From 63d81d2419e08b357af2e9d94d077eb1556a72a6 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Fri, 4 Jul 2014 15:50:34 +0200
Subject: [PATCH] purge states of Audio-backends that are N/A

fixes crashes/assert() when using different builds while
sharing ardour.rc with n/a engine backends marked active.
---
 gtk2_ardour/engine_dialog.cc | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/gtk2_ardour/engine_dialog.cc b/gtk2_ardour/engine_dialog.cc
index 27cf9b7719..437aea7d39 100644
--- a/gtk2_ardour/engine_dialog.cc
+++ b/gtk2_ardour/engine_dialog.cc
@@ -1337,6 +1337,21 @@ EngineControl::set_state (const XMLNode& root)
 
 	/* now see if there was an active state and switch the setup to it */
 
+	// purge states of backend that are not available in this built
+	vector<const ARDOUR::AudioBackendInfo*> backends = ARDOUR::AudioEngine::instance()->available_backends();
+	vector<std::string> backend_names;
+
+	for (vector<const ARDOUR::AudioBackendInfo*>::const_iterator i = backends.begin(); i != backends.end(); ++i) {
+		backend_names.push_back((*i)->name);
+	}
+	for (StateList::iterator i = states.begin(); i != states.end();) {
+		if (std::find(backend_names.begin(), backend_names.end(), (*i)->backend) == backend_names.end()) {
+			i = states.erase(i);
+		} else {
+			++i;
+		}
+	}
+
 	for (StateList::const_iterator i = states.begin(); i != states.end(); ++i) {
 
 		if ((*i)->active) {