From 4db7aa6bdc3c98e7c46745550b622bd302c3b6fb Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Sat, 15 Jan 2022 22:53:36 -0700
Subject: [PATCH] add Editor API to manage tempo map edits (at least, drags)

---
 gtk2_ardour/editor.h               |  3 +++
 gtk2_ardour/editor_tempodisplay.cc | 25 +++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 8017a9d6cc..d7cec55753 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -1847,6 +1847,9 @@ private:
 
 	void reassociate_metric_markers (Temporal::TempoMap::SharedPtr const &);
 	void reassociate_metric_marker (Temporal::TempoMap::SharedPtr const & tmap, Temporal::TempoMap::Metrics & metric, ArdourMarker& marker);
+	void begin_tempo_map_edit ();
+	void abort_tempo_map_edit ();
+	void commit_tempo_map_edit ();
 	void tempo_map_changed ();
 
 	void redisplay_grid (bool immediate_redraw);
diff --git a/gtk2_ardour/editor_tempodisplay.cc b/gtk2_ardour/editor_tempodisplay.cc
index 2a01136245..5e4f4a6d9b 100644
--- a/gtk2_ardour/editor_tempodisplay.cc
+++ b/gtk2_ardour/editor_tempodisplay.cc
@@ -626,3 +626,28 @@ Editor::real_remove_meter_marker (Temporal::MeterPoint *section)
 
 	return FALSE;
 }
+
+void
+Editor::begin_tempo_map_edit ()
+{
+	TempoMap::fetch_writable ();
+	TempoMap::SharedPtr tmap (TempoMap::use());
+	reassociate_metric_markers (tmap);
+}
+
+void
+Editor::abort_tempo_map_edit ()
+{
+	/* this drops the lock held while we have a writable copy in our per-thread pointer */
+	TempoMap::abort_update ();
+
+	TempoMap::SharedPtr tmap (TempoMap::fetch());
+	reassociate_metric_markers (tmap);
+}
+
+void
+Editor::commit_tempo_map_edit ()
+{
+	TempoMap::SharedPtr tmap (TempoMap::use());
+	TempoMap::update (tmap);
+}