This patch adds a new message bus API to Asterisk.

For the initial use of this bus, I took some work kmoore did creating
channel snapshots. So rather than create AMI events directly in the
channel code, this patch generates Stasis events, which manager.c uses
to then publish the AMI event.

This message bus provides a generic publish/subscribe mechanism within
Asterisk. This message bus is:

 - Loosely coupled; new message types can be added in seperate modules.
 - Easy to use; publishing and subscribing are straightforward
   operations.

In addition to basic publish/subscribe, the patch also provides
mechanisms for message forwarding, and for message caching.

(issue ASTERISK-20887)
(closes issue ASTERISK-20959)
Review: https://reviewboard.asterisk.org/r/2339/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@382685 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 21 insertions, 0 deletions

diff --git a/main/channel_internal_api.c b/main/channel_internal_api.c
index 3f892ddef..8cc2e6c62 100644
--- a/main/channel_internal_api.c
+++ b/main/channel_internal_api.c
@@ -195,6 +195,8 @@ struct ast_channel {
 	char dtmf_digit_to_emulate;			/*!< Digit being emulated */
 	char sending_dtmf_digit;			/*!< Digit this channel is currently sending out. (zero if not sending) */
 	struct timeval sending_dtmf_tv;		/*!< The time this channel started sending the current digit. (Invalid if sending_dtmf_digit is zero.) */
+	struct stasis_topic *topic;			/*!< Topic for all channel's events */
+	struct stasis_subscription *forwarder;		/*!< Subscription for event forwarding to all topic */
 };
 
 /* AST_DATA definitions, which will probably have to be re-thought since the channel will be opaque */
@@ -1364,6 +1366,12 @@ void ast_channel_internal_cleanup(struct ast_channel *chan)
 	}
 
 	ast_string_field_free_memory(chan);
+
+	stasis_unsubscribe(chan->forwarder);
+	chan->forwarder = NULL;
+
+	ao2_cleanup(chan->topic);
+	chan->topic = NULL;
 }
 
 void ast_channel_internal_finalize(struct ast_channel *chan)
@@ -1375,3 +1383,16 @@ int ast_channel_internal_is_finalized(struct ast_channel *chan)
 {
 	return chan->finalized;
 }
+
+struct stasis_topic *ast_channel_topic(struct ast_channel *chan)
+{
+	return chan->topic;
+}
+
+void ast_channel_internal_setup_topics(struct ast_channel *chan)
+{
+	ast_assert(chan->topic == NULL);
+	ast_assert(chan->forwarder == NULL);
+	chan->topic = stasis_topic_create(chan->uniqueid);
+	chan->forwarder = stasis_forward_all(chan->topic, ast_channel_topic_all());
+}