Cont'd work on fixing export ranges

This picks up where cfd95340b1 left off.

The goal is to ensure that the butler has completed all
PostTransportStop related tasks and won't meddle with transport
after exporting has started.

Previously this could happen, because realtime_stop() queues
PostTransportStop and the butler is sommoned after every
export process cycle.

Since  61e7f3176bf the butler keeps calling non_realtime_stop()
every time it is woken up, until TFSM comes around and unsets the
flag in the process callback.

1 files changed, 16 insertions, 4 deletions

diff --git a/libs/ardour/session_export.cc b/libs/ardour/session_export.cc
index 79e0b5a51b..0c8811a969 100644
--- a/libs/ardour/session_export.cc
+++ b/libs/ardour/session_export.cc
@@ -110,9 +110,11 @@ Session::pre_export ()
 int
 Session::start_audio_export (samplepos_t position, bool realtime, bool region_export)
 {
+	assert (!engine().in_process_thread ());
+
 	if (!_exporting) {
 		pre_export ();
-	} else {
+	} else if (_transport_speed != 0) {
 		realtime_stop (true, true);
 	}
 
@@ -132,13 +134,21 @@ Session::start_audio_export (samplepos_t position, bool realtime, bool region_ex
 		_export_preroll = 1;
 	}
 
+	/* realtime_stop will have queued butler work (and TSFM),
+	 * but the butler may not run immediately, so well have
+	 * to wait for it to wake up and call
+	 * non_realtime_stop ().
+	 */
+	do {
+		Glib::usleep (engine().usecs_per_cycle ());
+		_butler->schedule_transport_work ();
+	} while (0 != post_transport_work ());
+
 	/* We're about to call Track::seek, so the butler must have finished everything
 	   up otherwise it could be doing do_refill in its thread while we are doing
 	   it here.
 	*/
 
-	Glib::usleep (engine().usecs_per_cycle ());
-	_butler->schedule_transport_work ();
 	_butler->wait_until_finished ();
 
 	/* get everyone to the right position */
@@ -241,7 +251,8 @@ Session::process_export (pframes_t nframes)
 
 		if (ProcessExport (nframes).value_or (0) > 0) {
 			/* last cycle completed */
-			flush_all_inserts ();
+			assert (_export_rolling);
+			stop_audio_export ();
 		}
 
 	} catch (std::exception & e) {
@@ -361,6 +372,7 @@ Session::stop_audio_export ()
 	*/
 
 	realtime_stop (true, true);
+	flush_all_inserts ();
 	_export_rolling = false;
 	_butler->schedule_transport_work ();