don't loose a redraw.

This more or less obsoletes the DisplaySuspender.
While RAII is nice, the DisplaySuspender cannot be
used from outside gtk2_ardour eg Mute/Solo signals
notifications from libardour (which don't originate
from the GUI).

The DisplaySuspender is still useful, because it
explicitly disables re-display and forces a single
expose at the end.

gtk2_ardour/editor_routes.cc

@@ -70,10 +70,10 @@ EditorRoutes::EditorRoutes (Editor* e)
 	: EditorComponent (e)
         , _ignore_reorder (false)
         , _no_redisplay (false)
-        , _redisplaying (false)
-        , _redisplay_2 (false)
         , _adding_routes (false)
         , _route_deletion_in_progress (false)
+        , _redisplay_active (0)
+        , _queue_tv_update (0)
         , _menu (0)
         , old_focus (0)
         , selection_countdown (0)
@@ -495,24 +495,14 @@ EditorRoutes::show_menu ()
 }
 
 void
-EditorRoutes::redisplay ()
+EditorRoutes::redisplay_real ()
 {
-	if (_redisplaying) {
-		_redisplay_2 = true;
-		return;
-	}
-	if (_no_redisplay || !_session || _session->deletion_in_progress()) {
-		return;
-	}
-	_redisplay_2 = false;
-	_redisplaying = true; // tv->show_at() below causes recursive redisplay via handle_gui_changes()
-
 	TreeModel::Children rows = _model->children();
 	TreeModel::Children::iterator i;
 	uint32_t position;
 
 	/* n will be the count of tracks plus children (updated by TimeAxisView::show_at),
-	   so we will use that to know where to put things.
+	 * so we will use that to know where to put things.
 	 */
 	int n;
 
@@ -538,8 +528,8 @@ EditorRoutes::redisplay ()
 	}
 
 	/* whenever we go idle, update the track view list to reflect the new order.
-	   we can't do this here, because we could mess up something that is traversing
+	 * we can't do this here, because we could mess up something that is traversing
-	   the track order and has caused a redisplay of the list.
+	 * the track order and has caused a redisplay of the list.
 	 */
 	Glib::signal_idle().connect (sigc::mem_fun (*_editor, &Editor::sync_track_view_list_and_routes));
 
@@ -549,14 +539,32 @@ EditorRoutes::redisplay ()
 
 	if ((_editor->vertical_adjustment.get_value() + _editor->_visible_canvas_height) > _editor->vertical_adjustment.get_upper()) {
 		/*
-		   We're increasing the size of the canvas while the bottom is visible.
+		 * We're increasing the size of the canvas while the bottom is visible.
-		   We scroll down to keep in step with the controls layout.
+		 * We scroll down to keep in step with the controls layout.
 		 */
 		_editor->vertical_adjustment.set_value (_editor->_full_canvas_height - _editor->_visible_canvas_height);
 	}
-	_redisplaying = false;
+}
-	if (_redisplay_2) {
+
-		redisplay();
+void
+EditorRoutes::redisplay ()
+{
+	if (_no_redisplay || !_session || _session->deletion_in_progress()) {
+		return;
+	}
+
+	// model deprecated g_atomic_int_exchange_and_add(, 1)
+	g_atomic_int_inc(&_redisplay_active);
+	if (!g_atomic_int_compare_and_exchange (&_redisplay_active, 1, 1)) {
+		printf ("SKIP redisplay\n");
+		return;
+	}
+
+	redisplay_real ();
+
+	while (!g_atomic_int_compare_and_exchange (&_redisplay_active, 1, 0)) {
+		g_atomic_pointer_set(&_redisplay_active, 1);
+		redisplay_real ();
 	}
 }
 
@@ -792,10 +800,9 @@ EditorRoutes::route_property_changed (const PropertyChange& what_changed, boost:
 void
 EditorRoutes::update_active_display ()
 {
-	if (_queue_mute_rec_solo_etc == 0) {
+	if (g_atomic_int_compare_and_exchange (&_queue_tv_update, 0, 1)) {
 		Glib::signal_idle().connect (sigc::mem_fun (*this, &EditorRoutes::idle_update_mute_rec_solo_etc));
 	}
-	_queue_mute_rec_solo_etc |= 16;
 }
 
