proxy: when requesting Props, only try to enum them if the proxy supports them

otherwise we get stuck waiting for the param event
and we get warnings on the debug log

lib/wp/proxy.c

@@ -284,6 +284,43 @@ wp_proxy_get_gobj_property (GObject * object, guint property_id, GValue * value,
   }
 }
 
+static void
+wp_proxy_enable_feature_props (WpProxy * self)
+{
+  WpProxyClass *klass = WP_PROXY_GET_CLASS (self);
+  struct spa_param_info *param_info;
+  guint n_params;
+  guint have_propinfo = FALSE, have_props = FALSE;
+  uint32_t ids[] = { SPA_PARAM_Props };
+
+  /* check if we actually have props */
+  param_info = klass->get_param_info (self, &n_params);
+  for (guint i = 0; i < n_params; i++) {
+    if (param_info[i].id == SPA_PARAM_PropInfo)
+      have_propinfo = TRUE;
+    else if (param_info[i].id == SPA_PARAM_Props)
+      have_props = TRUE;
+  }
+
+  if (have_propinfo && have_props) {
+    if (!klass->enum_params || !klass->subscribe_params) {
+      wp_proxy_augment_error (self, g_error_new (WP_DOMAIN_LIBRARY,
+            WP_LIBRARY_ERROR_INVARIANT,
+            "Proxy does not support enum/subscribe params API"));
+      return;
+    }
+
+    klass->enum_params (self, SPA_PARAM_PropInfo, 0, -1, NULL);
+    klass->subscribe_params (self, ids, SPA_N_ELEMENTS (ids));
+  } else {
+    /* declare as ready with no props */
+    wp_proxy_set_feature_ready (self, WP_PROXY_FEATURE_PROPS);
+  }
+
+  g_signal_handlers_disconnect_by_func (self,
+      wp_proxy_enable_feature_props, self);
+}
+
 static void
 wp_proxy_default_augment (WpProxy * self, WpProxyFeatures features)
 {
@@ -310,19 +347,13 @@ wp_proxy_default_augment (WpProxy * self, WpProxyFeatures features)
   }
 
   if (features & WP_PROXY_FEATURE_PROPS && !priv->props) {
-    WpProxyClass *klass = WP_PROXY_GET_CLASS (self);
-    uint32_t ids[] = { SPA_PARAM_Props };
-
-    if (!klass->enum_params || !klass->subscribe_params) {
-      wp_proxy_augment_error (self, g_error_new (WP_DOMAIN_LIBRARY,
-            WP_LIBRARY_ERROR_OPERATION_FAILED,
-            "Proxy does not support enum/subscribe params API"));
-      return;
-    }
-
     wp_proxy_set_props (self, wp_props_new (WP_PROPS_MODE_CACHE, self));
-    klass->enum_params (self, SPA_PARAM_PropInfo, 0, -1, NULL);
-    klass->subscribe_params (self, ids, SPA_N_ELEMENTS (ids));
+
+    if (priv->ft_ready & WP_PROXY_FEATURE_INFO)
+      wp_proxy_enable_feature_props (self);
+    else
+      g_signal_connect (self, "notify::param-info",
+          G_CALLBACK (wp_proxy_enable_feature_props), self);
   }
 }