Immediate-event/out-of-band injection update & tweak clearing buffers

Immediate events are used for MIDI-Panic and to inject GUI generated
events e.g. patch-changes, note-events from the track-header
(scroomer-keyboard) and patch-change audition.

Current behavior:

- snapshot copy immediate events from ringbuffer into a buffer at
  the beginning of each the cycle.
- Inject immediate events into input-buffer directly after reading the input
- process "normally"
- pass immediate event-buffer to disk-writer, so it can skip them
  (don't write immediate events to disk)
- if the Route is not monitoring input: clear buffer before disk-reader
  and re-inject (original) immediate events after the disk-reader
- immediate events process normally and are also sent to outputs.

1 files changed, 3 insertions, 1 deletions

diff --git a/libs/ardour/ardour/route.h b/libs/ardour/ardour/route.h
index 1437fd79ed..830ef4bab3 100644
--- a/libs/ardour/ardour/route.h
+++ b/libs/ardour/ardour/route.h
@@ -597,7 +597,9 @@ protected:
 
 	virtual int no_roll_unlocked (pframes_t nframes, samplepos_t start_sample, samplepos_t end_sample, bool session_state_changing);
 
-	virtual void write_out_of_band_data (BufferSet& /* bufs */, samplepos_t /* start_sample */, samplepos_t /* end_sample */, samplecnt_t /* nframes */) {}
+	virtual void snapshot_out_of_band_data (samplecnt_t /* nframes */) {}
+	virtual void write_out_of_band_data (BufferSet&, samplecnt_t /* nframes */) const {}
+	virtual void update_controls (BufferSet const&) {}
 
 	void process_output_buffers (BufferSet& bufs,
 	                             samplepos_t start_sample, samplepos_t end_sample,