new driver design, part II

git-svn-id: svn+ssh://jackaudio.org/trunk/jack@367 0c269be4-1314-0410-8aa9-9f06e86f4224

jack/driver.h

@@ -65,6 +65,7 @@ typedef jack_nframes_t (*JackDriverWaitFunction)(struct _jack_driver *, int fd,
      3) engine starts driver
      4) while (1) {
            engine->wait ();
+	   engine->audio_cycle ();
         }
      5) engine stops driver
      6) engine detaches from driver
@@ -135,10 +136,30 @@ typedef jack_nframes_t (*JackDriverWaitFunction)(struct _jack_driver *, int fd,
 
     JackDriverWaitFunction wait;
 
+/* the JACK engine will call this to ask the driver to move
+   data from its inputs to its output port buffers. it should
+   return 0 to indicate successful completion, negative otherwise. 
+ 
+   this function will always be called after the wait function (above).
+*/
+
     JackDriverReadFunction read;
 
+/* the JACK engine will call this to ask the driver to move
+   data from its input port buffers to its outputs. it should
+   return 0 to indicate successful completion, negative otherwise. 
+ 
+   this function will always be called after the read function (above).
+*/
     JackDriverWriteFunction write;
 
+/* the JACK engine will call this after the wait function (above) has
+   been called, but for some reason the engine is unable to execute
+   a full "cycle". the driver should do whatever is necessary to
+   keep itself running correctly, but cannot reference ports
+   or other JACK data structures in any way.
+*/
+
     JackDriverNullCycleFunction null_cycle;
     
 /* the engine will call this when it plans to stop calling the `wait'

jackd/engine.c

@@ -2069,7 +2069,7 @@ jack_engine_wait (jack_engine_t *engine, jack_nframes_t* nframes)
 }
 
 static int
-jack_audio_cycle (jack_engine_t *engine, jack_nframes_t nframes)
+jack_run_cycle (jack_engine_t *engine, jack_nframes_t nframes)
 {
 	int ret;
 	jack_driver_t* driver = engine->driver;
@@ -2137,8 +2137,8 @@ jack_main_thread (void *arg)
 			
 		} else if (wait_status == 0) {
 			
-			if (jack_audio_cycle (engine, nframes)) {
-				jack_error ("audio cycle failure, exiting");
+			if (jack_run_cycle (engine, nframes)) {
+				jack_error ("cycle execution failure, exiting");
 				break;
 			}