Add vtable and methods for to_json and to_ami for Stasis messages

When a Stasis message type is defined in a loadable module, handling
those messages for AMI and res_stasis events can be cumbersome.

This patch adds a vtable to stasis_message_type, with to_ami and
to_json virtual functions. These allow messages to be handled
abstractly without putting module-specific code in core.

As an example, the VarSet AMI event was refactored to use the to_ami
virtual function.

(closes issue ASTERISK-21817)
Review: https://reviewboard.asterisk.org/r/2579/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@391403 65c4cc65-6c06-0410-ace0-fbb531ad65f3

5 files changed, 138 insertions, 85 deletions

diff --git a/main/manager.c b/main/manager.c
index b8e55de4f..eb01cc536 100644
--- a/main/manager.c
+++ b/main/manager.c
@@ -1313,6 +1313,23 @@ struct ast_str *ast_manager_str_from_json_object(struct ast_json *blob, key_excl
 	return output_str;
 }
 
+static void manager_default_msg_cb(void *data, struct stasis_subscription *sub,
+				    struct stasis_topic *topic,
+				    struct stasis_message *message)
+{
+	RAII_VAR(struct ast_manager_event_blob *, ev, NULL, ao2_cleanup);
+
+	ev = stasis_message_to_ami(message);
+
+	if (ev == NULL) {
+		/* Not and AMI message; disregard */
+		return;
+	}
+
+	manager_event(ev->event_flags, ev->manager_event, "%s",
+		ev->extra_fields);
+}
+
 static void manager_generic_msg_cb(void *data, struct stasis_subscription *sub,
 				    struct stasis_topic *topic,
 				    struct stasis_message *message)
@@ -7686,7 +7703,12 @@ static void manager_shutdown(void)
  */
 static int manager_subscriptions_init(void)
 {
-	STASIS_MESSAGE_TYPE_INIT(ast_manager_get_generic_type);
+	int res;
+
+	res = STASIS_MESSAGE_TYPE_INIT(ast_manager_get_generic_type);
+	if (res != 0) {
+		return -1;
+	}
 	manager_topic = stasis_topic_create("manager_topic");
 	if (!manager_topic) {
 		return -1;
@@ -7696,10 +7718,13 @@ static int manager_subscriptions_init(void)
 		return -1;
 	}
 
-	if (stasis_message_router_add(stasis_router,
-					 ast_manager_get_generic_type(),
-					 manager_generic_msg_cb,
-					 NULL)) {
+	res |= stasis_message_router_set_default(stasis_router,
+		manager_default_msg_cb, NULL);
+
+	res |= stasis_message_router_add(stasis_router,
+		ast_manager_get_generic_type(), manager_generic_msg_cb, NULL);
+
+	if (res != 0) {
 		return -1;
 	}
 	return 0;
diff --git a/main/manager_channels.c b/main/manager_channels.c
index b6eeb60b0..277dc873d 100644
--- a/main/manager_channels.c
+++ b/main/manager_channels.c
@@ -710,49 +710,6 @@ static void channel_snapshot_update(void *data, struct stasis_subscription *sub,
 	}
 }
 
-static void channel_varset_cb(void *data, struct stasis_subscription *sub,
-	struct stasis_topic *topic, struct stasis_message *message)
-{
-	struct ast_channel_blob *obj = stasis_message_data(message);
-	RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);
-	const char *variable = ast_json_string_get(ast_json_object_get(obj->blob, "variable"));
-	const char *value = ast_json_string_get(ast_json_object_get(obj->blob, "value"));
-
-	if (obj->snapshot) {
-		channel_event_string = ast_manager_build_channel_state_string(obj->snapshot);
-	} else {
-		channel_event_string = ast_str_create(35);
-		ast_str_set(&channel_event_string, 0,
-			    "Channel: none\r\n"
-			    "Uniqueid: none\r\n");
-	}
-
-	if (!channel_event_string) {
-		return;
-	}
-
-	/*** DOCUMENTATION
-		<managerEventInstance>
-			<synopsis>Raised when a variable is set to a particular value.</synopsis>
-			<syntax>
-				<xi:include xpointer="xpointer(/docs/managerEvent[@name='Newchannel']/managerEventInstance/syntax/parameter)" />
-				<parameter name="Variable">
-					<para>The variable being set.</para>
-				</parameter>
-				<parameter name="Value">
-					<para>The new value of the variable.</para>
-				</parameter>
-			</syntax>
-		</managerEventInstance>
-	***/
-	manager_event(EVENT_FLAG_DIALPLAN, "VarSet",
-		      "%s"
-		      "Variable: %s\r\n"
-		      "Value: %s\r\n",
-		      ast_str_buffer(channel_event_string),
-		      variable, value);
-}
-
 static int userevent_exclusion_cb(const char *key)
 {
 	if (!strcmp("type", key)) {
@@ -1280,11 +1237,6 @@ int manager_channels_init(void)
 					 NULL);
 
