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

4 files changed, 35 insertions, 22 deletions

diff --git a/tests/test_cel.c b/tests/test_cel.c
index 31f73468c..395ec0ccc 100644
--- a/tests/test_cel.c
+++ b/tests/test_cel.c
@@ -224,8 +224,9 @@ static void do_sleep(void)
 	ast_hangup((channel)); \
 	HANGUP_EVENT(channel, cause, dialstatus); \
 	APPEND_EVENT(channel, AST_CEL_CHANNEL_END, NULL, NULL, NULL); \
-	ao2_cleanup(stasis_cache_get_extended(ast_channel_topic_all_cached(), \
-		ast_channel_snapshot_type(), ast_channel_uniqueid(channel), 1)); \
+	stasis_topic_wait(ast_channel_topic_all_cached()); \
+	ao2_cleanup(stasis_cache_get(ast_channel_cache(), \
+		ast_channel_snapshot_type(), ast_channel_uniqueid(channel))); \
 	ao2_cleanup(channel); \
 	channel = NULL; \
 	} while (0)
diff --git a/tests/test_devicestate.c b/tests/test_devicestate.c
index 4aff9394b..ff5d681f4 100644
--- a/tests/test_devicestate.c
+++ b/tests/test_devicestate.c
@@ -394,7 +394,7 @@ static void cache_cleanup(int unused)
 {
 	RAII_VAR(struct ao2_container *, cache_dump, NULL, ao2_cleanup);
 	/* remove all device states created during this test */
-	cache_dump = stasis_cache_dump(ast_device_state_topic_cached(), NULL);
+	cache_dump = stasis_cache_dump(ast_device_state_cache(), NULL);
 	if (!cache_dump) {
 		return;
 	}
@@ -434,7 +434,7 @@ AST_TEST_DEFINE(device_state_aggregation_test)
 	consumer = consumer_create();
 	ast_test_validate(test, NULL != consumer);
 
-	device_msg_router = stasis_message_router_create(stasis_caching_get_topic(ast_device_state_topic_cached()));
+	device_msg_router = stasis_message_router_create(ast_device_state_topic_cached());
 	ast_test_validate(test, NULL != device_msg_router);
 
 	ao2_ref(consumer, +1);
@@ -451,7 +451,7 @@ AST_TEST_DEFINE(device_state_aggregation_test)
 	ast_test_validate(test, AST_DEVICE_NOT_INUSE == consumer->state);
 	ast_test_validate(test, AST_DEVICE_NOT_INUSE == consumer->aggregate_state);
 
-	msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
+	msg = stasis_cache_get(ast_device_state_cache(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
 	device_state = stasis_message_data(msg);
 	ast_test_validate(test, AST_DEVICE_NOT_INUSE == device_state->state);
 	ao2_cleanup(msg);
@@ -466,7 +466,7 @@ AST_TEST_DEFINE(device_state_aggregation_test)
 	ast_test_validate(test, AST_DEVICE_NOT_INUSE == consumer->state);
 	ast_test_validate(test, AST_DEVICE_NOT_INUSE == consumer->aggregate_state);
 
-	msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
+	msg = stasis_cache_get(ast_device_state_cache(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
 	device_state = stasis_message_data(msg);
 	ast_test_validate(test, AST_DEVICE_NOT_INUSE == device_state->state);
 	ao2_cleanup(msg);
@@ -479,7 +479,7 @@ AST_TEST_DEFINE(device_state_aggregation_test)
 	ast_test_validate(test, AST_DEVICE_INUSE == consumer->state);
 	ast_test_validate(test, AST_DEVICE_INUSE == consumer->aggregate_state);
 
-	msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
+	msg = stasis_cache_get(ast_device_state_cache(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
 	device_state = stasis_message_data(msg);
 	ast_test_validate(test, AST_DEVICE_INUSE == device_state->state);
 	ao2_cleanup(msg);
@@ -492,7 +492,7 @@ AST_TEST_DEFINE(device_state_aggregation_test)
 	ast_test_validate(test, AST_DEVICE_RINGING == consumer->state);
 	ast_test_validate(test, AST_DEVICE_RINGINUSE == consumer->aggregate_state);
 
