.220 +
1.221 + if (info->n_added > info->n_deleted && partner) {
1.222 + /* We got more data. If the other side's reading, then
1.223 + hand it over. */
1.224 + if (be_pair_wants_to_talk(bev_pair, partner)) {
1.225 + be_pair_transfer(downcast(bev_pair), downcast(partner), 0);
1.226 + }
1.227 + }
1.228 +
1.229 + decref_and_unlock(downcast(bev_pair));
1.230 +}
1.231 +
1.232 +static int
1.233 +be_pair_enable(struct bufferevent *bufev, short events)
1.234 +{
1.235 + struct bufferevent_pair *bev_p = upcast(bufev);
1.236 + struct bufferevent_pair *partner = bev_p->partner;
1.237 +
1.238 + incref_and_lock(bufev);
1.239 +
1.240 + if (events & EV_READ) {
1.241 + BEV_RESET_GENERIC_READ_TIMEOUT(bufev);
1.242 + }
1.243 + if ((events & EV_WRITE) && evbuffer_get_length(bufev->output))
1.244 + BEV_RESET_GENERIC_WRITE_TIMEOUT(bufev);
1.245 +
1.246 + /* We're starting to read! Does the other side have anything to write?*/
1.247 + if ((events & EV_READ) && partner &&
1.248 + be_pair_wants_to_talk(partner, bev_p)) {
1.249 + be_pair_transfer(downcast(partner), bufev, 0);
1.250 + }
1.251 + /* We're starting to write! Does the other side want to read? */
1.252 + if ((events & EV_WRITE) && partner &&
1.253 + be_pair_wants_to_talk(bev_p, partner)) {
1.254 + be_pair_transfer(bufev, downcast(partner), 0);
1.255 + }
1.256 + decref_and_unlock(bufev);
1.257 + return 0;
1.258 +}
1.259 +
1.260 +static int
1.261 +be_pair_disable(struct bufferevent *bev, short events)
1.262 +{
1.263 + if (events & EV_READ) {
1.264 + BEV_DEL_GENERIC_READ_TIMEOUT(bev);
1.265 + }
1.266 + if (events & EV_WRITE)
1.267 + BEV_DEL_GENERIC_WRITE_TIMEOUT(bev);
1.268 + return 0;
1.269 +}
1.270 +
1.271 +static void
1.272 +be_pair_destruct(struct bufferevent *bev)
1.273 +{
1.274 + struct bufferevent_pair *bev_p = upcast(bev);
1.275 +
1.276 + if (bev_p->partner) {
1.277 + bev_p->partner->partner = NULL;
1.278 + bev_p->partner = NULL;
1.279 + }
1.280 +
1.281 + _bufferevent_del_generic_timeout_cbs(bev);
1.282 +}
1.283 +
1.284 +static int
1.285 +be_pair_flush(struct bufferevent *bev, short iotype,
1.286 + enum bufferevent_flush_mode mode)
1.287 +{
1.288 + struct bufferevent_pair *bev_p = upcast(bev);
1.289 + struct bufferevent *partner;
1.290 + incref_and_lock(bev);
1.291 + if (!bev_p->partner)
1.292 + return -1;
1.293 +
1.294 + partner = downcast(bev_p->partner);
1.295 +
1.296 + if (mode == BEV_NORMAL)
1.297 + return 0;
1.298 +
1.299 + if ((iotype & EV_READ) != 0)
1.300 + be_pair_transfer(partner, bev, 1);
1.301 +
1.302 + if ((iotype & EV_WRITE) != 0)
1.303 + be_pair_transfer(bev, partner, 1);
1.304 +
1.305 + if (mode == BEV_FINISHED) {
1.306 + _bufferevent_run_eventcb(partner, iotype|BEV_EVENT_EOF);
1.307 + }
1.308 + decref_and_unlock(bev);
1.309 + return 0;
1.310 +}
1.311 +
1.312 +struct bufferevent *
1.313 +bufferevent_pair_get_partner(struct bufferevent *bev)
1.314 +{
1.315 + struct bufferevent_pair *bev_p;
1.316 + struct bufferevent *partner;
1.317 + bev_p = upcast(bev);
1.318 + if (! bev_p)
1.319 + return NULL;
1.320 +
1.321 + incref_and_lock(bev);
1.322 + partner = downcast(bev_p->partner);
1.323 + decref_and_unlock(bev);
1.324 + return partner;
1.325 +}
1.326 +
1.327 +const struct bufferevent_ops bufferevent_ops_pair = {
1.328 + "pair_elt",
1.329 + evutil_offsetof(struct bufferevent_pair, bev.bev),
1.330 + be_pair_enable,
1.331 + be_pair_disable,
1.332 + be_pair_destruct,
1.333 + _bufferevent_generic_adj_timeouts,
1.334 + be_pair_flush,
1.335 + NULL, /* ctrl */
1.336 +};
