don't double-load NestedSource nodes, which are listed both forthe parent/root region and all children; even better, don't list them twice anyway - just for the whole file parent/root region

git-svn-id: svn://localhost/ardour2/branches/3.0@9761 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/region.cc

@@ -1207,7 +1207,11 @@ Region::state ()
 		node->add_property (buf2, buf);
 	}
 
-	if (max_source_level() > 0) {
+	/* Only store nested sources for the whole-file region that acts
+	   as the parent/root of all regions using it.
+	*/
+
+	if (_whole_file && max_source_level() > 0) {
 
 		XMLNode* nested_node = new XMLNode (X_("NestedSource"));
 

libs/ardour/session_state.cc

@@ -1660,11 +1660,26 @@ Session::load_nested_sources (const XMLNode& node)
 
 	for (niter = nlist.begin(); niter != nlist.end(); ++niter) {
 		if ((*niter)->name() == "Source") {
-			try {
-				SourceFactory::create (*this, **niter, true);
+
+			/* it may already exist, so don't recreate it unnecessarily 
+			 */
+
+			XMLProperty* prop = (*niter)->property (X_("id"));
+			if (!prop) {
+				error << _("Nested source has no ID info in session state file! (ignored)") << endmsg;
+				continue;
 			}
-			catch (failed_constructor& err) {
-				error << string_compose (_("Cannot reconstruct nested source for region %1"), name()) << endmsg;
+
+			ID source_id (prop->value());
+
+			if (!source_by_id (source_id)) {
+
+				try {
+					SourceFactory::create (*this, **niter, true);
+				}
+				catch (failed_constructor& err) {
+					error << string_compose (_("Cannot reconstruct nested source for region %1"), name()) << endmsg;
+				}
 			}
 		}
 	}

libs/ardour/source_factory.cc

@@ -155,12 +155,13 @@ SourceFactory::create (Session& s, const XMLNode& node, bool defer_peaks)
 
 			try {
 				boost::shared_ptr<AudioPlaylistSource> ap (new AudioPlaylistSource (s, node));
-
+				
 				if (setup_peakfile (ap, true)) {
 					return boost::shared_ptr<Source>();
 				}
 
 				ap->check_for_analysis_data_on_disk ();
+
 				SourceCreated (ap);
 				return ap;