-	msg = stasis_cache_get(ast_device_state_topic_cached(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
+	msg = stasis_cache_get(ast_device_state_cache(), ast_device_state_message_type(), UNIT_TEST_DEVICE_IDENTIFIER);
 	device_state = stasis_message_data(msg);
 	ast_test_validate(test, AST_DEVICE_RINGINUSE == device_state->state);
 	ao2_cleanup(msg);
diff --git a/tests/test_stasis.c b/tests/test_stasis.c
index 663663355..0b63da42e 100644
--- a/tests/test_stasis.c
+++ b/tests/test_stasis.c
@@ -614,6 +614,7 @@ AST_TEST_DEFINE(cache_passthrough)
 {
 	RAII_VAR(struct stasis_message_type *, non_cache_type, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_topic *, topic, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_cache *, cache, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_caching_topic *, caching_topic, NULL, stasis_caching_unsubscribe);
 	RAII_VAR(struct consumer *, consumer, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_subscription *, sub, NULL, stasis_unsubscribe);
@@ -636,7 +637,9 @@ AST_TEST_DEFINE(cache_passthrough)
 	ast_test_validate(test, NULL != non_cache_type);
 	topic = stasis_topic_create("SomeTopic");
 	ast_test_validate(test, NULL != topic);
-	caching_topic = stasis_caching_topic_create(topic, cache_test_data_id);
+	cache = stasis_cache_create(cache_test_data_id);
+	ast_test_validate(test, NULL != cache);
+	caching_topic = stasis_caching_topic_create(topic, cache);
 	ast_test_validate(test, NULL != caching_topic);
 	consumer = consumer_create(1);
 	ast_test_validate(test, NULL != consumer);
@@ -664,6 +667,7 @@ AST_TEST_DEFINE(cache)
 {
 	RAII_VAR(struct stasis_message_type *, cache_type, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_topic *, topic, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_cache *, cache, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_caching_topic *, caching_topic, NULL, stasis_caching_unsubscribe);
 	RAII_VAR(struct consumer *, consumer, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_subscription *, sub, NULL, stasis_unsubscribe);
@@ -689,7 +693,9 @@ AST_TEST_DEFINE(cache)
 	ast_test_validate(test, NULL != cache_type);
 	topic = stasis_topic_create("SomeTopic");
 	ast_test_validate(test, NULL != topic);
-	caching_topic = stasis_caching_topic_create(topic, cache_test_data_id);
+	cache = stasis_cache_create(cache_test_data_id);
+	ast_test_validate(test, NULL != cache);
+	caching_topic = stasis_caching_topic_create(topic, cache);
 	ast_test_validate(test, NULL != caching_topic);
 	consumer = consumer_create(1);
 	ast_test_validate(test, NULL != consumer);
@@ -714,7 +720,7 @@ AST_TEST_DEFINE(cache)
 	ast_test_validate(test, topic == actual_update->topic);
 	ast_test_validate(test, NULL == actual_update->old_snapshot);
 	ast_test_validate(test, test_message1_1 == actual_update->new_snapshot);
-	ast_test_validate(test, test_message1_1 == stasis_cache_get(caching_topic, cache_type, "1"));
+	ast_test_validate(test, test_message1_1 == stasis_cache_get(cache, cache_type, "1"));
 	/* stasis_cache_get returned a ref, so unref test_message1_1 */
 	ao2_ref(test_message1_1, -1);
 
@@ -723,7 +729,7 @@ AST_TEST_DEFINE(cache)
 	ast_test_validate(test, topic == actual_update->topic);
 	ast_test_validate(test, NULL == actual_update->old_snapshot);
 	ast_test_validate(test, test_message2_1 == actual_update->new_snapshot);
-	ast_test_validate(test, test_message2_1 == stasis_cache_get(caching_topic, cache_type, "2"));
+	ast_test_validate(test, test_message2_1 == stasis_cache_get(cache, cache_type, "2"));
 	/* stasis_cache_get returned a ref, so unref test_message2_1 */
 	ao2_ref(test_message2_1, -1);
 
@@ -739,7 +745,7 @@ AST_TEST_DEFINE(cache)
 	ast_test_validate(test, topic == actual_update->topic);
 	ast_test_validate(test, test_message2_1 == actual_update->old_snapshot);
 	ast_test_validate(test, test_message2_2 == actual_update->new_snapshot);
-	ast_test_validate(test, test_message2_2 == stasis_cache_get(caching_topic, cache_type, "2"));
+	ast_test_validate(test, test_message2_2 == stasis_cache_get(cache, cache_type, "2"));
 	/* stasis_cache_get returned a ref, so unref test_message2_2 */
 	ao2_ref(test_message2_2, -1);
 
@@ -755,7 +761,7 @@ AST_TEST_DEFINE(cache)
 	ast_test_validate(test, topic == actual_update->topic);
 	ast_test_validate(test, test_message1_1 == actual_update->old_snapshot);
 	ast_test_validate(test, NULL == actual_update->new_snapshot);
-	ast_test_validate(test, NULL == stasis_cache_get(caching_topic, cache_type, "1"));
+	ast_test_validate(test, NULL == stasis_cache_get(cache, cache_type, "1"));
 