 	ret |= stasis_message_router_add(message_router,
-					 ast_channel_varset_type(),
-					 channel_varset_cb,
-					 NULL);
-
-	ret |= stasis_message_router_add(message_router,
 					 ast_channel_user_event_type(),
 					 channel_user_event_cb,
 					 NULL);
diff --git a/main/parking.c b/main/parking.c
index 2a5b72e61..a7cd0ba54 100644
--- a/main/parking.c
+++ b/main/parking.c
@@ -35,7 +35,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/channel.h"
 
 /*! \brief Message type for parked calls */
-static struct stasis_message_type *parked_call_type;
+STASIS_MESSAGE_TYPE_DEFN(ast_parked_call_type);
 
 /*! \brief Topic for parking lots */
 static struct stasis_topic *parking_topic;
@@ -48,15 +48,14 @@ static ast_bridge_channel_park_fn ast_bridge_channel_park_func = NULL;
 
 void ast_parking_stasis_init(void)
 {
-	parked_call_type = stasis_message_type_create("ast_parked_call");
+	STASIS_MESSAGE_TYPE_INIT(ast_parked_call_type);
 	parking_topic = stasis_topic_create("ast_parking");
 }
 
 void ast_parking_stasis_disable(void)
 {
-	ao2_cleanup(parked_call_type);
+	STASIS_MESSAGE_TYPE_CLEANUP(ast_parked_call_type);
 	ao2_cleanup(parking_topic);
-	parked_call_type = NULL;
 	parking_topic = NULL;
 }
 
@@ -65,11 +64,6 @@ struct stasis_topic *ast_parking_topic(void)
 	return parking_topic;
 }
 
-struct stasis_message_type *ast_parked_call_type(void)
-{
-	return parked_call_type;
-}
-
 /*! \brief Destructor for parked_call_payload objects */
 static void parked_call_payload_destructor(void *obj)
 {
diff --git a/main/stasis_channels.c b/main/stasis_channels.c
index 65e9f917d..8327384d7 100644
--- a/main/stasis_channels.c
+++ b/main/stasis_channels.c
@@ -36,29 +36,24 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/astobj2.h"
 #include "asterisk/stasis_channels.h"
 
-#define NUM_MULTI_CHANNEL_BLOB_BUCKETS 7
+/*** DOCUMENTATION
+	<managerEvent language="en_US" name="VarSet">
+		<managerEventInstance class="EVENT_FLAG_DIALPLAN">
+			<synopsis>Raised when a variable is set to a particular value.</synopsis>
+			<syntax>
+				<xi:include xpointer="xpointer(/docs/managerEvent[@name='Newchannel']/managerEventInstance/syntax/parameter)" />
+				<parameter name="Variable">
+					<para>The variable being set.</para>
+				</parameter>
+				<parameter name="Value">
+					<para>The new value of the variable.</para>
+				</parameter>
+			</syntax>
+		</managerEventInstance>
+	</managerEvent>
+***/
 
-/*!
- * @{ \brief Define channel message types.
- */
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_snapshot_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_dial_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_varset_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_user_event_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_hangup_request_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_dtmf_begin_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_dtmf_end_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_hold_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_unhold_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_chanspy_start_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_chanspy_stop_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_fax_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_hangup_handler_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_moh_start_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_moh_stop_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_monitor_start_type);
-STASIS_MESSAGE_TYPE_DEFN(ast_channel_monitor_stop_type);
-/*! @} */
+#define NUM_MULTI_CHANNEL_BLOB_BUCKETS 7
 
 /*! \brief Topic for all channels */
 struct stasis_topic *channel_topic_all;
@@ -540,6 +535,36 @@ void ast_channel_publish_varset(struct ast_channel *chan, const char *name, cons
 	ast_channel_publish_blob(chan, ast_channel_varset_type(), blob);
 }
 
