* the refcount drops to 0, any memory and metadata pointed to by the buffer is
* unreffed as well. Buffers allocated from a #GstBufferPool will be returned to
* the pool when the refcount drops to 0.
+ *
+ * The #GstParentBufferMeta is a meta which can be attached to a #GstBuffer
+ * to hold a reference to another buffer that is only released when the child
+ * #GstBuffer is released.
+ *
+ * Typically, #GstParentBufferMeta is used when the child buffer is directly
+ * using the #GstMemory of the parent buffer, and wants to prevent the parent
+ * buffer from being returned to a buffer pool until the #GstMemory is available
+ * for re-use. (Since: 1.6)
+ *
*/
#include "gst_private.h"
* gst_buffer_copy_region:
* @parent: a #GstBuffer.
* @flags: the #GstBufferCopyFlags
- * @offset: the offset into parent #GstBuffer at which the new sub-buffer
+ * @offset: the offset into parent #GstBuffer at which the new sub-buffer
* begins.
* @size: the size of the new #GstBuffer sub-buffer, in bytes. If -1, all
* data is copied.
* Creates a sub-buffer from @parent at @offset and @size.
* This sub-buffer uses the actual memory space of the parent buffer.
* This function will copy the offset and timestamp fields when the
- * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
+ * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
* #GST_BUFFER_OFFSET_NONE.
* If @offset equals 0 and @size equals the total size of @buffer, the
* duration and offset end fields are also copied. If not they will be set
*dest_size = gst_buffer_extract (buffer, offset, *dest, size);
}
+
+GST_DEBUG_CATEGORY (gst_parent_buffer_meta_debug);
+
+/**
+ * gst_buffer_add_parent_buffer_meta:
+ * @buffer: (transfer none): a #GstBuffer
+ * @ref: (transfer none): a #GstBuffer to ref
+ *
+ * Add a #GstParentBufferMeta to @buffer that holds a reference on
+ * @ref until the buffer is freed.
+ *
+ * Returns: (transfer none): The #GstParentBufferMeta that was added to the buffer
+ *
+ * Since: 1.6
+ */
+GstParentBufferMeta *
+gst_buffer_add_parent_buffer_meta (GstBuffer * buffer, GstBuffer * ref)
+{
+ GstParentBufferMeta *meta;
+
+ g_return_val_if_fail (GST_IS_BUFFER (ref), NULL);
+
+ meta =
+ (GstParentBufferMeta *) gst_buffer_add_meta (buffer,
+ GST_PARENT_BUFFER_META_INFO, NULL);
+
+ if (!meta)
+ return NULL;
+
+ meta->buffer = gst_buffer_ref (ref);
+
+ return meta;
+}
+
+static gboolean
+_gst_parent_buffer_meta_transform (GstBuffer * dest, GstMeta * meta,
+ GstBuffer * buffer, GQuark type, gpointer data)
+{
+ GstParentBufferMeta *dmeta, *smeta;
+
+ smeta = (GstParentBufferMeta *) meta;
+
+ if (GST_META_TRANSFORM_IS_COPY (type)) {
+ /* copy over the reference to the parent buffer.
