Files
asterisk/include/asterisk/presencestate.h
David M. Lee e1b959ccbb Split caching out from the stasis_caching_topic.
In working with res_stasis, I discovered a significant limitation to
the current structure of stasis_caching_topics: you cannot subscribe
to cache updates for a single channel/bridge/endpoint/etc.

To address this, this patch splits the cache away from the
stasis_caching_topic, making it a first class object. The stasis_cache
object is shared amongst individual stasis_caching_topics that are
created per channel/endpoint/etc. These are still forwarded to global
whatever_all_cached topics, so their use from most of the code does
not change.

In making these changes, I noticed that we frequently used a similar
pattern for bridges, endpoints and channels:

     single_topic  ---------------->  all_topic
           ^
           |
     single_topic_cached  ----+---->  all_topic_cached
                              |
                              +---->  cache

This pattern was extracted as the 'Stasis Caching Pattern', defined in
stasis_caching_pattern.h. This avoids a lot of duplicate code between
the different domain objects.

Since the cache is now disassociated from its upstream caching topics,
this also necessitated a change to how the 'guaranteed' flag worked
for retrieving from a cache. The code for handling the caching
guarantee was extracted into a 'stasis_topic_wait' function, which
works for any stasis_topic.

(closes issue ASTERISK-22002)
Review: https://reviewboard.asterisk.org/r/2672/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@395954 65c4cc65-6c06-0410-ace0-fbb531ad65f3
2013-08-01 13:49:34 +00:00

196 lines
5.9 KiB
C

/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2011, Digium, Inc.
*
* David Vossel <dvossel@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*! \file
* \brief Presence state management
*/
#ifndef _ASTERISK_PRESSTATE_H
#define _ASTERISK_PRESSTATE_H
enum ast_presence_state {
AST_PRESENCE_NOT_SET = 0,
AST_PRESENCE_UNAVAILABLE,
AST_PRESENCE_AVAILABLE,
AST_PRESENCE_AWAY,
AST_PRESENCE_XA,
AST_PRESENCE_CHAT,
AST_PRESENCE_DND,
/* This is not something that a user can
* set his presence to. Rather, this is returned
* to indicate that presence is in some invalid
* state
*/
AST_PRESENCE_INVALID,
};
/*! \brief Presence state provider call back */
typedef enum ast_presence_state (*ast_presence_state_prov_cb_type)(const char *data, char **subtype, char **message);
/*!
* \brief Convert presence state to text string for output
*
* \param state Current presence state
*/
const char *ast_presence_state2str(enum ast_presence_state state);
/*!
* \brief Convert presence state from text to integer value
*
* \param val The text representing the presence state. Valid values are anything
* that comes after AST_PRESENCE_ in one of the defined values.
*
* \return The AST_PRESENCE_ integer value
*/
enum ast_presence_state ast_presence_state_val(const char *val);
/*!
* \brief Asks a presence state provider for the current presence state.
*
* \param presence_provider The presence provider to retrieve the state from.
* \param subtype The output paramenter to store the subtype string in. Must be freed if returned
* \param message The output paramenter to store the message string in. Must be freed if returned
*
* \retval presence state value on success,
* \retval -1 on failure.
*/
enum ast_presence_state ast_presence_state(const char *presence_provider, char **subtype, char **message);
/*!
* \brief Asks a presence state provider for the current presence state, bypassing the event cache
*
* \details Some presence state providers may perform transformations on presence data when it is
* requested (such as a base64 decode). In such instances, use of the event cache is not suitable
* and should be bypassed.
*
* \param presence_provider The presence provider to retrieve the state from.
* \param subtype The output paramenter to store the subtype string in. Must be freed if returned
* \param message The output paramenter to store the message string in. Must be freed if returned
*
* \retval presence state value on success,
* \retval -1 on failure.
*/
enum ast_presence_state ast_presence_state_nocache(const char *presence_provider, char **subtype, char **message);
/*!
* \brief Notify the world that a presence provider state changed.
*
* \param state the new presence state
* \param subtype the new presence subtype
* \param message the new presence message
* \param fmt Presence entity whose state has changed
*
* The new state of the entity will be sent off to any subscribers
* of the presence state. It will also be stored in the internal event
* cache.
*
* \retval 0 Success
* \retval -1 Failure
*/
int ast_presence_state_changed(enum ast_presence_state state,
const char *subtype,
const char *message,
const char *fmt, ...)
__attribute__((format(printf, 4, 5)));
/*!
* \brief Notify the world that a presence provider state changed.
*
* \param state the new presence state
* \param subtype the new presence subtype
* \param message the new presence message
* \param presence_provider Presence entity whose state has changed
*
* The new state of the entity will be sent off to any subscribers
* of the presence state. It will also be stored in the internal event
* cache.
*
* \retval 0 Success
* \retval -1 Failure
*/
int ast_presence_state_changed_literal(enum ast_presence_state state,
const char *subtype,
const char *message,
const char *presence_provider);
/*!
* \brief Add presence state provider
*
* \param label to use in hint, like label:object
* \param callback Callback
*
* \retval 0 success
* \retval -1 failure
*/
int ast_presence_state_prov_add(const char *label, ast_presence_state_prov_cb_type callback);
/*!
* \brief Remove presence state provider
*
* \param label to use in hint, like label:object
*
* \retval -1 on failure
* \retval 0 on success
*/
int ast_presence_state_prov_del(const char *label);
/*!
* \brief Get presence state message type
* \retval Stasis message type for presence state messages
* \since 12
*/
struct stasis_message_type *ast_presence_state_message_type(void);
/*!
* \brief Get presence state topic
* \retval Stasis topic for presence state messages
* \since 12
*/
struct stasis_topic *ast_presence_state_topic_all(void);
/*!
* \brief Get caching presence state topic
* \retval Caching Stasis topic for presence state messages
* \since 12
*/
struct stasis_topic *ast_presence_state_topic_cached(void);
/*!
* \brief Backend cache for ast_presence_state_topic_cached()
* \retval Cache of \ref ast_presence_state_message.
* \since 12
*/
struct stasis_cache *ast_presence_state_cache(void);
/*!
* \brief Stasis message payload representing a presence state update
* \since 12
*/
struct ast_presence_state_message {
AST_DECLARE_STRING_FIELDS(
AST_STRING_FIELD(provider); /*!< Provider that produced this presence state message */
AST_STRING_FIELD(subtype); /*!< Subtype associated with this presence state message */
AST_STRING_FIELD(message); /*!< The message to convey */
);
enum ast_presence_state state; /*!< The state associated with this presence state message */
};
int ast_presence_state_engine_init(void);
#endif