[asterisk-commits] dlee: branch 12 r400180 - in /branches/12: apps/ include/asterisk/ main/ res/...

SVN commits to the Asterisk project asterisk-commits at lists.digium.com
Mon Sep 30 13:39:39 CDT 2013


Author: dlee
Date: Mon Sep 30 13:39:34 2013
New Revision: 400180

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=400180
Log:
Optimize how Stasis forwards are dispatched

This patch optimizes how forwards are dispatched in Stasis.

Originally, forwards were dispatched as subscriptions that are invoked
on the publishing thread. This did not account for the vast number of
forwards we would end up having in the system, and the amount of work it
would take to walk though the forward subscriptions.

This patch modifies Stasis so that rather than walking the tree of
forwards on every dispatch, when forwards and subscriptions are changed,
the subscriber list for every topic in the tree is changed.

This has a couple of benefits. First, this reduces the workload of
dispatching messages. It also reduces contention when dispatching to
different topics that happen to forward to the same aggregation topic
(as happens with all of the channel, bridge and endpoint topics).

Since forwards are no longer subscriptions, the bulk of this patch is
simply changing stasis_subscription objects to stasis_forward objects
(which, admittedly, I should have done in the first place.)

Since this required me to yet again put in a growing array, I finally
abstracted that out into a set of ast_vector macros in
asterisk/vector.h.

Review: https://reviewboard.asterisk.org/r/2883/

Added:
    branches/12/include/asterisk/vector.h
      - copied unchanged from r400179, team/dlee/stasis-forward-optimization/include/asterisk/vector.h
Modified:
    branches/12/apps/app_queue.c
    branches/12/include/asterisk/stasis.h
    branches/12/main/cdr.c
    branches/12/main/cel.c
    branches/12/main/channel_internal_api.c
    branches/12/main/manager.c
    branches/12/main/manager_bridges.c
    branches/12/main/manager_channels.c
    branches/12/main/manager_mwi.c
    branches/12/main/manager_system.c
    branches/12/main/stasis.c
    branches/12/main/stasis_cache_pattern.c
    branches/12/res/stasis/app.c
    branches/12/tests/test_stasis.c
    branches/12/tests/test_stasis_endpoints.c

Modified: branches/12/apps/app_queue.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/apps/app_queue.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/apps/app_queue.c (original)
+++ branches/12/apps/app_queue.c Mon Sep 30 13:39:34 2013
@@ -10336,7 +10336,7 @@
 };
 
 static struct stasis_message_router *agent_router;
-static struct stasis_subscription *topic_forwarder;
+static struct stasis_forward *topic_forwarder;
 
 static int unload_module(void)
 {
@@ -10364,7 +10364,7 @@
 		stasis_message_router_remove(message_router, queue_agent_ringnoanswer_type());
 	}
 	stasis_message_router_unsubscribe_and_join(agent_router);
-	topic_forwarder = stasis_unsubscribe(topic_forwarder);
+	topic_forwarder = stasis_forward_cancel(topic_forwarder);
 
 	STASIS_MESSAGE_TYPE_CLEANUP(queue_caller_join_type);
 	STASIS_MESSAGE_TYPE_CLEANUP(queue_caller_leave_type);

Modified: branches/12/include/asterisk/stasis.h
URL: http://svnview.digium.com/svn/asterisk/branches/12/include/asterisk/stasis.h?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/include/asterisk/stasis.h (original)
+++ branches/12/include/asterisk/stasis.h Mon Sep 30 13:39:34 2013
@@ -464,6 +464,8 @@
 struct stasis_subscription *stasis_unsubscribe_and_join(
 	struct stasis_subscription *subscription);
 
+struct stasis_forward;
+
 /*!
  * \brief Create a subscription which forwards all messages from one topic to
  * another.
@@ -477,8 +479,10 @@
  * \return \c NULL on error.
  * \since 12
  */
-struct stasis_subscription *stasis_forward_all(struct stasis_topic *from_topic,
+struct stasis_forward *stasis_forward_all(struct stasis_topic *from_topic,
 	struct stasis_topic *to_topic);
+
+struct stasis_forward *stasis_forward_cancel(struct stasis_forward *forward);
 
 /*!
  * \brief Get the unique ID for the subscription.

