479 lines
12 KiB
C
479 lines
12 KiB
C
/*
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* Asterisk -- An open source telephony toolkit.
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*
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* Copyright (C) 2013, Digium, Inc.
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*
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* David M. Lee, II <dlee@digium.com>
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*
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* See http://www.asterisk.org for more information about
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* the Asterisk project. Please do not directly contact
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* any of the maintainers of this project for assistance;
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* the project provides a web site, mailing lists and IRC
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* channels for your use.
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*
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* This program is free software, distributed under the terms of
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* the GNU General Public License Version 2. See the LICENSE file
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* at the top of the source tree.
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*/
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/*! \file
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*
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* \brief Stasis Message API.
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*
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* \author David M. Lee, II <dlee@digium.com>
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*/
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/*** MODULEINFO
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<support_level>core</support_level>
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***/
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#include "asterisk.h"
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ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
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#include "asterisk/astobj2.h"
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#include "asterisk/hashtab.h"
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#include "asterisk/stasis.h"
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#include "asterisk/utils.h"
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#ifdef LOW_MEMORY
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#define NUM_CACHE_BUCKETS 17
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#else
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#define NUM_CACHE_BUCKETS 563
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#endif
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/*! \internal */
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struct stasis_caching_topic {
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struct ao2_container *cache;
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struct stasis_topic *topic;
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struct stasis_subscription *sub;
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snapshot_get_id id_fn;
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};
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static void stasis_caching_topic_dtor(void *obj) {
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struct stasis_caching_topic *caching_topic = obj;
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ast_assert(!stasis_subscription_is_subscribed(caching_topic->sub));
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caching_topic->sub = NULL;
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ao2_cleanup(caching_topic->cache);
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caching_topic->cache = NULL;
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ao2_cleanup(caching_topic->topic);
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caching_topic->topic = NULL;
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}
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struct stasis_topic *stasis_caching_get_topic(struct stasis_caching_topic *caching_topic)
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{
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return caching_topic->topic;
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}
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struct stasis_caching_topic *stasis_caching_unsubscribe(struct stasis_caching_topic *caching_topic)
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{
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if (caching_topic) {
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if (stasis_subscription_is_subscribed(caching_topic->sub)) {
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stasis_unsubscribe(caching_topic->sub);
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} else {
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ast_log(LOG_ERROR, "stasis_caching_topic unsubscribed multiple times\n");
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}
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}
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return NULL;
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}
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struct cache_entry {
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struct stasis_message_type *type;
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char *id;
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struct stasis_message *snapshot;
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};
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static void cache_entry_dtor(void *obj)
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{
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struct cache_entry *entry = obj;
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ao2_cleanup(entry->type);
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entry->type = NULL;
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ast_free(entry->id);
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entry->id = NULL;
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ao2_cleanup(entry->snapshot);
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entry->snapshot = NULL;
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}
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static struct cache_entry *cache_entry_create(struct stasis_message_type *type, const char *id, struct stasis_message *snapshot)
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{
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RAII_VAR(struct cache_entry *, entry, NULL, ao2_cleanup);
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ast_assert(type != NULL);
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ast_assert(id != NULL);
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entry = ao2_alloc(sizeof(*entry), cache_entry_dtor);
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if (!entry) {
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return NULL;
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}
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entry->id = ast_strdup(id);
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if (!entry->id) {
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return NULL;
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}
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ao2_ref(type, +1);
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entry->type = type;
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if (snapshot != NULL) {
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ao2_ref(snapshot, +1);
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entry->snapshot = snapshot;
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}
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ao2_ref(entry, +1);
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return entry;
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}
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static int cache_entry_hash(const void *obj, int flags)
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{
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const struct cache_entry *entry = obj;
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int hash = 0;
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ast_assert(!(flags & OBJ_KEY));
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hash += ast_hashtab_hash_string(stasis_message_type_name(entry->type));
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hash += ast_hashtab_hash_string(entry->id);
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return hash;
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}
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static int cache_entry_cmp(void *obj, void *arg, int flags)
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{
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const struct cache_entry *left = obj;
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const struct cache_entry *right = arg;
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ast_assert(!(flags & OBJ_KEY));
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if (left->type == right->type && strcmp(left->id, right->id) == 0) {
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return CMP_MATCH | CMP_STOP;
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}
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return 0;
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}
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static struct stasis_message *cache_put(struct stasis_caching_topic *caching_topic, struct stasis_message_type *type, const char *id, struct stasis_message *new_snapshot)
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{
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RAII_VAR(struct cache_entry *, new_entry, NULL, ao2_cleanup);
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RAII_VAR(struct cache_entry *, cached_entry, NULL, ao2_cleanup);
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struct stasis_message *old_snapshot = NULL;
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ast_assert(caching_topic->cache != NULL);
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new_entry = cache_entry_create(type, id, new_snapshot);
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if (new_snapshot == NULL) {
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/* Remove entry from cache */
