Add state:threadSafeRestore feature

3 files changed, 27 insertions, 7 deletions

diff --git a/lv2/lv2plug.in/ns/ext/state/lv2-state.doap.ttl b/lv2/lv2plug.in/ns/ext/state/lv2-state.doap.ttl
index 6af90ea..feacdee 100644
--- a/lv2/lv2plug.in/ns/ext/state/lv2-state.doap.ttl
+++ b/lv2/lv2plug.in/ns/ext/state/lv2-state.doap.ttl
@@ -15,11 +15,13 @@
 	doap:maintainer <http://drobilla.net/drobilla#me> ;
 	doap:release [
 		doap:revision "2.1" ;
-		doap:created "2015-12-04" ;
+		doap:created "2016-07-31" ;
 		dcs:blame <http://drobilla.net/drobilla#me> ;
 		dcs:changeset [
 			dcs:item [
 				rdfs:label "Add LV2_STATE_ERR_NO_SPACE status flag."
+			] , [
+				rdfs:label "Add state:threadSafeRestore feature for dropout-free state restoration."
 			]
 		]
 	] , [
diff --git a/lv2/lv2plug.in/ns/ext/state/state.h b/lv2/lv2plug.in/ns/ext/state/state.h
index d446b30..0567e1b 100644
--- a/lv2/lv2plug.in/ns/ext/state/state.h
+++ b/lv2/lv2plug.in/ns/ext/state/state.h
@@ -35,12 +35,13 @@
 #define LV2_STATE_URI    "http://lv2plug.in/ns/ext/state"
 #define LV2_STATE_PREFIX LV2_STATE_URI "#"
 
-#define LV2_STATE__State            LV2_STATE_PREFIX "State"
-#define LV2_STATE__interface        LV2_STATE_PREFIX "interface"
-#define LV2_STATE__loadDefaultState LV2_STATE_PREFIX "loadDefaultState"
-#define LV2_STATE__makePath         LV2_STATE_PREFIX "makePath"
-#define LV2_STATE__mapPath          LV2_STATE_PREFIX "mapPath"
-#define LV2_STATE__state            LV2_STATE_PREFIX "state"
+#define LV2_STATE__State             LV2_STATE_PREFIX "State"
+#define LV2_STATE__interface         LV2_STATE_PREFIX "interface"
+#define LV2_STATE__loadDefaultState  LV2_STATE_PREFIX "loadDefaultState"
+#define LV2_STATE__makePath          LV2_STATE_PREFIX "makePath"
+#define LV2_STATE__mapPath           LV2_STATE_PREFIX "mapPath"
+#define LV2_STATE__state             LV2_STATE_PREFIX "state"
+#define LV2_STATE__threadSafeRestore LV2_STATE_PREFIX "threadSafeRestore"
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/lv2/lv2plug.in/ns/ext/state/state.ttl b/lv2/lv2plug.in/ns/ext/state/state.ttl
index 699ef45..a5b205e 100644
--- a/lv2/lv2plug.in/ns/ext/state/state.ttl
+++ b/lv2/lv2plug.in/ns/ext/state/state.ttl
@@ -347,3 +347,20 @@ char* save_myfile(LV2_State_Make_Path* make_path)
 }
 </pre>
 """ .
+
+state:threadSafeRestore
+	a lv2:Feature ;
+	rdfs:label "thread-safe restore" ;
+	lv2:documentation """
+<p>If a plugin supports this feature, its LV2_State_Interface::restore method
+is thread-safe and may be called concurrently with audio class functions.</p>
+
+<p>To support this feature, the host MUST pass a <a
+href="../worker/worker.html#schedule">work:schedule</a> feature to the restore
+method, which will be used to complete the state restoration.  The usual
+mechanics of the worker apply: the host will call the plugin's work method,
+which emits a response which is later applied in the audio thread.</p>
+
+<p>The host is not required to block run() while restore() and work() load the
+state, so this feature allows state to be restored without dropouts.</p>
+""" .