Modified: branches/12/main/cdr.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/cdr.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/cdr.c (original)
+++ branches/12/main/cdr.c Mon Sep 30 13:39:34 2013
@@ -334,13 +334,13 @@
 static struct stasis_message_router *stasis_router;
 
 /*! \brief Our subscription for bridges */
-static struct stasis_subscription *bridge_subscription;
+static struct stasis_forward *bridge_subscription;
 
 /*! \brief Our subscription for channels */
-static struct stasis_subscription *channel_subscription;
+static struct stasis_forward *channel_subscription;
 
 /*! \brief Our subscription for parking */
-static struct stasis_subscription *parking_subscription;
+static struct stasis_forward *parking_subscription;
 
 /*! \brief The parent topic for all topics we want to aggregate for CDRs */
 static struct stasis_topic *cdr_topic;
@@ -3884,9 +3884,9 @@
 
 static void cdr_engine_cleanup(void)
 {
-	channel_subscription = stasis_unsubscribe_and_join(channel_subscription);
-	bridge_subscription = stasis_unsubscribe_and_join(bridge_subscription);
-	parking_subscription = stasis_unsubscribe_and_join(parking_subscription);
+	channel_subscription = stasis_forward_cancel(channel_subscription);
+	bridge_subscription = stasis_forward_cancel(bridge_subscription);
+	parking_subscription = stasis_forward_cancel(parking_subscription);
 	stasis_message_router_unsubscribe_and_join(stasis_router);
 	ao2_cleanup(cdr_topic);
 	cdr_topic = NULL;

Modified: branches/12/main/cel.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/cel.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/cel.c (original)
+++ branches/12/main/cel.c Mon Sep 30 13:39:34 2013
@@ -121,16 +121,16 @@
 static struct stasis_topic *cel_aggregation_topic;
 
 /*! Subscription for forwarding the channel caching topic */
-static struct stasis_subscription *cel_channel_forwarder;
+static struct stasis_forward *cel_channel_forwarder;
 
 /*! Subscription for forwarding the channel caching topic */
-static struct stasis_subscription *cel_bridge_forwarder;
+static struct stasis_forward *cel_bridge_forwarder;
 
 /*! Subscription for forwarding the parking topic */
-static struct stasis_subscription *cel_parking_forwarder;
+static struct stasis_forward *cel_parking_forwarder;
 
 /*! Subscription for forwarding the CEL-specific topic */
-static struct stasis_subscription *cel_cel_forwarder;
+static struct stasis_forward *cel_cel_forwarder;
 
 struct stasis_message_type *cel_generic_type(void);
 STASIS_MESSAGE_TYPE_DEFN(cel_generic_type);
@@ -1394,10 +1394,10 @@
 	cel_aggregation_topic = NULL;
 	ao2_cleanup(cel_topic);
 	cel_topic = NULL;
-	cel_channel_forwarder = stasis_unsubscribe_and_join(cel_channel_forwarder);
-	cel_bridge_forwarder = stasis_unsubscribe_and_join(cel_bridge_forwarder);
-	cel_parking_forwarder = stasis_unsubscribe_and_join(cel_parking_forwarder);
-	cel_cel_forwarder = stasis_unsubscribe_and_join(cel_cel_forwarder);
+	cel_channel_forwarder = stasis_forward_cancel(cel_channel_forwarder);
+	cel_bridge_forwarder = stasis_forward_cancel(cel_bridge_forwarder);
+	cel_parking_forwarder = stasis_forward_cancel(cel_parking_forwarder);
+	cel_cel_forwarder = stasis_forward_cancel(cel_cel_forwarder);
 	ast_cli_unregister(&cli_status);
 	ao2_cleanup(cel_dialstatus_store);
 	cel_dialstatus_store = NULL;

Modified: branches/12/main/channel_internal_api.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/channel_internal_api.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/channel_internal_api.c (original)
+++ branches/12/main/channel_internal_api.c Mon Sep 30 13:39:34 2013
@@ -207,8 +207,7 @@
 	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_cp_single *topics;		/*!< Topic for all channel's events */
-	struct stasis_subscription *forwarder;		/*!< Subscription for event forwarding to all topic */
-	struct stasis_subscription *endpoint_forward;	/*!< Subscription for event forwarding to endpoint's topic */
+	struct stasis_forward *endpoint_forward;	/*!< Subscription for event forwarding to endpoint's topic */
 };
 
 /*! \brief The monotonically increasing integer counter for channel uniqueids */
@@ -1429,8 +1428,7 @@
 
 	ast_string_field_free_memory(chan);
 
-	chan->forwarder = stasis_unsubscribe(chan->forwarder);
-	chan->endpoint_forward = stasis_unsubscribe(chan->endpoint_forward);
+	chan->endpoint_forward = stasis_forward_cancel(chan->endpoint_forward);
 
 	stasis_cp_single_unsubscribe(chan->topics);
 	chan->topics = NULL;

