From f4712be632b28d3078fed22f845c1d3eae1f3ad0 Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Sun, 30 Sep 2012 22:05:57 +0000
Subject: Refuse to instantiate plugins which require unsupported features.
 Support LV2 buf-size extension (with all features).

git-svn-id: http://svn.drobilla.net/lad/trunk/jalv@4796 a436a847-0d15-0410-975c-d299462d15a1
---
 NEWS       |  2 ++
 src/jalv.c | 34 +++++++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index cd37a43..f417d7c 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,8 @@ jalv (9999) unstable;
   * Tolerate loading presets with port values that aren't xsd:decimal
   * Notify plugins of Jack transport changes by sending events (an atom:Blank
     with properties from the LV2 time extension)
+  * Refuse to instantiate plugins which require unsupported features
+  * Support LV2 buf-size extension (with all features)
   * Add Gtk3 UI
   * Port to Windows
   * Fix Jack Session support
diff --git a/src/jalv.c b/src/jalv.c
index f4bb680..b88f1e3 100644
--- a/src/jalv.c
+++ b/src/jalv.c
@@ -121,15 +121,36 @@ static LV2_Feature schedule_feature  = { LV2_WORKER__schedule, NULL };
 static LV2_Feature log_feature       = { LV2_LOG__log, NULL };
 static LV2_Feature options_feature   = { LV2_OPTIONS__options, NULL };
 
-const LV2_Feature* features[9] = {
+/** These features have no data */
+static LV2_Feature buf_size_features[3] = {
+	{ LV2_BUF_SIZE__powerOf2BlockLength, NULL },
+	{ LV2_BUF_SIZE__fixedBlockLength, NULL },
+	{ LV2_BUF_SIZE__boundedBlockLength, NULL } };
+
+const LV2_Feature* features[12] = {
 	&uri_map_feature, &map_feature, &unmap_feature,
 	&make_path_feature,
 	&schedule_feature,
 	&log_feature,
 	&options_feature,
+	&buf_size_features[0],
+	&buf_size_features[1],
+	&buf_size_features[2],
 	NULL
 };
 
+/** Return true iff Jalv supports the given feature. */
+static bool
+feature_is_supported(const char* uri)
+{
+	for (const LV2_Feature*const* f = features; *f; ++f) {
+		if (!strcmp(uri, (*f)->URI)) {
+			return true;
+		}
+	}
+	return false;
+}
+
 /** Abort and exit on error */
 static void
 die(const char* msg)
@@ -865,6 +886,17 @@ main(int argc, char** argv)
 		return EXIT_FAILURE;
 	}
 
+	/* Check that any required features are supported */
+	LilvNodes* req_feats = lilv_plugin_get_required_features(jalv.plugin);
+	LILV_FOREACH(nodes, f, req_feats) {
+		const char* uri = lilv_node_as_uri(lilv_nodes_get(req_feats, f));
+		if (!feature_is_supported(uri)) {
+			fprintf(stderr, "Feature %s is not supported\n", uri);
+			lilv_world_free(world);
+			return EXIT_FAILURE;
+		}
+	}
+
 	/* Get a plugin UI */
 	const char* native_ui_type_uri = jalv_native_ui_type(&jalv);
 	if (!jalv.opts.generic_ui && native_ui_type_uri) {
-- 
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