Clean up _before XMLNode in AutomationList if no automation write occurred.

5 files changed, 22 insertions, 11 deletions

diff --git a/libs/ardour/ardour/automation_control.h b/libs/ardour/ardour/automation_control.h
index 9190b71677..b26d781e2f 100644
--- a/libs/ardour/ardour/automation_control.h
+++ b/libs/ardour/ardour/automation_control.h
@@ -107,7 +107,7 @@ public:
 	const ParameterDescriptor& desc() const { return _desc; }
 
 	const ARDOUR::Session& session() const { return _session; }
-	void commit_transaction ();
+	void commit_transaction (bool did_write);
 
 protected:
 
diff --git a/libs/ardour/ardour/automation_list.h b/libs/ardour/ardour/automation_list.h
index 67ee6234bb..37a30acd03 100644
--- a/libs/ardour/ardour/automation_list.h
+++ b/libs/ardour/ardour/automation_list.h
@@ -114,6 +114,7 @@ class LIBARDOUR_API AutomationList : public PBD::StatefulDestructible, public Ev
 	bool operator!= (const AutomationList &) const;
 
 	XMLNode* before () { return _before; }
+	void clear_history ();
   private:
 	void create_curve_if_necessary ();
 	int deserialize_events (const XMLNode&);
diff --git a/libs/ardour/automatable.cc b/libs/ardour/automatable.cc
index 27ac7d8401..9670f68689 100644
--- a/libs/ardour/automatable.cc
+++ b/libs/ardour/automatable.cc
@@ -398,9 +398,7 @@ Automatable::transport_stopped (framepos_t now)
 
 		l->stop_touch (true, now);
 
-		if (list_did_write) {
-			c->commit_transaction ();
-		}
+		c->commit_transaction (list_did_write);
 
 		l->write_pass_finished (now, Config->get_automation_thinning_factor ());
 
diff --git a/libs/ardour/automation_control.cc b/libs/ardour/automation_control.cc
index 671cd6e977..1f507b7015 100644
--- a/libs/ardour/automation_control.cc
+++ b/libs/ardour/automation_control.cc
@@ -163,11 +163,15 @@ AutomationControl::stop_touch(bool mark, double when)
 }
 
 void
-AutomationControl::commit_transaction ()
+AutomationControl::commit_transaction (bool did_write)
 {
-	if (alist ()->before ()) {
-		_session.begin_reversible_command (string_compose (_("record %1 automation"), name ()));
-		_session.commit_reversible_command (new MementoCommand<AutomationList> (*alist ().get (), alist ()->before (), &alist ()->get_state ()));
+	if (did_write) {
+		if (alist ()->before ()) {
+			_session.begin_reversible_command (string_compose (_("record %1 automation"), name ()));
+			_session.commit_reversible_command (new MementoCommand<AutomationList> (*alist ().get (), alist ()->before (), &alist ()->get_state ()));
+		}
+	} else {
+		alist ()->clear_history ();
 	}
 }
 
diff --git a/libs/ardour/automation_list.cc b/libs/ardour/automation_list.cc
index afff85c1f8..9d8bfffc93 100644
--- a/libs/ardour/automation_list.cc
+++ b/libs/ardour/automation_list.cc
@@ -191,9 +191,6 @@ AutomationList::set_automation_state (AutoState s)
 {
 	if (s != _state) {
 		_state = s;
-		if (s == Write) {
-			_before = &get_state ();
-		}
 		automation_state_changed (s); /* EMIT SIGNAL */
 	}
 }
@@ -220,6 +217,7 @@ void
 AutomationList::write_pass_finished (double when, double thinning_factor)
 {
 	ControlList::write_pass_finished (when, thinning_factor);
+	/* automation control has deleted this or it is now owned by the session undo stack */
 	_before = 0;
 }
 
@@ -256,6 +254,16 @@ AutomationList::stop_touch (bool mark, double)
         }
 }
 
+/* _before may be owned by the undo stack,
+ * so we have to be careful about doing this.
+*/
+void
+AutomationList::clear_history ()
+{
+	delete _before;
+	_before = 0;
+}
+
 void
 AutomationList::thaw ()
 {