Modified: branches/12/main/manager.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/manager.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/manager.c (original)
+++ branches/12/main/manager.c Mon Sep 30 13:39:34 2013
@@ -1126,7 +1126,7 @@
 static struct stasis_message_router *stasis_router;
 
 /*! \brief The \ref stasis_subscription for forwarding the RTP topic to the AMI topic */
-static struct stasis_subscription *rtp_topic_forwarder;
+static struct stasis_forward *rtp_topic_forwarder;
 
 #define MGR_SHOW_TERMINAL_WIDTH 80
 
@@ -7759,7 +7759,7 @@
 		stasis_message_router_unsubscribe_and_join(stasis_router);
 		stasis_router = NULL;
 	}
-	stasis_unsubscribe_and_join(rtp_topic_forwarder);
+	stasis_forward_cancel(rtp_topic_forwarder);
 	rtp_topic_forwarder = NULL;
 	ao2_cleanup(manager_topic);
 	manager_topic = NULL;

Modified: branches/12/main/manager_bridges.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/manager_bridges.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/manager_bridges.c (original)
+++ branches/12/main/manager_bridges.c Mon Sep 30 13:39:34 2013
@@ -106,7 +106,7 @@
 /*! \brief The \ref stasis subscription returned by the forwarding of the channel topic
  * to the manager topic
  */
-static struct stasis_subscription *topic_forwarder;
+static struct stasis_forward *topic_forwarder;
 
 struct ast_str *ast_manager_build_bridge_state_string_prefix(
 	const struct ast_bridge_snapshot *snapshot,
@@ -456,7 +456,7 @@
 
 static void manager_bridging_cleanup(void)
 {
-	stasis_unsubscribe(topic_forwarder);
+	stasis_forward_cancel(topic_forwarder);
 	topic_forwarder = NULL;
 }
 

Modified: branches/12/main/manager_channels.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/manager_channels.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/manager_channels.c (original)
+++ branches/12/main/manager_channels.c Mon Sep 30 13:39:34 2013
@@ -370,7 +370,7 @@
 /*! \brief The \ref stasis subscription returned by the forwarding of the channel topic
  * to the manager topic
  */
-static struct stasis_subscription *topic_forwarder;
+static struct stasis_forward *topic_forwarder;
 
 struct ast_str *ast_manager_build_channel_state_string_prefix(
 		const struct ast_channel_snapshot *snapshot,
@@ -1100,7 +1100,7 @@
 
 static void manager_channels_shutdown(void)
 {
-	stasis_unsubscribe(topic_forwarder);
+	stasis_forward_cancel(topic_forwarder);
 	topic_forwarder = NULL;
 }
 

Modified: branches/12/main/manager_mwi.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/manager_mwi.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/manager_mwi.c (original)
+++ branches/12/main/manager_mwi.c Mon Sep 30 13:39:34 2013
@@ -41,7 +41,7 @@
 /*! \brief The \ref stasis subscription returned by the forwarding of the MWI topic
  * to the manager topic
  */
-static struct stasis_subscription *topic_forwarder;
+static struct stasis_forward *topic_forwarder;
 
 /*! \brief Callback function used by \ref mwi_app_event_cb to weed out "Event" keys */
 static int exclude_event_cb(const char *key)
@@ -149,7 +149,7 @@
 
 static void manager_mwi_shutdown(void)
 {
-	stasis_unsubscribe(topic_forwarder);
+	stasis_forward_cancel(topic_forwarder);
 	topic_forwarder = NULL;
 }
 

Modified: branches/12/main/manager_system.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/manager_system.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/manager_system.c (original)
+++ branches/12/main/manager_system.c Mon Sep 30 13:39:34 2013
@@ -34,11 +34,11 @@
 /*! \brief The \ref stasis subscription returned by the forwarding of the system topic
  * to the manager topic
  */
-static struct stasis_subscription *topic_forwarder;
+static struct stasis_forward *topic_forwarder;
 
 static void manager_system_shutdown(void)
 {
-	stasis_unsubscribe(topic_forwarder);
+	stasis_forward_cancel(topic_forwarder);
 	topic_forwarder = NULL;
 }
 

Modified: branches/12/main/stasis.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/stasis.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/stasis.c (original)
+++ branches/12/main/stasis.c Mon Sep 30 13:39:34 2013
@@ -29,7 +29,7 @@
 
 #include "asterisk.h"
 
-ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$");
 
 #include "asterisk/astobj2.h"
 #include "asterisk/stasis_internal.h"
@@ -37,6 +37,7 @@
 #include "asterisk/taskprocessor.h"
 #include "asterisk/utils.h"
 #include "asterisk/uuid.h"
+#include "asterisk/vector.h"
 
