The Tor Browser: ipc/chromium/src/third_party/libevent/bufferevent

ipc/chromium/src/third_party/libevent/bufferevent_pair.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/bufferevent_pair.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
  * Copyright (c) 2009-2012 Niels Provos, Nick Mathewson
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. The name of the author may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/types.h>
 #ifdef WIN32
 #include <winsock2.h>
 #endif
 #include "event2/event-config.h"
 #include "event2/util.h"
 #include "event2/buffer.h"
 #include "event2/bufferevent.h"
 #include "event2/bufferevent_struct.h"
 #include "event2/event.h"
 #include "defer-internal.h"
 #include "bufferevent-internal.h"
 #include "mm-internal.h"
 #include "util-internal.h"
 struct bufferevent_pair {
 	struct bufferevent_private bev;
 	struct bufferevent_pair *partner;
 };
 /* Given a bufferevent that's really a bev part of a bufferevent_pair,
  * return that bufferevent_filtered. Returns NULL otherwise.*/
 static inline struct bufferevent_pair *
 upcast(struct bufferevent *bev)
 {
 	struct bufferevent_pair *bev_p;
 	if (bev->be_ops != &bufferevent_ops_pair)
 		return NULL;
 	bev_p = EVUTIL_UPCAST(bev, struct bufferevent_pair, bev.bev);
 	EVUTIL_ASSERT(bev_p->bev.bev.be_ops == &bufferevent_ops_pair);
 	return bev_p;
 }
 #define downcast(bev_pair) (&(bev_pair)->bev.bev)
 static inline void
 incref_and_lock(struct bufferevent *b)
 {
 	struct bufferevent_pair *bevp;
 	_bufferevent_incref_and_lock(b);
 	bevp = upcast(b);
 	if (bevp->partner)
 		_bufferevent_incref_and_lock(downcast(bevp->partner));
 }
 static inline void
 decref_and_unlock(struct bufferevent *b)
 {
 	struct bufferevent_pair *bevp = upcast(b);
 	if (bevp->partner)
 		_bufferevent_decref_and_unlock(downcast(bevp->partner));
 	_bufferevent_decref_and_unlock(b);
 }
 /* XXX Handle close */
 static void be_pair_outbuf_cb(struct evbuffer *,
     const struct evbuffer_cb_info *, void *);
 static struct bufferevent_pair *
 bufferevent_pair_elt_new(struct event_base *base,
     int options)
 {
 	struct bufferevent_pair *bufev;
 	if (! (bufev = mm_calloc(1, sizeof(struct bufferevent_pair))))
 		return NULL;
 	if (bufferevent_init_common(&bufev->bev, base, &bufferevent_ops_pair,
 		options)) {
 		mm_free(bufev);
 		return NULL;
 	}
 	if (!evbuffer_add_cb(bufev->bev.bev.output, be_pair_outbuf_cb, bufev)) {
 		bufferevent_free(downcast(bufev));
 		return NULL;
 	}
 	_bufferevent_init_generic_timeout_cbs(&bufev->bev.bev);
 	return bufev;
 }
 int
 bufferevent_pair_new(struct event_base *base, int options,
     struct bufferevent *pair[2])
 {
 	struct bufferevent_pair *bufev1 = NULL, *bufev2 = NULL;
 	int tmp_options;
 	options |= BEV_OPT_DEFER_CALLBACKS;
 	tmp_options = options & ~BEV_OPT_THREADSAFE;
 	bufev1 = bufferevent_pair_elt_new(base, options);
 	if (!bufev1)
 		return -1;
 	bufev2 = bufferevent_pair_elt_new(base, tmp_options);
 	if (!bufev2) {
 		bufferevent_free(downcast(bufev1));
 		return -1;
 	}
 	if (options & BEV_OPT_THREADSAFE) {
 		/*XXXX check return */
 		bufferevent_enable_locking(downcast(bufev2), bufev1->bev.lock);
 	}
 	bufev1->partner = bufev2;
 	bufev2->partner = bufev1;
 	evbuffer_freeze(downcast(bufev1)->input, 0);
 	evbuffer_freeze(downcast(bufev1)->output, 1);
 	evbuffer_freeze(downcast(bufev2)->input, 0);
 	evbuffer_freeze(downcast(bufev2)->output, 1);
 	pair[0] = downcast(bufev1);
 	pair[1] = downcast(bufev2);
 	return 0;
 }
 static void
 be_pair_transfer(struct bufferevent *src, struct bufferevent *dst,
     int ignore_wm)
 {
 	size_t src_size, dst_size;
 	size_t n;
 	evbuffer_unfreeze(src->output, 1);
 	evbuffer_unfreeze(dst->input, 0);
 	if (dst->wm_read.high) {
 		dst_size = evbuffer_get_length(dst->input);
 		if (dst_size < dst->wm_read.high) {
 			n = dst->wm_read.high - dst_size;
 			evbuffer_remove_buffer(src->output, dst->input, n);
 		} else {
 			if (!ignore_wm)
 				goto done;
 			n = evbuffer_get_length(src->output);
 			evbuffer_add_buffer(dst->input, src->output);
 		}
 	} else {
