meta: flesh out the metadata transform

Flesh out the transform method. Add a type and extra info to the transform
function so that implementation can transform the metadata.
Remove the copy function and replace with the more generic transform.

gst/gstbuffer.c

@@ -359,8 +359,15 @@ gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
       GstMeta *meta = &walk->meta;
       const GstMetaInfo *info = meta->info;
 
-      if (info->copy_func)
-        info->copy_func (dest, meta, src, offset, size);
+      if (info->transform_func) {
+        GstMetaTransformCopy copy_data;
+
+        copy_data.offset = offset;
+        copy_data.size = size;
+
+        info->transform_func (dest, meta, src,
+            _gst_meta_transform_copy, &copy_data);
+      }
     }
   }
 }

gst/gstmeta.c

@@ -35,11 +35,15 @@
 static GHashTable *metainfo = NULL;
 static GRWLock lock;
 
+GQuark _gst_meta_transform_copy;
+
 void
 _priv_gst_meta_initialize (void)
 {
   g_rw_lock_init (&lock);
   metainfo = g_hash_table_new (g_str_hash, g_str_equal);
+
+  _gst_meta_transform_copy = g_quark_from_static_string ("copy");
 }
 
 /**
@@ -49,7 +53,6 @@ _priv_gst_meta_initialize (void)
  * @size: the size of the #GstMeta structure
  * @init_func: a #GstMetaInitFunction
  * @free_func: a #GstMetaFreeFunction
- * @copy_func: a #GstMetaCopyFunction
  * @transform_func: a #GstMetaTransformFunction
  *
  * Register a new #GstMeta implementation.
@@ -63,7 +66,7 @@ _priv_gst_meta_initialize (void)
 const GstMetaInfo *
 gst_meta_register (const gchar * api, const gchar * impl, gsize size,
     GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
-    GstMetaCopyFunction copy_func, GstMetaTransformFunction transform_func)
+    GstMetaTransformFunction transform_func)
 {
   GstMetaInfo *info;
 
@@ -77,7 +80,6 @@ gst_meta_register (const gchar * api, const gchar * impl, gsize size,
   info->size = size;
   info->init_func = init_func;
   info->free_func = free_func;
-  info->copy_func = copy_func;
   info->transform_func = transform_func;
 
   GST_DEBUG ("register \"%s\" implementing \"%s\" of size %" G_GSIZE_FORMAT,

gst/gstmeta.h

@@ -113,34 +113,45 @@ typedef gboolean (*GstMetaInitFunction) (GstMeta *meta, gpointer params, GstBuff
 typedef void (*GstMetaFreeFunction)     (GstMeta *meta, GstBuffer *buffer);
 
 /**
- * GstMetaCopyFunction:
- * @dest: a destination #GstBuffer
- * @meta: a #GstMeta
- * @buffer: a #GstBuffer
- * @offset: an offset
- * @size: a size
+ * gst_meta_transform_copy:
  *
- * Function called when the region at @offset and @size in @buffer is copied
- * into @dest. The function should update the metadata on @dest using @meta.
+ * GQuark for the "copy" transform.
  */
-typedef void (*GstMetaCopyFunction)     (GstBuffer *dest, GstMeta *meta,
-                                         GstBuffer *buffer, gsize offset, gsize size);
+GST_EXPORT GQuark _gst_meta_transform_copy;
+
+#define GST_META_TRANSFORM_IS_COPY(type) ((type) == _gst_meta_transform_copy)
+
+/**
+ * GstMetaTransformDataCopy:
+ * @offset: the offset to copy
+ * @size: the size to copy
+ *
+ * Extra data passed to a "copy" transform #GstMetaTransformFunction.
+ */
+typedef struct {
+  gsize offset;
+  gsize size;
+} GstMetaTransformCopy;
+
 /**
  * GstMetaTransformFunction:
  * @transbuf: a #GstBuffer
  * @meta: a #GstMeta
  * @buffer: a #GstBuffer
+ * @type: the transform type
  * @data: transform specific data.
  *
  * Function called for each @meta in @buffer as a result of performing a
- * transformation on @transbuf. Additional type specific transform data
- * is passed to the function.
+ * transformation on @transbuf. Additional @type specific transform data
+ * is passed to the function as @data.
  *
- * Implementations should check the type of the transform @data and parse
- * additional type specific field that should be used to perform the transform.
+ * Implementations should check the @type of the transform and parse
+ * additional type specific fields in @data that should be used to update
+ * the metadata on @transbuf.
  */
-typedef void (*GstMetaTransformFunction) (GstBuffer *transbuf, GstMeta *meta,
-                                          GstBuffer *buffer, gpointer data);
+typedef void (*GstMetaTransformFunction) (GstBuffer *transbuf,
+                                          GstMeta *meta, GstBuffer *buffer,
+                                          GQuark type, gpointer data);
 