 /*!
  * \page stasis-impl Stasis Implementation Notes
@@ -139,15 +140,17 @@
 struct stasis_topic {
 	char *name;
 	/*! Variable length array of the subscribers */
-	struct stasis_subscription **subscribers;
-	/*! Allocated length of the subscribers array */
-	size_t num_subscribers_max;
-	/*! Current size of the subscribers array */
-	size_t num_subscribers_current;
+	ast_vector(struct stasis_subscription *) subscribers;
+
+	/*! Topics forwarding into this topic */
+	ast_vector(struct stasis_topic *) upstream_topics;
 };
 
 /* Forward declarations for the tightly-coupled subscription object */
-static int topic_add_subscription(struct stasis_topic *topic, struct stasis_subscription *sub);
+static int topic_add_subscription(struct stasis_topic *topic,
+	struct stasis_subscription *sub);
+
+static int topic_remove_subscription(struct stasis_topic *topic, struct stasis_subscription *sub);
 
 static void topic_dtor(void *obj)
 {
@@ -155,16 +158,18 @@
 
 	/* Subscribers hold a reference to topics, so they should all be
 	 * unsubscribed before we get here. */
-	ast_assert(topic->num_subscribers_current == 0);
+	ast_assert(ast_vector_size(topic->subscribers) == 0);
 	ast_free(topic->name);
 	topic->name = NULL;
-	ast_free(topic->subscribers);
-	topic->subscribers = NULL;
+
+	ast_vector_free(topic->subscribers);
+	ast_vector_free(topic->upstream_topics);
 }
 
 struct stasis_topic *stasis_topic_create(const char *name)
 {
 	RAII_VAR(struct stasis_topic *, topic, NULL, ao2_cleanup);
+	int res = 0;
 
 	topic = ao2_alloc(sizeof(*topic), topic_dtor);
 
@@ -177,9 +182,10 @@
 		return NULL;
 	}
 
-	topic->num_subscribers_max = INITIAL_SUBSCRIBERS_MAX;
-	topic->subscribers = ast_calloc(topic->num_subscribers_max, sizeof(*topic->subscribers));
-	if (!topic->subscribers) {
+	res |= ast_vector_init(topic->subscribers, INITIAL_SUBSCRIBERS_MAX);
+	res |= ast_vector_init(topic->upstream_topics, 0);
+
+	if (res != 0) {
 		return NULL;
 	}
 
@@ -264,7 +270,8 @@
 	}
 }
 
-static void send_subscription_change_message(struct stasis_topic *topic, char *uniqueid, char *description);
+static void send_subscription_subscribe(struct stasis_topic *topic, struct stasis_subscription *sub);
+static void send_subscription_unsubscribe(struct stasis_topic *topic, struct stasis_subscription *sub);
 
 struct stasis_subscription *internal_stasis_subscribe(
 	struct stasis_topic *topic,
@@ -306,7 +313,7 @@
 	if (topic_add_subscription(topic, sub) != 0) {
 		return NULL;
 	}
-	send_subscription_change_message(topic, sub->uniqueid, "Subscribe");
+	send_subscription_subscribe(topic, sub);
 
 	ao2_ref(sub, +1);
 	return sub;
@@ -322,27 +329,28 @@
 
 struct stasis_subscription *stasis_unsubscribe(struct stasis_subscription *sub)
 {
-	if (sub) {
-		size_t i;
-		/* The subscription may be the last ref to this topic. Hold
-		 * the topic ref open until after the unlock. */
-		RAII_VAR(struct stasis_topic *, topic, ao2_bump(sub->topic),
-			ao2_cleanup);
-		SCOPED_AO2LOCK(lock_topic, topic);
-
-		for (i = 0; i < topic->num_subscribers_current; ++i) {
-			if (topic->subscribers[i] == sub) {
-				send_subscription_change_message(topic, sub->uniqueid, "Unsubscribe");
-				/* swap [i] with last entry; remove last entry */
-				topic->subscribers[i] = topic->subscribers[--topic->num_subscribers_current];
-				/* Unsubscribing unrefs the subscription */
-				ao2_cleanup(sub);
-				return NULL;
-			}
-		}
-
-		ast_log(LOG_ERROR, "Internal error: subscription has invalid topic\n");
-	}
+	/* The subscription may be the last ref to this topic. Hold
+	 * the topic ref open until after the unlock. */
+	RAII_VAR(struct stasis_topic *, topic,
+		ao2_bump(sub ? sub->topic : NULL), ao2_cleanup);
+
+	if (!sub) {
+		return NULL;
+	}
+
+	/* We have to remove the subscription first, to ensure the unsubscribe
+	 * is the final message */
+	if (topic_remove_subscription(sub->topic, sub) != 0) {
+		ast_log(LOG_ERROR,
+			"Internal error: subscription has invalid topic\n");
+		return NULL;
+	}
+
+	/* Now let everyone know about the unsubscribe */
+	send_subscription_unsubscribe(topic, sub);
+
+	/* Unsubscribing unrefs the subscription */
+	ao2_cleanup(sub);
 	return NULL;
 }
 