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cached_entry = ao2_find(caching_topic->cache, new_entry, OBJ_POINTER | OBJ_UNLINK);
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if (cached_entry) {
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old_snapshot = cached_entry->snapshot;
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cached_entry->snapshot = NULL;
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}
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} else {
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/* Insert/update cache */
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SCOPED_AO2LOCK(lock, caching_topic->cache);
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cached_entry = ao2_find(caching_topic->cache, new_entry, OBJ_POINTER | OBJ_NOLOCK);
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if (cached_entry) {
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/* Update cache. Because objects are moving, no need to update refcounts. */
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old_snapshot = cached_entry->snapshot;
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cached_entry->snapshot = new_entry->snapshot;
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new_entry->snapshot = NULL;
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} else {
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/* Insert into the cache */
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ao2_link_flags(caching_topic->cache, new_entry, OBJ_NOLOCK);
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}
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}
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return old_snapshot;
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}
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struct stasis_message *stasis_cache_get(struct stasis_caching_topic *caching_topic, struct stasis_message_type *type, const char *id)
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{
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RAII_VAR(struct cache_entry *, search_entry, NULL, ao2_cleanup);
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RAII_VAR(struct cache_entry *, cached_entry, NULL, ao2_cleanup);
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ast_assert(caching_topic->cache != NULL);
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search_entry = cache_entry_create(type, id, NULL);
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if (search_entry == NULL) {
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return NULL;
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}
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cached_entry = ao2_find(caching_topic->cache, search_entry, OBJ_POINTER);
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if (cached_entry == NULL) {
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return NULL;
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}
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ast_assert(cached_entry->snapshot != NULL);
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ao2_ref(cached_entry->snapshot, +1);
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return cached_entry->snapshot;
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}
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struct cache_dump_data {
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struct ao2_container *cached;
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struct stasis_message_type *type;
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};
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static int cache_dump_cb(void *obj, void *arg, int flags)
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{
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struct cache_dump_data *cache_dump = arg;
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struct cache_entry *entry = obj;
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if (!cache_dump->type || entry->type == cache_dump->type) {
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ao2_link(cache_dump->cached, entry->snapshot);
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}
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return 0;
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}
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struct ao2_container *stasis_cache_dump(struct stasis_caching_topic *caching_topic, struct stasis_message_type *type)
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{
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struct cache_dump_data cache_dump;
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ast_assert(caching_topic->cache != NULL);
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cache_dump.type = type;
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cache_dump.cached = ao2_container_alloc(1, NULL, NULL);
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if (!cache_dump.cached) {
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return NULL;
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}
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ao2_callback(caching_topic->cache, OBJ_MULTIPLE | OBJ_NODATA, cache_dump_cb, &cache_dump);
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return cache_dump.cached;
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}
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static struct stasis_message_type *__cache_clear_data;
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static struct stasis_message_type *cache_clear_data(void)
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{
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ast_assert(__cache_clear_data != NULL);
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return __cache_clear_data;
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}
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static struct stasis_message_type *__cache_update;
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struct stasis_message_type *stasis_cache_update_type(void)
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{
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ast_assert(__cache_update != NULL);
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return __cache_update;
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}
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struct cache_clear_data {
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struct stasis_message_type *type;
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char *id;
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};
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static void cache_clear_data_dtor(void *obj)
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{
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struct cache_clear_data *ev = obj;
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ast_free(ev->id);
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ev->id = NULL;
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ao2_cleanup(ev->type);
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ev->type = NULL;
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}
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struct stasis_message *stasis_cache_clear_create(struct stasis_message_type *type, const char *id)
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{
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RAII_VAR(struct cache_clear_data *, ev, NULL, ao2_cleanup);
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RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
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ev = ao2_alloc(sizeof(*ev), cache_clear_data_dtor);
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if (!ev) {
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return NULL;
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}
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ev->id = ast_strdup(id);
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if (!ev->id) {
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return NULL;
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}
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ao2_ref(type, +1);
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ev->type = type;
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msg = stasis_message_create(cache_clear_data(), ev);
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if (!msg) {
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return NULL;
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}
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ao2_ref(msg, +1);
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return msg;
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}
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static void stasis_cache_update_dtor(void *obj)
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{
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struct stasis_cache_update *update = obj;
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ao2_cleanup(update->topic);
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update->topic = NULL;
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ao2_cleanup(update->old_snapshot);
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update->old_snapshot = NULL;
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ao2_cleanup(update->new_snapshot);
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update->new_snapshot = NULL;
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ao2_cleanup(update->type);
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update->type = NULL;
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}
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static struct stasis_message *update_create(struct stasis_topic *topic, struct stasis_message *old_snapshot, struct stasis_message *new_snapshot)
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{
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RAII_VAR(struct stasis_cache_update *, update, NULL, ao2_cleanup);
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RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
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ast_assert(topic != NULL);
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ast_assert(old_snapshot != NULL || new_snapshot != NULL);
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update = ao2_alloc(sizeof(*update), stasis_cache_update_dtor);
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if (!update) {
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return NULL;
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}
