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

1 files changed, 1 insertions, 1 deletions

diff --git a/channels/sig_pri.c b/channels/sig_pri.c
index f281f4498..e24752b9f 100644
--- a/channels/sig_pri.c
+++ b/channels/sig_pri.c
@@ -8956,7 +8956,7 @@ static void sig_pri_mwi_cache_update(struct sig_pri_span *pri)
 		ast_str_reset(uniqueid);
 		ast_str_set(&uniqueid, 0, "%s@%s", pri->mbox[idx].number, pri->mbox[idx].context);
 
-		msg = stasis_cache_get(ast_mwi_topic_cached(), ast_mwi_state_type(), ast_str_buffer(uniqueid));
+		msg = stasis_cache_get(ast_mwi_state_cache(), ast_mwi_state_type(), ast_str_buffer(uniqueid));
 		if (!msg) {
 			/* No cached event for this mailbox. */
 			continue;