diff options
Diffstat (limited to 'protocols/Telegram/libevent/bufferevent_pair.c')
| -rw-r--r-- | protocols/Telegram/libevent/bufferevent_pair.c | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/protocols/Telegram/libevent/bufferevent_pair.c b/protocols/Telegram/libevent/bufferevent_pair.c new file mode 100644 index 0000000000..d80e5f81d6 --- /dev/null +++ b/protocols/Telegram/libevent/bufferevent_pair.c @@ -0,0 +1,360 @@ +/* + * 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 "event2/event-config.h" +#include "evconfig-private.h" + +#include <sys/types.h> + +#ifdef _WIN32 +#include <winsock2.h> +#endif + +#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; + /* For ->destruct() lock checking */ + struct bufferevent_pair *unlinked_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 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); + } + + bufferevent_trigger_nolock_(dst, EV_READ, 0); + bufferevent_trigger_nolock_(src, EV_WRITE, 0); +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_unlink(struct bufferevent *bev) +{ + struct bufferevent_pair *bev_p = upcast(bev); + + if (bev_p->partner) { + bev_p->unlinked_partner = bev_p->partner; + bev_p->partner->partner = NULL; + bev_p->partner = NULL; + } +} + +/* Free *shared* lock in the latest be (since we share it between two of them). */ +static void +be_pair_destruct(struct bufferevent *bev) +{ + struct bufferevent_pair *bev_p = upcast(bev); + + /* Transfer ownership of the lock into partner, otherwise we will use + * already free'd lock during freeing second bev, see next example: + * + * bev1->own_lock = 1 + * bev2->own_lock = 0 + * bev2->lock = bev1->lock + * + * bufferevent_free(bev1) # refcnt == 0 -> unlink + * bufferevent_free(bev2) # refcnt == 0 -> unlink + * + * event_base_free() -> finilizers -> EVTHREAD_FREE_LOCK(bev1->lock) + * -> BEV_LOCK(bev2->lock) <-- already freed + * + * Where bev1 == pair[0], bev2 == pair[1]. + */ + if (bev_p->unlinked_partner && bev_p->bev.own_lock) { + bev_p->unlinked_partner->bev.own_lock = 1; + bev_p->bev.own_lock = 0; + } + bev_p->unlinked_partner = NULL; +} + +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; + + if (!bev_p->partner) + return -1; + + if (mode == BEV_NORMAL) + return 0; + + incref_and_lock(bev); + + partner = downcast(bev_p->partner); + + 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, 0); + } + decref_and_unlock(bev); + return 0; +} + +struct bufferevent * +bufferevent_pair_get_partner(struct bufferevent *bev) +{ + struct bufferevent_pair *bev_p; + struct bufferevent *partner = NULL; + bev_p = upcast(bev); + if (! bev_p) + return NULL; + + incref_and_lock(bev); + if (bev_p->partner) + 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_unlink, + be_pair_destruct, + bufferevent_generic_adj_timeouts_, + be_pair_flush, + NULL, /* ctrl */ +}; |