+ * Usually, this meta means we need to keep the parent buffer
+ * alive because one of the child memories is in use, which
+ * might not be the case if memory is deep copied or sub-regioned,
+ * but we can't tell, so keep the meta */
+ dmeta = gst_buffer_add_parent_buffer_meta (dest, smeta->buffer);
+ if (!dmeta)
+ return FALSE;
+
+ GST_CAT_DEBUG (gst_parent_buffer_meta_debug,
+ "copy buffer reference metadata");
+ }
+ return TRUE;
+}
+
+static void
+_gst_parent_buffer_meta_free (GstParentBufferMeta * parent_meta,
+ GstBuffer * buffer)
+{
+ GST_CAT_DEBUG (gst_parent_buffer_meta_debug,
+ "Dropping reference on buffer %p", parent_meta->buffer);
+ gst_buffer_unref (parent_meta->buffer);
+}
+
+static gboolean
+_gst_parent_buffer_meta_init (GstParentBufferMeta * parent_meta,
+ gpointer params, GstBuffer * buffer)
+{
+ static volatile gsize _init;
+
+ if (g_once_init_enter (&_init)) {
+ GST_DEBUG_CATEGORY_INIT (gst_parent_buffer_meta_debug, "glbufferrefmeta", 0,
+ "glbufferrefmeta");
+ g_once_init_leave (&_init, 1);
+ }
+
+ parent_meta->buffer = NULL;
+
+ return TRUE;
+}
+
+GType
+gst_parent_buffer_meta_api_get_type (void)
+{
+ static volatile GType type = 0;
+ static const gchar *tags[] = { NULL };
+
+ if (g_once_init_enter (&type)) {
+ GType _type = gst_meta_api_type_register ("GstParentBufferMetaAPI", tags);
+ g_once_init_leave (&type, _type);
+ }
+
+ return type;
+}
+
+/**
+ * gst_parent_buffer_meta_get_info:
+ *
+ * Get the global #GstMetaInfo describing the #GstParentBufferMeta meta.
+ *
+ * Returns: (transfer none): The #GstMetaInfo
+ *
+ * Since: 1.6
+ */
+const GstMetaInfo *
+gst_parent_buffer_meta_get_info (void)
+{
+ static const GstMetaInfo *meta_info = NULL;
+
+ if (g_once_init_enter (&meta_info)) {
+ const GstMetaInfo *meta =
+ gst_meta_register (gst_parent_buffer_meta_api_get_type (),
+ "GstParentBufferMeta",
+ sizeof (GstParentBufferMeta),
+ (GstMetaInitFunction) _gst_parent_buffer_meta_init,
+ (GstMetaFreeFunction) _gst_parent_buffer_meta_free,
+ _gst_parent_buffer_meta_transform);
+ g_once_init_leave (&meta_info, meta);
+ }
+
+ return meta_info;
+}
*/
#define gst_value_get_buffer(v) GST_BUFFER_CAST (g_value_get_boxed(v))
+typedef struct _GstParentBufferMeta GstParentBufferMeta;
+
+/**
+ * GstParentBufferMeta:
+ * @parent: the parent #GstMeta structure
+ * @buffer: the #GstBuffer on which a reference is being held.
+ *
+ * The #GstParentBufferMeta is a #GstMeta which can be attached to a #GstBuffer
+ * to hold a reference to another buffer that is only released when the child
+ * #GstBuffer is released.
+ *
+ * Typically, #GstParentBufferMeta is used when the child buffer is directly
+ * using the #GstMemory of the parent buffer, and wants to prevent the parent
+ * buffer from being returned to a buffer pool until the #GstMemory is available
+ * for re-use.
+ *
+ * (Since: 1.6)
+ */
+struct _GstParentBufferMeta
+{
+ GstMeta parent;
+
+ /*< public >*/
+ GstBuffer *buffer;
+};
+
+GType gst_parent_buffer_meta_api_get_type (void);
+#define GST_TYPE_PARENT_BUFFER_META_API_TYPE (gst_parent_buffer_meta_api_get_type())
+
+/**
+ * gst_buffer_get_parent_buffer_meta:
+ * @b: a #GstBuffer
+ *
+ * Find and return a #GstParentBufferMeta if one exists on the
+ * buffer
+ */
+#define gst_buffer_get_parent_buffer_meta(b) \
+ ((GstParentBufferMeta*)gst_buffer_get_meta((b),GST_PARENT_BUFFER_META_API_TYPE))
+
+const GstMetaInfo *gst_parent_buffer_meta_get_info (void);
+#define GST_PARENT_BUFFER_META_INFO (gst_parent_buffer_meta_get_info())
+
+/* implementation */
+GstParentBufferMeta *gst_buffer_add_parent_buffer_meta (GstBuffer *buffer,
+ GstBuffer *ref);
+
G_END_DECLS
#endif /* __GST_BUFFER_H__ */
projects / platform / upstream / gstreamer.git / commitdiff