From d010ef5d993f8c818b401185e10cb7aa1f854c5f Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sat, 28 Jun 2014 21:27:36 +0200
Subject: [PATCH] add Session::StateProtector

temp. disable save during batch updates, save once at
the end.
---
 libs/ardour/ardour/session.h | 22 ++++++++++++++++++++++
 libs/ardour/session.cc       |  2 ++
 libs/ardour/session_state.cc |  6 ++++++
 3 files changed, 30 insertions(+)

diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index a3f89f8355..42f5ef9b75 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -433,6 +433,23 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 
 	StateOfTheState state_of_the_state() const { return _state_of_the_state; }
 
+	class StateProtector {
+		public:
+			StateProtector (Session* s) : _session (s) {
+				g_atomic_int_inc (&s->_suspend_save);
+			}
+			~StateProtector () {
+				if (g_atomic_int_dec_and_test (&_session->_suspend_save)) {
+					while (_session->_save_queued) {
+						_session->_save_queued = false;
+						_session->save_state ("");
+					}
+				}
+			}
+		private:
+			Session * _session;
+	};
+
 	void add_route_group (RouteGroup *);
 	void remove_route_group (RouteGroup&);
 	void reorder_route_groups (std::list<RouteGroup*>);
@@ -1106,6 +1123,10 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	bool             state_was_pending;
 	StateOfTheState _state_of_the_state;
 
+	friend class    StateProtector;
+	gint            _suspend_save; /* atomic */
+	volatile bool   _save_queued;
+
 	void     auto_save();
 	int      load_options (const XMLNode&);
 	int      load_state (std::string snapshot_name);
@@ -1658,6 +1679,7 @@ class LIBARDOUR_API Session : public PBD::StatefulDestructible, public PBD::Scop
 	static int get_session_info_from_path (XMLTree& state_tree, const std::string& xmlpath);
 };
 
+
 } // namespace ARDOUR
 
 #endif /* __ardour_session_h__ */
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index fe12073ca4..7165412f01 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -206,6 +206,8 @@ Session::Session (AudioEngine &eng,
 	, state_tree (0)
 	, state_was_pending (false)
 	, _state_of_the_state (StateOfTheState(CannotSave|InitialConnecting|Loading))
+	, _suspend_save (0)
+	, _save_queued (false)
 	, _last_roll_location (0)
 	, _last_roll_or_reversal_location (0)
 	, _last_record_location (0)
diff --git a/libs/ardour/session_state.cc b/libs/ardour/session_state.cc
index e9b8452045..3dc0a99f37 100644
--- a/libs/ardour/session_state.cc
+++ b/libs/ardour/session_state.cc
@@ -693,6 +693,12 @@ Session::save_state (string snapshot_name, bool pending, bool switch_to_snapshot
 		return 1;
 	}
 
+	if (g_atomic_int_get(&_suspend_save)) {
+		_save_queued = true;
+		return 1;
+	}
+	_save_queued = false;
+
 	if (!_engine.connected ()) {
 		error << string_compose (_("the %1 audio engine is not connected and state saving would lose all I/O connections. Session not saved"),
                                          PROGRAM_NAME)