Prepare to allow to disable latency-compensation

Previously "zero custom/user latency" meant "default plugin latency".
This is now saved in a separate boolean allowing a user to reduce a
processor's latency to zero.

This also prepares for a global switch to use zero latency throughout
the whole session.

1 files changed, 42 insertions, 0 deletions

diff --git a/libs/ardour/latent.cc b/libs/ardour/latent.cc
new file mode 100644
index 0000000000..44ec0e7d30
--- /dev/null
+++ b/libs/ardour/latent.cc
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2018 Robin Gareus <robin@gareus.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include "pbd/xml++.h"
+
+#include "ardour/latent.h"
+
+using namespace ARDOUR;
+
+bool ARDOUR::Latent::_zero_latency = false;
+
+int
+Latent::set_state (const XMLNode& node, int version)
+{
+	node.get_property ("user-latency", _user_latency);
+	if (!node.get_property ("use-user-latency", _use_user_latency)) {
+		_use_user_latency = _user_latency > 0;
+	}
+	return 0;
+}
+
+void
+Latent::add_state (XMLNode* node) const
+{
+	node->set_property ("user-latency", _user_latency);
+	node->set_property ("use-user-latency", _use_user_latency);
+}