@@ -392,8 +400,8 @@
 		struct stasis_topic *topic = sub->topic;
 		SCOPED_AO2LOCK(lock_topic, topic);
 
-		for (i = 0; i < topic->num_subscribers_current; ++i) {
-			if (topic->subscribers[i] == sub) {
+		for (i = 0; i < ast_vector_size(topic->subscribers); ++i) {
+			if (ast_vector_get(topic->subscribers, i) == sub) {
 				return 1;
 			}
 		}
@@ -435,18 +443,8 @@
  */
 static int topic_add_subscription(struct stasis_topic *topic, struct stasis_subscription *sub)
 {
-	struct stasis_subscription **subscribers;
+	size_t idx;
 	SCOPED_AO2LOCK(lock, topic);
-
-	/* Increase list size, if needed */
-	if (topic->num_subscribers_current + 1 > topic->num_subscribers_max) {
-		subscribers = realloc(topic->subscribers, 2 * topic->num_subscribers_max * sizeof(*subscribers));
-		if (!subscribers) {
-			return -1;
-		}
-		topic->subscribers = subscribers;
-		topic->num_subscribers_max *= 2;
-	}
 
 	/* The reference from the topic to the subscription is shared with
 	 * the owner of the subscription, which will explicitly unsubscribe
@@ -454,8 +452,27 @@
 	 *
 	 * If we bumped the refcount here, the owner would have to unsubscribe
 	 * and cleanup, which is a bit awkward. */
-	topic->subscribers[topic->num_subscribers_current++] = sub;
+	ast_vector_append(topic->subscribers, sub);
+
+	for (idx = 0; idx < ast_vector_size(topic->upstream_topics); ++idx) {
+		topic_add_subscription(
+			ast_vector_get(topic->upstream_topics, idx), sub);
+	}
+
 	return 0;
+}
+
+static int topic_remove_subscription(struct stasis_topic *topic, struct stasis_subscription *sub)
+{
+	size_t idx;
+	SCOPED_AO2LOCK(lock_topic, topic);
+
+	for (idx = 0; idx < ast_vector_size(topic->upstream_topics); ++idx) {
+		topic_remove_subscription(
+			ast_vector_get(topic->upstream_topics, idx), sub);
+	}
+
+	return ast_vector_remove_elem_unordered(topic->subscribers, sub);
 }
 
 /*!
@@ -520,6 +537,30 @@
 	return 0;
 }
 
+static void dispatch_message(struct stasis_subscription *sub,
+	struct stasis_topic *publisher_topic, struct stasis_message *message)
+{
+	if (sub->mailbox) {
+		struct dispatch *dispatch;
+
+		dispatch = dispatch_create(publisher_topic, message, sub);
+		if (!dispatch) {
+			ast_log(LOG_DEBUG, "Dropping dispatch\n");
+			return;
+		}
+
+		if (ast_taskprocessor_push(sub->mailbox, dispatch_exec, dispatch) != 0) {
+			/* Push failed; just delete the dispatch.
+			 */
+			ast_log(LOG_DEBUG, "Dropping dispatch\n");
+			dispatch_dtor(dispatch);
+		}
+	} else {
+		/* Dispatch directly */
+		subscription_invoke(sub, publisher_topic, message);
+	}
+}
+
 void stasis_forward_message(struct stasis_topic *_topic, struct stasis_topic *publisher_topic, struct stasis_message *message)
 {
 	size_t i;
@@ -533,66 +574,106 @@
 	ast_assert(publisher_topic != NULL);
 	ast_assert(message != NULL);
 
-	for (i = 0; i < topic->num_subscribers_current; ++i) {
-		struct stasis_subscription *sub = topic->subscribers[i];
+	for (i = 0; i < ast_vector_size(topic->subscribers); ++i) {
+		struct stasis_subscription *sub = ast_vector_get(topic->subscribers, i);
 
 		ast_assert(sub != NULL);
 