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ao2_ref(topic, +1);
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update->topic = topic;
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if (old_snapshot) {
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ao2_ref(old_snapshot, +1);
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update->old_snapshot = old_snapshot;
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if (!new_snapshot) {
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ao2_ref(stasis_message_type(old_snapshot), +1);
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update->type = stasis_message_type(old_snapshot);
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}
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}
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if (new_snapshot) {
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ao2_ref(new_snapshot, +1);
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update->new_snapshot = new_snapshot;
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ao2_ref(stasis_message_type(new_snapshot), +1);
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update->type = stasis_message_type(new_snapshot);
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}
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msg = stasis_message_create(stasis_cache_update_type(), update);
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if (!msg) {
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return NULL;
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}
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ao2_ref(msg, +1);
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return msg;
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}
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static void caching_topic_exec(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *message)
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{
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RAII_VAR(struct stasis_caching_topic *, caching_topic_needs_unref, NULL, ao2_cleanup);
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struct stasis_caching_topic *caching_topic = data;
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const char *id = NULL;
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ast_assert(caching_topic->topic != NULL);
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ast_assert(caching_topic->id_fn != NULL);
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if (stasis_subscription_final_message(sub, message)) {
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caching_topic_needs_unref = caching_topic;
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}
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/* Handle cache clear event */
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if (cache_clear_data() == stasis_message_type(message)) {
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RAII_VAR(struct stasis_message *, old_snapshot, NULL, ao2_cleanup);
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RAII_VAR(struct stasis_message *, update, NULL, ao2_cleanup);
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struct cache_clear_data *clear = stasis_message_data(message);
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ast_assert(clear->type != NULL);
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ast_assert(clear->id != NULL);
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old_snapshot = cache_put(caching_topic, clear->type, clear->id, NULL);
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if (old_snapshot) {
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update = update_create(topic, old_snapshot, NULL);
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stasis_publish(caching_topic->topic, update);
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} else {
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ast_log(LOG_ERROR,
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"Attempting to remove an item from the cache that isn't there: %s %s\n",
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stasis_message_type_name(clear->type), clear->id);
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}
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return;
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}
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id = caching_topic->id_fn(message);
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if (id == NULL) {
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/* Object isn't cached; forward */
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stasis_forward_message(caching_topic->topic, topic, message);
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} else {
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/* Update the cache */
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RAII_VAR(struct stasis_message *, old_snapshot, NULL, ao2_cleanup);
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RAII_VAR(struct stasis_message *, update, NULL, ao2_cleanup);
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old_snapshot = cache_put(caching_topic, stasis_message_type(message), id, message);
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update = update_create(topic, old_snapshot, message);
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if (update == NULL) {
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return;
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}
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stasis_publish(caching_topic->topic, update);
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}
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if (stasis_subscription_final_message(sub, message)) {
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ao2_cleanup(caching_topic);
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}
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}
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struct stasis_caching_topic *stasis_caching_topic_create(struct stasis_topic *original_topic, snapshot_get_id id_fn)
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{
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RAII_VAR(struct stasis_caching_topic *, caching_topic, NULL, ao2_cleanup);
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struct stasis_subscription *sub;
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RAII_VAR(char *, new_name, NULL, free);
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int ret;
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ret = asprintf(&new_name, "%s-cached", stasis_topic_name(original_topic));
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if (ret < 0) {
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return NULL;
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}
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caching_topic = ao2_alloc(sizeof(*caching_topic), stasis_caching_topic_dtor);
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if (caching_topic == NULL) {
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return NULL;
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}
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caching_topic->cache = ao2_container_alloc(NUM_CACHE_BUCKETS, cache_entry_hash, cache_entry_cmp);
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if (!caching_topic->cache) {
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ast_log(LOG_ERROR, "Stasis cache allocation failed\n");
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return NULL;
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}
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caching_topic->topic = stasis_topic_create(new_name);
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if (caching_topic->topic == NULL) {
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return NULL;
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}
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caching_topic->id_fn = id_fn;
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sub = stasis_subscribe(original_topic, caching_topic_exec, caching_topic);
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if (sub == NULL) {
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return NULL;
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}
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/* This is for the reference contained in the subscription above */
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ao2_ref(caching_topic, +1);
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caching_topic->sub = sub;
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ao2_ref(caching_topic, +1);
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return caching_topic;
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}
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static void stasis_cache_exit(void)
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{
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ao2_cleanup(__cache_clear_data);
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__cache_clear_data = NULL;
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ao2_cleanup(__cache_update);
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__cache_update = NULL;
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}
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int stasis_cache_init(void)
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{
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ast_register_atexit(stasis_cache_exit);
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if (__cache_clear_data || __cache_update) {
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ast_log(LOG_ERROR, "Stasis cache double initialized\n");
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return -1;
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}
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__cache_update = stasis_message_type_create("stasis_cache_update");
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if (!__cache_update) {
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return -1;
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}
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__cache_clear_data = stasis_message_type_create("StasisCacheClear");
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if (!__cache_clear_data) {
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return -1;
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}
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return 0;
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}
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