 /**
  * GstMetaInfo:
@@ -149,7 +160,6 @@ typedef void (*GstMetaTransformFunction) (GstBuffer *transbuf, GstMeta *meta,
  * @size: size of the metadata
  * @init_func: function for initializing the metadata
  * @free_func: function for freeing the metadata
- * @copy_func: function for copying the metadata
  * @transform_func: function for transforming the metadata
  *
  * The #GstMetaInfo provides information about a specific metadata
@@ -162,7 +172,6 @@ struct _GstMetaInfo {
 
   GstMetaInitFunction        init_func;
   GstMetaFreeFunction        free_func;
-  GstMetaCopyFunction        copy_func;
   GstMetaTransformFunction   transform_func;
 
   /*< private >*/
@@ -173,7 +182,6 @@ const GstMetaInfo *  gst_meta_register        (const gchar *api, const gchar *im
                                                gsize size,
                                                GstMetaInitFunction        init_func,
                                                GstMetaFreeFunction        free_func,
-                                               GstMetaCopyFunction        copy_func,
                                                GstMetaTransformFunction   transform_func);
 const GstMetaInfo *  gst_meta_get_info        (const gchar * impl);
 

libs/gst/net/gstnetaddressmeta.c

@@ -42,10 +42,11 @@ net_address_meta_init (GstNetAddressMeta * meta, gpointer params,
 }
 
 static void
-net_address_meta_copy (GstBuffer * copybuf, GstNetAddressMeta * meta,
-    GstBuffer * buffer, gsize offset, gsize size)
+net_address_meta_transform (GstBuffer * transbuf, GstNetAddressMeta * meta,
+    GstBuffer * buffer, GQuark type, gpointer data)
 {
-  gst_buffer_add_net_address_meta (copybuf, meta->addr);
+  /* we always copy no matter what transform */
+  gst_buffer_add_net_address_meta (transbuf, meta->addr);
 }
 
 static void
@@ -66,8 +67,7 @@ gst_net_address_meta_get_info (void)
         sizeof (GstNetAddressMeta),
         (GstMetaInitFunction) net_address_meta_init,
         (GstMetaFreeFunction) net_address_meta_free,
-        (GstMetaCopyFunction) net_address_meta_copy,
-        (GstMetaTransformFunction) NULL);
+        (GstMetaTransformFunction) net_address_meta_transform);
   }
   return meta_info;
 }

tests/check/gst/gstmeta.c

@@ -80,32 +80,36 @@ test_free_func (GstMetaTest * meta, GstBuffer * buffer)
 }
 
 static void
-test_copy_func (GstBuffer * copybuf, GstMetaTest * meta,
-    GstBuffer * buffer, gsize offset, gsize size)
+test_transform_func (GstBuffer * transbuf, GstMetaTest * meta,
+    GstBuffer * buffer, GQuark type, gpointer data)
 {
   GstMetaTest *test;
 
-  GST_DEBUG ("copy called from buffer %p to %p, meta %p, %u-%u", buffer,
-      copybuf, meta, offset, size);
+  GST_DEBUG ("transform %s called from buffer %p to %p, meta %p",
+      g_quark_to_string (type), buffer, transbuf, meta);
 
-  test = GST_META_TEST_ADD (copybuf);
-  if (offset == 0) {
-    /* same offset, copy timestamps */
-    test->pts = meta->pts;
-    test->dts = meta->dts;
-    if (size == gst_buffer_get_size (buffer)) {
-      /* same size, copy duration */
-      test->duration = meta->duration;
+  if (GST_META_TRANSFORM_IS_COPY (type)) {
+    GstMetaTransformCopy *copy_data = data;
+
+    test = GST_META_TEST_ADD (transbuf);
+    if (copy_data->offset == 0) {
+      /* same offset, copy timestamps */
+      test->pts = meta->pts;
+      test->dts = meta->dts;
+      if (copy_data->size == gst_buffer_get_size (buffer)) {
+        /* same size, copy duration */
+        test->duration = meta->duration;
+      } else {
+        /* else clear */
+        test->duration = GST_CLOCK_TIME_NONE;
+      }
     } else {
-      /* else clear */
-      test->duration = GST_CLOCK_TIME_NONE;
+      test->pts = -1;
+      test->dts = -1;
+      test->duration = -1;
     }
-  } else {
-    test->pts = -1;
-    test->dts = -1;
-    test->duration = -1;
+    test->clock_rate = meta->clock_rate;
   }
-  test->clock_rate = meta->clock_rate;
 }
 
 static const GstMetaInfo *
@@ -118,7 +122,7 @@ gst_meta_test_get_info (void)
         sizeof (GstMetaTest),
         (GstMetaInitFunction) test_init_func,
         (GstMetaFreeFunction) test_free_func,
-        (GstMetaCopyFunction) test_copy_func, (GstMetaTransformFunction) NULL);
+        (GstMetaTransformFunction) test_transform_func);
   }
   return meta_test_info;
 }

win32/common/libgstreamer.def

@@ -43,6 +43,7 @@ EXPORTS
 	_gst_disable_registry_cache DATA
 	_gst_element_error_printf
 	_gst_event_type DATA
+	_gst_meta_transform_copy DATA
 	_gst_plugin_loader_client_run
 	_gst_sample_type DATA
 	_gst_structure_type DATA