-		if (sub->mailbox) {
-			struct dispatch *dispatch;
-
-			dispatch = dispatch_create(publisher_topic, message, sub);
-			if (!dispatch) {
-				ast_log(LOG_ERROR, "Dropping dispatch\n");
-				break;
+		dispatch_message(sub, publisher_topic, message);
+	}
+}
+
+void stasis_publish(struct stasis_topic *topic, struct stasis_message *message)
+{
+	stasis_forward_message(topic, topic, message);
+}
+
+/*!
+ * \brief Forwarding information
+ *
+ * Any message posted to \a from_topic is forwarded to \a to_topic.
+ *
+ * In cases where both the \a from_topic and \a to_topic need to be locked,
+ * always lock the \a to_topic first, then the \a from_topic. Lest you deadlock.
+ */
+struct stasis_forward {
+	/*! Originating topic */
+	struct stasis_topic *from_topic;
+	/*! Destination topic */
+	struct stasis_topic *to_topic;
+};
+
+static void forward_dtor(void *obj)
+{
+	struct stasis_forward *forward = obj;
+
+	ao2_cleanup(forward->from_topic);
+	forward->from_topic = NULL;
+	ao2_cleanup(forward->to_topic);
+	forward->to_topic = NULL;
+}
+
+struct stasis_forward *stasis_forward_cancel(struct stasis_forward *forward)
+{
+	if (forward) {
+		int idx;
+
+		struct stasis_topic *from = forward->from_topic;
+		struct stasis_topic *to = forward->to_topic;
+
+		SCOPED_AO2LOCK(to_lock, to);
+
+		ast_vector_remove_elem_unordered(to->upstream_topics, from);
+
+		ao2_lock(from);
+		for (idx = 0; idx < ast_vector_size(to->subscribers); ++idx) {
+			topic_remove_subscription(
+				from, ast_vector_get(to->subscribers, idx));
+		}
+		ao2_unlock(from);
+	}
+
+	ao2_cleanup(forward);
+
+	return NULL;
+}
+
+struct stasis_forward *stasis_forward_all(struct stasis_topic *from_topic,
+	struct stasis_topic *to_topic)
+{
+	RAII_VAR(struct stasis_forward *, forward, NULL, ao2_cleanup);
+
+	if (!from_topic || !to_topic) {
+		return NULL;
+	}
+
+	forward = ao2_alloc(sizeof(*forward), forward_dtor);
+	if (!forward) {
+		return NULL;
+	}
+
+	forward->from_topic = ao2_bump(from_topic);
+	forward->to_topic = ao2_bump(to_topic);
+
+	{
+		SCOPED_AO2LOCK(lock, to_topic);
+		int res;
+
+		res = ast_vector_append(to_topic->upstream_topics, from_topic);
+		if (res != 0) {
+			return NULL;
+		}
+
+		{
+			SCOPED_AO2LOCK(lock, from_topic);
+			size_t idx;
+			for (idx = 0; idx < ast_vector_size(to_topic->subscribers); ++idx) {
+				topic_add_subscription(from_topic, ast_vector_get(to_topic->subscribers, idx));
 			}
-
-			if (ast_taskprocessor_push(sub->mailbox, dispatch_exec, dispatch) != 0) {
-				/* Push failed; just delete the dispatch.
-				 */
-				ast_log(LOG_ERROR, "Dropping dispatch\n");
-				dispatch_dtor(dispatch);
-			}
-		} else {
-			/* Dispatch directly */
-			subscription_invoke(sub, publisher_topic, message);
 		}
 	}
-}
-
-void stasis_publish(struct stasis_topic *topic, struct stasis_message *message)
-{
-	stasis_forward_message(topic, topic, message);
-}
-
-/*! \brief Forwarding subscriber */
-static void stasis_forward_cb(void *data, struct stasis_subscription *sub, struct stasis_topic *topic, struct stasis_message *message)
-{
-	struct stasis_topic *to_topic = data;
-	stasis_forward_message(to_topic, topic, message);
-
-	if (stasis_subscription_final_message(sub, message)) {
-		ao2_cleanup(to_topic);
-	}
-}
-
-struct stasis_subscription *stasis_forward_all(struct stasis_topic *from_topic, struct stasis_topic *to_topic)
-{
-	struct stasis_subscription *sub;
-	if (!from_topic || !to_topic) {
-		return NULL;
-	}
-
-	/* Forwarding subscriptions should dispatch directly instead of having a
-	 * mailbox. Otherwise, messages forwarded to the same topic from
-	 * different topics may get reordered. Which is bad.
-	 */
-	sub = internal_stasis_subscribe(from_topic, stasis_forward_cb, to_topic, 0);
-	if (sub) {
-		/* hold a ref to to_topic for this forwarding subscription */
-		ao2_ref(to_topic, +1);
-	}
-	return sub;
+
+	return ao2_bump(forward);
 }
 
 static void subscription_change_dtor(void *obj)
@@ -602,7 +683,7 @@
 	ao2_cleanup(change->topic);
 }
 
