Implement record with preroll

libs/ardour/ardour/session.h

@@ -998,6 +998,10 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 
 	void maybe_update_session_range (framepos_t, framepos_t);
 
+	void request_preroll_record (framepos_t);
+	framepos_t preroll_record_in () const { return _preroll_record_in; }
+	bool preroll_record_enabled () const { return _preroll_record_in >= 0; }
+
 	/* temporary hacks to allow selection to be pushed from GUI into backend.
 	   Whenever we move the selection object into libardour, these will go away.
 	 */
@@ -1915,6 +1919,9 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	Evoral::Range<framepos_t> _range_selection;
 	Evoral::Range<framepos_t> _object_selection;
 
+	void unset_preroll_record ();
+	framepos_t _preroll_record_in;
+
 	/* main outs */
 	uint32_t main_outs;
 

libs/ardour/ardour/session_event.h

@@ -47,6 +47,7 @@ public:
 		SetLoop,
 		PunchIn,
 		PunchOut,
+		RecordStart,
 		RangeStop,
 		RangeLocate,
 		Overwrite,

libs/ardour/audio_diskstream.cc

@@ -1923,7 +1923,9 @@ AudioDiskstream::get_state ()
 
 		Location* pi;
 
-		if (_session.config.get_punch_in() && ((pi = _session.locations()->auto_punch_location()) != 0)) {
+		if (_session.preroll_record_enabled ()) {
+			snprintf (buf, sizeof (buf), "%" PRId64, _session.preroll_record_in ());
+		} else if (_session.config.get_punch_in() && ((pi = _session.locations()->auto_punch_location()) != 0)) {
 			snprintf (buf, sizeof (buf), "%" PRId64, pi->start());
 		} else {
 			snprintf (buf, sizeof (buf), "%" PRId64, _session.transport_frame());

libs/ardour/midi_diskstream.cc

@@ -367,7 +367,7 @@ MidiDiskstream::process (BufferSet& bufs, framepos_t transport_frame, pframes_t
 
 	adjust_capture_position = 0;
 
-	if (nominally_recording || (re && was_recording && _session.get_record_enabled() && _session.config.get_punch_in())) {
+	if (nominally_recording || (re && was_recording && _session.get_record_enabled() && (_session.config.get_punch_in() || _session.preroll_record_enabled()))) {
 		Evoral::OverlapType ot = Evoral::coverage (first_recordable_frame, last_recordable_frame, transport_frame, transport_frame + nframes);
 		// XXX should this be transport_frame + nframes - 1 ? coverage() expects its parameter ranges to include their end points
 
@@ -1238,7 +1238,9 @@ MidiDiskstream::get_state ()
 
 		Location* pi;
 
-		if (_session.config.get_punch_in() && ((pi = _session.locations()->auto_punch_location()) != 0)) {
+		if (_session.preroll_record_enabled ()) {
+			snprintf (buf, sizeof (buf), "%" PRId64, _session.preroll_record_in ());
+		} else if (_session.config.get_punch_in() && ((pi = _session.locations()->auto_punch_location()) != 0)) {
 			snprintf (buf, sizeof (buf), "%" PRId64, pi->start());
 		} else {
 			snprintf (buf, sizeof (buf), "%" PRId64, _session.transport_frame());

libs/ardour/session.cc

@@ -304,6 +304,7 @@ Session::Session (AudioEngine &eng,
 	, _play_range (false)
 	, _range_selection (-1,-1)
 	, _object_selection (-1,-1)
+	, _preroll_record_in (-1)
 	, main_outs (0)
 	, first_file_data_format_reset (true)
 	, first_file_header_format_reset (true)
@@ -781,6 +782,7 @@ Session::destroy ()
 			case SessionEvent::Skip:
 			case SessionEvent::PunchIn:
 			case SessionEvent::PunchOut:
+			case SessionEvent::RecordStart:
 			case SessionEvent::StopOnce:
 			case SessionEvent::RangeStop:
 			case SessionEvent::RangeLocate:
@@ -1999,6 +2001,7 @@ Session::disable_record (bool rt_context, bool force)
 		if (!rt_context) {
 			remove_pending_capture_state ();
 		}
+		unset_preroll_record ();
 	}
 }
 
