lvs: add require_feature checks

Plugins can report what host features they need. Since we start to implement host feature
check which plugins we can no suuport.

ext/lv2/gstlv2.c

@@ -39,6 +39,7 @@
 
 #include <string.h>
 #include "gstlv2.h"
+#include "gstlv2utils.h"
 
 #include <gst/audio/audio-channels.h>
 #include <lv2/lv2plug.in/ns/ext/port-groups/port-groups.h>
@@ -64,7 +65,6 @@ lv2_plugin_discover (GstPlugin * plugin)
       i = lilv_plugins_next (plugins, i)) {
     const LilvPlugin *lv2plugin = lilv_plugins_get (plugins, i);
     const gchar *plugin_uri, *p;
-    LilvNodes *required_features;
     gchar *type_name;
     GHashTable *port_groups = g_hash_table_new_full (g_str_hash, g_str_equal,
         g_free, NULL);
@@ -84,11 +84,8 @@ lv2_plugin_discover (GstPlugin * plugin)
       goto next;
 
     /* check if we support the required host features */
-    required_features = lilv_plugin_get_required_features (lv2plugin);
+    if (!gst_lv2_check_required_features (lv2plugin)) {
-    if (required_features) {
       GST_FIXME ("lv2 plugin %s needs host features", plugin_uri);
-      // TODO: implement host features, will be passed to
-      // lilv_plugin_instantiate()
       goto next;
     }
 

ext/lv2/gstlv2utils.c

@@ -22,6 +22,8 @@
 #include "config.h"
 #endif
 
+#include "string.h"
+
 #include "gstlv2.h"
 #include "gstlv2utils.h"
 
@@ -67,6 +69,41 @@ static const LV2_Feature *lv2_features[] = {
   NULL
 };
 
+gboolean
+gst_lv2_check_required_features (const LilvPlugin * lv2plugin)
+{
+  LilvNodes *required_features = lilv_plugin_get_required_features (lv2plugin);
+  if (required_features) {
+    LilvIter *i;
+    gint j;
+    gboolean missing = FALSE;
+
+    for (i = lilv_nodes_begin (required_features);
+        !lilv_nodes_is_end (required_features, i);
+        i = lilv_nodes_next (required_features, i)) {
+      const LilvNode *required_feature = lilv_nodes_get (required_features, i);
+      const char *required_feature_uri = lilv_node_as_uri (required_feature);
+      missing = TRUE;
+
+      for (j = 0; lv2_features[j]; j++) {
+        if (!strcmp (lv2_features[j]->URI, required_feature_uri)) {
+          missing = FALSE;
+          break;
+        }
+      }
+      if (missing) {
+        GST_FIXME ("lv2 plugin %s needs host feature: %s",
+            lilv_node_as_uri (lilv_plugin_get_uri (lv2plugin)),
+            required_feature_uri);
+        break;
+      }
+    }
+    lilv_nodes_free (required_features);
+    return (!missing);
+  }
+  return TRUE;
+}
+
 /* api helpers */
 
 void

ext/lv2/gstlv2utils.h

@@ -85,6 +85,7 @@ struct _GstLV2Class
   GArray *control_out_ports; /**< Array of GstLV2Port */
 };
 
+gboolean gst_lv2_check_required_features (const LilvPlugin *lv2plugin);
 
 void gst_lv2_init (GstLV2 * lv2, GstLV2Class * lv2_class);
 void gst_lv2_finalize (GstLV2 * lv2);
@@ -92,7 +93,6 @@ void gst_lv2_finalize (GstLV2 * lv2);
 gboolean gst_lv2_setup (GstLV2 * lv2, unsigned long rate);
 gboolean gst_lv2_cleanup (GstLV2 * lv2, GstObject *obj);
 
-
 void gst_lv2_object_set_property (GstLV2 * lv2, GObject * object,
     guint prop_id, const GValue * value, GParamSpec * pspec);
 void gst_lv2_object_get_property (GstLV2 * lv2, GObject * object,