set up property change notification structures and calls

include/internal.h

@@ -59,6 +59,7 @@ extern void jack_info (const char *fmt, ...);
 #include <jack/transport.h>
 #include <jack/session.h>
 #include <jack/thread.h>
+#include <jack/metadata.h>
 
 #include "port.h"
 
@@ -221,7 +222,8 @@ typedef enum  {
   ClientRegistered,
   ClientUnregistered,
   SaveSession,
-  LatencyCallback
+  LatencyCallback,
+  PropertyCallback
 } JackEventType;
 
 const char* jack_event_type_name (JackEventType);
@@ -233,12 +235,17 @@ typedef struct {
         char name[JACK_PORT_NAME_SIZE];    
 	jack_port_id_t port_id;
 	jack_port_id_t self_id;
+        jack_uuid_t    property_owner;            
     } x;
     union {
 	uint32_t n;
 	jack_port_type_id_t ptid;
 	jack_port_id_t other_id;
+        uint32_t key_size; /* key data will follow the event structure */
     } y;
+    union {        
+            jack_property_change_t property_change;
+    } z;
 } POST_PACKED_STRUCTURE jack_event_t;
 
 typedef enum {
@@ -301,6 +308,7 @@ typedef volatile struct {
     volatile uint8_t	thread_cb_cbset;
     volatile uint8_t	session_cbset;
     volatile uint8_t	latency_cbset;
+    volatile uint8_t	property_cbset;
 
 } POST_PACKED_STRUCTURE jack_client_control_t;
 

jackd/clientengine.c

@@ -609,6 +609,7 @@ jack_setup_client_control (jack_engine_t *engine, int fd, ClientType type, const
 	client->control->client_register_cbset = FALSE;
 	client->control->thread_cb_cbset = FALSE;
 	client->control->session_cbset = FALSE;
+	client->control->property_cbset = FALSE;
 
 #if 0
 	if (type != ClientExternal) {

libjack/local.h

@@ -77,6 +77,8 @@ struct _jack_client {
     void *session_cb_arg;
     JackLatencyCallback latency_cb;	
     void *latency_cb_arg;
+    JackPropertyChangeCallback property_cb;	
+    void *property_cb_arg;
 
     /* external clients: set by libjack
      * internal clients: set by engine */

libjack/metadata.c

@@ -24,6 +24,7 @@
 #include <jack/uuid.h>
 
 #include "internal.h"
+#include "local.h"
 
 static DB* db = NULL;
 
@@ -374,11 +375,18 @@ jack_get_all_descriptions (jack_description_t** descs)
         return 0;
 }
 
-int jack_set_property_change_callback (jack_client_t* client,
-                                       JackPropertyChangeCallback callback,
-                                       void *arg)
+int 
+jack_set_property_change_callback (jack_client_t *client,
+                                   JackPropertyChangeCallback callback, void *arg)
 {
-        return 0;
+	if (client->control->active) {
+		jack_error ("You cannot set callbacks on an active client.");
+		return -1;
+	}
+	client->property_cb = callback;
+	client->property_cb_arg = arg;
+	client->control->property_cbset = (callback != NULL);
+	return 0;
 }
 
 int