@@ -2036,7 +2039,7 @@ Session::maybe_enable_record (bool rt_context)
 	}
 
 	if (_transport_speed) {
-		if (!config.get_punch_in()) {
+		if (!config.get_punch_in() && !preroll_record_enabled ()) {
 			enable_record ();
 		}
 	} else {

libs/ardour/session_process.cc

@@ -1156,7 +1156,7 @@ Session::process_event (SessionEvent* ev)
 
 	case SessionEvent::PunchIn:
 		// cerr << "PunchIN at " << transport_frame() << endl;
-		if (config.get_punch_in() && record_status() == Enabled) {
+		if (config.get_punch_in() && record_status() == Enabled && !preroll_record_enabled()) {
 			enable_record ();
 		}
 		remove = false;
@@ -1165,13 +1165,21 @@ Session::process_event (SessionEvent* ev)
 
 	case SessionEvent::PunchOut:
 		// cerr << "PunchOUT at " << transport_frame() << endl;
-		if (config.get_punch_out()) {
+		if (config.get_punch_out() && !preroll_record_enabled()) {
 			step_back_from_record ();
 		}
 		remove = false;
 		del = false;
 		break;
 
+	case SessionEvent::RecordStart:
+		if (preroll_record_enabled() && record_status() == Enabled) {
+			enable_record ();
+		}
+		remove = false;
+		del = false;
+		break;
+
 	case SessionEvent::StopOnce:
 		if (!non_realtime_work_pending()) {
 			_clear_event_type (SessionEvent::StopOnce);
@@ -1271,6 +1279,9 @@ Session::compute_stop_limit () const
 		return max_framepos;
 	}
 
+	if (preroll_record_enabled ()) {
+		return max_framepos;
+	}
 
 	bool const punching_in = (config.get_punch_in () && _locations->auto_punch_location());
 	bool const punching_out = (config.get_punch_out () && _locations->auto_punch_location());

libs/ardour/session_transport.cc

@@ -161,6 +161,27 @@ Session::force_locate (framepos_t target_frame, bool with_roll)
 	queue_event (ev);
 }
 
+void
+Session::unset_preroll_record ()
+{
+	if (_preroll_record_in >= 0) {
+		remove_event (_preroll_record_in, SessionEvent::RecordStart);
+	}
+	_preroll_record_in = -1;
+}
+
+void
+Session::request_preroll_record (framepos_t rec_in)
+{
+	unset_preroll_record ();
+	_preroll_record_in = rec_in;
+	if (_preroll_record_in >= 0) {
+		replace_event (SessionEvent::RecordStart, _preroll_record_in);
+		config.set_punch_in (false);
+		config.set_punch_out (false);
+	}
+}
+
 void
 Session::request_play_loop (bool yn, bool change_transport_roll)
 {
@@ -1583,7 +1604,7 @@ Session::start_transport ()
 
 	switch (record_status()) {
 	case Enabled:
-		if (!config.get_punch_in()) {
+		if (!config.get_punch_in() && !preroll_record_enabled()) {
 			enable_record ();
 		}
 		break;

libs/ardour/track.cc

@@ -957,7 +957,7 @@ Track::monitoring_state () const
 	 * enabled and those where it is not.
 	 */
 
-	if (_session.config.get_punch_in() || _session.config.get_punch_out()) {
+	if (_session.config.get_punch_in() || _session.config.get_punch_out() || _session.preroll_record_in () >= 0) {
 		session_rec = _session.actively_recording ();
 	} else {
 		session_rec = _session.get_record_enabled();