Merge a set of device state improvements from team/russell/events.

The way a device state change propagates is kind of silly, in my opinion.  A
device state provider calls a function that indicates that the state of a
device has changed.  Then, another thread goes back and calls a callback for
the device state provider to find out what the new state is before it can go
send it off to whoever cares.

I have changed it so that you can include the state that the device has changed
to in the first function call from the device state provider.  This removes the
need to have to call the callback, which locks up critical containers to go find
out what the state changed to.

This change set changes the "simple" device state providers to use the new method.
This includes parking, meetme, and SLA.

I have also mostly converted chan_agent in my branch, but still have some more
things to think through before presenting the plan for converting channel drivers
to ensure all of the right events get generated ...


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@79027 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 92 insertions, 18 deletions

diff --git a/main/devicestate.c b/main/devicestate.c
index 05a775227..aef21f70a 100644
--- a/main/devicestate.c
+++ b/main/devicestate.c
@@ -25,6 +25,7 @@
  *
  *	\arg \ref AstExtState
  */
+
 /*! \page AstExtState Extension and device states in Asterisk
  *
  *	Asterisk has an internal system that reports states
@@ -166,6 +167,17 @@ static pthread_t change_thread = AST_PTHREADT_NULL;
 /*! \brief Flag for the queue */
 static ast_cond_t change_pending;
 
+/*! \brief Whether or not to cache this device state value */
+enum devstate_cache {
+	/*! Cache this value as it is coming from a device state provider which is
+	 *  pushing up state change events to us as they happen */
+	CACHE_ON,
+	/*! Don't cache this result, since it was pulled from the device state provider.
+	 *  We only want to cache results from device state providers that are being nice
+	 *  and pushing state change events up to us as they happen. */
+	CACHE_OFF,
+};
+
 /* Forward declarations */
 static int getproviderstate(const char *provider, const char *address);
 
@@ -261,18 +273,42 @@ enum ast_device_state ast_parse_device_state(const char *device)
 	return res;
 }
 
+static enum ast_device_state devstate_cached(const char *device)
+{
+	enum ast_device_state res = AST_DEVICE_UNKNOWN;
+	struct ast_event *event;
+
+	event = ast_event_get_cached(AST_EVENT_DEVICE_STATE,
+		AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
+		AST_EVENT_IE_END);
+
+	if (!event)
+		return res;
+
+	res = ast_event_get_ie_uint(event, AST_EVENT_IE_STATE);
+
+	ast_event_destroy(event);
+
+	return res;
+}
+
 /*! \brief Check device state through channel specific function or generic function */
 enum ast_device_state ast_device_state(const char *device)
 {
 	char *buf;
 	char *number;
 	const struct ast_channel_tech *chan_tech;
-	enum ast_device_state res = AST_DEVICE_UNKNOWN;
+	enum ast_device_state res;
 	/*! \brief Channel driver that provides device state */
 	char *tech;
 	/*! \brief Another provider of device state */
 	char *provider = NULL;
-	
+
+	/* If the last known state is cached, just return that */
+	res = devstate_cached(device);
+	if (res != AST_DEVICE_UNKNOWN)
+		return res;
+
 	buf = ast_strdupa(device);
 	tech = strsep(&buf, "/");
 	if (!(number = buf)) {
@@ -368,17 +404,10 @@ static int getproviderstate(const char *provider, const char *address)
 	return res;
 }
 
-/*! \brief Notify callback watchers of change, and notify PBX core for hint updates
-	Normally executed within a separate thread
-*/
-static void do_state_change(const char *device)
+static void devstate_event(const char *device, enum ast_device_state state, enum devstate_cache cache)
 {
-	enum ast_device_state state;
 	struct ast_event *event;
 
-	state = ast_device_state(device);
-	ast_debug(3, "Changing state for %s - state %d (%s)\n", device, state, devstate2str(state));
-
 	if (!(event = ast_event_new(AST_EVENT_DEVICE_STATE,
 			AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR, device,
 			AST_EVENT_IE_STATE, AST_EVENT_IE_PLTYPE_UINT, state,
@@ -386,12 +415,31 @@ static void do_state_change(const char *device)
 		return;
 	}
 
-	ast_event_queue_and_cache(event,
-		AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR,
-		AST_EVENT_IE_END);
+	if (cache == CACHE_ON) {
+		/* Cache this event, replacing an event in the cache with the same
+		 * device name if it exists. */
+		ast_event_queue_and_cache(event,
+			AST_EVENT_IE_DEVICE, AST_EVENT_IE_PLTYPE_STR,
+			AST_EVENT_IE_END);
+	} else {
+		ast_event_queue(event);
+	}
 }
 
-static int __ast_device_state_changed_literal(char *buf)
+/*! Called by the state change thread to find out what the state is, and then
+ *  to queue up the state change event */
+static void do_state_change(const char *device)
+{
+	enum ast_device_state state;
+
+	state = ast_device_state(device);
+
+	ast_debug(3, "Changing state for %s - state %d (%s)\n", device, state, devstate2str(state));
+
+	devstate_event(device, state, CACHE_OFF);
+}
+
+static int __ast_devstate_changed_literal(enum ast_device_state state, char *buf)
 {
 	char *device;
 	struct state_change *change;
@@ -404,8 +452,10 @@ static int __ast_device_state_changed_literal(char *buf)
 	tmp = strrchr(device, '-');
 	if (tmp)
 		*tmp = '\0';
-	
-	if (change_thread == AST_PTHREADT_NULL || !(change = ast_calloc(1, sizeof(*change) + strlen(device)))) {
+
+	if (state != AST_DEVICE_UNKNOWN) {
+		devstate_event(device, state, CACHE_ON);
+	} else if (change_thread == AST_PTHREADT_NULL || !(change = ast_calloc(1, sizeof(*change) + strlen(device)))) {
 		/* we could not allocate a change struct, or */
 		/* there is no background thread, so process the change now */
 		do_state_change(device);
@@ -421,11 +471,34 @@ static int __ast_device_state_changed_literal(char *buf)
 	return 1;
 }
 
+int ast_devstate_changed_literal(enum ast_device_state state, const char *dev)
+{
+	char *buf;
+
+	buf = ast_strdupa(dev);
+
+	return __ast_devstate_changed_literal(state, buf);
+}
+
 int ast_device_state_changed_literal(const char *dev)
 {
 	char *buf;
+
 	buf = ast_strdupa(dev);
-	return __ast_device_state_changed_literal(buf);
+
+	return __ast_devstate_changed_literal(AST_DEVICE_UNKNOWN, buf);
+}
+
+int ast_devstate_changed(enum ast_device_state state, const char *fmt, ...) 
+{
+	char buf[AST_MAX_EXTENSION];
+	va_list ap;
+
+	va_start(ap, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, ap);
+	va_end(ap);
+
+	return __ast_devstate_changed_literal(state, buf);
 }
 
 /*! \brief Accept change notification, add it to change queue */
@@ -437,7 +510,8 @@ int ast_device_state_changed(const char *fmt, ...)
 	va_start(ap, fmt);
 	vsnprintf(buf, sizeof(buf), fmt, ap);
 	va_end(ap);
-	return __ast_device_state_changed_literal(buf);
+
+	return __ast_devstate_changed_literal(AST_DEVICE_UNKNOWN, buf);
 }
 
 /*! \brief Go through the dev state change queue and update changes in the dev state thread */