 	return AST_TEST_PASS;
 }
@@ -764,6 +770,7 @@ AST_TEST_DEFINE(cache_dump)
 {
 	RAII_VAR(struct stasis_message_type *, cache_type, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_topic *, topic, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_cache *, cache, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_caching_topic *, caching_topic, NULL, stasis_caching_unsubscribe);
 	RAII_VAR(struct consumer *, consumer, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_subscription *, sub, NULL, stasis_unsubscribe);
@@ -791,7 +798,9 @@ AST_TEST_DEFINE(cache_dump)
 	ast_test_validate(test, NULL != cache_type);
 	topic = stasis_topic_create("SomeTopic");
 	ast_test_validate(test, NULL != topic);
-	caching_topic = stasis_caching_topic_create(topic, cache_test_data_id);
+	cache = stasis_cache_create(cache_test_data_id);
+	ast_test_validate(test, NULL != cache);
+	caching_topic = stasis_caching_topic_create(topic, cache);
 	ast_test_validate(test, NULL != caching_topic);
 	consumer = consumer_create(1);
 	ast_test_validate(test, NULL != consumer);
@@ -811,7 +820,7 @@ AST_TEST_DEFINE(cache_dump)
 	ast_test_validate(test, 2 == actual_len);
 
 	/* Check the cache */
-	cache_dump = stasis_cache_dump(caching_topic, NULL);
+	cache_dump = stasis_cache_dump(cache, NULL);
 	ast_test_validate(test, NULL != cache_dump);
 	ast_test_validate(test, 2 == ao2_container_count(cache_dump));
 	i = ao2_iterator_init(cache_dump, 0);
@@ -829,7 +838,7 @@ AST_TEST_DEFINE(cache_dump)
 	ast_test_validate(test, 3 == actual_len);
 
 	/* Check the cache */
-	cache_dump = stasis_cache_dump(caching_topic, NULL);
+	cache_dump = stasis_cache_dump(cache, NULL);
 	ast_test_validate(test, NULL != cache_dump);
 	ast_test_validate(test, 2 == ao2_container_count(cache_dump));
 	i = ao2_iterator_init(cache_dump, 0);
@@ -847,7 +856,7 @@ AST_TEST_DEFINE(cache_dump)
 	ast_test_validate(test, 4 == actual_len);
 
 	/* Check the cache */
-	cache_dump = stasis_cache_dump(caching_topic, NULL);
+	cache_dump = stasis_cache_dump(cache, NULL);
 	ast_test_validate(test, NULL != cache_dump);
 	ast_test_validate(test, 1 == ao2_container_count(cache_dump));
 	i = ao2_iterator_init(cache_dump, 0);
@@ -858,7 +867,7 @@ AST_TEST_DEFINE(cache_dump)
 
 	/* Dump the cache to ensure that it has no subscription change items in it since those aren't cached */
 	ao2_cleanup(cache_dump);
-	cache_dump = stasis_cache_dump(caching_topic, stasis_subscription_change_type());
+	cache_dump = stasis_cache_dump(cache, stasis_subscription_change_type());
 	ast_test_validate(test, 0 == ao2_container_count(cache_dump));
 
 	return AST_TEST_PASS;
@@ -1019,7 +1028,8 @@ static const char *cache_simple(struct stasis_message *message) {
 AST_TEST_DEFINE(router_cache_updates)
 {
 	RAII_VAR(struct stasis_topic *, topic, NULL, ao2_cleanup);
-	RAII_VAR(struct stasis_caching_topic *, caching_topic, NULL, stasis_caching_unsubscribe);
+	RAII_VAR(struct stasis_cache *, cache, NULL, ao2_cleanup);
+	RAII_VAR(struct stasis_caching_topic *, caching_topic, NULL, stasis_caching_unsubscribe_and_join);
 	RAII_VAR(struct stasis_message_type *, test_message_type1, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_message_type *, test_message_type2, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_message_type *, test_message_type3, NULL, ao2_cleanup);
@@ -1051,7 +1061,9 @@ AST_TEST_DEFINE(router_cache_updates)
 	topic = stasis_topic_create("TestTopic");
 	ast_test_validate(test, NULL != topic);
 
-	caching_topic = stasis_caching_topic_create(topic, cache_simple);
+	cache = stasis_cache_create(cache_simple);
+	ast_test_validate(test, NULL != cache);
+	caching_topic = stasis_caching_topic_create(topic, cache);
 	ast_test_validate(test, NULL != caching_topic);
 
 	consumer1 = consumer_create(1);
diff --git a/tests/test_stasis_endpoints.c b/tests/test_stasis_endpoints.c
index 9fe3ecfad..c0be07ca8 100644
--- a/tests/test_stasis_endpoints.c
+++ b/tests/test_stasis_endpoints.c
@@ -152,7 +152,7 @@ AST_TEST_DEFINE(cache_clear)
 	ast_test_validate(test, NULL != sink);
 
 	sub = stasis_subscribe(
-		stasis_caching_get_topic(ast_endpoint_topic_all_cached()),
+		ast_endpoint_topic_all_cached(),
 		stasis_message_sink_cb(), sink);
 	ast_test_validate(test, NULL != sub);