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/* Copyright (c) 2016, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file pubsub.c
*
* \brief DOCDOC
*/
#include "orconfig.h"
#include "pubsub.h"
#include "container.h"
/** Helper: insert <b>s</b> into <b>topic's</b> list of subscribers, keeping
* them sorted in priority order. */
static void
subscriber_insert(pubsub_topic_t *topic, pubsub_subscriber_t *s)
{
int i;
smartlist_t *sl = topic->subscribers;
for (i = 0; i < smartlist_len(sl); ++i) {
pubsub_subscriber_t *other = smartlist_get(sl, i);
if (s->priority < other->priority) {
break;
}
}
smartlist_insert(sl, i, s);
}
/**
* Add a new subscriber to <b>topic</b>, where (when an event is triggered),
* we'll notify the function <b>fn</b> by passing it <b>subscriber_data</b>.
* Return a handle to the subscribe which can later be passed to
* pubsub_unsubscribe_().
*
* Functions are called in priority order, from lowest to highest.
*
* See pubsub.h for <b>subscribe_flags</b>.
*/
const pubsub_subscriber_t *
pubsub_subscribe_(pubsub_topic_t *topic,
pubsub_subscriber_fn_t fn,
void *subscriber_data,
unsigned subscribe_flags,
unsigned priority)
{
tor_assert(! topic->locked);
if (subscribe_flags & SUBSCRIBE_ATSTART) {
tor_assert(topic->n_events_fired == 0);
}
pubsub_subscriber_t *r = tor_malloc_zero(sizeof(*r));
r->priority = priority;
r->subscriber_flags = subscribe_flags;
r->fn = fn;
r->subscriber_data = subscriber_data;
if (topic->subscribers == NULL) {
topic->subscribers = smartlist_new();
}
subscriber_insert(topic, r);
return r;
}
/**
* Remove the subscriber <b>s</b> from <b>topic</b>. After calling this
* function, <b>s</b> may no longer be used.
*/
int
pubsub_unsubscribe_(pubsub_topic_t *topic,
const pubsub_subscriber_t *s)
{
tor_assert(! topic->locked);
smartlist_t *sl = topic->subscribers;
if (sl == NULL)
return -1;
int i = smartlist_pos(sl, s);
if (i == -1)
return -1;
pubsub_subscriber_t *tmp = smartlist_get(sl, i);
tor_assert(tmp == s);
smartlist_del_keeporder(sl, i);
tor_free(tmp);
return 0;
}
/**
* For every subscriber s in <b>topic</b>, invoke notify_fn on s and
* event_data. Return 0 if there were no nonzero return values, and -1 if
* there were any.
*/
int
pubsub_notify_(pubsub_topic_t *topic, pubsub_notify_fn_t notify_fn,
void *event_data, unsigned notify_flags)
{
tor_assert(! topic->locked);
(void) notify_flags;
smartlist_t *sl = topic->subscribers;
int n_bad = 0;
++topic->n_events_fired;
if (sl == NULL)
return -1;
topic->locked = 1;
SMARTLIST_FOREACH_BEGIN(sl, pubsub_subscriber_t *, s) {
int r = notify_fn(s, event_data);
if (r != 0)
++n_bad;
} SMARTLIST_FOREACH_END(s);
topic->locked = 0;
return (n_bad == 0) ? 0 : -1;
}
/**
* Release all storage held by <b>topic</b>.
*/
void
pubsub_clear_(pubsub_topic_t *topic)
{
tor_assert(! topic->locked);
smartlist_t *sl = topic->subscribers;
if (sl == NULL)
return;
SMARTLIST_FOREACH_BEGIN(sl, pubsub_subscriber_t *, s) {
tor_free(s);
} SMARTLIST_FOREACH_END(s);
smartlist_free(sl);
topic->subscribers = NULL;
topic->n_events_fired = 0;
}
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