-static struct stasis_subscription_change *subscription_change_alloc(struct stasis_topic *topic, char *uniqueid, char *description)
+static struct stasis_subscription_change *subscription_change_alloc(struct stasis_topic *topic, const char *uniqueid, const char *description)
 {
 	RAII_VAR(struct stasis_subscription_change *, change, NULL, ao2_cleanup);
 
@@ -620,12 +701,15 @@
 	return change;
 }
 
-static void send_subscription_change_message(struct stasis_topic *topic, char *uniqueid, char *description)
+static void send_subscription_subscribe(struct stasis_topic *topic, struct stasis_subscription *sub)
 {
 	RAII_VAR(struct stasis_subscription_change *, change, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
 
-	change = subscription_change_alloc(topic, uniqueid, description);
+	/* This assumes that we have already unsubscribed */
+	ast_assert(stasis_subscription_is_subscribed(sub));
+
+	change = subscription_change_alloc(topic, sub->uniqueid, "Subscribe");
 
 	if (!change) {
 		return;
@@ -640,15 +724,42 @@
 	stasis_publish(topic, msg);
 }
 
+static void send_subscription_unsubscribe(struct stasis_topic *topic,
+	struct stasis_subscription *sub)
+{
+	RAII_VAR(struct stasis_subscription_change *, change, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
+
+	/* This assumes that we have already unsubscribed */
+	ast_assert(!stasis_subscription_is_subscribed(sub));
+
+	change = subscription_change_alloc(topic, sub->uniqueid, "Unsubscribe");
+
+	if (!change) {
+		return;
+	}
+
+	msg = stasis_message_create(stasis_subscription_change_type(), change);
+
+	if (!msg) {
+		return;
+	}
+
+	stasis_publish(topic, msg);
+
+	/* Now we have to dispatch to the subscription itself */
+	dispatch_message(sub, topic, msg);
+}
+
 struct topic_pool_entry {
-	struct stasis_subscription *forward;
+	struct stasis_forward *forward;
 	struct stasis_topic *topic;
 };
 
 static void topic_pool_entry_dtor(void *obj)
 {
 	struct topic_pool_entry *entry = obj;
-	entry->forward = stasis_unsubscribe(entry->forward);
+	entry->forward = stasis_forward_cancel(entry->forward);
 	ao2_cleanup(entry->topic);
 	entry->topic = NULL;
 }

Modified: branches/12/main/stasis_cache_pattern.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/main/stasis_cache_pattern.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/main/stasis_cache_pattern.c (original)
+++ branches/12/main/stasis_cache_pattern.c Mon Sep 30 13:39:34 2013
@@ -39,15 +39,15 @@
 	struct stasis_topic *topic_cached;
 	struct stasis_cache *cache;
 
-	struct stasis_subscription *forward_all_to_cached;
+	struct stasis_forward *forward_all_to_cached;
 };
 
 struct stasis_cp_single {
 	struct stasis_topic *topic;
 	struct stasis_caching_topic *topic_cached;
 
-	struct stasis_subscription *forward_topic_to_all;
-	struct stasis_subscription *forward_cached_to_all;
+	struct stasis_forward *forward_topic_to_all;
+	struct stasis_forward *forward_cached_to_all;
 };
 
 static void all_dtor(void *obj)
@@ -60,7 +60,7 @@
 	all->topic_cached = NULL;
 	ao2_cleanup(all->cache);
 	all->cache = NULL;
-	stasis_unsubscribe_and_join(all->forward_all_to_cached);
+	stasis_forward_cancel(all->forward_all_to_cached);
 	all->forward_all_to_cached = NULL;
 }
 
@@ -172,9 +172,9 @@
 		return;
 	}
 
-	stasis_unsubscribe(one->forward_topic_to_all);
+	stasis_forward_cancel(one->forward_topic_to_all);
 	one->forward_topic_to_all = NULL;
-	stasis_unsubscribe(one->forward_cached_to_all);
+	stasis_forward_cancel(one->forward_cached_to_all);
 	one->forward_cached_to_all = NULL;
 	stasis_caching_unsubscribe(one->topic_cached);
 	one->topic_cached = NULL;

Modified: branches/12/res/stasis/app.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/res/stasis/app.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/res/stasis/app.c (original)
+++ branches/12/res/stasis/app.c Mon Sep 30 13:39:34 2013
@@ -58,9 +58,9 @@
 	int interested;
 
