meta: add support to tagging the metadata

Add support for adding tags to the metadata. with some standard keys, this
should make it possible to describe what the metadata refers to. We should be
able to use this information to decide if a transformation destroys the metadata
or not.

diff --git a/gst/gstmeta.c b/gst/gstmeta.c
index 03a4a8f..ed68a23 100644 (file)
--- a/gst/gstmeta.c
+++ b/gst/gstmeta.c
@@ -54,6 +54,8 @@ _priv_gst_meta_initialize (void)
  * @init_func: a #GstMetaInitFunction
  * @free_func: a #GstMetaFreeFunction
  * @transform_func: a #GstMetaTransformFunction
+ * @tags: a NULL terminated array of strings describing what the metadata
+ *        contains info about.
  *
  * Register a new #GstMeta implementation.
  *
@@ -66,13 +68,16 @@ _priv_gst_meta_initialize (void)
 const GstMetaInfo *
 gst_meta_register (const gchar * api, const gchar * impl, gsize size,
     GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
-    GstMetaTransformFunction transform_func)
+    GstMetaTransformFunction transform_func, const gchar ** tags)
 {
   GstMetaInfo *info;
+  guint len, i;
+  GQuark *qtags;
 
   g_return_val_if_fail (api != NULL, NULL);
   g_return_val_if_fail (impl != NULL, NULL);
   g_return_val_if_fail (size != 0, NULL);
+  g_return_val_if_fail (tags != NULL, NULL);
 
   info = g_slice_new (GstMetaInfo);
   info->api = g_quark_from_string (api);
@@ -82,6 +87,12 @@ gst_meta_register (const gchar * api, const gchar * impl, gsize size,
   info->free_func = free_func;
   info->transform_func = transform_func;
 
+  len = g_strv_length ((gchar **) tags);
+  qtags = g_new0 (GQuark, len);
+  for (i = 0; i < len; i++)
+    qtags[i] = g_quark_from_static_string (tags[i]);
+  info->tags = qtags;
+
   GST_DEBUG ("register \"%s\" implementing \"%s\" of size %" G_GSIZE_FORMAT,
       api, impl, size);
 

diff --git a/gst/gstmeta.h b/gst/gstmeta.h
index 05c0493..2c70a36 100644 (file)
--- a/gst/gstmeta.h
+++ b/gst/gstmeta.h
@@ -161,6 +161,8 @@ typedef void (*GstMetaTransformFunction) (GstBuffer *transbuf,
  * @init_func: function for initializing the metadata
  * @free_func: function for freeing the metadata
  * @transform_func: function for transforming the metadata
+ * @tags: 0 terminated array of GQuarks describing what the metadata
+ *        contains info about
  *
  * The #GstMetaInfo provides information about a specific metadata
  * structure.
@@ -174,6 +176,8 @@ struct _GstMetaInfo {
   GstMetaFreeFunction        free_func;
   GstMetaTransformFunction   transform_func;
 
+  const GQuark              *tags;
+
   /*< private >*/
   gpointer _gst_reserved[GST_PADDING];
 };
@@ -182,7 +186,8 @@ const GstMetaInfo *  gst_meta_register        (const gchar *api, const gchar *im
                                                gsize size,
                                                GstMetaInitFunction        init_func,
                                                GstMetaFreeFunction        free_func,
-                                               GstMetaTransformFunction   transform_func);
+                                               GstMetaTransformFunction   transform_func,
+                                               const gchar **tags);
 const GstMetaInfo *  gst_meta_get_info        (const gchar * impl);
 
 G_END_DECLS

diff --git a/libs/gst/net/gstnetaddressmeta.c b/libs/gst/net/gstnetaddressmeta.c
index 043aab2..057ff79 100644 (file)
--- a/libs/gst/net/gstnetaddressmeta.c
+++ b/libs/gst/net/gstnetaddressmeta.c
@@ -61,13 +61,14 @@ const GstMetaInfo *
 gst_net_address_meta_get_info (void)
 {
   static const GstMetaInfo *meta_info = NULL;
+  static const gchar *tags[] = { "origin", NULL };
 
   if (meta_info == NULL) {
     meta_info = gst_meta_register ("GstNetAddressMeta", "GstNetAddressMeta",
         sizeof (GstNetAddressMeta),
         (GstMetaInitFunction) net_address_meta_init,
         (GstMetaFreeFunction) net_address_meta_free,
-        (GstMetaTransformFunction) net_address_meta_transform);
+        (GstMetaTransformFunction) net_address_meta_transform, tags);
   }
   return meta_info;
 }