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, 135 insertions, 0 deletions

diff --git a/main/stasis_message.c b/main/stasis_message.c
new file mode 100644
index 000000000..8d397b935
--- /dev/null
+++ b/main/stasis_message.c
@@ -0,0 +1,135 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ *
+ * \brief Stasis Message API.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+/*** MODULEINFO
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/astobj2.h"
+#include "asterisk/stasis.h"
+#include "asterisk/utils.h"
+
+/*! \private */
+struct stasis_message_type {
+	char *name;
+};
+
+static void message_type_dtor(void *obj)
+{
+	struct stasis_message_type *type = obj;
+	ast_free(type->name);
+	type->name = NULL;
+}
+
+struct stasis_message_type *stasis_message_type_create(const char *name)
+{
+	RAII_VAR(struct stasis_message_type *, type, NULL, ao2_cleanup);
+
+	type = ao2_alloc(sizeof(*type), message_type_dtor);
+	if (!type) {
+		return NULL;
+	}
+
+	type->name = ast_strdup(name);
+	if (!type->name) {
+		return NULL;
+	}
+
+	ao2_ref(type, +1);
+	return type;
+}
+
+const char *stasis_message_type_name(const struct stasis_message_type *type)
+{
+	return type->name;
+}
+
+/*! \private */
+struct stasis_message {
+	/*! Time the message was created */
+	struct timeval timestamp;
+	/*! Type of the message */
+	struct stasis_message_type *type;
+	/*! Message content */
+	void *data;
+};
+
+static void stasis_message_dtor(void *obj)
+{
+	struct stasis_message *message = obj;
+	ao2_cleanup(message->type);
+	ao2_cleanup(message->data);
+}
+
+struct stasis_message *stasis_message_create(struct stasis_message_type *type, void *data)
+{
+	RAII_VAR(struct stasis_message *, message, NULL, ao2_cleanup);
+
+	if (type == NULL || data == NULL) {
+		return NULL;
+	}
+
+	message = ao2_alloc(sizeof(*message), stasis_message_dtor);
+	if (message == NULL) {
+		return NULL;
+	}
+
+	message->timestamp = ast_tvnow();
+	ao2_ref(type, +1);
+	message->type = type;
+	ao2_ref(data, +1);
+	message->data = data;
+
+	ao2_ref(message, +1);
+	return message;
+}
+
+struct stasis_message_type *stasis_message_type(const struct stasis_message *msg)
+{
+	if (msg == NULL) {
+		return NULL;
+	}
+	return msg->type;
+}
+
+void *stasis_message_data(const struct stasis_message *msg)
+{
+	if (msg == NULL) {
+		return NULL;
+	}
+	return msg->data;
+}
+
+const struct timeval *stasis_message_timestamp(const struct stasis_message *msg)
+{
+	if (msg == NULL) {
+		return NULL;
+	}
+	return &msg->timestamp;
+}