Maintain correct tracker state on MIDI overwrite.

This is a little hard-edged in that edits while rolling will prematurely chop
off any playing notes, but at least the state of things actually reflects
reality.  More sophisticated solution hopefully to come...

libs/ardour/ardour/midi_playlist.h

@@ -63,7 +63,15 @@ public:
 
 	std::set<Evoral::Parameter> contained_automation();
 
-	void clear_note_trackers ();
+	/** Clear all note trackers. */
+	void reset_note_trackers ();
+
+	/** Resolve all pending notes and clear all note trackers.
+	 *
+	 * @param dst Sink to write note offs to.
+	 * @param time Time stamp of all written note offs.
+	 */
+	void resolve_note_trackers (Evoral::EventSink<framepos_t>& dst, framepos_t time);
 
 protected:
 

libs/ardour/ardour/midi_ring_buffer.h

@@ -54,7 +54,7 @@ public:
 	void flush (framepos_t start, framepos_t end);
 
 	void reset_tracker ();
-	void loop_resolve (MidiBuffer& dst, framepos_t);
+	void resolve_tracker (MidiBuffer& dst, framepos_t);
 
 private:
 	MidiStateTracker _tracker;

libs/ardour/midi_diskstream.cc

@@ -606,12 +606,20 @@ MidiDiskstream::set_pending_overwrite (bool yn)
 int
 MidiDiskstream::overwrite_existing_buffers ()
 {
-	/* This is safe as long as the butler thread is suspended, which it should be */
+	/* Clear the playback buffer contents.  This is safe as long as the butler
+	   thread is suspended, which it should be. */
 	_playback_buf->reset ();
+	_playback_buf->reset_tracker ();
 
 	g_atomic_int_set (&_frames_read_from_ringbuffer, 0);
 	g_atomic_int_set (&_frames_written_to_ringbuffer, 0);
 
+	/* Resolve all currently active notes in the playlist.  This is more
+	   aggressive than it needs to be: ideally we would only resolve what is
+	   absolutely necessary, but this seems difficult and/or impossible without
+	   having the old data or knowing what change caused the overwrite. */
+	midi_playlist()->resolve_note_trackers (*_playback_buf, overwrite_frame);
+
 	read (overwrite_frame, disk_io_chunk_frames, false);
 	file_frame = overwrite_frame; // it was adjusted by ::read()
 	overwrite_queued = false;
@@ -1398,7 +1406,7 @@ MidiDiskstream::get_playback (MidiBuffer& dst, framecnt_t nframes)
 			   beyond the loop end.
 			*/
 
-			_playback_buf->loop_resolve (dst, 0);
+			_playback_buf->resolve_tracker (dst, 0);
 		}
 
 		if (loc->end() >= effective_start && loc->end() < effective_start + nframes) {
@@ -1489,7 +1497,7 @@ MidiDiskstream::reset_tracker ()
 	boost::shared_ptr<MidiPlaylist> mp (midi_playlist());
 
 	if (mp) {
-		mp->clear_note_trackers ();
+		mp->reset_note_trackers ();
 	}
 }
 

libs/ardour/midi_playlist.cc

@@ -288,14 +288,27 @@ MidiPlaylist::read (Evoral::EventSink<framepos_t>& dst, framepos_t start, framec
 }
 
 void
-MidiPlaylist::clear_note_trackers ()
+MidiPlaylist::reset_note_trackers ()
 {
 	Playlist::RegionWriteLock rl (this, false);
 
 	for (NoteTrackers::iterator n = _note_trackers.begin(); n != _note_trackers.end(); ++n) {
 		delete n->second;
 	}
-	DEBUG_TRACE (DEBUG::MidiTrackers, string_compose ("%1 clears all note trackers\n", name()));
+	DEBUG_TRACE (DEBUG::MidiTrackers, string_compose ("%1 reset all note trackers\n", name()));
+	_note_trackers.clear ();
+}
+
+void
+MidiPlaylist::resolve_note_trackers (Evoral::EventSink<framepos_t>& dst, framepos_t time)
+{
+	Playlist::RegionWriteLock rl (this, false);
+
+	for (NoteTrackers::iterator n = _note_trackers.begin(); n != _note_trackers.end(); ++n) {
+		n->second->resolve_notes(dst, time);
+		delete n->second;
+	}
+	DEBUG_TRACE (DEBUG::MidiTrackers, string_compose ("%1 resolve all note trackers\n", name()));
 	_note_trackers.clear ();
 }
 

libs/ardour/midi_region.cc

@@ -414,6 +414,12 @@ MidiRegion::model_changed ()
 void
 MidiRegion::model_contents_changed ()
 {
+	{
+		/* Invalidate source iterator to force reading new contents even if the
+		   calls to read progress linearly. */
+		Glib::Threads::Mutex::Lock lm (midi_source(0)->mutex());
+		midi_source(0)->invalidate (lm);
+	}
 	send_change (PropertyChange (Properties::midi_data));
 }
 

libs/ardour/midi_ring_buffer.cc

@@ -241,7 +241,7 @@ MidiRingBuffer<T>::reset_tracker ()
 
 template<typename T>
 void
-MidiRingBuffer<T>::loop_resolve (MidiBuffer& dst, framepos_t t)
+MidiRingBuffer<T>::resolve_tracker (MidiBuffer& dst, framepos_t t)
 {
 	_tracker.resolve_notes (dst, t);
 }

libs/ardour/smf_source.cc

@@ -282,13 +282,8 @@ SMFSource::read_unlocked (const Lock&                    lock,
 
 		if (ev_frame_time < start + duration) {
 			destination.write (ev_frame_time, ev_type, ev_size, ev_buffer);
-
 			if (tracker) {
-				if (ev_buffer[0] & MIDI_CMD_NOTE_ON) {
-					tracker->add (ev_buffer[1], ev_buffer[0] & 0xf);
-				} else if (ev_buffer[0] & MIDI_CMD_NOTE_OFF) {
-					tracker->remove (ev_buffer[1], ev_buffer[0] & 0xf);
-				}
+				tracker->track(ev_buffer);
 			}
 		} else {
 			break;