208 lines
6.3 KiB
C
208 lines
6.3 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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#ifndef _ASTERISK_STASIS_CACHE_PATTERN_H
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#define _ASTERISK_STASIS_CACHE_PATTERN_H
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/*! \file
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*
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* \brief Caching pattern for \ref stasis topics.
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*
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* A typical pattern for Stasis objects is to have individual objects, which
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* have their own topic and caching topic. These individual topics feed an
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* upstream aggregate topics, and a shared cache.
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*
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* The \ref stasis_cp_all object contains the aggregate topics and shared cache.
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* This is built with the base name for the topics, and the identity function to
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* identify messages in the cache.
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*
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* The \ref stasis_cp_single object contains the \ref stasis_topic for a single
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* instance, and the corresponding \ref stasis_caching_topic.
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*
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* Since the \ref stasis_cp_single object has subscriptions for forwarding
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* and caching, it must be disposed of using stasis_cp_single_unsubscribe()
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* instead of simply ao2_cleanup().
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*/
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#include "asterisk/stasis.h"
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/*!
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* \brief The 'all' side of the cache pattern. These are typically built as
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* global objects for specific modules.
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*/
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struct stasis_cp_all;
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/*!
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* \brief Create an all instance of the cache pattern.
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*
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* This object is AO2 managed, so dispose of it with ao2_cleanup().
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*
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* \param name Base name of the topics.
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* \param id_fn Identity function for the cache.
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* \return All side instance.
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* \retval NULL on error.
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*/
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struct stasis_cp_all *stasis_cp_all_create(const char *name,
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snapshot_get_id id_fn);
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/*!
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* \brief Get the aggregate topic.
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*
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* This topic aggregates all messages published to corresponding
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* stasis_cp_single_topic() topics.
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*
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* \param all All side caching pattern object.
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* \return The aggregate topic.
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* \retval NULL if \a all is \c NULL
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*/
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struct stasis_topic *stasis_cp_all_topic(struct stasis_cp_all *all);
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/*!
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* \brief Get the caching topic.
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*
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* This topic aggregates all messages from the corresponding
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* stasis_cp_single_topic_cached() topics.
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*
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* Note that one normally only subscribes to the caching topic, since data
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* is fed to it from its upstream topic.
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*
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* \param all All side caching pattern object.
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* \return The aggregate caching topic.
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* \retval NULL if \a all is \c NULL
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*/
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struct stasis_topic *stasis_cp_all_topic_cached(
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struct stasis_cp_all *all);
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/*!
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* \brief Get the cache.
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*
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* This is the shared cache for all corresponding \ref stasis_cp_single objects.
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*
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* \param all All side caching pattern object.
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* \return The cache.
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* \retval NULL if \a all is \c NULL
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*/
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struct stasis_cache *stasis_cp_all_cache(struct stasis_cp_all *all);
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/*!
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* \brief The 'one' side of the cache pattern. These are built per-instance for
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* some corresponding object, and must be explicitly disposed of using
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* stasis_cp_single_unsubscribe().
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*/
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struct stasis_cp_single;
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/*!
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* \brief Create the 'one' side of the cache pattern.
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*
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* Create the 'one' and forward to all's topic and topic_cached.
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*
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* Dispose of using stasis_cp_single_unsubscribe().
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*
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* \param all Corresponding all side.
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* \param name Base name for the topics.
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* \return One side instance
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*/
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struct stasis_cp_single *stasis_cp_single_create(struct stasis_cp_all *all,
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const char *name);
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/*!
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* \brief Create a sink in the cache pattern
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*
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* Create the 'one' but do not automatically forward to the all's topic.
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* This is useful when aggregating other topic's messages created with
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* \c stasis_cp_single_create in another caching topic without replicating
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* those messages in the all's topics.
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*
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* Dispose of using stasis_cp_single_unsubscribe().
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*
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* \param all Corresponding all side.
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* \param name Base name for the topics.
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* \return One side instance
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*/
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struct stasis_cp_single *stasis_cp_sink_create(struct stasis_cp_all *all,
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const char *name);
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/*!
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* \brief Stops caching and forwarding messages.
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*
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* \param one One side of the cache pattern.
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*/
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void stasis_cp_single_unsubscribe(struct stasis_cp_single *one);
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/*!
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* \brief Get the topic for this instance.
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*
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* This is the topic to which one would post instance-specific messages, or
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* subscribe for single-instance, uncached messages.
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*
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* \param one One side of the cache pattern.
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* \return The main topic.
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* \retval NULL if \a one is \c NULL
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*/
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struct stasis_topic *stasis_cp_single_topic(struct stasis_cp_single *one);
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/*!
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* \brief Get the caching topic for this instance.
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*
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* Note that one normally only subscribes to the caching topic, since data
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* is fed to it from its upstream topic.
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*
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* \param one One side of the cache pattern.
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* \return The caching topic.
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* \retval NULL if \a one is \c NULL
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*/
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struct stasis_topic *stasis_cp_single_topic_cached(
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struct stasis_cp_single *one);
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/*!
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* \brief Indicate to an instance that we are interested in a message type.
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*
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* This will cause the caching topic to receive messages of the given message
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* type. This enables internal filtering in the stasis message bus to reduce
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* messages.
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*
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* \param one One side of the cache pattern.
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* \param type The message type we wish to receive.
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* \retval 0 on success
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* \retval -1 failure
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*
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* \since 17.0.0
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*/
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int stasis_cp_single_accept_message_type(struct stasis_cp_single *one,
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struct stasis_message_type *type);
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/*!
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* \brief Set the message type filtering level on a cache
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*
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* This will cause the underlying subscription to filter messages according to the
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* provided filter level. For example if selective is used then only
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* messages matching those provided to \ref stasis_subscription_accept_message_type
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* will be raised to the subscription callback.
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*
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* \param one One side of the cache pattern.
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* \param filter What filter to use
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* \retval 0 on success
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* \retval -1 failure
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*
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* \since 17.0.0
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*/
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int stasis_cp_single_set_filter(struct stasis_cp_single *one,
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enum stasis_subscription_message_filter filter);
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#endif /* _ASTERISK_STASIS_CACHE_PATTERN_H */
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