 void
@@ -1570,39 +1577,26 @@ EditorRoutes::update_input_active_display ()
 void
 EditorRoutes::update_rec_display ()
 {
-	if (_queue_mute_rec_solo_etc == 0) {
+	if (g_atomic_int_compare_and_exchange (&_queue_tv_update, 0, 1)) {
 		Glib::signal_idle().connect (sigc::mem_fun (*this, &EditorRoutes::idle_update_mute_rec_solo_etc));
 	}
-	_queue_mute_rec_solo_etc |= 32;
 }
 
 bool
 EditorRoutes::idle_update_mute_rec_solo_etc()
 {
-	const int what = _queue_mute_rec_solo_etc;
+	g_atomic_int_set (&_queue_tv_update, 0);
-	_queue_mute_rec_solo_etc = 0;
 	TreeModel::Children rows = _model->children();
 	TreeModel::Children::iterator i;
 
 	for (i = rows.begin(); i != rows.end(); ++i) {
 		boost::shared_ptr<Route> route = (*i)[_columns.route];
-		if (what & 1) {
 		(*i)[_columns.mute_state] = RouteUI::mute_active_state (_session, route);
-		}
-		if (what & 2) {
 		(*i)[_columns.solo_state] = RouteUI::solo_active_state (route);
-		}
-		if (what & 4) {
 		(*i)[_columns.solo_isolate_state] = RouteUI::solo_isolate_active_state (route) ? 1 : 0;
-		}
-		if (what & 8) {
 		(*i)[_columns.solo_safe_state] = RouteUI::solo_safe_active_state (route) ? 1 : 0;
-		}
-		if (what & 16) {
 		(*i)[_columns.active] = route->active ();
-		}
+		{
-		if (what & 32) { // rec
-
 			if (boost::dynamic_pointer_cast<Track> (route)) {
 				boost::shared_ptr<MidiTrack> mt = boost::dynamic_pointer_cast<MidiTrack> (route);
 
@@ -1629,37 +1623,33 @@ EditorRoutes::idle_update_mute_rec_solo_etc()
 void
 EditorRoutes::update_mute_display ()
 {
-	if (_queue_mute_rec_solo_etc == 0) {
+	if (g_atomic_int_compare_and_exchange (&_queue_tv_update, 0, 1)) {
 		Glib::signal_idle().connect (sigc::mem_fun (*this, &EditorRoutes::idle_update_mute_rec_solo_etc));
 	}
-	_queue_mute_rec_solo_etc |= 1;
 }
 
 void
 EditorRoutes::update_solo_display (bool /* selfsoloed */)
 {
-	if (_queue_mute_rec_solo_etc == 0) {
+	if (g_atomic_int_compare_and_exchange (&_queue_tv_update, 0, 1)) {
 		Glib::signal_idle().connect (sigc::mem_fun (*this, &EditorRoutes::idle_update_mute_rec_solo_etc));
 	}
-	_queue_mute_rec_solo_etc |= 2;
 }
 
 void
 EditorRoutes::update_solo_isolate_display ()
 {
-	if (_queue_mute_rec_solo_etc == 0) {
+	if (g_atomic_int_compare_and_exchange (&_queue_tv_update, 0, 1)) {
 		Glib::signal_idle().connect (sigc::mem_fun (*this, &EditorRoutes::idle_update_mute_rec_solo_etc));
 	}
-	_queue_mute_rec_solo_etc |= 4;
 }
 
 void
 EditorRoutes::update_solo_safe_display ()
 {
-	if (_queue_mute_rec_solo_etc == 0) {
+	if (g_atomic_int_compare_and_exchange (&_queue_tv_update, 0, 1)) {
 		Glib::signal_idle().connect (sigc::mem_fun (*this, &EditorRoutes::idle_update_mute_rec_solo_etc));
 	}
-	_queue_mute_rec_solo_etc |= 4;
 }
 
 list<TimeAxisView*>

gtk2_ardour/editor_routes.h

@@ -60,6 +60,7 @@ public:
 
 private:
 	void initial_display ();
+	void redisplay_real ();
 	void on_input_active_changed (std::string const &);
 	void on_tv_rec_enable_changed (std::string const &);
 	void on_tv_mute_enable_toggled (std::string const &);
@@ -152,11 +153,10 @@ private:
 
 	bool _ignore_reorder;
 	bool _no_redisplay;
-	bool _redisplaying;
-	bool _redisplay_2;
 	bool _adding_routes;
 	bool _route_deletion_in_progress;
-	int  _queue_mute_rec_solo_etc;
+	volatile gint _redisplay_active;
+	volatile gint _queue_tv_update;
 
 	Gtk::Menu* _menu;
 	Gtk::Widget* old_focus;