 	/*! Forward for the regular topic */
-	struct stasis_subscription *topic_forward;
+	struct stasis_forward *topic_forward;
 	/*! Forward for the caching topic */
-	struct stasis_subscription *topic_cached_forward;
+	struct stasis_forward *topic_cached_forward;
 
 	/*! Unique id of the object being forwarded */
 	char id[];
@@ -78,9 +78,9 @@
 
 static void forwards_unsubscribe(struct app_forwards *forwards)
 {
-	stasis_unsubscribe(forwards->topic_forward);
+	stasis_forward_cancel(forwards->topic_forward);
 	forwards->topic_forward = NULL;
-	stasis_unsubscribe(forwards->topic_cached_forward);
+	stasis_forward_cancel(forwards->topic_cached_forward);
 	forwards->topic_cached_forward = NULL;
 }
 
@@ -129,7 +129,7 @@
 		ast_channel_topic_cached(chan), app->topic);
 	if (!forwards->topic_cached_forward) {
 		/* Half-subscribed is a bad thing */
-		stasis_unsubscribe(forwards->topic_forward);
+		stasis_forward_cancel(forwards->topic_forward);
 		forwards->topic_forward = NULL;
 		return NULL;
 	}
@@ -163,7 +163,7 @@
 		ast_bridge_topic_cached(bridge), app->topic);
 	if (!forwards->topic_cached_forward) {
 		/* Half-subscribed is a bad thing */
-		stasis_unsubscribe(forwards->topic_forward);
+		stasis_forward_cancel(forwards->topic_forward);
 		forwards->topic_forward = NULL;
 		return NULL;
 	}

Modified: branches/12/tests/test_stasis.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/tests/test_stasis.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/tests/test_stasis.c (original)
+++ branches/12/tests/test_stasis.c Mon Sep 30 13:39:34 2013
@@ -427,7 +427,7 @@
 	RAII_VAR(struct consumer *, parent_consumer, NULL, ao2_cleanup);
 	RAII_VAR(struct consumer *, consumer, NULL, ao2_cleanup);
 
-	RAII_VAR(struct stasis_subscription *, forward_sub, NULL, stasis_unsubscribe);
+	RAII_VAR(struct stasis_forward *, forward_sub, NULL, stasis_forward_cancel);
 	RAII_VAR(struct stasis_subscription *, parent_sub, NULL, stasis_unsubscribe);
 	RAII_VAR(struct stasis_subscription *, sub, NULL, stasis_unsubscribe);
 
@@ -499,8 +499,8 @@
 	RAII_VAR(struct stasis_message *, test_message2, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_message *, test_message3, NULL, ao2_cleanup);
 
-	RAII_VAR(struct stasis_subscription *, forward_sub1, NULL, stasis_unsubscribe);
-	RAII_VAR(struct stasis_subscription *, forward_sub2, NULL, stasis_unsubscribe);
+	RAII_VAR(struct stasis_forward *, forward_sub1, NULL, stasis_forward_cancel);
+	RAII_VAR(struct stasis_forward *, forward_sub2, NULL, stasis_forward_cancel);
 	RAII_VAR(struct stasis_subscription *, sub, NULL, stasis_unsubscribe);
 
 	RAII_VAR(struct consumer *, consumer, NULL, ao2_cleanup);

Modified: branches/12/tests/test_stasis_endpoints.c
URL: http://svnview.digium.com/svn/asterisk/branches/12/tests/test_stasis_endpoints.c?view=diff&rev=400180&r1=400179&r2=400180
==============================================================================
--- branches/12/tests/test_stasis_endpoints.c (original)
+++ branches/12/tests/test_stasis_endpoints.c Mon Sep 30 13:39:34 2013
@@ -264,11 +264,14 @@
 	type = stasis_message_type(msg);
 	ast_test_validate(test, ast_channel_snapshot_type() == type);
 
+	/* The ordering of the cache clear and endpoint snapshot are
+	 * unspecified */
 	msg = sink->messages[3];
-	type = stasis_message_type(msg);
-	ast_test_validate(test, stasis_cache_clear_type() == type);
-
-	msg = sink->messages[4];
+	if (stasis_message_type(msg) == stasis_cache_clear_type()) {
+		/* Okay; the next message should be the endpoint snapshot */
+		msg = sink->messages[4];
+	}
+
 	type = stasis_message_type(msg);
 	ast_test_validate(test, ast_endpoint_snapshot_type() == type);
 	actual_snapshot = stasis_message_data(msg);




More information about the asterisk-commits mailing list