 		n = evbuffer_get_length(src->output);
 		evbuffer_add_buffer(dst->input, src->output);
 	}
 	if (n) {
 		BEV_RESET_GENERIC_READ_TIMEOUT(dst);
 		if (evbuffer_get_length(dst->output))
 			BEV_RESET_GENERIC_WRITE_TIMEOUT(dst);
 		else
 			BEV_DEL_GENERIC_WRITE_TIMEOUT(dst);
 	}
 	src_size = evbuffer_get_length(src->output);
 	dst_size = evbuffer_get_length(dst->input);
 	if (dst_size >= dst->wm_read.low) {
 		_bufferevent_run_readcb(dst);
 	}
 	if (src_size <= src->wm_write.low) {
 		_bufferevent_run_writecb(src);
 	}
 done:
 	evbuffer_freeze(src->output, 1);
 	evbuffer_freeze(dst->input, 0);
 }
 static inline int
 be_pair_wants_to_talk(struct bufferevent_pair *src,
     struct bufferevent_pair *dst)
 {
 	return (downcast(src)->enabled & EV_WRITE) &&
 	    (downcast(dst)->enabled & EV_READ) &&
 	    !dst->bev.read_suspended &&
 	    evbuffer_get_length(downcast(src)->output);
 }
 static void
 be_pair_outbuf_cb(struct evbuffer *outbuf,
     const struct evbuffer_cb_info *info, void *arg)
 {
 	struct bufferevent_pair *bev_pair = arg;
 	struct bufferevent_pair *partner = bev_pair->partner;
 	incref_and_lock(downcast(bev_pair));
 	if (info->n_added > info->n_deleted && partner) {
 		/* We got more data.  If the other side's reading, then
 		   hand it over. */
 		if (be_pair_wants_to_talk(bev_pair, partner)) {
 			be_pair_transfer(downcast(bev_pair), downcast(partner), 0);
 		}
 	}
 	decref_and_unlock(downcast(bev_pair));
 }
 static int
 be_pair_enable(struct bufferevent *bufev, short events)
 {
 	struct bufferevent_pair *bev_p = upcast(bufev);
 	struct bufferevent_pair *partner = bev_p->partner;
 	incref_and_lock(bufev);
 	if (events & EV_READ) {
 		BEV_RESET_GENERIC_READ_TIMEOUT(bufev);
 	}
 	if ((events & EV_WRITE) && evbuffer_get_length(bufev->output))
 		BEV_RESET_GENERIC_WRITE_TIMEOUT(bufev);
 	/* We're starting to read! Does the other side have anything to write?*/
 	if ((events & EV_READ) && partner &&
 	    be_pair_wants_to_talk(partner, bev_p)) {
 		be_pair_transfer(downcast(partner), bufev, 0);
 	}
 	/* We're starting to write! Does the other side want to read? */
 	if ((events & EV_WRITE) && partner &&
 	    be_pair_wants_to_talk(bev_p, partner)) {
 		be_pair_transfer(bufev, downcast(partner), 0);
 	}
 	decref_and_unlock(bufev);
 	return 0;
 }
 static int
 be_pair_disable(struct bufferevent *bev, short events)
 {
 	if (events & EV_READ) {
 		BEV_DEL_GENERIC_READ_TIMEOUT(bev);
 	}
 	if (events & EV_WRITE)
 		BEV_DEL_GENERIC_WRITE_TIMEOUT(bev);
 	return 0;
 }
 static void
 be_pair_destruct(struct bufferevent *bev)
 {
 	struct bufferevent_pair *bev_p = upcast(bev);
 	if (bev_p->partner) {
 		bev_p->partner->partner = NULL;
 		bev_p->partner = NULL;
 	}
 	_bufferevent_del_generic_timeout_cbs(bev);
 }
 static int
 be_pair_flush(struct bufferevent *bev, short iotype,
     enum bufferevent_flush_mode mode)
 {
 	struct bufferevent_pair *bev_p = upcast(bev);
 	struct bufferevent *partner;
 	incref_and_lock(bev);
 	if (!bev_p->partner)
 		return -1;
 	partner = downcast(bev_p->partner);
 	if (mode == BEV_NORMAL)
 		return 0;
 	if ((iotype & EV_READ) != 0)
 		be_pair_transfer(partner, bev, 1);
 	if ((iotype & EV_WRITE) != 0)
 		be_pair_transfer(bev, partner, 1);
 	if (mode == BEV_FINISHED) {
 		_bufferevent_run_eventcb(partner, iotype|BEV_EVENT_EOF);
 	}
 	decref_and_unlock(bev);
 	return 0;
 }
 struct bufferevent *
 bufferevent_pair_get_partner(struct bufferevent *bev)
 {
 	struct bufferevent_pair *bev_p;
 	struct bufferevent *partner;
 	bev_p = upcast(bev);
 	if (! bev_p)
 		return NULL;
 	incref_and_lock(bev);
 	partner = downcast(bev_p->partner);
 	decref_and_unlock(bev);
 	return partner;
 }
 const struct bufferevent_ops bufferevent_ops_pair = {
 	"pair_elt",
 	evutil_offsetof(struct bufferevent_pair, bev.bev),
 	be_pair_enable,
 	be_pair_disable,
 	be_pair_destruct,
 	_bufferevent_generic_adj_timeouts,
 	be_pair_flush,
 	NULL, /* ctrl */
 };

The Tor Browser / annotate

ipc/chromium/src/third_party/libevent/bufferevent_pair.c@6474c204b198 (annotated)

ipc/chromium/src/third_party/libevent/bufferevent_pair.c