+static struct ast_manager_event_blob *varset_to_ami(struct stasis_message *msg)
+{
+	RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);
+	struct ast_channel_blob *obj = stasis_message_data(msg);
+	const char *variable =
+		ast_json_string_get(ast_json_object_get(obj->blob, "variable"));
+	const char *value =
+		ast_json_string_get(ast_json_object_get(obj->blob, "value"));
+
+	if (obj->snapshot) {
+		channel_event_string =
+			ast_manager_build_channel_state_string(obj->snapshot);
+	} else {
+		channel_event_string = ast_str_create(35);
+		ast_str_set(&channel_event_string, 0,
+			    "Channel: none\r\n"
+			    "Uniqueid: none\r\n");
+	}
+
+	if (!channel_event_string) {
+		return NULL;
+	}
+
+	return ast_manager_event_blob_create(EVENT_FLAG_DIALPLAN, "VarSet",
+		"%s"
+		"Variable: %s\r\n"
+		"Value: %s\r\n",
+		ast_str_buffer(channel_event_string), variable, value);
+}
+
 void ast_publish_channel_state(struct ast_channel *chan)
 {
 	RAII_VAR(struct ast_channel_snapshot *, snapshot, NULL, ao2_cleanup);
@@ -626,6 +651,31 @@ int ast_channel_snapshot_caller_id_equal(
 		strcmp(old_snapshot->caller_name, new_snapshot->caller_name) == 0;
 }
 
+/*!
+ * @{ \brief Define channel message types.
+ */
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_snapshot_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_dial_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_varset_type,
+	.to_ami = varset_to_ami,
+	);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_user_event_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_hangup_request_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_dtmf_begin_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_dtmf_end_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_hold_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_unhold_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_chanspy_start_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_chanspy_stop_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_fax_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_hangup_handler_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_moh_start_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_moh_stop_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_monitor_start_type);
+STASIS_MESSAGE_TYPE_DEFN(ast_channel_monitor_stop_type);
+
+/*! @} */
+
 static void stasis_channels_cleanup(void)
 {
 	channel_topic_all_cached = stasis_caching_unsubscribe_and_join(channel_topic_all_cached);
diff --git a/main/stasis_message.c b/main/stasis_message.c
index 8d2373f4d..b25d1f25a 100644
--- a/main/stasis_message.c
+++ b/main/stasis_message.c
@@ -37,9 +37,12 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 
 /*! \internal */
 struct stasis_message_type {
+	struct stasis_message_vtable *vtable;
 	char *name;
 };
 
+static struct stasis_message_vtable null_vtable = {};
+
 static void message_type_dtor(void *obj)
 {
 	struct stasis_message_type *type = obj;
@@ -47,7 +50,8 @@ static void message_type_dtor(void *obj)
 	type->name = NULL;
 }
 
-struct stasis_message_type *stasis_message_type_create(const char *name)
+struct stasis_message_type *stasis_message_type_create(const char *name,
+	struct stasis_message_vtable *vtable)
 {
 	RAII_VAR(struct stasis_message_type *, type, NULL, ao2_cleanup);
 
@@ -55,11 +59,16 @@ struct stasis_message_type *stasis_message_type_create(const char *name)
 	if (!type) {
 		return NULL;
 	}
+	if (!vtable) {
+		/* Null object pattern, FTW! */
+		vtable = &null_vtable;
+	}
 
 	type->name = ast_strdup(name);
 	if (!type->name) {
 		return NULL;
 	}
+	type->vtable = vtable;
 
 	ao2_ref(type, +1);
 	return type;
@@ -133,3 +142,26 @@ const struct timeval *stasis_message_timestamp(const struct stasis_message *msg)
 	}
 	return &msg->timestamp;
 }
+
+#define INVOKE_VIRTUAL(fn, ...)				\
+	({						\
+		if (msg == NULL) {			\
+			return NULL;			\
+		}					\
+		ast_assert(msg->type != NULL);		\
+		ast_assert(msg->type->vtable != NULL);	\
+		if (msg->type->vtable->fn == NULL) {	\
+			return NULL;			\
+		}					\
+		msg->type->vtable->fn(__VA_ARGS__);	\
+	})
+
+struct ast_manager_event_blob *stasis_message_to_ami(struct stasis_message *msg)
+{
+	return INVOKE_VIRTUAL(to_ami, msg);
+}
+
+struct ast_json *stasis_message_to_json(struct stasis_message *msg)
+{
+	return INVOKE_VIRTUAL(to_json, msg);
+}